EPA-600/2-77-127
July 1977
Environmental Protection Technology Series
                              CLOSED LOOP  SYSTEM
                           FOR THE TREATMENT OF
                             WASTE PICKLE LIQUOR
                               Industrial Environmental Research Laboratory
                                    Office of Research and Development
                                   U.S. Environmental Protection Agency
                               Research Triangle Park, North Carolina 27711

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                      RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental Protection
Agency, have been grouped into five series. These five broad categories were established to
facilitate further development and application of environmental technology. Elimination of
traditional grouping was consciously planned to foster technology transfer and a maximum
interface in related fields. The five series are:

    1.  Environmental Health Effects Research
    2.  Environmental Protection Technology
    3.  Ecological Research
    4.  Environmental Monitoring
    5.  Socioeconomic Environmental Studies

This report has been assigned to the ENVIRONMENTAL PROTECTION TECHNOLOGY
series. This series describes research performed to develop and demonstrate instrumenta-
tion, equipment, and methodology to repair or prevent environmental degradation from point
and non-point  sources of pollution. This work provides the new or improved technology
required for the control and treatment of pollution sources to meet environmental quality
standards.
                            EPA REVIEW NOTICE

This report has been reviewed by the U.S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents necessarily reflect the views and
policy of the Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.

This document is available to the public through the National Technical Information Service,
Springfield, Virginia 22161.

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                                    EPA-600/2-77-127
                                           July 1977
 CLOSED LOOP SYSTEM
FOR  THE  TREATMENT OF
 WASTE PICKLE  LIQUOR
                 by

             Joseph C. Peterson

          Crown Chemical Company, Inc.
             515 Harmon Street
           Indianapolis, Indiana 46225
             Grant No. S803358
          Program Element No. 1BV610
         EPA Project Officer: Norman Plaks

      Industrial Environmental Research Laboratory
        Office of Energy, Minerals, and Industry
         Research Triangle Park, N.C. 27711
               Prepared for

      U.S. ENVIRONMENTAL PROTECTION AGENCY
        Office of Research and Development
            Washington, D.C. 20460

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                             TABLE OF CONTENTS
Figures    	   iv
Tables     	    v
Acknowledgments  	   vi

Section

   1      Introduction 	    1
   2      Conclusions  	    4
   3      Recommendations  	    5
   4      Proposed Process Summary 	    6
   5      Proposed Process Description   	    8

          5.1  Acid Recovery System and Ferrous Sulfate
               Heptahydrate Production 	    8
          5.2  Ion Exchange	   12
               5.2.1  Introduction	   12
               5.2.2  Proposed Production Plant  	   13
               5.2.3  Flow Rates in the Ion Exchange Unit  ...   17
               5.2.4  Operation of the Unit	   17
          5.3  Oxidation Unit	   19
          5.4  Hydrolysis (see Experimental Work)  	   19
          5.5  Solid-Liquid Separation 	   19
          5.6  Drying	   19
          5.7  Plant Costs	   19
   6      Experimental Work	   23

          6.1  Ion Exchange	   23
               6.1.1  Operation of Unit and Sampling	   23
               6.1.2  Loading Conditions and Preparation of
                      Sulfuric Acid  	   27
               6.1.3  Stripping Conditions   	   31
               6.1.4  Resin Capacity and Stability 	   39

          6.2  Oxidation Tower	   40
          6.3  Hydrolysis	   40

   7      Analytical Methods 	   46
   8      Preliminary Market Analysis  	   47
          8.1  Introduction	   47
          8.2  Iron Oxide Pigment Sales  	   48
          8.3  Technology	   51
   9      References  .	   54
                                    ii i

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                             LIST OF FIGURES
Number                                                           Page
  1        Distribution of steel  finishing plants   	     2
  2        Proposed process schematic  	     7
  3        Schematic of low temperature crystallizer 	     9
  4        Solubility of ferrous  sulfate in various  sulfuric
           acid concentrations	    11
  5        Schematic of double loop contactor resin:   Dowex
           HGR-W, 500 cu. ft. (14.16 cu m)	    14
  6A      Schematic of pilot plant contactor operated for
           concentrated nitrate  product 	    15
  6B      Schematic of pilot plant contactor resin:
           operated for concentrated HLSO*	  ,    16
  7        H2SO. - normality versus percent by weight  	    28
  8        Loading profile code:   30-34  	    29
  9        Loading profile code:   35-38  	    30
 10        Loading profile code:   59-62  	    32
 11        Loading profile code:   63-65  	    33
 12        Degree of stripping relative to excess  nitric  acid   .    34
 13        Strip profile code: 7-12	    35
 14        Strip profile code: 52-55  	    36
 15        Strip profile code: 56-58  	    37
 16        Laboratory hydrolyzer  300 ml  capacity   	    42
 17        Continuous coil hydrolyzer	    44
                                    IV

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                              LIST OF TABLES
Number                                                       Page
  1        Solubility of Ferrous Sulfate Heptahydrate
           in Sulfuric Acid Solutions	     10
  2        Capital and Operating Costs of Full-Scale
           Crown Acid Recovery System, Ion Exchange
           System, and Hydrolyzer to Produce Ferric
           Oxide	     20
  3        Capital and Operating Costs (Ion Exchange
           Only)	     21
  4        Daily Average Flow Rates - ml/min  	     24
  5        Daily Average Analysis of Inlet Streams  ....     25
  6        Daily Average Analysis - Exit Streams  	     26
  7        Iron on Stripped Resin	     38
  8        Nitrate Material Balance Before and After Use
           of Oxidation Recovery Tower 	     41
  9        Final Continuous Hydrolyzer Test Report  ....     45
 10        Finished Iron Oxide Pigments Sold by Processors
           in the United States, By Kind	     49
 11        Salient Iron Oxide Pigments Statistics in the
           the United States   	     50
 12        Producers of Iron Oxide Pigments in the
           United States in 1975	     52

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                              ACKNOWLEDGMENTS
     The authors would like to acknowledge the following people for
their help and advice in completing this project:  Mr. George Cable,
Manager, Quality Assurance, Pfizer, Inc., East St.  Louis, Illinois, and
Mr. Herb Gish, 3M Company, St. Paul, Minnesota.  Particular appreciation
is acknowledged to the following U. S. Environmental Protection Agency
personnel:  Dr. Herb Skovronek, Richard Tabakin, and John Ciancia at the
Industrial Environmental Research Laboratory in Edison, New Jersey, and
Norman Plaks, Chief, Metallurgical Processes Branch, Industrial Environ-
mental Research Laboratory, Research Triangle Park, North Carolina.
We wish also to acknowledge the Research Triangle Institute, Research
Triangle Park, North Carolina, for their assistance in preparing this
report.
                                    VI

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                                 SECTION 1
                               INTRODUCTION

     The problem of the disposal of spent pickle liquor (acid plus iron
salts) is widespread throughout the metalworking industry.   It results
from a great percentage of metal-surface-cleaning treatments.  Operations
such as cold rolling, wire drawing, galvanizing, tin-plating, and ex-
trusion are among these.  Figure 1 shows the geographical  distribution
of metalworking plants with 20 or more employees which normally use acid
pickling as a surface-cleaning method.  A recent EPA publication [1]
estimates well in excess of 100 major pickling locations.
     The disposal of effluent from these plants poses a serious problem
in maintaining the water quality in plant areas.  Current methods for
the disposal of pickle liquor include neutralization, pumping into deep
wells, removal to remote land areas, and deep sea disposal.  All of
these methods cause change in the surrounding environment.
     Recently, attempts have been made to develop sophisticated acid
recovery systems to enable metalworking firms to recover some waste acid
and alleviate the pollution problem.
     Systems currently exist and are in operation to regenerate HC1 by
roasting.  Reports indicate that these and other "noncatalyst-using"
systems consume excessive energy and are high in capital cost.
     There also exist systems for removal of ferrous sulfate from
sulfuric acid pickle liquors by low temperature crystallization.  One
such system is described in the Process Description section of this
report.  This system is relatively low in cost and energy requirements.
     However, in many areas of the country ferrous sulfate  is in over-
supply and is not a salable product.  Its possible disposal as landfill
is questionable.

