FINAL  SUMMARY REPORT OF
                    MINERAL  INDUSTRY PROCESSING WASTES
Prepared
                             *. t e ;
                                                        3c) . / ' «
             Douglas K. Maxwe]
             Processing Wastes Ta'sk Coordinator
             Camp Dresser & McKee  Inc., Denver,  CO
Approved by:
                            Date:
             Linda JX/fir"6wn   //
             Work Alignment/flanagei
             COM Federal Programs Corporation
Approved by:
                            Date:
William A. Koski
Project Manager
COM Federal Programs Corporation


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                                  FOREWORD
This report was developed and prepared by CDM Federal Programs Corporation,
and reviewed by EPA under EPA Contract No. 68-01-6939, Performance of
Remedial Responses Activities at Uncontrolled Hazardous Waste Sites (REM
II).  Just prior to the actual submittal of this report to EPA Office of
Solid Waste, CDM's work was shifted from the REM II Contract to the RCRA
Implementation Support, EPA Contract No. 68-01-7374.
                                    iv

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                             TABLE OF CONTENTS

                                                                       Page

Executive Summary 	     ES-1

1.0  Introduction	      1-1

     1.1  Statutory and Regulatory Background 	      1-1
     1.2  Purpose of this Report 	      1-1
     1.3  Preparation of the Processing Waste Summaries  	      1-2
     1. 4  Summary and Conclusions 	      1-2

          I.A.I  Nonmetals Not Recommended for  Further Study 	      1-6
          1.4.2  Nonmetals Recommended for Further Study 	     1-11
          1.4.3  Metals Not Recommended for Further Study 	     1-14
          1.4.4  Metals Recommended for Further Study 	     1-15

     1.5  References 	     1-19

2.0  Nonmetal Industries 	      2-1

     Introduction 	'	      2-1

          Diatomite 	      2-2
          Garnet 	      2-3
          Gemstones 	      2-4
          Glauconite 	      2-5
          Gypsum 	      2-6
          Lime, Limestone, and Dolomite 	      2-8
          Lithium	     2-11
          Mica 	     2-16
          Peat 	     2-23
          Perlite 	     2-24
          Potash 	     2-28
          Pumice 	     2-34
          Pyrophylli te 	     2-36
          Salt and Rock Salt (Halite)  	     2-37
          Sand and Gravel and Crushed Stone  	     2-41
          Soda Ash 	     2-43
          Sodium Sulfate 	     2-47
          Staurolite 	     2-52
          Building Stone 	     2-54
          Sulfur 	    2-55
          Talc	    2-57
          Tripoli	    2-59
          Vermiculite  	    2-60
          Uollastonite	    2-64
          Barite 	    2-65
          Biluminous Minerals  	    2-70
          Boron Materials  	    2-77

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          Bromine 	     2-85
          Clays 	     2-89
          Coal:  Beneficiation, Gasification,  Liquification,
               Coking 	     2-93
          Feldspar 	    2-101
          Fluorspar 	    2-104
          Iodine 	    2-109
          Kyanite 	    2-113
          Olivine	    2-116
          Phosphate Rock, Phosphoric Acid and  Phosphorous 	    2-120
          Silica	    2-128
          Asbestos 	..,...„..«	    2-132
          Shale 	„..„.,„.	    2-135

3.0  Metal Industries 	-  : *...-.,.      3-1

     Introduction 	„,.	. >..      3-1

          Arsenic	      3-2
          Cobalt	      3-4
          Mercury 	.....„,. * „.-	      3-9
          Nickel 	oo	     3-14
          Scandium 	     3-20
          Antimony	.,...=,..	     3-31
          Beryllium ..,..,,..,	.'	     3-46
          Bismuth .„,,.....	     3-53
          Cadmium ,-,.., c	     3-64
          Cesium «.	     3-72
          Chromium	     3-77
          Columbium and Tantalum  	     3-80
          Gallium 	     3-88
          Germanium 	     3-93
          Gold and Silver 	:	    3-100
          Indium 	,	    3-116
          Iron and Steel 	    3-125
          Magnesium 	    3-136
          Manganese	   3-143
          Molybdenum  	   3-152
          Platinum Group Metals  	   3-158
          Rare Earth Metals  	   3-164
          Rhenium 	   3-175
          Rubidium 	   3-179
          Selenium 	   3-187
          Silicon and Ferrosilicon  	   3-194
          Strontium 	   3-198
          Tellurium 	   3-204
          Tin  	   3-211
          Titanium 	   3-217
          Tungsten 	   3-228
          Vanadium 	   3-245

                                      vi

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                              LIST OF FIGURES
Figure

2-1    Lithium Ore Processing 	     2-12
2-2    Lithium From Brines 	     2-13
2-3    Mica Processing by Washing 	     2-17
2-4    Mica Processing by Humphrey Spirals 	     2-18
2-5    Mica Processing by Acid-Cation from Froth Flotation 	     2-20
2-6    Mica Processing by Alkaline Anionic-Cationic Flotation 	     2-21
2-7    Perlite Processing 	     2-25
2-8    Potash Froth Flotation Processing 	     2-29
2-9    Potash Selective Dissolution 	     2-30
2-10   Potash Precipitation 	     2-31
2-11   Pumice Production 	     2-35
2-12   Trona Processing Wyoming Practice 	     2-44
2-13   Sodium Carbonate Processing, Searles Lake, California,
       Process 	     2-48
2-14   Sodium Sulfate Production, Ozark-Mahoning Process 	     2-49
2-15   Staurolite Production 	     2-53
2-16   Talc Processing 	     2-58
2-17   Vermiculite Processing 	     2-62
2-18   Barite from Residuum 	     2-66
2-19   Barite from Beds and Veins 	     2-67
2-20   Natural Asphalt Processing 	     2-71
2-21   Gilsonite Processing	     2-73
2-22   Mineral (Montan) Wax Production 	     2-75
2-23   Pyrobi tumen Processing 	     2-76
2-24   Borate Ore Processing, Boron, California  	     2-78
2-25   Borate Ore Processing, Death Valley, California 	     2-79
2-26   Borate Brine Processing, Searles Lake, California,
       Carbonate Process 	     2-81
2-27   Borate Brine Processing, Searles Lake, California,
       Evaporation Process 	     2-82
2-28   Boric Acid Production, Searles Lake, California 	     2-83
2-29   Bromine Extraction Processes	     2-86
2-30   Kaolin Processing Flowsheet  	     2-91
2-31   Beehive Coking Process 	     2-95
2^32   By-product Coking Process  	     2-97
2-33   Fluorspar Processing 	     2 -\06
2-34   Iodine Extraction 	     2-110
2-35   Kyanite Processing 	     2-114
2-36   Olivine Processing 	     2-117
2-37   Fluoride Pellet Phosphate General Flowsheet	    2-121
2-38   Intermountain Bedded Phosphate General Flowsheet  	     2-123
2-39   Phosphoric Acid Treatment  	    2-125
2-40   Elemental Phosphorous 	     2-126
2-41   Silica Production 	    2-129
2-42   Asbestos Processing 	    2-133
                                    vi i

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3-1    Cobalt Beneficiation from Lateritic Ore 	      3-5
3-2    Mercury 	     3-11
3-3    Nickel Ore Processing, Hanna,  Riddle,  Oregon 	     3-15
3-4    Scandium from Thortveitite #1  	     3-22
3-5    Scandium from Thortveitite #2  	,	     3-23
3-6    Scandium from Thortveitite #3  	     3-24
3-7    Scandium from Uranium 	     3-26
3-8    Beneficiation of Antimony Sulfide Ore by Flotation 	     3-32
3-9    Antimony Oxide Volatilization  Process 	     3-34
3-10   Antimony Smelting 	     3-35
3-11   Antimony Processing Liquidation Process 	     3-37
3-12   Antimony Iron Precipitation 	     3-38
3-13   Antimony Oxide Reduction Process 	     3-39
3-14   Antimony Reduction by Leaching and Electrolysis 	     3-41
3-15   Antimony Refining 	     3-42
3-16   Beryllium Extraction Processes at Brush Uellman, Delta,
       Utah Plant 	     3-49
3-17   Bismuth Copper Sources 	     3-55
3-18   Bismuth 3etterton-Kroll Process 	     3-56
3-19   Bismuth  Refining	     3-57
3-20   Bismuth Belts Electrolytic Extraction 	     3-59
3-21   Bismuth, Bismuth-Bearing Materials 	     3-61
3-22   High Cadmium Precipitate 	     3-66
3-23   Cadmium-Bearing Flue Dust 	     3-67
3-24   Cadmium Processing Alternative #1 & 2, Galvanic
       Precipitation with Zinc 	,.     3-68
3-25   Cadmium Processing Alternative #3,  Electrolysis 	     3-69
3-26   Cesium Recovery from Pollucite Ore 	     3-73
3-27   Columbium-Tantalum Processing 	     3-82
3-28   Process Flow Sheet for Gallium and Germanium Production ....     3-89
3-29   Recovery of Germanium During Zinc Ore Processing	     3-94
3-30   Process Flow Sheet for Gallium and Germanium Production ....     3-95
3-31   Processing of Crude Germanium 	 	     3-97
3-32   Gold-Silver Gravity/Amalgamation 	    3-103
3-33   Gold-Silver Leaching 	    3-105
3-34   Gold-Silver Agitation Leaching with Merrill-Crowe Recovery .    3-108
3-35   Gold-Silver Leaching, Carbon in Pulp versus Carbon in
       Leach	    3-110
3-36   Indium from Lead-Zinc Smelting Lead Chloride, Sodium
       Chloride, Zinc Chloride 	   3-118
3-37   Liberation of Indium from Lead 	   3-119
3-38   Indium Recovery from Cadmium-Bearing Fumes  	   3-121
3-39   Indium Recovery by Flue Dust Leaching  	   3-122
3-40   Iron and Steel General Process Flow Diagram  	   3-126
3-41   Iron and Steel Coal Preparation  	   3-130
3-42   Iron and Steel Coking	   3-131
3-43  . Mdgiiciaiuiii - Dow Electrolytic Process	   3-137
3-44   Magnesium - Amax Process  	   3-138
3-45   Magnesium - Silicothermic Process  	   3-139
                                     vn

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       Manganese Processing - Anaconda Process 	    3-145
       Manganese Processing - Dean-Leute Process 	    3-146
       Manganese Processing - Daugherty Process 	    3-147
       Manganese Processing - Welch Process 	    3-148
       Molybdenum Molybdenite Concentration (Climax Practice)  	    3-153
       Platinum Group Metal (PGM) Recovery from Copper Refining
       Slimes 	    3-160
3-52   Rare Earth Recovery from Monazite by the Sulfuric Acid
       Process 	    3-166
3-53   Production of Rare Earth Chlorides from Bastnaesite Ore ....    3-167
3-54   Rare Earth Separation by Solvent Extraction 	    3-170
3-55   Lanthanide Separation by Ion Exchange 	    3-171
3-56   Rhenium Recovery from Molybdenite Concentrate 	    3-176
3-57   Rubidium Alums Extraction 	    3-1BO
3-58   Rubidium Stannic Chloride Precipitation 	    3-182
3-59   Rubidium from Alkali Metals Reduction 	    3-183
3-60   Rubidium Reduction 	    3-184
3-61   Selenium Recovery from Copper Slimes by Soda Smelting 	    3-188
3-62   Selenium Recovery from Copper Slimes by Soda Roasting 	    3-189
3-63   Purification of Crude Selenium 	'	    3-191
3-64   Strontium Black Ash Process 	    3-200
3-65   Tellurium Recovery from Copper Slimes 	    3-205
3-66   Electrolytic Purification of Tellurium 	    3-206
3-67   Purification of Tellurium by Acid Precipitation 	    3-208
3-68   Tin Smelting 	    3-213
3-69   Titanium Beneficiation, New York Hardrock Ilmenite Deposits    3-218
3-70   Titanium Beneficiation Beach Sand Deposit 	    3-220
3-71   Titanium Processing Sulfate Process 	    3-221
3-72   Titanium Processing Chloride Process 	    3-223
3-73   Ti tanium Processing Kroll Process 	    3-224
3-74   Tungsten Processing Raw Ore 	    3-230
3-75   Tungsten Processing 	    3-232
3-76   Tungsten Processing Scheelite Acid Leaching 	    3-233
3-77   Tungsten Processing High Pressure Soda Process 	    3-234
3-78   Tungsten Processing Alkali Roasting Process 	    3-236
3-79   Tungsten Processing Liquid Ion Exchange Process 	    3-237
3-80   Tungsten Processing Sodium Tungstate Conversion 	    3-239
3-81   Tungsten Processing Reduction to Tungsten 	    3-240
3-82   Vanadium - Sodium Hexavanadate Production 	    3-246
3-83   Vanadium - Vanadium Pentoxide Products 	    3-247
3-84   Vanadium - Calcium Reduction 	   3-248
3-85   Vanadium - Aluminothermic Reduction 	   3-249
                                     IX

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                              LIST OF TABLES
Table                                                                  Page

ES-1  Nonmetal Industries 	   ES-3
ES-2  Metal Industries 	   ES-4
1-1   Nonmetal Industries 	    1-3
1-2   Metal Industries 	    1-4
2-1   Wastes from Lime, Limestone and Dolomite 	   2-10
2-2   Lithium Production Wastes 	   2-15
2-3   Mica Processing Wastes 	   2-22
2-4   Perlite Processing Wastes 	   2-27
2-5   Potash Processing Wastes 	   2-33
2-6   Wastes from Salt Production 	   2-38
2-7   Soda Ash Wastes 	   2-46
2-8   Sodium Sulfate Production Wastes 	   2-50
2-9   Vermiculite Processing 	   2-61
2-10  Barite Wastes 	   2-69
2-11  Borate Wastes 	   2-84
2-12  Bromine Production Wastes 	   2-88
2-13  Clay Wastes 	   2-92
2-14  Coal Wastes 	   2-99
2-15  Feldspar Processing Wastes 	  2-103
2-16  Fluorspar Wastes 	  2-108
2-17  Iodine Production Wastes 	  2-112
2-18  Kyanite Production 	  2-115
2-19  Olivine Production Wastes 	  2-119
2-20  Phosphate Processing Wastes 	  2-122
2-21  Silica 	  2-130
2-22  Asbestos Wastes 	  2-134
2-23  Shale Processing Wastes 	  2-136
3-1   Cobalt Beneficiation Wastes 	    3-6
3-2   Mercury Processing Wastes 	   3-12
3-3   Nickel Processing Wastes 	   3-18
3-4   Scandium Wastes 	   3-29
3-5   Antimony Processing Wastes 	   3-44
3-6   Beryllium Wastes 	   3-51
3-7   Bismuth Wastes 	   3-62
3-8   Cadmium Processing Wastes 	   3-70
3-9   Cesium Wastes 	   3-74
3-10  Chromium Wastes 	   3-79
3-11  Columbium, Tantalum Wastes 	   3-86
3-12  Gallium Wastes 	   3-91
3-13  Germanium Wastes	   3-98
3-14  Gold and Silver Wastes 	  3-114
3-15  Indium Processing Wastes 	  3-123
3-16  Iron and Steel W3.«?t«»<;	  3-134
3-17  Magnesium Wastes 	  3-141
3-18  Manganese Processing Waste 	  3-150
3-19  Molybdenum Wastes 	 3-156

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Table                                                                  Page

3-20  Platinum Group Metal Recovery Wastes 	  3-161
3-21  Rare Earth Metal Processing Wastes 	  3-173
3-22  Rhenium Wastes 	  3-177
3-23  Rubidium Wastes 	  3-185
3-24  Selenium Wastes 	  3-192
3-25  Silicon and Ferrosilicon	  3-196
3-26  Strontium Wastes 	  3-202
3-27  Tellurium 	  3-209
3-28  Tin Wastes 	  3-212
3-29  Titanium Processing Wastes 	  3-226
3-30  Common Approaches to Mineral Separation 	  3-229
3-31  Tungsten Processing Wastes 	  3-242
3-32  Vanadium Wastes 	  3-251
                                    xi

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                             EXECUTIVE SUMMARY

This document is a compilation of draft reports on the processes used to
recover mineral or metal commodities from ores and concentrates and wastes
generated during processing of these commodities.   These reports were
prepared as a part of the engineering and technical support efforts to
EPA's Subtitle D Mining Waste Regulatory Development Programs.

Processing waste summaries were prepared as part of the supporting
documentation for the Second Report to Congress on Solid Waste From
Selected Metallic Ore Processing Operations (RTC II).  These summaries were
based on brief reviews of readily available literature, and are the first
stage in the scoping of the Third Report to Congress (RTC III) which will
address all industries not included in the first two Reports to Congress.
Each industry summary discusses production, processing methods, waste
generation, and waste management for a commodity or related group of
commodities.  These summaries include those commodities or stages of
production not addressed in RTC I or RTC II.  Tables ESI and ES2 list which
commodities are included in each report.  Each summary evaluates the
potential for the generation of hazardous waste in the production and
processing of each commodity.

Based on the commodity evaluation, recommendations are made for further
study of those industries that show a potential for hazardous waste
generation and potential Subtitle C regulation.  Industries that show no
potential for hazardous waste generation are not recommended for further
study.

A comprehensive list of commodities produced in the U.S. from mineral
resources in 1987 was developed based on previous EPA  lists, U.S.  Bureau  of
Mines publications, and industry literature.  This list was reviewed  bv  the
                                   ES-1

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EPA and U.S. Bureau of Mines and the updated list was divided into nonmetal
and metal commodities.  Tables ES-1 and ES-2 show in which Report to
Congress each of the commodities is addressed.

Processing wastes summary reports were prepared for nonmetal and metal
commodities and submitted to the EPA and the Bureau of Mines for comment in
1987.  Revisions were made to the processing waste summary reports and the
reports were resubmitted to EPA and the Bureau of Mines for further review.
One paragraph summaries of these revised reports were prepared for RTC II
in August 1987.  Further study is recommended for the industries producing
     *
18 nonmetal commodities and 27 metal commodities.

The primary reasons for recommending further study of these industries is a
lack of information on waste production and waste characteristics.  These
are not necessarily recommendations for regulation under Subtitle C,
although some waste streams may require such controls.  More detailed study
is needed before a regulatory recommendation can be made.  The
recommendations here can be used as a guide to how resources can be best
used in developing future regulations.

There are some industries that are not addressed here that are in early
stages of development and may become major waste generators in the future.
The most notable industry in this class is oil shale.  Platinum group metal
processing might start in this country in the next 5  to 10 years, and
nickel processing could also restart production.  Due to  the rapid
technological changes that can be expected of developing  industries, study
of current proposals may give little information on  future waste
generation. Studies on these industries should be deferred until specific
processes have been selected and tested, at which time waste
characteristics can be accurately determined.
                                   ES-2

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                                TABLE ES-1

                            NONMETAL INDUSTRIES
                    RTC I
                   E and B*
 RTC II
Process
RTC III
E and B*
                                                       Process
Oil Shale
olivine
Peat
PerUte
Phosphate
Potash
Pyrobitumena
Fyrophyllite
Salt
Sand t Gravel
Silica
Soda Ash
Sodium Sulfate
Staurolite
Stone
Sulfur
Talc
Tripoli
Vermiculite
Wollastonite
               X
               0
               0

               0
               X
               o
               0
               o
               X
               o
               0
               o
               o
               o
               o
               o
               0
               o
               X
               0
               0
               X
               0
               X
               o
               0
               o
               X
               0
               o
               o
               0
               o
               o
               0
               0
               o
                                                                   Comments
Natural Asphalt
Batite
Boron -
Bromine
Clay
Coal
Diatomite
Feldspar -
Fluorh^ar -
Garnet
Gemstonea
Gilsonite
Olauconlte
Gypsum
Iodine
Kyanite
Limestone
Lithium
Mica
Mineral Waxes
o
X
X
X
X
X
o
X
X
0
0
X
o
o
X
X
0
o
o
X
0
X
X
X
X
X Note c
O
X
X
o
o
X
0
o
X
X
O Note d
0
0
X
                                                                   Note e
0  Screened for RTC III tout no further study recommended.
X  Studied or recommended for study under appropriate RTC.

a  Extraction and Beneficiation
b  Processing
c  Beneficiation, Gasificeation, Coking
d  Cement Processing in Report to Congress for RCRA 8002(o)
e  Oil Shale Extraction, Benefieiation, and Processing addressed in RTC I
                                 ES-3

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                               TABLE ES-2

                            METAL  INDUSTRIES
Commodity
Aluminum
Antimony
Arsenic
Beryllium
Bismuth
Cadmium
Cesium
Chroraiun
Cobalt
Columbium I
Tantalum
Copper
Gallium
Germanium
Gold t Silver
Indium
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Platinum
Rare Earths
Rhenium
Rubidium
Scandium
Selenium
Silicon
Strontium
Tellurium
Tin
Titanium
Tungsten
Vanadiun
Zinc
Zinc oxide
Zirconium 4
Hafnium
RTC I
E and B
X
X
-
X
_

-
_
-

-
X
-
-
X
-'
X
X
-
'
X
X
X
X
X
-
-
-
X
-
-
-
-
X
X
X
X
X

~
RTC II. RTC Ii:
b a
Process E and B
X
-
-
-
—
-
-
-
-

-
X
- -
-
-
-
-
X
-
-
-
-
-
- -
-
-
-
-
-
-
-
- -
-
-
-
-
X
X

"™ ~
RTC III
Process
_
X
o
X
X
X
X
X
o

X
X
X
X
X
X
X
-
X
X
o
X
o
0
X
X
X
0
X
X
X
X
X
X
X
X
-
-

X
Comments


Note c

Note c
Note c
Note d
Note d
Note d

Note c

Note e
Note e

Note c


Note f
Note d





Note c

Note c

Note g
Note d
Note c
Note d






Note c
O  Screened for RTC III but no further study recommended.
X  Studied or recommended for study under appropriate RTC.

a  Extraction and Beneficiation
b  Processing
c  Produced from materials that are by-products of beneficiation or
   processing of other metals
d  Produced froa imported ores or concentrates
e  Predominantly produced as by-products, one new mine produces Gallium and
   Germanium as primary products
f  Produced from either brines needing no extraction or beneficiation or
   from dolomite which is covered elsewhere
g  Silicon is mad* from Silica (covered as a nonmetal); Ferrosilicon may
   use some iron ore in addition to silica sources
                               ES-4

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                             1.0  INTRODUCTION

1.1  STATUTORY AND REGULATORY BACKGROUND

Sections 8002(f) and (p) of the Resource, Conservation and Recovery Act
(RCRA) (Solid and Hazardous Waste Amendments of 1984), require EPA to
conduct a study of mining wastes.  Congress prohibited EPA from regulating
mining wastes under Subtitle C (hazardous wastes) until at least six months
after issuing the mining waste study (RCRA Section 3001(b)(3)(a)(ii)).   On
December 31, 1985, the Agency submitted its First Report to Congress (RTC
I) on wastes generated from the extraction and beneficiation of metallic
ores, phosphate rock, asbestos, overburden from uranium mining, and oil
shale.  Based on RTC I and comments received after issuance of the report,
EPA published its "regulatory determination" on July 3, 1986 as required by
RCRA 3001(b)(3)(c).  EPA's determination stated the Agency's intent to
regulate, under Subtitle D (solid waste), the large volumes of waste
generated by the mining industry.

The Agency is planning to issue in 1988 a Second Report to Congress (RTC
II) on wastes generated by copper, lead, zinc and zinc oxide, bauxite,  and
aluminum ore processing operations.  EPA will issue a regulatory
determination on these processing wastes subsequent to receipt of comments
on RTC II.  A Third Report to Congress (RTC III) on remaining mining and
processing sectors has also been proposed but not yet fully funded.

1.2  PURPOSE OF THIS REPORT

The processing waste summaries in Sections 2 and 3 of  this report were
prepared as part of the supporting documentation for  RTC  II.  These
summaries were based on brief reviews of readily available literature, and
are the first stage in the scoping of RTC III.  Each  industry  summary
discusses production, processing methods, waste generation, and waste
manager.ent for a commodity or related group of commodities.  These
                                   1-1

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summaries address those commodities or stages of production not addressed
in RTC I or RTC II.  Tables 1-1 and 1-2 list which commodities are included
in each report.  Each summary evaluates the potential for the generation of
hazardous waste in the production and processing of each commodity.

Based on the commodity evaluation, recommendations are made for further
study of those industries that show a potential for hazardous waste
generation and potential Subtitle C regulation.  Industries that show no
potential for hazardous waste generation are not recommended for further
study.

1.3  PREPARATION OF THE PROCESSING VASTE SUMMARIES

A comprehensive list of commodities produced in the U.S. from mineral
resources in 1987 was developed based on previous EPA lists, U.S. Bureau of
Mines publications, and industry literature.  This list was reviewed by  the
EPA and U.S. Bureau of Mines and the updated list was divided into nonmetal
and metal commodities.  Tables 1-1 and 1-2 show in which Report to Congress
each of the commodities is addressed.

Processing wastes summary reports were prepared for nonmetal and metal
commodities and submitted to the EPA and the Bureau of Mines for comment in
1987.  Revisions were made to the processing waste summary reports and  the
reports were resubmitted to EPA and the Bureau of Mines for further review.
One paragraph summaries of these revised reports were prepared  for RTC  II
in August 1987.  The one paragraph summaries are listed in Section 1.5.

1.4  SUMMARY AND CONCLUSIONS

This document contains process descriptions  for 74 commodities  produced in
the U.S. from mineral sources, 42 of which are nonmetals and 32 are metals.
Further study for possible regulation under  Subtitle C  is not  recommended
for 24 nonmetal commodities and 5 metal commodities.  Some of  the
industries generate no waste, some generate  waste with  no hazardous
                                   1-2

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              TABLE  1-1

         NONHETAL INDUSTRIES
 RTC I
E and 3°
 RTC II
Process
RTr III
E end B"
RTC III
Process
                                               Comments
Natural Asphalt
Barite
Boron
Bromine
Clay
Coal
Diatomite
Feldspar
Fluorspar
Garnet
Gemstones
Cilsonite
Glauconite
Gypsum
Iodine
Kyanite
Limestone
Lithium
Mica
Mineral Waxes
Oil Shale
Olivine
Peat
Perlite
Phosphate
Potash
Pyrobitumens
Pyrophyllite
Salt
Sand 4 Oravel
Silica
Soda Ash
Sodium Sulfate
Staurolite
Stone
Sulfur
Talc
Tripoli
Vermiculite
Wollastonite
O Screened for RTC
_ _
- -
-
_
- . •
- -
-
-
-
- -
-
-
-
-
- -
-
-
-
_ _
-
X
_
-
-
X
-
-
-
- -
.
-
_ _
-
-
-
-
-
-
-
- -
III but no further study
0
X
X
X
X
X
0
X
X
0
0
X
0
0
X
X
0
O
0
X
-
X
O
O
-
0
X
O
O
O
X
O
O
O
O
O
O
0
O
O
recommended.
0
X
X
X
X
X
0
X
X
0
0
X
0
0
X
X
O
0
0
X
.
X
0
0
X
0
X
O
0
O
X
O
O
O
O
0
O
0
O
O






Note c










Note d



Note e




















X Studied or recommended for study under appropriate RTC.
a Extraction and Beneficiation
b Processing




c Beneficiation, Gasif iceation, Cokinq
d Cement Processinq
in Report to Conqreis for RCRA 8002(0)
e Oil Shale Extraction, Beneficiation, and
Processinq addressed
in RTC I
            1-3

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                                 TABLE  1-2

                             METAL INDUSTRIES
Commodity
Aluminum
Antimony
Arsenic
Beryllium
Bismuth
Cadmium
Cesium
Chromium
Cobalt
Columbium i
Tantalum
Copper
Gallium
Germanium
Gold i Silver
Indium
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Platinum
Rare Earths
Rhenium
Rubidium
Scandium
Selenium
Silicon
Strontium
Tellurium
Tin
Titanium
Tungsten
Vanadium
Zinc
Zinc Oxide
Zirconium t
Hafnium
RTC I
E and B*
X
X
-
X
-
-
-
-
-

-
X
-
-
X
-
X
X
-
-
X
X
X
X
X
-
-
-
X
-
-
-
-
X
X
X
X
X

—
RTC II
Process
X
-
-
-
-
-
-
-
-

-
X
-
-
-
-
-
X
-
-
-
-
-
-
-
-
-
-
1
-
-
-
-
-
-
-
X
X

~
RTC III
E and B*
_
-
-
-
-
-
-
-
-

-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
.
-
-
-
-
-
-
-
-
-
-
-

—
RTC III
Process
.
X
0
X
X
X
X
X
o

X
X
X
X
X
X
X
-
X
X
o
X
0
o
X
X
X
o
X
X
X
X
X
X
X
X
_
-

X
Comments


Note c

Not* c
Note c
Note d
Note d
Note d

Note c

Note e
Note e

Note c


Note f
Note d





Note c

Note c

Note g
Note d
Note c
Note d






Note c
O  screened for RTC III but no further study recommended.
X  Studied or recommended for study under appropriate RTC.

a  Extraction and Beneficiation
b  Processing
c  Produced from materials that are by-products of beneficiation or
   processing of other metals
d  Produced from imported ores or concentrates
e  Predominantly produced as by-products, one new mine produces Gallium and
   Germanium as primary products
f  Produced from either brines needing no extraction or beneficiation or
   from dolomite which is covered elsewhere
g  Silicon is made from Silica (covered as a nonmetal); Ferrosilicon may
   use some iron ore in addition to silica sources
                                1-4

-------
characteristics, some industries.are too small to generate wastes in
sufficient volume  to require regulation, and other industries have
recently shut down permanently.

Further study is recommended for the industries producing 18 nonmetal
commodities and 27 metal commodities.

The primary reasons for recommending further study of these industries is a
lack of information on waste production and waste characteristics.  These
are not necessarily recommendations for regulation under Subtitle C,
although some waste streams may require such controls.  More detailed study
is needed before a regulatory recommendation can be made.  The
recommendations here can be used as a guide to where resources can be best
used in developing future regulations.

There are some industries that are not addressed here that are in early
stages of development and may become major waste generators in the future.
The most notable industry in this class is oil shale.  Platinum group metal
processing might start in this country in the next 5 to 10 years and nickel
processing could also restart production.  Due to the rapid technological
changes that can be expected of developing industries, study of current
proposals may give little information on future waste generation. Studies
on these industries should be deferred until specific concrete processes
have been selected and tested at which time waste characteristics can be
accurately determined.

The following one paragraph summaries are reproduced here  from RTC II,
Chapter 2.0.  They are presented in order that the reader  may preview  the
scope of future investigations in the possible generation  of  hazardous
waste by the mining industry.  They are divided  into  four  sections:

     •  nonmetals not recommended for further study
     •  nonmetals recommended for further study
     •  metals not recommended for further study
                                   1-5

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     •  metals recommended for further study

The reader should be aware that some commodities that are given separate
summaries in this section are combined with closely related commodities in
the more detailed reports in Sections 2 and 3.   For example, zirconium and
hafnium are addressed in Section 3 by the report entitled "Rare Earth
Metals" since they are produced from the same feedstocks.

1.4.1  Nonmetals Not Recommended for Further Study

Diatomite - Diatomite is selectively mined to eliminate waste materials.
The diatomite is dried and separated into size fractions, which are sold as
products.  Any material that is too fine for sale is sintered into coarser
particles.  This processing does not generate hazardous wastes.

Garnet - Garnet materials are quarried and the garnets separated using a
variety of techniques, including density separation, magnetic separation,
and flotation.  Garnet processing processing uses no hazardous materials,
and wastes are not expected to be hazardous.
                                                  \
Gems tones - The gem industry in the U.S. is extremely small as a whole, and
each operation producing gemstones is also quite small.  Much production
will be on hand and as a by-product of printing or quarrying other
materials.  The gemstone industry therefore is not expected to produce
significant quantities of hazardous waste.

Glauconite - Glauconite, also known as green sand, is mined hydraulically
and piped to a processing plant where clays and other undesirable materials
are washed out.  The glauconite is then  treated with chemicals such as
sodium aluminate, aluminum sulfate, or sodium silicate,  to  give  it ion
exchange properties for use in water softening.  No hazardous wastes  are
expected from this processing.
                                   1-6

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Gypsum - Natural gypsum is selectively mined so that there is little or no
waste.  Mined gypsum needs no beneficiation.  Some gypsum is processed by
calcination for use in gypsum board (wallboard),  gypsum plaster,  and gypsum
cement.  Calcined gypsum is not hazardous, and all of it can be used in
some product.  No hazardous vastes are expected from gypsum processing.

Lime, Limestone, and Dolomite - Limestone and dolomite are produced by
selective mining which generates a very small amount of non-hazardous
waste.  Preparation for market is limited to crushing and screening
operations, which generate no wastes.  There is nothing associated with
limestone or dolomite deposits that would be hazardous even if discarded.
Lime is produced from limestone or dolomite by heating to high temperature
to drive off carbon dioxide, leaving calcium oxide or calcium oxide and
magnesium oxide.  Since all solids are contained in some product, no solid
wastes are normally generated during lime processing.

Lithium - Lithium and lithium compounds are produced from the mineral
spodumene and from brines. Spodumene is concentrated from pegmatite ores  by
froth flotation.  The waste materials from froth flotation are
non-hazardous silicate minerals.  Flotation chemicals that might remain  in
the wastewaters would not render that water hazardous.  Lithium carbonate
is produced by acid leaching of heat treated spodumene.  Since the acid  is
neutralized with limestone during the process, the residual calcium sulfate
(gypsum) sludge is not expected to be hazardous.  Lithium carbonate is
precipitated from concentrated brines by  the addition of soda ash.  No
hazardous wastes are expected from this treatment.

Mica - Mica is mined from pegmatite deposits and concentrated primarily  by
flotation.  The silicate minerals in the  pegmatite wastes and  the  flotation
reagents in the wastes are not expected to be hazardous.

Peat - Peat is primarily used in agricultural and horticultural
applications.  Peat is used as mined, and nc significant wastes are
expected from peat production.
                                   1-7

-------
Perlite - Perilte is selectively mined, processed by screening to remove
waste rock, and then expanded by heating.   The waste rock is not expected
to be hazardous.
Potash - Potash is produced by conventional mining,  solution mining,  and
treatment of natural subterranean brines.  Conventionally mined ores  are
treated by froth flotation which generates non-hazardous tailings
containing halite (common salt) and some silicate minerals.   Potash brines
are generally evaporated and selectively precipitated.   One operation uses
froth flotation to separate the salts precipitated during solar
evaporation.  The wastes from this process are brine and salts such as
sodium chloride, and are not expected to be hazardous.

Pumice - Pumice is a volcanic rock which is selectively mined to eliminate
undesirable material, then processed by size reduction and size sorting
only.  No hazardous wastes are expected from pumice processing.

Pyrophyllite - Pyrophyllite is a talc-like mineral that is produced by
selective mining, and is processed by grinding to meet size specifications.
No hazardous wastes are expected from pyrophyllite production or
processing.

Salt and Rock Salt (Halite) - Rock salt, used for road deicing and other
applications where purity is not a prime requirement, is selectively mined,
crushed and sorted by size.  No hazardous wastes are expected.  Some salt
is solution mined, yielding a brine from vhich the salt is precipitated.
Solution mining and solar extraction of lake brines and seawater produce
waste salts and brines that are discarded.  These salts and brines are
primarily calcium and magnesium salts and are not expected  to be hazardous.

Sand and Gravel and Crushed Stone - Sand and gravel are mined and  processed
by washing, drying, and sorting by size.  The only wastes from processing
sand and gravel are fine materials such as clay and silt  that are  washed
                                   1-8

-------
away in processing.  These materials are not expected to exhibit  hazardous
characteristics.  Crushed stone production only generates fugitive dust
releases with all of the crushed rock being used as product.   The fugitive
dusts are not expected to be hazardous.

Soda Ash - Soda ash is produced from the mineral trona by conventional
underground mining and solution mining,  and also from naturally occurring
brines.  Trona that has been conventionally mined is processed first by
calcination, which generates wastes of carbon dioxide and water.   The
calcined.material is then dissolved in water.  Insoluble materials such as
shale are separated by settling and/or filtration,  and are discarded as
non-hazardous wastes.  the sodium carbonate solution is concentrated by
evaporation and crystallized into either the monohydrate or sesquihydrate
form.  The precipitate can be sold or the sesquihydrate form may be
calcined to produce another product.  No hazardous  wastes are expected from
the concentration, crystallization, or calcination  steps.  Solution mined
trona undergoes similar processing and yields similar wastes.  Natural
brines in California containing sodium carbonate are treated with carbon
dioxide to convert the sodium carbonate to bicarbonate, which then
precipitates.  The bicarbonate is separated from the remaining brine by
settling and filtration.  The brine is processed further, and the sodium
bicarbonate is calcined to convert it back to soda  ash, releasing carbon
dioxide and water.  The only waste from this process would be the final
discarded brine, which is not expected to be hazardous.

Sodium Sulfate - Sodium sulfate is produced from brines at Searles  Lake,
California, Great Salt Lake, Utah, and in Vest Texas.  The Vest Texas
brines are treated by refrigeration to 40°F, precipitating a hydrated  form
of sodium sulfate which is treated in mechanical vapor recompression
crystallizers to drive off the water of hydration and produce anhydrous
sodium sulfate.  The only waste is the treated brine, which  is not  expected
to be hazardous.  Sodium sulfate is produced in a similar manner  from  lake
brines.  At the Great Salt Lake, solar evaporation  is used to concentrate
the brines and to precipitate sodium chloride, which is harvested and  sold.
                                   1-9

-------
Winter weather is allowed to cool the brine from which Glauber's salt
precipitates; the salt is harvested using earth moving equipment.   At
Searles Lake, California sodium sulfate is extracted from the top layer of
brine.  Borax is crystallized by cooling and removed as a product.   Further
cooling to 40°F causes precipitation of Glauber's salt, which is removed by
filtration, purified, and dehydrated as above.   The only wastes produced
are spent brines, which are not expected to be  hazardous.

Staurolite - Staurolite is produced as a by-product of beach sand mining
for titanium.  Staurolite is separated from titanium minerals by high-
tension separators, then magnetically separated from other silicate
minerals.  The silicate minerals are discarded  as waste, but they are not
hazardous.

Stone (Building) - Building stone is defined, for the purposes of this
report, as all stone used in construction exclusive of aggregates used in
concrete or asphalt.  This includes both structural and ornamental stone.
These materials are produced by selective mining or cutting, and are
processed by crushing, cutting, and/or polishing.  The wastes from any of
these operations are negligible in volume and not expected to be hazardous.

Sulfur - The major production of sulfur involves recovery of sulfur from
air pollution control systems.  This is not a mineral source and will not
be addressed in this study.  However, 42X of the sulfur in the U.S. is
produced by the Frasch process from salt domes.  In this process, hot water
is injected into the sulfur-bearing layers of the formation.  The hot water
melts the sulfur, which is pumped to the surface.  Waste water  is collected
from wells at the periphery of the salt dome, treated, and released.  This
waste water is not expected to be hazardous.  Sulfur  is also produced by
roasting (burning) iron pyrite to produce sulfur dioxide gas and iron oxide
solid.  The gas can be treated to generate either elemental sulfur or
sulfuric acid.  Neither treatment produces significant amounts  of waste,
leaving the iron oxide as the only waste from pyrite  processing,  it  is  not
expected to be hazardous.
                                   1-10

-------
Talc - Talc processing may be as simple as selective mining or involve
complex processes such as froth flotation.  Wastes are primarily accessory
minerals and limestone or dolomite which are not hazardous and accessory
minerals which may be asbestiform.

Tripoli - Tripoli is a fine grained form of silica used in abrasives,
buffing, and polishing compounds.   Mining is by open cut or underground
room and pillar methods.  The open cut method may produce some mine waste,
which is not expected to be hazardous.  Processing consists of crushing,
drying, and grinding.  With the exception of moisture loss, all of the ore
is in the product, leaving no wastes.

Vermiculite - Vermiculite is a mica-like mineral that expands vhen heated.
Processing consists of removal of waste rock by screening and expansion.
The waste rock is not expected to be hazardous.

Wollastonite - Uollastonite is a calcium silicate used primarily as a
filler.  Selective mining produces an ore containing few impurities.  Any
mining waste would not be expected to be hazardous.  Processing consists of
crushing and screening into product size fractions.  One plant uses
magnetic separators to recover garnet and diopside by-products which would
not be hazardous if discarded.

1.4.2  Nonmetals Recommended for Further Study

Barite - Barium is the element found  in barite, and  is one of  the  eight
metals for which there are concentration criteria in the specification  for
the EP-toxicity test, and the test extractant  is expected  to  leach barium
from barite.  The unavoidable residuals of barite in the processing waste
may result in the wastes failing the  EP-toxicity test.
                                   1-11

-------
Bituminous Materials - The four segments of the bituminous materials
industry (natural asphalts, gilsonite, mineral wastes and pyrobitumens) are
addressed separately belov.

    Natural Asphalt - No study is planned because no hazardous wastes are
    expected to be produced.
    Gilsonite - Gilsonite dust generated in handling and processing is
    potentially ignitable.  The amounts and management practices of these
    wastes are not currently documented in the literature, so further study
    is recommended.
    Mineral Uaxes - Solvent extraction is used to produce these materials.
    The solvents were not identified in the literature reviewed.  Since
    these solvents could be listed substances in 40 CFR 261 Subpart D, the
    identities, volumes and management practices of spent solvents need
    characterization.
    Pyro-bitumens - These are also processed by solvent extraction and need
    the same characterization as for mineral waxes.
Boron and Borates - The primary area of concern is the production of boron
compounds from desert lake brines.  The spent brines may exhibit hazardous
characteristics.  The nature and management of the brines needs more
characterization.

Bromine - Bromine is a reactive material and many bromine compounds will
exhibit hazardous characteristics.  Chlorine is used in bromine extraction.
The nature and management practices of wastes from bromine production are
not fully described in available literature.

Clays - Some kaolin clay is subjected to bleaching processes that use
hazardous materials such as strong acids combined with reducing agents  or
oxidizing agents such as chlorine or ozone, which could result in wastes  -
from bleaching exhibiting hazardous characteristics.  The nature and
management practices of these bleaching wastes are not described in  the
available literature.
                                   1-12

-------
Coal - The coal industry sectors included in the scoping process were
beneficiation, liquefaction, gasification, and coking.   No further study of
coal liquefaction is recommended since there are no commercial operations.
Further study of beneficiation is recommended because of the acid
generation potential of coal cleaning refuse.  Gasification, as performed
by American Natural Gas in Beulah, North Dakota, is recommended for study
due to the production of reactive (hydrogen sulfide generating) wastes and
the possibility of listed solvents as wastes.  Coking produces a number of
potentially hazardous by-products, such as ignitable materials and organic
solvents.  While these may be burned in the process or sold for processing,
some may end up as wastes.

Feldspar - Potentially hazardous materials are used in the froth flotation
processing of feldspar.  These materials could result in tailings that
exhibit hazardous characteristics.

Fluorspar - Fluorite tailings could exhibit fluoride problems and toxicity
due to metals associated with the ore.  The nature of and management
practices for fluorspar tailings should be further characterized.

Iodine - Iodine is a reactive material and some iodine compounds exhibit
hazardous characteristics.  Chlorine is used in iodine production.  The
nature and management practices of iodine production wastes are not fully
described in available literature.

Kyanite - Tailings from kyanite processing contain iron sulfides  that  may
generate acid mine drainage when oxidized.  The waste may generate hydrogen
sulfide if it is exposed to acids, and thus could be reactive.  Both
situations could result in the tailings exhibiting hazardous
characteristics.

Olivine - Lead and chrome bearing minerals are associated with  some  olivine
deposit's.  There may HP pnougb i.pad and chrome content  to cause,  tailings to
fail the EP-toxicity test.  The volumes, nature, and management  practices
of these wastes need to be defined.
                                   1-13

-------
Phosphate Rock. Phosphoric Acid, and Elemental Phosphorous - The large
volume of waste generated by this industry (over 400 million tons per
year), and the radioactive nature of some wastes (particularly
phosphogypsum from phosphoric acid production) are the primary reasons for
studying this industry.  Other areas of concern include fluorine emissions
ana the possible generation of corrosive wastes in the phosphoric acid
industry.

Silica Sand - The froth flotation process used to upgrade silica sand is
carried out at low pH (between 2 and 3) and tailings could exhibit
corrosive characteristics (ph <2).  The actual pH, volume, and management
practices for these wastes need to be determined.

Other commodities are included here that may require further study.

Asbestos is a material that could be hazardous, but is not currently
regulated by RCRA and therefore not included in 8002(p) studies.  A policy
decision by the EPA will determine the probable regulatory status of  this
industry.

Shale used in making lightweight aggregate is  the other commodity needing
further clarification.  Wastes from lightweight aggregate production  are
not expected to exhibit hazardous characteristics.  However, in some  shale
popping operations, thermal processing uses listed wastes as fuels.   The
question to be addressed is whether shale fines from kilns fired with
listed wastes are to be considered hazardous under the "waste derived from
a listed waste" requirement of 40 CFR 261.

1.4.3  Metals Not Recommended for Further Study

Arsenic - Primary production of arsenic and arsenic compounds has  recently
ceased in the United States.  Demand is being  met by imports.
                                   1-14

-------
Cobalt - The only primary cobalt refinery in the U.S.  closed permanently in
1985.  The plant is now reprocessing other materials.

Mercury - Primary mercury production is confined to one mine in Nevada.   No
hazardous wastes are expected from processing.

Nickel - The only nickel mine in the United States closed in 1986 and the
plant was listed for sale by a used equipment dealer in 1987.   All other
production is a by-product of copper refining,  and is  not expected to
generate wastes with hazardous characteristics.

Platinum Group Metals - There is one mine producing platinum group metals
in the United States.  This mine went into production  in 1987.' The ore
from the mine is shipped to Belgium for processing.  Because the only
processing of platinum in the U.S. is from secondary sources,  platinum is
not recommended for further study.

Scandium - Scandium is produced by only one plant at such a small rate that
the wastes produced would probably fall under the small quantity generator
limits of Subtitle C.

1.4.4  Metals Recommended for Further Study

Antimony - A large portion of antimony production is a by-product of
lead-silver processing.  Further study is recommended because of wastes
that may be reactive (due to sulfide generation), corrosive, or contain
toxic metals.

Beryllium - Beryllium processing uses strong acids and other potentially
hazardous materials that may render wastes  from such processing corrosive.

Bismuth - All bismuth production is from  intermediate metallurgical
products such as lead bullion.  Most materials generated  in bismuth
                                   1-15

-------
extraction are products or are recycled.  However,  acids are used and if
some products are discarded they may be toxic.

Cadmium - Cadmium is one of the eight EP-toxic test metals.   Residues from
processing could contain toxic levels of cadmium and other metals.
Corrosive wastes may also be generated.  Cadmium is produced as a
by-product of zinc processing.

Cesium - Cesium is produced by one firm from imported ore.  The processing
uses strong acids that could generate corrosive wastes.  Contaminant metals
could cause wastes to be toxic.

Chromium - All chromium products are made from imported or secondary
materials.  Wastes, if any, from chromite refractory manufacturing and
chromium chemical production may be EP-toxic.

Columbium and Tantalum - These metals are produced together exclusively
from imported and secondary materials.  Processing to extract columbium and
tantalum uses strong acids and solvent extraction.   Wastes may be corrosive
or contain toxic metals, and waste solvents may be ignicable.

Gallium - Gallium is co-produced as a primary product with germanium at one
plant.  Another facility produces gallium from imported materials and
scrap.  Gallium processing uses acid leaching and solvent extraction.
Wastes from the leaching may be corrosive and waste solvent may  be
ignitable.

Germanium - Germanium is co-produced as a primary product with gallium  at
one plant.  Other plants extract germanium from secondary materials  and as
a by-product of other metal processing.  Germanium production uses strong
acids which may generate corrosive wastes.  Residues from production as a
by-product may contain toxic metals.
                                   1-16

-------
Gold and Silver - The cause of most health or environmental public concern
in gold and silver production is the use of cyanide in leaching,  which may
generate reactive wastes.  Silver is one of the eight EP-toxicity test
metals and residual amounts left after processing may cause wastes to be
EP-toxic.  Strong acids used in precious metal refining may generate
corrosive wastes.

Indium - Indium is produced from residues (primarily flue dusts)  of 2inc
and other base metal production.  The wastes from this processing may
contain toxic metals.  Acid leaching is also used, which may cause wastes
to be corrosive.

Iron - This industry has undergone and continues to undergo a very large
contraction.  Despite this, the industry remains one of the largest
addressed in these studies.  Flue dusts, used refractory materials, and
slags may contain toxic metals.  Coke-making wastes may be ignitable or
contain cyanides and listed organic wastes.

Magnesium - Magnesium is produced from sea water, from brines of  the Great
Salt Lake, and from dolomite.  Processing uses strong acids which may
generate corrosive wastes.

Manganese - All manganese raw materials are imported.  Manganese  dioxide
production may generate corrosive wastes.  Manganese alloy production may
produce flue dusts that contain toxic metals.

Molybdenum - Molybdenum is produced both as a primary product and as  a
co-product with copper.  Flue dusts from molybdenite  roasting may contain
toxic metals and there may be corrosive wastes from chemical production.

Rare Earth Hetals - Some rare earth metals are produced as by-products  of
titanium and zirconium extraction.  Thorium and yttrium are by-products of
rare earth metal production.  The separation of rare  earth metals from  each
                                   1-17

-------
other uses acid leaching and solvent extraction.   The leaching wastes may
be corrosive, and waste solvents may be ignitable or listed.

Rhenium - Rhenium is produced as a by-product of  the roasting of molybdenum
concentrates that come from porphyry copper deposits in the southwestern
United States.  Rhenium processing uses acid leaching and solvent
extraction.  Leaching residues may contain toxic  metals,  wastes may be
corrosive, and solvent extraction wastes may be ignitable or listed.

Rubidium - Rubidium is produced by one domestic company from imported ore.
Processing uses strong acids and solvents extraction with the possibility
of corrosive and ignitable or listed wastes.

Selenium - Selenium is primarily recovered as a by-product of copper
electro-refining.  Some may be produced from lead electro-refining slimes
and flue dusts.  Acids are used in processing, possibly generating
corrosive wastes.  Selenium is one of the eight metals monitored in  the
EP-toxicity tests.  Wastes from selenium processing may be toxic.

Silicon - Most silicon is used for alloying in the steel and aluminum
industries.  A very small amount of highly purified material is used in
electronics.  Flue dusts from the electric arc furnace production of
silicon metal or ferrosilicon alloy may contain toxic metals.

Strontium - Strontium materials are produced from imported ores.  The
processing of strontium ores uses strong acids that may generate corrosive
wastes.  The residues from strontium processing may contain  toxic metals.

Tellurium - Tellurium is a by-product from one plant refining  copper by
electrolysis.  Processing to extract tellurium uses strong acids which
may generate corrosive wastes.  Residual materials  from  tellurium
extraction may contain toxic metals.
                                   1-18

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Tin - There is one tin smelter in the United States produces tin from
mostly imported ore and secondary materials.  Previous investigation by EPA
identified EP-toxic wastes.

