SEPA
              United States
              Environmental Protection
              Agency
              Industrial Environmental Research EPA-600/2-80-079
              Laboratory          May 198O
              Cincinnati OH 45288
              Research and Development
Control  of  Copper
Smelter Fugitive
Emissions

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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 nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was  consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:

      1.  Environmental Health  Effects Research
      2.  Environmental Protection Technology
      3.  Ecological Research
      4.  Environmental Monitoring
      5.  Socioeconomic Environmental Studies
      6.  Scientific and Technical Assessment Reports (STAR)
      7.  Interagency Energy-Environment Research and Development
      8.  "Special" Reports
      9.  Miscellaneous Reports

This report has been assigned  to the  ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research  performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental 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.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia  22161.

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                                           EPA-600/2-80-079
                                           May  1980
         CONTROL OF COPPER SMELTER
             FUGITIVE  EMISSIONS
                     by

              Timothy W.  Devitt
         PEDCo Environmental,  Inc.
             11499 Chester Road
          Cincinnati, Ohio  45246
          Contract No. 68-02-2535
               Project Officer

              A. B. Craig, Jr.
   Metals and  Inorganic Chemicals Branch
Industrial Environmental Research Laboratory
          Cincinnati, Ohio   45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
      OFFICE OF RESEARCH AND DEVELOPMENT
    U.S. ENVIRONMENTAL PROTECTION AGENCY
           CINCINNATI, OHIO 45268

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                          DISCLAMIER

This report has been reviewed by the Industrial Environmental
Research Laboratory-Cincinnati, U.S. Environmental Protection
Agency, and approved for publication.  Approval does not signify
that the contents necessarily reflect the views and policies of
the U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or
recommendation for use.
                               11

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                           FOREWORD

When energy and material resources are extracted, processed,
converted, and used, the related pollutional impacts on our
environment and even on our health often require that new and
increasingly more efficient pollution control methods be used.
The Industrial Environmental Research Laboratory - Cincinnati
(lERL-Ci) assists in developing and demonstrating new and
improved methodologies that will meet these needs both efficiently
and economically.

This report evaluates potential solutions for the collection of
fugitive emissions from copper smelters.  A brief estimate of
emission rates has been provided based on available sampling
reports.  The results of this investigation will enable EPA to
identify potential control technology applications not currently
used by the domestic industry and to conduct engineering testing
and evaluation on these technologies.  Questions or comments
regarding this report should be addressed to the Metals and
Inorganic Chemicals Branch of the Industrial Environmental
Research Laboratory in Cincinnati.
                        David G. Stephan
                            Director
         Industrial Environmental Research Laboratory
                           Cincinnati
                              iii

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                                  ABSTRACT
     This report presents  the results of a study of fugitive emission con-
 trols  for the copper  industry.  The study was conducted by PEDCo Environ-
mental, Cincinnati, Ohio,  under contract to the United States Environmental
Protection Agency.

     During the study period, many of the domestic primary copper smelters
were visited to investigate current controls being used and potential appli-
cations which might be proposed.  The purpose of the study was to document
improved controls as well  as identify avenues for new research where controls
are currently unavailable.

     The report presents existing and proposed emission control devices for
many of the furnaces commonly used in the primary copper industry, as well
as for hot metal transfer devices such as launders and ladles or other
transport devices.   Several of the devices that are reported are currently
under study by the Nonferrous Metals and Minerals Branch to determine their
control effectiveness on both the pilot and full-scale application.
                                    iv

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                            CONTENTS
                                                            Page

Figures                                                       VI
Tables                                                        IX
Acknowledgment                                                 x

1.    Introduction                                              1

2.    Overview of Copper Smelting Processes                     2

3.    Basic Copper Smelting Processes and Related
       Emissions                                               6

          Dryers and Roasters                                  6
          Reyerberatory Furnace                                9
          Peirce-Smith Converter                              12
          Anode Furnace                                       19

4.    Alternative Copper Smelting Processes and
       Related Emissions                                      20

          Noranda Furnace                                     20
          Electric Furnace                                    22
          Flash Smelting Systems                              24
          Hoboken Converter                                   28

5.    Summary of Fugitive Emissions from Copper
       Smelters                                               33

6.    Current Controls and Proposed Modifications              47

          Hooding Systems                                     49
          Roof Monitors                                       63
          Building Enclosure                                  63
          Air Curtains                                        64

7.    Proposed Alternative Controls and Process
       Changes                                                67

          Cascading System, Staggered System, and
            Induction Pumping                                 67
          Oxygen Enrichment                                   69
          Q-BOP Furnace                                       72
          Crane Evacuation of Ladle Emissions                 74
                               v

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                      CONTENTS (continued)
          Floor-Operated Charging                             74
          Top-Covered Bottom-Pour Ladles                      74
          Individual Furnace Enclosures                       77

8.   References                                               80

Appendix A     Cost Analysis                                  81

Appendix B     Trip Report:  Mitsubishi Metal Corp.,
                 Onahama, Japan                               94
                              VI

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                             FIGURES
Number                                                      Page
  1       Locations of Primary Copper Smelters in the
            United States                                      3
  2       General Flowsheet of the Copper Industry in
            the United States                                  5
  3       Countercurrent Direct-Heat Rotary Dryer              7
  4       Multiple-Hearth Roasting Furnace                     8
  5       Fluid-Bed Roaster                                   10
  6       Reverberatory Smelting Furnace                      11
  7       Peirce-Smith Converter                              13
  8       Matte Charging Operation                            15
  9       Position of the Converter During Slagging or
            Blister Copper Pouring                            16
 10       Noranda Continuous Smelter                          21
 11       Electric Smelting Furnace                           23
 12       Outokumpu Flash Smelting Furnace                    26
 13       INCO Flash Smelting Furnace                         27
 14       Hoboken Converter                                   29
 15       Hoboken Converter with Swingaway Hood               32
 16       Material Balance:  Multihearth Roasting Furnace     35
 17       Material Balance:  Reverberatory Furnace After
            Multihearth Roaster                               36
 18       Material Balance:  Peirce-Smith Converter After
            Reverb and Multihearth                            37

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                       FIGURES (continued)
Number
 19       Material Balance:   Fluid-bed Roaster                38
 20       Material Balance:   Reverberatory  Furnace  After
            Fluid-bed Roaster                                 39
 21       Material Balance:   Peirce-Smith Converter After
            Fluid-bed and Reverberatory Furnace                40
 22       Material Balance:   Noranda Continuous  Smelter        41
 23       Material Balance:   Peirce-Smith Converter After
            Noranda Furnace                                    42
 24       Material Balance:   Outokumpu Flash Smelting
            Furnace                                           43
 25       Material Balance:   Peirce-Smith Converter After
            Outokumpu Furnace                                 44
 26   f    Material Balance:   Electric Smelting Furnace         45
 27       Material Balance:   Peirce-Smith Converter After
            Electric Furnace                                   46
 28       Secondary Converter Hood  Configuration              50
 29       Ajo  Smelter,  Secondary Emission Collection
            System (Sheet 1 of 2)                              52
 30       Ajo  Smelter,  Secondary Emission Collection
            System (Sheet 2 of 2)                              53
 31       Side View of Peirce-Smith Converter  with
            Hooding in Position                                54
 32       Front View of Fixed, Movable,  and  Gate Hoods         55
 33       Peirce-Smith Converter with Hooding  Extended         56
 34       Side View of Peirce-Smith Converter  During Collar
            Pulling or Blister Copper Ladle  Removal, with
            Hooding Retracted                                 57
 35        Enclosed Swingaway  Converter Hood  of Nippon
            Mineral  Company                                    58
                             van

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                       FIGURES (continued)
Number                                                      Page
 36       Air curtain Fugitive Control System                 66
 37       Cascading Gravity Flow                              68
 38       Fugitive Emission Collection System for
            Cascading Gravity Flow                            70
 39       Fugitive Emission Collection System for
            Cascading/induction/gravity Flow                  71
 40       Q-BOP Furnace Enclosed in a "Doghouse" to
            Prevent Fugitive Emissions                        73
 41       EOT Crane with Telescopic Stiff Leg                 75
 42       Modified Charging Machine                           76
 43       Hydraulic Cylinder Mounted on Barrel of Ladle
            Rigging Raises and Lowers Stopper Rod to
            Control Flow of Molten Steel from Ladle to
            Ingot Mold                                        78
 44       Individual Furnace Enclosure                        79
 B-l      Schematic of the Onahama Converter Emission
            Control System                                    97
 B-2      Converter Hooding Arrangement                       98
                               IX

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                             TABLES

Number                                                     Page

  1       Estmated Fugitive Emissions from Copper
            Smelting in Various Process Arrangements          34

  2       Summary of Current Fugitive Emission Control
            Systems                                          48

  3       Positions of Movable Hoods                         61

  4       Estimated Retrofitted Hooding
            Efficiencies                                     62

 A-l      Estimated Capital Costs  of Secondary Hooding
            at Multiconverter Plant without Baghouse          85

 A-2      Estimated Capital Costs  of Secondary Hooding
            at Multiconverter Plant with Baghouse            86

 A-3      Estimated Annual  Operating Costs  of  Secondary
            Hooding at a Multiconverter Plant  without
            Baghouse                                         87

 A-4      Estimated Annual  Operating Costs  of  Secondary
            Hooding at a Multiconverter Plant  with
            Baghouse                                         88

 A-5      Estimated Capital Installed Costs of Air Curtain
            Type Hooding with Baghouses at Multiconverter
            Plant                                             90

 A-6      Estimated Annual  Operating Costs of  Air Curtain
            Type Hooding with Baghouses at Multiconverter
            Plant                                             91

 A-7      Relative  Cost  Evaluation  of Alternative and
            Existing Systems                                  92

 A-8       Estimated Energy  Requirements for Control of
            Fugitive (Gaseous  and Particulate)  Emissions
            at  Intakes and  Discharge  Points                   93

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                         ACKNOWLEDGMENT


     This report was prepared under the direction of Mr. Timothy
W.  Devitt.   Mr.  L.  Yerino was  the  Project  Manager.   Project
Officer  for the  U.S.  Environmental  Protection Agency was  Mr.
A.B.  Craig,  Jr.,  of  the  Industrial  Environmental  Research
Laboratory,  Cincinnati.

     The helpful  suggestions  from plant officials of the copper
smelting  facilities and Mr. Henry Dolezal of the U.S. Bureau of
Mines are appreciated.

     The report  was written -by Mr. L.  Yerino,. Mr.  T.K. Corwin,
and Mr.  R.  Price.  The  cost and  energy  calculations were com-
puted by Mr. L. Yerino and Mr. M. Giordano.
                              XI

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                            SECTION 1

                          INTRODUCTION
     This  report  deals  with  fugitive  emissions  from  copper
smelting  and with emission  control  measures.  The PEDCo  study
involved  evaluation  of  the  controls  now  used  in  the  copper
smelting industry and development of suggestions for  alternative
control devices and practices.

     A brief overview  of copper  smelting processes  (Section 2)
is  followed  by  a more  detailed  analysis  of  the  conventional
processes, identifying the portions  of the  operating cycle that
produce  fugitive  emissions  (Section 3).  Emphasis is  placed on
the Peirce-Smith  converter,  which is  one of  the  major emission
sources in copper smelting.

     Section 4 describes some of the alternative process systems
now in limited use  in  the United States and in other countries.
These newer  types of  furnaces  and converters,  although usually
designed  primarily  to  facilitate production,  also  reduce  the
generation of fugitive emissions  and  therefore may  be regarded
as possible means of emission control.   Section 5 summarizes the
fugitive emissions from both conventional and alternative copper
smelting  processes;  the  values are based  the small  amount of
usable published data.

     The  balance  of the  report concerns emission control mea-
sures.  The devices and practices in current use are considered,
along  with  proposed  modifications  that might enhance control
efficiency (Section 6).   Finally,  some alternative control sys-
tems are  presented  (Section  7); these include potential adapta-
tions of equipment now used in other industries and also changes
in the smelting process, ranging from  introduction of relatively
simple  process  devices  to  major  process  changes.   Potential
problems  associated with  operation of  new equipment, especially
in  retrofit  installations,  are considered,  along with the po-
tential  benefits  in  reduction  of fugitive  emissions.   Tables
indicating order-of-magnitude  costs  of  current and  alternative
control measures are given in Appendix A.