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                                                                                                                          NEW ENGLAND
                                                                                                                          SR 5,  WD-28,
                                                                                                                          CR 14, PT-2,
                                                                                                                             G21
  PACIFIC
SR-15.WD-8.
CR-7, P7-24,
  G-22
                                                                                                                     MIDDLE
                                                                                                                     ATLANTIC
                                                                                                                     SR 55, WO-22
                                                                                                                     CR-26JJT-43,
                                                                                                                          36
                                            WEST WORTH CENTRAL
                                                SR-3.V1/D-0, CR-0
                                                   PT-11,G-9
EAST NORTH CENTRAL
    SR-56.WD-25,
     CR-39, PT-5
        G-69
                         MOUNTAIN
                       SR-3, WD-0, CR-0
                           PT-3. G-6
                                                                                                 EAST SOUTH
                                                                                                 CENTRAL
                                                                                                 SR-11,
                                                                                                 WD-1,
                                                                                                 CR-0,
                                                                                                 PT-7,
                                                                                                 G-7
                                            WEST SOUTH CENTRAL
                                                 SR-7,
                                                 WD-2.
                                                 CR-0,
                                                 PT-12,
                                                 G-7
                     SOUTH ATLANTIC
                     SR-14^
                     WD-6,
                     CR-2,
                     PT-4;
                      :7
                Legend
SR - Steel Works & Rolling Mills
WD - Steel Wire Drawing & Nails, not integrated
CR - Cold Steel Finishing Mills, not integrated
PT - Steel Pipe & Tube, not integrated
 G - Galvanizing & Other Coating
                                                 FIGURE 1. DISTRIBUTION OF STEEL FINISHING PLANTS

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     The process described in this report is a closed loop system in
which:
     1)   Sulfuric acid is returned to the pickling process,
     2)   Marketable ferric oxide is produced.
     The process offers the possibility of converting pollution control
from a nonproductive expense to a lower cost or, perhaps, a profitable
operation.
     The objective of this project was to explore the technical and
economic feasibility of the process.
     The two most important technologies needing investigation were:
     1)   Ion Exchange,
     2)   Hydrolysis.
     Therefore, experimental work was mainly limited to these two unit
operations.

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                                 SECTION 2
                                CONCLUSIONS
     The work reported establishes the feasibility of an ion exchange-
hydrolysis system to produce Fe^Og from FeSO  7^0.
     The proposed crystallization, ion exchange, oxidation, hydrolysis
process offers a complete recycle treatment for the treatment of waste
pickle liquor.  It also offers the possibility of relieving a serious
environmental pollution control problem.  The production of probably
marketable ferric oxide, offsetting the cost of waste treatment, is an
attractive feature.  However, a firm value for the product has  not been
established.  It probably lies in the range of $0.10-$0.80 per kilogram.
     Other technologies in the steel industry are beginning to produce
an iron oxide product.  The effect of these products on the future
market has not been assessed.
     The fact that the ion exchange and the hydrolyzer work were carried
out in separate locations is not of as great importance as might appear
at first glance since they are quite separate unit operations.
     A more serious problem is that a double loop ion exchanger has not
been built, although there is no reason it would not operate as proposed.
     Some plugging problems occurred with the continuous coil hydrolyzer.
Occasionally, nitrogen dioxide was observed.

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                            SECTION 3
                         RECOMMENDATIONS
It is recommended that:
1)   Further pilot scale hydrolysis work be done with the objective
     of continuous production of ferric oxide to determine baseline
     data on production rates and costs.
2)   A pilot plant be built with a double loop ion exchange unit
     and a hydrolyzer operating continuously on the same level.
3)   An engineering analysis be made to establish specifications
     for all units including auxiliary equipment such as oxidation
     towers, scrubbers, pressure letdown vessels, centrifuging
     equipment, dryer, pumps, piping, instruments, product storage,
     and bagging.
4)   A combined market research, technology assessment be made.
     The objectives would be to establish the market value of the
     typical ferric oxide product, establish the market value of
     products from reported competing technologies for waste pickle
     liquor treatment, evaluate comparative process economics and
     assess the impact on the market of emerging new products, and
     recommend the best system to industry.
5)   A demonstration plant be considered.

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                                 SECTION 4
                         PROPOSED PROCESS SUMMARY

     The initial step is a low-temperature crystallization of ferrous
sulfate heptahydrate from waste sulfuric acid pickling liquid.  The
recovered sulfuric acid is recycled to the pickling process.
     The ferrous sulfate heptahydrate is redissolved and introduced into
an ion exchange column and contacted with a cationic exchange resin.
Ferrous ions are absorbed on the resin and hydrogen ions are released to
yield approximately 15 percent by weight HpSO, for recycling to the
pickling process.  The resin is then regenerated with concentrated
nitric acid, and a solution of iron nitrate is produced.
     The nitrate solution containing ferrous and ferric ions, excess
nitric acid, and some byproduct nitrogen dioxide are passed through an
oxidizing tower to oxidize the N02 back to nitric acid and complete the
conversion to ferric ion.
     The resulting ferric nitrate, nitric acid solution is then passed
through a continuous coil hydrolyzer at about 205C to convert the
ferric nitrate to ferric oxide.  The solid ferric oxide is separated
from the nitric acid solution and dried.  The recovered nitric acid is
recycled to the ion exchange column.
     A schematic of the proposed plant is shown in Figure 2.
     Since the patent literature has not been searched, the present
patent situation is unknown.  The patentability of the process using
double loop ion exchange combined with the continuous coil hydrolyzer
should be determined.

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Crystallizer
                    Resin
                 I Recovery
                   Rinse
                   Water
                   2.5 M
                  FeSO,
1
Pu
c


r
np


ft
2
*
s



Rinse 	
Water
- Slip
^w
41V
HN
t
\ 
03
k
\
8
^

;



                                        H2S04
                                                                         Slip
                                                                         Water
                                                                         Fe(N03)2
                                                                         Fe(N03)3
                                                                         HN03
                                                                          N02

                                                                        Heat
                                                                      Exchanger
                                                       (2% Make-Up)
                                                                                              N2
             Packed
             Tower
                                                                                                Air
4 M HNO,
                                                                                          Dryer
                                                                                                        Fe203
                                               Hydrolyzer
                                                                                                                                                    Condenser
                                                                                                                                                      Discard
                                         Solid-Liquid
                                         Separation
                                                             FIGURE 2. PROPOSED PROCESS SCHEMATIC

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                                 SECTION 5
                       PROPOSED PROCESS DESCRIPTION

5.1  ACID RECOVERY SYSTEM AND FERROUS SULFATE HEPTAHYDRATE PRODUCTION
     Acid recovery systems for waste pickle liquors are commercially
available.  One such is the system marketed by Crown Environmental
Control Systems, Inc., a Division of Crown Chemical Co., Inc., of
Indianapolis, Indiana.  The Crown plant at the LaClede Steel Company in
Alton, Illinois, recovers approximately 76,000 liters (20,000 gallons)
per day of spent pickle liquor and produces 7.26 million kg (8,000 tons)
per year of ferrous sulfate heptahydrate.  A schematic plant diagram is
shown in Figure 3.  The process is based on the decreasing solubility of
the ferrous sulfate with decreasing temperature (see Table 1 and Figure
4).
     Waste acid is pumped from the Pickling Tank or the Storage Tank to
the Treating Tank and cooled to 32C with agitation.  The material from
the Treating Tank is then pumped to the Settling Tank.  There the material
is further cooled to approximately 0C.   After cooling, reclaimed acid
is pumped back to the Treatment Tank and then to a Storage Tank.  The
crystal slurry is pumped from the settling tank to the crystal storage
tank and from there to the tank car for shipment.
     Total operating and maintenance costs based on 300 days per year
of operations are:
System Batch Size
38,000 liters (10,000 gallons)
28,500 liters (7,500 gallons)
19,000 liters (5,000 gallons)
13,300 liters (3,500 gallons)
8 Hr./Day
$11,150
$ 8,500
$ 7,000
$ 6,000
24 Hr./Day
$23,500
$17,900
$14,000
$11,800
                                    8

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        RECLAIMED ACID

A


..


mf
i
src
B
\
nCbLHINICU
ACID _
*-
ACID-
CRYSTAL
SLURRY

rc
D

CRYSTAL
SLURRY

L
E
^
A  WASTE ACID STORAGE TANK    C 
B TREATMENT TANK            D
                     AGITATOR
                     SETTLING TANK
E  CRYSTAL STORAGE TANK
F  STORAGE TANK
FIGURE 3. SCHEMATIC OF LOW TEMPERATURE CRYSTALLIZER