Titanium - The production of titanium uses strong acids which may have some
wastes corrosive.  Residual materials have, been shown to be corrosive, and
may contain toxic metals.

Tungsten - Tungsten production uses acid leaching and solvent extraction.
Corrosive, ignitable and listed wastes may be generated.  The residual
materials may contain toxic metals.

Vanadium - Vanadium is produced as a by-product of phosphorous and uranium
mined in the western intermountain region of the U.S.  Acid leaching and
solvent extraction may generate corrosive, ignitable, and listed wastes.
Vanadium alloy production may generate residues containing  toxic metals.

Zirconium and Hafnium - Zirconium and hafnium are produced  from zircon
concentrates.  These concentrates are co-products of titanium production
from beach sand deposits.  The processing of zirconium and  hafnium uses
strong acids which may make wastes corrosive.  Residual materials may
contain toxic metals.

1.5  REFERENCES

The descriptions in Sections 2.0 and 2.3 all use the following  six basic
references, and others as noted:
Lefond, Stanley J.  1983.  Industrial Minerals and Rocks, 5th edition,
     published by the Society of Mining Engineers of AIME.
U.S. Bureau of Mines.  1985.  Mineral Facts and Problems.
U.S. Bureau of Mines.  1985.  Minerals Yearbook 1985, Volume 1,  Metals  and
     Minerals.
U.S. Bureau of Mines.  1987.  Mineral Commodity Summaries.
                                   1-19

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Mining Engineering.  A journal of the Society of Mining Engineers, Inc.;
     several issues were used as reference.

E&MJ, Engineering and Mining Journal.  A monthly journal published by
     McGraw-Hill, Inc.; several issues were used as reference.
                                   1-20

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                         2.0  NONMETAL INDUSTRIES

INTRODUCTION

This section reviews the processes used to' recover 42 nonmetal commodities
from c"=s and concentrates.  Of 42 nonmetal commodities, 24 are not
recommended for further study for potential regulation under Subtitle C.
Several of the commodities not recommended for further study are produced
in manners that generate no vaste, that is all material mined is sold as
product with the exception of some water that is evaporated in drying
operations.  The rest of the commodities not recommended for further study
for potential regulation under Subtitle C are produced by methods that
generate wastes that do not have hazardous characteristics.

The 18 commodities for which further studies are recommended are not all
expected to require Subtitle C regulation.  Many are included in this list
because of (1) a lack of readily available information on waste
characteristics and (2) evidence that there is some potential for the
wastes to be hazardous.  Further study will be required to characterize
these wastes.
                                   2-1

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                                 DIATOMITE

Oiatomite, also known as diatomaceous earth and kieselguhr,  is a
sedimentary rock made primarily from the fossilized silica skeletons of the
diatom, a one-celled aquatic plant similar to algae whose two walls are
overlapping and symmetrical.  The tiny hollow skeletons of stable silica
give diatomite unusual properties leading to its use as a filter aid
(majority of consumption), filler and extender, thermal insulator, and in
many other applications.  Annual production is estimated to be 640 thousand
short tons (1986).

Diatomite occurs in massive deposits and is selectively mined to give a
crude product that contains few impurities.  The crude is crushed and dried
then sorted into site fractions.  Some fine material is heated to incipient
fusion in a kiln to produce a coarser material with specific properties.
All of the sizes of diatomite have some use, so there are no wastes
produced by processing.  Based on the above analysis, further study for
potential regulation under Subtitle C is not recommended.
                                    2-2

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                                  GARNET
Garnet is a silicate mineral used primarily as an abrasive,  although gem
quality garnets are produced.  The most familiar use of garnet is as the
abrasive coating on sandpaper.  It is also used to coat non-skid surfaces,
for sand blasting, lapping compounds, glass grinding, and as a filter
medium.  The U.S. produces 70X of the world supply of garnet and 1986
production was approximately 35,000 short tons.  No wastes with hazardous
characteristics are expected from garnet production.

Based on this analysis, further study of the garnet industry for possible
regulation under RCRA Subtitle C is not recommended.
                                 2-3

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                                 GEHSTONES

There are a vide variety of precious and semi-precious stones produced in
the U.S.  These include jade, opal, sapphire, tourmaline, turquoise, and
many others in small quantities.  The total value mined in 1986 vas
approximately $8.39 million, according to the U.S. Bureau of Mines "Mineral
Commodity Summaries 1987".  Some of the semi-precious stones are produced
as a by-product of other mining operations.  Particularly, turquoise is a
copper mineral and the majority of current production is from major open
pit copper mines.

The gem industry in the U.S. is extremely small and is unlikely to produce
any significant wastes with hazardous characteristics.  Therefore, further
study of this industry for possible regulation under RCRA Subtitle C is not
recommended.
                                   2-4

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                                GLAUCONITE

Glauconite, a hydrous iron, potassium silicate,  is a component of greensand
which gets its name because of glauconite's bluish-green to greenish-black
color.  Greensand also contains quartz and other silicates, and in some
cases pyrite.  Trace metals such as uranium, beryllium,  cobalt, chromium,
nickel, molybdenum, vanadium, and titanium also typically occur in
glauconite.  The industry is localized in the coastal plain of Nev Jersey
and Delaware.  Current annual production is approximately 4,000 tons, from
tvo producers.

Current use of glauconite are limited to 1) water treatment where it is
used to remove iron and manganese salts and 2) soil conditioning as a
mulch, top dressing or additive for gardening and potted plants (a
"natural" source of potash for organic farmers).

The hydraulicking method is used in mining glauconite at the Hungerford and
Terry's Inversand operation in Sewell, New Jersey.  Upper  layers of  the
deposit are removed to reveal ten to fifteen feet of relatively pure
glauconite.  The beds are flushed with a high-pressure water jet, and
loosened glauconite is suction-pumped through a complex piping system
containing special classifying and washing apparatus.  The wastes from this
washing contain clays and limonite, a rustlike iron mineral, and would not
be expected to exhibit any hazardous characteristics.  Lastly, glauconite
is treated with various chemicals, such as aluminum sulfate, sodium
silicate, sodium aluminate, caustic soda and phosphoric acid.  Little or no
waste is expected from this treatment.

Based on this analysis further study of this industry for  potential
regulation under Subtitle C is not recommended.
                                  2-5

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                                  GYPSUM
The mineral gypsum, calcium sulfate dihydrate (CaSO,.2H-0),  and the mineral
anhydrite, anhydrous calcium sulfate (CaSO.) are the  major  constituents of
evaporite deposits.  Although anhydrite represents the largest calcium
sulfate reserve, it has no commercial value.  The evaporite deposits may be
hear the surface or buried which will dictate whether open  pit or
underground mining is employed for mineral extraction.  Annual domestic
production of gypsum is estimated to be 16 million short tons (1986).
Major production areas are in California,  Iowa,  Michigan,  Oklahoma, and
Texas.  Fort Dodge, Iowa represents the largest  gypsum mining district in
the U.S. where 1979 production was approximately 1.2  million tons.  The
major use for gypsum is in the production of stucco which is in turn is
used to produce plaster and wallboard.  Stucco is produced  by rehydrating
calcined gypsum (otherwise known as plaster of paris, CaSO^.l/ZH-O) which
causes the material to set or harden.  Stucco is the hemihydrate C SO,.1/2
H-0 resulting from calcining gypsum.  Rehydrated it sets by returning  to
CaS04.2H20.

Gypsum requires little or no beneficiation in that the material mined  is
relatively pure and adequate for commercial use (85 to 95 percent pure).
To avoid beneficiation, care is taken during mining to selectively extract
specific grades of gypsum deposits, avoiding mixing in of overburden or
other rock or grades of gypsum.  Open pit mining utilizes draglines and
scrapers to remove overburden, and conventional techniques for mineral
extraction, i.e. blasting to loosen the gypsum,  and shovels or front end
loaders to load the material onto trucks.  Underground mining  is  typically
by room and pillar methods where 65 to 80 percent gypsum removal  is
achieved.  Compositions and volumes of wastes generated from  the  small
amount of beneficiation that does occur at some locations 'are  unknown;
however these wastes are not expected to exhibit any  hazardous
characteristics.
                                  2-6

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Based on this analysis further study of this industry for potential
regulation under Subtitle C is not recommended.
                                  2-7

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                       LIME, LIMESTONE, AND DOLOMITE

Limestones are sedimentary rocks containing mostly the mineral calcite
(calcium carbonate).  Dolomites are sedimentary rocks containing mostly the
mineral dolomite (calcium-magnesium carbonate).  Lime is a calcined (or
burned) form of limestone or dolomite that is made up of calcium oxide or
calcium and magnesium oxides.  Hydrated lime is calcium (or calcium and
magnesium) hydroxide produced by adding water to lime.  Among mineral
commodities, only sand and gravel are produced in larger quantity than
limestone and dolomite.  In 1981, approximately 644 million tons were
produced.

Limestones and dolomites are mined from deposits that meet the
specifications for a market.  The only processing may be washing to remove
clay, which would not be expected to show any hazardous characteristics
(Table 2-1), and screening to meet size specifications.  Clay washing is
necessary only in some operations.

The uses for which limestone or dolomite quality is the most critical are
the production of lime and portland cement.  In both cases, the feed
material is heated to high temperature (between 1,000° and 1150°C for lime
production) to produce chemical changes.  In lime production, the reaction
is called calcination and is the driving off of carbon dioxide from the
calcium carbonate, leaving calcium oxide, also called quicklime or hot
lime.  Calcined dolomite is a mixture of calcium and magnesium oxides.
There are several types of calciners used in the U.S. depending on
limestone type, fuel availability and other factors.  The coarse "lump"
products of calcination are usually sold without much further processing.
Some is crushed and sized to produce "pebble", "granular", "ground",  or
"pulverized" lime.  The fine material may be compressed into  pellets  or
briquettes or reacted with water to produce calcium hydroxide or "hydrated"
or "slaked" lime.  Some hydration is done under pressure  to ensure  the
maximum degree of hydration.  No wastes are produced by slaking.
                                    2-8

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Based on this analysis, further study of this industry for potential
regulation under Subtitle C is not recommended.
                                    2-9

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                                           TABLE 2-1

                           WASTES FROM LIME, LIMESTONE AND DOLOMITE
                                                           Possible RCRA Characteristic*
Process                 Vaste                              R   C   I   T       Comments


Vashing of Limestone    1) Clay Vaste                      N     N   N   N
 and Dolomite
* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined
  in 40CFR 261 Subpart C.

N - Vaste not expected to exhibit  this characteristic.
Y - Strong indication that waste would exhibit  this characteristic.
? - Possibility that waste could exhibit  this characteristic.

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                                  LITHIUM

Lithium is found in the mineral spodumene in pegmatites containing mineral
assemblages which are derived from the crystallization of postmagma tic
fluids or from metasomatic action by residual pegmatitic fluids.   Lithium
mineral concentrate, compounds and metal are produced by two companies (one
presently inactive) from lithium-fearing pegmatite ores in the
tin-spodumene belt of North Carolina.  Lithium carbonate is also produced
from subsurface brines in Clayton Valley, Nevada.  In 1980, the estimated
world consumption of lithium was 54.5 million pounds of lithium carbonate
equivalent.

Lithium ores and concentrates are consumed by the glass, ceramic, and
porcelain enamel industries.  Lithium hydroxide is used in the production
of lubricating grease.  Lithium carbonate is primarily used as.an additive
in aluminum refining and also in ceramics and glass.  Lithium carbonate (in
purified form) is used in the chemotherapeutic treatment of manic
depression.  Lithium chloride and bromide are used in absorption
refrigeration systems and dehumidification systems.
             \
The production of spodumene (a lithium aluminum silicate, LiAlSi-0,),
begins with the mined ore being crushed, ground, and classified as shown  in
Figure 2-1.  The next step is froth flotation with organic reagents.  The
froth flotation tailings (waste 1) consists of the pegmatite minerals and
would not be exposed to exhibit any hazardous characteristics.  Extraction
of lithium from spodumene is accomplished by the calcination of spodumene
to beta-spodumene.  Beta-spodumene is then reacted with sulfuric acid to
produce lithium sulfate.  Soda ash is added to convert  to  lithium
carbonate.

Lithium produced from brines is processed by pumping saline solutions into
large solar evaporation ponds (Figure 2-2).  During evaporation, halite and
sylvite crystallize.  Magnesium is precipitated as hydroxide  by  the
addition of lime during the evaporation  phase.  After  final concentration
                                  2-11

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                           Figure 2-1

                    LITHIUM ORE PROCESSING
Lithium Products 4-
                         Spodumene Ore
                               1
                             Size
                           Reduction
                             Froth
                           Flotation
                          Calcination
                               I
                          Dissolution
Precipitation
                     (1) Tailings (Quartz,
                         Mica, Feldspar)

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                            Figure 2-2

                       LITHIUM FROM BRINES
Lithium Carbonated-
                        Brine from Veils
                                1
                              Solar
                           Evaporation
                          Precipitation
                          with Soda Ash
Solid-Liquid
 Separation
                            2-13

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has been achieved, the brine is purified and lithium carbonate is
precipitated by the addition of soda ash.  No hazardous wastes are expected
from this process.

Table 2-2 summarizes the expected characteristics of the wastes from this
industry.  Based on this analysis further study of this industry for
potential regulation under Subtitle C is not recommended.
                                   2-14

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to
                                                                Table 2-2

                                                       LITHIUM  PRODUCTION WASTES
                                                           Possible RCRA Characteristic*
Process                 Waste                              R   C   I   T       Comments


Spodumine
 Concentration          1. Froth Flotation Tailings
                           (rock)                          N   N   N   N


* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined
  in 40CFR 261 Subpart C.

N - Vaste not expected to exhibit this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

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                                   MICA
The flake-like mineral mica occurs in differing chemical  'and  physical forms

of complex hydrous aluminosilicate.   The chemical composition of  micas is

described by a general formula which is X2Y4-6Z8°20 ^OH'F^4»  where x is
mainly K, Na, or Ca; Y is mainly Al, Mg, or Fe; Z is mainly Si or Al.

Approximately 60% of mica scrap (mica not in sheets) is from  North

Carolina.  The remaining mica comes  from Connecticut,  Georgia, New Mexico,

Pennsylvania, South Carolina and South Dakota.   Annual domestic production

is estimated at 153,000 tons (1986).


Flake and ground mica made from mica scrap are used in wallpaper, rubber

tires, paints, oil veil drilling fluids, Joint cement, surface coatings,

insulation boards, welding electrodes, and plastics.


In the mining of flake mica, conventional equipment removes any overburden

to expose the mica ore.  Once the mica ore is revealed, it is mined by

hydraulic methods, power-driven equipment, or a combination of both.


Recovery of mica can be accomplished utilizing three different methods.

Each method will be discussed below.
    1.  Washer Plant Methods (Figure 2-3):  High pressure water streams are
        first utilized to disintegrate mined ore.  It is then crushed and
        washed through trommel screens and again crushed with roll
        crushers.  The trommel screen removes the fine-sized, non-mica
        particles.  The remaining, coarser particles are crushed numerous
        times to remove all of the non-mica material.  After the crushing
        is completed, the final coarse mica is stored in bins.  None of the
        wastes are expected to exhibit any hazardous characteristics.

    2.  Humphrey's Spiral (Figure 2-4):  High pressure water washes the
        mined mica ore into a bowl rake classifier to be deslimed.
        Classifier sand is sent to 'a rod mill, then it is discharged to a
        trommel screen.  Larger material is returned and ground again in
        the rod mill.  The smaller material is passed to another bowl-rake
        classifier for desliming.  Humphrey's spirals are utilized for
        initial concentration of the classifier sand.  The rougher
        concentrate is fed into a cleaner spiral producing a cleaner
                                  2-16

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                   Figure 2-3

             MICA PROCESSING  BT VASQING
Coarse Mica
                      Hica  Ore
                    High Pressure
                    Water Stream
                    Disintegrator
                        Size
                      Reduction
                        Size
                     Separation
                        Size
                      Reduction
   Size
Separation
                   •(1)  Fine Waste
                        (Quartz,  Clay,
                        Feldspar,  Fine
                        Mica)
•>(!) Fine Waste as  above
    Note:  The size reduction and size separation
           steps are repeated until the maximum
           amount of undesirable material is removed.
                        2-17

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                     Figure 2-4

          MICA PROCESSING  BY  BUMPBEY SPIRALS
Mica Product
                       Hica  Ore
                          I
                     High  Pressure
                     Vater Stream
                     Disintegrator
                       Desliming
                         Size
                       Reduction
                       Desliming
                       Humphrey
                        Spiral
                     Concentrators
                      De lamination
Devatering
                       Vaste  Slimes
                   (2)  Vaste Slimes
                       Tailings (Quartz,
                       Clay,  etc.)
                       Fine Quartz
(5) Waste Water

-------
        concentrate, also known as middling.  This is middling is then
        passed back through the rougher spirals.  Screens are utilized to
        remove clay and fine-sized minerals from the cleaner concentrate.
        The oversized materials on the screen are then sent to a hammer
        mill in order to delaminate the mica and to remove quartz crystals.
        The final concentrate is once again screened, centrifuged, and
        stored.  The wastes from this process, mostly clays and quartz, are
        not expected to exhibit any hazardous characteristics.

    3.  Froth Flotation Methods:

        Acid Cationic (Figure 2-5); This froth flotation method recovers
        mica particles.  Sulfuric acid (to a pH of 4) conditions the ground
        mica ore pulp to allow for the greatest recovery.  The floating
        mica is recovered from the slurry by using a cationic reagent.

        Alkaline Anionic-Cationic (Figure 2-6);  In the presence of slimes,
        this method of froth flotation is effective in the recovery of
        mica.  Sodium carbonate and calcium lignin sulfonate are utilized
        to condition finely ground mica ore.  The mica is then floated and
        recovered with a combination of anionic and cationic collectors.
        Tailings from either flotation process would not be expected  to
        exhibit any hazardous characteristics.
This analysis has found that wastes from mica processing are unlikely  to
exhibit hazardous characteristics (Table 2-3) and therefore, further study

of this industry for potential regulation under Subtitle C  is not
recommended.
                                    2-19

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                       Figure 2-5

                   MICA PROCESSING BY

              ACID-CATIONIC FROTH FLOTATION
  Coarse Mica
Mica Products
                        Hica Ore
                           1
                          Size
                        Reduction
   Size
Separation
                        Desliming
   Froth
 Flotation
                  ->(!) Vaste Slimes
Tailings
                       2-20

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                      Figure 2-6

                   MICA PROCESSING BY

          ALKALINE ANIONIC - CATIONIC FLOTATION
  Coarse Mica
Hica Products
                        Hica Ore
                           1
                          Size
                        Reduction
   Size
Separation
                        Humphrey
                         Spiral
                      Concentrators
                        Desliming
   Froth
 Flotation
                  -*(!) Tailings
                  -»(2) Waste Slimes
Flotation Tailings
                         2-21

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I
o
J
                                                              Table 2-3

                                                       MICA  PROCESSING WASTES
                                                                             Possible RCRA Characteristic*
                  Process                  Waste                              R   C   I   T       Comments
Mica Washing

Humphrey's Spiral
Washing
Acid-Calionic
Froth Flotation
Alkaline Circuit
Flotation
Washer Tailings (Quartz,
Clay, etc.)
Waste Slimes (Clay)
Tailings (Clay, Silicates)
Slimes (Clays)
Flotation Tailing
Fine Tailings (Clays)
Flotation Tailings

N
N
N
N
N
N
N

N
N
N
N
N
N
N

N
N
N
N
N
N
N

N
N
N
N
N
N
N
                  * RCRA characteristics  are  Reactivity, Corrosivity, Ignitability and EP Toxicity as defined
                    in 40CFR  261  Subpart  C.

                  N - Waste not expected  to exhibit  this characteristic.
                  Y - Strong  indication  that  waste would exhibit  this characteristic.
                  ? - Possibility that waste  could exhibit  this characteristic.

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                                   PEAT
Peat consists of partially decomposed plant matter occurring in large beds
or bogs.  Coal beds are thought to be derived from ancient peat bogs that
have been heated and compressed over millions of years.  Peat is used in
the U.S. primarily in agriculture and horticulture and to a very small
extent as a fuel.  The Bureau of Mines estimated total production at
870,000 short tons in 1986 in the "Mineral Commodity Summaries 1987".  Peat
is used as mined and there are no significant wastes generated in peat
production.  For this reason further study of the peat industry for
possible regulation under RCRA Subtitle C is not recommended.
                                  2-23

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                                  PERLITE

Perilte refers to hydrated volcanic glass that can be expanded through
heating to form a lightweight aggregate for use in cryogenics, plaster,
concrete, and loose fill insulation.  The expanded form is also commonly
referred to as perlite.  Approximately 475,000 tons were mined in the U.S.
in 1986 with most of the mining occurring in New Mexico.  Perlite is also
mined in Arizona, California, Nevada, Idaho, and Colorado.

Perlite is mined through open pit mining of dome shaped deposits generally
hundreds of feet in height.  Friable textures of perlite can be extracted
by ripping with a dozer and loading the perlite into trucks for transport
to a processing plant.  Blasting may be required for harder ore, and other
techniques are employed to avoid clay seams, obsidian, and other
non-perlitic areas.

Figure 2-7 shows a typical general flow sheet for perlite processing.
Before expansion, perlite is crushed and screened to attain a specific size
range.   A jaw crusher is used to reduce the perlite to -3 in., .and then a
cone crusher and impact mill further reduce the perlite to -5/8 in. and
minus 8 mesh, respectively.  Various size grades of perlite are produced  by
vibratory screening and air classification.  These size grades are stored
and blended to meet demand specifications.  As seen in the figure, Waste  1
represents the fines from the screening and classification process.  These
fines are simply volcanic glass, and would not be expected to exhibit any
hazardous characteristics.

Perlite is subsequently heated and expanded to form the final product.
Heating is accomplished using either a horizontal or vertical furnace
operating at temperatures of UOOQF to 2100°F.  In the vertical  furnace,
the perlite falls through a chute into the hot zone where  the particles
expand creating a density change allowing  the particles to move with an
updraft into a cyclone.  Waste 2 in Figure 1 represents the  fines  from  the
                                 2-24

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                           Figure 2-7

                      PERLITE PROCESSING
Expanded Peril te<-
                          Perlite Ore
                               1
                             Size
                           Reduction
                         Particle Size
                           Separation
                           Expansion
                            Furnace
Particle Size
  Separation
                         Possible Waste
                         Fines
                   -> (2) Waste Rock
(3) Waste Fines
                            2-25

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cyclone, and vaste 3 represents the non-expansible particles like obsidian
and felsite which normally co-occur with perilte.  There vaste streams
would not be expected to exhibit any hazardous characteristics, as
summarized in Table 2-4.

Based on this analysis further study of this industry for potential
regulation under Subtitle C is not recommended.

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I
ro
                                                              Table 2-4

                                                     PERLITE PROCESSING WASTES
                                                           Possible RCRA Characteristic*
Process                 Vaste                              R   C   I   T       Comments


Screening and           1. Fines (Volcanic Glass)          N   N   N   N
 Classification

Expansion               2. Vaste Rock                      N   N   N   N

Cyclone                 3. Vaste Fines (Fine Perlite)      N   N   N   N
 Classification


* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined
  in 40CFR 261 Subpart C.

N - Vaste not expected to exhibit this characteristic.
T - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

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                                  POTASH
Potash is the generic term for a variety of potassium bearing minerals,
ores, and refined products.  Potassium is an essentiai. nutrient for plants.
Approximately 942 of U.S. potash consumption is used in fertilizers.   All
commercial potash production is from beds of salts formed by the
evaporation of salt lakes or seas.  Most potash is processed by one of
three processes, 1) froth flotation, 2) selective dissolution (washing)  of
undesirable minerals or 3) precipitation of potash minerals from natural or
artificial brines.  Domestic production in 1983 was 1,429,000 metric tons.

Sylvinite ore (potassium chloride-sodium chloride) is commonly beneficiated
by the process of froth flotation.  As shown in Figure 2-8, the ore is
first ground into a slurry with the brine.  Grinding releases sylvite and
halite particles from their agglomeration.  The slurry is then deslimed to
remove the fine contaminants (mostly clays and hematite) (Waste 1).  The
slurry then goes to the froth flotation circuit where the sylvinite is
floated from the halite in an aqueous solution saturated with both sodium
and potassium chlorides.  Halite (rocksalt) is the waste product (Waste 2
in Figure 2-8).

Langbeinite is a mixed potassium sulfate-magnesium sulfate mineral that is
relatively insoluble in water.  Langbeinite ores are often upgraded by  the
process of dissolution of the soluble halite and other salts  that occur
with it.  This selective dissolution (Figure 2-9) would have a brine as a
waste product.

Some ores are processed by the third process of dissolving  the sylvenite
and precipitating a pure sylvite product  from  the clarified brine  (Figure
2-10).  Natural brines, such as those  found at Great  Salt  Lake, UT or
Searles Lake, CA, are also treated  to  precipitate potassium compounds.  At
one operation in Utah, an unsuccessful underground mine was flooded and
potassium compounds are produced by solar evaporation of  the  resultant

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                    Figure 2-8

          POTASH FROTH FLOTATION PROCESSING
  Sylvite
Concentrate
                    Sylvenite Ore
                          I
                        Size
                      Reduction
                      Oesliming
  Froth
Flotation
                 -»(1) Waste Slimes
•+(2) Flotation Tailings
      (Halite)

-------
        Figure 2-9

POTASH SELECTIVE DISSOLUTION
       Langbenite Ore

              i
         Dissolution
Langbeinite Product
        Solid-Liquid
         Separation
-»(1) Waste Brine (Salt)

-------
    Figure 2-10

POTASH PRECIPITATION
Sylvite Product
 Natural or Solution
    Mining Brine
     Evaporation
    Solid-Liquid
     Separation
(1) Waste Brine (Salt)

-------
brine.  The wastes from these processes would contain considerable amounts
of readily soluble salts but they may not contain any hazardous components
(Table 2-5).

Based on the above analysis, further study of this industry for potential
regulation under Subtitle C is not recommended.

-------
                                           Table 2-5

                                   POTASH  PROCESSING WASTES
Process
Waste
Possible RCRA  Characteristic*
R   C   I   T        Comments
Froth Flotation


Selective Dissolution

Potash Precipitation
1. Vaste Slimes (Clays)            N   N   N   N
2. Flotation Tailings (Halite)     N   N   N   N

1. Waste Brine (Halite)            N   N   N   N

1. Waste Brine (Halite)            N   N   N   N
* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined
  in 40CFR 261 Subpart C.

N - Vaste not expected to exhibit  this characteristic.
Y - Strong indication that waste would exhibit  this characteristic.
? - Possibility that waste could exhibit  this characteristic.

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                                  PUMICE
Pumice is the lightweight rock produced from volcanic eruptions.  It is
produced by the expansion of gases in silicic lava.  Pumice deposits are
formed in the volcanic regions of the United States, ranging :rom the State
of Washington to California and the Havaiian Islands.

Pumice has a lov density and has very good abrasive properties.  The main
use of the material is in construction applications, such as road surfacing
material and railroad ballast.  It also has some industrial applications as
an abrasive.  Production of pumice in 1986 was estimated to be 415,000
short tons.

Pumice is mined in an open pit.  The pumice is transported from the pit to
a crushing and screening plant.  This is usually the only processing
necessary for construction grade material.  To be used as abrasives in
industry, finer grinding is usually necessary (Figure 2-11).  There are no
known wastes resulting from this processing.

Based on the above analysis, further study of this industry for potential
regulation under Subtitle C is not recommended.
                                    2-34

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                      Figure 2-11

                   PUMICE PRODUCTION
Construct ion
Grade Pumice
Industrial
Grade Pumices-
                        Pumice
                       Crushing
  Screening
Fine Grinding

-------
                               PYROPHYLLITE

The mineral pyrophyllite is a hydrous aluminum silicate.  Pyrophyllite was
produced domestically in 1983 from 5 sites in North Carolina and tvo in
California.  Domestic production in 1983 was 87,000 short tons.

Pyrophyllite is a talc like mineral used primarily in refractory materials,
ceramic materials, and insecticides.  To a lesser extent pyrophyllite is
used in various filler applications much like talc.

Selective mining produces pyrophyllite ores that only need to be ground to
meet the size specifications of the market for vhich it is being prepared.
This size reduction produces no waste.

Based on the above analysis, further study of this industry for potential
regulation under Subtitle C is not recommended.

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                        SALT AND ROCK SALT (HALITE)

Salt (common name for sodium chloride) is found in nature in sea water,
natural brines and as rock salt (halite).  Salt is an essential nutrient
and flavoring agent for man.  Salt is used widely in the chemical industry
(over 50% of annual consumption) and rock salt is used as a deicer for
roadways and sidewalks.  Salt is produced by dry mining, solution mining
and by solar evaporation.  In 1986, 39 companies operated 68 plants in 14
states to produce an estimated 37 million short tones of salt (USBM,  1987).

Rock salt is mined underground from thick beds of salt at several locations
in the U.S.  Most rock salt is simply mined, crushed and screened and sold
by size.  Some is upgraded by the removal of particles of anhydrite
(calcium sulfate), shale and dolomite (calcium-magnesium carbonate).   These
waste rocks would not be expected to show any hazardous characteristics
(Table 2-6).  Very pure salt is produced by dissolving fine crystal rock
salt in hot brine.  The high temperature dissolution leaves behind the
calcium sulfate and when the salt is recrystallized it may be as pure as
99.99% sodium chloride.  The calcium sulfate is not expected to be
hazardous (Lefond and Jacoby, 1983).

Another process for extraction of salt from thick beds is solution mining
wherein a well is drilled into the bed and the area surrounding the bed  is
hydraulically fractured.  Water is then pumped in and brine pumped out.
Approximately 50% of all salt is produced by this method.  Much of the
brine is used directly in the chemical industry; and a smaller amount is
crystallized in evaporators.  Some brine purification is done on chemical
plant and evaporator feeds, leaving a residue.  This residue is not
expected to exhibit hazardous characteristics and  is reinjccted  into  the
formation.

The solar evaporation of naturally occurring salt solutions has been
practiced for many years.  The main sources of salt solutions are  the
                                  2-37

-------
ro
*>
'£>
                                                                              Table  2-6

                                                                      WASTES FROM SALT PRODUCTION
Process
Rock Salt Recrystallization
Brine Purification
Waste
1) Calcium Sulfate
2) Brine Purification Residue
R
N
N
C
N
N
I
N
N
T
N
N
Characteristic
Gjnnents
Recycled to solution
                                                         (Mg, Ca, Fe, S04, etc.)
                     Solar Evaporation
3) Bittern (NaCl, MgCL,      ,,
   KC1,
                     Kining

N      N      N      Hay  be processed to
                     recover Magnesium and
                     Potassium.
                     * RCRA characteristics are Reactivity, Gorrosivity, Ignilability and EP Toxicity as defined  in 40CTR 261 Suboart C.

                     N - Uaste not expected to exhibit this characteristic.
                     Y - Strong indication that waste would exhibit this characteristic.
                     ? - Possibility that waste could exhibit this characteristic.

-------
oceans and salt lakes such as the Great Salt Lake, Utah.  In this process,
the salty brine is pumped into shallow ponds where the water evaporates
concentrating the brine.  Compounds of calcium, magnesium and iron
precipitate at this stage.  The brine is transferred to a lime pond to
remove calcium sulfate.  From the lime pond, brine is transferred to
harvesting ponds where approximately 85£ of the salt crystallizes and
settles out.  The remaining solution, called "bitterns" is drained to
adjacent ponds for further processing or disposal.  Bitterns is a
concentrated solution high in magnesium compounds, but still contains
sodium chloride.   Brine is put into the harvesting ponds for
crystallization several times between salt harvesting to build up a
sufficient layer of salt for the mechanical harvesters to remove.  Prior  to
mechanical harvesting, the salt is washed with dilute brine to remove
residual bitterns and impurities.  After harvesting, the salt is
transferred to processing facilities where it is washed with fresh water,
dried, screened and shipped.

Based on the above analysis, further study of this industry for regulation
under Subtitle C is not recommended.
                               2-39

-------
                                REFERENCES


Lefond and Jacoby, Salt, Industrial Minerals and Rocks, Stanley J. Lefond,
    ed.  Society of Mining Engineers of AIME, 1983.

USBM, Mineral Commodity Summaries 1987.

USBM, Mineral Facts and Problems 1985.

USBM, Minerals Yearbook 1985.
                                 2-40

-------
                      SAND AND GRAVEL AND CRUSHED STONE

 Three mineral commodities that are very closely related  in  makeup  and
 processing are construction sand and gravel,  industrial  sand  and gravel,
 and crushed stone.  Crushed stone is the largest of these industries in
 terms of output with 1986 production estimated at 1 billion tons,  valued  at
 $4.2 billion.  There were 1,790 companies operating 3,560 quarries in  49
 states.  The construction sand and gravel industry consists of 4,300
 companies with 5,900 operations, in 50 states, that produced  837 million
 short tons valued at $2.6 billion.  The industrial sand  segment produced  29
 million short tons from 169 operations owned  by 98 companies  in 38 states.
 Crushed stone and construction sand and gravel are used  for construction
 aggregate, fill, metallurgical flux, and many other uses, some of  which
 (such as cement or lime manufacturing) are discussed in  other screening
 studies.  Industrial sand and gravel is used  for glass making (discussed
 under Silica Sand), foundry sand, abrasive sand, hydraulic fracturing sand,
 and many other applications.

 Processing of crushed stone is done by simple crushing and screening to
 provide the size grades desired in the final  product.  The only waste
 expected would be fugitive dust which would not be expected to exhibit any
 hazardous characteristics.

 Construction sand and gravel is mined from river beds, glacial moraines,
 river terraces, alluvial fans, and other such deposits.   The primary
 processes are drying, screening, and blending to meet size specifications.
 Some coarse materials may be crushed or ground if  the deposit does  not
 contain enough fine material to meet specifications.  Undesirable materials
 do occur in some deposits and they must be removed  to make the sand and
'gravel saleable.  Clays are removed by washing in  water  producing a slurry
 containing the fine material which is sent to waste.  This waste  is not
 expected to exhibit any hazardous characteristics.  Undesirable dense
 material is removed by jigging or heavy medium separation.  The heavy
                                    2-41

-------
medium used in this separation is usually a slurry of finely ground
magenetite or ferrosilicon in water.  The heavy minerals removed by Jigging
heavy medium separation are discarded.  This vaste is not expected to
exhibit any hazardous characteristics.

Industrial sand and gravel is processed by the same methods as construction
sand and gravel, except for glass sand and other specialty materials
discussed separately.  The wastes from industrial sand processing are not
expected to exhibit any hazardous characteristics.

The industries of crushed stone, construction sand and gravel, and
industrial sand and gravel share similarities in product and waste
characteristics.  None of the waste from these industries are expected to
exhibit hazardous characteristics.  Therefore, further study for potential
regulation under Subtitle C is not recommended.
                                   2-42

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                                 SODA ASH
Soda ash (Na-CO^) production in the United States is from the benef iciation
and processing of the evaporite mineral, trona (Na^O^.NaHCO^.Zf^O) •   The
most extensive deposits of trona are in the Green River Formation of
southwest Wyoming, where trona (typically 70 percent Na2CO.) occurs in flat
beds of two to six meters thickness at depths from 100 to 1070 meters.  The
trona resource of 11 such beds is estimated at 52 billion tons.  Production
of soda ash from Green River, Wyoming, in 1986, was approximately 7 million
tons.  The other major deposit of soda ash is at Searles Lake, California,
where sodium carbonate is a component of brines (5 percent N32CO.,) within a
series of permeable crystalline saline lenses (primarily halite).
Production of soda ash from natural resources has totally replaced
principle production of soda ash by the Solvay process in the United
States.  In the Solvay process, sodium chloride brines are ammonia ted,
carbonated, and calcined.  The higher production cost of the Solvay
process, together with the cost for environmental controls was largely
responsible for its demise.  The soda ash market is dominated by the glass
industry (50 percent) and the inorganic chemical industry (30 percent),
principally phosphates and silicates.

Extraction of trona is by underground room and pillar mining (Green River,
Wyoming) or by brine withdrawal via production wells (Searles Lake,
California) .

Processing of the Green River trona is one of crushing, calcining  (to
remove CO- and organics), dissolution, removal of extraneous solids by
sedimentation and filtration, removal of soluble organics by adsorption  on
activated carbon, crystallization of  the monohydrate by evaporation
(multiple effect evaporation), filtration to concentrate the crystals, and
lastly drying and cooling to produce soda ash  (Figure 2-12).  The  major
waste streams are the muds produced from sedimentation and  filtration
(waste streams 1 and 2) and waste brine from the vacuum filter (waste
                                   2-43

-------
                          Figure 2-12

                       TRONA PROCESSING

                       VTOMING PRACTICE
Soda Ash Products
                           Trona Ore
                               1
                              Size
                            Reduction
                              I
                           Calcination
                           Dissolution
                          Solid/Liquid
                           Seporation
                           Filtration
                            Polishing
                         Crystallization
                          Solid/Liquid
                           Separation
Dryer
                 (1)   Insoluble  Hud
                 (2)  Insoluble Mud

-------
stream 3)(Table 2-7).  The insolubles (shale and shortite) are sent in
slurry form to tailings ponds which have a pH of approximately 10.

The Searles Lake brine process is similar to the Vyoming process  in that
the sodium carbonate precipitate is calcined, dissolved, reprec-ipi tated as
the monohydrate, filtered, and dried to remove free water.  The brine is
initially carbonated using CO- from a lime kiln or power plant, the crude
monohydrate slurry is separated by sedimentation and subsequently  washed
and filtered.   The solids are then dried, calcined, and bleached,  producing
a light ash.  The light ash is converted to a dense ash by dissolution,
reprecipitation as the monohydrate, and filtration and drying  to  remove
free water.  The five waste streams represent clarifier overflows  or
filtrate and have a pH of approximately 10 (Table 2-7).  The current
industry practice is to reinject these brines back into the formation,
dissolving more sodium carbonate.

Based on the above analysis, further study of this industry for potential
regulation under Subtitle C is not recommended.

-------
                                             Table 2-7

                                        SODA ASH WASTES
Process
Searles Lake Brines







Wyoming Trona



Waste
1.
2.
3.

4.

5.

1.
2.
3.

Clarifer Overflow
Washing Filtrate
Seed Crystal Washing
Filtrate
Honohydrate Clarifier
Overflow
Honohydrate Washing
Filtrate
Waste mud (clays)
Waste mud (clays)
Honohydrate Washing
Filtrate
Possible
R C ]
N
N

N

N

N
N
N

N
N
N

N

N

N
N
N

N
RCRA Characteristic*
[ T Comments
N
N

N

N

N
N
N

N
N
N

N

N

N
N
N

N
All wastes will
show a high pH but
they are not
expected to be
corrosive
(pH>12.5)






* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity  as  defined
  in 40CFR 261 Subpart C.

N - Waste not expected to exhibit this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

-------
stream 3)(Table 2-7).  The insolubles (shale and shortite) are sent in
slurry form  to tailings ponds which have a pH of approximately 10.

The Searles  Lake brine process is similar to the Wyoming process in that
the sodium carbonate precipitate is calcined, dissolved, reprecipitated as
the monohydrate, filtered, and dried to remove free water.  The brine is
initially carbonated using CO. from a lime kiln or power plant, the crude
monohydrate  slurry is separated by sedimentation and subsequently washed
and filtered.  The solids are then dried, calcined, and bleached, producing
a light ash.  The light ash is converted to a dense ash by dissolution,
reprecipitation as the monohydrate, and filtration and drying  to remove*
free vater.  The five waste streams represent clarifier overflows or
filtrate and have a pH of approximately 10 (Table 2-7).  The current
industry practice is to reinject these brines back into the formation,
dissolving more sodium carbonate.

Based on the above analysis, further study of this industry for potential
regulation under Subtitle C is not recommended.

-------
                                              Table 2-7

                                        SODA ASH WASTES
Process
Waste
Possible RCRA Characteristic*
R   C   I   T       Comments
Searles Lake Brines







Wyoming Trona



1.
2.
3.

4.

5.

1.
2.
3.

Clarifer Overflow
Washing Filtrate
Seed Crystal Washing
Filtrate
Monohydrate Clarifier
Overflow
Monohydrate Washing
Filtrate
Waste mud (clays)
Waste mud (clays)
Monohydrate Washing
Filtrate
N
N

N

N

N
N
N

N
N
N

.N

N

N
N
N

N
N
N

N

N

N
N
N

N
N
N

N

N

N
N
N

N
All wastes vill
show a high pH but
they are not
expected to be
corrosive
(pH>12.5)






* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined
  in 40CFR 261 Subpart C.

N - Waste not expected to exhibit this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

-------
                              SODIUM SULFATE

Many dried lake beds and natural brines in Arizona,  California,  Nevada,
North Dakota, Texas and Utah contain large quantities of natural sodium
sulfate in the form of thenardite and mirabilite.   Naturally derived sodium
sulfate produced by three companies operating four plants in three states
in 1983 produced 435,000 short tons.  Sodium sulfate, produced as a
byproduct from other industries in 1983, amounted  to 665,000 short tons.

Mirabilite (Na2SO,.10H-0), otherwise known as a Glauber's salt,  is the most
abundant of the sodium sulfate minerals and represents the sodium sulfate
deposits of commercial significance.  Mirabilite is a large component of
evaporites and occurs as crystalline beds within brines or beneath playa
lakes.  The major use of sodium sulfate is in the  detergent industry.
Sodium sulfate acts as a filler and diluent.  Sodium sulfate is also used
in the glass industry where sulfate is used to modify the physical
characteristics of the glass and in the production of kraft paper pulp
where sulfate is reduced to sulfite, an active component of pulping liquor.

There are three major types of processing of brines in the production of
anhydrous sodium sulfate; the Ozark-Mahoning process used in Vest Texas,
Kerr-McGee's process at Searles Lake (Figure 2-13), and the process used by
the Great Salt Lake Minerals and Chemicals Corp. in Utah.  The
Ozark-Mahoning process is shown in Figure 2-14.  In this process, brines
are refrigerated to selectively precipitate Glauber's salt which  is
subsequently filtered and washed.  Washing produces a saturated solution of
Glauber's salt which is converted to the anhydrous form in mechanical vapor
recompression crystallizers.  The anhydrous salt is separated from  solution
by centrifugation, and the centrate returned to the combustor.  Anhydrous
sodium sulfate is lastly dried in a rotary kiln.  The only waste  that can
be identified at this time are those resulting  from filtration  and  washing
of the Glauber's salt (Table 2-8).  These wastewaters are reinjected  into
the salt formation in seme manner.
                                  2-47

-------
                      Figure 2-13

              SODIUM CARBONATE PROCESSING

               SEARLES LAKE, CA PROCESS
Light Soda Ash
Dense  Soda Ash
                          Brine
                            ;
                       Carbonation
                          Tower
                         Clarifier
                          Washing
                         Filtration
                           Dryer
                         Calciner
Bleaching
 Furnace
                        Dissolution
                      Reprecipitation
                            I
                         Clarifier
                          Filtration
  Dryer
                   (1)  Clarifier  Overflow
                   (2)  Filtrate
                    (3) Clarifier  Overflow
                    (4)  Filtrate

-------
The Searles Lake process is similar to the above described process,
however, in this case other salt products are produced.  For instance,
sodium carbonate is recovered through precipitation caused by carbonation
of the brine.  The sodium bicarbonate free brine is refrigerated to
selectively crystallize borax and then further cooled to precipitate
Glauber's salt.  Major impurities are sodium chloride and soda ash.

The process used at the Great Salt Lake relies on solar evaporation and
winter cooling of brines for selective precipitation of sodium sulfate.
The harvested Glauber's salt is melted and anydrous sodium sulfate
precipitated by the addition of sodium chloride to reduce its solubility
through the common ion effect.

Based on the foregoing discussion, further study of this industry  for
potential regulation under Subtitle C is not recommended.
                                   2-51

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                                STAUROLITE

Staurolite is an iron-aluminum silicate mineral that is commonly used as a
sandblasting agent.  It is also used as a foundry sand and as s source of
aluminum in portland cement manufacture, where aluminum is not otherwise
available.  The only known production of Staurolite in the United States
occurs in Florida, where E.I. duPont de Nemours coproduces Staurolite in
association with its titanium mining operation.

Staurolite and other silicates are separated from titanium ore by high-
tension separation.  The Staurolite is then magnetically separated from  the
other silicates.  The resulting Staurolite concentrate contains mainly
Al-O- with lesser amounts of F620-, ZrO-, TiO-, and free silica.  The
concentrate is graded into fine, medium, and coarse fractions and packages
(Figure 2-15).

The only known byproduct from production operations is the silica waste
coming from the magnetic separator.  The common silicates found in the
titanium deposit are zircon (ZrSiO,), kyanite (AljSiOc), sillimanite  •
(Al2Si05), and tourmaline (Na, Ca) (Li, Mg, Al) - (Al, Fe, Mn)fi (B03>3 -
(Si,0.g) (OH)^.  None of these minerals contain EP Toxic metals.

Based on the above analysis, further study of this industry for potential
regulation under Subtitle C is not recommended.
                                 2-52

-------
                             Figure 2-15

                        STAUROLITE PRODUCTION
       Titanium Ore
Staurolite Products*-
                            Titanium Ore
                                  I
High Tension
Elecrostatic
 Separation
                              Magnetic
                             Separation
  Gra'ding
                   •> Non-Magnetic
                     Silicate Waste

-------
                              BUILDING STONE

For the purposes of this study, building stone will be defined as all stone
used as a building material for decorative purposes or as a sole structural
material.  This includes, but is not limited to, ashlar stone, cut
(dimension) stone and rubble and rough construction stone.  These are
primarily used as facing stone for appearance, and consist of a vide
variety of natural types.  Stone used for structural purposes is somewhat
more limited in type.  All such stone is mined in a very selective manner
vith negligible waste from mining and little if any from finishing.  What
wastes are produced would not be expected to exhibit any hazardous
characteristics.

Based on the above analysis, further study of this industry for potential
regulation under Subtitle C is not recommended.

-------
                                  SULFUR
Sulfur is a non-metallic element videly used in industry both as elemental
sulfur (brimstone) and in sulfuric acid.  Sulfur has three basic sources.
Native or elemental sulfur, combined sulfur, and recovered sulfur.   Native
sulfur is found in salt domes, stratigraphic deposits and volcanic
deposits.  Combined sulfur occurs in natural compounds such as iron pyrite,
copper sulfides and gypsum.  Recovered sulfur is produced as a by-product
of other processes, such as oil refining or base metal smelting.

In the U.S., the Frasch process for mining elemental sulfur produced about
372 of the total U.S. production of 11 million tons of sulfur in 1986,
sulfur from pyrite accounted for 2% and recovered sulfur accounted  for the
remaining 61%.

The Frasch process uses hot vater to melt sulfur trapped in salt domes.
The sulfur is then pumped to the surface and-is either sold as a liquid or
cooled and solidified into a number of forms for market.  The vater
migrates to the edges of the sulfur deposit where it is removed by "bleed
water" wells and discharged.  This bleed water is not expected to exhibit
hazardous characteristics.  There has been sporadic production of elemental
sulfur from volcanic deposits in the western U.S., but it has been very
small and the selective mining used would eliminate wastes.

Sulfur from pyrite (iron sulfide) is produced by roasting (burning)  the
pyrite to produce sulfur dioxide gas and iron oxide solid.  The gas  is
treated to produce either liquid sulfur dioxide or sulfuric acid and  the
iron oxide may be sold as feed for iron making.  If the iron oxide is not
sold, it is not expected to exhibit any hazardous characteristics as  a
waste.

-------
Recovered sulfur production is not vithin the scope of this study, except
as a part of the study of vastes from primary metal production, and vill
not be addressed here.

Based on the above analysis, further study of this industry for possible
regulation under Subtitle C is not recommended.

-------
                                   TALC
The mineral talc is a soft, hydrous magnesium silicate.   There are three
talc containing minerals (talc, soapstone and steatite).   Talc was produced
domestically in 1983 from 26 mines in 12 states.   Production in 1983 vas
980,000 short tons vith 97% produced in Texas, Vermont,  Montana, Nev York
and California.

Massive solid talc that is relatively pure is sold as steatite and is
suitable for making electronic tube insulators.  Less pure solid talc is
called soapstone.  Soft massive talc is some times called "French Chalk",
and is used to make talc crayons.   Platy and soft talc is used in a very
vide variety of industries, including paint as a filler,  paper for
coatings, ceramics, cosmetics, plastics as a filler, roofing materials and
in the rubber industry, again as a filler.
       i

This vide variety of uses leads to a variety of specifications.  Selective
mining and hand sorting are the methods most commonly used to improve the
quality of the crude talc group minerals.  Massive steatite is used as
mined, and is just curved to shape.  Much soft talc is processed dry,
simply being ground to the proper size (generally very fine) in a series of
steps. High grade products require more elaborate processing by froth
flotation.  Figure 2-16 shovs a general flotation flovsheet including
crushing, drying, flotation, thickening and final drying.  The waste
products from flotation are sent to a tailings pond.  The vaste products
vould typically be carbonates such as limestone or dolomite vith some fine
talc and other accessory minerals.  These wastes vould not be expected  to
be hazardous.

Based on the above analysis, further study of  this industry for potential
regulation under Subtitle C is not recommended.
                                  2-57

-------
   Figure 2-16
TALC  PROCESSING
TAiC ORE


     JAW CRUSHER
       SCREEN
  Undeni/e      Overut
               \
CTRATORT CRUSHER
I
ROTARY OUTER
.
| PEBBIE Will ROLLER Mill ]
t I
AIR CLASSIFIER AIR CLASSIFIER I
I I I
Co*ru fines Ptoducu
1 1
[ OOUBU DECK SCREEN ]
1 1
Qvcrufi Undtrsut Oversut (topi
III
Pioducts Wiiw
I CONCENTRATING TABIES 1
1 1
1 1
HASH DRYER 1 FROTH FLOTATION 1 N«ttlC<*
1 \ \
PUIVER12ER 1
(VfRTirill ____. * __i^


Products
FIIURS
1
*ft Conctnnut
M«gnttil*

-------
                                  TRIPOLI

Tripoli is a finely divided, microcrystalline form of silica that is a
recrystallization of siliceous limestone or calcareous chert leachate.
Pulverized tripoli is used in abrasives, buffing and polishing compounds,
and inert mineral fillers.  Silica treated by surface adsorption of
organ!cs with organofunctional groups is used in thermoplastic and
thermosetting resins for molded engineering plastics, casting compounds,
adhesives and coacings.  Tripoli is found throughout the southeast United
States.  The distribution is broken down into districts.  These districts
are the Missouri-Oklahoma, Southern Illinois, Arkansas, Vest Tennessee
River Valley, and other areas in the southeastern United States.  The
distribution is broken down into districts.  These districts are the
Missouri-Oklahoma, Southern Illinois, Arkansas, West Tennessee River
Valley, and other areas in the southeastern United States.  Approximately
100,000 short tons of tripoli was produced in 1980.