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                             SECTION 2

               OVERVIEW OF COPPER SMELTING  PROCESSES


      The copper produced by the  domestic primary copper industry
 is  recovered mainly  from sulfide  ores containing  a variety of
 minerals.   Small amounts of copper  are  also  recovered  from oxide
 ores,  low-grade waste,  and imported ores.  Because most of the
 domestic ore is  mined in  the southwestern  states,  most of the
 plants  are located in that area.   Figure  1 shows the locations
 of  the  16  primary copper smelters in the  United States.   The
 smelting processes recover copper  while  removing most  of the
 impurities  from the copper ore.   Refining removes the remaining
 impurities.

      Copper  is  recovered from  copper  ores primarily  by pyro-
 metallurgical  processing; some hydrometallurgical processing is
 done  also.   Pyrometallurgical processes convert ore concentrate
 into  an impure copper called blister copper.  The process steps
 may  consist of roasting  or  drying, smelting,  converting,  and
 fire  refining.   The  anode copper product, which may contain as
 much  as  99.8 percent  copper,  is  sent to an electrolytic refinery
 for final purification.

      The ore concentrate,  containing about 25 percent copper, is
 generally  conveyed to the  smelter  by rail or truck and stored.
 From  that point, different process  steps in  various combinations
 are  used at  different  smelters.   The  following  brief process
 description deals  with smelting  in  a reverberatory furnace, and
 the Peirce-Smith converter,  the  most common process in domestic
 use today.

     From storage  the ore concentrate is  conveyed to a dryer or
 roaster.  After processing, the dried or partially roasted (cal-
 cined) ore concentrate is usually  transferred in a larry car to
 a reverberatory  furnace,  into which it is charged through pipes
 and/or hoppers  located at the top  or along  the side walls.   The
 concentrate is  melted by reverberatory  heating.   With the addi-
 tion  of  a  silica fluxing agent,  the melt  forms a copper-bearing
matte layer  and a waste slag layer.   The matte  is tapped near
the bottom of  the  furnace, and the  lighter  slag  is  tapped  at a
higher elevation.  The slag is collected in  a slag pot or ladle,
carted to a disposal area, and dumped.

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    ASARCO  (TACOMA)-
 ANACONOA (ANACONDA)-
KENNECOTT (GARFIELD)-

  KENNECOTT (McGILL>
    KENNECOTT (HAYDEN)
   INSPIRATION (MIAMI)
       ASARCO (HAYDEN)
    PHELPS-DODGE (AJO)
    MAGMA (SAN MANUEL)

PHELPS-DODGE (DOUGLAS)
PHELPS-DODGE (HIDALGO)

    KENNECOTT (HURLEY)
      ASARCO (EL PASO)
                                             COPPER RANGE  (WHITE  PINE)
                                   —i-,_ _

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PHFI P5-nnDRF
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                                                                   CITIES SERVICE
                                                                    (COPPERHILL)
                                     (MORENCI)
                 Figure 1.   Locations of primary copper smelters in the United  States.

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     The  matte is  collected in  a ladle and  is transferred by
crane  to  a Peirce-Smith converter, which is a horizontal cylin-
drical  furnace.   This  furnace  converts the matte  into blister
copper and slag by reaction with  air blown in from below the top
of the bath  line.   The reaction  is exothermic.  The slag, which
contains  recoverable copper,  is  poured  from  the mouth  of the
converter  into a  ladle,  then returned to the reverberatory fur-
nace.   After  the  final  blowing,  the  blister  copper contains
about  98  to  99 percent copper.   It is poured into a ladle, then
transferred  to  an anode  furnace, usually gas-fired,  which com-
pletes  the  smelter  refinement  of copper.   The  anode copper,
containing over 99.5 percent copper,  is poured  from the furnace
into molds or a continuous casting wheel.

     The anode copper  molds  range in weight from 209 to 454 kg.
They are  cooled  by  quenching,  then stored or  loaded onto rail
cars for  delivery to  a  refinery.  Figure 2 is  a general flow-
sheet  representing  the  copper  industry  in  the  United States.
The  figure shows the  traditional pyrometallurgical  steps just
described, as well as alternative processes currently in limited
use.

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                                             SLAG TO DUMP
Figure 2.  General  flow sheet of the copper  industry in the United States.

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                             SECTION 3

       BASIC  COPPER  SMELTING  PROCESSES  AND  RELATED  EMISSIONS


 DRYERS AND ROASTERS

      Some smelters use rotary dryers or roasters to precondition
 the concentrate before smelting.   At least seven smelters either
 dry  their concentrates  onsite  or  process feed  that has  been
 dried at a concentrator plant.   The main functions of dryers and
 roasters  are  to  remove  moisture and  some impurities from the
 concentrate and to preheat the  feed to the smelting furnace(s).

      Figure 3 shows a countercurrent,  direct-heat rotary  dryer.1
 "Green" concentrate  is charged  to the  dryer through the  feed
 chute.   By means  of  lifting  flights,  rotation of the dryer, and
 declination of the unit from the  feed end to  the discharge  end,
 the concentrate is  dried  and moved to the point  of discharge.
 The degree of  drying achieved  depends on the residence  time  of
 the concentrate in the dryer and  the temperature throughout the
 dryer.   Fugitive  emissions occur  at the discharge  and charging
 ends  during  upsets or when  concentrate is charged  improperly.

      Roasters used  at domestic smelters  are  of two  varieties:
 multiple-hearth and  fluid-bed.    Among the  domestic  smelters,
 four  plants have multiple-hearth  and  four  have  fluid-bed units.
 In  addition to  removing  moisture from charged  concentrates and
 preheating them for  charging  to  a  smelting furnace, a  roaster
 also  serves  the important function  of partially removing  some
 sulfur  from the concentrate to give  a  working  balance of  copper,
 sulfur,  and iron  in  the  calcine product.  Basically, sulfur  is
 removed by converting it to S02 gas.   This  is done  by maintain-
 ing control of  temperature  and air  in the roaster so that the
 sulfur  will  ignite and burn  (oxidize).   The roasting  process
 also  oxidizes iron in the concentrate  to  ferric  oxide, which can
 react with  silica  and  be   removed  as  slag  in  the smelting
 furnace.   Roasting also helps  to volatilize  impurities  such  as
 arsenic  and antimony,  and thus  facilitates their removal down-
 stream.

      The  conventional  multiple-hearth  roaster,  illustrated  in
 Figure  4,   is  cylindrical  and  vertical and  has  from seven  to
 twelve  hearths.   The  casing  is  steel,  lined  with  refractory
brick.   Concentrate  is  charged onto  the top hearth, on which
rabble  arms,  driven  by a central  shaft,  move  the  feed.  The
 rabble  blades or "plows"  push the concentrate toward the center
                               6

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                    FRICTION SEAL

             FEED CHUTE
      INLET HEAD
(COUNTER FLOW ONLY)

      SPIRAL  FLIGHTS
     NO.  1  RIDING  RING

           TRUNNION AND
            TRUST ROLL
             ASSEMBLY
     GIRT
     GEAR
                                        KNOCKER
                                                                 BREECHING
                                                                   SEAL
        NO. 2
       RIDING
        RING
                          DRIVE
                        ASSEMBLY
LIFTING
FLIGHTS
                                           BREECHING
TRUNNION ROLL
  ASSEMBLY
DISCHARGE
                  Figure 3.  Countercurrent direct-heat rotary dryer
                (combustion chamber not shown).  (Adopted from Ref. 1.)

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 RABBLE
  ARM
RABBLE
BLADE
   CALCINE
                                 HOT AIR
                                TO EXHAUST
                                             AIR
NATURAL
 GAS
                                    COOLING
                                      AIR
  Figure 4.  Multiple-hearth roasting furnace.

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of the hearth,  from  which it cascades through an opening to the
hearth below.   Plows  on  the  next hearth push the concentrate to
the periphery,  from  which it falls to the hearth below,  and so
on.   This  gradual movement  of  concentrate  back and  forth and
down through the hearths exposes the surfaces of the concentrate
and permits the partial roasting of calcine to take  place.

     Off-gases  from  a multiple-hearth roaster are approximately
150° to 200°C.  Particulates  in the gas stream are  usually col-
lected by an electrostatic precipitator; the outlet  gas contain-
ing some  S02  and  volatilized  compounds  is  ducted  to  a stack.

     The fluid-bed  roaster,  illustrated  in  Figure  5,  is cylin-
drical and performs  the same  function  as  the  multiple-hearth
unit,  but works on an entirely different principle.   Rather than
being  roasted on hearths,  the  concentrate  particles  are  sus-
pended by  an  air  stream moving upward.   Each particle  of the
suspended  "bed"  is  in constant  agitated  motion  and is in inti-
mate  contact with the air  stream.   Because  this  fluidization
roasting exposes  much more of  the overall  surface  area of the
concentrate,  the  reactions   are  almost  instantaneous.   Also,
oxygen  in   the  air  within  the  roaster  completely  reacts  with
sulfur and iron;  thus the outlet  gas  contains a higher concen-
tration  of  S02  than  that   generated by   the  multiple-hearth
roaster.   This  concentrated  S02  stream is sent to an acid plant
for SC>2 removal.

     Fugitive  emissions  from  the  roaster  occur  by  leakage
through the  shell  or  open ports and  during the filling of the
transfer car.
REVERBERATORY FURNACE

     The workhorse of the U.S. copper industry is the reverbera-
tory furnace (reverb), which was first introduced in 1879 and is
still used  in  a  modified form at 11 of the 16 domestic smelters
(Figure  6).   The  reverb  is  an  arch-roofed  or suspended-roof
horizontal chamber, approximately 35 m long and 10 m wide.  Heat
is supplied by fossil-fuel-fired burners  located  at one end of
the furnace.  The reverb receives the charge from the roaster or
dryer  and,   with  heat  supplied from  the  burners,  reduces the
charge to matte and slag.  The reverb is extremely flexible with
respect  to  concentrate composition  and  is capable of accepting
as much as 1800 Mg of material per day.

Operation

     Although  methods  vary considerably,  reverbs  are generally
charged either through  the furnace top or along the top portion
of the  side walls.  Belt  slingers  (high speed conveyors), hop-
pers, and Wagstaff guns (inclined chutes) are used to distribute

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TUYERE
HEADS
                                 FUGITIVE
                                 EMISSIONS;
                                 NO VALUES
                                 AVAILABLE
OFF-GAS
   I
               Figure 5.  Fluid-bed roaster.
                             10

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        CALCINE
      FUEL
CONVERTER
 SLAG
AIR AND
OXYGEN
         BURNERS
                                                                      OFF-GAS
MATTE
                                SLAG       CHARGING PIPES
                  Figure 6.  Reverberatory smelting furnace.
                                      11

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 the  charge  over  the  molten bath.  Drag  chains and screw  con-
 veyors have  also  been used  for  charging.   One plant  processes
 "wet, unroasted"  concentrate charged  to the  furnace by means  of
 charge cans.

      In operations  at this  plant,  the concentrate  is  conveyed
 from a filter plant,  and lime  rock is added.   An  electric over-
 head travelling (EOT)  crane  places the charge can  above one  of
 the  slingers  (high-speed belt  conveyors),  which  are adjustable
 in height and angle.   One of the  retractable  charging port doors
 on the side of  the  furnace  is  raised, and feed from the can  is
 discharged onto the furnace  bath  area.  Slag is drained period-
 ically from one end of the  furnace and conveyed by  launders  to
 slag pots.  The slag  can be cooled,  solidified,  granulated,  or
 dumped molten.    Matte  is  withdrawn  periodically  through  tap
 holes in the lower furnace wall.   The matte  flows down launders
 and into  ladles,  which are  conveyed  by  overhead cranes to the
 converter.   Outlet  gases from the  reverb  are generally passed
 through waste  heat boilers to recover  as much of the heat of the
 combustion gas as possible.. Usually, the gases are cleaned  of
 most of the particulates  by means  of electrostatic precipitators
 and vented to  the  atmosphere.