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 TABLE 1.  SOLUBILITY OF FERROUS SULFATE HEPTAHYDRATE IN SULFURIC
           ACID SOLUTIONS

H2S04
%w/w*
2.5
5
7.5
10
12.5
15
20
25
30
35
40
45

32C
12.66
11.62
10.61
9.61
8.63
7.70
5.99
4.46
3.21
2.91
2.59
2.64
FeS04 %W/W*
25C
21.31
19.77
18.41
17.30
17.15
15.06
13.17
11.41
10.29
8.51



45C
29.34
27.76
26.37
25.52
24.65
23.22







*%weignt7total  weignt.
                                     10

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                                              PHASE CHANGE
15   , 12 .
12.5  . .
10   ..
 7.5  ..
 5
 2.5  . .
                                     104    122    140




                                       TEMPERATURE
158
176
194
212 F
          FIGURE 4. SOLUBILITY OF FERROUSSULFATE IN VARIOUS SULFURIC ACID CONCENTRATIONS
                                             11

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     An average analysis of the recovered ferrous sulfate'crystals is:
     FeS04   7H20   	     99.5%
     Sulfate        	     33.0%
     Water          	     45.5%
     Iron (Fe++)    	     21.0%
     Copper         	      0.005%
     Lead           	      0.03%
     Manganese      	      0.01%
     Tin            	      0.001%
     Zinc           	      0.01%
     Silicon        	      0.001%
     pH (of Slurry)	      1.2
     Since such commercial systems for ferrous sulfate crystals exist,
no experimental work was done.  Commercial crystals were used as feed.
5.2  ION EXCHANGE
5.2.1  Introduction
       The proposed ion exchange process is based on a study made by the
Chemical Separations Corporation, Oak Ridge, Tennessee, for the U. S.
Federal Water Pollution Control Administration [2].  A number of per-
tinent patents were issued to I. R. Higgins as a result, including
these:
     U. S. Patent 3,470,022, Process and Apparatus for Process
          Pickling Liquor, and
     U. S. Patent 3,468,707, Hydrolyzer Process for Steel  Pickling
          Liquors.
     It is reported that the double loop ion exchange process proposed
herein is covered by U. S. Patent 3,677,937 [3].
                                    12

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     The process chemistry may be represented by the following equations:

          a.   Ion Exchange Loading
               FeS04 + 2H-R
          b.   Ion Exchange Regeneration

                  X
               Fe<^R + 2HN03 * 2 H-R + Fe(N03)2

          c.   Oxidation from Ferrous to Ferric Ion
               Fe++ + 2H+ + N03  +  Fe+++
          d.   Nitrogen Dioxide Oxidation (in oxidation unit)
               2N02 + H20 + 1/2 02 * 2HN03
5.2.2  Proposed Production Plant
       The use of double loop countercurrent flow is well suited to the
process in which the concentration of both the sulfuric acid and ferrous
nitrate products must be maximized and tons of products per day are to
be produced.
     It is proposed to build a double loop countercurrent 1on exchange
contactor designed for the production of 5,442 kg (6 tons) per day of
ferric oxide.  A schematic drawing of the unit 1s shown in Figure 5.
However, it should be noted that all of the experimental work 1n this
study was carried out in a single loop contactor such as shown 1n
Figures 6A and 6B.  No commercial double loop unit exists at present.
                                    13

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         .r
        Resin
        Trap
                Rinse
                     ?
                  Pulse   I
                      2.4m
Top View
              FeS
O  O
o  o
             1
                   *-h
            3.6 m     l.g
             j
                         .Sir
                             Pulse
                             Cond.
                             Control
                                        Rinse
                                       -*-
                                         Slip
                                         Water
 Cond.
'Control
                                        HN0
?*
                                                Cond.
                                                Control
                               1.5m

                                A
                                                   B
                                                         t
                                                        KB
                                                         14,
                                                            iackwas!)
                                                                Slip
                                                               Water
                       Cond.
                       Control
                         Fe(N03)3
                         Fe(N03)2
                         N02
                         HN0
                                                                               Fe
                    FIGURE S. SCHEMATIC OF DOUBLE LOOP CONTACTOR
                            RESIN: OOWEXHGR-W.SOOcu.ft.
                                         14

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     H2S04
Strip Rinse
                                                              Air
Ft
-------
1 .,


X' *


Strip Rinse v

1.2m

4M HN03 < |___
Strip


Product 2.4m
Fe(N03)3
* Fe(N03)2
Fe(NOi)
6(33 N02 
HNO. - V


V '
Y
0.6m
. -t
f O.ttm
j
1 	 3L_
Air *
(Urn
/

^^

4



I







X

1


/

i
s

SR-1
, Cond.
Control


^.S-1 1
H-





2

-X.FR-I
Cond.
^ Control
^~ FR-2
V >
1

X

1
T
"XI





.2m






4m




t
j
Resin
Train
i rap
Backwash \. .S
^*
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     The unit will be 0.915 m (3 ft) in diameter and contain 14,150
              3                                        i '    '  '    i C . ...
liters (500 ft ) of a cation exchange resin such as Dow HGR-W (a gel
type resin).   The unit will be fabricated from stainless steel.
5.2.3  Flow Rates in the Ion Exchange Unit
       The feed is 16 liters/min (5 gallons/min) of approximately 2.5
Molar or 5 Normal ferrous sulfate heptahydrate (FeSO^  7H20) at 60C.
Only two runs were made at the proposed operating temperature of
approximately 60C after it was learned that 18 percent sulfuric acid
was desirable.  All others were run at 20C.  The design  exchange
capacity of the resin is 1.5 equivalents ("eq") of Fe   per liter of
resin.  Consequently, the feed to resin flow ratio is
                         1.5 eg/1 resin
                         5 eq/1  Fe
or 0.3 and the resin flow rate is approximately 64.5 liters (17 gallons)
per minute.  A 75-percent excess of 4M nitric acid for stripping the
iron from the resin is assumed, based on ferrous ion with a flow of
about 41.8 liters (11 gallons) per minute
                         4 eq/1 x 41.8 1     ,  7,
                       ,1.5 eq/1 x 64.5 1   ~ lo/t>l
It is assumed that the nitric acid regenerant will  contain about 1
percent iron upon recycle from the hydrolysis unit.
5.2.4  Operation of the Unit
       The ferrous sulfate solution is introduced into the left-hand
part of the unit, as shown in Figure 5.   It flows downward through  a
portion of the hydrogen ion loaded resin bed in the  section of the  unit
labelled A in Figure 5.
                                    17

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     Simultaneously, regenerated H^SO* is withdrawn from the right-hand
arm of A as shown in Figure 5.
     Similarly, a portion of the resin loaded with ferrous ions is
treated in part B of the unit with 4 Molar nitric acid, and the ferrous
ions on the resin are replaced by hydrogen ions.   The resulting product
consisting of FeCNOOos FeCNO-Joj some NOo, and HNOo is drawn off.
     Rinse water for the ferrous ion loaded resin flows intermittently
in A, the flow being controlled by a conductivity probe ("cond." in
Figure 5) which serves to maintain the ferrous sulfate solution, water
interface at a constant level.  When on, the interface is displaced
downward; when off, upward.
     The H-resin above the sulfuric acid contains water in its void
spaces (having been rinsed in B).  When the rinse water is on, sulfuric
acid flows if its exit valve is open.  If it is closed, the slip cycle
valve is open.  Which valve is open is controlled by the conductivity
probe at the sulfuric acid, water interface.  When the slip cycle valve
is open, the sulfuric acid displaces the H-resin water which flows out
the slip cycle valve.  This slip cycle water can be recycled.  Its
volume is equal to that of the rinse water, discounting a small dilution
of the HpSCL product.  It contains only a small amount of acid or
mineral ions.  A similar rinse process occurs in B for the hydrogen ion
loaded resin.
     The flows of ferrous sulfate and nitric acid in A or B, respectively
are shut off and the resin beds are pulsed or shifted countercurrently.
The valve above each rinse cycle is open while the resin is being pulsed.
The rate of resin flow is determined by the feed/resin flow ratio dis-
cussed previously.
     In A, a portion of the ferrous ion laden resin (Fe-R), with its
void space containing water, flows overhead to the resin trap on the
right (Fe-Resin Trap) to be fed to B.  From B, a portion of the hydrogen
laden resin flows to the resin trap on the left (H-Resin Trap), to be
fed to A.
     The overall process is repeated in short cycles.
                                    18