Open cut or underground room and pillar methods are used to mine tripoli.
The processing is very simple, the ore is crushed, dried, and ground  to
produce the final product.  None of these stages of processing produces
waste (with the exception of moisture loss, all of the mined material ends
up as product).  Therefore, further study of this industry  for potential
regulation under subtitle C is not recommended.

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                                VERMICULITE

Vermiculite is the name given to a family of mica-like hydrated
ferromagnesian silicate minerals.  These minerals expand,  when heated,  to
approximately 30 times their original size.  The resulting product is a
lightweight insulator that is used in construction and as  a lightweight
carrier material for fertilizers and pesticides and herbicides.  Production
of vermiculite in the United States has remained fairly constant over the
last decade, at just over 300,000 short tons per year.

Vermiculite deposits in the United States occur mainly in  the Piedmont
region from Alabama to Pennsylvania and in the Rocky Mountain Range from
Montana into New Mexico and Texas.  Mining of vermiculite  is known to occur
in Libby, Montana, Enoree, South Carolina and Louisa County, Virginia.

Processing of vermiculite generally involves separation, sizing, and
heating operations (Table 2-9).  These operations do not always occur at
the milling site.  Rough screening may be done at the mining site, and the
heating operation may be centrally located to a number of  mining sites.
The specific processing operations of the tvo largest mines are discussed
below.

The flowsheet for the Libby, Montana, plant is shown in Figure 1.  The
preliminary screening plant is between the mine and the mill.  The
preliminary screening plant removes the waste rock from the raw vermiculite
ore.  The waste rock (waste 1 in Figure 2-17) is disposed  of in piles near
the mining area and is not expected to exhibit any hazardous
characteristics.  The raw ore is sent to the mill for rough size
fractionation producing Vaste 2; then water is added  to the ore and  further
concentration takes place by gravity separation.  This process generates
tailings (waste 3) vhich are sent to, a tailings pond.  The  clean water is
pumped from the top of the tailings pond to a clean water reservoir  and  is
then reused in the plant.  The wet concentrate goes to a drying operation
and is sized before being shipped to the exfoliation  (heat  treating)  plant
                                    2-60

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                                             Table 2-9

                                    VERMICULITE PROCESSING
                                                           Possible RCRA Characteristic*
Process                 Waste                              R   C   I   T       Comments
Primary Screening
Rough Sizing
Separation
1.
2.
3.
Waste Rock
Waste Rock
Tailings (Waste Rock Fines)
N
N
N
N
N
N
N
N
N
N
N
N
                        4. Baghouse Dust

Exfoliation             5. Baghouse Dust                   N   N   N   N


* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity  as  defined
  in 40CFR 261 Subpart C.

N - Waste not expected to exhibit  this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit  this characteristic.

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                             Figure 2-17

                       VERHICULITE PROCESSING
Vermiculite Products-
                                   Ore
                                1
                            Primary Size
                             Separation
                             Rough Size
                             Separation
                            Concentration
                               Drying
                                Final
                              Screening
                                 1
Exfoliation
   Heat
 Expansion
                 -* (1)  Waste Rock
                    (2)  Waste Rock
                        Tailings
                                                 •(4) Baghouse Dust
(5) Baghouse Dust

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off-site.  The building exhaust system goes to a bag filter which generates
a solid waste stream waste A.  The final disposition of this waste is not
known, but it is not expected to exhibit any hazardous characteristics.

In the South Carolina operation, the ore is sent to the mill as a wet
slurry.  The slurry goes through desliming and beneficiation steps, then is
dewatered.  The dewatered concentrate is dried and screened before being
sent to an exfoliation plant off-site.  These processes generate a number
of aqueous waste streams that are sent to tailings ponds.  The clarified
water from the ponds is reused in the plant.

Exfoliation involves heating the vermiculite concentrate at high
temperatures (2000 -  3600°F) for a short time.  After the material leaves
the furnace, the rock impurities are removed from the vermiculite.  The
product is then packaged and shipped.  Most furnaces have bag collectors
for dust control which produces waste 5 in Figure 2.  The waste management
methods for the rock impurities and bag collector dust are not known,  but
they probably will not show any hazardous characteristics.

For these facilities, there is little information available on the
quantities or characteristics of the waste streams.  Table 1 summarizes
what is known.  However, the quantities are probably small and it  is
expected that they would not exhibit any hazardous characteristics.
Therefore further study of the vermiculite industry for potential
regulation under Subtitle C is not recommended.
                                   2-63

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                               VOLLASTONITE

Pure wollastonite is a calcium metasilicate with the composition 48.3
percent CaO and 51.7 percent S10-.  The United States is the largest
producer of wollastonite in the world, with New York and California the two
producing states.  Production in New York is from an extensive deposit
located on the western side of Lake Champlain near Villsboro.  In
California, wollastonite is produced by Pfizer Incorporated.  Vollastonite
is also found in the states of Arizona, Nevada, Idaho, Utah, and New
Mexico.  Production in the United States (California and New York) is
considered company proprietary data.

Vollastonite is utilized by the plastics and coatings industries as a
filler and extender, and as a partial substitute for fiberglass and for
asbestos.  Other consumption is for thermal insulation, ceramics,
refractories, metal casting plasters, fluxes, matchheads,  abrasives,
pesticide carriers, and friction papers.

Vollastonite is mined by open pit/open stope methods.  At Villsboro, New
York, extracted ore is crushed, screened, and concentrated using magnetic
separators.  The high intensity magnets separate both garnet and diopside
which are presumably byproducts that are not wasted and would not be
expected to exhibit hazardous characteristics even as waste.  The
beneficiated wollastonite is further ground in pebble mills or attrition
mills to produce grades of granular and fibrous wollastonite, respectively.

The mining and processing of wollastonite does not appear to produce any
significant quantities of waste, and any such waste  is unlikely  to have
hazardous characteristics.  Therefore, further study of this industry  for
potential regulation under Subtitle C is not recommended.

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                                  BARITE
Barite is the naturally occurring mineral form of Barium Sulfate
and is produced both from gravel type deposits (residual) and from beds or
veins.  Most residual production is from Georgia, Missouri and Tennessee
while veins and beds are mined in Nevada.  Barite is used as a component of
petroleum drilling muds (due to its density of 4.5 gm/cc), glass making,
paint and to make barium chemicals.  Annual domestic production is
estimated at 378,000 short tons (1986).

Residual ores are mostly clay with rounded barite and siliceous gravels.
Treatment consists of breaking down the residuum, washing out the clay and
removing the siliceous gangue by density separation (see Figure 2-18).  As
shown in the figure, four waste streams are produced in  this treatment.
Waste stream 1 consists of the cobbles and other large rocks, and waste
stream 2 consists of clays and other very fine materials including barite.
In Missouri much of the rock waste streams 3 and 4, is used as aggregate  in
road and dam building.

Bedded and vein deposits often require more treatment using crushers and
froth flotation in addition to density separation because of the more
complex assemblage of minerals.  Figure 2-19 is a flow sheet for this  type
of treatment.  As can be seen from the figure, two waste streams are
produced.  The tailings products from  this type of process would consist  of
the siliceous components of the rained  ore.  The  first stage (density)
tailings would be coarser than those from the second stage.  They are  most
often combined and disposed as a single stream.

There are two possible areas of concern from barite production.  The  first
is that barium is one of the eight EP  toxic metals, and  because of  the
nature of the EP toxic test barite tailings may show elevated barium
levels.  Barium sulfate, however, is not soluble  to more  than 5 mg/1  in
                                   2-65

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                       Figure 2-18

                   BARITE FROM RESIDUUM
Barlte Products-
                     Residual Gravels
                             1
                           Size
                         Reduction
                         Screening
                          Vashing
                           Size
                        Separation
Concentration
                  •> (1) Coarse (+5") Vaste
                   •>(2) Washing Tailings
                         Oversize (+7/8")
                         Road and Dam
                         Building
Fine Gravel Road
and Dam Building
                       2-66

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                             Figure 2-19

                      BARITE FROM BEDS AND VEINS





                            Run of Mine Ore
Final Barite Product*-
                                  1
                                 Size
                               Reduction
                               1st Stage
                             Concentration
                               (Density)
                                 Size
                               Reduction
                                  I
  2nd Stage
Concentration
 (Flotation)
                  fr,  (1) 1st Stage Tailing
(2) 2nd Stage Tailing
                                             Tailings
                                               Dam
                          2-67

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water, therefore barite tailings are probably not a major source of barium
in the environment.  The second concern is that barite is often found with
metal sulfides, but there has not been any economic production of metals
and barite as coproducts or byproducts from these deposits.  If
exploitation of these deposits for barite ever commences the waste problems
would be essentially the same as found in metal production.

The waste characteristics from this screening study are summarized in Table
2-10.  Based on this analysis, further study of this industry for potential
regulation under Subtitle C is recommended.
                                   2-68

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                                          TABLE 2-10
                                         BARITE WASTES
Process Waste
Beneficiation of 1) Coarse Waste (+5")
Residual Ores 2) Washing Tailings (Claysj

3) Oversize (+ 7/8")

4) Fine Gravel

NJ
1
£ Beneficiation of Ores 1) 1st Stage Tailing (Fine
from Beds or Veins Barite, Quartz, etc.)
2) 2nd Stage Tailing (Quartz,
etc.)
Possible RCRA Characteristic*
R C I T Comments
N
N

N

N



N

N

N N ? Large rocks
N N ? Due to nature of
test
N N ? Road and dam
building
N N ? Road and dam
building


N N ? Same as 2 above

N N ? Same as 2 above

N - Waste not expected to exhibit this characteristic.
Y - Strong indication that waste vould exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

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                           BITUMINOUS MATERIALS

Bituminous materials consist of a group of hydrocarbon mixtures including
asphalts, asphaltites, mineral vaxes, and pyrobitumens.  Production of
asphalts and asphaltites totaled 1.6 million short tons in 1979.  Native
asphalt is produced by one operation in Texas and asphaltites are produced
by three operations in Utah.  There is no information on production rates
for mineral vaxes or pyrobitumens.  The four classes of bituminous
materials are mined and processed differently and are discussed separately
below.

Asphalts

Native asphalts occur in the United States as deposits of bituminous
sandstone and limestone.  The most extensive deposits are Kentucky, Texas,
Oklahoma, Louisiana, Utah, Arkansas, California, and Alabama.  Current
production is confined to one operation in Texas.  Rock asphalt is
primarily used for paving, with specialty uses in flooring, roofing, and
waterproofing.

Today, native asphalts have largely been replaced by petroleum-refined
asphalt.  Commercial use of the native product is limited to areas where  it
is abundant and easily mined.  The bitumen content of native rock asphalt
ranges from 3 to 15 percent.

Mining of asphalt begins with removal of the overburden.  The deposit  is
blasted, crushed, graded, and blended.  Blending assures a bitumen content
in the final product of 6.5 to 7.5 percent.  The mining operations do  not
consist of any chemical processes and there are no known wastes generated
(Figure 2-20).
                                  2-70

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                        Figure 2-20

                  NATURAL ASPHALT PROCESSING
Asphalt Products *-
                         Rock Asphalt
                              1
                             Size
                           Reduction
                            Grading
Blending
                            2-71

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Asphaltites

Asphalt!tes are bituminous materials used in specialized markets including
automotive sealants, oil veil drilling, foundaries,  varnishes,  paints,
inks, coatings, and flooring materials.  There are tvo types of asphaltites
occurring in the United States:  gilsonite and grahamite.   Grahamite is no
longer mined and has not been used in many years.   Gilsonite is known to
occur in one deposit in the United States that extends from 5 miles east of.
the Colorado border to 60 miles vest into Utah.

Asphaltites are hydraulically mined by some producers since they produce an
explosive dust when mechanically mined.  Water jets or water flooded rotary
cutters are used to produce a slurry which is collected and pumped to a
surface preparation plant.  The material is graded,  packaged, and shipped.
It is not clear whether dewatering occurs in the surface preparation plant
or whether fines are produced during grading operations.  The wastes from
this processing could be ignitable.

The largest producer of gilsonite, the American Gilsonite Company (AGC)
uses air chipping hammers to break up the gilsonite and a vacuum airlift
system to transport the broken material to processing on the surface at a
central plant.  The flow sheet for that plant is shown in Figure 2-21.
Processing consists of drying, screening and bagging.  Some gilsonite is
pulverized prior to shipment.  Both pulverized and unpulverized gilsonite
is shipped in bulk as well as in bags.  The primary waste from  this plant
is the rock removed by the vibrating screen which is not expected to
exhibit any hazardous characteristics.

Mineral Uaxes

Mineral waxes do not exist in the United States as a natural substance,
and, therefore, must be extracted from lignite or cannel coal.  Although
coal exists in many parts of the United States, the only known  production
                                  2-72

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                          Figure 2-21

                      GILSONITE PROCESSING
Gilsonite  Products
                        Gilsonite Slurry
                           _L
Grading
Possible  Waste Fines
                            FIGURE  2a

                    American Gilsonite Company
                        	Flowsheet	
                                            Silos (l.SOO toni «ach)
Or* 
-------
occurs in California.  The extraction product, known as Montan Wax, has a
very limited use in paints, wood fillers, floor polish, rubber mixtures,
and candles.

The processing consists of solvent extraction from coal (Figure 2-22).
Probable vastes include spent solvent and spent coal.  There is no
information available on the quantities or characteristics of these vastes.
Waste management methods for this industry are not known.

Pyrobitumens

Pyrobitumens are mined mainly in Utah.  They have limited uses in rubber,
paints, varnishes, and insulating and waterproofing compounds.

Processing consists of cracking in a still, recondensation and grading.
Possible waste products include waste catalyst and still bottoms (Figure
2-23).  The management methods, quantities, and properties of these wastes
are not known.

Production of naturally occurring bituminous materials is fairly low, due
to low cost of petroleum refining substitutes.  The volumes of waste
materials will be minimal, although some of them may be fairly hazardous.

Based on the above analysis, further study of these industries, with  the
exception of native asphalt, for regulation under Subtitle C is
recommended.
                                  2-74

-------
                   Figure 2-22

          MINERAL (HONTAN)  WAX PRODUCTION
              Lignite or Cannel  Coal
Montan Wax
 Solvent
Extraction
->(1) Spent Solvent
  (2) Spent Coal
                     2-75

-------
                    Figure 2-23

               PYROBITUMEN PROCESSING
Pyrobilumen
Products «-
                    Pyrobi tumens

                         1
                      Cracking
                        Still
                    Condensation
Grading
                -fr (1)  Waste Catalyst
                   (2)  Still Bottoms

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                              BORON MATERIALS

Boron, commonly found in the mineral tincal, has found many uses in
industry.  Boron compounds, are used in glass making,  textile fibers,
enamels, cleaners fertilizers, insulation and many other products.   The
United States is the largest single producers, with slightly more than 502
of total world production.

Borates are produced both by mining solid minerals and by precipitating the
desired compounds from desert lake brines.  There are two primary mining
areas in the US, Boron, CA and the Death Valley, CA area.  Borates are
produced from brines at Searles Lake, CA.

Ores at Boron, CA are selectively mined, crushed and stockpiled for
processing.  The ore is principally tincal (sodium borate), which is easily
soluble in water.  As shown in the flow sheet, Figure 2-24, the ore  is
crushed to less than 1" lumps and then the tincal is dissolved  in hot,
weak, recycled borax solution, leaving some clay and few other  insoluble
impurities (Waste 1).  The insolubles are then separated from the solution
and the clarified liquor is fed to crystallizers.

The crystals of sodium borate are separated from the weak solution which  is
recycled to the dissolution step.  The crystals are dried and may be sold
as is, as borax, or treated to produce other materials.  Some of the ore  is
reacted with sulfuric acid to produce boric acid and leaves sodium sulfate
as a waste, which is not expected to exhibit any hazardous characteristics.

Figure 2-25 shows the flow sheet for processing Death Valley ores
containing colemanite (calcium borate) which  is insoluble  in water.  This
material is crushed to less than 3/8 in., then washed  to remove clay (Waste
1 in Figure 2-25).  The clay  free material  is ground  further, and  then
concentrated by froth flotation producting a saleable  product and  limestone
tailings (Waste 2 in Figure 2-25).  This borax product  is  then  dried and  a
portion bagged for sale.  The rest is calcined and  the  calcine  is  then

                                  2-77

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                    Figure 2-24

               BORATE ORE PROCESSING

                 BORON CALIFORNIA
     Borax ^
                Ore from Stockpile
                        I
                       Size
                     Reduction
                    Dissolution
                   Solid/Liquid
                    Separation
Crystallization
                          Waste Clay
               BORIC ACID PRODUCTION
                Ore from Stockpile
      Sulfuric,
        Acid
      1
                   Acidf icaMon
Boric Acid
Crystallization
CD  Sodium Sulface
                       2-78

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                        Figure 2-25

                    BORATE  ORE PROCESSING

                   DEATU VALLEY CALIFORNIA
 Borate Products-
Calcined Borate
Product
                        Ore from Mine
                             i
                            Size
                          Reduction
                           Washing
                            Size
                          Reduction
 Flotation
Calcination
                 -Ml) Clays
•> (2)  Limestone Tailings
-£(3)  Borate  Fines  (-45u)
                         2-79

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bagged for sale.  Both the drying and calcining processes produce a fine
borax dust which is a waste product (Waste 3 in Figure 2-25).  This plant
is currently inactive.

Borax production from the brines of Searles Lake is carried out by one of
two processes (both shown in Figure 2-26).  In the first process, carbon
dioxide gas from lime kilns or boiler flue gases is bubbled through the
brine.  Sodium bicarbonate is precipitated.  The brine is then neutralized
and cooled in vacuum crystallizers producing borax crystals.  Further
cooling produces sodium sulfate.  The borax crystals are dewatered and
dried to make borax products.  The other process is an evaporation process
(Figure 2-27) which first produces crystals of potash (potassium chloride).
The remaining solution is then fed into borax crystallization tanks.  The
borax crystals are then filtered washed redissolved and recrystallized.
These crystals are then dried giving the final products.

Boric acid is also made from the brines by a solvent extraction process
(Figure 2-28).  In this process the brine is mixed with a kerosene solution
of a chelating agent which will pull the borate from the brine.  The
organic solvent is then separated from the brine and mixed with an aqueous
(water based) sulfuric acid solution containing no borax.  The borates then
go into the aqueous phase.  After separating the kerosene, the aqueous
material is filtered with activated carbon to remove all traces of the
organic solvent.  The resultant boric acid solution is evaporated and
crystallized to produce the final product.

This initial study did not reveal much detailed information about  the
wastes from these processes.  There are no clearly hazardous wastes
produced,  but the potential does exist (Table 2-11).

Based on the above information, further study of this industry  for
regulation under Subtitle C is recommended.
                                  2-80

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                            Figure 2-26

                      BORATE DRINE PROCESSING

                      SEARLES LAKE CALIFORNIA
                        Catenation Process
Sodium Bicarbonate
             Borax
    Sodium Sulfate*-
                               Brine

                                1
                            Carbonation
 Solid/Liquid
  Separation
 Crystallizer
Crystallization
                                2-81

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                       Figure 2-27

                   DORATE DRINE PROCESSING

                   SEARLES LAKE CALIFORNIA
                     Evaporation Process
Potash (KCl)
  Borax Product
                            Brine
                              1
                           Cooler
Solid/Liquid
 Separation
                            Box-ax
                       Crystallization
                             1
Solid/Liquid
 Separation
                            2-82

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                   Figure 2-28

               BORIC  ACID PRODUCTION

              SEARLES LAKE CALIFORNIA
Brine To 4	
Further Processing
Boric Acid 4-
                       Bi-ine
                      Solvent
                     Extraction
                   Acidification
                      Carbon
                    Filtration
                    Evaporation
                  Crystallization
                           Solid/Liquid
                            Separation
                     2-83

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                                                           Table 2-11


                                                        BORATE  WASTES
to
I
oo
.u
               Process
Vaste
Possible RCRA Characteristic*

R   C   I   T       Comments
Boron, CA Hilling
Boric Acid
Death Valley, CA
Hilling

Searles Lake Brines
1) Vaste Clay
1) Sodium Sulfate
1) Clay Wastes
2) Tailings (Limestone)
3) Borate Fines
1) Waste Brines
N
N
N
N
N
7
N
N
N
N
N
7
N
N
N
N
N
N
N
N
N
N
N
7
               * RCRA  characteristics  are Reactivity, Corrosivity,  Ignitability and EP Toxicity as defined

                 in 40CFR  261  Subpart  C.


               N - Vaste not expected  to  exhibit  this characteristic.

               Y - Strong  indication  that waste vould exhibit  this  characteristic.

               ? - Possibility that waste could exhibit  this characteristic.

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                                  BROMINE

Bromine is a member of the halogen family of elements.   Elemental bromine
is highly reactive and thus it occurs in nature only as bromide compounds.
Bromide compounds are found in sea water, subterranean  brines,  saline
lakes, oil and gas well brines, and evaporate chloride  minerals such as
halite (NaCl), sylvite (KC1), and carnalite.  Five companies in Arkansas
and Michigan produced bromine from subterranean brines  in 1986.

Bromine has a variety of chemical applications.  Ethylene dibromide, an
antiknock additive in leaded gasoline, is the single largest compound
produced with bromine.  Approximately 20 percent of the bromine consumed  in
the United States is used to produce ring-bromined aromatic compounds,
vhich are used as flame retardants.  Other uses include production of
methyl bromide, a soil and space fumigant, and the use of bromine in oil
field fluids.  Total production in 1986 vas estimated to be 325 million
pounds.

Bromine is extracted from brines by chemical oxidation to bromine gas,
followed by air or stream stripping.  The essential steps are:

    1.  Chlorination to oxidize the bromide to bromine;
    2.  Bromine vapor purging by air or stream stripping;
    3.  Condensation of bromine vapor or reaction to form a salt or an
        acid; and,
    4.  Bromine purification.

Liquid wastes are generated by bromine extraction from brines; however,  the
exact nature and quantities of wastes are unknown at this  time.  As  shown
on Figure 2-29, vaste brine is generated by the bromine vapor  removal  stage
of extraction.  These are treated with lime to adjust  their pH and  then  are
reinjected into Class IV disposal wells.  Liquid wastes may also be
generated by the salt and/or acid formation and by  the bromine purification
                                    2-85

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                          Figure 2-29

                 BROMINE EXTRACTION PROCESSES





                       Brine from Veils
Bromine Products-
Bromine Products**-
                         Chlorination
                         Bromine Vapor
                           Extraction
                         Condensation
Purification
  Reaction
                     (1) Liquid Vastes
                         (to disposal veils)
                     (2) Liquid Vastes
>(3)  Liquid  Vastes
• (4)  Liquid  wastes
                             2-86

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processes.  There is a possibility that these wastes could be corrosive or
reactive due to the nature of the product (Table 2-12).

Based on this analysis, further study of the bromine industry for potential
regulation under Subtitle C is recommended.
                                   2-37

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                                                        Table 2-12

                                               BROMINE PRODUCTION UASTES
            Process
                        Vaste
Possible RCRA Characteristic*
R   C   I   T       Comments
KJ
I
CO
GO
            Bromine Vapor Removal

            Condensation

            Bromine Purification

            Reaction
                        1. Vaste brine

                        2. Process waste

                        3. Purification waste

                        4. Liquid Waste
        N   N

        N   N

        N   N

        N   N
Bromine, chlorine

Bromine

Bromine
* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined
  in AOCFR 261 Subpart C.

N - Vaste not expected to exhibit this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

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                                   CLAYS
The clay industry can be broken down into three segments,  by general
composition.  These are (1) bentonite and fuller's earth,  (2) kaolin,  ball
clay and refractory clays, and (3) miscellaneous clays and shale.   Vhile
these categories are based on clay type, processing and uses are roughly
similar within each group.  Annual production is estimated to be 5 million
short tons for bentonite and fuller's earth, 10 million short tons for
kaolin, ball clay and refractory clay and 23 million short tons for
miscellaneous clays and shale (1986).

Bentonite is a term based on mineral type and fuller's earth is a term
based on use.  They are grouped as an industry segment because fuller's
earth also consists of non-swelling bentonite.  Bentonite is primarily used
in drilling muds for oil exploration.  This segment of the clay industry
also provides materials for absorbent granules, iron-ore palletizing, and
foundry sand binding.  The term fuller's earth is applied to clays used in
processing oils and fats (oil refining, filtering, clarifying, and
decolorizing).  There are many other minor uses of these clays.  Processing
is straight forward.  The clay is selectively mined, dried, ground  to size,
and sometimes blended to give the desired properties.  There are no waste
products and fugitive dust emission would be  the most significant problem.

The second industry segment consists of materials containing Kaolin, a  clay
that gives the material good forming and firing characteristics needed  for
making porcelain vare, fire brick, and other  such items.  Kaolin in the
highest grade has a clean white color and is  probably the most highly
processed.  Ball clays are not white but have a light color and are
otherwise the same as kaolin.  Refractory clays are somewhat cruder, with
classification being based on firing and high temperature characteristics
with no regard to color.
                                  2-89

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Kaolin has the most complex processing flowsheet as seen in Figure  2-30.
Selective mining is practiced so that little if any vaste material is
produced at  the plant.  The clarified clay is used in a host of products.
The only area of potential generation of a vaste of concern is the leaching
(brightening, whitening) step which uses acids, ozone or strong reducing
agents (hydrosulfite) to remove the iron-compounds that color the clay.  If
the liquid from this step is discharged it could present a potentially
hazardous waste.  Ball and refractory clays are not normally processed to
this extent.

The final segment of the clay industry is a catch-all for everything that
doesn't fall clearly into either of the above categories.  Much of the
clays in this category are used in low value, high volume applications such
as brick, drain tile, vitrified pipe, quarry, flue and roofing tile,
pottery, and stoneware.   Processing is minimal due to the low value and
most is used as mined near the source.  There would be little or no waste
from this segment of the industry.

Table 2-13 is a summary of the waste characteristics from this screening
industry.  Based on the analysis above, only the bleached kaolin segment of
the clay industry is recommended to be further studied for potential
regulation under Subtitle C.
                                    2-90

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                             Figure 2-30

                      KAOLIN PROCESSING FLOWSHEET
Coarse Clay Products
  Fine Clay Products
                           Kaolin Suspension

                            	1
                               Blending
    Size
 Separation
                               Bleaching
Solid/Liquid
 Separation
Bleaching Wastes
                                2-91

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                                                       Table 2-13

                                                      CLAY WASTES
                                                                       Possible RCRA Characteristic*
            Process                 Vaste                              R   C   I   T       Comments


            Kaolin Bleaching        1) Waste Liquor (acid, ozone,      N     ?   N   N
                                       reducing agents
            * RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity  as  defined
M             in 40CFR 261 Subpart C.
i
vO
10           N - Waste not expected to exhibit this characteristic.
            Y - Strong indication that waste vould exhibit this characteristic.
            ? - Possibility that waste could exhibit this characteristic.

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         COAL:  BENEFICIATION, GASIFICATION,  LIQUEFACTION;  COKING

Coal Beneficiation

Coal beneficiation (washing or cleaning) is done to remove undesirable
materials from a mined coal.  The primary goal is to remove ash-forming
materials such as silicate shales also called bone or slute.   A secondary
benefit, which is being actively studied for future improvements, is the
removal of sulfur-bearing materials, mainly iron pyrite.

Most coarse coal cleaning uses the difference in density between coal and
its contaminants to separate them.  Both the ash-forming materials and the
iron pyrites are denser than coal.  Density separating devices such as
jugs, Humprey's spirals, shaking tables, sink-float machines, and dense
medium cyclones are used for coarse coal cleaning.  The waste from this
process, coal refuse, generally retains some fuel value and research has
been done to exploit it as a fuel.  Most is disposed in piles.  The pyrite
content causes acid formation when in contact with surface or ground
waters.  Although coarse coal refuse can be burned and acid can be formed
in the refuse piles, it is doubtful that coal refuse will exhibit Subtitle
C hazardous characteristics.

Fine coal cleaning has the same objectives as coarse coal cleaning and can
use some of the same types of equipment.  In addition, fine coal can be
cleaned by froth flotation.  The characteristics of the wastes from fine
coal cleaning are expected to be the same as from coarse coal cleaning.

Coal Liquefaction

Many coal liquefaction processes are currently in various stages of
research and development but none have reached commercial production and
therefore are not addressed by this study.
                                  2-93

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Coal Gasification

There is only one commercial coal gasification plant of sufficient size to
be addressed by this report.  This is the American Natural Gas plant,  a
Department of Energy facility at Beulah, North Dakota.   A complete report
on that plant will be written when the necessary information is received
from the EPA.
Coke
Coke is the solid, porous, carbon product of the destructive distillation
of coal.  The major use of coke is in blast furnaces used to produce pig
iron.  It is  Iso used as a fuel in other varied applications.

Two types of processing facilities are operated in the U.S., beehive and
byproduct plants.  There were only 3 beehive plants operating in the U.S.
in 1986, and 46 byproduct plants in 15 states (Nielsen, 1986).  Twenty-six
of the plants were owned and operated by steel companies.  It is estimated
that 90X of coke production is for the iron and steel industry.  Coking
operations are mainly in the eastern U.S., with Alabama, Indiana, Ohio, and
Pennsylvania plants numbering over half of the total.

Beehive plants involve a beehive oven that heats blended bituminous coal in
the absence of oxygen.  Volatile organic compounds are driven off of the
coal and released to  the atmosphere.  The coal is converted to coke in  the
oven, cooled by quenching with water resulting in a weak ammonia liquor
which will contain a mixture high in two classes of toxic compounds,
cyanides and phenols, and sent to a crushing, screening, and  blending
operation.  Portions of the quenching water are reused, with  the remainder
typically treated prior to discharge to surface waters.  The  fines  from
screening, or coke breeze, are usually used as feed stock in  iron ore
sintering or pelletizing, and as "inert" material in  foundry  coke
manufacture, electric smelting, or chemical manufacture.  The  process  flow
diagram for the operation is shown in Figure 2-31.
                                   2-94

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                             Figure 2-31
                         BEEHIVE COKING PROCESS
                                  Coal
                                 A.
                                  Coal
                                Blending
Air Pollution
Control Device
Water-
Quenching
 Station
->Vastewater
    NX
Vastevater
   or
Air Pollution
Control Dust
                 Coke
                Crusher
                                                Screening
                                                Station
                                                  V
                                                  Coke
                                   2-95

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Byproduct plants operate on similar principles, but were developed in the
late 1800's to recover some of the organic compounds released to the
atmosphere in a beehive operation.  The process is illustrated in Figure
2-32.  The gases and vapors produced in the coking ovens are treated in a
chemical recovery plant.  The gas is initially cooled by spraying it with
flushing liquor.  Tar that is present in the gas condenses and is collected
with the liquor.  The liquor/tar mixture is sent to a decanter for
separation.  The liquor is partially recycled to the scrubber, with the
rest going to an ammonia recovery unit.  Gases from the scrubber flow
through the primary cooler where additional tar is removed.  Liquid from
the primary cooler is sent to the decanter and recycled.  An exhauster then
sends the gas to an electrostatic precipitator for residual tar removal.

In older plants, the gas flows to an ammonia recovery unit.  Ammonium
sulfate crystals are separated from solution and dried.  The gas is then
sent to the final cooler, a direct contact spray system, that condenses
naphthalene with the spray water.  The naphthalene is then skimmed from  the
water in a sump.  Some plants use an oil in their spray system, then
recover the naphthalene from the oil by steam stripping.

Modern plants no longer are designed to recover ammonia.  After naphthalene
removal, the ammonia is removed from the gas using a recirculating aqueous
solution.  A still volatilizes the ammonia from solution and  the
concentrated ammonia vapor is sent to the combustion furnace  for
incineration.

In either older or more modern operations, the gas is then sent  to a  light
oil scrubber, where aromatic hydrocarbons are recovered.  The crude light
oil from the scrubber contains approximately 70% benzene, 15% toluene,  8%
xylene,  and 1% higher homologues, and is usually sold for further
processing.  The gases still contain hydrogen sulfide.  Since the gas  is
sold as a fuel, hydrogen sulfide must be reduced to prevent  formation  of
sulfur dioxide during combustion.  A number of methods  are used  to separate
                                   2-96

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                               Figure 2-32

                         BYPRODUCT COKING  PROCESS
                      Gas
Flushing Liquor
   Decanter
      \'
  Dehydrator
  Ammonia
  Removal
   Phenol
  Extractor
    Waste
    Water

Ammonia
Vapor
     Ammonia
      Still
                    Primary
                    Cooler
                    Exhauster
                       _w
                   Electrostatic
                   Precipi tator
Ammonia to
Combustion Furnace
for Incineration
                       _V
                      Final
                     Cooler
                     Ammonia
                     Absorber
                       _V
                     Light Oil
                     Scrubber
                        \f
                       Hydrogen
                     Sulfide Srubber
                         Coking
                          Gas
                                                    Quenching
                                                     Station
        Coke
       Crusher
                                                     Screening
                                                      Station
                     > Coke
                      Breeze
                                                       T
                                                        Coke
Sump
Naphthalene
                                              Vaste
                                              Water
                                     2-97

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 the hydrogen sulfide.  Once separated from the coifing gas, the hydrogen
 sulfide  is converted either to elemental sulfur or sulfuric acid.
 The wastewaters from the various coolers and scrubbers and from coke
 quenching contain ammonias, phenols, and other organic compounds.  Lime or
 caustic  is added to the solution, then the wastewater is fed to an ammonia
 still.   The ammonia vapors are either converted to ammonium sulfate or sent
 to the combustion furnace for incineration.

 Removal  of phenols is treated differently in old and modern plants.  Older
 plants remove phenols from the wastewater by solvent extraction and recover
 them as  sodium phenolates by contact with sodium hydroxide.  In more modern
 plants,  the wastewater is treated using an activated sludge process to
 remove organics.  After treatment,  the wastewater is usually discharged to
 surface  waters.

 Vastes produced from beehive coking operations may include waste quenching
 water, air pollution control dusts, or scrubber water.  The wastewaters are
 usually  treated prior to discharge  to surface waters as allowed under a
 discharge permit.  The disposition of any air pollution control dusts is
 unknown.

 Byproduct coking plants produce waste waters from coolers, scrubbers, and
 coke quenching.  The vaste matters are generally treated prior to  permitted
 discharge to surface waters.  The treatment processes may generate solid
 wastes such as sludge from an activated sludge plant or spent solvent from
 the extraction of phenols from the wastewater.  Waste management methods
 for these materials are not known.

 CONCLUSIONS

 The coal washing industry does not generate wastes with hazardous
 characteristics (Table 2-14).  Coal liquefaction is not yet a commercial
 process  and information is needed to develop a report on  coal gasification.
The coking industry generally reuses many byproduct materials.   However,
                                   2-98

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                                                       Table 2-14

                                                      COAL WASTES
            Process
Vaste
Possible RCRA Characteristic*
R   C   I   T       Comments
NJ
I
10
            Coal Washing

            Coking

              Quenching

              Coke Gas Treatment
Coal Refuse
Coke Quenching Water

Flushing Liquors
Cooling Tower Blovdovn
              Vastevater Treatment  Sludge

              Phenol Extraction     Spent Solvent
N   N   N   N
N   N   N

N   N   N
N   N   N
                                   N    N

                                   N    N
        N   ?

        ?   N
Can burn,
Generates Acid
Never Plants Only

Older Plants Only
            * RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined  in
              40 CFR 261 Subpart C.

            N - Waste not expected to exhibit  this characteristic.
            Y - Strong indication that waste vould exhibit this characteristic.
            ? - Possibility  that waste could exhibit  this characteristic.

-------
due to the size of the coking industry, further study for possible
regulation under Subtitle C is recommended.
                                  2-100

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                                 FELDSPAR

Feldspar a.re the most abundant minerals of the igneous rocks and are
represented by three silicate minerals which,  if pure, would be represented
as microcline or orthoclase (KAlSi,Og); albite (NaAlSi,Og);  anorthite
(CaAl,Si-00).  Certain terms are utilized to describe the ores of feldspar.
     i.  f. O
Aplite contains titanium and feldspar minerals and is mined  and
beneficiated in one location in Virginia.  Alaskite is a distinctive rock
type found near Spruce Pine, North Carolina, and is a major  feldspar
source.  This ore is relatively coarse-grained and granitelike.  Graphic
granite is a pegmatite rock predominant in K-spar (KAlSi^Og) with quartz as
a secondary mineral.  Pegmatite is a widely distributed, coarse-grained
igneous rock from which potash feldspar is obtained.  Perthite is a
microscopic intergrowth of plagioclase in K-spar found in graphic granite
and in pegmatites.  Feldspathic sand can occur either naturally or can be
a processed mixture of feldspar and quartz.

Feldspar is utilized in the glass industry, ceramic industry, and as
filler material in paint, urethane, and acrylics.

Annual production is estimated to be with 735,000 short tons  (1986).  The
state of North Carolina accounted for about 70 percent of all domestic
feldspar production.  The state of Connecticut was second in  production,
followed by Georgia, California, Oklahoma and South Dakota.

Pegmatite and alaskite feldspar ores are mined by conventional open  pit
methods.  First, the overburden is removed, followed  by drilling and
blasting on twenty to forty foot benches.  Refining of  feldspar ores  is
primarily by froth flotation.  This process consist of  crushing, grinding,
screening, and desliming the raw material.  Next,  the micaceous minerals
are then removed with amine as the collector  in an acid environment  (pH=3)
with pine oil and fuel oil.  After devatering the  feed  to remove reagents,
the pH is lowered to 2 to 3 by sulfuric acid and  the  feldspar is refloated
                                 2-101

-------
with petroleum sulfonate, as as collector, to remove iron-bearing minerals.
Water is removed from the flotation concentrate and the feldspar is
separated from quartz in flotation cells utilizing hydrofluoric acid and
amine as a collector, at a pH of 2-3.  This feldspar float concentrate is
dewatered using drain bins, vacuum filters, or centrifuges, and lastly
dried in rotary dryers.

Although the solid wastes are largely inocuous minerals, these minerals may
contain flotation reagents whose characteristics require further
investigation (Table 2-15).

Based on this analysis, further study of the feldspar industry,
particularly froth flotation tailings, for potential regulation under
Subtitle C is recommended.
                             2-102

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                                                          Table 2-15

                                                 FELDSPAR PROCESSING UASTES
o
LJ
               Process
Waste
Possible RCRA Characteristic*
R   C   IT       Comments
Deslining
Froth Flotation


Devatering
1.
2.
3.
4.
5.
Waste Slimes (Clays)
Mica Tailings
Iron Tailings
Quartz Tailings
Uastevater
N
N
N
N
N
N
7
7
7
N
N
N
N
N
N
N
N
N
N
N

Low

operating
pH of process
(pH

=2+03)

               *  RCRA characteristics are Reactivity,  Corrosivity,  Ignitability  and EP Toxicity as defined
                 in  40CFR 261  Subpart C.

               N  - Vaste not expected to  exhibit  this  characteristic.
               Y  - Strong indication that waste would  exhibit  this  characteristic.
               ?  - Possibility that waste could exhibit  this  characteristic.

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                                 FLUORSPAR

Fluorspar (calcium fluoride) is the commercial name for the mineral
fluorite.  The domestic fluorspar industry includes 5 mines and 2 flotation
mills.  Domestic production in 1983 was 61,000 short tons.   Fluorspar is
necessary in most steel and aluminum production processes.   The chemical
and ceramic industries are also significant users of fluorspar.  Fluorspar
is the most important commercial source of fluorine.  It is used as a
fluxing agent in metallurgy and ceramics.  It is the rav material for
hydrofluoric acid which is used to make fluorocarbons, synthetic cryolite
and .other products.  Hydrofluoric acid is also used in the manufacture of
electronic devices.  Fluorspar is generally sold in three grades,
metallurgical (75-85* CaF2), ceramic (90-96* CaF2), and acid (97% CaF2
minimum).

Most fluorspar must be upgraded for marketing.  Metspar is often produced
by hand sorting of high-grade lump crude ore, followed by crushing and
screening to remove most of the fines.  In the case of fluorspar ores of
lower grade and/or ores with relatively coarse interlocking of minerals,
gravity concentration processes are used based on the specific gravity of
3.2 for spar and less than 2.8 for most gangue minerals.

Heavy-media cone and drum separators are particularly effective  in the size
range of 1 1/2 by 3/16 inch, either for producing metallurgical gravel or
for preconcentrating the crude ore for flotation feed.  For the  finer
sizes, the heavy-media cyclone process is frequently used.  Ores as low as
14X CaF2 are being preconcentrated to yield a flotation feed of  40* CaF2 or
more.  Lead and zinc sulfides and barite concentrate with  the  fluorspar to
enrich the flotation feed with these valuable minerals.  In some cases,
washing plants are also used prior to flotation  to  remove  clay or manganese
oxides.
                             2-104

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Ceramic and acid grades of fluorspar are produced by multistage froth
flotation.  Ore from the mine is crushed and ground to proper size.  If
sulfides are present, they are preferentially floated off vith a xanthate
collector, lead sulfide first then zinc sulfide.  Then all the easy
floating fluorspar is removed in a quick pass through a flotation circuit
and sent on to the cleaner circuit; the tailings are discarded.  The
middling product is reground to separate the more finely interlocked grains
of fluorspar and gangue, and passed through one or more cleaner circuits.
The final products generally comprise an acid-grade concentrate and in some
cases one or more concentrates of lower grade, vhich are sold as ceramic
grade, or pelletized and sold as metallurgical grade.  Fatty acids are used
as collectors for the fluorspar.  Quebracho or tannin is used to depress
calcite and dolomite; sodium silicate to depress iron oxides and silica;
and chromates, starch, and dextrin to depress barite.  Cyanide is used to
depress any remaining sulfides.  Lime, caustic, or soda ash can be used  for
acidity control.  Flotation temperatures range from ambient to 80°C.

A typical flowsheet for fluorspar processing, as shown in Figure 2-33, has
two main waste streams.  The density separation tailings waste stream  1
will be primarily siliceous rocks, but will contain some fluorspar, which
is fairly resistant to weathering, but it is soluble enough in water that
fluorides could be excessive in run off from piles.  The froth flotation
tailings vaste tvo vould also contain fluorides and in addition could  have
toxic metals, because lead and zinc sulfides, and barite (barium sulfate)
commonly occur with fluorite.  While many operations produce  these as
coproducts, the separation processes would leave some in the  tailings.

Hydrofluoric acid (HF) is produced by reacting bone dry  fluorspar  with
concentrated sulfuric acid at high temperature.  The HF  is removed as  a
vapor and calcium sulfate is left as a solid.  Calcium sulfate itself  is
not hazardous but there is probably residual fluoride in the  residue  that
should be controlled.
                                 2-105

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                             Figure 2-33

                         FLUORSPAR PROCESSING
Hand Sorting Products-
  Coarse Concentrates-
      Fine Flotations-
      Concentrates
                                  Ore

                                 1
                                 Size
                               Reduction
   Hand
  Sorting
                                 Size
                               Reduction
  Density
 Separation
                                 Size
                               Reduction
 Flotation
Separations
Tailings
Flotation Tailings
                                2-106

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Table 2-16 summarizes waste characteristics from this  screening study.
Based on this analysis,  further study of this industry for  potential
regulation under Subtitle C is recommended.
                                  2-107

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                                                     Table 2-16
                                                 FLUORSPAR WASTES
O
00
Process
Fluorspar Beneficiation

Hydrofluoric Acid Production
Waste
1) Gravity Tailing
2) Flotation Tailings
1) Calcium Sulfate Residue
R
N
N
N
C
N
N
N
I T
N ?
N ?
N N
Comments
fluorides
fluorides
fluorides
* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined  in
  40CFR 261 Subpart C.

N - Waste not expected to exhibit this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

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                                  IODINE
Iodine is a member of the halogen family of elements,  and  because of  its
reactivity, occurs in nature only as iodates and iodides and  other combined
forms.  Marketed chemical forms of iodine include iodine  (crude and
resublimed), calcium iodate or iodide,  potassium iodide, sodium iodide,  and
numerous organic compounds.  Principal  end uses of iodine  include
photographic chemicals,  food supplements (iodized salt), pharmaceutical
products, and disinfectants.  Two companies produce iodine from
subterranean brines in Oklahoma.  North American Brine Resources treat
brines associated with oil production and Woodward Iodine  uses brines
extracted for their iodine content.

Production of iodine at  Woodward, Oklahoma is by the process  shown in
Figure 2-34.  The first  stage of processing removes hydrogen  sulfide gas
contained in the brine.   This gas is reacted to form sulfur compounds which
are sent to a hazardous  waste disposal  facility.  The second  stage of
processing is a chlorine oxidation to convert iodide to iodine.  The iodine
is then removed from the brine by air vapor stripping (air-blowout).  The
waste brine is treated with lime to adjust pH and is reinjected into Class
IV disposal wells.  The  iodine vapor is absorbed by a solution of
hydroiodic and sulfuric  acids.  Sulfur dioxide is added to reduce  the
absorbed iodine to hydroiodic acid.   Most of the solution is recirculated
to the absorption tower, but a bleed stream is sent to a reactor  for iodine
recovery.  In the reactor, chlorine is added which oxidizes and liberates
the iodine which precipitates and settles out of solution.  The settled
iodine is filtered to remove waste liquor and melted under a layer of
concentrated sulfuric acid.  The melted iodine is then solidified  either as
flakes or ingots.  The management practice  for the waste bleed  liquor was
not identified.

Iodine recovery from oil production brines  probably uses the process
described above, with the exception of the  hydrogen sulfide removal, which
                                     2-109

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                         Figure 2r34

                     IODINE EXTRACTION

                       Woodward,  OK
Iodine Product<
                     Brine from Veils
 H2S Removal
                            Air
                         Stripping
                      Sulfur Dioxide
                         Treatment
                        Absorbtion
                           Tower
                               Bleed
                       Precipitation
                       with Chlorine
                         Filtration
Melting under
Sulfuric Acid
                                                Sulfur Compounds
                         Waste Brine
                    •(3) Waste bleed liquor
                         Filtrate Waste
                        2-110

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may not be necessary.  No specific information was readily available.   At
least one of the wastes from iodine production is presently managed as
hazardous, and others have the possibility of exhibiting hazardous
characteristics (Table 2-17).   Therefore,  further study of this industry
for possible regulation under subtitle C is recommended.
                                  2-111

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                                                           Table 2-17

                                                  IODINE PRODUCTION WASTES
               Process
                        Waste
Possible RCRA Characteristic*
R   C   I   T       Comments
N>
I
               Hydrogen Sulfide
               Removal
                        1. Sulfur Compounds
               Air Stripping of
                Iodine from Brine
                        2. Waste Brine


Iodine Precipitation    3. Liquid Waste
?   ?   N   N
?   ?   N   N
                                                                          ?   ?   N   N
Hazardous Waste
Disposal Class V
disposal wells

Chlorine, Iodine
                  Acids,  Iodine,
                  Chlorine
               * RCRA characteristics are Reactivity,  Corrosivity,  Ignitability and EP Toxicity a.s  defined
                 in 40CFR 261 Subpart C.

               N - Waste not expected to exhibit this  characteristic.
               Y - Strong indication that waste vould  exhibit this  characteristic.
               ? - Possibility that waste could exhibit this characteristic.

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                                  KYANITE

Kyanite is a member of the sillimanite family of minerals which are
anhydrous aluminum silicates (Al-O,.Si02).   Kyanite is noted for its
refractory properties.  It represents 10 to 40 percent (balance is
refractory clays or coarser grog material)  of refractory mortars,  cements,
castables, and plastic ramming mixes.  Kyanite deposits that are currently
being exploited are Willis Mountain,  and East Ridge,  Virginia.   Production
data is considered company proprietary.

Excavated kyanite ore is crushed, classified, and concentrated  as shown in
Figure 2-35 to produce a relatively pure kyanite product.  After crushing
and classifying, the ore is deslimed (producing a slime waste,  Waste 1) and
then concentrated in froth flotation cells.  Tailings from the  flotation
cells are further separated in scavenger flotation cells and a  tailing
waste, Waste 2, is ultimately produced.  Tailings will contain  pyrite and
micaeous material.  The pyrite content of these tailings may be high enough
to exhibit hazardous characteristics.

The flotation concentrate is dewatered,(producing Waste 3), dried and
cleaned in a magnetic separator.  The magnetic separator will produce an
acid soluble iron waste (Waste 4), containing iron oxides which would not
be expected to exhibit hazardous characteristics.  Kyanite is further
ground and classified, and some  is calcined  to produce final products.

Wastes from the processing of kyanite  include tailings, waste slimes, and
acid soluble iron as summarized  in Table 2-18.  This analysis leads  to  a
recommendation for further study of kyanite  froth  flotation  tailings  for
potential regulation under subtitle C.
                                  2-113

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                         Figure 2-35

                      RIANITE PROCESSING
Kyanite Products
Calcined Kyanite
                         Kyanite Ore
                              I
                            Size
                          Reduction
                          Desliming
                            Froth
                          Flotation
                          Devatering
                           Magnet ic
                          Seplaration
  Size
Reduction
Calcining
                   (1)  Slime  Vaste
                   (2)  Tailings (Pyrite,
                       Micaceous Material)
                •> (3)  Vaste Vater
                   (A)  Acid Soluble
                       Iron Vaste
                           2- 114

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                                            Table 2-18

                                      KYANITE PRODUCTION
                                                           Possible RCRA Characteristic*
Process                 Waste                              R   C   I   T       Comments


                        1. Slimes (Clay)                   N   N   N   N

Froth Flotation         2. Flotation Tailings (Pyrite,
                           Mica)                           ?   ?   N   N

Devatering              3. Uastewater                      N   N   N   N

Magnetic Separation     4. Magnetic Tailings
                           (Iron Oxides)                   N   N   N   N


* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP.Toxicity as defined
  in 40CFR 261 Subpart C.

N - Vaste not expected to exhibit this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

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                                  OLIVINE

The tvo primary components of olivine are forsterite  (Mg^SiO.)  and  fayalite
(Fe-SiO,).  The mineral is the principal component  of the  rock  dunite.
Dunite deposits exist in the United States in a belt  from  northeastern
Georgia to western North Carolina, in northwestern  Washington,  and  in
southeastern Alaska.  One company, with mines in North Carolina and
Washington, is currently producing olivine in the U.S.

Olivine is a heat resistant material with low expansion qualities.   It  is
used as a slag conditioner in blast furnaces, as a  specialty foundry sand,
in heat storage blocks, as a refractory (heat resistant) material,  and  as
an abrasive.  The use of olivine is closely tied to the hot metal industry.
United States production was 240,000 short tons in  1978.  This  number is
probably much lower now due to the decline in the United States steel
industry.