 Emissions

      The  fugitive  emissions  from or in the vicinity of  a reverb-
 eratory furnace   occur  at  openings  in  the  furnace  brickwork
 (caused by inadequate  repair and  maintenance or length of time
 in service);   during  charging of  calcine  or  green  concentrate;
 during  addition of converter slag to  the  furnace; at  the slag
 and matte  launders during tapping operations;  and by leakage  at
 the uptake and the waste  heat boiler.
PEIRCE-SMITH CONVERTER

     The  Peirce-Smith  converter  is  a  horizontal,  refractory-
lined, cylindrical  furnace,  generally about 4 m in diameter and
9 m  long.   An opening in the  horizontal  side  serves  as a mouth
for charging feed materials, discharging  the products of combus-
tion,  and  pouring slag and blister  copper (see Figure 7).  The
converter  can  rotate through  an arc of  about 150 degrees from
the vertical for operational purposes.  First  developed in 1909,
the Peirce-Smith  converter  is  now used at 15  of the 16 domestic
copper smelters, with as many  as 9 units  installed at one plant.
Two  or  three  converters   are generally associated with each
smelting  furnace.   The  Peirce-Smith converter  is  a relatively
efficient  furnace, whose high  rates  of air flow permit both the
charging of bulky materials and large copper  throughputs, typi-
cally about 9 Mg of blister copper per blowing hour.
                               12

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TUYERE
PIPES
                          OFF-GAS
                          «    . •-•*•
                                                         SILICEOUS
                                                          FLUX
                          PNEUMATIC
                          PUNCHERS
                Figure 7.  Peirce-Smith  converter.
                                  13

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 Operation:   General

      In  the  smelting  process,  the  converter  receives molten
 matte consisting of  copper,  iron,  sulfur,  and small amounts of
 other elements.   The  matte contains 40  to 45 percent  copper  from
 the  reverberatory furnace;  flux  is added  from  bins  or hoppers
 located adjacent to the  converter.  Air for combustion is forced
 through the tuyeres,  a  series  of holes in  the side of  the  con-
 verter 6 to 8 inches below the normal bath surface.   Oxygen in
 the  air reacts with  the iron sulfides  to form an iron  silicate
 slag;   this  is  removed,   and  the  remaining  copper  sulfide is
 oxidized to blister  copper.  The  reaction is exothermic.   The
 blowing operations remove iron,  as  a  slag  iron silicate,  and
 sulfur,  as  sulfur  dioxide.   The resultant product  is blister
 copper,  which  is  poured  into ladles and transported to the anode
 furnace.

 Operating Phases  of a Peirce-Smith  Converter

      A Peirce-Smith  converter ready to come on line  is first
 preheated,  usually by gas or oil-fired burners,  until  the  con-
 verter can  accept a hot  charge.  For charging, the converter is
 in  a  "rolled out"  position ready to  accept matte.   A  ladle of
 matte  is  transferred  by  the EOT crane from  a smelting furnace to
 the  converter.   The  hot metal is poured  from a ladle  into the
 converter (Figure 8).  Three to four ladles of matte  are charged
 to the converter in this  manner  and blowing begins.  A  total of
 10 to 12 ladles of copper matte  may be charged during  the  slag
 blows.   A  ladle  of  cold dope (cold  material such  as copper,
 scrap,  or high-copper slag) also may be charged  during  one  more
 of  the slag blows.   A  fluxing agent,  generally  silica, usually
 is  added.  Before the  converter  is tilted back to  its upright
 position, an  air blow is  initiated; as  the converter is tilted,
 this  air  stream prevents  the hot  metal  from clogging  the tuyeres
 (typically  40 to  50).  Blowing rates range  from 42,500 to 68,000
 m3air/h.

     As the operation proceeds, the lower-density slag floats on
 top  of the  molten layer.   As  the slag builds up, the converter
 is rolled out  and slag  is  removed into  a ladle  (Figure  9).  The
 slag,  containing 6 to 8  percent copper,  can be returned  by over-
 head  crane  to  the smelting furnace.    Additional  matte and/or
 cold  dope are  charged to  the  converter  as  required,  and blowing
 begins  again.   Slag  is   again removed, and  the operations are
 repeated  until  enough   copper sulfide  has accumulated in the
 converter.  The  slag  blows are then complete, and the finish or
 copper blow begins.

     During  the  slag and copper  blowing periods, sulfur in the
 copper/sulfur/iron matte reacts  with  oxygen  in the blowing air
 to form sulfur dioxide (S02),  most of which is discharged into a
primary hooding system.   The concentration  of the S02 gas during


                                14

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                   ,
                   •ass.-*
Figure 8. Matte charging operation,
         15

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                                                     SLAG LADLE OR
                                                     BLISTER COPPER
                                                         LADU
Figure 9.
Position of the converter during slagging or
     blister copper pouring.
                            16

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the  slag  and copper blows, even with  the  infiltration of dilu-
tion  air,  is usually great  enough that the  gas  is sent  to an
acid  plant  for production of sulfuric  acid.   With the elimina-
tion  of impurities, mainly  the sulfur as  S02 and iron  in the
slag, the matte  is  converted to the blister copper product that
consists of about 98 to 99 percent copper.

     Pouring  of the  blister  copper,   like  the  slag,  is  done
through  the mouth  of  the converter   (Figure  9).   The  filled
ladles  of  blister  copper are transferred  by  the  overhead crane
and dumped  into  the anode furnaces or refining furnaces.   Occa-
sionally some  slag  may  be formed in an anode furnace;  this slag
is poured off into a ladle, and then recharged into a converter.

Emissions

     All of the Peirce-Smith converters at primary copper smelt-
ers  in  this country are  equipped  with primary hoods  to  direct
the gas flow from the converter when it is in the upright, i.e.,
blowing  or  "in-stack"  position.   This gas  stream,  containing
particulates  and  S02,  is  passed  through particulate  control
equipment and  at most  smelters  is routed to  an  acid  plant for
S02 removal.

     Fugitive emissions from a Peirce-Smith converter consist of
those that  escape the primary hooding system and those that are
emitted directly from  the  mouth  of  the  converter when  it is
positioned  in  the  "out-of-stack" mode,  i.e.,  when it is receiv-
ing  a cold  or hot  charge,  or when  slag  or  blister  copper is
poured from the mouth of the converter.

     The  primary hooding  system  (Figure  9)  at  most smelters
consists of a  fixed hood with a sliding gate located  above and
slightly away from the converter.  The primary hooding system is
connected by ducting usually to  an  ESP.   The sliding gate is
lowered close to the converter mouth to help guide the emissions
into the fixed hood and reduce the intake of dilution air during
the  blowing  period.    Minimizing   the  dilution  air  serves  to
maximize  the S02 concentration in the gas  stream to an acid
plant.

     Regardless  of  the merits  of  any primary hooding  system,
some  of  which have been  modified  to  increase collection effi-
ciency,  none are 100 percent efficient.  The hooding system with
the sliding gate does  not form a  perfectly  tight seal with the
converter body  (even with the closest  fits, since there must be
some  clearance  between  the  two   to  allow   the  converter  to
rotate).  At some  plants,  because the gates  were retrofitted
rather  than designed  and  installed   as  part  of  the original
smelter, the gates  may  not completely cover the  converter mouth
nor  seal   tightly   to   the primary hood.   Emissions  therefore
                               17

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 escape  through the  open  areas  between the  gate,  the  primary
 hood, and  the converter mouth.  The emission  rate  is  dependent
 on  the  size  of  the openings  and the  discharge gas  flow  rate
 through the mouth of the converter to the hooding system.   Leaks
 can  also occur between the edges of the gate  and the  converter
 primary hood.  Additionally,  emissions  from even a well designed
 and  installed hood  system will  increase in  time  unless  pre-
 ventive maintenance  is practiced  to forestall  the effects  of
 normal wear and tear.

      During  the  frequent  transport  and charging of materials,
 bumping of a  gate  and  guide  may cause  them to  become misaligned
 or damaged, thus allowing  additional fugitive  emissions.   Emis-
 sions vary  among smelters because  of  restrictions  on  overhead
 space for  installation of the primary  hood.   At smelters  that
 were originally designed with low crane  rail  runways, the  clear-
 ance is  limited.   In  these  plants the  optimal slope  and  con-
 figuration  of the primary hoods have  been compromised by  lack of
 space,  and flow of the gases  from the mouth  of the  converter is
 impeded.   Although  the installed  system may  be the best  pos-
 sible,  it does permit fugitive  emissions.

      The  second  category of fugitive emissions from a Peirce-
 Smith converter  consists  of  those  emitted directly  from  the
 mouth of  the  converter in  the  rolled-out  position.    As  the
 converter  is  rolled-out, the gate is usually moved up and  away
 from the converter mouth  for clearance.   The blast air is  left
 on until  the bath is below the tuyere level.   Even  if  the blast
 air flow is  reduced to  some minimum rate,  fugitive emissions are
 still rather  heavy.   Also,  fugitive  emissions  are heavy  when
 matte is  charged  to  the converter.    Unless a converter  is
 equipped  with  a  secondary  hooding system,  emissions that occur
 during  charging,  pouring of  slag,  or pouring  of blister  copper
 are uncontrolled.  When the blast  air is turned off,  the  hot
 bath still  generates some  fugitive emissions,  which continue to
 leave the converter at  a lower  rate.  Fugitive  emissions usually
 become  heavy  also  when  cold  material  such  as copper  scrap  is
 charged  to   the converter.   Before a Peirce-Smith converter  is
 rolled  back,  the blast air is  turned on again.  Emissions  from
 within  the   converter  are  blown  out of  the mouth  and are  not
 reasonably  controlled until the  gate is down  and the converter
 is  in the in-stack position.

 Characterization of Emissions

      To date,  the  fugitive emissions  from Peirce-Smith conver-
 ters  have not  been collected for the purpose of chemical charac-
 terization.   Since  data are  lacking, the following  is  an esti-
mate  of  the composition by weight of the  constituents:  S02 -
 90%,  Cu - 4%,  Fe - 4%,  and S - 2%.  The  fugitive emissions  also
 contain some trace metals such  as arsenic and lead.
                               18

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ANODE FURNACE

     The  final  process at  a  copper smelter is  purification of
the blister  copper in  an  anode furnace.  The  anode furnace is
usually  cylindrical,  very  similar  in  shape   and size  to  a
Peirce-Smith  converter,  and  generally  lined  with  magnesite
refractory.  Like  the  Peirce-Smith converter,  the anode furnace
is tilted or rolled out to receive its  charge,  which  is poured
from a blister ladle carried from the converter by an EOT crane.
In the upright position, the furnace is blown with a gas high in
hydrogen  content.   The  reaction that  takes place removes oxygen
from  the  bath.   This  deoxidation  of  the cuprous  oxide (Cu20)
reduces it to  nearly  pure copper.  Most, but  not  all,  of the
oxygen is  removed  from the molten bath.  A small oxygen residue
in the  bath is  necessary  to  cast  a  shape free  of blisters or
shrinkage holes.

     The  anode  furnace also serves  as a  holding furnace,  from
which the  anode  copper product is poured, usually into molds on
a continuous casting wheel.  The formed anodes are shipped to an
electrolytic refinery.

     Any  fugitive  emissions from an anode furnace come directly
from  its  mouth when not  hooded.  These  emissions  are minimal.
Most or all  of the sulfur, iron, and other impurities have been
removed in preceding operations.   The  characteristic  "greenish
flame" shooting  a  few feet from the anode mouth during deoxida-
tion  probably  indicates  the  presence  of some  copper  in  the
off-gas stream.
                               19

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                             SECTION 4

               ALTERNATIVE COPPER SMELTING PROCESSES
                       AND RELATED EMISSIONS


      Several alternatives to  the reverberatory furnace and  the
 Peirce-Smith converter are  in use  in  this  country and abroad.
 Some  of these furnaces combine several  of the  conventional proc-
 ess   steps.   In  addition,  these  alternative  processes usually
 generate lesser quantities  of fugitive emissions, and for this
 reason each may be considered  also  as  a  means of  additional  air
 pollution control.