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5.3  OXIDATION UNIT
     It is planned to heat the nitrate product from the ion exchange
unit to 95C before passing the product into a 10.16-cm (4-inch) diameter
packed tower, 3.05 m (10 ft) high.  Air will be blown through the tower
                        o
at 10,613 liters (375 ft ) per minute to oxidize ferrous ion and any
nitrogen dioxide.
5.4  HYDROLYSIS (See Experimental Work)
     A scraped coil continuous hydrolyzer will be used.  The process
design requirements will be determined from the experimental work re-
ported.  No analysis of the availability of suitable commercial equipment
has been made yet.
5.5  SOLID-LIQUID SEPARATION
     No work has been done to investigate the separation of the liquid
HNOg and solid FegO^ coming from the hydrolyzer.  It is felt that commercial
equipment can be specified.
5.6  DRYING
     No specifications for the drying step have been established.
5.7  PLANT COSTS
     Very preliminary plant cost estimates have been made.   They are
shown in Tables 2 and 3.  The estimates have been made by knowledgeable
engineers. However, the availability and cost of commercial equipment or
equipment design and construction cost would have to be firmed up con-
siderably before a demonstration plant could be built.
     The estimated total capital cost of the plant Installed is $1,285,000.
     The yearly operating costs (for 350 days) are estimated at $91,000.
     The costs of the complete plant cover:
     1)   the acid recovery system,
     2)   the ion exchange system,
     3)   the hydrolyzer system.
                                    19

-------
                 TABLE 2.   CAPITAL  AND  OPERATING COSTS OF FULL-SCALE CROWN ACID RECOVERY SYSTEM,
                                ION EXCHANGE SYSTEM, AND HYDROLYZER TO PRODUCE FERRIC OXIDE
            	(BASIS:   76,000  liters (20,000 gallons/day) of waste sulfuric acid)	

                                                 CAPITAL COSTS
             Equipment      	    $950,000.00
             Installation    	    $175,000.00
             Engineering    	    $ 90,000,00
             Building       	    $ 70,000.00
                                       TOTAL INSTALLED COSTS   	  $1,285,000.00
r
-------
                          TABLE 3.  CAPITAL AND OPERATING COSTS (ION EXCHANGE ONLY)
                                                  CAPITAL COSTS
             Chem-seps CCIX Contactor    	  $350,000.00
             Installation                	  $ 50,000.00
             Start-Up                    	  $ 50,000.00
                                                                                            $450,000.00
                                                OPERATING COSTS
~"                                                                                          (Dollars/day)

             Resin  attrition  -  3 years @$40/cu. ft. (28.3 liters)    	                 20
             Nitric acid make-up @  2%, @$80/ton (907  kg)	                 27
             One operator/shift, plus supervision
              @$5/hr	                120
             Maintenance(Material  & Labor)
              @5% of equipment  without exchange resin 	                 45
             Power     50 hp @ 2
-------
     It is assumed that one operator per shift can operate the total
plant.  The plant would require 12 to 16 months to build and install.
However, if the proposed demonstration plant could be located at the
site of an existing low-temperature acid recovery plant, the estimated
cost would be significantly reduced.

-------
                                 SECTION 6
                             EXPERIMENTAL WORK

6.1  ION EXCHANGE
6.1.1  Operation of Unit and Sampling
       As noted, all of the experimental work was carried out in the
single loop pilot plant equipment operated as shown in Figures 6A and
6B.
     Studies aimed at the production of concentrated iron nitrate used
the arrangement of Figure 6A, and those emphasizing the production of
concentrated H^SO, used the arrangement of Figure 6B.
     The pilot plant unit is operated in essentially the same manner as
that described in detail for the proposed double loop unit.   However,
there is an important difference.  The rinse section lies between the
two product solutions which are desired at a high concentration (or
density).
     Therefore, when operating as shown in Figure 6A,  there is a much
greater possibility for dilution of the sulfuric acid  product than when
operating as in Figure 6B for the dilution of the nitrate product.  This
is so since resin in which the void spaces are filled  with water passes
through the zone where the product above it is drawn off.  This is the
major reason for the proposed double loop unit.
     The flow rates and analyses for the runs of this  section are given
in Tables 4, 5, and 6.
     The unit was operated at steady-state flow conditions over a daily
shift period.
     Samples of the effluent products are taken each hour in order to
get a material balance and an average analysis.
     Near the end of the day, samples (called profile  samples) are taken
around the loop.
     Profile samples are taken consecutively at 0.61-m (2-foot) intervals
downstream from the point of solution entry, as indicated in Figures 6A
and 6B.

                                    23

-------
                                   TABLE 4.   DAILY  AVERAGE FLOW RATES -ml/min
ro
Code
5-8
9-12
13-17
18-21
22-27
30-34
35-38
39-41
42-46
48-51
52-55

56-58

59-62
63-65
Feed
(FeS04)
396
330
264
166
220
231
186
165
165
209
188

176

132
110
Product
(H2S04)
1390
1140
930
860
720
208
200
125
416
402
450

391

140
78
1 Strip
1 (HN03)
279
330
300
340
705
310
325
290
371
324
310

424

382
387
Product
(Fe(N03)2
(Fe(NOa)3
(HNOa)
408
341
296
316
342
325
317
380
367
325
350

441

408
417
1
Product
Slip
Water
241
275
374
316
292
250
291
250
241
304
275

250

250
233
Resin
400
400
400
400
400
400
400
400
400
400
400

400

400
400
Remarks
Figure 2A




Figure 2B

Figure 2A


80% Fresh Acid
20% Recyle
Product Acid
60% Fresh Acid
40% Recycle
Product Acid
Heated Feed
No Rinse -- Heated Feed

-------
TABLE 5.  DAILY AVERAGE ANALYSIS OF INLET STREAMS
Code
5-8
9-12
1 3-1 7
18-21
22-27
28-29
30-34
35-38
39-41
42-46
48-51
52-55
56-58
59-62
63-65
Feed
H
FeS04
2.82
2.82
2.80
2.80
2.99
2.99
2.99
2.99
2.82
2.73
2.70
2.90
2.90
4.62
4.62
Fell
9/1
76
76
--
--
75
75
75
75
80

--
85.5
85.5
133
133
Strip
4-
H FeUI
NI g/1
4.10
4.10
3.84
3.91
3.93
3.99
4.00
4.00
4.00
4.0
3.7
3.67 7.0
3.70 14.2
4.0
3.77 "
                          25

-------
TABLE 6.  DAILY AVERAGE ANALYSIS - EXIT STREAMS
Code
5-8
9-12
13-17
18-21
22-27
30-34
35-38
39-41
42-46
48-51
52-55
56-58
59-62
63-65
Nitrate
Product
TM+H
eq/1
2.34
3.42
3.31
3.50
3.80
3.14
3.59
3.10
3.54
3.18
3.47
3.44
3.77
3.59
Fe
9/1
31.7
70.5
54.0
79.0
29.0
27.0
58.0
31.0
25.0
57.3
44.3
39.0
41.5
39.5
N03
9/1
125
198
190
T80
230
150
210
140
175
183
165
158
215
340
H2S04
Product
TM+H
eq/1
0.83
1.03
0.97
0.63
1.00
2.54
2.57
0.51
1.24
1.80
1.34
1.33
2.12
3.29
Fe
9/1
2.7
10.2
15.8
8.5
2.7
12.6
7.5
0.8
3.6
7.0
6.5
11.1
10.8
12.5
N03
9/1
9.0
5.8
0.95
6.5
1.6
6.6
17.0
1.3
2.7
26.0
6.2
2.8
9.8
4.3
Slip
Water
H+
eq/1
__
	
	
	

	
0.45
0.08
0.05
0.04
0.05
0.06
0.09
0.07
Fe
g/i
4
0.64
2.4
2.4
1.1
0.4
0.78
29
0.68

0.05
0.08
0.75
0.04
N03
g/i
0.10
0.03
2.0
2.5
2.0
1.9
3.1
5.0
2.7
0.8
0.15
0.33
1.3
0.3
                        26