Beneficiation of olivine can be done by a wet or a  dry process.  In the wet
process (Figure 2-36), the ore is sent first to crushers to reduce the
material to the specified size.  North Carolina olivine is relatively
impure, and must be further processed to produce foundry sand.   After
crushing, fines (<20 mesh) are removed, slurried, deslimed, sized,  and sent
to either concentrating tables or froth flotation.   The plus 20 mesh
materials is sent to a vet rod mill, deslimed, sized, and then sent to
either concentrating tables or froth flotation.  Wastes generated  include
waste slimes from desliming operations, tailings from either concentrating
tables or flotation, and vastewater from dewatering operations.  The
chemicals used in the flotation processes are unknown at  this  time, but  are
probably fatty acids or petroleum sulfonates.  It  is  known  that olivine
ores commonly contain chromite (FeCr-O,) and larsenite  (PbZnSiO^),  so  the
tailings may exhibit hazardous characteristics.  There  is no information on
current waste management methods.
                                  2-116

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                      Figure 2-36

                  OLIVINE PROCESSING
Foundry Sand*-
                      Olivine Ore
                          1
                         Size
                       Reduction
                       Desliming
                     Concentration
                     by Tables or
                    Froth Flotation
                           I
Dewatering
                  •(1) Waste Slimes
                   (2) Tailings
(3) Waste Water
                         2-117

-------
The dry process uses crushers to reduce the material to desired sizes, and
vibrating screens to separate those sites.  The dry process is used on high
grade ores and is not expected to produce wastes with hazardous
characteristics.  Most olivine is produced by the dry process.

Table 2-19 summarizes the information on the waste characteristics in this
industry.  Based on this analysis further study of the tailings from  the
wet froth flotation process for possible regulation under subtitle C  is
recommended.
                                   2-113

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                                                          Table 2-19

                                                 OLIVINE PRODUCTION VASTES
              Process
                        Waste
                                   Possible RCRA  Characteristic*
                                   R   C   I   T       Comments
NJ
I
Desliming

Concentration
(Froth Flotation)
(Tables)

Dewatering
1. Vaste Slimes (Clays)

2. Tailings



3. Vastewater
                                                                         N   N    N   N

                                                                         N   N    N   ?     Possible Pb, Zn,
                                                                                          Cr
N   N   N   N
              *  RCRA  characteristics are Reactivity,  Corrosivity,  Ignitability  and EP Toxicity as defined
                in  40CFR  261  Subpart C.

              N  - Vaste not expci-.ted to  exhibit  this  characteristic.
              Y  - Strong  indication that waste would  exhibit  this  characteristic.
              ?  - Possibility that  waste could exhibit  this characteristic.

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              PHOSPHATE ROCK,  PHOSPHORIC ACID AND  PHOSPHOROUS

There are two primary geographical areas of  production  of  phosphate  rock in
the United States.  The southeast, vith mines in North  Carolina  and
Tennessee is lead in production by Florida vhich is  a dominant world
producer.  Most of the phosphate rock in these areas is in pebble  deposit
combined with clay and some quartz sand.  In the intermountain region,
phosphate rock is produced in Idaho,  Montana, and  Utah.  The deposits here
are beds often overlain by chert (a form of  quartz)  or  carbonates.   Annual
domestic production of phosphate rock is estimated to be 40 million  short
tons (1986).

Pebble deposits in the Southeast do not need the amount of size  reduction
required for the deposits in the Western States.  Washing and  recovery of
fine phosphate by flotation is generally practiced as shown in  Figure 2-37.
The clay slimes waste stream (1) (Table 2-20) is the result of  a size
separation and contains all material finer than about  .1 mm (150 mesh) that
has come into the plant.  The major component is clay with some  fine
phosphate rock and quartz.  It is produced in large volumes and  is a water
slurry containing 2% to 3% solids by weight, this  slurry thickens to 12-152
solids in 2 or 3 years.  There are probably  no RCRA hazardous
characteristics to this waste, but the volume produced  may warrant further
study.  The flotation tailing stream (2) is  similar in  weight  to the dry
slime content and consists of quartz sand which is inert.   It  is usually
pumped into mined cuts for disposal and land reclamation.

About 50X of the intermountain phosphates are main bed  ore that can be used
as mined.  Most of the rest is simply washed and screened, and a small
amount is upgraded by flotation in Utah and Idaho.  Figure 2-38 shows
washing flowsheets for low and high grade ores.  The coarse waste stream
from the low grade ores (stream 5) would consist of overburden and similar
materials that were mixed with the phosphate rock.  It  consists primarily
of siliceous rocks which are inert and  might even be of use as aggregate.
                                2-120

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                            Figure 2-37

              FLORIDA PELLET PHOSPHATE  GENERAL  FLOWSHEET
                            Feed  from  Mine
                               (Slurry)
   Coarse Pebble
   Products (-»-1.2mm)
Fine Product *—
-1.2 mm + .1 mm
                                   i
                                 Size
                               Reduction
                                Washing
                                 (Clay
                                Removal)
Screening
                               Desliming
Flotation
                -»i (1) Clay Slimes (-.1mm)
                       Clay
                       Quartz
                       Very fine Phosphate
                         Rock
(2) Flotation Tailing
    Quartz
                                           Slimes Ponds
                                2- 121

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          Table 2-20
PHOSPHATE PROCESSING WASTES
Possible RCRA Characteristic*
Process
Benef iciation




Phosphoric Acid

Production

Elemental Phosphorous
Production


* RCRA characteristics
N - Waste not expected
Y - Strong indication
Waste
1)
2)
3)
4)
5)
1)

2)

1)
2)

3)
are
to
that
? - Possibility that waste
Clay Slimes (Clay, Quartz)
Flotation Tails (Ouartz)
Coarse Waste (Chert, Gravel)
Lov Grade Waste Slimes (See 1)
High Grade Waste Slimes (See 1)
Phosphogypsum (CaSO. 2H_0)
H i

Fluosilicic Acid

Calcium Silicate Slag
Dry Particulates (Off-gas
Scrubber)
Condenser Water
R C
N**
N
N
N
N
N

N

N
7

N
Reactivity, Corrosivity, Ignitability
exhibit this characteristic.
-
waste would exhibit this characterist
I
N
N
N
N
N
N

Y

N
?

Y
and

ic.

N
N
N
N
N
N

N

N
7

N
EP


T
N
N
N
N
N
N

N

N
7

N
Comments
Large volume




Radioactivity,
Large volume
Potentially
saleable product
Hay be radioactive
May be recycled

Hay be recycled
Toxicity as defined in




could exhibit this characteristic.

-------
                         Figure 2-38

       INTERHOUNTAIN BEDDED PHOSPHATES GENERAL  FLOWSHEETS
   Phosphate Rock
   Product «f	
                            Lov  Grade
                         Run of  Mine  Ore
                                I
                              Size
                            Reduction
                             Washing
Grinding
Desliming
Devatering
                   (3) Coarse (+'/*") waste
                       Chert
                       Gravel
                                            (4)  Waste  Slimes
                                                Clays
                                                Quartz
Coarse (+Y.")
Phosphate Product
   +20 Mesh
   Phosphate Rock
Fine Phosphate
Product
                           High Grade
                         Run of Mine Ore
                                I
                              Size
                            Reduction
 Washing
 Screening
                            Desliming
                            Dewatering
                 -» (5)  Waste  Slimes
                        Clays
                        Quartz
                              2-123

-------
The waste slimes (4) would be similar to the clay  slimes  from  Florida
deposits but it is a low volume stream.   The high  grade deposit  produces
only a waste slime similar to (2) and (4).

Phosphate rock is principally used to make  phosphoric  acid  and only 10% or
less is used to produce elemental phosphorous.   Some of  the phosphate rock
in North Carolina is calcined prior to producing phosphoric acid,   all
phosphate rock in the Western States, if used to manufacture phosphoric
acid, is calcined.

Phosphoric acid is produced near the point  of phosphate  mining in  most
cases, but may be produced near a cheap source of acid,  such as a  smelter,
or a source of Frasch or recovered sulfur.   Figure 2-39  shows  the  steps of
producing phosphoric acid using sulfuric acid,  which is  the most common
acid used in the U.S. to produce phosphoric acid.
A very common mineral in phosphate rock is fluorapatite (Cae(PO.)^F] which
releases hydrofluoric acid when reacted with a strong acid.   This reacts
with any silicates in the rock to form fluosilicic acid which is volatile
and is removed by off-gas scrubbers, creating stream (1).   This stream
would be corrosive and contain fluorides.  Some operations are selling the
fluosilicic acid or sodium silicofluoride as a water fluoridation chemical.
The solid waste (2) resulting from acidulation is gypsum (CaSO,2H20) which
is not a particularly hazardous material, but it contains uranium that
naturally occurs with the phosphate rock.  The possibility of radiation
hazard is made worse by the large volumes of this waste that are produced.
Some attempts have been made to recover uranium from phosphoric acid, but
that is not economically profitable at this time unless old contracts,
written when U,0g was $42 per pound, remain in force.

The amount of electricity consumed in producing elemental phosphorous (6
kwh/pound) tends to cause production to be in areas with cheap power.  The
Tennessee Valley Authority, for an example, was a producer.  The process
uses coke as a reducing agent and silica  fluxes as shown in Figure  2-40.
                                2-124

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                          Figure 2-39
                  PHOSPHORIC ACID TREATMENT
                 Beneficiated  Phosphate Rock
Phosphoric Acid*-
                              I
                            Size
                          Reduction
                         Acidulation
                            With
                        Sulfuric  Acid
Solid-liquid
 Separation
                     (1)  Off Gas Scrubber
                           Liquor
                         Fluorides
                         (Fluosilicic Acid)
-»(2) Phospho-Gypsum
      Gypsum(CaSO,'2H.O)
      (Uranium)
                            2-125

-------
                       Figure 2-40

                 ELEMENTAL PHOSPHOROUS
                    Phosphate Rock
                       (Coarse)
Elemental
Phosphorous •*
(Under Water)
                     Agglomeration
                     Coke
      Flux
                       Electric
                       Furnace
                              Off Gas
                      Paniculate
                       Scrubber
                         (Dry)
 Elemental
Phosphorous
 Condenser
                 -•> (1) Slag Calcium
                       Silicate
                   (2) Particulates
•*-(3) Condenser Vater
                       2-126

-------
Electric furnace production of elemental phosphorous has three vaste
products.  The calcium silicate slag (1) from the furnace may contain
enough uranium to present a radiation hazard, but calcium silicate is
similar to the mineral wollastonite and is probably not hazardous itself.

The dry particulates from the off-gas scrubber (stream 2) include fines
from the feed materials, (coke, phosphate rock,  and silica).  These may be
recycled to the furnace but further characterization is needed if they are
found to be discarded.  The phosphorous condenser water (stream 3) could
pick up fluorides or other soluble contaminants  from the furnace off-gas.
This water may be recycled but, again further characterization would be in
order if it is not.

Based on the above analysis, further study of this industry for regulation
under Subtitle C is recommended.
                                   2-127

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                                  SILICA
Silica, or quartz, is one of the harder,  more abrasive,  and  chemically
resistant minerals found in nature.   The  mineral  is  composed of  silicon
dioxide (Si02) vhich occurs in several crystalline phases  imparting
different physical properties of and uses for the mineral.   Aside from
aggregate production (sand and gravel),  silica is used largely as a
refractory for blasting sands, in the ceramics industry, and in  the
production of glass (largest non-aggregate use).   Foundry  and molding sand
(refractory) and glassmaking account for  20 million  tons/year of silica
use.  These uses dictate stringent chemical specifications for silica
(i.e., specified tolerances for other naturally occurring  metals).   Silica
is generally extracted from sandstone and quartzite  formations by open pit
or underground mining operations, or by dredging or  excavation of sand
deposits.  Approximately 75 percent  of the silica production is  east of the
Mississippi, near large population centers, vhere there is the largest
demand for the product.  In the vest, California and Nevada are production
leaders for silica.

As shown in Figure 2-41, once extracted,  silica is generally subjected to
three stages of crushing, followed by washing, concentrating, drying,
screening, and possibly pulverization to produce silica flour.  The
washing/scrubbing stage will produce a liquid waste  (waste 1) (Table 2-21)
consisting of clay or iron surficial impurities vhich are  unlikely to be
RCRA hazardous.  Other co-occurring detrital minerals may  be removed by
separation techniques.  If separation is by magnetic or electrostatic
means, the waste is not likely to be RCRA hazardous (waste 2); however, the
froth flotation process is carried out at a pH between 2 and 3 and the
flotation tailings (streams) might be corrosive.  After separation,  the
silica is dried by steam static, rotary kiln, or  fluid-bed  type
incinerators, and is subsequently cooled and screened  to produce a product
with the required size specification.
                                      2-128

-------
                        Figure 2-41

                    SILICA PRODUCTION
Coarse Product
  Silica Flour
                       Silica Ore
                            I
                          Size
                        Reduction
                         Washing/
                         Scrubbing
                        Magnetic  or
                       Electrostatic
                        Separation
                            or
                           Froth
                         Flotation
Solid-Liquid
 Separation
    Size
  Reduction
                  -> (1) Waste  Fines
                  -» (2)  Tailings
                         Flotation Tailings
                         2-129

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                                                         Table 2-21

                                                           SILICA


                                                                          Possible  RCRA  Characteristic*
               Process                 Waste                              R   C  I  T       Comments
               Silica Preparation      1.   Vashing/Scrubbing  Overflow
                                           (Clays)                        N     N   N   N
                                       2.   Magnetic/Electrostatic
fJ                                          Tailings                       N     N   N   N
^                                      3.   Flotation Tailings             N     ?   N   N
<->                                      4.   Dryer Stack Losses
°                                          (fine silica)                   N     N   N   N


               * RCRA characteristics are  Reactivity,  Corrosivity,  Ignitability  and EP Toxicity as defined
                in  40CFR 261 Subpart C.

               N - Vaste not  expected to exhibit this  characteristic.
               Y - Strong indication that  waste would  exhibit this  characteristic.
               ? - Possibility that  waste  could exhibit this  characteristic.

-------
Based on the above analysis,  further study of this industry,  particularly
the flotation separation,  is  recommended for regulation under Subtitle
C.
                                 2-131

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                                 ASBESTOS

Asbestos is the generic name for a group of fibrous silicate minerals.
Chrysotile, the fibrous variety of the mineral serpentine (a magnesium
silicate), accounts for about 942 of world asbestos production and all of
U.S. production.  The amphibole series minerals crocidolite, amosite,
anthophyllite, tremolite and actinolite make up the rest of world
production.  Asbestos is used primarily as a fiber, in various lengths.
There are three active asbestos mines in the U.S.   Two are in California
and one is in Vermont.  Total production from all  three was estimated by
the U.S. Bureau of Mines at 50,000 short tons in 1986.

The lengths of the asbestos fibers are the property for which they are
sorted.  Most processing is done dry and air is used as a carrying or
sorting medium.  The general flowsheet (see Figure 2-42), consists of
crushing followed by many size separations.  As shown in the figure, there
are two main waste streams from the processing.  Stream 1 is coarse rock
from sorting.  This would be lumps larger than 2"  which show no significant
veins of asbestos.  This waste would still be contaminated either by dust
or very small veins of asbestos fiber.  Stream 2 would consist of fine
rocks and dust.  This stream would also be contaminated with asbestos
fiber.  One plant in California processes asbestos in water.  This plant
would have similar waste streams to those found in dry processing plants.
The main difference from dry processing would be that the dust control in
the plant would be easier, but the final tailings would be a water slurry
contaminated with asbestos-

Table 2-22 summarizes the waste characteristics from  the preliminary
screening study.  Asbestos containing materials are not currently listed as
hazardous by Subtitle C.  The EPA has proposed regulations  under  the Toxic
Substances Control Act that would regulate asbestos under 40 CFR  763
(Federal Register Vol. 51, number 19, Jan. 29, 1986).  Due  to  the hazardous
nature of asbestos, wastes containing the  fibers may  be regulated under
subtitle C in the future.

-------
                             Figure 2-42

                          ASBESTOS PROCESSING
         Rough Crude
                                  Ore
                                   1
                                 Size
                               Reduction
 Coarse
 Sorting
Sized Fiber Products*-
Multiple
 Stage
Screening
      Coarse Waste
•>(2) Fine Tailings
                                2-133

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                                          Table 2-22

                                        ASBESTOS UASTES

Process
Benef iciation




Waste
1) Coarse Waste Rock

2) Tailings

Possible RCRA Characteristic*
R C I T Comments
N N N N Asbestos
contamination
N N N N Asbestos
contamination
* RCRA characteristics are Reactivity, Corrosivity,  Ignitability and  EP Toxicity  as defined  in
    AOCFR 261 Subpart C.

N - Waste not expected to exhibit this characteristic.
Y - Strong indication that waste would exhibit this  characteristic.
? - Possibility that waste could exhibit this characteristic.

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                                   SHALE
Shale, for the purpose of this report, is a clay bearing rock that has been
indurated into flat plates.  It is used for its clay content and to make
lightweight aggregate.

When used as a clay source, shale is ground to release the clay and the
entire rock, is used.  It is used in low economic value, high volume
applications such as brick, sever tile, and vitrified pipe.  Because of the
low economic value the shales are used without any other processing than
size reduction and the process produces no waste (Table 2-23).

Shale is also used to make lightweight aggregate for use in concrete.  Vhen
heated to a suitable temperature, the shale expands or bloats and forms a
porous, competent, light weight aggregate.  This strong, light aggregate is
used to make light weight concrete.  Kiln dust is produced by the process,
which is the only waste.  This waste probably would not exhibit hazardous
characteristics by itself.  However, some operations are using listed
wastes, such as used solvents, for fuel in their kilns.  Current
regulations would consider the use of listed waste as a fuel  to be
processing of liquid waste and all wastes from processing of  liquid wastes
are also listed wastes by definition.  The kiln dusts could then be
considered hazardous since they are partially derived from  the processing
of listed wastes.

-------
N)
I
                                                        Table 2-23

                                                   SHALE PROCESSING WASTES
                                                           Possible RCRA Characteristic*
Process                 Waste                              R   C   I   T       Comments


Expansion               Kiln Dust                          N     N   N   N   Hay be derived
                                                                              from hazardous
                                                                              waste fuel


* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined
  in 40CFR 261 Subpart C.

N - Waste not expected to exhibit  this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility  that waste could exhibit this characteristic.

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                           3.0  METAL INDUSTRIES

INTRODUCTION

This chapter contains reports on 32 metal commodities produced in the U.S.
from mineral sources.  The quantities of metals produced by these
industries range from less than 200 pounds per year to more than 80 million
long tons per year.

Further study of the industries producing five metallic commodities is not
recommended.  These recommendations are based On low volume of production
or a recent total shutdown of all production facilities.  The 27 metal
industries that are recommended for further study may not all require
regulation under Subtitle C,  but the readily available literature did not
contain sufficient information on waste characteristics and disposal
practices to determine if such regulation was appropriate.
                                   3-1

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                                  ARSENIC

The most important sources of arsenic are byproduct materials from the
smelting of copper and lead concentrates.  Arsenic trioxide is volatilized
during smelting and is concentrated in the flue dust.   This flue dust can
be processed to produce arsenic trioxide as the final  product.  Arsenic
trioxide vas produced from flue dust in the United States until 1985.  At
that time, the last operation in Tacoma, Vashington closed.  Since then,
both arsenic metal and the trioxide have been imported.

It is estimated that over 92% of the arsenic imported  in 1986 vas in the
form of arsenic trioxide.  The majority of this arsenic is used in wood
preservatives and herbicides.  Metallic arsenic is used in nonferrous
alloys and as a material for semiconductors in the electronics industry.

The industrial process for production of arsenic trioxide involves roasting
flue dust with pyrite or galena to volatilize the arsenic.  The vapors are
sent to a series of brick cooling chambers called kitchens.  The majority
of the arsenic trioxide condenses to produce a product of 99-99.9% purity.
The arsenic trioxide condensing in the warmest or coolest kitchens is
generally less than 90% pure and is pressure leached and recrystallized  to
produce a more pure product.

At present, arsenic trioxide is not produced in the United States.  The
majority of the refineries have been closed permanently.  For these
reasons, further study of arsenic production for possible regulation under
RCRA subtitle C is not necessary.
                                   3-2

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                                REFERENCES

Grayson, Martin, exec, ed.; Encyclopedia of Chemical Technology, 3rd
     Edition; Viley-Interscience; New York., New York; 1978.

Liddell, Donald M., ed.; Handbook of Nonferrous Metallurgy; McGraw-Hill
     Book Co., Inc.; New York, New York; 1945.

U.S. Department of the Interior, Bureau of Mines; Mineral Commodity
     Summaries 1987; U.S. Bureau of Mines.
                                   3-3

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                                  COBALT
Cobalt and cobalt alloys have several major uses stemming from their
ability to maintain high strength and corrosion-resistant properties when
heated to high temperatures.  Cobalt's principal use is in superalloys used
in jet aircraft and industrial turbine engines.   In addition,  it  is used in
drying agents in paints, as a catalyst in petroleum refining,  and in
magnetic alloys.

The large majority of cobalt occurs in mineral forms as arsenides,
sulfides,  and oxides.  Predominant cobalt minerals include linnaeite
(Co-S,),  carrollite (CuCO^S,), safflorite (CoAs2), skutterudite
((Co,Fe)As_), erythsite (Co-CAsO^Sh^O), and glaucodot ((Co, Fe)AsS).

There has been no mining of cobalt in the United States since 1971 due to
unfavorable economics, and no mining is expected in the foreseeable future.
However,  there are an estimated 1.4 million tons of land-based cobalt
deposits in the United States.  Most deposits are in Minnesota and the
northwest states.

If domestic mining of cobalt resumed at a future date, the lateritic ores
found in Idaho and Missouri would be the choice ore for development.
Lateritic ore contains 0.06 to 0.25% cobalt.

The U.S.  Bureau of Mines has developed a process  for the recovery of cobalt
from lateritic ores.  This process is shown in Figure 3-1.  Dried ore  is
roasted at 525°C in a reducing atmosphere of carbon monoxide  for 15
minutes.   Cobalt (and nickel) is  then extracted from  the ore  into solution
during an ammoniacal leach.  The  spent ore  is thickened before being
discarded, resulting in a wastewater stream requiring proper  disposal
(Table 3-1).  The extraction solution is filtered,  producing  waste  solids,
and excess ammonia is removed by  steam heating.   Cobalt  is  then  removed
from the solution by organic stripping, and spent cobalt electrolyte  is
                                   3-4

-------
                               Figure 3-1

                  COBALT BENEFICIATION FROM LATERITIC ORE
                     LATERITIC ORE (0.06 to 0.25Z Co)
Carbon _
Monoxide
Ammonia
Solution
Steam
Organic
Stripper
Spent  	
Electrolyte
 High Temperature
Chemical Reaction
      -^Exhaust
                                   A.
   Ammoniacal
      Leach
Solids
                                   V
   -^Thickening )—>Vastevater
         i	> Slag
                                Filtering"!—:	» Waste Solids
                                       Filtrate
•* Steam Heating
     -> Steam & Ammonia
    Stripping  |	;	> Waste Stripper
   I  Wishing   j	
        ^
   Electrolysis |
                                                 -> Wash Waste
                          Metallic Cobalt Product
                                  3-5

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                                                   Table 3-1

                                         COBALT BENEFICIATION WASTES
Possible RCRA
Cliaracterist ics
Process
Ammoniacal Leach
Thickening
u» Filtering
3\
Stripping
Washing
Waste
1) Solids
1) Wastewater
2) Slag
1) Waste Solids
1) Waste Stripper
2) Washing Waste
R
N
N
N
N
N
N
C
7
N
N
N
7
7
I
N
N
N
N
N
N
T Comments
7
7
7
7
7
7
* RCRA characteristics are  reactivity, corrosivity, ignitability, and EP toxicity as defined  in  40  CFR  261
  Subpart C.

N - Waste not expected to exhibit  this characteristic.
Y - Strong indication that  waste would exhibit this characteristic.
? - Possibility that waste  could exhibit this characteristic.

-------
used to separate the cobalt from the stripping solution.   The stripping
solution is discarded as waste.  Electrolysis is used to precipitate the
metallic cobalt product.  The Bureau of Mines has reported cobalt
recoveries of 80 to 90% by this process.

Cobalt is often recovered during the mining and beneficiation of copper and
nickel-containing ores.  The AMAX Nickel Company, which had the only cobalt
refining capacity in the U.S. closed its plant at the Port Nickel,
Louisiana plant in 1985.  Imported copper-nickel cobalt mattes have been
used as the source of cobalt.  The cobalt was recovered by atmospheric
leaching and hydrogenation which precipitates cobalt from solution.  The
Port Nickel refinery is now reprocessing petroleum refining catalysts to
recover vanadium, molybdenum, and alumina.  There are no current plans  to
reopen the cobalt refinery, but it could be put back into production if the
economic conditions become favorable.

As previously mentioned, there is currently no mining in the United States.
If mining of the lateritic ore deposits becomes economically practical  at  a
later date, then investigation and characterization of the wastes produced
would be needed, since no full-scale operations exist today.  However,  no
development of domestic cobalt deposits is expected in the near  future.
Therefore, no further investigation of  the wastes for potential  regulations
under Subtitle C associated with the mining, beneficiation, or processing
of cobalt is recommended at  this time.
                                    3-7

-------
                                REFERENCES

Bureau of Mines, 1987.  Mineral Commodity Summaries, 1987.

Marks, H.F., ed.; Encyclopedia of Chemical Technology; Viley Intel-science,
     New York, New York, 1978.

Smith, Ivan C., et al.; Trace Metals in the Environment Volume 6-Cobalt;
     Ann Arbor Science Publishers, Inc.; Ann Arbor, Michigan; 1981.
                                   3-8

-------
                                  MERCURY

Mercury metal is a silver-white liquid at room temperature  and  a  colorless
vapor above its boiling point of 356.9°C.  Mercury is  an excellent
conductor of electricity,  is stable in oxygen, carbon  dioxide and air,
readily combines with halogens and sulfur,  and alloys  easily with other
metals forming amalgams.  Mercury exhibits  a high surface tension and a
uniform volume expansion vith respect  to temperature.

Mercury's electrical conductivity, uniform  expansion over a wide
temperature range, and toxicity render it  useful in several  industries.
Batteries comprise the largest use of  mercury.  Low pressure  mercury
(fluorescent) and high pressure mercury lamps are used widely  for household
and industrial lighting.  The uniform volume expansion and high surface
tension of mercury make it ideal for use in temperature and pressure
sensing devices such as thermometers and manometers.  In agriculture,
mercuric compounds are used primarily as bactericides  and disinfectants,
and as a pharmaceutical, mercury is 'used in diuretics, antiseptics, skin
preparations, and preservatives.  Mercury is also used as a catalyst in the
manufacture of anthraquinone derivatives, vinyl chloride momomers and
urethane polymers.

Mercury ore is found in over twelve sulfur combined minerals.   Cinnabar
(HgS) is the most common mercury mineral.  Other commercially significant
mercury minerals include corderite (Hg.S-Cl-), livingstonite (HgSb.S,),
montroydite (HgO), terlinguaite (Hg2OCl), calomel (HgCl), and metacinnabar
(black cinnabar).  Mercury deposits occur in  the continental rock
formations which are faulted or fractured and have an epithermal character,
such as limestone, calcareous shales,  sandstones, serpentine,  chert,
andestine, basalt, and rhyolite.  Deposits are found at  relatively shallow
depths (from 1 to 1,000 meters).  Ores  typically contain between 4  to  20  kg
of mercury per ton.
                                   3-9

-------
Mercury ore is mined using open pit and underground methods. .  Mercury mined
underground comprises 90£ of overall world production.   The open pit mine
at McDermit, Nevada, closed in January, 1987.  Until its closing,  the
McDermit mine vas the only active mine in the United States.   Other mines
in California may operate intermittently.  Mercury can also be extracted as
a secondary product in the refining of precious metals.

At the Nevada mine, beneficiation consisted of crushing followed by
separation in a flotation cell (Figure 3-2).  The flotation concentrate was
then heated in a furnace to reduce and vaporize the mercury.   The mercury
metal is recovered by condensation in a cooling system.  The recovered
mercury, known as prime virgin mercury, was 99'.9% pure and contained less
than 1 ppm base metal concentrations.  The wastewater produced in both the
flotation and cooling processes was impounded in multiple evaporation
ponds (Table 3-2).  There is no resulting discharge.  Other intermittent
operations in California and Nevada do not beneficiate the ore and
therefore water is only used for cooling.  Any cooling water discharges
would likely not be hazardous.

The past five years have seen a downward trend in the primary production of
mercury.  Mercury production is measured by  the flask (1 flask = 76
pounds).  In 1982, mine production of mercury was reported to be 25,760
flasks, compared to 16,530 flasks in 1985.  This downward trend in
production was caused by the availability of low-cost foreign material and
sales of government stockpiles.  Demand for mercury products such as
pesticides, fungicides, paints,and antiseptics had dropped due  to
replacement with other effective but less toxic substances.  The fact  that
mercury is not currently produced in the United States and the  zero
discharge operation suggest that the mercury production  industry need  not
be studied further for potential regulation  under Subtitle C of RCRA.
                                    3-10

-------
                            Figure 3-2

                             MERCURY
Cooling
 Water
                   Mercury Ore
                   Crushing
                r
                   Flotation
                                   Tailin'g Slurry
                                   Evaporation
                                      Pond
                          Flotation Concentrate
                   Furnace
                     or
                   Retort
            Air Emissions
                          Mercury
                           Vapor
Cooling
System
               Elemental Mercury
Wastewater
                                 3-11

-------
                                                          Table 3-2

                                                  MERCURY  PROCESSING  WASTES
                                                                        Possible  RCRA  Characteristics

                 Process                          Waste                   R     C     I    T  Comments


       Flotation                          1)  Flotation  Tailings          ?     ?     N    ?    May contain  toxic metals
                                                                                           or sulfides


       * RCRA characteristics  are  Reactivity,  Corrosivity,  Ignilability,  and EP  Toxicity as defined in  40 CFR 261
u>        Subpart C.
i-»
10      N - Waste not expected  to exhibit  this  characteristic.
       Y - Strong  indication  that  waste would  exhibit  this  characteristic.
       ? - Possibility  that waste  could exhibit  this characteristic.

-------
                               BIBLIOGRAPHY

Bureau of Mines, 1987.  Mineral Commodity Summaries, 1987.

EPA, 1982.  Development Document for Effluent Limitations Guidelines and
     Standards for the Ore Mining and Dressing Point Source Category,
     EPA-440/1-82/061.

Marks, 1978.  Encyclopedia of Chemical Technology, Mark, H.F., et al.,
     editors; Wiley Interscience, New York, New York, 1978.
                                   3-13

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                                  NICKEL
Nickel is a silvery-vhite, hard,  malleable,  ductile,  metal  widely  used  in
alloys to impart strength and corrosion resistance.   Many of  the  common
stainless steels contain nickel,  as do other corrosion resistant  alloys
such as Inconel, Monel, and the hastelloys.   It is also used  in high
strength steels such as tool and armor alloys.   Nickel plating is  used  as a
protective and decorative coating on other metals.  It has  also found use
in electronics, ceramics, magnets,  and in catalysts.

There is no primary producer of nickel in the United States,  although the
Hanna Mining Company, until recently, produced  ferro-nickel used  in
alloying steel at Riddle, Oregon, by smelting an ore containing nickel
oxide.  The ore is of a type called a "laterite" which is a weathered
deposit in which the nickel is concentrated in  soils by the chemical
breakdown of the original rock.  Fragments of the original  rock,  called
peridotite, remain in the deposit.   These fragments have low  nickel
contents and are much harder than the rest of the ore.  The processing, as
shown in the flow sheet in Figure 3-3, takes advantage of  that hardness to
upgrade the ore.

The first stage of processing is a screening step that removes ore
fragments that are coarser than 3" producing waste stream 1.   These large
pieces of rock are almost all peridotite and would not be expected  to
exhibit any hazardous characteristics.  Since the ore contains considerable
moisture it is next dried then screened again.   The drying tends  to break
down the softer parts of  the ore so  that removing particles coarser  than 1"
will remove peridotite producing waste stream 2 in Figure 3-3, which will
have the same characteristics as stream 1.

The dried material smaller than  1" is split into  coarse and fine  fractions
with the coarsest material being crushed to finer than 5/16".  The  coarse
and fine ore fractions are then  preheated in separate units.   The preheated
                                   3-U

-------
                                Figure 3-3

                           Nickel Ore  Processing
                           Hanna, Riddle, Oregon
 Nickel Metal 4.	
(small quantity)
Ferro Nickel Alloy^.
(primary product)
    Concentrates <—
    Recycled to
Melting or Refining
                                    Ore
                                   Size
                                Separation
                                   Dryer
                                   Size
                                Separation
   Melting
                                   _V
                                  Nickel
                                Reduction
                                    \/
                                  Nickel
                                 Refining
                                   _V
  Casting
Slag & Skull
 Treatment
                         Coarse Vaste
                      >(2)Coarse  Waste
                                                   (3)
                       Slag  to  granulation
                       and disposal
Tailings to Disposal
                                   3-15

-------
ore is then fed to electric melting furnaces.  The primary function of
these furnaces is to melt the ore for further processing,  but  a small
amount of metal is produced.

The molten ore is poured into one ladle of a "skip mixer"  which has two
ladles.  The other ladle contains previously made ferro nickel as "seed
metal".  The ladles are poured back and forth to provide mixing.
Ferro silicon is added as a solid reducing agent during the mixing.  After
seven pours the material is allowed to stand for a time to let the metal
and slag separate.  The slag is poured off and granulated  by high pressure
water jets prior to disposal.  The cooled slag would not be expected to
exhibit any hazardous characteristics.

The ferro-nickel alloy metal from the reduction step then  goes to a
refining step where phosphorous is removed.  The alloy is  cast into ingots
called "pigs" which are the final product of the process.   The slag from
refining, along with "skulls" (cooled material coatings) from the reaction
vessels and slag kettles and collected spillage are milled and treated by
magnetic separation to recover the metal values.  The metal concentrates
are recycled with fine concentrates returning to the melting stage and
coarse concentrates returning to the refining stage.  The tailings from
this treatment are discarded as waste 4 in Figure 3-3.  These tailings are
not expected to exhibit any hazardous characteristics (Table 3-3).

Low nickel prices caused the Hanna Mining Co. to suspend operations in May
of 1986, for an indefinite period.  The plant equipment has recently been
offered for sale by a used equipment dealer.

Two copper refineries produce nickel materials as by-products.   If nickel
is present in a copper ore, some will follow the copper through  the
preliminary stages of processing and nickel will be  found  in  the  impure
metal that is cast into anodes for electro-refining.  The nickel  will
dissolve and build up in the electrolyte solution as  copper dissolves.   The
nickel must be kept at a low concentration  to prevent contamination  of  the
                                   3-16

-------
refined copper.  A portion of the electrolyte from all of the cells in the
refinery is removed continuously as a bleed stream and is treated to remove
the nickel and other contaminants.   The purified stream is returned to the
refining cells, which dilutes the contaminants present, keeping their
concentrations low enough to prevent interference with the copper refining.

The treatment of the bleed stream is a three-step process.  In the first
step, part of the copper is plated out of the solution under conditions
that give a high purity product essentially the same as the primary
refining process.  In the second step, the rest of the copper is plated out
of the bleed stream along with any arsenic, antimony, and bismuth.  The
metal from this step is purified to remove the'contaminants and returned to
the main refining process.  The remaining bleed stream solution is then
treated by evaporation of the water, which causes the nickel, and any
remaining copper, arsenic, antimony, bismuth, iron, and cobalt to
precipitate as sulfate.  The nickel sulfate is purified and sold for
electroplating and other chemical uses.  Most of the acid remaining after
the precipitation step is returned to the main refining process.  A portion
is neutralized and discarded to prevent buildup of calcium, magnesium,
potassium, and sodium ions in the electrolyte solution.  This sludge and
the remnants of the nickel suifate purification could exhibit hazardous
characteristics due primarily to leachable metals.

Nickel production in the United States is limit.ed to two producers of
nickel materials as a by-product of copper refining.  There are wastes  from
nickel production as a by-product of copper production that could exhibit
hazardous characteristics but it appears logical to address  those wastes  in
the context of copper production.  Therefore, no further  study of  the
nickel production industry for possible regulation under  RCRA  Subtitle  C  is
recommended.
                                   3-17

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                                                          Table 3-3

                                                   NICKEL PROCESSING WASTES
                 Process
                                         Waste
                              Possible RCRA  Characteristics*
                              R    C    I     T      Comments
OJ
i—•
co
Laterite Smelting
  First Size Separation
  Second Size Separation
  Reduction
  Skull & Slag Processing

Copper Refining
  Nickel Purification
  Acid Bled Neutralization
                                          1) Coarse  peridotite
                                          2) Finer peridotite
                                          3) Reduction  Slag
                                          4) Tailings
1) Residue
2) Sludge
                              N
                              N
                              N
                              N
N
N
     N
     N
     N
     N
?
N
     N
     N
     N
     N
N
N
     N
     N
     N
     N
       * RCRA characteristics are Reactivity, Corrosivity, Ignitability, and EP Toxicity as defined in 40 CFR 261
         Subpart C.                                                             -

       N - Waste not expected to exhibit  this characteristic.
       Y - Strong  indication that waste would exhibit  this characteristic.
       ? - Possibility  that waste could exhibit  this characteristic.

-------
                                REFERENCES


Boldt, Queneau, The Winning of Nickel, 1967.  International Nickel Company
     of Canada Ltd.  Published by 0. Van Nostrand.

Biswass and Davenport, Extractive Metallurgy of Copper, 1976, Pergamon
     Press.

U.S. Bureau of Mines, Mineral Commodity Summaries, 1987.

U.S. Bureau of Mines, Minerals Yearbook, 1985, Volume 1.

U.S. Bureau of Mines, Mineral Facts and Problems, 1985.
                                     3-19

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                                 SCANDIUM

Scandium is a soft silver metal which has a slight yellov cast when exposed
to air.  Scandium readily reacts with acids and is not easily attacked by
water.  The metal does not tarnish in air,  but at high temperatures (500°
to 800°C) scandium can be oxidized in air.   Scandium is extremely
electropositive, and, therefore, its oxide is basic and acid soluble.
Scandium exhibits a trivalent state in compounds and has no other observed
valences.  Scandium is chemically similar to rare earth elements; however,
its ion size places it in geochemical equilibria with aluminum, magnesium,
hafnium, and zirconium.  Therefore, scandium is rarely found in rare earth
ores, but has been noted in minor amounts in gadolinite, xenotime,
allanite, davidite and others.

Scandium occurs an estimated 7 ppm in the earth's crust, and at about
0.... .004 ppm in sea water.  One of the scandium-rich ore minerals is
thortveitite, (ScY^.SijO,, which contains 33 to 42 percent scandium oxide.
Thortveitite is found as greyish green, translucent to transparent,
prismatic crystals often found in pegmatites.  In igneous rocks scandium  is
concentrated in pyroxenes, amphiboles and biotite with contents up to 0.5
percent scandium oxide.  Pegmatite formations are estimated to contain 5  to
20 ppm of scandium.  Scandium also occurs in low concentrations in
wolframite, euxenite, cassiterite, and some uranium deposits.

There are very few commercial uses for scandium.  Demand for scandium is
extremely low, causing market prices to be unpredictable.   Scandium is
principally sold in its oxide form, and in 1985  the total consumption was
estimated at 50 kilograms.

Currently, the principal uses for scandium are  in high-intensity mercury
vapor lamps and lasers.  Little is known about  scandium, and  laboratory
research is continuing.
                                   3-20

-------
In the United States, scandium was recovered in 1985  as  a  byproduct  from
thoriveitite-bearing fluorite screenings previously mined  at  Crystal
Mountain, Montana, uranium extracted from copper tailings  at  the  Bingham
Canyon copper mine in Utah, and from by-product tungsten concentrate from
molybdenum ores mined at Climax,  Colorado.

Scandium is extracted from thortveitite by several methods.   One  method
involves dissolution of thortveitite vith concentrated hydrochloric  or
sulfuric acid, yielding a gelatinous residue of scandium-containing  silica
(Figure 3-4).  Another method begins by finely grinding thortveitite vith
charcoal at 1,800°C, forming scandium carbide (Figure 3-5).   This carbide
is then further decomposed with hydrochloric a'cid forming soluble scandium
chloride.  The third method involves chlorinating thortveitite in the
presence of chlorine gas and carbon at 850°C to form scandium chloride
(Figure 3-6).  The scandium chloride is leached with sulfuric acid.   From
the residue of any of the three methods, scandium is recovered by adding
ammonium oxalate or tartrate to the solution, forming a scandium
precipitate.  This precipitate is filtered and washed, then decomposed by
ignition at 900°C.  An impure scandium oxide is formed and dissolved in
hydrochloric acid.  Scandium can also be extracted from thortveitite using
hydrofluoric acid in a similar method.  Methods using magnesium or
ammonium-hydrogen fluoride have been used.  Ion exchange or solvent
extraction is used for further purification.

Scandium has been found to closely  follow uranium in solvent extraction
operations (Figure 3-7).  By using  dodecyl phosphoric acid in kerosene,
scandium does not strip with uranium, but remains in  the solvent.  The  ore
is crushed and ground, then leached with dilute sulfuric acid.  Oxidant  was
added to convert uranium metals to  soluble  form for solvent extraction.
Stripped solvent, from the solvent  extraction  process, contains less  than
0.1 ppm scandium.  This solution  is fed  through a  two-stage countercurrent
solvent extraction system and  is  treated with  hydrofluoric acid.  The
stream is filtered  to yield a  cake  that  is  10  percent scandium oxide
      ) and 20 percent thorium oxide  (ThO-).   This cake is digested  in  a

                                    3-21

-------
thortveitite ore
sulfuric acid
Ammonium  Oxalate
or Tartrate
                                 Figure 3-4

                       SCANDIUM FROM THORTVEITITE 11
                         Concentrated hydrochloric
                             or sulfuric acid
Dissolution
                                    V
                              silica residue
                            containing scandium
                                    i
X

leaching
process
\
t
                             leaching solution
N,

N
/
Precipitation
                           Scandium precipitate
                                    _V
                            I      Filter
                                    _V
                                   Wash
\
/
Ignition 900°C j
'spent  acid
                   •waste sulfuric acid
                    waste solution
                       :nt wash water
                                     3-22

-------
                                Figure 3-5

                                 SCANDIUM
                              THORTVEITITE 12
thortveitite ore-
hydrochloric acid-
sulfuric acid-
Ammonium Oxalate
or Tartrate
                                  Charcoal
  grinding
   1800°C
                                    V
                             scandium carbide
  leaching
                                    V
                             scandium chloride
                                   1
  Leaching
                             leaching solution
Precipitation
                           Scandium precipitate
                                  Filter
                                   Vash
                              Ignition 900°C
•vaste acid
•waste sulfuric acid
•vaste solution
                                      3-23

-------
Thortveitite ore
Sulfuric acid-
Ammonium Oxalate
or Tartrate
                                Figure 3-6

                                 SCANDIUM
                              THORTVEITITE 13
Chlorination
    850°
                             Scandium Chloride
                                   1
   Leaching
                                   T
                             leaching solution

                                   i
•^
s1
Precipitation
\
/
                           Scandium precipitate
                                   1
                                  Filter
                                   Vash
                              Ignition 9008C
                                    V
                              Scandium oxide
Vaste   chlorine
solution
>Vaste sulfuric acid
                     waste solution
                     filter vash
                                      3-24

-------
Fuel-
              Figure 3-10

           ANTIMONY SMELTING
 Blast
Furnace
                                  Medium Grade
                                  Antimony Oi:e
Slajr
Waste or
Reprocessing
            Antimony Metal
             3-35

-------
LIQUATION

As shovn in Figure 3-11, during liquation high grade  ores  are  he?.:ed in
either a perforated pot (batch mode) or reverberatory furnace  (continuous
mode) which allows separation of the melted rich sulfide ore from  the slag
or residue.  It is important to provide a reducing atmosphere  to prevent
oxidation or volatilization losses.  The residue,  which generally  contains
12-30X antimony is reprocessed by oxide volatilization to  recover  the
antimony.  The rich sulfide ore is known as needle antimony, and elemental
antimony can be produced using the iron precipitation process,  or  by
conversion to the oxide, with subsequent volatilization and oxide
reduction.

IRON PRECIPITATION

The iron precipitation process for conversion of antimony sulfide to
elemental antimony is suitable for both high grade ores and needle
antimony.  As shown in Figure 3-12, the ore is heated with excess iron
scrap that serves as a reductant for the antimony.  Carbon and sodium
sulfate are added to produce excess sulfide to promote iron sulfide
production, and salt is added to facilitate formation of an iron sulfide
matte that can be skimmed off the molten metal.  Because the antimony
produced contains unacceptably high concentrations of iron and sulfur, a
secondary fusion process is used where needle antimony and salt are heated
with the antimony to produce more iron matte and purified antimony metal.
The iron matte is either reprocessed by blast furnace smelting, or becomes
a waste stream, which might exhibit the RCRA characteristics of reactivity,
or EP toxicity.

OXIDE REDUCTION

Antimony trioxide from  the oxide volatilization process is  reduced  to
antimony in a reverberatory furnace.  As shown  in  Figure 3-13,  charcoal  is
added to serve as a reductant, and  flux agents  (soda,  potash,  sodium
sulfate) are added to dissolve sulfides and minimize  volatilization.
                                   3-36

-------
       Figure 3-11

  ANTIMONY PROCESSING
   LIQUATION PROCESS
               Antimony Ore (40-60X sb )
      Perforated
          Pot
           or
     Reverberatory
        Furnace
      (550-600°C)
 Needle
Antimony
               Gangue
             (12-30* Sb)
To Oxide Volatilization
      (Figure 1)
        \l
             -"•• Product
                                 Metal
                               Reduction
                                    \f
                                Antimony Metal
         3-37

-------
                       Figure 3-12

                        ANTIMONY
                   IRON PRECIPITATION
                    REDUCTION PROCESS
    Iron Scrap-
Carbon + Na.SO,-
         Saft —
   Needle
  Antimony•
     Salt-
                                           High  Grade  Antimony Ore
                                                (40-602)
                                                   or
                                           Needle  Antimony
Fusion
  \>
                                   Iron Sulfide
                                       Matte
                             Antimony Metal
Secondary
 Fusion
           Iron Sulfide
               Matte
                             Purified
                          Antimony Metal
                              Waste or
                            Blast Furnace
                              Smelting
                           3-38

-------
Charcoal-
Soda, 	
Potash,  or
Sodium Sulfate
                                Figure 3-13

                                 ANTIMONY
                          OXIDE REDUCTION PROCESS
                                             Antimony
                                              Oxide
Reverberatory
   Furnace
                               Slag
                                Antimony Metal
                                                        Sb.O.  (particulate)
Com-ell ppt
     01:
   Daghouse
                                   3-39

-------
Nevertheless, volatilization of antimony is significant  requiring a
Cottrell precipitator or baghouse to recover the antimony  trioxide for
reprocessing.  The main waste stream is the slag formed,  but,  baghouse dust
would be a waste if not directly recycled into the process.

LEACHING AND ELECTROLYSIS

The ASARCO plant in El Paso, Texas,  and the Sunshine Mining Co.,  Sunshine,
Idaho, each utilize a leaching-electrowinning process for  recovery of
antimony from complex ores.  As shown in Figure 3-14, the  ores are first
leached with alkali hydroxide or sulfide for extraction  of the antimony in
the form of sodium thioantimonate (Na,,SbS,).  The sodium thioantimonate is
reduced by electrolysis at an iron or mild steel cathode in a diaphragm
cell.  The leachate remaining after electrolysis is a waste stream
generated from this process.  The composition of this stream is not
detailed in the literature and needs further characterization.

REFINING

Pyrometallurgically produced antimony metal requires further refining to
remove arsenic, sulfur, iron, and copper impurities.  As shown in Figure
3-15, this is accomplished by heating the antimony with  sodium sulfate,
charcoal, and stibnite to form an iron matte which is skimmed from the
surface.  Arsenic and sulfur are removed by heating in an oxidizing
environment created by the addition of caustic soda, sodium carbonate, and
niter (sodium nitrate).  It is assumed that this process necessarily
generates an arsenic sulfur waste.  Lead is not readily removed.  However,
if lead was present in the antimony metal undergoing refining, the product
is usable for lead base alloy applications.  Lead and other,  impurities can
be partially removed by electrolytic refining.
                                   3-40

-------
                               Figure  3-14

                            ANTIMONY REDUCTION
                                    BY
                         LEACHING AND ELECTROLYSIS
Alkali  .
Hydroxide
  or
Sulfide
                                       Complex
                                         Ores
Leaching
Electrolyte
  Further
Processing?
                                          Leachate Containing
                              Elcctirovinning
                Electrolyte
    Waste
                               Antimony Metal
                                   3-41

-------
NaOH
NaNO.
                      Figure  3-15

                   ANTIMONY REFINING
                            Antimony Metnl  From
                            Pyrometallurgic Process
Or „, ._r 'r-
Stibnite
A

^s

Fluxing
Iron
Matte

Waste or
Further
Processing


Oxidize
Fluxing


                    Antimony Metal

                     185-95% Sb)
                                             Uaste Concaininc
                                                As & S
                           3-A2

-------
CONCLUSION

Gangue and slag are the major wastes produced in the initial processing of
various grade antimony ores (Table 3-5).  The quantities produced,  their
chemical characteristics, and their disposition are not available in the
literature.  The antimony reduction and refining processes produce iron
matte, slag, and the sulfur/arsenic waste from oxidizing fluxing.  Again
the quantities, characteristics, and disposition of these wastes are not
available in literature.  Although the leaching electrolysis process has
current limited use, residue arid leachate are produced that may have
hazardous characteristics.  It is recommended that the antimony production
industry be further investigated for possible regulation under Subtitle C
of RCRA.
                                   3-43

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                                                          Table 3-5
                                                ANTIMONY PROCESSING WASTES
             Process
                                      Waste
Possible RCRA Characteristics
R    C    I    T     Comments
OJ
\
Oxide Volatilization
Smelting
Iron Precipitation and Reduction
Oxide Reduction
Antimony Reduction by
Leach ing/ Electro lysis
Antimony Refining
Scrubber Sludge
Gangue
Bag House Dust
Slag
Iron Sulfide Matte
Slag, Bag House Dust
Leaching Residue
Waste Leachate
Iron Matte
Oxidized Fluxing Waste
N
N
N
N
7
N
N
N
N
N
N
N
N
N
N
7
7
7
N
7
N
N
N
N
N
N
7
7
N
N
N
7
? May be recycled
7
7
? Baghouse dust may be
recycled
7
7
7
7
      * RCRA characteristics are Reactivity, Corrosivity, Ignitability, and EP Toxicity as defined in 40 CFR  261
        Subpart C.
      N
      Y
Waste not expected to exhibit  this characteristic.
Strong indication that waste would exhibit this characteristic.
Possibility that waste could exhibit  this characteristic.

-------
                                REFERENCES

Bureau of Mines, 1987.  Mineral Commodities Summary,  1987.