      The alternative  processes, however,  do not eliminate fugi-
 tive  emissions.  As in the  foregoing description of conventional
 smelting processes, this  section briefly  describes the  operation
 of these units  and the points  at which  fugitive emissions occur.
 The  discussion includes  the  Noranda furnace,   the electric fur-
 nace,  flash smelters   (Outokumpu and  Inco),  and the Hoboken con-
 verter .
NORANDA FURNACE

      In  the Noranda continuous  furnace (Figure 10), the roast-
ing,  smelting,  and partial converting  reactions are combined in
a  vessel similar  to a  lengthened  Peirce-Smith converter.   One
U.S. plant  started operating Norandas within the past year.  The
reactor  is  a horizontal,  cylindrical   furnace  about  21 m long.
It  is fired  from both  end walls,  and oxygen-enriched  air is
blown  into  the  matte  layer through  side-mounted  tuyeres.   The
furnace  can  be  rotated on  its horizontal  axis  to  bring the
tuyeres  out of  the  bath  and stop  the smelting  process.   The
compact  design  facilitates process  control,   and  the domestic
Noranda  smelter  is highly  instrumented.   The  Noranda was orig-
inally developed as  a  one-step process that would eliminate the
converter,  thus  significantly reducing capital costs and elim-
inating  the  need  for  a converter  aisle.   In U.S.  commercial
applications  to  date,  however,  the Noranda is  used with a con-
verter  to  allow greater  production,   better   control  of trace
elements, and longer life of the reactor lining.
                                20

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FEEDER
                                      SO?
                                    OFF-GAS
              CONCENTRATE
          PELLETS AND FLUX
HOOD
                                              iiimiiiiiiiiiiiiiiiiiuiiiiniiiiiii^  BURNER
                                   5SLAGE22SSE5
                                               SLAG SETTLING
                                                •*' "• * -"~   '
                    3
SLAG
             AIR TUYERE                  ,      REDUCING GAS

                                   HIGH-GRADE MATTE


               Figure 10.   Noranda continuous smelter.
                                   21

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 Operation

      Concentrate and fluxes are fed  to  the  Noranda  by  a  slinger
 at one  end wall  that  spreads pelletized feed over the molten
 bath.    High-grade  matte,  which  typically  contains  about  70
 percent  copper,  is  periodically  tapped  from  the  side  of  the
 furnace  and  transported  by  ladles  to  standard  Peirce-Smith
 converters,   where  it  is  batch-treated  to remove additional
 sulfur and iron prior to  fire  refining.   Slag  containing 6  to 8
 percent copper is  periodically  tapped from the  end of the vessel
 opposite the  slinger.  The  slag  is  upgraded by milling  to  pro-
 duce  a  concentrate,  which  is  returned  to  the reactor,  and. a
 tailing,  which  is discarded.   The  off-gases  leave  the  Noranda
 furnace through its mouth, where  they  are captured by water-
 cooled hoods and ducted to  a  waste  heat boiler.  The gases  are
 passed  through cyclones   and  electrostatic   precipitators  to
 remove particulate matter, and then  used as feed to a sulfuric
 acid plant.   With  30 percent oxygen  enrichment,  the  off-gases  to
 the  acid plant contain 5  to 6  percent S02.   The  S02 concentra-
 tion is approximately 4 percent without  oxygen  enrichment.

 Emissions

     If uncontrolled, fugitive  emissions  evolve from the  follow-
 ing  areas  around  a Noranda smelting furnace:   between  primary
 uptake  hood and furnace mouth;  from  the mouth when in the rolled
 out position;  around matte  and  slag holes  during tapping; and  at
 the port for  feeding concentrate and  fluxes.


 ELECTRIC  FURNACE

     The  electric  copper smelting  furnace (Figure 11)  has  been
 used  traditionally  in  Scandinavian  areas  where  hydroelectric
 power  is cheap and  fossil  fuels  are expensive.  The first  such
 furnace  in  the  United States started  operation  in  1972; two  more
 smelters have  since  adopted this technology.

     The electric  furnace is rectangular  in  cross-section with a
 firebrick sprung-arch roof.  The largest  furnaces  are about  35 m
 long and 10 m wide.  Carbon electrodes  are  placed in the molten
 slag,  and the heat  required for  smelting is generated by elec-
 trical resistance  of  the slag to the  submerged  arc between elec-
 trode  pairs.   Electrical ratings range  as  high as  51,000  kVA.
 The chemical  and physical  changes that occur in the  molten  bath
 are  somewhat  similar to  those that occur  in a  reverberatory
 furnace.  The  reverberatory furnace  with a  waste  heat boiler  is
more efficient  than the electric smelting  furnace.1
                               22

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                                                OFF-GAS
                      ELECTRIC
      FETTLING  PIPES    P°WER
ELECTRODES
CONVERTER
  SLAG
 LAUNDER
       MATTE
                                       CALCINE
                                                           SLAG
                Figure 11.  Electric smelting furnace.
                                 23

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 Operation

      The charge  of  concentrate and  fluxes  is  delivered to  the
 roof of the furnace  by drag conveyors and then  fed to  the molten
 bath  through  multiple-feed  spouts   near  the  electrodes   and
 between  the   sidewalls.   As  the  charge materials  melt,   they
 settle  into   the bath  and  form  additional  matte  and  slag.
 Separate launders or chutes on  the furnace  end wall are used to
 charge converter slag and reverts.   Matte is tapped into ladles
 from tap  holes placed  in the  hearth area near one end wall.
 Slag is  skimmed from  tap holes  in  the  opposite end wall  and
 delivered by  launders  into  slag pots, which are  usually hauled
 to a dump by  trucks.

      Although originally  designed  as an  alternative to the  use
 of  expensive  fuels  in  Scandinavian  countries,  the  electric
 furnace also  facilitates air pollution control.   Because it  does
 not require  large  amounts  of  combustion  air,   the  volume  of
 outlet gases  is about  an order of magnitude  less  than  those  from
 a  reverberatory furnace.  Sulfur dioxide  concentrations of  2  to
 4  percent can  be expected,  and particulate  emissions should  be
 lower  than from a reverberatory because  of  the lower  gas volume
 and more uniform gas flow.  The electric furnace off-gas at  all
 three  domestic  smelters  is  combined  with  other high-S02   gas
 streams  and fed to contact sulfuric acid  plants.

 Emissions

     Fugitive emissions around  electric  arc furnaces are lower
 than those from  most  reverberatory furnaces.   For example,  the
 electric  arc  furnace   at  the Anaconda  smelter  in  Montana  has
 tight  brickwork, which  prevents the  leakage of  fugitive emis-
 sions  from  the  sides  of the  smelter;  with poor maintenance,
 however,  the  brickwork could be a  source of emissions.  Where a
 hooding  system  is  used     ineffectively over the  slag  ladle
 during  slagging,  emissions will occur.•  Other  sources of fugi-
 tive emissions  are  matte  tapping,  the   converter  slag return
 launder, around the electrodes,  and the calcine handling system.
FLASH SMELTING SYSTEMS

     A recent development in copper metallurgy is the continuous
flash furnace,  which is more  efficient  in terms of energy con-
sumption  and also produces  a  more easily  controlled  stream of
flue  gas  than  the reverberatory  or electric  furnaces.   Flash
furnaces  are of  two  types,  the Outokumpu Oy and the Inco, which
differ primarily in their use  of either preheated air or commer-
cial-grade  oxygen  to sustain  the  smelting reaction.   The flash
furnace is in widespread use throughout the world, although only
one is operating  in  this country,  under license from Outokumpu.
                               24

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The Outokumpu Furnace

     The Outokumpu furnace (Figure 12) combines the functions of
roasting, smelting,  and partial converting in a  single furnace
with three sections—reaction  shaft,  settler,  and uptake shaft.
Dried ore concentrates are injected continuously along with flux
and preheated  air into  the  reaction shaft through concentrate
burners.  Oil  may also be injected into the  shaft.   The finely
divided  concentrate  burns in  a  "flash"  combustion as  the par-
ticles  fall  down through the  shaft,  and the  heat released from
the combustion of the oil and sulfur sustains the smelting reac-
tion.    The process is  similar to  the combustion  of  pulverized
coal.    The molten particles fall  into  the settler part of the
furnace  and  separate  into  matte  and slag layers.   The matte,
which contains 45  to 75 percent copper,  is tapped from the set-
tler and transferred to converters for further processing.  The
slag,  which  contains too much copper to discard,  is  also proc-
essed further in an electric furnace.   From the electric furnace
the copper   containing-material  from the  slag is  sent  to the
Peirce-Smith converter.   The slag  from the electric  furnace is
then dumped.   Outlet gases  from the  Outokumpu furnace are con-
veyed from the uptake  shaft.  They contain 10 to 20 percent S02
and considerable  quantities of  entrained particulate  matter.
The gases are cooled in a waste heat boiler,  cleaned of particu-
lates  in an  electrostatic precipitator, and  then sent for sul-
furic acid production.

     Fugitive emissions  from operation  of  the Outokumpu furnace
can occur  at the  launders  and ladles and from leakage through
the furnace walls and roof.

The Inco Smelter

     The Inco  smelter  (Figure  13)  is similar to a reverberatory
furnace  except  that the  off-gases  are  discharged at  the center
of the  furnace.   The dry ore concentrate  and  fluxing agents are
injected into  the  furnace through both end walls, and oxygen is
also injected  through both  end walls.  Fine  particles are dis-
persed  into  the  furnace,  and  flash combustion of  the sulfides
creates  the  heat required for the smelting.   The molten matter
falls   on the  molten  bath,  again  forming a  matte and  a slag
layer.    Charging is continuous.   The slag, of high copper con-
tent,  is treated for copper  recovery.  The matte grade is higher
than that  of matte  from  the reverberatory furnace.  The volume
of off-gases decreases  as oxygen enrichment is utilized.   Fugi-
tive emissions  from the  Inco  smelter can  occur at the launders
and ladles,  and  by  leakage  from the furnace  sides,  roofs, and
off-take.
                               25

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  PREHEATED
    AIR
                                          OFF-GAS
                                                  SLAG
MATTE
SLAG
                              SETTLER
         Figure 12.   Outotun^i fUsh smelting furnace.
                               26

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           CHALCOPYRITE
     SAND  CONCENTRATE
                    OFF-GAS
  CONSTANT
WEIGHT FEEDERS
      OXYGEN
           OXYGEN
PYRRHOTITE, CHALCOPYRITE
 CONCENTRATES, AND SAND
                                                             OXYGEN
                        SLAG  MATTE
                Figure 13.   INCO flash  smelting  furnace.
                                  27

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 HOBOKEN CONVERTER

      The Hoboken  converter,  shown in Figure 14,  is  an alterna-
 tive to the Peirce-Smith converter.  The Hoboken was  designed to
 largely eliminate the problem  of excess air  infiltration  into
 the  flue  gas  off-take  system.   First  developed  in  the  early
 1930's  in  Belgium,  a  Hoboken  has  been operated  at a  single
 domestic primary  smelter for about  4  years;  Hobokens are  also
 installed at a number of copper plants  in six foreign countries.

      The Hoboken  converter  is similar to the  Peirce-Smith,  but
 is equipped with an integral side flue  at one end of  the  furnace
 for withdrawal  of the  off-gas.    Shaped like  an inverted  f'U",
 this flue,  or  siphon,  rotates with  the converter,   as does  the
 cylindrical  duct  to  which  it  is  connected.   A counterweight
 balances the siphon.   The cylindrical duct  is connected by  an
 airtight rotating joint  to  a fixed vertical duct that leads  to
 the gas  cleaning  system.   The  Hoboken  thus  provides a  direct
 link at all  times between  the  converter and  the gas  off-take,
 regardless  of its  operating position.

      The Hoboken converters at the U.S.  smelter in Inspiration,
 Arizona,  are 4.3  m in  diameter  by 11.6 m long.   Each  converter
 has fifty-two  3.8 cm  diameter  tuyeres;  air  blast  is approxi-
 mately  31,500 Nm3/h.

 Operation

     Matte  from the electric furnace  at  the  Inspiration plant  is
 charged into  one  of the  refractory-lined  Hoboken  converters.
 When the converter is  in the blowing position, the  tuyere line
 is  20  to 25 cm below the bath level, as with  the Peirce-Smith.
 To  operate  as designed,  the  draft at the mouth should be main-
 tained  at zero  or  a  slightly  negative draft; the  design concept
 is  that emissions  will not  escape  the mouth of the converter  in
 this operating  mode  but will be  ducted  to the  end-mounted flue.

     At Inspiration,  temperature  of the gas stream in the siphon
 area of the Hoboken converter is  950° to 1100°.   Gases contain-
 ing S02  from  the converter are combined with the gas  stream from
 the  electric  furnace  and are sent  to the acid  plant  after cool-
 ing  and particulate removal.   So  that flow of S02-containing gas
 to  the  acid plant  can be  maintained,  at least one  converter must
 always  be in  the blowing phase.  A continuous  stream of hot gas
 through the duct system also minimizes condensation.