-------
6.1.2  Loading Conditions and Preparation of Sulfuric Acid
       In most of the runs reported herein, a tank of saturated FeSO,
solution at 20C was used as feed.  Under these conditions, the feed was
about 2.8N.  Therefore, the HpSO* product could not be greater than 13
percent (see Figure 7).
     The results under these conditions of the two successfulruns to
maximize hUSO. concentrations are shown in Figures 8 and 9, and in
Tables 4, 5, and 6, Code Numbers 30-34 and 35-38.
     For example, see Figure 9.  Samples of the product are taken at F-l,
F-2, and F-3 and at the H2$04 exit valve (0.61-m (2-foot) intervals) in
Figure 6B. These samples are analyzed for SO^ by the Total Mineral
(T.M.) method and for iron by the ortho-phenanthroline method (see the
Analytical Methods Section).
     The product, from the curve, is about 2.5N in SOT concentration,
equivalent to about 11.5 percent by weight H2S04.  The dilution of the
3N 507 feed to 2.5N S07 product by the slip water is obvious.  The iron
content of the product is low, it generally being of the order of 10
percent by weight of the H2S04.
     It is postulated by the authors that some oxidation of the ferrous
ion by HN03 occurs during the stripping or resin regeneration step.
Subsequent hydrolysis leads to the formation of a species of Fe203
which is insoluble in HN03 and which is occluded in the resin matrix.
This Fe203 is carried around the loop in the matrix of the resin and is
dissolved by the strong H2S04 product, thus accounting for the iron in
the HpSO. product.
     It was learned by Crown during these studies that an 18 percent by
weight H2$04 product was desirable.  In order to avoid the use of an
evaporation step, two attempts were made to make a stronger product by
heating the FeS04 feed tank with a stainless steel coil to 60-65C
with agitation.  Between 60 and 80C, FeSO^ has a limiting solubility
of about 6.6N.  The conditions used were a temperature of 62C and a
concentration of FeS04 of 4.62N.  These conditions are close to the
proposed plant conditions.  The runs were made so as to maximize nitrate
product.
                                 27

-------
ro
CO
                NORMALITY

                H2S04
                                                                      10
                                                                  WEIGHT PERCENT H2S04
15
20
                                              FIGURE?. H2$04 - NORMALITY VERSUS PERCENT BY WEIGHT

-------
               NORMALITY
r>o
10
         FEED - 2.99 NORMALITY FeS04
      FEED/RESIN FLOW RATE RATIO = 0.58
           AMBIENT TEMPERATURE
                                                                               SO,
                                FEET      1
                                METERS   0.3
2
03
 3
0.9
4
1.2
 5
1.5
6
1.8
7
2.1
8
2.4
                                                        FIGURE!. LOADING PROFILE CODE: 30-34

-------
                                                             FEED - 2.99 NORMALITY FeS04
                                                          FEED/RESIN FLOW RATE RATIO = 0.47
                                                              AMBIENT TEMPERATURE
                   NORMALITY
                            5  _
co
o
                               FEET       1
                               METERS   0.3
2
0.6
 3
8.9
 4
1.2
5
1.5
6
1.8
7
2.1
8
2.4
                                                         FIGURE 9. LOADING PROFILE CODE: 35-38

-------
     The results obtained are shown in Figures 10 and 11  and Tables 4,
5, and 6, Code Numbers 59-62 and 63-65 with Run 63-65 producing about 15
percent H^SO,.  The iron concentration drops very rapidly along the
resin bed, as can be seen in Figures 10 and 11, showing a high rate of
exchange with the resin.  This is probably due to the higher temperature.
6.1.3  Stripping Conditions
       It is desirable to use the minimum excess HN03 required to leave
a minimum of unstripped iron on the resin.  There is a limit to the
extent of iron removal regardless of the amount of HNO^ used.
     This is shown by the data for 10 runs in which the amount of iron
remaining on the resin after stripping was determined.  The procedure
used was to complete the removal of the iron by stripping the regenerated
resin with H^SO* or HC1 and determining the removed iron by the ortho-
phenanthroline method.  In all of the runs, the concentration of the
HMO, was approximately the same (4M) as was the FeSOA/resin flow ratio.
   *5                                                T"
The data are summarized in Figure 12 and Table 7.  Analysis of the
experimental points shows little or no difference between the amount of
iron retained on the resin between an excess of HN03 of 50 percent and
150 percent.
     The strip profiles of Figures 13, 14, and 15 show typical events of
the stripping process.  Note that the normality of the replaced iron
solution cannot be greater than the normality of the stripping acid.
Referring to Figure 13, for example, it is seen that the stripping
acid/resin flow rate is 0.83.  Therefore 3.4 equivalents of HNOo have
                                            ++
replaced approximately 2.5 equivalents of Fe   at the 2.4-m (8-foot)
product exit of the column.  Therefore, we have an excess of 36 percent
HN03 (3.4/2.5 = 1.36 or 136 percent) based on ferrous ion.  The percent
excess HN03 cannot be determined exactly since both ferrous and ferric
iron are probably present.  Some attempt was made to determine the
fraction of Fe   and Fe    ions emerging from the ion exchange unit,
but the results varied from 50 to 90 percent oxidation.   Therefore,
it is necessary to use an oxidation tower for this reason as well as to
oxidize N02.
     There is a slight dilution of the total nitrate near the product
exit. This is due to dilution by the slip water.  However, the nitrate
strength is easily made up during the blowdown from the hydrolyzer.

                                    31

-------
            NORMALITY   5
OJ
ro
                              FEET       1
                              METERS    0.3
2
0,6
                                                                  FEED/RESIN =0.33
                                                             FEED  4.62 NORMALITY FeS04
                                                                       62 C
                                                                   LR = 65.6 g/l Fe
                                                                   SR = 16.0 s/l Fe
4

1.2
5

1.S
6

U
7

2.1
8

2.4
                                                        FIGURE 10. LOADING PROFILE CODE: 59-62

-------
             NORMALITY
CO
OJ
                         2   L
                                           FEED/RESIN = 0.28
                                      FEED -4.62 NORMALITY FeS04
                                                 62 C
                                             LR = 59.2 g/l Fe
                                             SR = 16.0 g/l Fe

                                                   SO,
                                                              _L
FEET      *          2
METERS   0.3         1.6
                                                              8J         1.2         1J

                                                               FIGURE 11. LOADING PROFILE CODE:

-------
30
                      EACH POINT REPRESENTS A DAILY STEADY-STATE RUN
25
20
15
10
              25
50
75
100        125        150        175
                        PERCENT EXCESS HNOj BASED ON FERROUS IRON
                                                                                       200
                FIG URE12. DEGREE OF JTRJFFUIG RELATIVE TO EXCESS. UPTfttC ACID

-------
oo
in
         NORMALITY
                                X EXCESS HN03
                               BASED ON Fe
                               BASED ON Fe
36%
= 0%
                        FEfT    -  -1 .
                        METERS    13
                                                            STRIP-4.18 MHN03
                                                        STRIP/RESIN FLOW RATIO = 0.83
                                                           SR = 9.0 9/1 Fe
            s
            u
1.6
2.1
2.4
                                                      FIGURE 13. STRIP PROFILE  CODE: 7-12

-------
         NORMALITY
CO
CTi
                                                          STRIP - 3.67 M HNO+ - 7 g/l Fa***
                                                          STRIP/RESIN FLOW RATIO = 0.78
                                                            SR = 19.2 |/l Ft
                                 % EXCESS HN03
                              BASED ON Fe^-120%
                              BASED ON Fe""*- 45%
                                                                              Ffl AS Fe
                                                                                                                  I
                         FEET       1
                         METERS   1.3
2
M
 3
0.1
4
U
s
1.S

1.1
7
2.1
8
2.4
                                                     FIGURE 14. STRr PROFILE CODE: 52-55

-------
                NORMALITY
CO
-4
                                            X EXCESS HN03
                                          BASED ON Ft" - 149%
                                          BASED ON Fe+++-65S
                   STRIP - 3.7 M HN03 -14.21/1 ft"
                   STRIP/RESIN FLOW RATIO -1.06
                        SR = 14.0 |/l Ft
                                   FEET
                                   METERS
1
OJ
                                                           NO,
                                                           FiASFt***
2
M
3
M
S
1.1
I
1.1
7
2.1
8
2.4
                                                             FIGURE 15. STRIP PROFILE CODE: SMI

-------
TABLE 7.  IRON ON STRIPPED RESIN
Code
9-12
13-17
18-21
22-27
30-34
48-51
52-55
56-58
59-62
63-65
% Excess
Nitric Acid
36
59
24
220
212
56
120
149
156
156
HN03
Concentration
4.10
3.84
3.91
3.93
4.00
3.70
3.67
3.70
4.00
3.77
1
1 g/1 Iron on
i Stripped Resin
1 9.0
| 16.8
| 20.8
| 6.5
| 12.6
I 14.4
| 19.2
I 14.0
I 16.0
I 16.0
1
HN03/resin
Flow Ratio
0.83
0.75
0.85
0.76
0.93
0.81
0.78
1.06
0.96
1.04
               38