Marks, 1978.  Encyclopedia of Chemical Technology,  Marks, H.F., et al.,
     editors;  Wiley Interscience,  New York, New York, 1978.
                                   3-45

-------
                                 BERYLLIUM

Beryllium (Be) occurs in a number of minerals,  including  beryl
(3 BeO.Al-O-.e SiO~), bertrandite [Be^SijC^ (OH)2J,  and chrysoberyl
(Al_BeO,).  The major deposits of beryllium containing materials  in  the
United States are bertrandite deposits in the Spor Mountains of Utah,
spodumene pegmatite in the Carolinas, and chrysoberyl in  the strongly
faulted areas of the Seward Peninsula in Alaska.   The bertrandite deposit
in Utah is the only area that is actively mined.   Estimated production for
1986 was 261 short tons of contained beryllium.  Beryl is imported,  mainly
from Brazil and China, to be processed in the United States.  Approximately
60 short tons (contained beryllium) of beryl were imported in 1986.

Beryllium is a light weight, high strength metal with a high thermal
conductivity.  It also has a low neutron-capture cross section and a high
neutron scattering cross section.  These properties make  the metal useful
for application in the nuclear weapons, defense,  and aerospace industries.
It is used as the metal, as a beryllium-copper alloy, and as beryllium
oxide (for ceramic applications).

The Spor Mountain bertrandite deposit is currently being  mined by only one
company (Brush Villman).  A Joint venture was recently announced to open a
bertrandite mining operation adjacent to the current Spor Mountain
operation in Utah.  A joint venture between Cabot Corp.  and Cyprus Minerals
Co. was announced in October, 1986  to develop Cabot's property, Sierra
Blanca, near El Paso, Texas.  The deposit reportedly contains bertrandite
and behoite  (BeOI^).  Cyprus planned  to complete  feasibility studies and
mine development within two years.

Processing of bertrandite and imported beryl takes place  in  the same plant
in Delta, Utah.  Both processes  attempt  to extract the beryllium  from  the
respective ores as a solution of beryllium sulfate.  Once  in solution,  the
two pregnant liquors cannot only be  combined but  tend to  have a synergistic
                                   3-46

-------
impact because of differences in concentration and chemical composition.
Once combined, the ore source from which the beryllium was derived loses
identity and the combined leach liquor continues through the balance of the
process to final product.  Thus, the significant differences in the two
processes are involved in the procedures required to solubilize the
beryllium values from the respective ores.

The bertrandite ore is crushed, wet milled, and sized.  The contained
beryllium can then be leached or placed in solution under moderate
conditions of temperature (95°C) and acid concentration.  In contrast, the
beryllium values in beryl are tightly bound in the crystal structure of the
mineral.  To effectively attack the mineral with acid, it is first
necessary to destroy the crystal structure.  In the Delta process the ore
is melted at 1700°C and quenched rapidly in water to fracture and freeze
the particles (frit) formed as a solid solution.  The frit is heat treated
at about 1000°C, ball milled to 325 mesh, reacted with concentrated
•sulfuric acid at 325°C before the beryllium values can finally be
solubilized.  This is done by slurrying the sulfated frit in water.  The
leached or spent solids in both processes are separated from the beryllium
sulfate leach liquor using thickeners and washing the solids by counter
current decantation (CCD) before discarding the solids to the waste
(tailings)pond.  Once again, the differences required for processing  the
two ores are emphasized by the size of the thickeners involved.  The  beryl
system uses five 15-foot diameter thickeners while the bertrandite process
requires eight 90-foot diameter units.  The leach liquor  from  the  two
processes can be combined at this point and proceed through  the balance of
the process to the final product.  In the leaching operations, elements
other  than beryllium are also solubilized and must be removed  in  process  to
prevent product contamination.  The solvent extraction  system  rejects all
elements adequately requiring no subsequent treatment except for  uranium,
iron,  aluminum, and fluoride.  The solvent extraction process  at  Delta uses
an organic that has good selectivity  for the extraction of  beryllium.  By
mixing the beryllium containing leach solution  vigorously with  the  organic,
some of the beryllium reacts with the organic.   By repeating this  process a
                                    3-47

-------
number of time in a counter current flow pattern of the aqueous and
organic, essentially all of the beryllium can be extracted into the organic
phase.  A multi-stage mixer settler system is incorporated at the Delta
Mill  to facilitate this operation.

The most concentrated organic relative to beryllium in the system is
referred to as loaded organic.  By contacting this stream vith ammonium
carbonate solution in a two stage mixer-settler system, the extraction
process is reversed,  stripping the beryllium from the organic into the
aqueous stream.  The stripped organic is converted to the acid form by
contacting it with sulfuric acid in a two stage mixer-settler system.  The
converted organic can then by recycled to the extraction train to repeat
the cycle.

The beryllium containing strip solution is then further treated for  the
removal of iron and aluminum in preparation for final hydrolysis.

After stripping, the beryllium is present as a solution of ammonium
beryllium carbonate.   Heating this solution to 91°C liberates part of  the
ammonia and carbon dioxide and results in the precipitation of beryllium
carbonate.  This is separated on a rotary vacuum drum filter and may be
drummed as a final product or be reslurried in deionized water and
processed to beryllium hydroxide.  This is accomplished by raising the
temperature to 160°C in a pressure vessel and filtering a second time.
Both products are packed and stored for future shipment.

The barren filtrate from the first filtration contains  the uranium values.
This stream is transferred to solar ponds for storage and subsequent
processing for uranium recovery.

A flov diagram of the beryl and bertrandite processes  is  presented  in
Figure 3-16.
                                   3-48

-------
                        Figure 3-16
BERYL ORE INPUT

     , r (NO CONTAINED IT)
                                     BERTRANOITE ORE IMPUT
                                     CRUSHING « WET GRINDING
                                      TO URANIUM EXTRA.CTION
                BERYLLIUM EXTRACTION PROCESSES
                                AT
                         BRUSH WELLMAN
                        DELTA, UTAH PLANT
                                   3-49

-------
Although the beryllium mining and milling industry is small,  the wastes
produced are potentially toxic (Table 3-6) and the vaste management methods
are not detailed in the literature.  It is therefore recommended that
further study be  undertaken to determine if the vastes generated by this
industry should be potentially regulated under Subtitle C of  RCRA.
                                   3-50

-------
                                                         Table 3-6

                                                      BERYLLIUM WASTES
u>
i
      Process
Waste
Possible RCRA Characteristic*
R    C    I    T    Comments
Dissolution
Solvent Extraction

Iron Hydrolysis
Product Filtration
Sludge
Raffinate
Spent Solvent
Sludge
Barren Filtrate
N
N
N
N
N
7
7
7
7
7
N
N
N
N
N
7
7
7
7
7
      * RCRA characteristics are Reactivity, Corrosivity, Ignitability, and EP Toxicity as defined in 40 CFR 261
          Subpart C.

      N - Waste not expected to exhibit  this characteristic.
      Y - Strong indication that waste would exhibit  this characteristic.
      ? - Possibility that waste could exhibit  this characteristic.

-------
                                REFERENCES

Grayson, Martin, exec, ed.; Encyclopedia o£ Chemical Technology.  3rd
     Edition; Wiley-Interscience; New York, New York; 1978.

Hausner, Henry H., ed.; Beryllium:  Its Metallurgy and Properties;
     University of California Press; Berkeley,  California;  1965.

Liddell, Donald M., ed.; Handbook of Nonferrous Metallurgy; McGraw-Hill
     Book Co., Inc.; New York, New York; 1945.

U.S. Department of Interior, Bureau of Mines; Mineral Commodity Summaries
     1987; U.S. Bureau of Mines; Washington,  D.C.; 1987.
                                   3-52

-------
                                  BISMUTH

Bismuth is a brittle, crystalline,  lustrous metal vith a pink color.
Bismuth exhibits a greater electrical resistance in solid state than  in the
liquid state.  The metal will oxidize only slightly in air,  but when  heated
above melting point, an oxide film is formed.   Bismuth is the most
diamagnetic of the metals; its thermal conductivity decreases in a magnetic
field.  It is readily reactive with halogens and sulfur; it  is not readily
attacked by hydrochloric acid, but is converted to bismuth sulfate by hot
sulfuric acid.

Bismuth occurs at an estimated 0.0043 to 1 gram/ton in the earth's crust.
The most abundant bismuth-containing minerals are bismite anoxide,
bismuthinite, a sulfide; and bismutite,  a hydrated carbonate.  Bismuth is a
chalophilic element, having been concentrated in the later magmatic stages
of crystallization or through deposition from hydrothermal solutions.
Bismuth is produced as a byproduct from the treatment •„. lead, copper, and
other metal ores.  Domestic sources of bismuth are concentrated in the
western United States in lead and lead-zinc ores.

In 1986, 50 percent of the bismuth used was consumed by the pharmaceutical
and chemical industry (U.S. Bureau of Mines, 1987).  The primary metal
industries consumed 25 percent and 23 percent of the bismuth consumption
was used to manufacture machine parts.  A thin film of bismuth has been
patented for microfilming information supplied by a pulsed laser.  It  is
also used as a window material for neutron transparency in medical
irradiation devices and in wire form for Hall effect (an electromagnetic
effect from current in a piece of metal aligned  in a magnetic  field  used  in
special motors or sensors) and thermoelectric applications.  Due  to  its  low
absorption cross-section for  thermal neutrons, bismuth has been used  in
                                         235   233
liquid-metal fission reactors as a fuel (   U,    U) carrier or isolant.
Bismuth is used to alloy vith other metals for solders, for molding
plastics as a heat transfer medium, and other metallurgical uses.
                                   3-53

-------
Domestic bismuth can be extracted as a byproduct  from copper and  tin ores,
but is most commonly associated with lead and lead-zinc  ores.

In the recovery of bismuth from copper ores,  the  bismuth will follow the
copper into the matte as shown in Figure 3-17.   When the matte is converted
to blister copper, the bismuth fumes off, and the fumes, along with other
elements, are caught in the baghouse.  The collected dusts are sent to a
lead-smelting process.  Bismuth remaining in  the  blister copper is
recovered from electrolytic slimes when the copper is refined.  The slimes
are handled so that the bismuth is collected  in lead bullion.  Recovery of
bismuth from lead or lead-zinc operations involves one of two processes:
Betterton-Kroll Process or Betts Electrolytic Process.

The Betterton-Kroll process used to produce the great majority of bismuth,
both domestically and throughout the world, (Figure 3-18) involves  the
addition of metallic calcium and magnesium to lead bullion in a melt; this
creates an inter-metallic compound that melts at  a higher temperature than
lead, but has a lower density.  The melt is cooled to just above  the
melting point of lead and the inter-metallic compound, high in bismuth
content, will solidify and float to the top to be skimmed off as a  dross.
This dross contains bismuth, calcium, magnesium,  and lead.  To remove the
residual lead, the dross is reheated, to melt the lead which pools  beneath
the dross float.  The lead-free dross is treated with chlorine and/or lead-
chloride to remove magnesium and calcium.  The result is a bismuth-lead
alloy, high in bismuth concentration.

Bismuth-lead alloy created by the Betterton-Kroll process is  treated  with
molten caustic soda to remove acidic elements such as arsenic  and  tellurium
and impurities as shown in Figure 3-19.  Then, the mix  is desilvered  by  the
Parkes desilverization process.  The resultant alloy  is  then  treated  with
chlorine gas at 500°C to remove zinc and lead (zinc and  lead  form chlorides
faster than bismuth).  The chlorination process will  continue  until the
desired amount of lead has been removed.  The bismuth is  oxidized with  air
and caustic soda and  the final refined product is 99.999  percent  pure.
                                   3-54

-------
                                  Figure 3-17

                                  DisMurn
                              COPPER SOURCES
Blister Copper-*-
Fire Refining
Electrolytic Refining
Pure Copper
                               Copper Matte
Converters
Anode Slimes
                         Slimes Processing
                                Lead Bullions-
                                  Bismuth
                                Extraction
•*• Flue Dusts
        1
   (Containing  Bismuth)
                                                    Lead Smelting
                                                                 Baqhousc Dust
                                      3-55

-------
                                 Figure 3-18

                                  BISMUTH
                          BETTERTON-KROLL PROCESS
                             Metallic Calcium
                               and Magnesium
Molten lead bullion
                              Kolten Compound
                              Cooling Process
 •lead  bullion
                                  Dross
                                Containing
              Intermetallic Bismuth, calcium, magnesium and Lead
                                   Heat
  residual  lead
                              lead-free dross
Chlorine
•S

Chlorination
\
/
*^
**
> magnesium and
  calcium chlorides
                            Bismuth-lead alloy

                                     1
                                 Refining
                                    T
                               Bismuth  metal
                                    3-56

-------
Bismuth-lead alloy
 Zinc
Chlorine gas
air caustic soda
                                 Figure 3-19

                                  BISMUTH
                                 REFINING
                               Caustic Soda
         Mixer
->Spent soda solution
                            Purified metal mix
Parkes Disilverization
        500°C
                              impure bismuth
      Oxidac j.on
                               Bismuth metal
                               99.999X pure
                                                    Silver, gold, zinc to
                                                         processing
->lead and  zinc  chlorides
                                                    excess chlorine
   Alloy  residue  spent
   Caustic  soda solution
                                      3-57

-------
The Betts electrolytic process (Figure 3-20) begins with a lead bullion,  90
percent lead, with impurities such as silver, gold, tin, bismuth,  copper,
etc.  The lead bullion is cast into anodes and set in parallel in  an
electrolytic cell.  Thin sheets of pure lead are hung from conductor bars
as cathodes.  Then several cells are connected electrically in series.   The
electrolyte solution is a mix of lead fluosilicate and fluosilic acid with
glue.  A direct current is run through the cells.  The lead from the anodes
is dissolved and deposited on the cathodes, the impurities are left as a
slime on the anodes.  The cathodes are removed, washed,  dried, and melted
to produce slag and metal.  The slimes are also washed,  dried, and melted.
The metal formed is melted and treated by selective oxidation to remove
arsenic, antimony, and some lead.  The metal is then sent to a cupel
furnace to form silver and gold done by further oxidation.  The cupel
slags, rich in bismuth, are crushed, mixed with sulfur,  and reduced with
carbon to a copper matte and impure bismuth metal.  This impure bismuth  is
refined in the same way as that from the Betterton-Kroll process.

Extraction of bismuth from roasted tin concentrates and other bismuth
containing material is accomplished by leaching with hydrochloric acid as
shown in Figure 3-21.  The acid leach liquor is clarified, diluted with
large volumes of water, and bismuth is precipitated as bismuth oxychloride.
For purity, the bismuth oxychloride is redissolved in hydrochloric acid  and
reprecipitated.  Wet bismuth .oxychloride can be reduced after drying and
mixing with soda ash and carbon, or by way of  iron and zinc in the presence
of hydrochloric acid.

Since bismuth is produced as a byproduct of copper,  tin, and  lead-zinc
ores, mining wastes are not of consequence here.   However, in  the
extraction methods, electrolysis and leaching, strong acids,  and sodas are
used which could result in waste caustic sodas, electrolytic  slimes, and
waste acids (Table 3-7).  Therefore, further investigation for possible
regulation under Subtitle C is recommended.
                                   3-58

-------
 Lead  Product
                                 Figure 3-20

                                   BISMUTH
                        BETTS ELECTROLYTIC EXTRACTION
                              90% Lead  Bullion
                                    Anode
                                   Casting
Electrolytic
  Refining
                                   Anode
                                  Slimes
                                                  _^ Spent Electrolyte
Arsenic, Antimony
Lead to Refining
Gold, Salver
to Refining
                                  Slimes
                                  Melting
  Selective
  Oxidation
 Cupelation
                                 Crushing
                                  Sulfur
                                  Hixing
                                     I
                                     3-59

-------
                          Figure  3-20 (continued)
Bismuth to Refining-<-
  Carbon
Reduction
->Slag
                               Copper Matte
                              To Cu processing
                                      3-60

-------
                                 Figure 3-21

                                  BISMUTH
                         BISMUTH-BEARING HETEIUALS
Bismuth-bearing
materials
water
hydrochloric acid-
Carbon
                             hydrochloric acid
•V

Leaching Process
\
f
                    •spent material
                               leach liquid
                                 Clarifior
  Dilution
                                                    waste water
                         Bismuth oxychloride (ppt)
Purification
                                                  -^waste acid solution

                                                      Fe( Zn, UC1
                            Bismuth Oxychloride
                                           (wet)
                                      y
                                                      oxychloride
                                                       process
                                 Reduction
                              with carbon
                     waste acid solution
                               Bismuth metal


                                      3-61

-------
                                                                 3-7


                                                        BISMUTH WASTES
u>
I

Process
From Copper
Betts Electrolytic
Process




Betterton-Kroll
Process



Leaching from Bismuth-
bearing Materials





* RCRA characteristics are
Subpart C.
N - Waste not expected to
Y - Strong indication that
? - Possibility that waste

Waste
—
Possible
R C

1) Spent Electrolytic Solution N

2) Spent Cupel Slag
3) Spent Soda Solution
4) Alloy Residue
5) Caustic Soda Solution
1) Magnesium and Calcium
Chlorides
2) Spent Soda Solutions
3) Alloy Residue
4) Caustic Soda Solution
1) Spent Materials

2) Wastewater (dilution)
3) Waste Acid Solution
(puri f ication)
4) Waste Acid Solution
(reduction)
Reactivity, Corrosivity, Ignitabili

exhibit this characteristic.

N N
N ?
N N
N ?
N N

N ?
N N
N ?
N N

N ?

N ?
N ?

ty, and EP


RCRA
I

7

N
N
N
N
N

N
N
N
N

N

N
N

Characteristic*
T Comments

N ?

7
7
7
7
N

7
7
•'
t

7

?
7

Toxicity as defined in 40 CFR 261




waste would exhibit this characteristic.
could exhibit this characteristic.




-------
                                REFERENCES




Bureau of Mines, Mineral Commodities Summary, 1987.




Marks, H.U., Encyclopedia of Chemical Technology,  1978.
                                   3-63

-------
                                  CADMIUM

Cadmium is a soft, ductile, silver-white metal,  originally  discovered  as an
impurity in zinc carbonate.  Cadmium usually occurs in its  +2  oxidation
state in compounds and there are eight natural isotopes.  The  metal readily
reacts with halogens, phosphorous, selenium, sulfur,  and  tellurium when
heated.  Cadmium is resistant to alkali and salt water,  is  ductile, and has
good solderability.

Cadmium is primarily used as an electroplated coating on  steel and cast
iron parts for corrosion resistance.  The metal exhibits  an ability to
deposit uniformly on intricate objects.  Cadmium plate is generally applied
from a cyanide bath, but vacuum deposition, dipping,  spraying  and
mechanical (powder) plating are also used.

In the production of rechargeable nickel-cadmium and silver-cadmium
batteries, cadmium is the negative electrode.  The metal is also used in
brazing and fusible alloys.  Silver containing cadmium oxide is used in the
production"of electrical contacts, and cadmium intermetallic compounds with
sulfur, selenium or tellurium are used to produce semiconductors.

Cadmium compounds are used as pigments in glass, glazes,  paints, inks,
plastics, ceramics, and other products.  Cadmium is also used  as a
stabilizer in the production of plastics.

The cadmium concentration  in the  earth's crust  is between 0.1 and  0.5 ppm.
Cadmium is found in association with zinc  in  the form of cadmium sulfide.
Minerals containing cadmium are found  in zinc-rich basic, basaltic  rocks,
deposits of zinc-lead-copper sulfides, and  coal deposits.

Domestic production of cadmium  is dependent  upon  the  processing  of zinc
ore.  Currently U.S. demand  for cadmium  metal exceeds domestic  production.
                                    3-64

-------
Cadmium-bearing precipitate, an intermediate from electrolytic zinc ore
processing, is dissolved in a mixture of spent electrolyte from the zinc
plant, sulfuric acid and spent cadmium electrolyte as shown in Figure 3-22.
The cadmium is sponged to zinc by galvanic precipitation.   The sponge is
dissolved in spent cadmium electrolyte and sulfuric acid.   This solution is
mixed with electrolyte to form a cell electrolyte.  The solution is
electrolyzed by silver-lead anodes and aluminum cathodes.   Cathode deposits
are stripped and are washed, dried and melted under sodium hydroxide, which
prevents oxidation and removes waste metals (Zn,  As).  The metal is then
cast into commercial shapes.

Cadmium-bearing flue dust is mixed with concentrated sulfuric acid and the
mixture is roasted in a kiln or reverberatory furnace (Figure 3-23).  From
there it goes to a crusher.  The crushed mixture is then leached with water
and sulfuric acid to remove volatiles.  The resultant mixture is purified
to remove heavy metals.  It is filtered and purified a second time.  In
this process, three alternatives of recovery are possible.  Alternative 1
(Figure 3-24) is galvanic precipitation with zinc and is taken prior to any
purification.  Alternatives 2 (Figure 3-24) and 3 (Figure 3-25) are  taken
after filtering the second purification solution.  Alternative 2 is
galvanic precipitation with zinc.  Alternative 3 is electrolysis, which is
the more commonly used method.

Recovery of cadmium results in waste leach and purification solutions,
various metal cakes, and electrolytic slimes toxic recharge (Table  3-8).
Cadmium itself is a toxic metal and care must be exercised in its
handling.  Further study of the recovery of cadmium  for potential
regulation under Subtitle C is recommended.
                                   3-65

-------
   Spent Zinc
   Electrolyte
   Sulfuric Acid
         Zinc Dust
3
• **

•3
   Sulfuric Acid
                                 Figure 3-22

                            HIGH CADMIUM PRECIPITATE
 o
Vash-
Vater
                                        i
               Leaching  Process
                Copper Removal
                                   Filtration
                                  Precipitation
                                    > Cooper  Cnkc

                                    Filtrate
                                    Filtration

                                                 Dust
                                  Cadmium  Sponge
                                  (00%  Cd,  <5*  Zn)
              Leaching Process
                   45-G2°C
                                    Filtration
                             Cadmium Sulrate Solution
                                   (200 g Cd/L)
                                   Electrolysis
                                    Melting Pot
                                        T
                                    Cast Shape
                                       Precipi tat ion
                                                          Filtration
                                            T
                                      (to zinc plant)
Filter Cake
                                    3-66

-------
                               Figure 3-23

                         CADMIUM-BEARING  FLUE  DUST
Concentrated
Sulfuric Acid
v
J
Hixer
>
r
Roaster
450-600°C
Fumes

Uater 	
Sulfuric Acid'
                  Naliii
Iron Sulfate
Permanganante
Calcium hydroxide
Sodium Carbonate
                                                                     -Waste
                                                                      Uater
                                  Crusher
Leach Tank
->Waste Leach Solution
                                   Filter
                 -»Lead Sulfate (solid)
                            ^ Purification
                   Alternative #1
                   Galvanic Precipitation
                   Vith Zinc
                                           *Waste Purification Solution
                                  Filter
v^
iUe
te
Purification
\
/
F i 1 tor
,.

                    Copper Sulfide (solid)
                        Waste Purification
                             Solution
                                                    Iron Cake,  Containing
                                                         Impurities
                          Purified Leach Solution
                                    1
     Alternative #2
  Galvanic Precipitation
      vith Zinc
                   Alternative tt
                    Electrolysis
                                    3-67

-------
                                 Figure 3-24

                            CADMIUM PROCESSING
                            ALTERNATIVES (H & 2
                     GALVANIC PRECIPITATION VIT11 ZINC
                              Purified Leach
                                 Solution
                                   v
                          Galvanic Precipitation,
                              pi! = 2, 70°C
                                  Zinc
                              Precipitate
Wash Solution
(usu. NaOH)
                              Cadmium Sponge
Wash
                                 Compactor
                            Cadmium Briquettes
->Vaste Wash  Solution
                                      3-68

-------
      Figure 3-25

   CADMIUM PROCESSING
     ALTERNATIVE #3
      ELECTROLYSIS
 Purified Leach Solution
      Electrolysis
High Silicon-Iron Anodes
   Aluminum Cathodes
 Spent
Solution
       Melting Pot
           v
       Cast Shapes
             3-69

-------
u>
I
-J
o
                                                         Table 3-8


                                                CADMIUM PROCESSING WASTES

Process
Cadmium Recovery from
Precipitate
Cadmium Recovery from Flue Dust






A.

B.






Galvanic Precipitation with
Zinc
Electrolysis
Waste
Copper Removal Filter Cake
Post-Leach Filter Cake
Scrubber waste water
Leach Solution
Lead Sulfate Filter Cake
1st Purification Solution
Copper Sulfide Filter Cake
2nd Purification Solution
Iron Cake
Precipi tate
Caustic Wash Solution
Spent Electrolyte
Possible
R C
N
N
N
N
N
N
N
N
N
N
N
N
N
N
7
7
N
7
N
7
N
N
7
7
RCRA
I
N
N
N
N
N
N
N
N
N
N
N
N
Characteristics
T Comments
7
7
7
7
? Contains Lead
7
7
7
7
7
7
7
      * RCRA characteristics are Reactivity, Corrosivity, Ignitability,  and EP Toxicity  as defined  in 40 CFR 261

        Subpart C.


      N - Waste not expected to exhibit this characteristic.

      Y - Strong indication that waste would exhibit this characteristic.

      ? - Possibility that waste could exhibit this characteristic.

-------
                                REFERENCES

Cadmium Association, Cadmium Council, and International Lead Zinc Research
     Organization; Cadmium 77, Edited Proceedings First International
     Cadmium Conference San Francisco; Metal Bulletin Limited; London,
     England; 1977.

Mark, H.F., ed.; Encyclopedia of Chemical Technology, 3rd edition; Viley-
     Interscience, New York, New York; 1978.

U.S. Bureau of Mines; Mineral Commodities Summary 1987; U.S. Bureau of
     Mines; 1987.
                                   3-71

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                                  CESIUM
Cesium is a ductile alkali metal which melts near  room  temperature.   Its
properties are similar to those of other alkalis,  particularly potassium
and rubidium.  The metal oxidizes readily, and ignites spontaneously  in air.
The main use of cesium is as a fluid in several proposed  power generation
systems, including ion propulsion, and thermionic,  turboelectric,  and
magnetohydrodynamic systems.  All of these are strictly in the research and
development stage.  Cesium is also used in the production of vacuum  tubes,
photoelectric cells, and in vapor glow lamps.

The only producer of cesium in the United States is Kawecki Berylco
Industries, Inc., located in Revere, Pennsylvania.   The ore used to  obtain
cesium is pollucite (Cs-O-Al-OyASiO-) •  All of the pollucite used is
imported from the Tantalum Mining Corp., Manitobe,  Canada.

The primary method of cesium recovery from pollucite is shown in Figure
3-26.  Raw ore initially undergoes grinding and is mixed with water  to
produce a slurry.  Froth flotation is then used to produce a concentrate
which is acidified with sulfuric acid.  Vaste gangue from the flotation  is
discarded.  The acidified pump concentrate is treated with hydrofluoric
acid, aluminum sulfate, and a cationic reagent such as  a cocoamine acetate
for conditioning.  The conditioned pulp then undergoes  another stage  of
froth flotation,  through which relatively pure pollucite is obtained.   All
of the non-pollucite minerals are separated during the froth  flotation  and
are discarded as waste.  The concentrated pollucite is then digested  with
an acid, producing a cesium salt solution which is evaporated to yield  dry
cesium salt.  Acid digestion produces a solid waste stream containing the
metals and other  impurities which were generated during  final decomposition
of the pollucite.

The mining of raw ore for cesium recovery is straightforward  and  it  is
unlikely that the wastes produced are hazardous (Table 3-9).  The
                                   3-72

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                         Figure 3-26
           CESIUM RECOVERY FROM POLLDCITE ORE
Water.
Sulfuric Acid-
Hydrofluoric Acid-
Aluminum Sulfate—
Cationic Reagent—
Hydrochloric,
Hydrobionic, or-
Sulfuric Acid
                      Pollucite Ore
                           V
Ball Mill
Grinding
                              Slurry
Flotation}-
                Waste Solids
                            V
                              Pulp
 Mixing
                            \/
                          Froth
                        Flotation
                            \
              ^Non-Pollucite
              "^Mineral Waste
                              Pollucite Concentrate
  Acid
Digestion
                            \/
              -^Digester Waste
                              Cesium Salt Solution
                       Evaporation
                            V
                    Dried Cesium Salt
                            3-73

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                                                       Table 3-9

                                                     CESIUM WASTES
            Process
                        Uaste
                                                                      Possible RCRA
                                                                     Characteristic*
                                                      Comments
u>
Flotation

Froth Flotation


Acid Digestion

Hydrolysis
1) Uaste Solids

1) Non-Pollucite
   Mineral Uaste

1) Digestor Uaste

1) Uastevater
N   ?   N   ?

N   ?   N   ?


N   ?   N   ?

N   ?   N   N
           * RCRA  characteristics  are  Reactivity, Corrosivity, Ignitability and EP Toxiclty as defined in
             AOCFR 261  Subpact C.

           N - Waste  not  expected  to exhibit  this characteristic.
           Y - Strong indication that  waste would exhibit  this characteristic.
           ? - Possibility  that waste  could exhibit  this characteristic.

-------
processing and refining of cesium from the ore concentrate involves the use
of several acids and other chemical reagents.  The reagents used, as veil
as the quantities and characteristics of the wastes produced, were not
identified.  It is possible that the wastes produced during the final
stages of cesium salt refining may have hazardous characteristics.  Since
only one company processed cesium, production rates and raw material
consumption rates were withheld to protect company proprietary data.  Thus,
it is uncertain whether or not wastes are being produced in quantities
large enough to warrant further investigations.  Assuming substantial
quantities of wastes with potentially hazardous characteristics are being
generated, further investigation for possible regulation under Subtitle C
is recommended.
                                   3-75

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                                REFERENCES




Bureau of Mines, Mineral Commodities Summary; 1987.




Marks, H.F., Encyclopedia of Chemical Technology; 1978.
                                   3-76

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                                 CHROMIUM

Chromium is a strategic metal used in a number of industrial and commercial
applications.  Its most important properties are its resistance to heat,
abrasion, corrosion, and oxidation in alloys.  Approximately 50% of the
chromium consumed in the U.S. is used as an alloying metal for stainless
and heat-resistant steel.   Other uses for the metal are as a constituent in
pigments and dies, in the chemical and photographic industries, in metal
plating, as an alloying element in other ferrous and nonferrous alloys and
in refractory materials.

Currently, the United States has no chromium ore reserves.  The U.S. is
dependent on imports for all of its chromium consumption.  In 1986, 87,000
short tons of chromium were produced from secondary sources and 436,000
tons were imported.  Since the beneficiation and processing of chromium ore
has become technically and economically favorable for many of the countries
with chromium ore, the U.S. is importing increased amounts of refined
materials, such as ferrochromium.  The U.S. will continue to import
chromite ore for processing domestically, although the trend is to  import
less ore and more ferrochromium.

Chromite ore imported to the U.S. is used in basic refractories with
various mixtures of chromite and magnesia.  Roughly 80% of the basic
refractories are used_ in producing steel.  They are used  in open hearth
and in electric arc steelmakihg furnaces.  The wastes from the
manufacturing of these refractory materials are expected  to be minimal.
There is a possibility that they could exhibit hazardous  characteristics,
particularly EP toxicity.  This is due to leachable chromium from  the
chromite or from chromic acid, which is used as a binder  in some refractory
materials.  It is possible that there is no waste production,  because  all
materials could be recycled into the main product.
                                   3-77

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Ferrochromium is produced by the reduction of chromite vith coke in an
electric arc furnace.  Carbon, or silicon is used as the reducing agent,
depending on the quality of ferrochromium desired.  Slag consisting of
aluminum or silicon oxides is the significant waste expected from this
process.  This slag is not expected to exhibit any hazardous
characteristics.

The chromite refractory industry could generate wastes with hazardous
characteristics (Table 3-10).  Therefore, further study of that industry
for potential regulation under Subtitle C is recommended.
                                   3-78

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                                                         Table 3-10

                                                       CHROMIUM WASTES
                                                                        Possible  RCRA  Characteristics*

                 Process                         Waste                  R    C    I    T     Comments


        Chromite  Refractory               Refractory Wastes             N    ?    N    ?    Chromium and Chromium Acid
          Manufacturing


        *  RCRA  characteristics are Reactivity,  Corrosivity, Ignitability and  EP Toxicity as defined in 40CFR 261
          Subpart  C.
u>
.Jj       N  -  Waste  not  expected to exhibit this  characteristic.
"°       Y  -  Strong indication that waste would  exhibit this characteristic.
        ?,  -  Possibility that waste could exhibit this characteristic.

-------
                          COLUMBIUM AND TANTALUM

Columbium (Niobium) and tantalum are generally found together in nature as
oxides and hydroxides in association with other metals such as tin,
titanium, and the rare earth elements.  Columbium and niobium are synonyms
for the same element.  Niobium is the name officially adopted by the
International Union of Pure and Applied Chemistry, but the metallurgical
industry has persisted in the use of the term columbium,  which is used in
this report.  Ores of commercial significance include pyrochlore
((Na,Ca)2(Nb,Ti,Ta)2[OF,OHJ7), and columbite-tantalite ((Fe,Mn)(Nb,Ta)206),
(Marks, 1978).  Pyrochlore is the most abundant mineral containing
columbium and is found most often in carbonatite and alkalic rocks.
Pyrochlore contains very little tantalum.  Columbite and tantalite are at
the ends of an isotnorphous series varying in composition from columbium
dominated to tantalum dominated with the name indicating which metal
dominates.  Columbite-tantalite is obtained as a by-product of other metal
mining, mainly tin.  Tin slags produced from foreign tin smelting are also
an important source of tantalum.  The U.S. resources of columbium and
tantalum are low grade and are at present uneconomical for mining.
Therefore all columbium and tantalum production is from imported raw
materials (EPA, 1983).  There are currently 7 companies operating 8
columbium and tantalum producing plants in the U.S.  These plants are
located in the eastern, central, and western United States, and process
less than 5 million pounds of columbium and tantalum raw materials annually
(Bureau of Mines, 1987).

Columbium is a relatively lov density metal exhibiting high strength at
high temperatures, retained plasticity at cryogenic  temperatures, and
corrosion resistance.  The principal use of columbium is as an  additive  in
steel making to improve the mechanical properties  of  the steel  alloy.
Columbium is also an  important alloying element in nickel-,  cobalt-, and
iron-based superalloys used in gas  turbine engine  components  and other
aerospace applications.  Columbium/tantalum alloys are used  in  the  chemical
                                    3-80

-------
and electrical industries as plating material because of its  resistance to
corrosion when in contact with strong acids and oxidants.

Tantalum has similar chemical and physical properties to that of columbium,
and like columbium it is used in making high temperature alloys (super
alloys).  Tantalum carbide is used in tools and dies because  of its
hardness and strength.  Tantalum oxide is a component of high grade optical
glass.  The most vide spread use of tantalum is in the production of
electronic components, particularly capacitors.  Tantalum also finds use as
a construction material in the chemical industry because of its resistance
to corrosion and its high thermal conductivity and mechanical strength
(Miller, 1959).

Because columbium and tantalum co-occur in ores and slags, they must first
be separated.  Separation and processing consists of 4 primary operations:
    •  digestion of the ore (formation of niobium and tantalum salts);
    •  separation of niobium from tantalum;
    •  separation of impurities reduction of the salts to the elemental
       form (metal);
    •  fabrication (production of ingots, bars, or plates).

Plants in the U.S. vill include either the first tvo operations, the last
two operations, or all four operations.  The first tvo operations are shown
in Figure 3-27.

Digestion is necessary to release the niobium and tantalum (as salts) from
the ores.  This is almost universally done by leaching the ores with
hydrofluoric acid (HF) to form columbium and tantalum salts.  A residual
solid waste (gangue) is produced and wet scrubbers used  to control acid
mists produce a wastewater stream.
                                   3-81

-------
                        r
                            H,0
 Concentrate* —• HF
                       I (Scrubber

                      / •
                  ij f\ t  •
                   3 •  • Waatewater 1
—I "*• I   '   H
rh-U   f
                                Waatewater 2

r^n
\H




M^s
•••/I i

HF 	 -
•




i.
>

                     Banen Solids
                     to OitpoiaJ or
                     Sluiry Walar
                     to Wai ta
                     Treatment
                                              —I  Baffan I
                                                   Solvent
                   Waalewater
                   ,»
»
Ralflnale Waala
Waatewater  3
                                                          Precipitation
Waelewaler
                                                                                                   •
                                                                                                 4 f
                                                                                         Precipitation
• Wattewater lo
r* Traalment and/or
  Oitchitr^e
           Generalized flow sheet  for comnerclal  production  of Cb and Ta  salts showing water use and
           orltfliitf  of contact waste streama.                                                                CDM
                                    Figure 3-27  columblum-Tantalum Processing     	 ZTTTZL'^^^l"

-------
Tantalum is separated from columbium by exploiting the varying solubility
of each metal in methyl isobutyl ketone (MIBK) as a function of hydrogen
ion content of the mother liquor.  At low normalities of HF,  tantalum is
selectively extracted into the MIBK, and subsequently the normality of the
solution is increased for extrication of columbium into fresh MIBK.  The
wasted mother liquor (raffinate) and wastewater from a wet scrubber that
controls releases of organic vapors are the tvo waste streams produced in
this operation.  Deionized vater is used to extract the niobium and
tantalum from the MIBK.

Niobium and tantalum are then each precipitated as salts.  Niobium is
precipitated by addition of ammonia to produce columbium oxide.  Tantalum
is precipitated by addition of potassium chloride or fluoride to produce
potassium fluortantalate (K-SaltjK-TaF,) or by the addition of ammonia to
produce tantalum oxide.  The salts are filtered and the discarded  filtrate
is a wastewater stream.  Drying of the salts produce other wastewater
streams, because of the use of vet scrubbers to control dust emissions.

Tantalum metal powder is produced by sodium reduction from K-Salt.  Sodium
reduction consists of placing alternating layers of the K-Salt and
elemental sodium in a reactor, igniting the material to initiate the
exothermic reduction process, passing the material through a magnetic
separator to remove iron impurities picked up in the reaction vessel, and
then leaching with water and acid to produce the purified product.  Waste
streams are generated from leaching, the magnetic separator, and wet
scrubbers on the reactor.

Ferro-columbium, nickel-columbium, and columbium metal are produced by
aluminothermic reduction of columbium oxide.  The aluminothermic reduction
processes are similar to the sodium reduction process with  the exception
that aluminum is the reductant added to the columbium oxide.   In the
aluminothermic reaction, potassium  chlorate is added  to  improve  the
exothermic release of heat and  the mixture  is ignited with magnesium  metal.
Ferro-columbium produced from pyrochlore is converted  to  columbium oxide by
                                   3-83

-------
a chlorination process.  This oxide is used as a feed to alumino  thermite
reduction.  During carbon reduction, also known as the Balke  process,  fine
carbon is added to the oxides of niobium or tantalum and the  mixture is
heated to 1,800°C in a vacuum.  This produces the metal carbide that is
subsequently converted to niobium or tantalum metal by reaction with an
excess of the metal oxide.  The process releases carbon monoxide.   It  is
assumed that leaching of the metals produced by the aluminothermic and
carbon reduction processes is similar to that of the sodium reduction
process.   This would generate wastewater streams.

Electrolytic reduction is used for tantalum where potassium fluorotantalate
is directly reduced to tantalum metal at a carbon cathode.   The cathode and
plated metal are pulverized and the carbon leached out with acid thus
generating a waste stream.

Fabrication generally involves an ultra purification step to maximize  the
malleability and ductility of columbium and tantalum.  The most widely used
purification process is electron beam melting.  A high voltage, low current
electron beam is focused on the metal which causes melting and vaporization
of contaminants.  The melted metal is cooled in water for resolidification
and casting.  This water is wasted representing another waste stream.

EPA has extensively studied the niobium and tantalum processing industry  in
order to propose Clean Water Act effluent guidelines and new source
performance standards for direct dischargers, or pretreatment standards  for
discharge to municipal severs (EPA, 1983).  The  following information  is
based on the information collected by EPA, and refers  to the flow sheet  in
Figure 3-24.

Uastewater 1, in Figure 3-24 vhich consists of the gangue waste and the  wet
scrubber wastewater in the digestion stage, is acidic  (pH 2),  has
concentrations of fluoride greater  than  TO,000 mg/1,  contains  copper,  lead,
and zinc at concentrations from 300 to 1,000 mg/1, cadmium at  40 mg/1,  and
1,2-dichloroethane and chloroform concentrations at  or  around  100 ug/1.
                                   3-84

-------
There is no data on the specific characteristics of vastevater 2,  the
solvent extraction wet scrubber waste, because EPA sampled only a  mixture
of this water and wastewater 1.

Wastewater 3 raffinate waste had chloroform concentrations ranging from 34
to 240 ug/1, chrome at 1,000 mg/1,  lead averaging 500 mg/1,  selenium 45
mg/1, zinc 433 mg/1, and arsenic 27 mg/1.   This wastewater had a pH of
approximately 2.

The most notable characteristic of wastewater 4 from niobium precipitation
was its high ammonia content (approximately 500 mg/1).

Data exist on the characteristics of a mixture of vastewater 5 and the
leaching wastewater from columbium and tantalum reduction.  The average
chloroform and 1,2-dichloroethane concentrations were 61 and 23 ug/1,
respectively.   Chrome, nickel, and lead occurred at 1 mg/1, and fluoride
concentrations were 3,000 mg/1.

Clearly many of these waste streams have RCRA hazardous waste
characteristics, however, all of these streams are presumably regulated
under the Clean Water Act.  These wastes, once  treated, will likely meet
the exemption of 40 CFR 261.3(a)(2)(iv) and otherwise not have Subpart C
characteristics (Table 3-11).  However, the sludges generated from the
treatment of these wastes may have hazardous characteristics and  therefore
further study for potential regulation under Subtitle C of RCRA is
recommended.
                                    3-85

-------
I
CO
                                                        Table 3-11

                                                 COLUMBIUW, TANTALUM WASTES
Process
Digestion
Solvent Extraction
Precipitation
Calcination
Waste
Scrubber, cooling liquor
Barren solids
Scrubber liquor
Raffinate
Precipitation Barrens
Scrubber liquor
Possible
R C
N
N
N
N
N
N
7
7
7
?
7
RCRA
I
N
N
N
N
N
N
Characteristic*
T Comments
,;
7
7
7
'




       * RCRA characteristics are Reactivity, Corrosivity, Ignitability,  and EP Toxicity  as  defined  in 40 CFR 261
           Subpart C.

       N - Waste not expected to exhibit this characteristic.
       Y - Strong indication that waste would exhibit this characteristic.
       ? - Possibility that waste could exhibit this characteristic.

-------
                                REFERENCES

Bureau of Mines, 1987.  Mineral Commodity Summaries, 1987.

Bureau of Mines, 1985.  Mineral Facts and Problems, 1985 Edition.

EPA, 1983.  Development Document for Effluent Limitations Guidelines and
     Standards for the Nonferrous Metals: Point Source Category, Volume
     III.  EPA-440/1-83/019-6.

Lyakishev, 1985.  Niobium in Steels and Alloys.  Lyakishev, N.P., Tulin,
     N.A., and Pliner, Yu.L.  Comanhia Brasileira de Metalurgia e
     Mineracao, 1985.

Marks,  1978.  Encyclopedia of Chemical Technology.  Mark, H.F. et al.
     editors, Wiley Interscience, New Yorki 1978.

Miller, 1959.  Tantalum and Niobium, Miller, G.L., Academic Press Inc.,
     London, 1959.
                                   3-87

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                                   GALLIUM

 Gallium is one of only four metals which can  be a  liquid near room
 temperature,  and it has the longest temperature range  in which  it is a
 liquid of any element.  Roughly 95 percent  of the  gallium used  in the
 United States is in chemical compounds, mainly gallium arsenide and gallium
 phosphide.  These semiconducting compounds  exhibit electroluminescence and
 are used in semiconductors, light emitting  diodes,  laser diodes, and in
 other electronic applications.
                              *
 There is one  producer of gallium from a domestic mine  in the United States.
 Husto Exploration Limited operates a mine and extraction plant  for gallium
 and germanium at St.  George, Utah.  This is reportedly the  only operation
 in the world  producing these metals as primary products.  Another company,
 Eagle-Picher  Industries produces gallium from imported and  recycled
 materials in  Quapav,  Oklahoma.   Actual production  figures for  these plants
 were withheld to protect company proprietary  data, but the  Musto plant  has
 a rated capacity of 9,000 kilograms of gallium per year.  Imports of
 gallium materials in 1986 were estimated at 17,000 kg  with  reported
 consumption being 15,000 kg.

 The process used by the Musto Co. at St. George, Utah  for gallium and
 germanium recovery is outlined in Figure 3-28. Ore is leached  with
.sulfuric acid, sulfur dioxide and fluorspar.   The  fluorspar would  react
 with the sulfuric acid to form hydrofluoric acid.   The solids  that  remain
 after leaching are washed to remove the leach liquor and  then  are  placed in
 a tailings pond.  If the washing is effective, the tailings (waste  1)  would
 not exhibit any hazardous characteristics.   Otherwise, acid remaining in
 the tailings could cause them to exhibit  the characteristic of corrosivity
 (pH less than 2).  The leach liquor from the leaching process  contains
 copper which is removed by cementation.   In the  cementation step,  the
 solution is brought into contact with iron scrap.   The copper  in solution
 exchanges with the metallic iron leaving metallic copper precipitate and
                                    3-88

-------
                                          Figure 3-28

                                PROCESS  FLOW  SHEET
                   FOR GALLIUM AND GERMANIUM  PRODUCTION
 SULFURIC
  ACID

  SULFUR
  DIOXIDE
     ORE
    LEACH
FLUORSPAF

    IRON 	~j
WASH
TAILINGS TO POND
 CEMENTATION
HYDROGEN
SULFIDE
                      COPPER
                                   (PRODUCT)
GERMANIUM
PRECIPITATION
                                           SULFURIC ACID
                                           SALT
LEACH
DISTILLATION
                          GERMANIUM
                         PRECIPITATION
                                        STILL
              SOLVENT
              EXTRACTION
GALLIUM
PRECIPITATION

h
                                         PURIFICATION
                                              GALLIUM
                                             HYDROXIDE
                FERROUS
                SULFATE
                SOLUTION
                    ZINC SULFATE
                      SOLUTION
08% PURE
GERMANIUM
OXIDE (PRODUCT)
                                                                  COMINCO LTD.
                                                                  PROPRIETARY
                                                                  TECHNOLOGY
                                     ELECTROLYSIS
                                   ^GALLIUM

                                    (PRODUCT)

-------
the iron in ionic form in solution.  The cemented copper  is  removed  and
sold as a product.

The next step in processing of the leach liquor is to precipitate germanium
by reacting the solution vith hydrogen sulfide.  The germanium is removed
and sold or refined and sold.  The leach liquor goes onto a  solvent
extraction step where gallium is extracted from the leach liquor by  an
organic solvent.  The leach liquor is now barren ferrous  sulfate solution
of lov pH which could exhibit hazardous characteristics and  could be a
problem if disposed.  The gallium in the organic solvent  is  stripped out*
into another aqueous solution and the organic solvent is  recycled.  The
solvent is typically dissolved in an organic carrier, often  kerosene.  When
any of the solvent in the organic carrier is disposed, it would be
ignitable.  Ammonia is added to the strip solution, which causes
precipitation of gallium hydroxide.  As shown in Figure 3-28, the solution
left after the gallium hydroxide precipitates is described as a zinc
sulfate solution.  The exact composition and disposition of  this material
was not specified in the references.

The gallium hydroxide passes onto purification and proprietary electrolysis
stages with the final product being gallium metal.  No information was
available on the characteristics or disposition of any wastes from those
processes.

The plant in Quapaw, Oklahoma processes primarily secondary materials and
therefore is not included in this study.

The characteristics of the wastes from gallium production are summarized  in
Table 3-12.  Several of these streams may exhibit hazards characteristics.
Therefore further study of gallium production  for possible regulation under
subtitle C is recommended.
                                   3-90

-------
                                                   Table  3-12

                                                GALLIUM WASTES
Process
Husto Exploration
Leaching
Solvent Extraction
Gallium Precipitation
Possible RCRA*
Characteristics
Waste R C I T
Tailings N ? N N
1) Ferrous Sulfate Solution N ? N ?
2) Solvent and carrier N N ? N
Zinc Sulfate Solution N N N ?
Comments

Hay not be waste
Hay not be waste
* RCRA characteristics are Reactivity, Corrosivity, Ignilability and EP Toxicity as defined in 40CFR 261
Subpart C.

N - Vaste not expected to exhibit  this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

-------
                                REFERENCES




Bureau of Mines, Mineral Commodities Summary, 1987.




Marks, H.U., Encyclopedia of Chemical Technology, 1978,
                                   3-92

-------
                                 GERMANIUM

Germanium is a metalloid with highly desirable electrical and optical
properties.  Its transparency to infrared wavelengths,  high refractive
index, low dispersion, and moderate strength account for its widespread use
in infrared optics and fiber optic systems.   It is also used as a
semiconducting material in electronics,  and  as a semiconductor substrate.
Small amounts of germanium are also used in  catalysts,  chemotherapy,  and
metallurgy.

Germanium is produced by three refineries in New York.,  Oklahoma, and
Pennsylvania.  Germanium-bearing residues from zinc ore processing at
Clarksville, Tennessee, are sent to Belgium  for germanium recovery.  At St.
George, Utah, germanium is recovered as one  of two primary products along
with gallium at Musto Exploration's Apex mine.  Most coals contain small
quantities of germanium, which become concentrated in the ash and dust
during coal burning.  While the recovery of  germanium from coal ash and
flue dust is not currently economically practical, it was practiced for
several years in the 1950's, and it is considered a possible future source
of germanium.

A simplified process flow diagram for the recovery of germanium during zinc
ore processing is shown in Figure 3-29.  The ore  is roasted and sintered
(solidified).  Sintering fumes, containing oxidized germanium, are
collected in a bag house.  The sinter fumes are leached vith sulfuric acid,
producing a leaching solution containing  the germanium.  The germanium  is
then selectively precipitated by the addition of  zinc dust.  The solids
remaining after leaching, as well as the wastewater leaving  the
precipitation process, may contain small  amounts  of arsenic and other
metals.  The solids will be recycled to maximize  the recovery  of germanium.