     Charging,  blowing,  slagging  or skimming, and  pouring  of
blister  copper  pouring are  very  similar to  operations with the
Peirce-Smith  converter.   A  Hoboken  converter  ready to  come
on-line  is  heated  and then  charged  with matte.  The  matte  is
poured  from a ladle,  which is held and  tilted  by the EOT crane
                               28

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                     SIPHON
MOUTH
COUNTER-
 WEIGHT
DROP OUT
CHAMBERS
 Figure 14.  Hoboken converter.
               29

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 hooks,  into the  rolled-out converter.   The initial charge con-
 sists  of several  ladles  of matte.  After  flux is charged, the
 air blast  is  turned  on  to begin the  slag blow.   The bath is
 blown  for  45  minutes  to  1 hour,  then the blow  air  is turned
 down,  the  converter  is tilted,  and  slag is poured off into a
 ladle positioned  on the floor  of  the converter  aisle.  After one
 or  two  ladles of slag  are  poured,  a  similar amount of matte is
 charged  to  the  converter.   When in the  upright position, the
 converter  is blown again to further burn off the sulfur  combined
 with the iron,  and allow the  iron oxide that is formed  to  react
 with the flux to produce  slag.   The off-gas  stream containing
 the sulfur oxidized  during blowing is pulled through the siphon
 to  the uptake duct, then sent  to  an acid plant.  At the  Inspira-
 tion plant,  slag  is poured  off and transferred  in  ladles via the
 EOT crane  and  charged into  the  electric  smelting furnace for
 recovery of the copper.

     As  with the Peirce-Smith converter,  the  slag blow is fol-
 lowed by the blister  copper blow.  The  copper sulfide bath is
 blown  until  all  or  nearly all  of the  sulfur is  burned off,
 mainly oxidized as S02.  Upon  completion of the copper blow, the
 product  is blister copper.   It is poured  into ladles that are
 carried  by  the EOT crane to the anode furnace.

 Emissions

     One major  difference between the  Hoboken and Peirce-Smith
 converters  is  that the Hoboken is not  equipped  with a primary
 uptake  hood  over the  mouth,   but rather  with the  siphon and
 side-mounted flue.   Any  emissions  that  escape   the  mouth are
 fugitive emissions.

     A properly designed,  operated,  and maintained Hoboken con-
verter (such as the one operated by Hoboken Overpelt in Belgium)
generates only minimal  fugitive emissions, even though the mouth
is  not  hooded,  because the converter is  operated under zero or
slightly negative draft.   At  slight negative  draft,   air from
outside  of  the converter   is  sucked into  the  mouth  and exits
through  the converter siphon with the gas stream  containing the
S02 generated during blowing.  Air brought into the converter in
this manner cools the discharge  gas stream  and dilutes the S02
in  the   off-gas   stream, but  this dilution  can  be  minimized.
Slight negative  or zero draft prevents  fugitive emissions from
the mouth of the  converter.

     The  small  amounts of  fugitive emissions  from  a Hoboken
converter  usually occur during charging of  matte  or cold mate-
rial or  during slagging or blister copper pouring.  During these
operations,  the converter  is  rolled out and the  blowing air is
turned down,  but  the  zero  or  slightly negative  draft is main-
tained.   During matte charging, some emissions are released from
                               30

-------
the hot  metal  stream as it flows  from  ladle  to furnace.  Emis-
sions  during  slagging  and blister  copper pouring occur  in  a
similar manner.

     In  summary,  a  Hoboken  converter  that  is  well  designed,
installed, operated,  and maintained generates  small quantities
of  fugitive  emissions.   The  addition  of   a  swing-away  hood
(Figure 15) would minimize emissions during slagging or pouring.
During the blowing periods, fugitive emissions are controlled to
a  much  greater  degree  than  with the Peirce-Smith converter.

     No  characteristics or analyses  of  fugitive  emissions are
available.
                               31

-------
to
       CAPSTAN
        LIFT
       DEVICE
                              TO FUGITIVE
                               EMISSION
                              COLLECTOR
                                                                                                ttt
                                                                                                 • 1 '
                                                    ll
                                                                                                    I
SWIVEL
JOINT
                              Figure 15.   Hoboken  converter with swingaway hood.

-------
                            SECTION 5

       SUMMARY OF FUGITIVE EMISSIONS FROM COPPER SMELTERS


     In  efforts  to determine  typical  quantities  of  fugitive
emissions from  copper  smelters,  the authors consulted the tech-
nical  literature and  undertook  an inquiry  by  telephone  with
knowledgeable persons  in  the  copper industry and in government.
The  literature  search  indicated a minimal  amount of  valid pub-
lished  data  on  process  rates,  emission  rates,  and  emission
characteristics.  In the  course  of the inquiry we learned of no
actual published  measurements of fugitive emissions from rever-
beratory  furnaces,  converters,  or  other process equipment  at
copper smelters.

     We  have therefore  prepared  a set  of  emission estimates
corresponding  to  several  arrangements   of  process  equipment,
summarized  in  Table 1.  For each  combination of process equip-
ment the  emission estimates are  based on maintaining  the  same
production  rate,  303 tons  of  blister copper per day.   The emis-
sion values are based on  data  from several  sources,  primarily
reports  (References  2  and  3)  and  conference  presentations
(References  4  and 5).   Reference 2  was  the  principal source of
the emission estimates.   Data  from all of the sources have been
modified  to accommodate the  selected  production rate  and thus
allow comparison among the several process arrangements.

     Figures 16 through 27  depict material balances for each of
the equipment items listed  in Table 1.  Each figure is intended
to approximate  the  material balance that would  occur  when the
equipment is operated  in  the  specific  combination designated in
Table 1.   Thus, although the Peirce-Smith converter is  a com-
ponent of each  of the  five equipment combinations in the table,
the materials  entering the converter  depend upon the equipment
that precedes  it in the smelting  process;  e.g., matte entering
the converter from  a reverberatery furnace (Figure 18) contains
greater  quantities  of sulfur,  iron,  and other  materials  than
matte  from  the Outokumpu  furnace  (Figure  24).  The  emission
estimates of Table  1 reflect  these differences  and thus provide
an  indication  of  the relative  magnitude  of  emissions  under
various process arrangements.
                               33

-------
         TABLE  1.   ESTIMATED  FUGITIVE  EMISSIONS  FROM COPPER SMELTING
                       IN  VARIOUS  PROCESS ARRANGEMENTS

1.


2.


3.

4.


5.


Multi hearth roaster (Fig. 16)
Reverberatory furnace (Fig. 17)
Peirce-Smith converter (Fig. 18)
Fluid-bed roaster (Fig. 19)
Reverberatory furnace (Fig. 20)
Peirce-Smith converter (Fig. 21)
Noranda furnace (Fig. 22)
Peirce-Smith converter (Fig. 23)
Dryer
Outokumpu furnace (Fig. 24)
Peirce-Smith converter (Fig. 25)
Dryer
Electric furnace (Fig. 26)
Peirce-Smith converter (Fig. 27)
Estimated Fugitive Emissions
S02a
c
4.2
6.5
c
4.2
6.5
2.9
1.5
c
2.9
2.1
c
3.0
6.5
Cub
c
0.16
0.16
c
0.16
0.16
0.11
0.03
c
0.15
0.03
c
0.15
0.19
Feb
c
0.10
0.21
c
0.09
0.21
0.07
0.33
c
0.15
0.38
c
0.07
0.21
Others5
c
0.10
0.11
c
0.12
0.13
0.04
0.12
c
0.07
0.08
c
0.04
0.06
Percentage of sulfur charged to the process equipment, expressed as S02.
Percentage of the total copper, iron, or other materials charged to the
process equipment.
No values available.
                                 34

-------
                                            FEED
Cu
Fe
s
SO
CO
2
2
383.
53.
0
5
(54
(7.
.8)
6)
7.0% VOL. SiO?
CaO^
nthpr
308
308
382
102
5.
34
7
•
6
6
9
9
2
(44
(44
(54
(14
(0.
(4.
.1)
.1)
.7)
.7)
8)
9)
                                                                     FLUX
CaO
SiO?
C02
Other
49.0
97.1
37.3
12.2
(7.0)
(13.9)
(5.3)
(1.7)
                                               HOT AIR
                                              TO EXHAUST
                  RABBLE
                   ARM
                 RABBLE
                 BLADE
                                                        A FUGITIVE
                                                        \ EMISSIONS:
                                                         )MO VALUES
                                                        /AVAILABLE
                                                          AIR:
02
C02
191.5
16.2
(27.4)
(2.3)
NATURAL
 GAS
                   CALCINE
                                                  COOLING
                                                    AIR
                          MATERIAL BALANCE IN  TONS/DAY.
                         NUMBERS IN PARENTHESES  INDICATE
                          CAPACITY OF EACH UNIT.
                         OTHER VALUES ARE BASED  ON 303
                           TONS/DAY OF BLISTER COPPER.
Cu
Fe
S
SiO?
CaO
Other
308.6
308.6
191.4
200.0
54.7
46.4
(44.1)
(44.1)
(27.3)
(28.6)
(7.8)
(6.6)
Figure  16.  Material  balance:   multibearth  roasting furnace.

                                       35

-------
U)
S
Cu
Fe
SiO?
CaO
02
Other
3.7
12.0
239.1
115.2
5.0
69.2
6.9
                00 1103.8
Cu
Fe
S
SiO~
CaO
Other
308.6
308.6
141.4
200.0
54.7
46.4
                                   CALCINE
                                 FUEL
                            INVERTER
                             SLAG
                            AIR AND -SZ
                            OXYGEN
                                    BURNERS
FUG]
SO?
Cu
Fe
S
TJVES
B.T
0.5
0.5
0.2
                                                                                          OFF-GAS
so2
1
14
.7
1
VOL. %-
MATTE
                                                         SLAG
                   CHARGING PIPES
                                              MATERIAL BALANCE IN TONS/DAY
                                              ALL VALUES ARE ON BASIS OF 303 TONS/DAY
                                                OF BLISTER COPPER (SLIGHTLY BELOW
                                                CAPACITY OF UNIT).
                                        MATTE
Cu
Fe
S
CaO
00
2
315.5
238.5
126.6
3.7
47.7

Cu
Fe
S
Si09
CaO
02
Other
4.6
308.7
6.8
315.2
56.0
63.7
53.1
                     Figure 17.   Material balance:   reverberatory furnace  after multihearth  roaster.

-------
 MATTE
Cu
Fe
S
CaO
°2
315.5
238.5
126.6
3.7
47.7
(129.3)
(97.7)
(51.9)
(1.5)
(19.5)
SLAG
so2|
237.0
(97.2)
4% VOL.
                                     OFF-GAS
              TUYERE
              PIPES

SO-
Cu^
Fe
S
FUGITIV
8.2
0.5
0.5
0.2
ES
(3.4)
(0.2)
(0.2)
(0.1)
Fe
Si Op
CaO
02
Other
2.6
115.2
1.3
0.7
8.2
(1.1)
(47.2)
(0.5)
(0.3)
(3.4)
Cu
Fe
S
Si09
CaO
02
Other
12.0
239.1
3.7
115.2
5.0
69.2
6.9
(4.9)
(98.0)
(1.5)
(47.2)
(2.0)
(28.4)
(2.8)

TnU
PNEUMATIC /-»
PUNCHERS *^
BLISTER COPPER
Cu
Fe
Other
303.0
1.5
1.5
(124.2)
(0.6)
L (0.6)
                                                                AIR
°2
[143.3
(58.9)
                                                MATERIAL BALANCE IN TONS/DAY.
                                                VALUES IN PARENTHESES INDICATE CAPACITY
                                                  OF UNIT; OTHER VALUES ARE ON BASIS OF
                                                  303 TONS/DAY BLISTER COPPER.
   Figure 18.   Material  balance:  Peirce-Smith converter  after  reverb  and multihearth.

-------

FEED
Cu
Fe
S
Si09
CaO
Other
308.6
308.6
382.9
102.9
5.7
34.2
oo
CO

FLUX
CaO
Si09
C02
Other
49.0
97.1
37.3
12.2
                                                                 FUGITIVE
                                                                 EMISSIONS;
                                                                 NO VALUES
                                                                 AVAILABLE
OFF-GAS
                                    TUYERE
                                    HEADS
&
v/Uo
127.9
1.7
SOo
CO^
255.8
39.0
13% VOL.
                                                  MATERIAL BALANCE  IN TONS/DAY.
                                                  TONNAGES ARE FOR  CAPACITY  OF UNIT
Cu
Fe
S
Si 0/>
CaO
Other
308.6
308.6
255.0
200.0
54.7
46.4
                                        Figure  19.   Material  balance:   fluid-bed  roaster.