-------
     In the runs where the strip nitric acid was a  simulated  hydrolysis
product (Figures 14 and 15), the effect is a tailing of iron at the
0.61-m (2-foot) mark.
     The accuracy of the analyses and measurements of Sections 2 and 3
as well as the efficiency of the process is shown by the data of Tables
4, 5, and 6.
     For example, consider the run of Code 59-62.  This is a warmed
(62C) run to maximize iron nitrate production.
     The feed is 0.132 1/min of 4.62N FeSO^ or 0.61 eq/min, equal to
17.1 g/min of iron.
     The product is obtained at 0.408 1/min at a concentration of 41.5
g/1 of iron.  Therefore, 17.0 g/min are produced.
     The slip water flows at a rate of 250 ml/min and contains 0.75 g/1.
Therefore, 0.19 g/min pass in the slip water.  The material balances are
excellent.
6.1.4  Resin Capacity and Stability
       A cost factor of major concern is related to the stability of the
resin.  In a previous study [2], fixed beds of new resin and resin used
for approximately 6 months were loaded rapidly with dilute FeSO, solution.
The ion exchange capacity measured from both loading and stripping was
about the same (1.75 eq/1).  The rate of exchange was actually a little
faster on the used resin.
     A sample of the used resin was sent to the Dow Chemical  Company for
evaluation.  It was not out of specifications in any way compared to new
resin, as shown in the following analysis:
          H-form capacity - 2.06 eq/1
          Na-form capacity - 2.20 eq/1
          H-form 47% water (47% to 50% is standard)
          98% whole beads (1% broken beads)
     If extended studies show significant breakdown, alternative resins
are available.  However, at the moment, the life of the resin does not
seem to be an important factor.
                                    39

-------
6.2  OXIDATION TOWER
     In the oxidation of ferrous ion by nitric acid, nitrogen dioxide is
formed.  A small, packed column was used at the ion exchange product
outlet, and the nitrate product was heated and blown with air to oxidize
the N02 to HNOj and the ferrous to ferric ion.
     A nitrate ion selective electrode was used to follow nitrate material
balance (see Analytical Methods).  Nitrate material balances before and
after use of the packed tower are shown in Table 8.  Nitrate recovery is
nearly 100 percent when using the tower.
6.3  HYDROLYSIS
     The basis for this work is a patent owned by the Bethlehem Steel
Corporation [4].
     Ferric nitrate produced by the ion exchange unit is decomposed
thermally.  The nitric acid produced is returned to the ion exchange
unit for resin regeneration.  The ferric oxide produced may be an
attractive commercial product.
     The nitric acid, ferric nitrate liquors used were from Chemical
Separations Corporation work.  The initial experiments were conducted in
a 300 ml autoclave (see Figure 16).
      A thermocouple was installed within a sheath probing the autoclave
cavity.  It was connected to a -17.8C to 242C Honeywell Indicator.
      A second thermocouple was attached to the furnace and connected to
a -17.8 to 1025C Fenwall Controller in order to insure that the furnace
was not heated excessively.  The controller was set at 512.5C.  The
heat-up time for the contents of the lead-jacketed vessel was over 20
minutes.
      It was determined that the precipitate formed in the hydrolyzer
was ferric oxide and not ferric hydroxide.
      However, with this apparatus it could not be determined if the
conversion occurred within the liquid at 205C or at the vessel wall at
512.5C.
      Nitrogen dioxide was observed emerging from the discharge of the
pressure vessel.  Therefore, the process may require a scrubber or
oxidizer of some sort behind the hydrolyzer.
                                    40

-------
TABLE 8.  NITRATE MATERIAL BALANCE BEFORE AND AFTER USE OF
          OXIDATION RECOVERY TOWER
Code
5-8
9-12
13-17
18-21
22-27
28-29
30-34
35-38
39-41
42-46
48-51
52-55
56-58
59-62
63-65
Percent Recovered N03
70%
88
85
83
100
118
82
87
102
88
86
107
97
101
102
Remarks
Before use of
Tower






After Installation
of Tower







i










                           41

-------
             PRESSURE
TEMPERATURE
INDICATOR
THERMO COUPLE WELL
                                                             MOTOR
                                                              MAGNETIC COUPLING
                                                              (NO SHAFT SEAL)
COOLING COIL
                                                                          ELECTRIC HIATER
                                                                          311 STAWiEM STEEL
                                                                        ALL INTERNAL PARTS
                                                                   361.6 ki/cn2 (5,||g jfcfc.2) CAPACITY
                       FIGURE 16. LABORATORY HYDROLYZER 310 nri CAPACITY
                                                 42

-------
      To determine the lowest efficient hydrolysis temperature, a 3.8
liter (1 gallon) continuous coil  (1.6 cm (5/8 in.) - 316 stainless)
autoclave was constructed.  A schematic of the apparatus is shown in
Figure 17.  This coil was small enough in diameter to provide essentially
instantaneous heat up to the 205C of the Dowtherm constant temperature
bath.  The pressure differential of input and output determined the flow
rate.  At a rate below 7.6 liters (2 gallons) per hour,  the  tube  clogged.
At a rate much greater than 7.6 liters (2 gallons) per hour the con-
version to Fe203 was incomplete.
     Three hundred runs were conducted to convert ferric nitrate to
ferric oxide, 254 in the batch unit and 46 in the continuous unit.
     An average of 20 percent by weight HN03 was recovered in these
runs.
     The produced iron oxide contained adsorbed nitrates.  After drying
at 200C for 1 hour, about 99 percent Fe203 could be produced.  There is
no difference if the Fe203 product is dried at 550C.  However, it is
clear that a drying step will be necessary in the process.  An average
analysis of the best 20 successful continuous runs is given in Table 9.
The Fe203 has an average purity of 98.8 percent which 1s suitable for
pigment.  Analysis of the Fe203 was performed by Crown; Pfizer, Inc.;
and 0. A. Laboratories.
                                    43

-------
Item
1
2
3
4
5
6
7
8
9
Quantity
1
1
1
1
2
1
2
1
1
10
11
12
13
14
40'
40'
 1
 1
 1
     Description
Dry Nitrogen Tank
Nitrogen Prassun Regulator
Nitrogen Valve Set
Check Valve
Relief Verve
Ferric Nitrate Tank
Check Valves
Dowtherm Tank
4 KW Heating Ete.

Coil 1.6 cm (5/8 in.) Steel Tube
Con 0.6 cm (1/4 in.) 0.0. Tube
Gear Pump
Needle Valve
Flash Tank
                                                      Notes

                                             35.2 K|/cn2 (0-500 Ib/in.2)
      T
      P
 Presara Gauges
3U Kg/cm2 (500 Ib/in.2) 316 S.S.
49.2 Kg/cm2 (700 Ib/in.2) 316 S.S.
49.2 Kg/cm2 (700 Ib/in.2) 316 S.S.
49.2 Kg/cm2 (700 Ib/in.2) 316 S.S.
Steel
Hi Temp. Cut-out                         ''
Self-contained Stit - Q  371.1 C. (700 F.)    \
316S.S.
316 S.S.
Variable Speed Motor
316 S 260 C. (500* F.) 49.2 Kg/cm2 (700 Ib/in.2
316S.S.
                                                             FIGURE 17. CONTINUOUS COIL HYDROLYZER

-------
             TABLE 9.  FINAL CONTINUOUS HYDROLYZER TEST REPORT
                    SUMMARY OF 20 BEST SUCCESSFUL RUNS


AVERAGE INPUT 2000 ml      Fe(N03)3     Co11 Wal1 TemP-
 wflk*wwwMwMaawKM**wMBWB**n*v~*M*MHvaiMH


                      PRESSURE:
                                                               (205C)
CONTACT TIME:

  10 min
   ANALYSIS OF COMPOSITE SAMPLE

                 Fe23

   %Fe203        98.8


   Color         Red


Total Sample     20 g
                                        AVERAGE NITRIC ACID ANALYSIS
                                                  20.5 %HN0
                                                   1.5 %Fe