The germanium recovery process used by Musto Exploration at  St. George,
Utah is outlined schematically in Figure  3-30.  In  this  process  the  ore  and
                                   3-93

-------
                      Figure 3-29

   RECOVERY OF GERMANIUM DURING ZINC ORE PROCESSING
                  Zinc Recovery from
                  Zinc Ore  Processing
                          V
 Germanium oxide-containing  fumes  from zinc  sintering
Leaching.
Reagents
Precipitation.
  Reagents
                          V
  Leaching
                          V
Precipitation
                           V
                 Crude germanium oxide
_^> Leaching
    Waste
J^Wastewater
                           3-94

-------
                                           Figure 3-30

                                   PROCESS FLOW SHEET
                       FOR GALLIUM AND  GERMANIUM PRODUCTION
i-n
     SULFURIC
      ACID

      SULFUR
                   ORE
    FLUORSPAR-


        IRON 	-|
                                         WASH
                                                      TAILINGS TO POND
               CEMENTATION
HYDROGEN
SULFIDE
                      COPPER
                    - CEMENT
                     (PRODUCT)
GERMANIUM
PRECIPITATION
                                               SULFURIC ACID
                                               SALT
                                        LEACH
                              GERMANIUM
                             PRECIPITATION
DISTILLATION
                                                     STILL
                                                        TO
                  SOLVENT
                  EXTRACTION
                                 GALLIUM
                                 PRECIPITATION
                                        PURIFICATION
                                                  GALLIUM
                                                 HYDROXIDE
                    FERROUS
                    SULFATE
                    SOLUTION
                                  ZINC SULFATE
                                   SOLUTION
08% PURE
GERMANIUM
OXIDE (PRODUCT)
                                                                 COMINCO LTD.
                                                                 PROPRIETARY
                                                                 TECHNOLOGY
                                                                            GALLIUM
                   ELECTROLYSIS  [	-'
                                   (PRODUCT)

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fluorspar are leached with sulfuric acid and sulfur dioxide.   The fluorspar
will form hydrofluoric acid which assists in leaching the germanium and
gallium.  The residual solids after leaching are washed and disposed in a
tailings pond.  These tailings could still contain acid if the washing is
not adequate.  Copper is removed from the leachate by cementation on iron
and is sold as a byproduct.  Hydrogen sulfide is used to precipitate the
germanium.  Gallium is recovered from the remaining supernatent liquid.
The precipitated germanium is refined by leaching and distillation with a
still residue being discarded as waste.  The characteristics of the still
residue were not described in literature, but it could be acidic.

The recovered germanium oxide precipitate needs, to undergo refining to
produce the high purity germanium most applications require.  As shown in
Figure 3-31, crude germanium oxide is chlorinated with concentrated
hydrochloric acid to produce germanium tetrachloride in solution.  Solid
impurities are separated and discarded as waste or further processed.
Filtrates and all wash waters are consolidated and sent for further
germanium recovery.  The relatively pure germanium chloride is then
converted to solid germanium dioxide through hydrolysis with deionized
water.   This process produces vastewater which must be discharged properly.
The germanium oxide is reduced to germanium metal with hydrogen at a
temperature of roughly 760°C.

The major contaminants of concern in the wastes produced during germanium
recovery operations are arsenic and other metals.  The arsenic enters  the
process as a constituent of  the sintering fumes recovered during zinc  ore
processing.  In addition, germanium processing uses acids producing wastes
which are potentially corrosive.  Since  the wastes produced during  the
recovery and processing of germanium may have hazardous characteristics
(Table 3-13), further investigation for  possible  regulation under  Subtitle
C is recommended.
                                   3-96

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                        Figure 3-31


               PROCESSING OF CRUDE GERMANIUM
Hydrochloric.
    Acid
Deionized.
  Water
Hydrogen-
                   Crude Germanium Oxide
                           V
   Chlorination
                           V
                    Germanium Chloride
                            \/
    Hydrolysis
                            V
                      Germanium Oxide
Chemical Reduction
                            \
         V
                      Germanium Metal
x.Waste Solids
                              3-97

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vO
CO
                                                       Table 3-13

                                                   GERMANIUM  WASTES
Process
Germanium from Zinc
Residues
Leaching of zinc
sintering fumes
Precipitation
Husto Exploration
Leaching
Refining
Chlorination
Hydrolysis
Possible RCRA Characteristic*
Waste R C I T Comments

1) Leaching waste N ? N ? Hay contain
arsenic
1) Vastevater N ? N N

Tailings N ? N N
Still residue N ? N ?
1) Waste solids N ? N ?
1) Vastewater N ? N N
            *  RCRA characteristics are Reactivity,  Corrosivity, Ignitability and EP Toxicity as defined in
              AOCFR 261  Subpart  C.

            N  -  Waste not  expected to  exhibit  this  characteristic.
            Y  -  Strong indication that waste would  exhibit  this characteristic.
            ?  -  Possibility that  waste could exhibit  this characteristic.

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                                REFERENCES




Bureau of Mines, Mineral Commodities Summary, 1987.




Bureau of Mines; Mineral Facts and Problems, 1985.




Mark, H.F., Encyclopedia of Chemical Technology, 1978.
                                    3-99

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                              GOLD AND SILVER

Gold and Silver will be described here together since  most  of  the  processes
to recover one will recover the other.  Differences  in processing  will  be
discussed when they occur.   Also, both metals are  often found  together  in
nature, with many mines producing both gold and silver.   Whether a mine is
classed as a gold or silver mine is usually based  on which  metal is the
greater contributor to the economic value of production.

Gold has been known and used by man since the earliest times.   It  is most
commonly found in nature in its "native" or metallic state.  The only
minerals containing gold are compounds with tellurium  as tellurides.
Calaverite (AuTe-) and Sylvanite ((Au,Ag)Te-) are  examples.  Gold  may be
found as particulate accumulations in some gravels (placer  deposits) and in
veins (lode deposits), usually with quartz and pyrite.  Gold and silver
occasionally occur together as a natural alloy known as electrum.   Gold is
often found in base metal lode deposits and is a common byproduct  of copper
and lead production.  It is prized for its beauty, corrosion resistance,
and ductility among other properties.  Gold is widely  used  as  a store of
value and for other monetary purposes.  It is also used in  jewelry,
industrial (mainly electronics), the arts, and in  dental applications.
Domestic mine production was estimated at 3.6 million  troy  ounces for 1986
by the U.S. Bureau of Mines, in the 1987 "Mineral  Commodity Summaries".  In
the USBM "Minerals Yearbook 1985," 93 percent of mine  production was
estimated to be from precious metal ores, five percent from base metal
ores, and two percent from placers.  Gold mining is the fastest growing
mineral industry in the United States with over 250 mines in operation or
in construction.  Most gold activity  is in the western U.S.

Silver has also been known from ancient times,  there  is evidence  that
silver was separated from lead as early as 3,000 B.C.   Vhile some  native
silver is found, it is less noble than gold and many  silver compounds  are
found in nature.  It occurs very often  in base metal  deposits and  such
                                   3-100

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deposits accounted for 70 percent of 1985 production according to the
"Minerals Yearbook 1985".  The other 30 percent was produced  from precious
metal ores.  Domestic production of silver was estimated at  35 million troy
ounces in 1986 by the Bureau of Mines in the "Mineral Commodity Summaries,
1987".  Approximately 160 mines produce silver with 70 percent of
production coming from five states:  Arizona, Idaho, Missouri, Montana, and
Nevada.  There is little current exploration on development  activity for
silver due to low prices.

Several processes exist for recovering gold and silver from  their ores.
These include gravity separation, amalgamation, froth flotation,
cyanidation,  and smelting.  Any given deposit will generally require the
use of more than one of the above in combination.  In addition there are
several methods of cyanidation leaching and recovery of gold and silver
from solution.  This report will individually discuss various processes and
the wastes they produce, with the knowledge that several processes may be
combined at any precious metal plant.

Gravity Separation

Gold deposits often contain free gold ranging in size from several microns
up to one or more cm (nuggets).  If the nuggets are larger than
approximately 0.5 mm, they can be separated from the host rock by their
density.  Gold has a density of 19 g/cm  while most rock has  a density of
2.7 g/cm .  Devices that separate by density range  from the simple gold pan
to the sluce box, common in the last century,  to shaking tables  and jigs.
The latter two items have been used for many years  and are still in  common
use today.  Gravity separation is used at most placer mines and  at some
"lode" or vein deposits.  In the case of  the placers, the waste  product  is
gravel which would not be expected  to exhibit any  hazardous
characteristics.
                                   3-101

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Amalgamation

If the free gold in a placer deposit is finer than approximately  0.55 mm,
they often are not cleanly separable from all of the ore  minerals by
density alone.  The fine concentrate stream from a gravity separator often
contains several dense minerals as well as fine gold.   This product  is
often called "black sand" because its color.   Many placer operations
recover fine gold from such a concentrate by  amalgamation.  Amalgamation,
an ancient process, entails the dissolving of gold or silver in mercury.
The resulting alloy, called amalgam is relatively soft and will adhere
readily to other pieces of amalgam or to mercury.  In the amalgamation
process, mercury is added to the ore or black sand and is mixed violently,
often in a grinding mill, to assure maximum chance of contact between gold
and mercury.  After a mixing period, all of the material  is placed in a
separator that allows the amalgam and any excess mercury  to agglomerate and
separate from the rest of the ore.  The waste black sand  is discarded.
This waste might contain some excess mercury although the process is
operated to minimize such losses.  The amalgam is cleared and excess
mercury is squeezed out.  The amalgam is then retorted to remove the
mercury and leave the gold.  The mercury is recovered and reused.  A
general flowsheet is shown in Figure 3-32.

Cyanidation

While density separation can be used to recover coarse gold and
amalgamation can recover finer gold from placers, cyanidation leaching is
the primary means of recovery of fine gold and silver from vein or  "lode"
type deposits.  In  this process, solutions of sodium or potassium cyanide
are brought into contact with an ore which may or may not have required
extensive preparation prior to leaching.  Gold and silver are dissolved by
cyanide in solutions of high pH  (pH > 10) in  the  presence of oxygen.  There
are three general methods of contacting ores  with leach solutions,  heap
leaching, vat leaching, and agitation leaching.   These methods are
discussed below.  After dissolving  the metal  values  the leach solution  is
                                   3-102

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                     Figure 3-32

                     GOLD-SILVER
                 GRAVITY/AMALGAMATION
Coarse
Nuggets
Gold-
Dore'
                    Placer  Type  Ore
                          1
                        Washing
                    Size Separation
Density (Jig)
 Separation
                         Table
                          _V
                      Amalgamation
   Retorting
                           Clays
                           Coarse Rock
  Fine Rock
                           Fine Sands
                         -^Waste
                           Black Sand
->Hg Recycle
                           3-103

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separated from the ore and the gold and silver is removed from solution.
Again several methods exist for doing this and each is described below.

Cyanidation-Ore Preparation

Preparation of an ore for leaching can include size reduction, froth
flotation concentration, roasting, agglomeration, and other processes
depending on the nature and mineralogical composition of the ore.  Of these
processes, roasting is the one with the greatest chance of producing a
waste which could exhibit hazardous characteristics.  In deposits
containing sulfide minerals,  gold may be trapped in the sulfide grains,
often in pyrite.   The ore is roasted in an oxidizing atmosphere which
converts the sulfide minerals to oxides breaking up their physical
structure to allow leaching solutions to penetrate and dissolve the gold.
Sulfur, in the form of sulfur dioxide, is removed from the offgas.  The
offgas will also contain oxides of volatile elements such as arsenic if  it
is present in the ore.  The oxide would be removed from the offgas as a
flue dust which could exhibit the characteristic of EP toxicity.  However,
few operations in the U.S. are roasting gold or silver ores.

The ores that are leached with cyanide vary widely in metal concentrations
and, therefore, value.  Low value ores are treated by the lowest cost
process, heap leaching, while high value ore are treated by agitation
leaching to maximize recovery of metal values.

Cyanidation - Heap Leaching

Heap leaching for gold and silver is very similar  to dump leaching  for
copper.  A general flowsheet is shown in Figure  3-33.  The  ore  is piled  on
a gently sloping impervious leaching pad that has an  integral solution
collection system.  The leaching solution is applied  to  the  top  of  the pile
by sprinklers.  The precious metals are dissolved as  the solution trickles
through the pile.  The metal bearing solution (pregnant  liquor)  is
collected on the impervious pad and pumped to a  gold and silver  recovery
                                   3-104

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                   Figure 3-33

                  GOLD-SILVER
                   LEACHING
Dore' <-
                  Heap or Vat

                      Ore
                  Heap or Vat
                 Carbon Column
               Carbon Stripping
                     Gold
                Electrowinning
                      I
Refining
                        •Spent  Ore
                                            Barren Liquor
                                            Recycle
                       3-105

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circuit and following rejuvenation returns for reuse  after  the  metals are
removed.  The leaching process vill continue until  no  more  precious metal
is extracted.  Typical operation vill involve leaching  for  several months
on each heap.  The process is relatively inexpensive  and  can be operated
for less than two dollars per ton of ore.   The disadvantages are that as
much as half of the gold and silver may not be extracted  either because the
leach liquor never contacts the precious metal or because the pregnant
liquor is trapped in blind channels in the pile.   The waste  from this
process vill be the pile of spent ore and  leaching solutions after the
completion of the leaching process.  The pile may contain residual leach
liquor and some operators may attempt to recover  this prior  to  washing the
spent ore and transporting it to vaste containment  sites.

Cyanidation - Vat Leaching

Vat leaching is used vhen greater solution control than that afforded by
heap leaching is necessary.  In this system, prepared ore is placed in a
vat or tank and flooded with leach liquor.  The solution  is continuously
cycled through draining from the bottom of the vat, then  to gold recovery,
rejuvenation and return to the top of the vat.  The process is more
expensive than heap leaching because the material must  be removed from the
vat at the end of the leaching process.  The primary  advantage is better
solution contact but channelization and stagnant  pockets  of solution are
problems almost as severe as in heap leaching vhen the  solution is drained
from the vat.  Some of the trapped solution will  be recovered when the
solids are removed from the vat.  Wastes from this process would be  the
solids and any left over solution.

Cyanidation - Agitation Leaching

High value ores, those containing more  than 0.1  troy ounce of gold or
equivalent silver, are treated by agitation leaching.  The ore vill  be
crushed and ground in vater to form a slurry.  Cyanide is normally added  at
the grinding mill to begin the leaching process.   More cyanide may be added
                                   3-106

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to the leaching tanks.  The residence time in leaching is  generally greater
than 24 hours with some ores being leached for 72 hours or more.   Silver
ores tend to require longer leaching times.   The method of recovering the
precious metal from solution determines how the solution is separated from
the solids.   If the Merril-Crowe or carbon-in-column metal recovery process
are used, the leach liquor will be washed out of the solids usually by a
combination of counter-current decantation and filtration  washing,  with
water.   This produces a concentrated wash solution and recovers the maximum
pregnant liquor from the solids.  The resultant slurry will contain very
little cyanide or gold and would not be expected to exhibit hazardous
characteristics.   If carbon-in-leach or carbon-in-pulp metal recovery is
practiced, the slurry may be discarded without washing. The carbon should
remove all of the precious metals, and the solution is recovered from the
tailings treatment and recycled to the process.

Cyanidation - Metal Recovery - Merrill-Crowe

Recovery of precious metals from pregnant leaching solutions is
accomplished by several different means.  The primary difference is whether
the metal is removed by precipitation with zinc or by adsorption on
activated carbon.  Zinc cyanide is more soluble  than gold or silver cyanide
and if pregnant liquor is contacted with metallic zinc the zinc will go
into solution and the gold and silver will precipitate.  Most operations
using zinc precipitation in the United States use some variation on  the
Merril-Crowe process as shown in Figure 3-34 in which  the solution  is
filtered for clarity then vacuum deaerated to remove oxygen to decrease
precious metal solubility.  The deaerated solution  is  then mixed with  fine
zinc powder to precipitate the precious metals.  The solids including  the
precious metals are removed from  the solution by  filtration and  the
solution is sent back to the leaching circuit.   The solids are melted  and
cast into bars.  If silver and gold are present  the bars  are called  dore.
In most cases, the metal is then  sent  to an off-site refinery.
                                   3-107

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                     Figure 3-34

                     GOLD-SILVER
   AGITATION LEACHING WITH MERRILL-CROVE RECOVERY
Dore',e-
                         Ore

                          I
                        Size
                      Reduction
                      Leaching
                      Washing
                     Filtration
                     Deaeration
                      Zinc Dust
                    Precipitation
                         _v
                    Solid/Liquid
                     Separation
                         _v
Refining
Casting
                   -> Tailings
                      Solids
                       Zn CN solution
                          3-108'

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Cyanidation - Metal Recovery - Activated Carbon Loading

There are three ways that precious metal leaching solutions  are brought
into contact with activated carbon.  These are carbon-in-column (C-I-C),
carbon-in-pulp (C-I-P) and carbon-in-leach (C-I-L).   Carbon-in-column
systems are used at heap and vat leach operations and in other situations
where the leaching solution is separated from the solids being leached
prior to precious metal recovery.  The leaching solution is  then passed
through a series of columns containing beds of activated carbon.  The gold
and silver are adsorbed as cyanide complexes on the  surfaces of the carbon.
After passing through the columns the solution is returned to the leaching
circuit.  When the carbon in a column is loaded with precious metals, the
column is switched to a stripping circuit as described below.

In many agitation leach plants, the gold is recovered from the leached
material before the solution is separated from the solids.  In the
carbon-in-pulp system as shown in Figure 3-35, the leached pulp passes from
the last stage of the leaching circuit into another series of agitation
tanks.  Each tank contains activated carbon granules.  The slurry flows
from tank to tank in series while the carbon is retained by screens.  When
the carbon in the first tank is fully loaded with precious metals, it is
removed and sent to the stripping and reactivation circuit,  the carbon in
the other tanks is moved ahead one stage and new carbon is added to  the
last stage.  The carbon therefore moves in a counter current fashion  to  the
leached slurry.  The leached slurry is finally sent to  the tailings  area
for dewatering.

Carbon-in-leach is very similar  to carbon-in-pulp except  that  the carbon is
in the leaching tanks instead of a separate recovery circuit.   One
advantage of C-I-L over C-I-P is that some cyanide  is  released  when  gold
adsorbs on carbon which will be available  for more  leaching.   Another
advantage is that fewer agitated tanks are needed since the separate
recovery circuit is eliminated.  A disadvantage  is  that the  agitation is
more aggressive in the leach circuit causing more attrition  of  the  carbon
                                   3-109

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                               Figure 3-35

                          GOLD-SILVER -  LEACHING
                 CARBON-IN-PULP VERSUS CARBON-IN  LEACHING
Carbon-in-Pulp

               Cyanide
Ground Ore  i
Slurry

]
0
r
0
••^MHHB
]
f\
r
f*^
                             oo
               Leach Tanks
                                      I
                     oo
                                     Carbon Tanks
                                                                  waste
                              -Carbon
                                  Loaded Carbon to  Stripping
Carbon-in-Leach
Ground Ore
                   Cyanide
                     1
Slurry
I
                                 ob
     Loaded Carbon to Stripping
                                              I
                                                 T
                                                                >To waste
                                                                •Carbon
                                       3-110

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than in C-I-P, thus, the finely abraded carbon and its load of precious
metals may be lost, reducing recovery and increasing costs due to increased
carbon replacement.  Both C-I-P and C-I-L show this disadvantage when
compared to carbon-in-column recovery.

Cyanidation - Metal Recovery - Activated Carbon Stripping

Gold stripping from loaded activated carbon is usually done vith a hot,
concentrated alkaline cyanide solution, sometimes including alcohol.  These
conditions favor the desorbtion of the precious metals into the stripping
solution.  The solution then goes into an electrovinning cell where the
precious metals are plated out, generally on to a steel vool cathode.  The
solution is recycled to the stripping stage and the cathode is sent on to
refining.  Some operations refine the steel vool on site to make dore;
while others ship it directly to commercial refineries.  The primary waste
from carbon stripping is the spent stripping solution.

Precious Metals from Base Metal Smelting

Gold and silver are also recovered in the refining processes for base
metals, primarily lead and copper.  The recovery of precious metals in a
lead refinery is a normal part of the operation called "desilverizing".
This process takes advantage of the solubility of precious metals in molten
zinc which is greater than their solubility in molten lead.  Lead from
previous stages of refining is brought in contact vith a zinc bath either
in a continuous operation or in batches.  The zinc absorbs the precious
metals from the lead and the lead is  then passed onto a dezincing
operation.  The zinc bath is used until it contains 5,000-6,000  troy ounces
of precious metal per ton of zinc.  The zinc bath  is  then  retorted  to
recover zinc by distillation.  The zinc is returned to the desilverizing
process and the "retort metal" left is treated by  cupellation  to produce
dore bullion.  In the cupellation step, the base metals in the retort  metal
are oxidized with air and removed from the precious metals.  The oxides are
                                   3-111

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the precious metals.  The oxides are all treated for the recovery of their
various metals.  The dore is then sent to refining.  No wastes are produced
by this process.

A major source of precious metals from the copper industry is the cell
slimes from the electrolytic refining of copper.  The slimes are
periodically removed from the cells in the refinery for treatment.  The
first stage of treatment removes the copper in the  slimes by acid
leaching, either as is or after roasting.  The decopperized slimes are then
placed in a furnace and melted with a soda-silica flux.  The siliceous slag
formed in this melting is removed and air is blovn through the molten
material.  Lime is added and a high lead content slag is formed which is
combined with the siliceous slag and returned to the copper anode casting
furnace.  Fused soda ash is next added to the furnace and air is again
blovn through the melt forming a soda slag which is removed and treated  to
recover selenium and tellurium.  The remaining dore in the furnace is
removed and sent to refining to recovery the precious metals.  No wastes
are produced by this process.

Precious Metal Refining

There are many different refining operations for gold and silver depending
on the composition of the materials in the feed.  The most basic operation
is "parting" which is the separation of gold and silver.  Parting can be
done electrolytically or by acid leaching.  In either case, the silver is
removed from the gold.  Further treatments may be necessary to remove other
contaminants.  These treatments have the potential to produce wastes with
hazardous characteristics, primarily corrosivity since strong acids are
used.

Summary

In summary, it must be noted that there  is considerable controversy about
the hazard potential and environmental fate of cyanide  in wastes  from
                                   3-112

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data readily available to characterize these wastes as hazardous or
non-hazardous.  Based upon the study above as summarized in Table 3-14,
refining is the only other stage of processing that could be expected to
produce wastes with hazardous characteristics.  Therefore, it is
recommended that further study including data collection, analysis, and
evaluation of the gold and silver production industry be limited to cyanide
leaching and precious metal refining for potential regulation under
Subtitle C.
                                   3-113

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                                                      Table 3-14

                                                 GOLD AND SILVER  WASTES
u>
             Process
Vaste
Possible RCRA Characteristic*
 R   C   I   T      Comments
Gravity/Amalgamation
Leaching
Refining
Tailings
Tailings (spent rock)
Leach Solution
Wastes
N N
? N
? N
7 7
N
N
N
N
? Possible Mercury
Contamination
N Possible Cyanide
Carry Over
N Cyanide
? Hany Acids
             *  RCRA characteristics are Reactivity,  Corrosivity,  Ignitability and EP Toxicity as defined in
               40 CFR 2.61  Subpart C.

             N  -  Waste not  expected to exhibit  this  characteristic.
             Y  -  Strong indication that waste would  exhibit  this  characteristic.
             ?  -  Possibility that  waste could exhibit  this characteristic.

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MV_Misc/Proc. Descriptions/67
                                REFERENCES

McQuiston, Shoemaker, Gold and Silver Cyanidation Plant Practices, Volume
     1, 1975.  Society of Mining Engineers of AIME.

Biswas, Davenport, Extractive Metallurgy of Copper, 1976.  Pergamon Press.

U.S. Bureau of Mines, Mineral Commodity Summaries, 1987.

U.S. Bureau of Mines, Minerals Yearbook, 1985, Volume 1.

U.S. Bureau of Mines, Mineral Facts and Problems, 1985.
                                   3-115

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                                  INDIUM
Indium is a soft, silver-white metal which is highly malleable and ductile.
Indium exhibits a highly plastic character and will retain this property at
cryogenic temperatures.  When heated, indium will react with air to form
In.O.,.  Heated indium will also react readily with halogens, sulfur,
phosphorous and metalloids.  When in combination with metals and
metalloids, intermetallic and semiconducting compounds are formed.  Indium
is electroplated easily in baths, such as cyanide, sulfate,  and sulfamate.
Indium can undergo large amounts of deformation by compression, does not
work-harden and cold welds easily.  Addition of indium to industrial metals
increases strength and hardness, improves resistance to corrosion, and will
result in a product with increased anti-seizure properties.

In nature, indium is estimated to occur at about the same concentration as
silver in the earth's crust, but is usually found to be less than 0.05 ppm.
In the copper mining region of Arizona, chalcopyrite contains approximately
35 ppm indium.  The highest indium concentrations are found in sulfide
casserite (tin) deposits.  Indium is also associated with zinc, and zinc-
lead deposits.  Notable concentrations of indium can be found around
copper, zinc, and zinc-lead smelters, due to fine dust.  Otherwise indium
is found as a trace element in other mineral deposits.

In 1986, 40% of the indium produced was used in the electronic, electrical
component industry, and another 402 was used in the solders, alloys, and
coatings industries.

Indium is used in several metal alloys. Indium additions generally  result
in lower boiling points, greater strength and hardness, and corrosion
resistance.  An indium (24%) - gallium (76%) alloy  is used  in nuclear
reactors to circulate gamma activity.  Indium is also used  in neutron-
monitoring badges.  An indium (15%) - silver (80%)  - cadmium  (5%) alloy  is
used in control rods.  When indium is combined with copper, silver  and
                                   3-116

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gold, the alloys formed are used in specialty brazing.   Indium is also used
in dental alloys.  Indium is used in the production of  bearings for use in
heavy duty, high speed engines.  These bearings are in  piston-type aircraft
engines, high-performance automobile engines and diesel engines.   Coatings
of indium are used in the electronics industry to increase strength and
reduce corrosion.  Indium gaskets are used in cryogenic machinery due to
their plastic character.  Indium gaskets are also used  for glass to metal
seals.  Extensive research and development is being done to explore other
applications of indium and its alloys.

The most common sources of commercial indium are zinc,  lead, copper and
lead-zinc smelter intermediates.  In these smelting processes, indium is
liberated from the ore to the flue dusts and leaching residues.  Recovery
of indium from these mediates is accomplished by processes that are
different, depending on the source of indium.  These processes include
chloride slag, residual dross, leaching from cadmium flue dust,
hydrochloric acid leaching, and mineral source indium processing.

The most common method of indium recovery is associated with lead-zinc
metal production as shown in Figure 3-36.  At temperatures between 380°C
and 390°C, lead chloride, sodium chloride and zinc chloride are added  to
the molten lead-zinc.  A chloride slag, containing 112 to 14X  indium,  is
skimmed from the kettle.  The chloride slag is leached with aqueous
sulfuric acid at 70°C to 85°C.  This will create a residue containing
approximately 500 ppm indium.  Zinc dust is added  to the solution and  an
indium sponge is formed.  The sponge is digested in sodium hydroxide  at
150°C to 190°C.  This will leave a crude metal.  This crude indium metal,
97.5X pure, is melted at 205°C with pure zinc chloride.  This  renders  an
indium that is 99.55Z pure.  The metal is electrolyzed to give 99.99X pure
indium.

Recovery from residual dross from the production of lead or lead  alloys,  as
outlined in Figure 3-37, begins with  the addition  of sodium hydroxide and
sodium sulfide to the residual dross at 590°C  to give  indium  sulfide.   This
                                   3-117

-------
                                Figure 3-36

                      INDIUM FROM LEAD-ZINC SMELTING
               LEAD CHLORIDE, SODIUM CHLORIDE,  ZINC CHLORIDE
Zinc-Lead
  Metal —
       /  Nad,  ZnCl2
Sulfuric
  Acid
Zinc
Dust
  Sodium -
Hydroxide
        Kettle
    380°C - 390°C
 Molten
Zinc-Lead
                                                 ->  Waste Salt Solution
                                   I
                               Chloride Slag
                         Containing 112-14* Indium
                                    I


Leaching Process
70°C - 05°C


       Solution
Containing the 11-14% In
                                     I
                               Indium Sponge
                                    i
        Digester
     150°C - 190°C
                            Crude Indium Metal
                                97.57. Pure
                                    1
                                    T
                               Indium Metal
                                99.99% Pure
                            Residue *£ 500 ppm  In
                            Sent to Pb refinery
                                                         Waste Soln  (Some  In)
>Waste Soda Solution
     (No In)
Pure
loride
Kettle
205°C


                                                      Waste Slag
                                     3-118

-------
                                Figure  3-37
                      LIBERATION OF INDIUM FROM LEAD


                     Sodium Hydroxide,  Sodium Chloride
       Lead,
Lead Bearing Alloys
Sodium Hydroxide
Sodium Sulfide
Sulfuric
  Acid


Kettle
3708c - A15°C
\
t

U
                              Residual Dross
                                   1
    590°C
                                   T
                           Indium Sulfide, In-S-

                                    ]/
Oxidizcr
\
t
                               Indium Oxide
                                   1
Electrolysis
                              Impure Indium
                             More Treatment
                    * Lead Metal
                      Lead Alloy

                     Uaste Salt Solution
                       Waste Sodas
Waste and
                     Electrolytic Slimes
                                      3-119

-------
indium sulfide is converted to oxide.  The oxide is dissolved in sulfuric
acid and the solution is electrolyzed to remove impurities,  residual
metals, and yield pure indium.

Figure 3-38 is a flow sheet for the process by which indium can be
recovered from cadmium-bearing flue dusts.  The flue dust is leached for
cadmium recovery and the residue treated with sulfuric acid.  This solution
is then treated with sodium sulfate at pH 3.2 to precipitate the indium
metal.  When the leaching and proceeding steps are repeated approximately
98.72 indium can be recovered.  The precipitate is boiled with sodium
hydroxide to yield pure indium metal.

Indium recovery by leaching flue dust is achieved by first treating the
dust with hydrochloric acid (see Figure 3-39).  After this oxidation, iron
powder is added with sodium carbonate and the indium is precipitated along
with arsenate.  Sodium hydroxide is added to dissolve the arsenate and
indium hydroxide is precipitated.  This process exhibits very good indium
recovery.

Indium source material is leached using sulfuric or hydrochloric acid,
starting with a reduction bullion, or electrolytic slime.  Once in
solution, the indium is recovered as a sponge on zinc or aluminum.

Recovery of indium from fumes, flue dusts or residues utilizes strong acids
and caustic sodas.  Therefore, possible wastes produced are waste acid and
soda solutions, spent starting materials, arsenates from flue dust
leaching, and electrolytic slimes (Table 3-15).  Further investigation
should be made into these processes  to determine if possible regulation
under Subtitle C is necessary.
                                   3-120

-------
Cadmium 	
Bearing Flue Dust
Sulfuric
  Acid -
 500°C
   Sodium
 Peroxydisulfate
   pH - 3.2
Wash
Water
  Sodium
Hydroxide
                              Figure  3-38
                           INDIUM RECOVERY FROM
                           CADMIUM-BEARING FUMES
Cadmium
Recovery
                                               T
•Fume  Residual  for  Recycle
 •  ' • -> Cadmium
                                 Flue Dust
                                   1
Dilution
                             Dilution Solution
                                   Indium
                                    Metal
                   Waste Dilution Solution
                        Waste Water
                   Waste Soda Solution
                                   3-121

-------
                               Figure 3-39
                            INDIUM RECOVERY BY
                            FLUE DUST LEAGUING
Hydrochloric
   Acid
•V

Flue Dust
1
Leaching
Process
•s.

                     Solid Residue
                             Oxidized Solution
Iron Powder
Sodium Carbonate
Mixing and
Filtration
-> Waste Solution
                     Precipitated Indium and Arsenate
                                     I
 Sodium
Hydroxide
Mixing and
Filtration
 -»Vaste Soda
                               Precipitated
                             Indium  Hydroxide
                                 In(OH)3
                                       3-122

-------
I
t~*

l*>
                                                       Table 3-15


                                                 INDIUM PROCESSING WASTES
Process
Chloride Slag Processing


Lead Dross Processing


Flue Dust Processing in
Association with Cadmium
Recovery
Flue Dust Leaching Process


Leaching of Bullion or Slimes


Waste
1) Solids from Leaching
2) Soda Solution
3) Slag
1) Soda Solution
2) Electolytic Acid
3) Electrolytic Slime
1) Dilution Solution
2) Filter Uashwater

1) Leach Residue
2) Spent Filtrate
3) Soda Solution
1) Leached Residue
2) Kettle Slag
3) Spent Leachate
Possible
R C
N
N
N
N
N
N
N
N

N
N
N
N
N
N
7
7
N
7
7
N
7
N

N
N
?
N
N
7
RCRA Characteristics
I T Comments
N
N
N
N
N
N
N
N

N
N
N
N
N
N
7
7
7
N
7
? Hay contain lead
7
7

7
7
? May contain arsenic
7
7
7
      *  RCRA characteristics are Reactivity, Corrosivity, Ignitability, and EP Toxicity as defined in  40  CFR 261

        Subpart C.


      N  - Waste not expected to exhibit this characteristic.

      Y  - Strong indication that waste would exhibit this characteristic.

      ?  - Possibility that waste could exhibit this characteristic.

-------
                                REFERENCES

Mark, H.F., ed.; Encyclopedia of Chemical Technology; 3rd Edition; Uiley-
     Interscience; New York., New York; 1978.

Smith, I.C., Carson, B.L., and F. Hoffmerster; Trace Metals in the
     Environment, Volume_5-Indium; Ann Arbor Science Publishers, Inc.;  Ann
     Arbor, Michigan; 1978.
                                   3-124

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                              IRON AND STEEL

More than 90 percent of the iron ore mined is used to manufacture
semifinished steel, which is processed further into a number of steel
products.  The manufacture of iron and steel involves a number of
processes, including mining and beneficiation of iron ore,  agglomeration,
coking, ironmaking, and steelmaking.

Iron ores have been deposited in a variety of igneous, metamorphic, and
sedimentary environments.  These ores are oxides,  carbonates, silicates,
and sulfides, and may be capable of being shipped  as mined to ironmaking
furnaces.  In the U.S., however, most are lower grade ores that must be
beneficiated prior to shipping.

The Lake Superior district in Minnesota, Michigan, and Wisconsin is the
major source of iron ore in the United States.  In 1986, 97 percent of  the
usable ore produced in the U.S. came from Minnesota and Michigan.  The
remainder was produced in California, Wyoming, Utah, Missouri, Alabama, New
York, and Texas.  Relatively little ore from the Lake Superior district is
shipped directly to ironmaking facilities.  The ore from most areas of  the
country generally must be concentrated prior to ironmaking.  The iron and
steel industry is in a depressed state with less than 60 percent of raw ore
capacity and less than 75 percent of steel making capacity being used.

A general flow diagram for the production of steel from raw ore  is shown  in
Figure 3-40.  There are several stages to this process beginnning  with
beneficiation.  The methods of beneficiation for iron ores vary
considerably.  Some ores are greater, then 60 percent  iron, and only
crushing and blending are necessary  to prepare them  for further  processing.
Other operations, such as screening and concentrating, are needed  to
produce a usable material in some areas.  The  types  of processes used
differ with  the structure and mineral content  of  the  ore.
                                   3-125

-------
                              Figure 3-40

                              IRON  AND  STEEL
                       GENERAL PROCESS  FLOW DIAGRAM
                                 iron ore
                                  mining
limestone quarries
limestone
                                       rav ore
  iron ore
beneficiation
crushing & screening
             coal
concentrate
           I
         /
agglomeration
                      ingot
                      molds
                      ingots
                     coke ovens
                                       sinter or/pellets
                                   blast
                                  furnace
                                   _V
                                       pig iron
                                steelmaking
                                 furnaces
                     slag processing
continuous
casting
machine
V
(
              blooms, billets
                 or slabs
                                     3-126

-------
Magnetite is the main iron-bearing mineral in many ore deposits,  including
those in the Lake Superior district and in the northeastern United States.
When magnetite occurs in lower grade deposits, the ore is ground  very fine
and the concentrate is separated magnetically from the gangue.   Magnetic
separation is generally done with the ore in a water suspension.   The
tailings from magnetic separation would consist of mostly silicate rocks
and are not expected to exhibit hazardous characteristics.

Hematite and hematite-magnetite mixtures are found in ores in Alabama, the
Lake Superior district, and some of the western deposits.  The ore can be
high in clay and, therefore, may need to be washed to remove the clay and
concentrate the iron.  The clay wastes are not expected to exhibit any
hazardous characteristics.

Lover grade ores containing mineral types other than magnetite may be
concentrated by washing, jigging, heavy-media separation, or flotation
processes.   Jigging involves washing by pulsing vater upwards and downwards
through the crude ore to stratify the ore.  The gangue moves upward and  the
ore concentrate is removed in the underflow.  Wastes include the wastewater
used for washing and gangue.

Heavy-media separation utilizes a liquid medium with a specific gravity
between the specific gravities of the gangue and  the mineral to be
concentrated.  In the case of iron ore, the medium is non-toxic and
consists of a water slurry of finely ground ferro-silicon or magnetite.
Generally,  the gangue is lighter than the mineral and floats, while  the
mineral sinks.  The only waste from this process  would be  the tailings.

Froth flotation is commonly used to concentrate low grade  iron ores.   Fatty
acids, soaps, or sulphonates are added  to a liquid suspension of  finely
ground raw ore.  The iron minerals are  attracted  to air  bubbles which cause
the iron to float to the top of  the solution, where it can  be collected.
                                   3-127

-------
The gangue and flotation solution are usually sent to tailings ponds for
settling, and the liquid is discharged to receiving waters.

Ores being sent to blast furnaces for iron making need to be permeable to
allow for good gas flow through the system.  Concentrates in raw ores that
are very fine must be agglomerated prior to being used as feed stock for
blast furnaces.  The main types of agglomeration used are sintering,
pelletizing, and briquetting.

Sintering involves mixing iron-bearing material such as ore fines, flue
dust, or concentrate with fuel such as coke breeze or anthracite.  The
mixture is spread on beds and the surface is ignited by gas burners.  The
heat fuses the fine ore particles together into lumps, called sinter.  The
sinter is sized and fines are recycled.  Sintering is an operation that
commonly recycles wastes from other iron and steel manufacturing processes.
Any fines or air pollution control dusts produced are usually recycled back
into the sintering process.  Air emissions, mostly fugitive dusts, have
caused problems at some plants.

Pelletizing involves forming pellets from raw ore or concentrate ("green"
pellets) then hardening the pellet by heating.  Solid fuel may be added  to
the concentrate to promote the heating necessary to harden the pellet.
Limestone, dolomite, soda ash, bentonite, and organic compounds may be
added as binders or to increase pellet strength.  The pellets are generally
sized and the undersize fraction recycled back into the process.

In briquetting, the ore is heated, then, while hot, pressed into
briquettes.  The briquettes are cooled,  then sent to  the blast  furnace.

The reducing agent used in blast furnaces is coke.  Coke is the  hard,
vesicular solid product of the destructive distillation of coal.  When  coal
is heated in the absence of oxygen the volatile components of  the coal  are
driven off.  The volatile components include water, naptha, coal  tars,  and
ammonia, among others.  The solid left behind is mainly carbon.  Good
                                   3-128

-------
metallurgical coking coal will form a porous but strong solid that can
support the weight of a tall column of material in a blast furnace without
crushing.  The coal used for coke generally must be prepared at least by
the process shown in Figure 3-41 before going to the coke ovens.   Over 99
percent of the domestic coking operations use "byproduct" ovens in which
the byproducts of coking are collected for use.  These plants heat
bituminous coal in ovens in the absence of heat to drive off the volatile
compounds which are collected as shown in Figure 3-42.  The coal is
converted to coke in the oven, cooled by quenching, sent to a crushing,
screening, and blending operation.  The fines from screening are usually
used as feed stock in sintering or pelletizing.

The gas from coking operations is sent through a series of coke gas
cleaning operations that recover coal tar, ammonia compounds, naphthalene,
and light oil.  Cleaning of the exhaust gas begins with a liquid scrubber,
primary cooler, and electrostatic precipitator.  These processes remove
coal tars that may disrupt other recovery operations.  The gas is processed
further to recover ammonia compounds and light oils.  The cleaned gas  is
used as a fuel in the coke ovens or in other locations in the steel  plant.
The other byproducts are sold as organic chemical  feed stocks.

The vastevaters generated from these processes are usually used in coke
quenching.  Host organic byproducts are combined with  the coal tar.  Wastes
generated include coke quenching solution and may  include spent scrubber
water and cooling tower blowdown.  These wastewaters may contain  toxic
organic compounds and heavy metals.  They are usually  treated  prior to
discharge to receiving waters.

Limestone is prepared prior to being used in blast  furnaces  for ironmaking.
The raw limestone is crushed and screened to produce  a  prepared limestone
that is the appropriate size.  The oversize fraction  is  recycled  into  the
grinder and the undersize fraction is usually used  in  concentrate
agglomeration.
                                   3-129

-------
                   Figure 3-41

                  IRON AND  STEEL
                 COAL PREPARATION
                       coal
vater-
 oil-
                     breaking
                       _V
                     screening
                    pulverizing
                     blending
density
control
                        V
                     to coking
                       ovens
                   fines  to agglomeration
                   fines to aaalortieration
                            3-130

-------
                             Figure 3-42

                           IRON AND STEEL
                               COKING
              flushing
               liquor
flushing liquor
   decanter
        tar
  dehydrator
     tar
   settling
    tanks
    phenol
   extractor
    ammonia
     still
     still
     waste
NH,
                            gas
         primary
         cooler
        exhauster
       precipitator
         ammonia
         absorber
                           _V
          final
          cooler
        light oil
        scrubber
hydrogen
sulfide
scrubber
        exhaust
          gas
                                               quenching
                                                 station
                                             >waste
                                             water
                         coke
                        crusher
                                                   V
                       screening
                        station
     coke
""^screening
      to
  agglomeration
                                                    V
                                               metallurgical
                                                   coke
                                    3-131

-------
In ironmaking, agglomerated iron ore, prepared limestone,  silica and coke
are placed into the blast furnace and heated air is blown  into the furnace.
The limestone and silica form a fluid slag which combines  with other
impurities.  The slag is separated from the molten iron and sent to a slag
reprocessing unit.  Most iron from the blast furnace is transferred to the
steel making furnaces in the molten state.  A small fraction is used to
make iron castings or is cast into pigs for re-melting.  Fine particles in
the exhaust gas are removed and the dust recycled into the process.  The
exhaust gas has fuel value and is burned to preheat the blast air.

There are three major steelmaking processes:  the basic oxygen furnace
(EOF), the electric arc furnace, and the open hearth furnace.  The
different furnaces are better suited to producing different types of steel,
and are suited to using particular raw materials.  Electric arc furnaces
are mostly used for scrap processing, and the open hearth process is being
replaced with BOF steel making due to speed and lower costs.  The raw
materials may include molten iron metal, pig iron, scrap,  directly reduced
iron,  iron ore, or iron bearing material such as pellets or mill scale.
Lime,  dolomite, fluorospar, or limestone may also be added as fluxing
agents.  Sometimes other metals, in various forms, are added  to produce a
steel alloy.  More frequently, alloying elements are added in the ladle
between steel making furnace and casting.  The impurities rise to the  top
of the molten steel as slag.  The slag and molten metal are separated, with
the slag sent to a reprocessing unit and the molten steel sent to either
ingot  molds or to a continuous casting machine producing blooms, billets,
or slabs.  The exhaust is collected and the flue dust removed.  The  flue
dust is either recycled into the furnace or sinter plant or disposed of as
waste.  The refractory materials used to line blast furnaces  and steel
making furnaces must be replaced periodically.  Some of these refractories
are made with chromium oxide and some use chromic acid as a  binder,  making
used refractories potentially EP toxic wastes.

Much of the slag from iron manufacturing and all of the slag  from  steel
manufacturing is air cooled.  The cooling of the slags is occasionally
                                   3-132

-------
accelerated by spraying the warm slag vith vater.  This water either
evaporates, or is allowed to drain from the slag pit in the same manner as
rain water.  The air cooled slag is crushed and iron-bearing material is
removed magnetically and returned to the furnaces.  The crushing of slag
may produce fine particles which can escape into the atmosphere.  After
crushing, the slag is screened and shipped, mainly for use as an aggregate.
Some of the hot slag from blast furnaces is poured into vater to produce
expanded slag, a lightweight aggregate.  This cooling water is handled
similarly to the vater sprayed on air cooled slag, i.e., allowed to drain
off.  Blast furnace slag 15 also processed to produce granulated slag, a
vitreous product used in cement manufacture and as a soil conditioner.
Granulated slag is produced by breaking up the molten slag with jets of
water.  This process requires larger amounts of water than other slag
processing techniques, and, therefore, the water used is recycled.  The
vater in these systems is occasionally chemically cleaned.

Many potential vastes from the manufacture of iron and steel are
beneficially used or reused or are actually recycled (Table 3-16).
However, due to the size of the industry,  the management of the wastes  is
not clearly defined.  Further study for potential regulation under  Subtitle
C is recommended.
                                   3-133

-------
                                                        Tabu   -16

                                                  IRON AND STEEL  WASTES
I
H*
U>
*>
Process
Ore Beneficiation
A. Magnetic
separation
B. Vashing
C. Jigging

D. Heavy-Media
Separation
E. Flotation
Sintering
Coking


Ironmaking

Steelmaking

Slag Processing
Vaste

1) Gangue
2) Vastevater
1) Wash water
1) Gangue
2) Wash water
1) Gangue
2) Separation Solution
1) Tailings
Air Emissions
1) Coke Quenching Solution
2) Scrubber Water
3) Cooling Tower Slowdown
1) Flue Dust
2) Used Refractories
1) Flue Dust
2) Used Refractories
1) Cooling Water
Possible RCRA
R C I

N
N
N
N
N
N
?
N
N
N
N
N
N
N
N
N
N

N
N
N
N
N
N
7
N
N
N
N
N
N
N
N
N
N

N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Characteristic*
T Comments

?
7
7
7
7
7
7
?
N
7
?
7
? Hay be recycled
?
? May be recycled
7
7
     * RCRA characteristics  are Reactivity,  Corrosivity, Ignilability, and EP Toxicity as defined in 40 CFR 261
         Subpart C.

     N - Vaste not expected  to exhibit  this  characteristic.
     Y - Strong indication  that waste would  exhibit  this characteristic.
     ? - Possibility  that waste could exhibit  this characteristic.

-------
                                REFERENCES

Marks, H.F., ed.; Encyclopedia of Chemical Technology, 1978.

Russell, C.S. and V. J. Vaughan; Steel Production:  Processes, Products,
    and Residuals, 1976.

U.S. Bureau of Mines; Mineral Commodities Summaries, 1987.

U.S. Steel; The Making, Shaping and Treating of Steel, 1971.
                                   3-135

-------
                                 MAGNESIUM

The uses of magnesium are tied to its properties.  It is a lightweight
metal with a relatively high strength vhich is used in auto parts and hand
tools.  It is also a constituent in aluminum alloys and is used in
explosives and flares as it is pyrophoric in powdered form.  Magnesium acts
as a reducing agent in the manufacture of titanium and zirconium and is a
catalyst in the formation of a number of organic compounds.

Magnesium is fairly abundant in the earth's crust and in the sea.  It is
currently recovered from dolomite deposits in Washington, from brines from
the Great Salt Lake, and from seavater.  It is also recovered from titanium
processing residues.  Four companies produced metallic magnesium in 1987.
They were Amax Magnesium Corp. in Rowley, Utah; Dow Chemical Company in
Freeport, Texas; Northwest Alloys Inc. in Addy, Vashington; and Oregon
Metallurgical Corp. in Albany, Oregon.  The first two companies used an
electrolytic process to recover magnesium from natural brines.  The third
company processed dolomite by silicothermic reduction.  The Oregon
Metallurgical Company electrolytically recovered magnesium from magnesium
chloride generated in their titanium production process (Bureau of Mines,
1985; Bureau of Mines, 1987).  These processes are described below and
outlined in Figures 3-43 to 3-45.
             •s
                         ^,
There are two basic electrolytic processes in use, the Dov process and  the
NL process.  The Dow process is used at the Dow Chemical Plant in Freeport,
Texas, and the NL process is used at the Utah plant in Rowley operated  by
Amax Magnesium.  It is not reported which process is  in use in the Oregon
facility.

The Dow process involves adding calcium hydroxide to  seawater  to produce a
solid magnesium hydroxide.  This solid precipitate is separated  from
solution, reslurried, and the magnesium hydroxide converted to magnesium
chloride by neutralizing the slurry with hydrochloric and  sulfuric acid.
                                   3-136

-------
wash vater
  water
                           Figure 3-43

               MAGNESIUM  -  DOV ELECTROLYTIC  PROCESS


                                  uolomitic lime (CaO-MgO)
                   seavater
                     .V
                           kiln
                 flocculator
                  thickener
                            _V
                                                  Ca(OH).
                          slaker
               overflow
                         Mg(OH),
                   filters
                 reslurrying
neutralizer
              wash water
                    to treatment
                    (neutralization)
                    prior to ocean
                    discharge
                         MgCl,
  filter
                     _V
-^solids
                                     HCL furnace
                 evaporator
                  Dov cell
                                   '2'
                         Mg crystals
                 recasting
              molded or cast
                 magnesium
                                3-137

-------
              Figure 3-44

       MAGNESIUM - AMAX PROCESS
           Great Salt Lake
                water
CaCl,
•Cl,-
             evaporation
                ponds
                    brine
 flocculator
              thickener
                —^solids
            concentrator/
             spray dryer
                    MgCl,
heated reactor
                    molten MgClj
            electrolytic
                cells
                    Hg crystals
               casting
           cast magnesium
                metal
                  3-138

-------
                  Figure 3-45

        MAGNESIUM -  SILICOTHERMIC PROCESS
Dolomite
  Kiln
    CaOMgO
                   Scrap Iron
                   Arc Furnace
Grinder
                  •SiO
                  -Coke
FeSi
                   Briquetter
                     Furnace
                 •(CaO)2 Si02 Residue
                           Mg crystals
                     Casting
                    metallic
                       Mg
                       3-139

-------
The waste solids are removed and the magnesium chloride solution
evaporated.  The crystals are placed in a Dow Electrolytic cell, where
metallic magnesium crystals and chlorine gas are formed.   The chlorine gas
is converted to hydrochloric acid and reused in the neutralization step.
The magnesium crystals are recast into metallic magnesium ingots or other
shapes.  Wastes from this process include thickener overflow and filter
wash and solids from the second filtration operation.  The wastewaters are
neutralized prior to ocean discharge.  The disposition of the filter solids
is unknown.

The NL electrolytic process uses calcium chloride to remove impurities from
the feed brine.  These solid impurities are removed and the solution
concentrated.  The concentrated magnesium chloride solution is solidified
as magnesium chloride crystals in a spray dryer.  The crystals are sent to
a heated reactor to which chlorine is fed to remove further impurities.
The purified, molten magnesium chloride is sent to the electrolytic cell,
where metallic magnesium crystals are formed.  The crystals are then recast
into ingots.  Wastes produced include thickener solids and possible solid
residue from the heated reactor vessel.  Waste management methods for  these
wastes are not known.

Dolomite can be processed by the silicothermic process to yield metallic
magnesium.  The carbonates in dolomite are converted to oxides  by
calcining, then ground and mixed with ferrosilicon.  The mixture is
briquetted, then charged into a retort furnace.  The resulting  magnesium
crystals are separated from the slag and recast into ingots.  The only
identified waste from this process is the furnace slag.  The disposition  of
this slag is unknown.