-------
U>
CONVERTER
SLAG
Cu
Fe
S
Si09
CaO^
02
Other
12.0
240.0
5.0
115.2
5.0
91.2
7.8
Cu
Fe
S
SiO~
CaCT
Other
308.6
308.6
255.0
200.0
54.7
46.4
                                     CALCINE
                                    FUEL
                              CONVERTER
                               SLAG
                               AIR AND
                               OXYGEN
°2
139.2
                                      BURNERS
                                                                        FUGITIVES
                                                                        SO,
                                                                        Cu<
                                                                        Fe
                                                                        S
10.8
 0.5
 0.5
 0.3
                                                 MATTE
                                                          SLAG
                                                                    CHARGING PIPES
                                                   MATERIAL BALANCE  IN TONS/DAY.
                                                   TONNAGES ARE FOR  CAPACITY OF UNIT.
                                                                                          OFF-GAS
         MATTE
                 S02  1153.0
1% VOL.
Cu
Fe
S
SiO?
CaO^
Other
308.6
308.6
255.0
200.0
54.7
46.4
                     Figure  20.   Material balance:   reverberatory furnace after fluid-bed roaster.6

-------
  MATTE
Cu
Fe
S
CaO
°2
315.5
238.5
168.7
3.7
63.4
(119.8)
(90.6)
(64.1)
(1.4)
(24.1)
SLAG
                                                                          FUGITIVES
so
2
31
6
.0
(1
20
.0)
4%
VOL.
               TUYERE
               PIPES
SQ0
Cu4-
Fe
S
11.0
0.5
0.5
0.2
(4.2)
(0.2)
(0.2)
(0.1)
Fe
Si09
CaO^
°2
Other
2.6
115.2
1.3
0.7
8.2
(1.0)
(43.8)
(0.5)
(0.3)
3.2
S
Cu
Fe
SiOp
CaO^
02
Other
5.0
12.0
239.1
115.2
5.0
91.2
6.9
(1.9)
(4.6)
(90.8)
(43.8)
(1.9)
(34.6)
(2.6)

7^
PNEUMATIC /^fe
PUNCHERS *%£
BLISTER COPPER
Cu
- Fe
Other
303.0
1.5
1.5
(115.0)
0.6
(0.6)
°2
190.8
(72.3)
                                                MATERIAL BALANCE IN TONS/DAY.
                                                VALUES  IN PARENTHESES  INDICATE CAPACITY
                                                  OF UNIT; OTHER VALUES ARE ON BASIS OF
                                                  303 TONS/DAY BLISTER COPPER.
       Figure 21.   Material  balance:   Peirce-Smith  converter after  fluid-bed  and
                                   reverberatory furnace."

-------
     FLUX
Fe 11.
S 2.
Si02 181.

PELLETIZED
CONCENTRATES
Cu 357.7 (431.7)
Fe 395.7 (477.6)
S 421.9 (509.2)
Si02 67.6 (81.6) FEEDER

02 331.5

7 (14.1)
4 (2.9)
6 (219.2)
SO~2J650~.7 (785.4) 6% VOL.

SQ2 FUGITIVES
Ohh-bAb ' "
CONCENTRATE / t \ ^°2 1?'?
i>f PELLETS AND FLUX / \HOOD Cu 0.4
w \ \ Fp n-*
r£ m 	 "*^ 	 L%s> 	 R S 0.3
VTt j-«miiiiiiiiiiiiiiiiiiiiiiiiiuiiiiiiiiniy- •Ulllllllllllllllllllllllllinllllimmi 1 nilDMrn
"* § -T^*^5^^- :,••.-. SETTLING c, Ar 7TTT1 TNr £
— '**^i'r*~^*'1~ptif?Lrtf^''r\~— OLnu OL 1 L L A1113 Bt -^^
AIR TIIYFRE ~~\^ Ffi 398.7
M1K IUTtKt ' REDUCING GAS ^ -|n q
(400.1) HIGH-GRADE MATTE Si°2 249'2
(14.8)
(0.5)
(0.4)
(0.4)

(51.0)
(481.2)
(12.4)
(300.8)
Cu 315.0 (380.2)
Fe 8.4 (10.1)
S 82.2 (99.2)
               MATERIAL  BALANCE IN TONS/DAY.
               VALUES IN PARENTHESES INDICATE CAPACITY
                 OF UNIT; ALL OTHERS ARE ON  BASIS OF
                 303 TONS/DAY BLISTER COPPER.
Figure 22.   Material  balance:   Noranda  continuous smelter.

-------
                    MATTE'
Cu
Fe
S
315.0
8.4
82.2
(233.0)
(6.2)
(60.8)
NO
so2
159.0
(117.5)
4% VOL.
                                                                                           FUGITIVES
                   SLAG
                               TUYERE
                               PIPES
SO-
Cu
Fe
S
1.2
0.1
0.005
0.1
(0.9)
(0.1)
(0.004)
(0.1)
SiO,
Fe Z
Other
25.5
0.6
2.3
(18.9)
(0.4)
(1.7)
Cu
Fe
S
SiO?
OthSr
11.9
7.5
2.0
25.5
0.8
(8.8)
(5.5)
(1.5)
(18.9)
(0.6)



/AVJi
PNEUMATIC /*£
PUNCHERS Mg?
^v
BLISTER COPPER


Cu
Fe
Other

303.0
1.5
1.5

(224.1)
(1.1)
(1.1)
°2
80.1
(59.2)
                                                                 MATERIAL BALANCE IN TONS/DAY.
                                                                 VALUES IN PARENTHESES INDICATE CAPACITY
                                                                   OF UNIT; OTHER VALUES ARE ON BASIS OF
                                                                   303 TONS/DAY BLISTER COPPER.
                  Figure 23.   Material balance:   Peirce-Smith  converter after  Noranda  furnace.

-------
u>
                                     DRIED
                                  CONCENTRATES














FUGITIVES
SO,
Cu^
Fe
S

14.5
0.5
0.7
0.6

S
Fe
Cu
SiO~
Ni e-
Other
499.6
467.6
330.6
64.1
1.6
93.1

AIR |
09 393.8
<-
^
\
\
jr —
                                                                       FLUX
Si02
Fe
Ni
Other
205.7
8.1
2.3
177.6
HIGH-GRADE
MATTE
Cu
Ni
Fe
S
Other
315.0
3.5
25.5
89.1
8.4
                                                                                        OFF-GAS    S02   773.1

                                                                                                 (10% VOL.)
                                                                                SLAG
                                    MATTE
SLAG HATTE
                                                               SETTLER
                                                  MATERIAL BALANCE IN TONS/DAY.
                                                  VALUES INDICATE CAPACITY OF UNIT.
Cu
Ni
Fe
S
SiO?
Other
15.1
0.4
449.5
16.1
269.8
262.3
                               Figure 24.  Material  balance:  Outokumpu  flash smelting furnace.

-------
MATTE
Cu
Ni
Fe
S
Other
315.0
3.5
25.5
89.1
8.4
(214.0)
(2.4)
(17.3)
(60.5)
(5.7)
    SLAG
                 TUYERE
                 PIPES
S
Cu
Fe
SiOp
Ni 2
Other
2.3
11.9
24.8
35.6
3.5
10.1
(1.6)
(8.1)
(16.7)
(24.2)
(2.4)
(6.9)
so2
171
.5
(116
.3)
4%
VOL.
                                                                             FUGITIVES
S00
Cu^
Fe
S
1.9
0.1
0.01
0.1
(1.3)
(0.1)
(0.01)
(0.1)
Fe
SiO?
Other
0.8
35.6
3.2
(0.5)
(24.2)
(2.2)
                            BLISTER COPPER
Cu
Fe
Other
303.0
1.5
1.5
(205.8)
(1.0)
(1.0)
°2
86.7
(58.8)
                                                   MATERIAL BALANCE  IN TONS/DAY.
                                                   VALUES IN PARENTHESES INDICATE CAPACITY
                                                     OF UNIT; OTHER  VALUES ARE ON BASIS OF
                                                     303 TONS/DAY BLISTER COPPER.
      Figure  25.   Material balance:   Peirce-Smith converter after Outokumpu  furnace.1

-------
                                      DRIED
                                   CONCENTRATES
Cu
Fe
S
Si 09
Ca(T
Other
308.6
308.6
379.1
102.9
5.7
38.4
(404.9)
(404.9)
(497.4)
(135.0)
(7.5)
(50.4)
                                                                         FUGITIVES
S00
Cu"
Fe
S
11.6
0.5
0.5
0.3
(15.2)
(0.7)
(0.7)
(0.4)
               CONVERTER
                 SLAG
*»
Ul
                                           OFF-GAS
                                              9
so2
238.
0
(310.
2)
5%
VOL.
Cu
Fe
S
Si 09
CaO^
Other
18.9
372.9
7.7
179.4
7.8
154.0
(24.8)
(489.2)
(10.1)
(235.4)
(10.2)
(202.0)
                                                          ELECTRIC
                                           FETTLING PIPES    POWER
                              ELECTRODES
CONVERTER
  SLAG
 LAUNDER
                                             MATTE
                                                                         CALCINE
Cu
Fe
S
CaO
Other
322.5
371.2
253.5
5.8
61.0
(432.1)
(487.0)
(332.6)
(7.6)
(80.0)
                                                     MATERIAL BALANCE IN TONS/DAY.
                                                     VALUES IN PARENTHESES INDICATE CAPACITY
                                                       OF UNIT; OTHER VALUES ARE ON BASIS OF
                                                       303 TONS/DAY BLISTER COPPER.
FLUX



Si Op
CaO
C02
Other
32.9
48.0
37.3
9.0
(43.2)
(63.0)
(48.9)
L(11.8)
                                                                                           SLAG
Air
°2
123
.9
(162
.7)
Cu
Fe
S
Si Op
CaO^
Other
4.5
309.8
9.1
315.1
55.7
140.4
(5.9)
(406.4)
(11.8)
(413.6)
(73.1)
(184.2)
                                  Figure 26.   Material  balance:   electric  smelting furnace.'

-------
           MATTE
Cu
Fe
S
CaO
Other
332.5
371.2
253.5
5.8
61.0
(95.4)
(109.8)
(75.0)
(1.7)
(18.0)
                        TUYERE
                        PIPES
       SLAG
Cu
Fe
S
SiO?
CaO
Other
18.9
372.9
7.7
179.4
7.8
154.0*
(5.6)
(110.4)
(2.3)
(53.1)
(2.3)
(45.6)
so2
474.5
(140.3)
3.5% VOL.
                                                                                                   FUGITIVES
S00
Cu*-
Fe
S
16.5
0.6
0.8
0.3
(4.9)
(0.2)
(0.2)
(0.1)
^Contains  02 80.4  (23.8)
                                                                                    325.9
                                  BLISTER COPPER
96.4)
Cu
Fe
Other
303.0
1.5
1.5
(89.6)
(0.4)
(0.4)
                                                                  MATERIAL BALANCE IN TONS/DAY.
                                                                  VALUES IN PARENTHESES  INDICATE CAPACITY
                                                                   OF UNIT; OTHER VALUES ARE ON BASIS OF
                                                                   303 TONS/DAY BLISTER COPPER.
Fe
Si 09
CaO^
Other
4.0
179.4
2.0
14.1
^1.2)
(53.1)
(0.6)
(4.2)
              Figure  27.  Material balance:  Peirce-Smith  converter after electric furnace.1

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                            SECTION 6

           CURRENT CONTROLS AND PROPOSED MODIFICATIONS


     Control of  fugitive  emissions  at copper smelters currently
consists  of application  of  certain  fundamental  control  prin-
ciples,  such  as preventive  maintenance,  use  of  hooding,  and
installation of emission collection systems at various stages of
the process.

     Most plants schedule periodic maintenance  of major equip-
ment and perform repairs  as needed to correct malfunctions.  In
addition  to these  practices,  preventive maintenance  would in-
volve  close  attention throughout the  daily  plant operations to
detect potential problems and to remedy defects  as they occur.
The goal is  to prevent catastrophic malfunction or upset,  which
not only  can retard or completely  curtail production,  but also
can cause the release of large quantities of fugitive emissions.
Programs of preventive maintenance should be geared specifically
to  the specific type of plant equipment, with  emphasis on pre-
vention or  leakage  from  roasters and furnaces through attention
to the condition of refractories, tight fit of doors and covers,
and all other areas of the unit that might allow leakage.

     The following  types  of  emission  collection systems are in
current use, either singly or in various combinations:

     Fixed secondary hoods

     Swingaway and movable secondary hoods

     Converter aisle  forced-exhaust system with baghouse (i.e.,
       enclosed building)

     Air curtains

     Roof monitors.