                                                  Yellow  Color
                                    45

-------
                                 SECTION 7
                            ANALYTICAL METHODS

     Acid concentrations were determined by standard acid-base titra-
tions.
     All iron was determined by the standard ortho-phenanthroline colori-
metric method [5].  In this method the ortho-phenanthroline is sensitive
only to the ferrous ion.  However, both ferrous and ferric ions may be
determined by leaving out or adding the hydroxylaniline-hydrochloride
reducing agent.  In this study a considerable number of inconsistencies
were observed, and it was not possible to determine accurately the
ferrous/ferric ion ratio at the contactor exit.  But for total iron,
the method is highly accurate.
     Nitrate ion was determined by using a Corning ion selective electro-
diode with a Model 404 Orion meter.  The method is sensitive and accurate.
It is important to check frequently with a standard.  Interferences are
well eliminated by setting the instrument to read low ppm levels (9-
100) and making large dilutions.
                                      LI      -It I
     Where acid (H2S04 or HN03) and Fe   or Fe    are present together,
a total mineral (acid and metal ions) analysis was made (T.M.).  The
solution is passed through a column of cation exchange resin.  The metal
ions are exchanged for hydrogen ion.  The resulting acid is titrated
with base.  The method is simple and accurate.  All free acid must be
rinsed from the column, and the resin cannot be overloaded with the iron
ions.
     Analyses of the Fe203 product were made by outside analytical
laboratories.
                                    46

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                                 SECTION 8
                        PRELIMINARY MARKET ANALYSIS

8.1  INTRODUCTION
     Crude iron oxide (FegOj or ferric oxide) exists in the natural
state as a mineral deposit.  It is also produced synthetically by
various chemical processes.  Purity, color, and many other character-
istics differ widely from source to source in both natural and manu-
factured materials.
     Processing companies convert these crude materials into finished
iron oxide by various operations such as washing to remove impurities,
grinding to a smaller particle size, blending for shading and color tone
or desired magnetic properties, weighing, packaging (usually 50-pound
(22.7 kg) paper bags), and identifying by marking of containers.
     The processors sell the finished iron oxide to manufacturers who
use it as a color pigment in their products.  They also sell finished
iron oxide to manufacturers of ferrites, who use the Fe20.j as raw
materials having ferromagnetic properties.
     Most finished iron oxide, whether for use as color pigment or
ferrite starting material, is the product of skillful blending by the
processors, who work very closely with their customers to satisfy indivi-
dual requirements.  This implies a high technical service ability.
     Based on a survey by the National Paint, Varnish, and Lacquer
Association and on a status report by Philips Laboratories on magnetic
ceramics (including those produced from ferrites), the end-use markets
for natural and synthetic iron oxides are estimated to be in the following
proportions.
     40% ferrite starting materials;
     40% color pigments for nonpaint products (ceramics,
          rubber, mortar, etc.);
     20% color pigments for paint, lacquer, and primers.
                                     47

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8.2  IRON OXIDE PIGMENT SALES
     Table 10 from a recent Bureau of Mines publication [6] shows the
finished iron oxide pigments sold by the processors in the United States
in 1975.  The quantity of natural and synthetic pigments was about the
same 40,815-45,350 t (45,000-50,000 short tons).  However, the value of
the natural pigments was approximately $150 per ton or $0.165 per kg
while that of the synthetic pigments was approximately $750 per ton or
$0.822 per kg.
     These data are in line with the sales price information received by
Crown from various processors as shown below:

          % Iron Oxide Purity           $/Ton               $/kg
                  94                     150               0.165
                  96                     200               0.220
                  98                     250               0.276
                  99                     600               0.660
                  99+                    800               0.882

     Table 11 from the same Bureau of Mines publication [6] gives salient
iron oxide pigment statistics.  The value of all finished pigments sold
was approximately $450 per ton or $0.496 per kg.
     However, for 1975 the first information on iron oxides from steel
plant wastes (dusts and regenerated pickle liquor) is shown in Table 11.
Production by four steel companies was approximately 17.233 million kg
(19,000 tons) with a value of approximately $1 M.  This gives a value of
approximately $0.055 per kg ($50 per ton).   The product was sold princi-
pally for use in ferrite manufacture.
     The value of the product that might be produced by the proposed
process is undetermined.  This uncertainty is probably an order of
magnitude.  Probably, a much larger sample should be produced and submitted
to a number of processors before a more accurate value can be placed on
the product.  An accurate market evaluation may require a pilot plant or
demonstration plant to be built.
                                     48

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                TABLE 10.  FINISHED  IRON OXIDE PIGMENTS SOLD BY PROCESSORS IN THE UNITED STATES, BY KIND

Pigment
Natural:
Brown:
Iron oxide (metallic) 	
Umbers:
Burnt 	
Raw 	
Red: 2
Iron oxide 	
Siennas burnt 	
Yellow:
Ocher 	
Sienna* raw 	

Total Natural 	


Synthetic:
4
Brown: Iron oxide 	
Red: Iron oxide 	
Yellow: Iron oxide 	

Total Synthetic 	
Unspecified, including mixtures of natural and synthetic
Iron oxides 	
GRAND TOTAL 	
1974r
Quanti ty
(short
tons)
13,016
5,754
1,937
34,957
964
7,094
1,055

64,777


9,121
33,653
31,526

74,300
8,467
147.544

Value
(thou-
sands)
2,945
1,933
602
2,829
475
670
379

9,833


6,003
19,888
19,049

44,940
5,839
60.612
1975
Quantity
(short
tons)
10,545
3,964
1,454
28,486
682
4,209
638

49,928


5,730
20,596
19,303

45,629
9,283
104.840

Value
(thou-
sands)
2,087
1,506
542
2,384
338
472
305

7,634


4,494
18,927
18,998

32,419
6,153
46.206
VO
        Revised.
         Includes  black magnetite  and  Vandyke  brown.
        2
         Includes  pyrlte cinder.
         Includes  yellow Iron oxide.
        ^Includes  black magnetite.
Source:  U. S. Bureau of Mines [6],

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                         TABLE 11.  SALIENT IRON OXIDE PIGMENTS STATISTICS  IN THE UNITED STATES
Ol
o

Mine production 	 short tons
Crude pigments sold or used 	 do ...
Value 	 thousands
Iron oxides from steel plant wastes . . short tons
Value 	 thousands
Finished pigments sold 	 short tons
Value 	 thousands
Exports 	 short tons
Value 	 thousands
Imports for consumption 	 short tons
Value 	 thousands

1971
W
W
415
NA
NA
128,300
31,000
r3,984
rl,680
r36,496
T6,496

1972
VI
W
418
NA
NA
152,412
37,673
r4,268
rl,926
r47,271
r8,529

1973
W
W
931
NA
NA
148,802
43,514
r9,888
r3,101
r51,183
r!2,005

1974
W
W
1,429
W
VI
r 147, 544
r60,612
r9,666
r3,466
r54,215
r!6,367

1975
38,073
34,825
1,093
19,252
1,102
104,840
46,206
8,780
2,523
27,979
9,184

           Revised.
         NA~Not available.
         WWithe-M to avoid disclosing indiviudal  company confidential data.
         Source:  U, S. Bureau of Mines [6].

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     Table 12 from the Bureau of Mines document [6] lists the U. S.
producers of iron oxide pigment.  Twenty-one companies reported ship-
ments from 72 plants in 13 States.  Pfizer, Inc., and Reichard Coulston,
Inc., were the largest producers of both synthetic and natural oxides.
Cities Service Company, Columbian Division, was also a leading synthe-
tics producer, while the Prince Manufacturing Company, Delta Color &
Supply Company, and Blue Ridge Talc Company, Inc., were significant
producers of finished natural pigments.  Ten producers accounted for 95
percent of the 1975 sales of all finished pigments.
     In addition to being in touch with some of the above processors,
Crown is working directly with ferrite manufacturers.  These include:
     Crucible Magnetics Division, Colt Industries,
     Arnold Engineering,
     Stackpole Carbon,
     Allen-Bradley,
     3M Company.
8.3  TECHNOLOGY
     Increasing concern about the environment and pollution control
regulations has led to development of techniques for regeneration of
steel plant wastes.  Several processes developed for the recycling of
hydrochloric acid from ferrous chloride leach liquors also recover iron
oxide as a byproduct or coproduct.  A developing market for these oxides
has led to modifications of systems in order to produce oxides specifi-
cally for the pigment and electronics industries.  The Pori, Woodall-
Duckham, and Keramchemie/Lurgi processes, the Falconbridge fluid-bed
hydrolyzer process, and the Steel Company of Canada, Ltd's, spray roasting
procedures were described 1n the January and February 1975 issues of the
Canadian Mining and Metallurgical Bulletin.
                                    51

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                      TABLE 12.  PRODUCERS OF IRON OXIDE PIGMENTS IN THE UNITED STATES IN 1975
                 Producer
                                                Mailing Address
                                     Plant Location
en
ro
         FINISHED PIGMENTS:

          Blue Ridge Talc Co., Inc	

          Chemalloy, Co., Inc	

          Chemetron Pigments    	

          Cities Service Co., Columbian Div.