Although this industry is relatively small, current waste management
methods are not clear (Table 3-17).  Further study of  this industry  for
possible regulation under Subtitle C is, therefore,  recommended.
                                   3-140

-------
                                                       Table 3-17

                                                    MAGNESIUM  WASTES
            Process
Waste
                                                                        Possible RCRA
                                                                      Characteristic*
                    Comments
u>
i
            Dow  Electrolytic
            NL Electrolytic

            Silicothermic
1) Thickener Overflow


2) Filter Wash Water


3) Filter Solids


1) Thickener Solids

1) Furnace Slag
N     ?   N   N   Neutralized  and
                  discharged

N     ?   N   N   Neutralized  and
                  discharged

N     N   N   ?   May contain  trace
                  heavy metals

N     N   N   ?

N     N   N   ?
            * RCRA characteristics  are  Reactivity,  Corrosivity,  Ignitability and EP Toxicity as defined in
              40CFR 261  Subpart  C.

            N - Waste not expected  to exhibit  this  characteristic.
            Y - Strong indication  that  waste would  exhibit  this  characteristic.
            ? - Possibly that waste could exhibit  this  charcteristic.

-------
                                REFERENCES
Bureau of Mines, 1987 Mineral Commodity Summaries, U.S. Dept.  of Interior,
    1987.

Bureau of Mines, 1985 Minerals Yearbook, U.S. Dept. of Interior, 1985.

Mark, H.F., ed., Encyclopedia of Chemical Technology, John Uiley & Sons,
    1983.

Pidgeon, L.M., et al., Magnesium, American Society for Metals, 1946.

Roberts, C. Sheldon, Magnesium & Its Alloys, John Viley & Sons, 1960.

Strelets, Kh.L., Electrolytic Production of Magnesium, Refer Publishing
    House, 1977.
                                    3-142

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                                 MANGANESE

Manganese is a gray metal which is hard and brittle,  and resembles iron.
Manganese occurs in three forms, alpha, beta,  and gamma.  The alpha and
beta forms are brittle, yet stable.  The gamma form is ductile and
unstable, yet can be stabilized by the addition of copper and nickel.   The
gamma form vill convert to the alpha form if not kept at low temperatures.
Manganese is capable of forming a series of bivalent  and tetravalent salts.
The most common salt compounds are permanganates and  strong oxidants.

Manganese occurs in over one hundred minerals.  Manganese is usually found
in metamorphosed deposits such as marbles, slates, quartzites, schists, and
gneisses.  Manganese ore is widely distributed in the U.S. with the richest
deposit found in Franklin, New Jersey and the largest deposit located at
Chamberlain, South Dakota.

The diversity and complexity of manganese formations lends them to several
types of impurities; metallic (iron, lead, zinc), nonmetallic (sulfur,
phosphorous minerals), gangue (silica, alumina, lime), and volatiles
(water, carbon dioxide, organics).  Primary manganese minerals include
pyrolusite, psilomelane, manganite, and hausmannite.

Manganese nodules are found, in  the ocean.  These deep sea nodules are  found
over wide areas of the ocean floor.  Currently, the higher-grade deposits
are found in the North Pacific Ocean.

Manganese alone is of little use.  Manganese  is an essential  ingredient  for
steel making and for that purpose  is commonly used as a  ferro alloy
composed chiefly of manganese and  iron.   In alloyed or  metallic form
manganese can be used as a cleansing agent for steel, cast iron,  and
nonferrous metals.  Manganese serves in  the steel industry as a control  of
hot shortness in finishing processes,  as  a deoxidizer,  and as an  alloying
                                   3-U3

-------
agent  to improve strength, hardness, abrasion, and wear resistance.
Manganese neutralizes sulfur and adds strength to cast iron.

The aluminum industry utilizes manganese in the forms of manganese-aluminum
briquettes, master alloys and powdered electrolytic manganese to harden,
strengthen, and stiffen aluminum metals.

Manganese dioxide is used in the production of dry cell batteries.
Manganese gives colors from bright reddish purple to purple black to
ceramics, brick, and tile.  In chemical applications, manganese is used as
a catalyst, oxidizer and chemical intermediate in the manufacture of both
organic and inorganic compounds.  Manganese promotes absorption of oxygen
in the drying of paints and varnishes.

There  is no production of manganese ore containing 35X or more manganese in
the Unites States.  In 1987, 390,000 short tons of manganese ore and
430,000 short tons of ferromanganese were imported.  The manganese ore was
used by about 20 firms mostly located in eastern and mid western states.
Much of that utilization was directly as ore.

In the Minerals Yearbook, 1985, the Bureau of Mines surveys found 8 plants
owned  by 6 companies producing manganese products from ore.  Two plants
produced ferromanganese alloy, one of those also produced silico manganese
alloy and manganese metal.  One plant produced manganese metal only, and 5
plants produced manganese dioxide only.

Flow charts for manganese processing are shown in Figures 3-46  through
3-49.  The two plants producing ferromanganese use different  techniques.
One uses submerged arc electric furnaces and  the other uses a  fused-salt
electrolysis method similar to  the Vail process for aluminum.   Vastes
expected from the submerged arc process would be slag and baghouse dust
from furnace fume collection.  The plant using the submerged  arc  process
for ferromanganese also produces silicomanganese alloys  by the  same method.
The slag from ferromanganese production is fed as part of  the  charge  to the
                                   3-144

-------
                               Figure 3-46
                           MANGANESE PROCESSING
                             ANACONDA PROCESS
                                    Ore
Oil Emulsion
    or
Soap Solution
Oxidizing
  Agent
Flotation
Tailings
 Rotary
  Kiln
                              Manganese Oxide
                                  Nodules
                                    3-145

-------
                               Figure 3-47
                           MANGANESE PROCESSING
                           DEAN - LEUTE PROCESS
Cuyuna
 Ore
Ammonium
Carbonate
Reduction
  Agent
   Roaster
                         Manganese Containing Ore
                                    _v
  Leaching
  Process
                            Manganese Carbonate
Reduction
 Process
                              Manganese Oxide
->Waste Leachate
      Solution
                                    3-146

-------
                               Figure  3-48

                           MANGANESE PROCESSING
                             DAUGI1ERTY PROCESS
Low Grade
Ground Ore
       Steam-
                           Vater
                 Sulfur Dioxide (g)
       Spray
       Mixer
(Injection System)
                             Manganese Sulfide
                             Manganese Sulfate
                                in Solution
                                                    Filtrate
                                         Filter Calce
                              Manganese Oxide
                                      3-147

-------
                                Figure 3-49
                           MANGANESE PROCESSING
                               WELCH PROCESS
Low Grade
   Ore —
                               Sulfuric Acid
Digestion
                             Manganese Sulfate
                               Electrolytic
                                   Cell
                             Manganese Dioxide
Spent Ore
                 -> Waste Electrolyte
                 -» Electrolytic Slimes
                                    3-U8

-------
silicomanganese furnace.  Silicomanganese production would  also have
baghouse dusts and slag as wastes.  Both the baghouse dust  and slags could
contain leachable toxic metals that could cause them to exhibit the RCRA
characteristic of EP toxicity.  Information on characteristics and
quantities of these wastes was not available at the time of this writing.

The fused salt electrolysis method of making ferromanganese would produce
wastes similar to those from aluminum production.   Specific information was
not available at the time of this writing.

Manganese metal and synthetic manganese dioxide can be produced by
electrolytic processing (Figure 3-49).  In either case, a solution of
manganous sulfate is the electrolyte.  Electrolytic metal is deposited at
the cathode and manganese dioxide at the anode.  Both producers of
manganese metal and four of the five producers of manganese dioxide use
electrolysis.  Wastes could include spent electrolyte which would be acidic
and possibly EP toxic and electrylyte purification which also could be
acidic or toxic.  Characteristics and quantities of these wastes were not
available at the time of this writing.

The fifth manufacturer of synthetic manganese dioxide uses a chemical
approach (Figure 3-47).  In this method the manganese feed material is
dissolved as a sulfate solution.  Manganese carbonate is precipitated and
then decomposed to manganese dioxide.  The wastes from  this process were
not described in the literature reviewed for  this report.

Producers of manganese materials  from imported ore use  several  different
processes and make several types of products.  Readily  available  literature
does not contain much information on  the characteristics of wastes  from
these processes (Table 3-18).  The information available does  indicate  that
some of these wastes could exhibit hazardous  characteristics.   Further
study of the manganese industry,  for  possible regulation under  Subtitle C,
is recommended.
                                   3-149

-------
Ln
O
                                                        Table 3-18

                                               MANGANESE PROCESSING  WASTES
Possible RCRA Characteristic
Process
Submerged Arc Electric Furnace
(Ferromanganese and
silicomanganese)
Fused Salt Electrolysis
Electrolytic Production of
Manganese and MnO-
Chemical Production of MnO_
Waste
1) Slag
2) Baghouse Dust
1) Wastes
1) Waste Electrolyte
2) Electrolyte Purification
Waste
1) Waste
R
N
N
7
N
N
N
C
N
N
9
7
7
7
I
N
N
N
N
N
N
T Comments
? FeMn slag recycled to
? SiMn production
9
7
7
7
     * RCRA  characteristics  are  reactivity,  corrosivity,  ignitability, and EP toxicity as defined in 40 CFR 261
       Subpart C.

     N - Waste not expected  to exhibit  this  characteristic.
     Y - Strong  indication  that  waste would  exhibit  this  characteristic.
     ? - Possibility  that waste  could exhibit  this characteristic.

-------
                                REFERENCES

Lefond, S.J., ed.; Industrial Minerals and Rocks 5th edition; Society of
     Mining Engineers; New York, N.Y.; 1983.

Marks, H.F., ed.; Encyclopedia of Chemical Technology 3rd edition; Uiley-
     Interscience; Nev York, N.Y.; 1978.

U.S. Bureau of Mines; Mineral Commodities Summary 1987; U.S. Bureau of
     Mines; 1987.

U.S. Bureau of Mines; Mineral Facts and Problems 1985; U.S. Bureau of
     Mines; 1985.

U.S. Bureau of Mines; Minerals Year Book 1985; U.S. Bureau of Mines; 1987.
                                    3-151

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                                MOLYBDENUM

Molybdenum is a silvery-white, hard metal with a very high melting
temperature.  The primary use for molybdenum is as an alloying element for
steel.  Secondary uses generally make use of its corrosion resistance and
high temperature properties.  Molybdenum disulfide is a lubricant similar
to graphite and is used alone and as a component of greases.

There are four mines in the U.S. that produce primarily molybdenum ore.
Two are in Colorado, one in Idaho and one in New Mexico.  Nine other mines,
in Arizona, Nevada, New Mexico,  and Utah can produce molybdenum as a
byproduct of copper mining.  Lov prices and large stockpiles have caused
considerable fluctuations in molybdenum production in recent years.  The
U.S. Bureau of Mines records show the following molybdenum production
figures: 1982-84.4, 1983-33.6, 1984-103.7, 1985-108.4 million pounds.  In
1986, production was estimated at 94 million pounds.  This variation is
often due to temporary mine closings, and it is unlikely that all of the
mines mentioned above are producing at any one time.

The only ore mineral of molybdenum is molybdenite, which is naturally
occurring molybdenum disulfide (MoS^).  Molybdenite can be readily
recovered from its ores by froth flotation, which is the process used
universally in the U.S.  At the four primary molybdenum mines, the recovery
process is generally as shown in Figure 3-50.  The ore goes through a
preliminary size reduction then a first stage of froth flotation, which
recovers enough of the molybdenite that the tailings are discarded.  The
molybdenite concentrate contains considerable amounts of impurities, which
are removed by several stages of regrinding and froth flotation.  The
tailings from these stages are recycled and eventually end up  in  the
primary tailings.  The primary tailings stream is the only waste  stream
from this process and is not expected to exhibit any hazardous
characteristics, but metal leaching and acid formation are possible.
                                   3-152

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                       Figure 3-50

                        MOLYBDENUM
                 MOLYBDENITE CONCENTRATION
                     (Climax Practice)
                            Ore
May be repeated
 several times
                           Size
                         Reduction
                            _v
                           Froth
                         Flotation
     Tailings
   to byproduct
recovery and waste
                                        1
                           Size
                         Reduction
                           Froth
                         Flotation
                            _v
                       Final Product
                           MoS,
                          3-153

-------
The recovery of molybdenite from copper-molybdenum deposit's is similar to
that from primary molybdenum deposits.  If the molybdenite content of the
ore is high enough, it will be recovered by froth flotation separately from
the copper minerals, usually before the copper minerals.  The more common
situation is that the molybdenite is at a low enough concentration in the
ore that direct recovery is not economically feasible. In these cases the
molybdenite and copper minerals are recovered in a bulk froth flotation and
separated subsequently.  Some operations recover the molybdenite first and
others the copper first from the bulk froth flotation concentrate.  Froth
flotation tailings are the only significant waste expected from this
recovery and are not expected to shov any unusual characteristics different
than those of copper tailings, including acid formation and metal leaching.

A small amount of molybdenite is upgraded by froth flotation for use as a
lubricant.  This process is a continuation of that described above for the
production of molybdenite concentrates.  Most molybdenite is converted to
technical grade molybdic oxide, vhich is the starting material for a
variety of chemical and metallurgical products.

Technical grade molybdic oxide (HoO.) is made by roasting molybdenite
concentrates in an oxidizing atmosphere at temperatures between 1000°F and
1300°F.  The overall reaction produces molybdic oxide and sulfur dioxide.
The sulfur dioxide is removed from the flue gases along vith flue dusts
vhich could contain volatile metals that vere contaminants in the
concentrates.  These might include lead, zinc, tin, and others.  The  flue
dusts and flue gas desulfurization sludges are the only vastes produced by
this process, and as stated above, the flue dusts may exhibit toxic
characteristics.  Four companies produce technical grade molybdic oxide at
five plants in Arizona, Iova, Pennsylvania, and Utah.

Technical grade molybdic oxide is the most widely used  form  of molybdenum
for alloying in steels.  It may be used as a powder or  formed into
briquettes to reduce dust losses.  The other form of  molybdenum used  for
alloying is ferromolybdenum, an iron alloy.  The molybdenum  content  varies
                                   3-154

-------
widely, but there are only two general processes for producing it.   High
carbon content ferromolybdenum is made by reducing technical grade  molybdic
oxide, calcium molybdate or sodium molybdate with carbon in the presence of
iron in an electric furnace.  The impurities form a slag which is thrown
away.  This slag is not expected to exhibit any hazardous characteristics.

Low carbon ferromolybdenum produced by the thermite process is more common
than the high carbon alloy.  In this process technical grade molybdic
oxide, aluminum, ferrosilicon, iron oxide, limestone, lime, and fluorspar
are mixed and the aluminum ignited.  There is a very rapid reaction which
produces fumes and dust which are drawn away by fans and collected  in a
baghouse.  These fumes are not expected to exhibit hazardous
characteristics.  A metal "button" and a slag are also formed which are
allowed to solidify and are then separated.  The slag, which is not
expected to exhibit any hazardous characteristics is discarded.

Other products are made from technical grade molybdic oxide in smaller
quantities.  These include sublimed molybdic oxide of high purity and
ammonium molybdate.  The production of sublimed molybdic oxide is not
expected to produce significant quantities of waste with hazardous
characteristics. Ammonium molybdate is produced by dissolution of technical
grade molybdic oxide in ammonium hydroxide.  Specific impurities are
removed by stages of treatment that may include selective precipitation,
ion exchange and solvent extraction.  Then the ammonium molybdate is
removed by crystallization.  The exact procedure is proprietary  to each
producer.  There are hazardous materials used in these processes, but  the
amounts and characteristics of any wastes are not available in the
literature reviewed.

The waste streams and possible hazardous characteristics  from  the
production of molybdenum products are summarized in Table  3-19.  There are
several waste streams that could exhibit hazardous characteristics.
Therefore, further study for possible regulation under Subtitle  C  is
recommended.
                                   3-155

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Ul
                                                        Table 3-19

                                                    MOLYBDENUM  WASTES
Process
Molybdenite Recovery
from Ore
Technical Grade
Holybdic Oxide
Production
Ferromolybdenum
Production
High Carbon
Low Carbon

Ammonium Holybdate
Production
Waste
Tailings

Flue Dust




Slag
Slag
Flue Dust
Wastes

Possible RCRA Characteristic*
R C I T Comments
N ? N ?

N N N ?




N N N N
N N N N
N N N N
N ? N N

             *  RCRA characteristics are Reactivity,  Corrosivity,  Ignilability, and EP Toxicity as defined in
               40 CFR 261 Subpart C.

             N  - Waste not expected to exhibit  this  characteristic.
             Y  - Strong indication that waste would  exhibit  this  characteristic.
             ?  - Possibility that waste could exhibit  this characteristic.

-------
                                REFERENCES


Veiss, SME Mineral Processing Handbook 1985 Published by Society of Mining
    Engineers of AIME.

U.S. Bureau of Mines, Mineral Commodity Summaries; 1987.

U.S. Bureau of Mines, Minerals Yearbook; 1985 Volume 1.

U.S. Bureau of Mines, Mineral Facts and Problems; 1985.
                                   3-157

-------
                           PLATINUM GROUP METALS

The platinum group metals (PGM) consist of ruthenium,  rhodium,  palladium,
osmium, iridium, and platinum.  The six metals can be  classified into three
groups of tvo, with each pair corresponding to a different family on the
periodic table.  Each metal pair exhibits similar physical and
metallurgical properties.

Ruthenium and osmium are the hardest pair and have the strongest rigidity
and abrasion resistance of the PGMs.  Because of this, osmium alloys are
used videly as pen tips and phonograph needles.  Ruthenium is used mainly
as an electrical contact and in the chemical industry  as a titanium anode
coating material.

Rhodium and iridium are the least abrasion resistant of the PGMs and have
limited ductility at normal temperatures.  Both metals are mainly used as
alloying elements for platinum.  Rhodium is also used  as automotive
catalyst for NO  reduction.
               X

Platinum and palladium are the softest and most malleable of the group and
are both corrosion resistant.  They are often alloyed.with other PGMs and
are the most videly used.  Platinum's major use is as  a catalyst in the
automotive,  petroleum, and chemical industries.  Palladium is used most
videly in the electrical, medical, and dental industries.  It is also used
in automotive catalytic converters.

The United States imports approximately 98% of  its PGMs.  Domestic
production has been dropping for several years  due to decreases  in  the
mining and processing of copper, from vhich the PGMs are  recovered.
Approximately one ounce of PGM is recovered for every 35  short  tons of
copper produced in the U.S.  Currently, domestic PGM production  occurs as  a
by-product at two copper refining plants, in Utah and Texas.
                                   3-158

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In copper refineries in the U.S., PGM's are typically recovered from slimes
that collect in electrolytic refining cells (Figure 3-51).   These slimes
are the insoluble materials from the impure copper anodes that are
dissolved as part of the refining process.  The slimes are removed from the
cells periodically, and processed for their metal content.   The initial
treatment is to remove any remaining copper by leaching either vithout or
after roasting.  The decopperized slimes are then melted in a reverberatory
furnace vith a soda-silica flux.  The flux helps form a siliceous slag
vhich is removed from the furnace.  Air is then blown through the molten
metal and a lime flux is added.  The air oxidizes any lead in the molten
metal and the lead oxide forms a slag vith the lime vhich is removed, from
the furnace.  The siliceous slag and the lead slag are recycled or sent to
a lead smelter.  Fused soda ash is added to the furnace to form a soda
slag.  This slag is removed and sent to processing to recover selenium and
tellurium.  The remaining metal is a dore alloy containing gold, silver and
platinum group metals and is processed to separate them.

There are three major sources of PGM ores in the U.S. vhich could be
exploited if the price of platinum vere to rise high enough.  Since the
U.S. imports most of its platinum from the Republic of South Africa, supply
cutoffs (and price increases) could possibly occur due to the social
instability of that country.  The other major supplier of platinum  is  the
Soviet Union.  The three potential mining locations are at Stillvater,
Montana; Duluth, Minnesota; and Crillion-La Perouse, Alaska.  The
Stillwater site is the largest, containing approximately 75% of  the
identified PGM reserve base in  the U.S.

Platinum and palladium mining began at the Stillvater, Montana  (near Nye,
MT) site in March 1987.  The platinum and palladium are  recovered by bulk
froth flotation of sulfide minerals.  Vastes expected are listed  in Table
3-20.  Concentrates are shipped  to Antverp, Belgium,  for metal  recovery.
There are no current plans for mining of  the PGM deposits at  the  Duluth or
Crillion-La Perouse locations.
                                   3-159

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                         Figure   3-51




PLATINUM GROUP METAL  (PGM)  RECOVERY FROM COPPER REFINING SLIMES
Sc/ubber mud
Gas
t
Sciubbet *nd
Cottiell
JSolution iCtude
To selenium plant
Gas
t
Sciubber and
Conrell
Sotuticn I
To selenium plant
H,S04 —
Fume
* HjO—
NaOH_
H,0
Fluxes —
Gases
To mode <
Raw slimes
1
Heneshort lurnace
* >
Otied slime
Acid digesters
1
Chain roaster
~"~l >

Leach tanks
>
t
Holding tanks
^ >
r
Caustic (each
tanks
T ^
SO}
Scrap copper
1
Leach liquor _

I Leach liquor to
CuSOi plant or
Cement silver 1 |lbeia,0, ulis
H2S04 	 ^
C'wt'C > Meutnli»tion
solution tanks
Caustic slimes H;0 	 > >rTe-Pb mud
One furnace
rv,i
furnace Slag
Partin
^
i nodes
1
I plant
f
Soda slag Slag leaching Residue Anode
X . tank > plant
HjS04 	 ^ vSolutkjn
Neutraluation
tank
(Solution 1 Neutralised mud
| t
To Se plant To T« plant
                     Platinum group metals
                              3-160

-------
u»
I
o\
                                                        TABLE 3-20



                                           PLATINUM GROUP METAL RECOVERY WASTES
Process
Ore Processing
1. Froth Flotation
2. Filtration
3. Thickening
Production from Copper
Refining Slimes

Waste
Tailing Waste
Filtrate Waste
Waste Waters
Spent Acids
(from parting/refining)
Possible RCRA
R C I
N N N
N ? N
N ? N
N ?
Characteristics*
T
7
7
7
N
Comments
7
      *  RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity  as  defined  in 40CFR 261

        Subpart  C.


      N  -  Waste  not expected to exhibit this characteristic.

      Y  -  Strong indication that waste would exhibit this characteristic.

      ?  -  Possibility that waste could exhibit this characteristic.

-------
Many materials containing PGM also contain gold and silver so the refining
processes  for these materials also recover the other precious metals.
There are  two processes in use today, selective precipitation and solvent
extraction.  Solvent extraction is a more recent development that is
replacing  selective precipitation due to reduced time, capital and
operating  costs.

In  the selective precipitation process, the material to be refined is
dissolved  in aqua regia (a mixture of hydrochloric and nitric acids).  Gold
is  then precipitated from solution followed by platinum and palladium.  The
insoluble  residue is treated to recover silver land the remaining PGM
rhodium, iridium, ruthenium, and osmium.  These metals are separated in an
elaborate  series of stages to yield pure metals.  The primary wastes 'from
this process would be spent acids, which might contain residual metals.

In  the solvent extraction process the feed material is preleached to remove
any base metals.  It is then leached with hydrochloric acid and chlorine to
dissolve the PGM.  A series of solvent extractions remove and recover each
of  the metals separately.  Again, the wastes expected would be spent acids.

The mining, beneficiation, and processing of PGMs can occur in conjunction
with the recovery of other metals (such as copper and nickel) or  it  can be
a site's sole activity.  There is now a PGM mine in operation, however, no
information is yet available about the nature of the wastes from  it.  The
information available concerning PGM refining suggests that it may produce
wastes with hazardous characteristics.  Therefore, further study  of  this
industry for potential regulation under Subtitle C is recommended.
                                   3-162

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                                REFERENCES

Bureau of Mines, 1987.  Mineral Commodities Summary,  1987.

Cabir, Louis J., ed.  Platinum Group Elements:   Mineralogy,  Geology,
     Recovery.  Harpell's Press Cooperative,  Quebec,  1981.

Engineering and Mining Journal, "Stillwater gets and  early start on
     palldium-platinum mining", Volume 188, Number 5, May 1987.

Lanam, Richard D.,  and Zysk, Edward D.,  Platinum Metal Groups, Encyclopedia
     of Chemical Technology, Viley-Interscience, New York,  New York, 1978.

Loebenstein, J.R.  "Platinum Group Metals", Mineral Facts and Problems,
     1985 edition.   U.S. Bureau of Mines.
                                   3-163

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                             RARE EARTH METALS

The rare earth metals include sixteen elements:   yttrium  (atomic  number
39), lanthanum (57), cerium (58), praseodymium (59),  neodymium (60),
promethium (61),  samarium (62), europium (63), gadolinium (64),  terbium
(65), dysprosium (66), holmium (67),  erbium (68),  thulium (69), ytterbium
(70), and lutetium (71).  The elements with atomic weights 57  to  71 are
collectively called the lanthanides since they all have properties similar
to lanthanum.  Scandium (21) is sometimes included as a rare earth metal
since it is chemically similar to yttrium and 'the lanthanides.

The major use of rare earth metals are as catalysts in petroleum  refining.
They also have many metallurgical applications as pyrophoric alloys.   The
third major application is the use of lanthanide oxides as a constituent of
high quality optical glass.

The two major minerals used as sources of rare earth metals are monazite
(Ce-La-Nd-Pr phosphate) and bastnaesite (Ce-La-Nd-Pr fluorcarbonate).
Monazite is mined in Australia, India, the United States, and  other areas
to a lesser degree.  Bastnaesite is primarily mined in the United States
and China.  Several other ores are mined for  the rare earths as veil,
including xenotine, apatite, yttrofluorite, cerite, and gadolinite.  Total
U.S. production of rare earth metals was approximately 14,000 short tons  in
1986.  Virtually all of the rare earth metals consumed in the U.S. are
mined and processed domestically; reliance on imports is  minimal.

Rare earth mineral ores are mined domestically by  two companies at mine
locations in California (bastnaesite ore) and in Florida  (monazite ore).
The bastnaesite mining  is principally  for  the recovery of the rare earths.
The monazite mining occurrs in conjunction with  the  processing of  heavy
mineral sands for titanium and zirconium recovery.   These ores are
processed by four companies with plants  in Arizona,  California, Colorado,
Pennsylvania, Tennessee, and Texas.  The processing  of monazite ore in the
                                   3-164

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U.S. is accomplished by sulfuric acid digestion,  and  bastnaesite  ore  by
hydrochloric acid digestion.

HONAZITE ORE PROCESSING

Rare earth metals are recovered as oxides from monazite ore by an acid
                             f
digestion process as shown in Figure 3-52.   The ore undergoes grinding,
spiraling, or other similar operations for  the initial coarse purification
of the ore.  Magnetic separation removes the magnetic ore constituents
which can be processed separately or discarded as waste.   The refined ore
is then digested with sulfuric acid at 200°-220°C.   Rare earth sulfates and
thorium sulfates are then dissolved and removed from the waste monazite
solids by filtration.  Rare earth elements  are then precipitated as
oxalates or sulfates.  These precipitates undergo caustic digestion (or
roasting) to form rare earth oxides which are finally recovered by
filtration.  The resulting filtrate is discarded as a waste.

BASTNAESITE ORE PROCESSING

Bastnaesite mining near Mountain Pass in southeastern California is the
major source of rare earth metals in the U.S.  The recovery process of the
rare earths from this ore is shown in Figure 3-53.   The ore is initially
crushed, ground, classified, and concentrated to increase the rare earth
concentrations from 15% to 60%.  Tailings produced during these operations
are discarded as waste.  The concentrated bastnaesite undergoes an acid
digestion to produce several rare earth chlorides.   Hydrochloric acid  is
used to digest the bastacestite.  The resulting slurry is filtered, and  the
filter cake is further digested with sodium hydroxide  to produce rare  earth
hydroxides.  This rare earth hydroxide cake is chlorinated, converting the
hydroxides to chlorides.  Final filtration and evaporation  yields  the  solid
rare earth chloride products.  The wastes produced include  a  sodium
fluoride  filtrate, which is  recovered for further  processing, and  filter
cake which is discarded.
                                   3-165

-------
                          Figure 3-52

RARE EARTH RECOVERY FROM HONA2ITE DY THE SULFURIC ACID PROCESS
                         Monzanitc Ore

                              1
                           Spirals
                           Magnetic
                          Serration
    •Waste Tailings
     Magnetic
   "^Fractions
                         (_. Grinding  (
                           Digestion
                          200°C-220°C
               Cold Water-
                                     Slurry
                        Dissolution of
                        Rare Earth And
                       Thorium Sulfates
                          Filtration
     Waste
 -»Monazi te Solids
                                 Filtrate
                        Double Sulphate
                         Precipitation
      NaOH and Water
                          FiIt ration
Cnke
                                 Filtrate
                                                     I
 Caustic
Digestion
                        Recovery of
                    Thorium and minor
                  Rare Earth Fractions
                 Slurry
       I-'ilt ration
           -» Waste
           Filtrate
                                              Rare Earth
                                            Hydroxide Cake
                              3-166

-------
                               Figure 3-53
         PRODUCTION OF RARE EARTH CHLORIDES FROM BASTNABSITE ORE
                             Bastnaesite Ore
 Cake  <-
Reject
                                Crushing
                                Grinding
                                                       •Waste Tailings
                               Classifier
                      ->Vaste Tailings
                                   u   r-HCl
                             Acid Digestion
                                  NaOH
                                        slurry
                               Filtration
                 Cake
                                             Rare Earth
                                   Filtrate   Fluoride
         Alkali
       Digestion
                             Neutralization
                 CaRe.
                                                                   Slurry
       Filtration
                                             nare Earth
                                             Hydroxide
Filtration
                                  I
             iltrate
                                      Filtrate
Sodium Fluoride
    Recovery
                               Evaporation
                                  T
                               Rare Earth
                            Chloride Product
                                   3-167

-------
The rare earth hydroxides and chlorides which arr recovered  from  monarite
and bastnaesite ore, respectively,  have no markets or  commercial  uses.
They must undergo further processing to produce and recover  individual  rare
earth metal compounds for a variety of applications.   Several  processes are
used to produce rare earth fluorides, nitrates, carbonates,  oxides,  and
pure metals.  Processes used include fractional crystallization,  fractional
precipitation, solvent extraction,  ion exchange,  and  reduction.

Using fractional crystallization, one or more rare earths in a mixture  are
precipitated by changing the salt concentrations in solution through
evaporation or temperature control.  Fractional precipitation involves
adding a precipitating agent to selectively remove a metal from solution.
A wide variety of processes have been developed to recover specific rare
earths by these two techniques, including:

    •  Separation of lanthanum, praseodymium, and neodymium with ammonium
       nitrates;
    •  Separation of yttrium earths by bromate crystallization;
    o  Cerium salt purification using ammonium nitrate;
    «  Separation of lanthanum by magnesia basicity precipitation; and
    •  Separation of yttrium group by sodium sulfate precipitation.

In general, crystallization and precipitation processes produce waste  salts
and salt solutions requiring proper  treatment- or disposal.  If organic
precipitation is used, then organic-containing vaste fractions may be
produced as veil.

Liquid-liquid solvent extractions are often performed  to separate a mixture
of rare earths from each other.  An aqueous solution containing  rare earth
salts is flowed countercurrent to an  immiscible  organic stream,  i.e.,
tributyl phosphate, which selectively extracts one rare earth  from  the
others.  Several stages of extractions are needed  to separate  each  rare
earth metal.  Each organic stream  is  then scrubbed with an  aqueous  stream
                                   3-168

-------
(acid, basic or neutral) to transfer the rare earth element  into an aqueous
phase.  Figure 3-54 shows such a process for the individual  recovery of
lanthanum, praseodymium, neodymium,  and samarium from a nitrate solution
containing the four together.   Since all of the products are aqueous
solutions, the solvents used all leave the process as wastes.   These
solvents may be discarded as wasted  or recycled.

Ion exchange is used to produce highly pure rare earths in relatively small
quantities.  Since ion exchange processes are batch processes;  they are not
suitable for high volume production; however, few other process can produce
rare earths of such high purity, which are needed for many applications.

Since the rare earths form trivalent cations (3+), a cation exchange resin
is used.  For separating a mixture of lanthanides, the resin is first
flushed with a solution such as cupric sulfate to prepare the resin for ion
exchange (see Figure 3-55).  A solution containing the lanthanides is  then
passed over the ion exchange resin.   The lanthanides displace the cation,
in this case cupric, on the resin surface.  This step produces an aqueous
waste containing the cation which was exchanged, and small amounts of  rare
earths.  At this stage, the lanthanides have been deported on the resin as
a mixture.  To separate individual rare earth elements, an element
containing a complexing agent, such as ammonium ethylenediamine tetra
acetic acid (NH,+EDTA), is passed over the resin.  The EDTA has a high
affinity for rare earths, and the lanthanides are complexed with  the EDTA
and displaced by NH,  on the resin.   Each lanthanide has a different
affinity for EDTA, and  individual lanthanides can be separated and
recovered as a result of these varying affinities.  Relative to  the amount
of product generated, large quantities of waste solutions are generated
during  the process.  The waste solutions may be acidic, basic, or  neutral,
and will contain the metals displaced  from  the  resin during  ion  exchange,
as well as the complexing agents used.

High purity rare earth  metals can be produced by  the metallothermic
reduction of rare earth halides.  This process  is  used  when  99.992 purity
                                    3-169

-------
                             Figure 3-54
                RARE EARTH SEPARATION BY SOLVENT EXTRACTION
                        Rare Earth Nitrate Solution
                             (La,  Pr,  Nd,  Sm)
Nitric Acid Scrub'
                                       \p—Tri-butyl  phosphate solution
                                Extraction
                                   and
                                 Scrubbing
           Solvent (Sm,  Nd,  UNO.,)
Water—•

Vaste
-------
                          Figure 3-55
               LANTHANIDE SEPARATION BY ION EXCHANGE
                            Rare Earth
                        Lanthanide Solution
  Resin
Flushing
Solution
             Flushing
               Wash
       Eluant  with
      Complexing Agent
                                Ion
                             Exchange
                               Resin
Waste
Eluant
                            Rare Earth
                         Product Solutions
                              3-171

-------
is required.  After converting the rare earths into fluorides,  they are
reduced to  the metallic state through contact with calcium or barium at
high temperatures.

A large variety of potentially hazardous wastes are produced during the
mining, beneficiation, and processing of rare earth metals Table (3-21).
The acid digestions used to treat raw ores may produce corrosive wastes,
while refining processes, such as solvent extraction produce vaste solvents
and the aqueous raffinates often contain quantities of residual product and
byproducts which may have hazardous characteristics.  Further investigation
of the quantities and characteristics of these wastes is recommended for
potential regulation under Subtitle C.
                                   3-172

-------
                                                  Table 3-21

                                      RARE  EARTH METAL PROCESSING WASTES
Possible RCRA
Process Waste
Monzanite Ore fUSO, Process Waste tailings
Magnetic fractions
Waste Honazite Solids
Waste Filtrate
Bastnaesite Ore HCL Process Waste tailings
<-> Cake reject
j— *
w Solvent Extraction Waste solvent
Ion Exchange Flushing Waste
Waste Eluant
R
N
N
N
N
N
N
N
N
N
C
N
N
N
7
N
7
7
7
7
I
N
N
N
N
N
N
7
N
N
Characteristics*
T Comments
N
N
7
7
N
N
7
7
7
* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity  as  defined  in 40CFR 261
  Subpart C.

N - Waste not expected to exhibit this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

-------
                                REFERENCES

Bureau of Mines, 1987.  Mineral Commodities Summary,  1987.

Callow, R.J.  The Rare Earth Industry.  Pergamon Press,  N.Y.,  1966.

Spedding, F.H., and A.M. Daane, ed.  The Rare Earths.   John Uiley and Sons,
     Inc.  N.Y., 1961.

Spedding, F.H.  Rare Earth Elements.  Encyclopedia of  Chemical Technology.
     Wiley Interscience, N.Y., 1978.

Shannon,  S.S.  Rare Earths and Thorium.  Industrial Minerals and Rocks,
     1983.
                                   3-174

-------
                                  RHENIUM

Rhenium is a metal vith the third highest melting point and fourth highest
density of any element.  Approximately 90 percent of all rhenium is used in
platinum-rhenium catalysts in the production of unleaded and lov-lead
gasoline.  Because of its superior properties at high temperatures, it is
also used in thermocouples, heating elements, filaments, and electrical
contacts.

There are no ores which are mined for rhenium.1  The majority of rhenium is
recovered from molybdenite concentrates from porphyry copper ores.
Porphyry copper ores are mined in Utah, Arizona, Nevada, and Nev Mexico.
Eight companies produced rhenium from these ores in 1986.

During the processing of porphyry copper ores, molybdenite is concentrated
in order to recover molybdenum.  As a byproduct, the molybdenite
concentrate is treated for rhenium recovery, as shown in Figure 3-56.
Roasting the molybdenite generates volatile oxides of rhenium, molybdenum,
and sulfur.  These oxide fumes are collected by scrubbing with a caustic
solution, vhich neutralizes the sulfur oxides.  Anion exchange (or solvent
extraction) is then used to separate and recover rhenium or perrhenate
(ReO,), vhich is reduced to ReS2 under acidic conditions.  Oxidation and
evaporation then produce a rhenium salt which can either be sold
commercially or be reduced to metallic rhenium by reduction with hydrogen.
The wastes generated include  the roasting slag, anion exchange waste
solutions, and acidic wastes  generated during reduction with  H-S.  If
solvent extraction is used, waste solvent will be generated in place  of  the
anion exchange wastes.

The above-mentioned wastes may potentially  have hazardous  characteristics
(Table 3-22).  Therefore,  further investigation  is  recommended  for
potential regulation under Subtitle C.
                                    3-175

-------
                         Figure 3-56
          Rhenium Recovery From Molybdenite Concentrate
          Water
          NaOH-
           HC1
           H2S  gas
           H°
           H2
                     Molybdenite Concentrate
                       (2,000 ppm Rhenium)

                                i	
                            Roasting
                                  Volatile Oxides
Vet Scrubbing
                         Anion Exchange*
                      Waste
                                   ReO,
   Mixing/
 Separation
-^Wastevater
                                   ReS.
   Oxidize
                                   NH.ReO,
                                     4   A
                            Evaporation
                                   Dry Rhenium Salt
   Reduction
                           Rhenium Metal
                                 3-176
* solvent extraction mav he «nhcr i

-------
                                                  Table 3-22

                                                RHENIUM WASTES
         Process
       Waste
                                                                 Possible RCRA*
                                                                 Characteristics
                           Comments
Roasting

Anion Exchange

Solvent Extraction

Mixing/Separation
Slag

Waste Solution

Extraction Waste

Wastewater
N    N    N    ?

N    ?    N    N

N    N    ?    N

N    ?    N    N
* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as  defined  in 40CFR 261
Subpart C.

N - Waste not expected to exhibit  this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibly that waste could exhibit this charcteristic.

-------
                                REFERENCES




Bureau of Mines, Mineral Commodities Summary, 1987.




Marks, H.U., Encyclopedia of Chemical Technology, 1982,
                                   3-178

-------
                                 RUBIDIUM

Rubidium is a soft, silver-white,  ductile,  alkali  metal.   Rubidium has both
chemical and physical properties similar to potassium and cesium.   It is
one of the most electro-positive and alkaline elements,  second only to
cesium.  Rubidium is the fourth lightest metal.   In the  presence of air,
rubidium reacts violently with water and burns with a violet flame.  Uhen
oxidized, rubidium vill form a mix of four  different oxides:  yellow
monoxide, dark brown peroxide, black trioxide, and dark  orange superoxide.
Rubidium alloys readily with other alkali metals,  alkaline-earth metals,
and other metals.  The metal will form double halide salts with cadmium,
antimony, bismuth, copper, and other metals.   The alkaline alloys and
double halide salts are water insoluble and nonhygroscopic.  Rubidium
compounds such as acetate, bromide, hydroxide, and sulfate are water
soluble and hygroscopic.  In general, rubidium and cesium can be used
interchangeably.

Rubidium is the sixteenth most abundant element in the earth's crust.   It
is widely dispersed and commonly found in association with potassium
minerals and salt brines.  Lepidolite, a lithium mica, contains
approximately 2 to 4 percent rubidium oxide.   Pollucite, a cesium-aluminum
silicate, contains 1.5 percent rubidium peroxide.

There is little commercial use of rubidium.  Rubidium is used on a  limited
basis in the chemical, medical, and electronic industries.  The Bureau  of
Mines estimated in 1985  the U.S. capacity  for producing  rubidium was  above
6000 pounds per year and  forecast  that demand would not  exceed  that  figure
though the year 2000.

Domestic production in 1986 of rubidium was entirely dependent  on  the
importation of lepidolite ores from Canada.  The  traditional  methods  to
extract  rubidium  from ores (Figure 3-57) involve  the recovery of mixed
alkali alums from  the ores.  This  is achieved by  prolonged  heating  of the
                                   3-179

-------
Rubidium-bearing ores
Sulfuric acid
Neutralizing agent
Barium hydroxide
                               Figure 3-57

                                 RUBIDIUM
                             ALUMS.  EXTRACTION
  calciner
                               Calcined Ore
  Sulfuric
    Leach
                                    1
                                alkali alum
                                 solution
                                Fractional
                             Recrystallization
                               Rubidium alum
Neutralization
                            Rubidium hydroxide
                                in solution
                                    1
                               Pure Rubidium
                                   Oxide
  Residue
-> Spent ore
                     unwanted alkali alums
   precipitated  Aluminum
^
*f
Purification
\
i

	 ?
                     precipitated sulfate
                     (Ba SOA)
                                       3-180

-------
ores with sulfuri acid.  The resulting alum solution is filtered from the
residue and washed with water.  The alkali alums are separated by
fractional recrystallizations, and the rubidium alum is neutralized,
forming rubidium hydroxide in solution.  Barium hydroxide is added to the
solution to remove the sulfate by precipitating barium sulfate.

The alternate chlorostannate method (Figure 3-58) requires the removal of a
large percentage of the potassium from the ore.  The dissolved carbonates
are converted to chlorides, including cesium chlorostannate, which is less
soluble than rubidium chlorostannate, and is precipitated out.  Rubidium
chlorostannate is separated from the chlorides by pyrolysis, electrolysis,
or chemical methods.   Rubidium may also be removed from alkali metal
solutions by solvent  extraction and ion exchange (Figure 3-59).

The reduction of pollucite or lepidolite ores with an active metal and
vacuum distillation will yield pure rubidium metal (Figure 3-60).

Since domestic rubidium is extracted from lepidolite imported from Canada,
no domestic mining waste can be identified.  Recovery of rubidium from ores
involves leaching with sulfuric acid, separation by stannic chloride, and
electrolysis.  These processes would result in the following wastes:  waste
acid, waste slimes, sludges and residues, and spent ore (Table 3-23).
Further investigation is recommended for possible regulation under
Subtitle C.
                                    3-181

-------
Potassium Ores
Stannic Chloride
Stannic Chloride
                              Figure -3-58

                                 RUBIDIUM
                      STANNIC CHLORIDE PRECIPITATION
   Separator
                                    I
-^Potassium
                           Dissolved Carbonates
    Cesium
Precipitation
  Cesium chlorostannate
  (PPt)
                           Cesium-free Chloride
                                 Solution
                                    i
                    -> spent chloride solution
                       rubidium chlorostannate (ppt)
                                 Purified
                             Rubidium Chloride
                                      3-182

-------
    Figure 3-59

     RUBIDIUM
FROM ALKALI METALS
        _V
Solvent Extraction
   ion Exchange
     Rubidium
• spent  metals

 spent  solvent



 spent  solution
           3-183

-------
Pollucite or
Lepidolite ores
                                Figure 3-60

                                  RUBIDIUM
                                  REDUCTION
                                Active Metal
                                      I
Reduction
                 Soent Ore
                                                   Spent Metal
                             Pure  Rubidium Metal
                                        3-184

-------
                                                        Table 3-23


                                                     RUDIBIUM WASTES
CO
en
                                                                        Possible  RCRA
                                                                       Characteristic*
Process
Alum Extraction




Stannic Chloride
Precipitation



Solvent Extraction


Reduction
* RCRA characteristics
Subpart C.
N - Uaste not expected
Y - Strong indication
Uaste
1) Calciner Residues
2) Spent Ore
3) Alkali Alums
4) Precipitated Aluminum
5) Precipitated Barium Sulfate
1) Cesium Chlorostannate (ppt)
2) Spent Chloride Solution
3) Pyrolytic Residue
4) Electrolytic Slimes
5) Chemical Residues
1) Spent Metals
2) Spent Solvent
3) Spent Ion-exchange Solution
1) Slag
are Reactivity, Corrosivity, Igni

to exhibit this characteristic.
R C
N
N
N
N
N
N
N
N
N
7
N
N
7
N
lability


that waste would exhibit this characterist
I
N
N
7
N
N
N
N
N
N
7
N
N
7
N
and


ic.

N
N
N
N
N
N
N
N
N
N
N
7
N
N
EP



T Comments
7
7
7
N
N
7
?
7
7
7
7
N
7
7
Toxicity as defined in 40CFR 261



? - Possibly tha-t waste could exhibit this charcter istic.

-------
                                REFERENCES




Marks, H.F., Encyclopedia of Chemicals Technology, 1978.




U.S.tBureau of Mines, Mineral Commodity Summaries, 1987.
                                   3-186

-------
                                 SELENIUM

Selenium is a nonmetal with semimetallic properties.   Its electrical
conductivity is normally low,  but when it is irradiated by light,  its
conductivity increases up to 200 times.   The change in conductivity is
proportional to the light intensity,  and because of this selenium is used
to make light sensing devices.   Its major uses are in electronic and
photocopier machines, in glass  manufacturing,  and in chemical pigments.

Selenium is found in 75 different mineral spec.ies, although no selenium
ores exist.  As there are no ores which could be mined only for selenium,
it is obtained as a secondary product during the recovery of other metals,
primarily as a byproduct of copper refining.  Electrolytic copper refinery
slimes contain 1.5 to 21 wt percent selenium,  depending on the quality of
the copper ore used.

The two primary methods of recovery of selenium from copper slimes are
smelting with soda ash (Na.CO.) and roasting with soda ash.  The soda ash
smelting process is shown in Figure 3-61.  After the copper has been
removed from the slime, the slime is mixed with soda ash and silica and
smelted in a furnace.  Slag containing silica, iron, and several other
metal impurities is' produced as a waste.  The molten charge containing
selenium is aerated to oxidize and volatilize the selenium, and the
remaining solids are removed for precious metal recovery.  The soda ash  is
leached with water and filtered  to separate unwanted solid impurities,
which are discarded as waste.  The selenium-containing  filtrate is
neutralized to precipitate out tellurium, and is  then acidified to
precipitate selenium.  The selenium sludge  is then boiled, washed,  dried,
and pulverized to yield the selenium product.  Washing  produces a
relatively clean wastewater stream.

The second major selenium recovery process, soda  roasting,  is  shown in
Figure 3-62.  Decopperized slime is roasted with  soda ash  to  produce  sodium
                                   3-187

-------
                                                     Figure  3-61
00
oo
SELfcNHM KECDVEKI FRCH COPPER SLIMS BT SCCA SHEUDG
soda ash silica air niter
v \r \r \r
Copper Slime
containing
seleniun



L
. Copcer
" Removal
1
„ v
Copper
soda ash
I
^.1 ~<,^'~» 1
^1 nuxing i
solids to precious
metal recovery
sulfuric acid
->j Acidification j —

,, Smelting

Slag
vater
J.



steam
i
-J Q^ . -I . 1


^ Oxidation and
" Volatilization
Slag

"\l Fil frHnff 1
^l rli. idling I
Filter cake
vaste
vater


vaste vater
_^ Flue Particulate 	 ^,
Collection "

sulfuric acid
w


ppt to teleniun
recovery

- O^^Vi " 1

i
Pulverizing
                                                                                          Selenium

-------
                          Figure 3-62

      SELENIUM RECOVERY FROM COPPER SLIMES BY SODA ROASTING
Soda Ash-
Water
Acid-
SO,
Water
                          Copper Slime
                       Containing Selenium
                                v
                             Copper
                             Removal
   Roasting
   Leaching
Neutralization
                                v
 Precipitation
                               _v
    Washing
                   —^Copper
-»Slag
   Waste Solids
—5>ppt  to tellurium
   recovery
   Wastevater
—»Wastevater
                     Drying and Pulverizing
                                1
                            Selenium
                                3-189

-------
The selenium is then leached with vater, neutralized to precipitate
tellurium and then with S02 to precipitate selenium.  Uastewater produced
during the precipitation and final washing operations may be acidic.

The selenium obtained by either the soda smelting or soda roasting process
is purified as shown in Figure 3-63.  The crude selenium is dissolved in
sodium sulfite, and the resulting solution is filtered to remove unwanted
solids in the waste filter cake.  The filtrate is acidified with sulfuric
acid to precipitate the selenium.   An acidic wastewater is produced during
this precipitation process.  The selenium precipitate is distilled to drive
off impurities, producing a high purity selenium for commercial/industrial
use.

The processes identified for the recovery and purification of selenium
include standard unit operations used in the industry.  Besides the use of
acids,  no hazardous substances were identified as being used in the
processing.   Still, it is possible that the wastewater or slags produced
may have hazardous characteristics (Table 3-24).  Therefore, further
investigation for possible regulation under Subtitle C is recommended.
                                   3-190

-------
Sodium Sulfite
Sulfuric acid
                              Figure 3-63




                      PURIFICATION OF CRUDE SELENIUM










                              Crude Selenium
                                    1
Dissolution
                                Filtration
Precipitation
                                Distillation
                                    T
                             Purified Selenium
                     Waste filter cake
Vastevater
                     Waste impurities
                                     3-191

-------
   Table 3-24



SELENIUM VASTES
Possible RCRA Characteristic*
Process
Soda Smelting



Soda Roasting


Selenium Purification


* RCRA characteristics
40CFR 261 Subpart C.
N - Uaste not expected
Y - Strong indication
? - Possibly that wast
Uaste
1) Smelting Slag
2) Oxidation Slag
3) Filter Cake
4) Uastewater
1) Roasting Slags
2) Leaching Solids
3) Uastewater
1) Filter Cake
2) Uastewater
3) Distillation Impurities
are Reactivity, Corrosivity,

R C
N
N
N
N
N
N
N
N
N
N
Igni tabili ty

to exhibit this characteristic.
that waste would exhibit this characterist
e could exhibit this charcteristic.
I
t
7
7
7
7
7
7
N
7
N
and

ic.
T Comments
N ?
N ?
N ?
N N
N ?
N ?
N N
N N
N N
N N
EP Toxicity as defined in



-------
                                REFERENCES




Bureau of Mines,  Mineral Commodities Summaries,  1987.