Table  2  briefly describes  the  design and operation  of each of
these  systems  and  lists  the typical  operating  and maintenance
problems that are encountered. Appendix B discusses air curtains.

     Some smelters  have introduced  innovative control equipment
and procedures,  and other  control  strategies are proposed and
under  investigation.   In  addition to descriptions of the common

                                47

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                                      TABLE 2.   SUMMARY  OF  CURRENT FUGITIVE  EMISSION  CONTROL  SYSTEMS
                 Type
     Design and operation
         Operational  and  maintenance problems
       Efficiency
00
          Monitor, natural
          (U.S.)
           Monitor, powered
           Fixed  hood with
           secondary emission
           ducting  (U.S.)
           Enclosed converter
           hood swing-away  type
           with fixed hood
           Enclosed building
Simple design;  relies  on  outside
air movement for removal  of  emis-
sions
Simple design; large air movement
required at fans;  removal rate is
constant
Clearance needed for crane hook and
cables during collar pulling or matte
additions; retrofit difficult for
ducting, fans, breeching,  and dust
bins; operational at all  times that
converters are on line; good face
and capture velocities required.

Clearance needed for crane hook and
cables during collar pulling or
matte additions (fixed hood).  Clear-
ance needed for floor space relative
to fixed hood; rugged drive mecha-
nism needed for swing-away converter
hood
Requires careful design of all open-
ings  (personnel, truck, rail, mate-
rials) to minimize air motion; roof
monitor must handle all ventilation
air for workers; building costs high
because of wind load design and need
for tightness and close fits
Haze in building during  emissions; outside air movement
affects time required to clear  the area; crane operator
and maintenance personnel  working above the converter
may be required to wear  face  aspirators; visible emis-
sions in the monitor area;  maintenance in the converter
area; EOT and roof trusses  for  removal of the settled
emissions other than gases.

Blind pockets or short-circuited  flows could cause haze
and emission buildup in  the roof  line area; crane oper-
ator may need to wear face aspirator at times; main-
tenance in converter area,  EOT  crane, and roof trusses
for removal of settled emissions  other than gases.

Operational damage to hood by swinging or uncontrolled
EOT crane action during  matte addition or collar pull-
ing; maintenance is less in the converter area, EOT
crane, and roof trusses
Space occupied in aisle by the swing-away  converter hood
when adding matte, rabbling, or skimming could  hamper
crane movements; crane must deposit ladles for  pouring
or skimming and at completion of the operation  must
await retraction of the hood before engaging  the  ladle;
maintenance of swing-away mechanism and minimal main-
tenance for removal of particulate buildup that occurs
during matte additions and rabbling

All openings must be maintained constantly against ex-
cessive air infiltration; light siding and roofing
required; air circulation within building  for the
workers and process must be carefully controlled;
intake and exhaust fans need preventive maintenance;
cleanup maintenance for settled particulates  in the
converter area is similar to that for a monitored
system, either natural or powered.
Dependent on outside  air
currents and inside air
motion
Dependent on number of
monitors, fan size,  build-
ing design above the con-
verter proper; air motions
Dependent on distance of  the
mouth of fixed hood from  the
emission source; also on
capture and face velocity
created by the fan at mouth
of fixed hood.
Dependent on operational
cycle; efficient during
pouring, blowing, or slag-
ging; efficiency similar  to
that of fixed hood during
matte addition or rabbling;
air motions influence ef-
ficiency in all operations

Dependent on building tight-
ness, air motion control,
monitor exhaust capabilities

-------
controls  in current  use  at copper  smelters,  this  discussion
presents suggested modifications and control measures that could
further  reduce  fugitive emissions.   Emphasis  is  placed  on  The
Peirce-Smith converter, a  significant source  of uncontrolled or
poorly controlled fugitive emissions.


HOODING SYSTEMS

     Emissions  of sulfur  dioxide  and particulate  from  copper
smelting are  contained to some extent by  hooding  systems.   All
of the  domestic smelters  are  equipped with primary  hoods,  and
some also  have  various types  of  secondary hoods, which  can be
very effective  over  reverberatory matte and  slag  launders.   At
some  smelters   the  slag  ladles  are  operated  within a  partial
enclosure with  a  hood  overhead to collect fugitives  during slag
discharge.  Swing-away hoods that are lowered to cover the matte
ladles during filling  are  used at some plants and are effective
while the  ladle is being filled.   When the filled ladle must be
removed from under this cover,  however, fugitive emissions arise
from the matte surface.

     Secondary  hooding systems  are  being  used also to partially
control  fugitives from  some Peirce-Smith converters.  At  some
smelters a fixed hood (Figure 28)  located above the sliding gate
is  used in  conjunction  with  the  primary hood during  blowing
operations.  Although  it  is  somewhat  effective  during the blow-
ing phases,  the hood serves little use  in controlling fugitive
emissions  when  the converter  is  in  the  "rolled-out" position,
i.e., when the  gate  is in the upmost position and the converter
is pouring  or receiving  charge.   Following are details  of  the
various hooding systems.

Fixed Secondary Hood

     In  the  United States the Phelps  Dodge  Corporation has  in-
stalled some fixed secondary hood units at their Ajo and Morenci
plants.  The configuration of  a fixed secondary hood depends on
the location of the converter relative to the crane runway gird-
ers,  the  configuration  of  the  primary  uptake  hood,  and  the
requirements for  maintenance and operation.  The  effectiveness
of  a  secondary  emission  control  system is  influenced  con-
siderably by these factors.   Air  movement in the converter area
and the  capture velocity at the  face  of  the  secondary hood are
also important.

     At  the  Ajo Smelter,  the atmosphere of the  converter  room
Is relatively cleanj the  crane operator does not wear a face
respirator.  Conditions of the converter aisles appear  to be less
satisfactory at some of the  other U.S. smelters not  equipped with
fixed secondary hooding.
                               49

-------
                                 TO  SECONDARY
                                   HOODING
                                  MAIN DUCT
Figure 28.   Secondary converter hood configuration,
                         50

-------
     Figures  29  and 30  show  the  overall ducting (approximately
210 m) of the secondary emissions system at Ajo.  Each converter
has two  secondary inlets,  one on each side of the primary hood.

     Each fixed  hood  (Figure  28)  is approximately 4 m long, 6 m
wide,  and  2 m high.   The hoods,  which  are  half-oval in cross-
section, are  affixed to the upper  front sides  of the converter
primary uptake hoods.  Each secondary duct handles approximately
68,000 m3/h at temperatures of about 93°C.

     Requirements  at the  Ajo  plant  cannot be regarded as appli-
cable to other smelters, whose layouts may necessitate different
quantities  and  configurations  of  ducting to  contain fugitive
emission effectively.

Movable Hoods

     Movable  secondary hoods  are  used   in  conjunction with a
fixed  hood at  several  primary  copper  smelters  in  the  United
States.

     A type of movable hood system that  could  be used for con-
trol of  converter emissions is shown in Figures  31 through 34.
The movable hood would be made of steel, elliptical in shape so
as to  fit  over the fixed hood with a clearance of 10 to 15 cm.
It would have its own track for movement.

     In  the  retracted position,  the  movable  hood  should not
extend  farther  horizontally  than  the  fixed  hood.   In  the
extended position,  it  would mate  with the lip of the fixed hood
to provide  continuity  of  ducting of secondary emissions.   The
movable hood  would have its own  retracting  and lowering mecha-
nisms,   which  would be  controlled  by  the  converter operator.

     The hood attached to  the gate  also would be a type of mov-
able hood.  The  gate  hood (Figures  33 and 34) would be of steel
construction  and possibly elliptically  shaped  to fit under the
movable hood  when in a retracted position.   Again,  as with the
movable hood,  the gate hood would be protected by the fixed hood
in its  up  position,  i.e.  no  part of  the  retracted gate hood
would  extend  horizontally  beyond the fixed hood  (Figure  34).

     In the extended position,  the  gate  hood would continue the
ducting of  secondary emissions to  the movable  and fixed hoods.

Swing-Away Hood

     A brochure  of the Nippon Mining Company shows a deflector
converter hood of the swing-away type with a retractable second-
ary hood  above   (Figure 35).   In  the foreground,  the deflector
hood is shown in the operating position during a blister copper
pour.  The  emissions  are  deflected into  the  retractable hood.


                               51

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                                                53.3 m
                                           (175  ft)  APPROX/
                                                   ELEVATION
                                                                               MATCH  LINE
                                                                                  a:
                                                                                   -
                                                                        SECTION A-A
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                                                                                        SHELTER

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               Figure 30.  Ajo  Smelter,  secondary emission collection system,  sheet  2  of  2.

-------
               SMOKE PLENUM
              SECONDARY DUCT
         (LOCATION SHOWN IS FOR'
           A LOW CRANE RUNWAY)
     MOVABLE HOOD
INDEPENDENTLY OPERATED
    AND TIED  INTO
    GATE MOVEMENT
                          SECONDARY DUCT
                             DUST BIN
                                                         TO COPPER
                                                           HEADER
                                                           TO FAN
                                                       SECONDARY DUCT
                                                          TO STACK
                                                       DAMPER CONTROL
                                                                INDEPENDENTLY
                                                                  OPERATED
                                                                 HOOD HOIST
                                                                  MECHANISM
   HOOD FIXED
    TO GATE
                                                      BIN ON TAKE AWAY
         Figure  31.
Side view of Peirce-Smith converter with hooding
           in position.
                                      54

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                            HOOD FIXED
                             TO GATE
r
                               CONVERTER
                                                     SECONDARY DUCT
                                                        DUST BIN
Figure 32.   Front view of fixed, movable, and gate hoods.

                            55

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EOT RUNWAY
    SECONDARY  HOOD
       DUST  BIN
                                                      SECONDARY HOOD DUCT

                                                        SMOKE PLENUM
                                                        SECONDARY HOOD DUCT

                                                      SECONDARY HOOD DUST BIN
XDUST  BIN
  MAIN  HOOD
      SECONDARY
      HOOD DUCT
                                                            MOVABLE  HOOD
                                                            MOTORIZED DRIVE

                                                          SWING HOOD DURING
                                                          TAPPING OR SLAGGING
                                                          POSITION
                                                       LADLE
           Figure 33.  Peirce-Smith converter with hooding extended.

                                       56

-------
   HOIST  DRUM
                       GEAR REDUCER
                                                 TO COPPER HEADER
                                                     TO  FAN	7
                        E.O.T. CRANE
                           BRIDGE
 ^/_j*v  \
&M/  ;
   £'S/v-j\/7 <»
   t'-.J^U^   C
                                             SECONDARY DUCT
                                               TO STACK
                                                  DAMPER CONTROL
                                                NOTE:
                                              INSTALL LIMIT SWITCH TO
                                              TRAVEL OF TROLLY FOR
                                              CHARGING OR COLLAR PULLING
                                              TO PROTECT HOODING:  FOR
                                              OTHER MAINT. WORK, ETC.
                                              REQUIRING THE HOOK TO WORK
                                              IN THIS AREA THE LIMIT
                                              SWITCH WILL ENERGIZE A GONG
                                              AND FLASHING LIGHT TO ALERT
                                              THE CRANEMAN AND CONVERTER
                                              OPERATORS THAT THE LOAD ON
                                              THE CRANE OR HOOK CAN
i                                              INTERFERE OR DAMAGE THE
                                              iOOD UNLESS THE HOODING
                                              [S RETRACTED.
                                                 BIN OR TAKE AWAY
Figure 34.  Side view of Peirce-Smith converter during collar pulling or
      blister copper ladle removal, with hooding retracted.
                                 57

-------
Figure 35.   Enclosed swing-away converter hood of Nippon  Mining Company.
                                    58

-------
      Movable hoods  must be retractable to a position  that  does
 not interfere  with  the overhead  crane  or plant operations  and
 that is  not subject to  abuse  from moving objects, such  as  the
 EOT  crane  hoist  block  or cables,  charging  ladles,  or   the
 collar-pulling rig.

      Some  operating procedures  and system  design factors  for
 secondary  hood  systems are  discussed below.  These procedures
 and designs  should  minimize damage, breakdowns, and delays  and
 should optimize working conditions for plant  employees.