          Combustion Engineering, CE Minerals
           Div.                 	
Delta Color & Supply Co	

E. I. DuPont de Nemours & Co.

Ferro Corp., Ottawa Chemical  Div.

Foote Mineral Company 	
          Greenback Industries, Inc.
           Greenback Ferric Div.
          Hercules Inc., C&SP Dept.
          Hoover Color Corp.

          Indiana General Corp. .

          Mineral Pigments Corp.

          New Riverside Ochre Co.
P. 0. Box 39
Henry, Va.  24102
County Line Rd. No. 950
Bryn Mawr, Pa.  19101
491 Columbia Ave.
Holland, Mich.  49423
P. 0. Box 5373
Akron, Ohio  44313

901 East 8th Avenue
King of Prussia, Pa.  19406
1050 East Bay St.
Milwaukee, Wise.  53207
Pigments Dept.
Wilmington, Del.  19898
700 North Wheeling St.
Toledo, Ohio  43606
Route 100
Exton, Pa.  19341
Route 2, Box 63
Greenback, Tenn.  37742
720 Commerce St.
Pulaski, Va.  24301
P. 0. Box 218
Hiwassee, Va.  24347
P. 0. Box 218
Valparaiso, Ind.  46383
7011 Mulrkirk Rd.
Beltsvilla, Md.  20705
Box 387
Cartersvllle, Ga.  30120
Henry, Va.

Bryn Mawr, Pa.

Huntington, W. Va.

St. Louis, Mo., Monmouth
 Junction, N.J., Trenton, N.J.

Camden, N. J.

Milwaukee, Wise.

Newark, N. J.

Toledo, Ohio

Exton, Pa.

Greenback, Tenn.

Pulaski, Va.

Hiwassee, Va.

Valparaiso, Ind.

Beltsvllle, Md.

Cartersville, Ga.

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        TABLE 12 (cont'd)
                        Producer
  Mailing Address
        Plant Location
en
CO
         Pfizer, Inc., Mineral  Pigments  Div.

         Prince Manufacturing Co	

         Reichard-Coulston,  Inc	

         George B.  Smith Chemical  Works, Inc.

         Solomon Grinding Service   	
         Sterling Drug Inc.,  Hilton-Davis
          Chemicals Div	
         Sterling Drug Inc.,  Thomassett Color Div.

        CRUDE PIGMENTS:
         The Cleveland-Cliffs Iron Co	
         Hoover Color Corp.
         Bethlehem Steel  Corp.
          Meramec Mining  Co.
         New Riverside Ochre  Co.
235 East 42d St.
New York, N. Y.   10017
700 Lehigh St.
Bowmanstown, Pa.   18030
15 East 26th St.
New York, N. Y.   10010
1 Center St.
Maple Park, 111.   60151
P. 0. Box 1766
Springfield, 111.  62705

2235 Langdon Fram Rd.
Cincinnati, Ohio  45237
120 Lister Ave.
Newark, N. J.  07105

1460 Union Commerce Bldg.
Cleveland, Ohio  44115
P. 0. Box 218
Hiwassee, Va.  24347
Martin Towers
Bethlehem, Pa.   18016
Box 387
Cartersville, Ga.  30120
Emeryville, Calif., East
St. Louis, 111., Easton, Pa.
Quincy, 111., Bowmanstown,  Pa.

Bethlehem, Pa.

Maple Park, 111.

Springfield, 111.


Cincinnati, Ohio

Newark, N. J.


Ishpeming, Mich.

Hiwassee, Va.

Sullivan, Mo.

Cartersville, Ga.

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                                 SECTION 9

                                REFERENCES
1.   Seeler, J. K., W. E. Thornton, and M.  K.  Householder,  "Sulfuric
     Acid and Ferrous Sulfate Recovery from Waste Pickle Liquor,"  EPA
     660-2-73-032, January 1974.

2.   Higgins, I. R., "Steel Pickle Liquor Treatment by Continuous  Ion
     Exchange by Continuous Ion Exchange and Nitrate Decomposition,"
     U. S. Department of Interior, FWPCA, Project No.  WPRD-41-01  (RI)
     68, 1969.

3.   Higgins, I. R., and J. Ferner, "Split Loop Contactor," U.  S.  Patent
     No. 3,468,707, 1972.

4.   Manche, E. B., "Nitric Acid Pickling," U. S. Patent 2,643,204,
     1953.

5.   American Public Health Association; American Water Works Association,
     Water Pollution Control Federation, "Phenanthroline Method,"  p.
     189; "Standard Methods," 1971.

6.   Collins, Cynthia T., "Iron Oxide Pigments," Bureau of  Mines  Yearbook,
     Vol. I, U. S. Department of-the Interior, 1975.
                                    54

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                                TECHNICAL REPORT DATA
                          (Please read Instructions on the reverse before completing)
1. REPORT NO.
 EPA-600/2-77-127
                           2.
                                                       3. RECIPIENT'S ACCESSION-NO.
4. TITLE ANDSUBT.TLE Closed Loop System for the Treatment
of Waste Pickle Liquor
            5. REPORT DATE
             July 1977
            6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)

Joseph C. Peterson
                                                       8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Crown Chemical Company, Inc.
515 Harmon Street
Indianapolis,  Indiana  46225
                                                       10. PROGRAM ELEMENT NO.
             1BV610
            11. CONTRACT/GRANT NO.

            Grant 8803358
 12. SPONSORING AGENCY NAME AND ADDRESS
 EPA, Office of Research and Development
 Industrial Environmental Research Laboratory
 Research Triangle Park, NC 27711
             13. TYPE OF REPORT ANC
             Final; 7/74-6/77
                           NO PERIOD COVERED
            14. SPONSORING AGENCY CODE
              EPA/600/13
15. SUPPLEMENTARY NOTES TRL_RTp prOject officer for this report is Norman Plaks,
Mail Drop 62, 919/541-2733.
16. ABSTRACT
           The report gives results of a demonstration of the feasibility of converting
ferrous sulfate  (FeSO4-7H2O)--obtained by low-temperature crystallization from
H2SO4 waste pickle liquor generated by the acid-cleaning of steel surfacesto mar-
ketable ferric oxide (Fe2O3).  A closed-loop system is proposed, consisting of a
crystallizer, ion exchange unit, oxidizer, and hydrolyzer.  All acids are recycled,
and the net effect is that FeSO4- 7H2O is consumed and Fe2O3 is  produced.  The
FeSO4- 7H2O solution was contacted with hydrogen ion exchange resin in a continuous
ion exchange unit.  Removal of ferrous ion was 90%.  About 11-15% by weight H2SO4
was generated for recycle to pickling.  The resin was regenerated with 4M HNO3, and
a ferrous-ferric nitrate solution was produced.  This product was heated to 180 C and
contacted with air to get complete oxidation to the ferric state and to oxidize any by-
product NO2 to  HNO3.  The nitrate solution was then hydrolyzed  to Fe2O3 and HNO3
in a continuous  coil autoclave at 205 C.  The HNO3 was about 20% by weight and can
be recycled to the ion exchange unit.  After drying,  the Fe2O3 was about 99% pure.
A preliminary market survey indicates the product may have a value of #0.10-0.80
per kilogram.
17.
                             KEY WORDS AND DOCUMENT ANALYSIS
                DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS  C. COS AT I Field/Group
Pollution
Iron and Steel Industry
Chemical Cleaning
Sulfuric Acid
Circulation
Pollution Control
Stationary Sources
Ferrous Sulfate
Ferric Oxide
Pickle Liquor
13B
UF
13H,07A
07B
18. DISTRIBUTION STATEMENT
 Unlimited
                                           19. SECURITY CLASS (ThisReport)
                                           Unclassified
                         21. NO. OF PAGES
                            55
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
                                       55

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