Marks, H.W.,  Encyclopedia of Chemical Technology,  1978.
                                   3-193

-------
                         SILICON AND FERROSILICON

Silicon is a hard, brittle,  silver-gray metalloid  that  is  never  found  free
in nature.  It is always found in compounds  with oxygen or other elements
as oxides or silicates.   Silicon comprises approximately 26 percent  of the
earth's crust making it  the  second most abundant element after oxygen.
Almost all of the crust  is made of silicate  minerals.   Silica, silicon
dioxide, is used as an industrial material in itself  and is discussed
elsewhere.  Most silicon is  used as an alloying element in the steel and
aluminum industries, both as silicon metal and as  ferrosilicon alloy.
Another major use of silicon is in the manufacture of silicones  and  silanes
in the chemical industry.  A use that is small in  volume (approximately 1
percent of total consumption) but of great economic significance is  in the
manufacture of solid-state electronic devices. Total domestic production
of all forms was estimated at 360 thousand short  tons in 1986.
Ferrosilicon was produced by 8 companies in 13 plants,  primarily for  the
steel industry.  Silicon metal was produced by 6  companies in 7  plants,
primarily for the aluminum and chemical industries.

In the U.S., all primary production of silicon metal  and ferrosilicon is by
reduction in submerged arc electric furnaces.  The feed silica materials
require little processing other than washing, crushing, and sizing.   The
silica is mixed with a reducing agent, either coal, coke,  or charcoal and
fed into the furnace.

Iron and/or steel scrap are added in proper proportions if ferrosilicon  is
the product.  The furnaces typically process 150 to 200 short tons per day.
The furnace is tapped periodically and the molten silicon  or ferrosilicon
is drawn out and cast into ingots.  The ingots are allowed to cool,  then
are crushed to produce the final product.  These furnaces  are generally
equipped with fume collection systems and baghouses to  reduce air pollution
by capturing emissions from the furnace.  The baghouse dust could contain
leachable toxic metals,  particularly if scrap steel is used to  make
                                   3-194

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ferrosilicon.  The references used for this report do not discuss any other
waste streams from silicon and ferrosilicon production.

Semiconductor silicon, silicone chemicals,  and silicon carbide are all made
from silicon metal by secondary processing  and,  therefore, the production
of these materials will not be discussed in this report.   The only waste
identified for silicon and ferrosilicon production is the baghouse dust
from the electric arc furnaces (Table 3-25).  This dust  may exhibit the
characteristic of EP toxicity.  Therefore,  further study for potential
regulation under Subtitle C is recommended.
                                   3-195

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                                                  TABLE 3-25

                                           SILICON AND FERROSILICON
                                                                Possible RCRA Characteristic*
Process                           Waste                         R    C    I    T    Comments


Submerged Arc Furnace Reduction   Baghouse Dust                 N    N    N    ?
* RCRA characteristics are Reactivity, Corrosivity, Ignitability, and EP Toxicity as defined in 40 CFR 261
    Subpart C.

N - Waste not expected to exhibit  this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility  that waste could exhibit this characteristic.
              *

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                                REFERENCES

"Silica and Silicon," Industrial Minerals and Rocks, Vol. 2, Stanley J.
    Lefond, ed. 5th edition, Society of Mining Engineers of AIME, 1983,

U.S. Bureau of Mines, Mineral Facts and Problems, 1985.

U.S. Bureau of Mines, Minerals Yearbook 1985.

U.S. Bureau of Mines, Mineral Commodity Summaries 1987.
                                    3-197

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                                 STRONTIUM

.Strontium  is  a hard, white, alkaline-earth metal.  It is found in natural
 formations and trace amounts are produced by nuclear fission
 (strontium-90).   Strontium has chemical properties intermediate of barium
 and  calcium.  It  readily  forms compounds with water, oxygen, nitrogen,
 fluorine,  sulfur, and halogens.  Strontium metal and salts burn with a
 bright  red flame.

 Strontium  is  estimated  to comprise 0.02 to 0.03- percent of the earth's
 crust.  Igneous rocks contain approximately 375 ppm of strontium.
 Strontium  has been  found  in sedimentary formations such as beds of gypsum,
 anhydrite, dolomite, limestone, shales, or marls.  Strontium is
 commercially  produced from the mineral celestite (Strontium Sulfate), a
 white  to blue-white mineral containing 56.4 wt percent strontium.
 Strontianite  is a naturally occurring strontium carbonate, but is not
 economically  exploited.

 The  largest volume  use  of strontium  compounds is in  the manufacture  of
 glass  faceplates  for color television picture tubes, where additions  of
 strontium  oxide and barium oxide to  the glass act as radiation shielding to
 block  secondary x-rays.   Strontium compounds are used in  the pyrotechnics
 industry,  in  ferrite ceramic permanent magnets, and  is also used  in
 pigments.  Strontium carbonate can be used to remove lead  from zinc  in
 electrolysis.  In all the above industries, strontium is  used  in  a  compound
 form,  not  pure strontium  metal.  Strontium metal is  used  in aluminum-
 silicon alloys to improve casting  behavior.

 In 1986, the  United States imported  100 percent  of  the  celestite  needed to
 produce strontium.  Celestite was  imported  from  Mexico  and Spain.   The
 Celestite  imported  contained approximately  16,500  short  tons  of  strontium.
 The  one processor of strontium  in  the  United  States  is  located at
                                    3-198

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Cartersville, Georgia.  The producer uses the black ash process to produce
strontium carbonate and a number of processes to produce a vide variety of
strontium compounds.

The black ash process is shown in Figure 3-64.  Celestite ore is crushed,
ground, mixed with ground coke, and fed to a rotary kiln.  There,  the
celestite is reduced to strontium sulfide (called black ash).  The black
ash is then finely ground in a ball mill and the slurry is fed to a
leaching circuit.  The leaching circuit consists of-a series of stirred
tanks.  The black ash is dissolved with water in a countercurrent
decantation system.  The final decantation solution is filtered for
clarity.  The filtrate contains 12 to 13 wt percent strontium sulfide.  The
filtrate is sent to agitation  tank, where soda ash is added, and strontium
carbonate crystals are precipitated.

The precipitate slurry is pumped to vacuum drum filters where most of  the
liquid is removed.  Filter cake is 60 wt percent strontium carbonate, which
is sent to a carbonate dryer.

Since the United States does not mine celestite for strontium production,
no mining or beneficiation wastes are identified.  However, process wastes
include spent ore, muds, and spent carbon (Table 3-26).  Further
investigation for potential regulation under Subtitle C  is recommended.
                                   3-199

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                                Figure 3-64

                                 STRONTIUM
                             BLACK ASU PROCESS
Celescite Ore
(crushed, ground
 coke added)
 Water
 Soda ash
Rotary Kiln
                                     v
                                 Black Ash
                            (strontium sulfide)
                                     1
                               Storage bins
                                     \/
                                 Ball mill
                                Stirred  tanks
                               Counter Current
                                 Decantation
                                   Decant
                                  Solution
                                     i
                                Press Filter
                             Filtrate 12-13 wt*
                                  Strontium
                                     i
^Agitation tank
                                     T
                     muds
                   -> waste  solution

-------
 Figure 3-64 (Cont.)
BLACK ASH PROCESS CONTINUED
    Strontium Carbonate
      Crystals (ppt)
        Vacuum Drum
          Filter
Dilute sodium sulfide
solution
             V
        Filter cake
60 vtX strontium carbonate
            1
           Dryer
          Packing
            3-201

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                                                       Table  3-26

                                                    STRONTIUM  WASTES
             Process
                        Waste
Possible RCRA Characteristic*
R   C   I   T       Comments
LJ
I
CO
o
CO
             Black  Ash  Process
                        1) Filter Muds


                        2) Waste Solution
                           (agitation tank)


                        3) Vacuum Drum Filtrate
N     N   N   ?
                                                                       N


                                                                       N
      ?   N   ?


      ?   N   ?
* RCRA characteristics are Reactivity, Corrosivity, Ignitability and EP Toxicity as defined in

  40CFR 261 Subpart C.


N - Waste not expected to exhibit  this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibly that waste could exhibit this charcteristic.

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                                REFERENCES



Bureau of Mines, Mineral Commodities Summaries, 1987.




Marks, H.W., Encyclopedia of Chemical Technology, 1978.
                                   3-203

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                                 TELLURIUM

Tellurium is a nonmetal with a metallic luster,  and it  is  a semiconductor
whose conductivity increases with exposure to light.  Tellurium's principal
use is as an alloying agent in copper and stainless steel.   It  is also
alloyed with lead to improve its strength and hardness.  Minor  amounts of
tellurium are also used in the chemical and semiconducting industries and
as catalysts.

Tellurium is present in a large number of minerals, however no  tellurium
ores exist.  Tellurium is obtained only as a secondary  product  during the
recovery of other metals, primarily copper.  Commercial grade tellurium is
currently produced by only one company in the United States from copper
slimes which are byproducts of electrolytic copper refining. These slimes
may contain up to 8 percent tellurium, depending on the quality of the
copper ore used.

The recovery of tellurium from copper slimes is accomplished as shown in
Figure 3-65.  The decopperized slime is mixed with soda ash and roasted,
producing a soda slime containing tellurium, and waste solids which are
discarded.  The soda slime is leached with water to extract sodium
tellurite.  The leached slag may be wasted or returned to a copper anode
furnace for further processing.  The sodium tellurite solution is
neutralized with sulfuric acid to precipitate tellurous acid.  After
removing the tellurous acid precipitate,  the solution is treated for
selenium recovery.  The tellurous acid is refined by redissolving" it  in
sodium hydroxide solution, followed by fractional precipitation  to remove
solid impurities, which are discarded as  waste.

Tellurium metal can be produced  from  the  crude  tellurous acid by one  of  two
methods.  As shown in Figure 3-66, the crude solids can be  dissolved  in  a
caustic solution, followed by electrolytic  reduction of tellurium metal.
Washing, drying, and melting of  the metal produces the final tellurium
                                   3-204

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                               Figure 3-65

                   TELLURIUM RECOVERY FROM COPPER SLIMES
                               Copper slime
                           containing Tellurium
Soda Ash-
Wat er-
sulfuric acid
sodium hydroxide-
sodium sulfide-
                                    _V
                                  Copper
                                  Removal
  Roasting
                    >Copper
>Slag
                                        soda slime
  Leaching
•leached slag
                                        sodium tellurite solution
Neutralization/
 I'recipi tation
•liquid to selenium
 recovery
                                         precipitate
                                    _V
 Dissolution
Precipi tation
                               Neutralization/
                                Precipi tation
 >solids
                     kwastewater
                               Tellurous acid
                                 precipi tate
                                   3-205

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                               Figure 3-66



                  ELECTROLYTIC PURIFICATION OF TELLURIUM
Sodium hydroxide-
Water-
                        Crude Tellurous Acid Solids
Dissolution
                               Electrolysis  	>Vaste electrolyte
                                       cathodic deposit
  washing
wastewater
                                  Drying
                              [    Melting
                                    I
                              Tellurium Metal
                                   3-206

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metal product.  This process produces wastevater as the wastes for which
the management practices were not specified.

The second primary method of obtaining tellurium metal from crude tellurous
acid is shown in Figure 3-67.  In this process, tellurous acid is dissolved
in acid and is precipitated from solution with sulfur dioxide.  Washing,
drying, and melting are used to purify the tellurium metal product.  The
wastewater produced is disposed of in an unspecified manner.

The processes identified for the recovery and purification of tellurium
include standard unit operations used in the industry.  Besides the use of
acids,  no hazardous substances were identified as being used in the
processing.  Still, it is possible that the wastewater or slags produced
may have hazardous characteristics (Table 3-27).  Therefore, further
investigation for possible regulation under Subtitle C is recommended.
                                   3-207

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                              Figure 3-67

              PURIFICATION OF TELLURIUM DY ACID PRECIPITATION
Hydrochloric or.
Sulfuric Acid
Sulfur dioxide-
Water-
                        Crude Tellurous Acid Solids
 Dissolution
Precipitation 	^Uastewater
                                       precipitate
   Vashing
>Vastewater
                                  Drying
                               |   Melting
                              Tellurium Metal
                                  3-208

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o
vO
                                                      Table 3-27



                                                   TELLURIUM WASTES
Process
Copper Slime
Processing



Electrolytic
Purification

Acid Precipitation
Purification
Waste
1) Roasting Slag

2) Leaching Slag
3) Precipitation Solids
4) Wastewater
1) Waste Electrolyte

2) Wastewater
1) Wastewater

Possible RCRA Characteristic*
R C I T Comments
N

N
N
N
N

N
N

N

N
7
N
7

7
7

N ?

N ?
N ?
N N
N N

N N
N N

            * RCRA characteristics are Reactivity, Corrosivity,  Ignitability  and  EP Toxicity as defined in

              40CFR 261 Subpart C.



            N - Vaste not expected to exhibit this characteristic.

            Y - Strong indication that vaste would exhibit this  characteristic.

            ? - Possibly that waste could exhibit this charcteristic.

-------
                                REFERENCES




Bureau of Mines, Mineral Commodities Summary, 1987.




Marks, H.W., Encyclopedia of Chemical Technology, 1978.
                                   3-210

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                                    TIN
Cassiterite (SnO-) is the major mineral used as a source of tin.   The
mineral occurs in both vein and.lode deposits.   Metals  associated with
cassiterite in vein deposits include lead,  tungsten,  antimony,  zinc,
copper, silver, arsenic, and iron (Liddell, 1945).   The major deposit in
the United States exists in the Sevard Peninsula in Alaska, with  minor
deposits in the Rocky Mountain region of the continental United States.
Currently, only minor amounts of tin concentrate are being produced from
placer mining in Alaska and as a byproduct  from molybdenum mining in
Colorado.  Only one tin smelter is operating in the United States.  In
1986, the smelter produced approximately 3,000 short tons of tin from
imported and domestic tin concentrates, residues, and secondary
tin-containing materials.  The majority of the tin used in the United
States is either imported as metal or reclaimed from secondary materials.

Tin is relatively resistant to corrosion, and is therefore often used as a
protective coating for flat-rolled steel.  It also has a low melting point
(232°C) and is combined with lead for use as solder (EPA, 1984).   The main
industries consuming tin include cans and containers, electrical,
construction, and transportation.

The cassiterite ore is processed by crushing, grinding, and concentrating.
A number of gravity concentration and mechanical separation methods are
used.  Typical wastes produced from these processes include a slurry of
tailings and process water (Table 3-28).  The solids are usually-settled
out in a  tailings pond and the liquid either discharged  to receiving waters
or reused in the process.  Any discharge would be  regulated under  the  Clean
Water Act.

Tin concentrates are processed in one smelter  (Figure  3-68)  located  in
Texas City, Texas.  There are a number  of  factors  that  complicate  the
smelting of  tin.  A high  temperature  is  necessary  to reduce  tin  dioxide
                                   3-211

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                                                  Table 3-28

                                                  TIN WASTES
Process
Waste
Possible RCRA Characteristic*
R    C    I    T    Comments
Reverberator Furnace

Electrorefining
                                  Scrubber Liquor

                                  Waste Electrolyte
N    N

N    ?
                                        N

                                        N
                    Arsenic
* RCRA characteristics are Reactivity, Corrosivity, Ignitability, and EP Toxicity  as  defined in 40 CFR 261
    Subpart C.

N - Waste not expected to exhibit this characteristic.
Y - Strong indication that waste would exhibit this characteristic.
? - Possibility that waste could exhibit this characteristic.

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                    Figure 3-68

                    TIN SMELTING
            Tin Concentrates  and  Residues
Tin Product
                  Coke
                   X
   1
Limestone
                      Smelting
                      Furnace
                        Anode
                       Casting
                      Electro-
                      Refining
Casting
                   (1) Off Gas  to  Scrubber
                   (2) Slag
                   (3)  Cell Slimes to
                       recycle
                   (A)  Waste Acid
                      3-213

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with carbon.  At this temperature, a number of other metal oxides are also
reduced.  The other metals form compounds with tin that have very high
melting points.  These compounds are termed "hardhead".  At the smelting
temperature, tin is also very fluid and soaks into the refractories.   These
factors decrease the recovery of tin from smelting operations.   In an
attempt to increase recoveries, tin processing has been divided into  two
phases.  The first phase involves smelting for primary separation. The
slag, hardhead, and drosses produced are reprocessed in a second stage of
smelting for additional tin recovery.

The reverbatory furnace of the smelter is equipped with a caustic scrubber
to control sulfur dioxide emissions.  Approximately SOX of the wastewater
from the scrubber is recycled in the process.  The EPA studied the Texas
City smelter in 1984 and reported a production normalized discharge of
21,670 liters of wastewater for every metric ton of tin produced  (EPA,
1984).  These wastevaters are currently treated by chemical precipitation
and sedimentation.  PEI Associates found that arsenic exceeded the EP
toxicity limits in the scrubber wastes (PEI, 1984).

The tin from the smelter is cast into anodes that are used in an
electrorefining process to produce a more pure product.  Electrorefining
can operate with either an acid or alkaline bath.  The acid bath  contains
stannous sulfate, creosulfonic or phenolsulfonic acids, and free  sulfuric
acid with beta naphthol and glue added (Grayson, 1978).  If the  lead
content of the anodes is high, slimes collect on the anodes.  In  this case,
the anodes are removed from the bath and scrubbed regularly to remove the
slimes.  The alkaline bath contains potassium or sodium stanite  and  free
alkali.  In this operation, lead plumbite is precipitated  and generated as
slime.  The pure tin generated from electrorefining is recast  into ingots
and shipped out as product.

The casting processes should generate foundry sands.   These sands typically
contain some heavy metals, but are not usually hazardous.   Electrorefining
generates waste slimes and possibly waste baths.  Both the slimes and  the
                                    3-214

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electrorefining solutions are probably fairly high in heavy metals.  The
slimes are packaged and shipped to England for reprocessing.   PEI
Associates found that no vastes were generated by the.refining process
(PEI, 1984).

The Texas City tin smelter produces several vastes that either have been
shown to be hazardous or have the potential to be hazardous.   Therefore,
further study of this smelter for potential regulation under Subtitle C is
recommended.
                                   3-215

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                                REFERENCES

Belyayev, D.V.; A Handbook of the Metallurgy of Tin; MacMillan Company; Nev
     York, Nev York, 1963.

Grayson, Martin, exec, ed.; Encyclopedia of Chemical Technology;
     Wiley-Interscience; New York, Nev York, 1978.

PEI Asociates, Inc. Overvlev of Solid Waste Generation, Management and
     Chemical Characteristics Primary Antimony, Magnesium, Tin and Titanium
     Smelting and Refining Industries Industrial Environmental Research
     Laboratory, Office of Research and Development, U.S.E.P.A. Cincinnati,
     OH, Dec. 1984 (EPA Contract No. 68-031-3197).

U.S. Department of the Interior, Bureau of Mines; Mineral Commodity
     Summaries; U.S. Bureau of Mines; Washington, D.C.; 1987.

U.S. EPA; Development Document for Effluent Limitations, Guidelines, and
     Standards for Nonferrous Metals. Point Source Category, Phase II,
     Supplemental Development Document for Primary and Secondary Tin; U.S.
     EPA; Washington, D.C.; 1984 (EPA-440/l-84/019b).

Wright, P.A.; Extractive Metallurgy of Tin; Elsevier Science Publishing
     Co., Inc.; Nev York, Nev York; 1982.
                                   3-216

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                                 TITANIUM

Titanium's high strength to weight ratio and its  resistance  to  corrosion
make its alloys (principally with aluminum and vanadium)  excellent
replacements for steel in aircraft and spacecraft applications,  and in the
chemical and power generation industries.  However,  its  principal use is as
a pigment for paints, rubber, paper,  plastics, etc.  because  of  titanium
dioxide's (TiO-) whiteness and high refractive index.

The tvo major mineral forms of titanium are ilmenite (FeO.Ti02) and rutile
(high temperature polymorph of TiO-).  Ilmenite is generally 43-652 TiO-
while rutile contains approximately 95Z
U.S. production of titanium metal and titanium oxide in 1986 is estimated
to be 17,400 and 917,000 short tons, respectively.  Five companies
operating 11 plants in 8 states were producing titanium oxide while 4
companies were producing titanium sponge metal.  Titanium sponge metal was
derived almost entirely from rutile.

Titanium minerals occur in hard rock deposits or beach/alluvial sands
("black sands").  The major United State's hard rock deposits of ilmenite
are the Sanford Lakes deposits in the Adirondack Mountains of New York..
Other hard rock deposits of ilmenite and/or rutile occur in Virginia, North
Carolina, Arkansas, Vyoming, and California.  The Maclntyre Development  of
NL Industries in Nev York is the major hard rock mining operation and  is
currently inactive.  The major deposits and mining of  titanium minerals
from beach/alluvial sands are  in the Atlantic and Gulf Coastal Plain
geologic provinces.

Hard rock mining and beneficiation  consist of open pit mining  followed  by
ore crushing, grinding, classification, magnetic  separation, and  flotation.
As shown in  Figure 3-69 (adapted from Maclntyre Development),  a main
feature of the beneficiation process is the use of magnetic  separators  to
                                    3-217

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                Figure 3-69

            TITANIUM BENEFICIATION
      NEV YORK UARDROCK ILEMNITE DEPOSITS
Magnetite
 Magnetite
 Ilmenite
                      ORE
                     A.
                     Size
                   Reduction
                   Screening
 Magnetic
Separation
                     Size
                   Reduction
 Magnetic
Separation
                     Size
                  Separation
                     Froth
                   Flotation
                    Magnetic
                   Separation
             (2)
                Tailings
             (3)
                Tailings
 Devatering
                     3-218

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remove magnetite.  Magnetite has been used as a blast  furnace  feed,  in
refractories, and as a component of a heavy medium for coal  separation.
The tailings from separators and flotation cells are the major waste
produced, and are not expected to exhibit any hazardous characteristics.

Figure 3-70 shows a schematic of the beneficiation of  the beach deposits.
Sands from dragline or front end loader excavation,  or from  suction
dredging are first spiral concentrated to remove low density tails.   The
ilmenite/rutile rich sand is then dried and subjected  to a high tension
(electrostatic) separator where the quartz and other nonconducting minerals
are thrown off the rotors.  These nonconducting materials are  processed to
produce a zircon and monazite product, and quartz and  epidote  waste.  The
conducting fraction undergoes further magnetic separation to separate
ilmenite from rutile, and the rutile fraction is screened, and lastly
cleaned in a high tension separator.  Oversized quartz vaste is produced.
None of the wastes from beach sand processing are expected to  exhibit any
hazardous characteristics.

Treatment of the lower grade ilmenite and high grade rutile  to produce
pigment grade titanium oxide is by the sulfate and chloride  processes,
respectively.  The highest grade rutile concentrates can also  be used in
the chlorine process, as is done by the largest U.S. pigment producer.  The
sulfate process generates large, costly, quantities of sulfuric acid waste
(2 times the product weight), so sulfate processing of ilmenite has been
cut back in recent years producing only about 14% of U.S. titanium dioxide
output in 1986.  The trend today is production of rutile substitutes by
upgrading ilmenite to greater than 90% TiO- purity by partial reduction and
leaching with sulfuric acid and hydrochloric acid or by electric  furnace
smelting to produce high TiO« slags.  The  leached product is  referred  to  as
synthetic rutile.  Kerr-McGee Chemical Corp. has  the only synthetic rutile
plant in the U.S. at Mobile, Alabama.

The sulfate process for production of  titanium dioxide  from ilmenite  is
shown in Figure 3-71.  Ilmenite ore or high  titanium oxide slag is  digested
                                   3-219

-------
             Figure  3-70

        TITANIUM DENEFICIATION
          DEACU SAND DEPOSITS
Ilmenite<
Rutile
                 Sands
                Spiral
               (Density)
              Separators
             -»(l)Tailings
                 Dryer
                  _v
             Electrostatic
              Separators
               >(2)Non-Conductors
                   (to further processing)
   Magnetic
  Separators
              Screening
             Separation
               >(3)0versize
                   Quartzite
Electrostatic
 Separation
rM2)Non-conductors
     (to further processing)
                  3-220

-------
      Figure 3-71
   TITANIUM PROCESSING
     SULFATE PROCESS
H2SV
Scrap,
Iron
              Ilmenite Ore
                   or
              High Ti02 Slag
       Extraction
               TiOSO,
      Clarification
Sludge
   Vacuum Evaporation
   and Crystallization
       Filtration
        FeSOA-7H20
        (Copperas)
         Vacuum
       Evaporation
            &
      Heating 90°C
               TiO(OH)2
               (Titania hydrate)
         Filter
      -» Filtrate
         Waste
        Washing
        Wastevater
        Calcining
      Ti02  Product
          3-221

-------
with sulfuric acid to form a porous cake that is dissolved  in  diluted acid
to form titanyl sulfate (TiOSO,).  The iron scrap keeps  the iron  impurities
in the ferrous state to facilitate washing of the titanium  oxide  eventually
produced.   The titanyl sulfate solution is,clarified,  concentrated to
crystallize copperas,  and filtered to remove sludge (waste)  and  ferrous
sulfate heptahydrate (copperas) product, respectively.   The filtered
titanyl sulfate solution is vacuum evaporated to achieve the  desired
concentration and hydrolyzed at a temperature of 90°C to cause
precipitation of hydrated titania (TiCKOH^).  The titania  hydrate is
filtered,  washed, and calcined at 1000°C to produce titanium  dioxide
product.   Crystallization of copperas is not required with  low-iron feeds
such as high-TiO- slag.

The chlorine process, shown in Figure 3-72, converts rutile or high grade
ilmenite to titanium chloride (TiCl^).  This occurs in a fluid bed
chlorinator where petroleum coke is added as a reductant.  Volatile
titanium chloride and other metal chlorides are separated by fractional
condensation, double distillation, or chemical treatment.  Chemical
treatment  is largely to remove vanadium chloride which has  a similar
boiling point to that of titanium chloride.  The vanadium chloride is
complexed  with mineral oil and reduced  to VOC12 by H-S.   A  major waste
product is ferric chloride.  The final step is oxidation at 985°C where
aluminum chloride facilitates formation of the rutile crystal.  The
chlorine gas formed during oxidation is recycled to the  fluid bed
chlorinator.

The Kroll process is the major commercial  process  for production of
titanium sponge metal.  As shown in Figure 3-73, titanium  chloride  is
reduced by liquid magnesium in an argon or helium  atmosphere.  The  molten
magnesium chloride that forms is drawn  off the bottom and  is  reduced  by
electrolysis to produce magnesium metal for  reuse, and  chlorine gas.
Magnesium chloride impurities, unreacted  titanium  chloride, and magnesium
residuals of the sponge metal are removed  by acid  leaching or vacuum
                                   3-222

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Petroleum Coke
      Cl,
    Mineral Oil
       Cl.
                            Figure 3-72
                        TITANIUM PROCESSING
                         CHLORIDE PROCESS
                                   Rutile or
                                   High Grade/Processed
                                       Ilmenite
 Fluid Bed
Chlorinator
                                                        Non-reacted
                                                        Solids to
                                                           Waste
                                    TiCl, .& Other
                                   Metal Chlorides
                            Fractional
                           Condensation
                        FeCl3 to Uaste
                                    TiCl, & Trace
                                    Impurities
                              Double
                            Distillation
  Chemical
 Treatment
 Oxidation
     at
    985°C
                                T
                            Ti02 Product
                           -•» Trace Metal
                              Chlorides
                                                    voci.
Aluminum Chloride
                                3-223

-------
                                Figure  3-73
                            TITANIUM PROCESSING
                               KROLL PROCESS
     Waste
HNO-j or HC1
                 Sponge
                Removal
Acid
Leach
                Drying
               Crushing
               Screening
                                Reduction
                                 Reactor
                            MgCl
                                2 ^
           Electrolysis
•Cl.
                                                  MgCl.
                           Vacuum
                        Distillation
 Sponge
Removal
                                            Sponge in
                                              23 kg
                                              Drums
                                   3-224

-------
distillation.  The acid leaching produces a waste and the vacuum
distillation produces magnesium chloride for recycling.

The sponge metal can be cast into ingots or powdered.  Ingots can be milled
by forging, hot or cold rolling, and extrusion.

A variety of hazardous and non-hazardous wastes  are produced in the mining,
beneficiation, and processing of titanium (Table 3-29).   The
mining/beneficiation of titanium ores produce tailings that are unlikely to
have hazardous characteristics.  The sulfate process produces large
quantities of waste sulfuric acid and ferrous sulfate.  It is reported
(Lefond, 1983) that the sulfuric acid and ferrous sulfate (copperas), that
are not sold as products,  are discharged to waterways or the ocean.  The
chlorine process produces  largely ferric chloride which is dumped in the
ocean or reused in water treatment as a flocculant.  Although the Clean
VAter Act necessarily regulates all discharges to waterways and the ocean
by permits, (necessitating treatment of the wastes), the hazardous
characteristics of many of these wastes or sludges produced in  the
treatment of these wastes  should be further investigated to determine if
possible regulation under  Subtitle C is appropriate.
                                   3-225

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                                                          TABLE  3-29


                                                  TITANIUM PROCESSING WASTES
                                                                        Possible RCRA
                                                                        Characteristics
I
N>
to
Process
Hardrock Ilmenite Deposits
Size Separation
Flotation
Hagnetic Separation
Ilmeni te/Rutile Beach Deposits
Spirals
Non-Conductor Processing
Vibratory Screen
Sulfate Process
Clarification
Fi Itration
Chloride Process
Fluid Bed Chlorinator
Fractional Condensation
Double Distillation
Chemical Treatment
Kroll Process
Electrolysis
Acid Leach
Waste

(1) Tailings
(2) Tailings
(3) Tailings

(1) Tailings
(2) Quartz Epidote
(3) Oversize Quartzite

Sludge
Copperas

Non-Reacted Solids
Ferric Chloride
Trace Metal Chloride
voci2

Chlorine Gas
MgCl2, TiCl^, Mg residuals
* RCRA characteristics are reactivity, corrosivity, ignitability
Subpait C.
N - Waste not expected to exhibi
Y - Strong indication that vaste
? - Possibility that waste could

t this characteristic.
vould exhibit this characterist
exhibit this characteristic
R

N
N
N

N
N
N

N
N

N
N
N
N

N
N
i


ic

C

N
N
N

N
N
N

7
N

N
7
7
7

N
N
and EP


.

I

N
N
N

N
N
N

N
N

N
N
N
N

N
N
toxici




T Comments

7
7
7

N
N
N

1
7

7
7
7
N

N
N
ty as defined in 40 CFR 261





-------
                                REFERENCES

Bureau of Mines, 1987.  Mineral Commodities Summary, 1987.

Lefond, Stanley J., ed.; Industrial Minerals and Rocks, 5th edition;
     American Institure of Mining, Metalleurigical, and Petroleum
     Engineers, Inc.; New York, New York; 1983.

Marks, 1978.  Encyclopedia of Chemical Technology, Marks, H.F., et al.,
     editors; Wiley Interscience, Nev York, Nev York, 1978.
                                    3-227

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                                 TUNGSTEN

Tungsten occurs in over 20 different minerals.   The four minerals  of
commercial importance are ferberite (FeVO^),  huebnerite (MnW04),  scheelite
(CaVO,), and wolframite ((Fe,Mn)UO^).   These  minerals are found in
association with metamorphic rocks and granitic igneous rocks.,

Tungsten deposits in the United States lie in two north-south bands from
Montana and Idaho to southern California and  Arizona and from South Dakota
to Colorado.  United States tungsten reserves amount to approximately
125,000 metric tons of metal (Marks, 1978).   Tungsten mines are usually
underground and are fairly small, producing less than 2000 metric tons of
raw ore per day (Marks, 1978).  Production has continued to decrease over
the past five years, with only three mines operating in 1986.

The majority of tungsten is used as tungsten  carbide for wear resistant
applications.  Some tungsten is used in metallic form as an alloy additive
to steel.  Metallic tungsten is also used in  lamp filaments, furnace
elements, heat shields, and arc-lamp electrodes.  The nonmetallurgical uses
of tungsten include organo-tungsten dyes and  pigments, phosphors,  and
catalysts in petroleum refining.

Scheelite and wolframite are the major tungsten containing minerals.  Ores
containing these minerals are generally very friable and overgrinding can
cause sliming problems.  Therefore, the ores  are generally crushed and
ground in stages and waste fines are kept to a minimum.  Concentration of
the tungsten is usually accomplished by froth flotation, supplemented by
leaching, roasting, or magnetic or high tension separation.  The  choice of
separation method depends on ore type as summarized  in Table 3-30.   The
tailings from froth flotation usually are sent  through a reprocessing and
scavenger froth flotation circuit  to maximize tungsten  recovery.  The
beneficiation processes vary with  the type of ore  being  mined.  A general
flow diagram is shown  in Figure  3-74, with ore-specific  information
                                    3-228

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                                 Table 3-30

                  Common Approaches to Mineral Separation
             Ore                            Process
Scheelite, simple ore 	  Gravity,  flotation,  magnetic

Scheelite, sulfides 	  Gravity,  sulfide flotation,
                                        roasting,  magnetic

Scheelite-cassiterite
  concentrate	  Electrostatic

Scheelite-calcite-apatite 	  Flotation, gravity,  leaching

Scheeli te-powerli te
  concentrate 	  Chemical  processing

Wolframite, simple ore 	  Gravity,  flotation,  magnetic

Volframite-cassiterite ore 	  Gravity,  flotation,  magnetic

Wolframite-scheelite
  concentrate 	  Magnetic

Volframite-sulfides 	  Sulfide flotation, gravity,
                                        magnetic
                                   3-229

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    Figure 3-74
TUNGSTEN PROCESSING
      RAW ORE
     Grinding
      Milling
     Screening
        _v
  -> Waste Fines
     Flotation
     Separation
                            Regrind
                              Mill
            Concentrate
      Scavenger
      Flotation
     Thickener
Waste Water
                     Waste
                     Water
                                          Fines
  Tailings
   Waste
   Water  ^
  Tailings
    Pond
    Magnetic
   Separator
 Solid
 Waste
Discharge
    Concentrate
        3-230

-------
presented below.  The tailings and any wastewaters from thickeners or other
separators are sent to tailings ponds.  Waters from the tailings ponds are
usually discharged to surface waters, with the waste fines remaining in the
tailings ponds.

The concentrate may be retreated by roasting (Figure 3-75).   Roasting
removes impurities such as sulfur, arsenic, and organic residues from
flotation.  These compounds are oxidized and volatilized.   The roaster
usually is equipped with a wet scrubber that generates wastewater.

After preparation of the concentrate, the concentrate is processed to
ammonium paratungstate (APT) via either sodium tungstate or tungstic acid.
The process is dependent on the original ore type.

Scheelite is most commonly processed  by acid leaching (Figure 3-76).  The
concentrate is leached with hydrochloric acid  to remove phosphorous,
arsenic, and sulfur.  The mixture is  filtered  and  the solids washed with
dilute hydrochloric acid.  The insoluble tungstic  acid is then digested
with aqueous ammonia to solublize the tungsten as  ammonia tungstate.  The
solution is separated from any remaining solids and magnesium oxide added.
Magnesium ammonium phosphates and arsenates are precipitated.  Activated
carbon is added to purify the solution.  The activated carbon and
precipitates are removed from the solution by  filtration.  Ammonium
paratungstate  (APT) is formed by crystallizing it  from solution.  The APT
crystals are filtered, washed, and dried.  The drier  is equipped  with a
scrubber that  generates wastewater high in ammonia.   This waste water  is
usually treated and discharged.

Lower grade scheelites are sometimes  processed by  the high pressure  soda
process (Figure 3-77).  The concentrate is ground  and digested  in an
autoclave with sodium carbonate.  This produces a  sodium  tungstate  solution
that is filtered and further  processed to  CaWO, or APT.
                                    3-231

-------
    Figure 3-75
TUNGSTEN PROCESSING
   Scheelite or
    Wolframite
    Concentrate
         \/
      Roasting
Scrubber
         V
      Prepared
     Concentrate
 Waste
 Water
        3-232

-------
                                Figure 3-76
                            TUNGSTEN PROCESSING
                          SCHEELITE ACID LEACHING
Hydrochloric
 acid (HC1)
Dilute HC1
Wash Water
Aqueous
Ammonia
Magnesium-
  Oxide
Activated-
 Carbon
 Wash-
 Vater
Wash-
Vater
                           Scheelite Concentrate
   Leaching
  Filtration
  Digestion
                                   _V
Precipitation
                                   _V
 Adsorption
  Filtration
                                    APT
                              Crystallization
  Filtration
                                Drying  of
                               APT  Crystals
                                   •I
                                     APT
                                  Crystals
  Fumes
   Waste  Acid
   Washings
-> Waste
   Solids
> Waste
 Filter Cake
   Mother Liquor
   & Washings
                  Fumes
      V
    Acidic
   Scrubber
   Water to
  Treatment
& Discharge
                               Wastevater
                              to Treatment
                             and Discharge
                                   3-233

-------
              Figure  3-77
          TUNGSTEN PROCESSING
      niGIl PRESSURE SODA PROCESS
               Low Grade
               Scheelite
                  1
               Grinding
NaCO.
Digestion
              Filtration
                Sodium
               Tungstate
               Solution
                     -> Filter
                       Coke
                 3-234

-------
Scheelite or wolframite can be converted to sodium tungstate solution by
the alkali roasting process (Figure 3-78).   Sodium carbonate is mixed with
the concentrate and the mixture heated.  The roasted concentrate is then
leached vith hot water.  The leachate, which contains sodium tungstate,  is
separated from the solids by filtration and sent to other processes for
conversion to APT.

Wolframite and scheelite concentrates are commonly processed by the Liquid
Ion Exchange (LIX) process (Figure 3-79).  The concentrate is digested
using a strong base or acid.  The digested slurry is filtered and washed.
The filtered cake is treated to remove silica and solubilize the tungsten.
The solution is filtered to remove solids,  then treated to precipitate
molybdenum.  The molybdenum solids are removed and the pH of the solution
adjusted.  The tungsten is extracted from solution using a solvent
extraction circuit consisting of two stages of extraction, washing, and
stripping.  APT is crystallized from the resulting solution.

Sodium tungstate solution from the high pressure soda process and  from  the
alkali roasting process is converted to APT by two processes.  The first
involves using the latter part of the LIX process described above.  The
second consists of conversion of the sodium tungstate solution  to
"synthetic" scheelite and processing this to APT by  the acid leaching
process.  This is diagrammed in Figure 3-80.

Dried APT is reduced to tungsten generally by one of two methods (Figure
3-81).  The first process is a two stage reduction  for metal to  be used  in
lamp filaments.  Hydrogen is used in  the first reduction and aluminum,
potassium, and silicon dopants are added to the second reduction.  The
metal is washed with hydrochloric acid,  then cast  into ingots.   The  second
process also consists of a stepwise reduction.  The  wastes  generated  are
mainly air pollution control dusts and scrubber wastewater.
                                    3-235

-------
                 Figure 3-78
              TUNGSTEN PROCESSING
            ALKALI ROASTING PROCESS
                 Scheelite or
                  Wolframite
                  Concentrate
NaCO.
    Roasting  [
 Hot -
Water
->   Leaching
                 Filtration
                          Filter
                           Coke
                    Sodium
                   Tungstate
                   Solution
                      3-236

-------
                      Figure 3-79
                    TUNGSTEN PROCESSING
                LIQUID ION  EXCHANGE  PROCESS
                         Slurried
                        Concentrate
                         Digester
      Wash
     Water
(Al,  Mg) S04	
Mother Removal-
From Solvent
Extraction
                         Filter
 Water
      Na-S
     HnSO,-
Water
Washed
Solids
                        Si Removal
                          Filter
                                                       Filter
                                                        Cake
                        Mo Removal
                          Filter
                            v
                                                      Mo Solids
                            pH
                        Adjustment
                                 Sodium Tungstate
                                     Solution
                             v
                        Continued on
                         Next Page
                          3-237

-------
                        Figure  3-79 (Cont.)
                       TUNGSTEN PROCESSING
                   LIQUID ION EXCHANGE PROCESS
Solvent
                          Wolframite or
                      Scheelite  Concentrate
                Solvent
                           Extraction
                             Uashing
           Wash
          Water
                            Stripping
                               _v
                            Filtration
                               APT
                         Crystallization
Filtration
                             Drying
                           APT  Crystals
                     ~> Wastevater
                     -> Wastevater
                        ->  Waste
                         Solvent
                           Filter
                            Cake
-^Mother Liquor
   & Washings
                           Scrubber
                              l^
                           Scrubber
                          Wastevater
                              3-238

-------
              Figure 3-80
          TUNGSTEN PROCESSING
      SODIUM TUNGSTATE CONVERSION
CaCl,
                Sodium
               Tungstate
               Solution
Precipitation
              Separation
                         Waste
                                   Supernatant
                   v
                 CaVO,
         "Synthetic" s"cheelite
                 3-239

-------
                               Figure 3-81
                            TUNGSTEN PROCESSING
                           REDUCTION TO TUNGSTEN
                   Hydrogen^
               APT
Hydrogen-
Stepvise
Reduction
                             Hydrogen
                                   Purification
                                     Scrubber
Scrubber
  Waste
  Water
                               .Fumes
                                From
                             Non-Hydrogen
                              furnaces
Air Pollution
'Control Devices
\
i
           Tungsten
            Ingots
                                   Air Pollution
                                   Control Dust
                                   3-240

-------
Although the processes and wastes from the production of tungsten are
fairly veil documented,  waste management  practices are not  well known
(Table 3-31).   Further study of this industry is recommended to determine
if possible regulation under Subtitle C should be considered.
                                   3-241

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       Table 3-31
TUNGSTEN PROCESSING WASTES
Possible RCRA
Characteristics
Process
Raw ore beneficial ion




Concentrate Roasting
Scheelite Acid Leaching





High Pressure Soda Process
Alkali Roasting Process
Liquid Ion Exchange (LIX)
Process





•

Waste
Fines
Tailings
Thickener Waste Water
Solid Waste from the
Magnetic Separator
Scrubber Wastewater
Acidic Scrubber Water
Hydrochloric Acid
Solids from Digestion
Filter Cake
Mother Liquor and Washings
Ammonia Scrubber Water
Filter Cake
Filter Cake
Digester Filter Cake
Silicon Removal Filter Cake
Molybdenum Solids
Solvent Extraction Wastewater
Solvent Washing Wastewater
Solvent
Filter Cake
Mother Liquor and Washings
Scrubber Water
R
N
N
N

N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
C
N
N
N

N
7
7
7
7
N
7
?
N
N
N
N
N
7
7
N
N
7
7
I
N
N
N

N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
7
N
N
N
T Comments
7
7
7

7
7
/
7
7
- 7
7
7
7
7
7
7
7
7
7
N
7
7
7

-------
                                              Table 3-31 (Cont.)

                                          TUNGSTEN PROCESSING WASTES
         Process
       Waste
 Possible RCRA
 Characteristics

R    C    I    T
Comments
Sodium Tungstate Conversion
Supernatant from Separation   N
          N
Reduction to Metallic Tungsten    Scrubber Water                N    ?    N    ?
                                  Air Pollution Control Dust    N    N    N    ?
* RCRA characteristics are reactivity, corrosivity, ignilability, and EP toxicity as defined  in  40 CFR 261
  Subpart C.

N - Waste not expected to exhibit  this characteristic.
Y - Strong indication that waste would exhibit  this characteristic.
? - Possibility that waste could exhibit this characteristic.

-------
                                REFERENCES

EPA; Development Document for Effluent Limitations Guidelines for the
     Nonferrous Metals Manufacturing Point Source Category;  EPA; 1983
     (EPA-440/l-83/019b).

EPA; Development Document for Effluent Limitations Guidelines and Standards
     for the Ore Mining and Dressing Point Source Category;  EPA; 1982.

Mark, H.F., et al.f ed.; Encyclopedia of Chemical Technology; Wiley-
     Interscience; New York, N.Y.; 1978.

Yen, S.W.H. and C.T. Wang; Tungsten;  Sources, Metallurgy, Properties, and
     Applications; Plenum Press; New York, N.Y.; 1979.
                                   3-244

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                                 VANADIUM

Vanadium is a transition metal that is very soft and ductile  in its  pure
form and has a high melting point.  It is used mainly as an alloying agent
to produce high strength steels.  The metal is also used in  the production
of titanium alloys and as a catalyst in chemical production  processes.

There are approximately 65 known minerals that contain vanadium (CSMMF,
1961).  However, vanadium is widely distributed, with deposits usually less
than 1-2 percent vanadium by weight.  Therefore, extraction  of vanadium
ores is usually associated with the mining of another mineral.  In the
U.S., vanadium is found in clays in Arkansas, in uranium bearing sandstones
in the Colorado Plateau, in titaniferous magnetites distributed throughout
the U.S., and with phosphatic shales and phosphate rock in Idaho and
Wyoming.

In 1986, the vanadium industry was composed of 14 firms, 8 of which
extracted vanadium from raw materials.  The remainder were involved in
vanadium pentoxide processing.  The raw materials used included
ferrophosphorous slags produced in Idaho, Arkansas clay, petroleum
residues, utility ash, and imported iron slags (Bureau of Mines, 1987).
Umetco's Arkansas mine was closed in 1985 and remains closed.  The majority
of the mines in Colorado and Utah where vanadium was coproduced with
uranium were closed due to the low demand for domestic uranium.  Some of
the phosphate mines in Idaho and Wyoming produced slags from which vanadium
was recovered.

Each producer of vanadium materials used a somewhat  different  process
depending on the final product desired and other  factors.  A  generic
description of vanadium processing  is presented here (Figures  3-82  through
3-85).  The first step in  the extraction of  vanadium from any  ore source  is
the production of an  oxide concentrate usually  by  crushing and screening.
The concentrate is mixed with a sodium salt,  and  roasted  to  convert  the
                                    3-245

-------
                     Figure 3-82

       VANADIUM - SODIUM HEXAVANDATE PRODUCTION
                   Vanadiurn-bearing
                       Material
Sodium Salt
Water-
Sulfuric Acid
Wash Vater-
                       Crushing
                        Mixing
                       Roasting
                       Leaching/
                      separation
                            solution
                    Precipitation
                     Filtration
                        Sodium
                      Hexavandate
-$> Solid  Residues
   Filtrate
                          3-246

-------
                             Figure 3-83

                  VANADIUM - VANADIUM PENTOXIDE  PRODUCTS
Option 1
                                  Sodium
                                Hexavandate
                                    I
                                  Fusion
                                 Vanadium
                                 Pentoxide
Option 2
         Sodium 	
         Bicarbonate
         Solution
         Ammonium
         Chloride
                                  Sodium
                                Hexavandate
 Dissolution
                               pH Adjustment
Precipitation
                                Filtration
                                Calcination
                                 Vanadium
                                 Pentoxide
                     -^Precipitate
                       (impurities)
                     -^Filtrate
                                    3-247

-------
                Figure 3-84

        VANADIUM - CALCIUM REDUCTION
                  Vanadium
                  Pentoxide
Calcium-
Iodine—
Vacuum
Heating
•Slag
                  Metallic
                  Vanadium
                     3-248

-------
                  Figure  3-85

      VANADIUM - ALUMINOTHERMIC REDUCTION
Aluminum
                   Vanadium
                   Pentoxide
Bomb Reduction
->Slag
                     _v
                           Vanadium-
                           aluminum alloy
                 I  Crushing
1 Dealuminization
\
Vanad
/
Electron Beam
Melting
                   Vanadium
                     Ingot
                      3-249

-------
oxide to sodium metavanadate (NaVO-j).  Water is added to dissolve the
compound, then sulfuric acid is added to adjust the pH to 2-3 and
precipitate sodium hexavanadate (Na,V,0.,).   The precipitate is separated
from solution and fused at 700°C to produce  a technical grade vanadium
pentoxide.  The precipitate may also be dissolved in a sodium bicarbonate
solution.  Iron, aluminum, and silicon impurities can then be precipitated
by pH adjustment and removed from solution.   Ammonium chloride is added to
precipitate ammonium metavandate.  This precipitate can be calcined to
produce vanadium pentoxide.

Ferrovanadium can be produced by the addition o*f vanadium ore, slag, or
technical grade oxide to iron prior to charging the blast furnace.
Vanadium metal can be produced by either calcium reduction or the
aluminothermic process.  Calcium reduction involves combining vanadium
pentoxide vith calcium, adding iodine as a flux, and heating the mixture in
a vacuum to form metallic vanadium.  The aluminothermic process consists of
reacting vanadium pentoxide in a bomb to form a vanadium aluminum alloy.
The alloyed aluminum and dissolved oxygen are removed in a high temperature
vacuum processing step.  The resulting vanadium sponge is melted by an
electron beam to produce a vanadium ingot.  A number of other methods have
been used on a trial basis, including iodine-refining, electrolytic
refining, and electrotransport, but none are knovn to be used in full scale
processing.

Wastes produced from processing of vanadium-bearing materials include solid
and liquid residues from the initial leaching process (Table 3-32).  If a
more pure vanadium pentoxide is desired, waste precipitate and filtrate are
produced from additional processing.  The solid residues from leaching of
ferrophosphorous slag are returned to the phosphorous recovery process, but
the residues from leaching of vanadiferous clays and cannotite ores
associated with uranium recovery are not reprocessed.  A National  Academy
of Sciences report in 1974 stated  that  these residues are "likely  to  be
                                   3-250

-------
                                                    Table  3-32

                                               VANADIUM WASTES
       Process
                        Waste
                                   Possible RCRA Characteristic*
                                   R   C   I   T       Comments
UJ
I
       Sodium Hexavanadate
       Production

       a.  Leaching
b.  Filtration

Vanadium Pentoxide
Production

    Option 2
       Production of Metallic
       Vanadium

       a.  Calcium Reduction
       b.  Aluminotherraic
           Reduction
                        Solid Residues
                               Filtrate
Precipitate (impurities)
Filtrate
                        Slag

                        Slag
                                   N   N   N
                                   N
        N
N   N   N   ?
N   ?   N   ?
                                   N   N   N   ?

                                   N   N   N   ?
                  May be  processed
                  for recovery of
                  other metals
       * RCRA characteristics are Reactivity, Corrosivity, Ignilability and EP  Toxicity as defined in
         40 CFR 261 Subpart C.

       N - Waste not expected to exhibit this characteristic.
       Y - Strong indication that waste would exhibit this characteristic.
       ? - Possibility that waste could exhibit  this characteristic.

-------
heaped on the ground or perhaps used as landfill."  The current management
practices for solid residues are not reported.   It is not clear how liquid
wastes from processing are handled.

Although the vanadium industry is currently relatively small,  it could
become larger if uranium mining on the Colorado Plateau resumes.  Further
study is recommended for potential regulation under Subtitle C.
                                   3-252

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MW-MISC/56
                               BIBLIOGRAPHY

Bureau of Mines, 1987 Mineral Commodity Summaries,  U.S.  Dept.  of Interior,
    1987.

Mark,  H.F., ed., Encyclopedia of Chemical Technology,  John Wiley & Sons,
    1983.
                                   3-253

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