      The movable,  swing-away,  and  gate hoods  should  be under
 control of  the  converter operator.  The EOT crane operator  and
 converter personnel  should be aware whenever  the  EOT crane hook,
 cables,  and hook load (ladle,  collar puller,  etc.)  pass  into  the
 area adjacent to the hoods  as  indicated at the Nippon plant  in
 Figure  35.   At such times  the trolley of the  EOT crane could
 trip a limit  switch to energize  an intermittent sounding horn
 and/or  flashing  lights on  the underside of the  EOT  crane  cab
 stairs.   These  warning  signals  would  operate  as long  as   the
 trolley of the EOT  crane  is  in the area of the hoods.  The horn
 signal  should be of such intensity  and sound  as to be distin-
 guishable from other EOT  crane or  maintenance sirens.  Whenever
 this sound is heard, one  of  the  converter personnel would check
 to  see  what hoods may need to be  retracted.

     At the end of  each shift, the departing EOT crane operator
 would  check the warning or interlock  system by a trial  run  of
 the  trolley into this converter area and record its condition  on
 his  daily check list.   Before putting  the EOT  crane into ser-
 vice,  each  incoming crane  operator would  also check  out  the
 warning system.

     For  matte  additions  and collar  pulling  procedures,  the
 converter operator would position  the converter gate and retract
 all  the hoods.  After the  matte addition, the converter would  be
 rotated to  its blowing position in  the  primary converter  uptake
 hood.   All  hoods  would be extended  into position; blowing would
 commence,  and  flux  could be added  to the converter as required.

     For  slagging or  skimming operations, the  swing-away hood
 would be  retracted.   In  the event  of  interference between  the
 EOT  crane hook or cables  and  the  gate  hood, the gate  hood too
 must be retracted.   After the  ladle is  removed or repositioned,
 the  EOT crane  would be  backed off  and the appropriate  hoods
 positioned  in  place.  The same movements  of  the hoods  would  be
 required  in  blister  copper  pouring  for the  positioning   or
 removing of a ladle.

     Positions  of  the  secondary  hoods  during the  various con-
verter  operations are  shown in Table 3.  Estimated efficiencies
 of  the  different  types  and combinations  of hoods during  the
various converter  operations are  shown  in  Table  4.  The  valves

                                60

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                          TABLE 3.   POSITIONS11 OF MOVABLE HOODS
Type
Movable
Gate hood
Swing- away
Matte
addition
Retracted
Retracted
Retracted
Blowing
or
holding
Extended
Extended
Retracted
or in
operating
position
Skimming
Extended
Extended
Operating
position
Rabbling
Partially or
fully extended
Partially ex-
tended
Retracted
Collar
pulling
Retracted
Retracted
Retracted
Pouring
Extended
Extended
Operating
position
Definitions of hood positions:

   Retracted - hood in its highest or extreme position away from the converter.
   Extended - hood in its lowest position.
   Partially extended - hood extended as far as practical to maximize secondary emissions
                        control.

-------
KJ
                          TABLE  4.   PEDCO'S ESTIMATED RETROFITTED HOODING EFFICIENCIES'
                                               (values in percent)
Hood type
Fixed
Fixed and movable
Fixed and swing- away
Fixed, movable, and swing- away
Enclosed building
Matte
or
hot metal
addition
30-50
30-50
30-50
30-50
50c-95
Blister
or
hot metal
pouring
30-50
40-70
80-90
80-90
50c-95
Skimming
or
slagging
30-50
40-70
50-70b
60-80b
50c-95
Blowing
60-70
70-90
80-90
80-90
50c-95
            Most system efficiencies would be higher if air motion (i.e.,  open doors,  man-cooling fans,
            monitors, etc.) could be eliminated.   Skimming is removal  of slag from the converter by
            tilting of the converter.   Slagging is removal of slag from the converter  by tilting of the
            converter and manual use of a rake to work the molten bath.

            Efficiency during slagging would be similar to that in blister pouring.

          c Low efficiency due to air motion; with inadequate design of monitors and airflow,  efficiency
            could be as low as 75%; with doors left open efficiency could drop to 50%.

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for  collection  efficiency are based  on  retrofit installations.
Collection  efficiencies  would  be greater  if the  installation
were incorporated into design of a new plant.


ROOF MONITORS

     The standard design  in  buildings where emissions can cause
operational problems usually consists of monitors at the peak of
the  roof.  A monitor  runs the length of building to permit con-
vective  removal of  the  emissions,  which  rise  slowly.  As  an
alternative,  smaller  fan-powered monitors  are  sometimes  in-
stalled above each emission source.

     As the  emissions drift upward,   they may  impair the visual
or  respiratory  functions  of the  EOT crane operator;  for  this
reason he  may  wear respiratory  equipment or the EOT crane cab
may  be  air conditioned.   The heavier particles  usually settle
out on process equipment such as the  primary uptake  hood and EOT
crane, and on structures such as runways and roof trusses.

     Fugitive emissions  may  cause buildup  of haze  in the upper
portion  of  naturally ventilated buildings.   Even  if powered
monitors  are  used,  pockets  of  dead  air and  haze   may form at
certain locations.

     These monitors  could be tied into  a  collection system by
enclosing the sides of the roof monitors and ducting to induced-
draft fans and  baghouses.  The  powered monitor units could also
be enclosed and ducted similarly.


BUILDING ENCLOSURE

     Because of the  problems with  the  currently  used hooding
systems,  which  are  ineffective  when  the converter is pouring or
receiving  charge,  the concept  of total  building enclosure has
arisen.    One  smelter  is  experimenting with total  enclosure of
the  converter  building,   discharging  the fugitive  emissions by
means of a powered roof monitor system.  This approach, however,
entails some problems.  Currently, only  three of the five sec-
tioned roof monitors  at  this smelter are powered; the other two
sections are gravity-type  monitors.   Also,  when building access
doors are left in the open position,  the design concept of total
building enclosure  is not realized.   With  proper design, main-
tenance,   and  cooperation of  plant   personnel,  collection  of
converter  fugitive  emissions by  total  building  enclosure could
be very effective.  Proper design would involve such factors as
tightness  of  the  building, capacity  of  the  takeaway  fans,
movable truck and rail doors, lighting, and ventilation through-
out  the  entire  building  to  ensure worker safety.  Maintenance,
                               63

-------
 particularly of the air moving  equipment,  would be  important to
 minimize problems with system ventilation  imbalances.  Training
 and daily performance  of  employees would  be  very important to
 ensure that  doorways,  louvers,  or other  openings are  kept closed
 at all  times  when not in  use.   Such careful practice by plant
 personnel would minimize disturbance of  airflows.

      The merit  of  total  converter  building enclosure  is the
 possibility  that  such  a system could capture nearly all of the
 fugitive emissions.  The  scheme entails several problems, how-
 ever.   Design of  a total  evacuation  system  that could provide
 the proper air changes in all  working areas would be difficult.
 Even with an  all-powered roof monitor  system  to  pull the air
 through the  building, pockets of dead  air are  likely, especially
 in corners and around objects that obstruct the  airflow.  With a
 totally enclosed  building,  air movement must be properly dis-
 tributed,  even in  the  difficult areas  such  as  around the con-
 verters,  crane  runways-, EOT crane  repair  areas,  and  converter
 aisles.   Building access  doors  and mandoors  must  be opened at
 times  to permit movement of.  materials  and  personnel.  Proper
 ventilation  of a  totally  enclosed building may  require the use
 of air ducts to  convey  air to specific locations.  Such a system
 would  be  "short-circuited"  by  passage of air through opened
 doorways,  and disruption  of the  airflow patterns  would reduce
 the  effectiveness  of  the  ventilation system  in removing fugi-
 tives  and changing the  building  air.

     Other problems with total building  enclosure are difficulty
 of retrofit  and high cost.  Building structure  and support may
 have to  be reinforced to handle  the  stress  of  added side and end
 walls  and  a  roof  monitor  system.   Capital  cost  of totally
 enclosing an  existing  converter building  could be  very high.
AIR CURTAINS

     Mitsubishi  Metal Corporation  at Onahama,  Japan,  controls
some of  the  fugitive emissions from a Peirce-Smith converter by
the use  of secondary hooding  and  an air curtain.   (Details are
given  in  Appendix B. )   This  technique  could be  modified for
application to multihearth roasters, reverberatory furnaces, and
other smelter process equipment.

     Fugitive emissions at the Onahama smelter are controlled by
a combination  of secondary  hooding,  air curtains,  and building
enclosure and evacuation.  Visual observation indicates that the
system is  80 to  90 percent effective.  With additional building
evacuation, a 90 percent capture level could be maintained.  The
present  system  does not  impede  converter operations.  Although
visibility from  the EOT crane cab  is  not seriously impaired by
                               64

-------
gases  and particulate,  additional building  ventilation  could
improve  visibility and  reduce potential  exposure  in the  EOT
crane cab.

     A  proposed  secondary hood  system incorporating the  air
curtain technique (Figure 36)  would consist of steel side panels
with  a back  and top panel,  forming  a partial  enclosure.   The
front,  or side  at which  the  crane with  ladle approaches  the
converter, is  open.   The  top  panel would have  an  opening suf-
ficient to permit cables from the EOT crane to pass  into the en-
closure  without  damaging  the  structure  or  crane   cables  when
charging  matte,  removing ladles of slag  or blister  copper,  or
performing other operations.

     Air  is  blown from  one  side of the  top panel  opening and
collected on  the other side  of the opening.  The air flow rate
across the opening is 1000 Nm3/min.  The air entrains the rising
fugitive  emissions,  then is discharged to  a  collection system.
                               65

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                        MAIN HOOD

                              AIR CURTAIN
SIDE VIEW
               
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                            SECTION 7

        PROPOSED ALTERNATIVE CONTROLS AND PROCESS CHANGES


     This  section  describes  some  of  the  alternative  process
technologies  that  could  reduce  the   fugitive  emissions  from
copper smelting operations.  One alternative system involves the
use of  a cascading arrangement, in which matte  from  a smelting
furnace  (Noranda,  Outpkumpu,   electric  arc)   is  discharged  by
gravity via  launders  with hoods to a holding  furnace,  and then
by gravity via launders or runners to a Hoboken converter with a
swing-away  secondary  hood  (for use  during slagging  or blister
copper  pouring).   Another  alternative  is  use  of  a  furnace
similar  to  a  Q-BOP furnace in the steel  industry.   Emissions
from ladles  could be  controlled by use of an  EOT crane evacua-
tion system  or by use of bottom-pour ladles with covers.  These
and other possible means of fugitive emissions  control are de-
scribed below.
CASCADING SYSTEM, STAGGERED SYSTEM, AND INDUCTION PUMPING

     A cascading system, unlike  other systems discussed in this
section,  would  require a  change  in  the  traditional  smelter
layout  but  should  nearly  eliminate  all  sources  of  fugitive
emissions.  In a cascade smelter design the roasters (if used),
smelting  furnaces,  converters,  and anode or  refining  furnaces
would be arranged to receive products or slags by way of covered
launders, runners,  refractory-lined pipes, or similar equipment,
without  the  use of  ladles  (Figure 37).  Green feed would  be
transported to  the roasters, and  calcined  feed  would be screw-
conveyed or possibly conveyed pneumatically to a storage bin and
then to  a smelting  furnace.   Matte could flow  by  gravity from
the smelting  furnace to a  holding  furnace and then  to  an anode
furnace.  The  furnaces would be  arranged in a  stepped  manner.
Slags from the smelting furnaces could be tapped and disposed of
as is currently done.

     A cascading system would require  the  lifting  of raw mate-
rials a  considerable height and would  require  a building some-
what higher and  wider in some areas  than those  in  current use.
It also  would require additional  energy  to  transport the mate-
rials initially to a higher level.  Operational procedures would
be changed  in that  less movement of  the  EOT  cranes would  be
required.   The use  of  intermediate holding  vessels would  be

                                67

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Ol
CO
                   SUPPLE-
                   MENTAL
                   FUEL AND
                   BURNER
                        STORAGE
                          BIN
                         FROM
                        ROASTER
\       \
  N.       X
            v
    EMERGENCV !
    ALTERNATE
    LAUNDER.
                                                                                                                           SCHEMATIC
                                                                                                                           CASCADING
                                                                                                              ANODE WHEELS    SYSTEM
                                                   Figure  37.   Cascading  gravity  flow.

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expanded,  and  furnaces  would be  aligned in  a fanning  layout
rather than in  rows.   Transportation from unit to  unit would be
by  launders,   except  for  charging  to  the  first  unit in  the
process.  Maintenance  and operations  could be  somewhat restric-
ted  by the proximity  of the  various process  flows.   Overall,
control  of  emissions would be  facilitated by the holding  fur-
naces  and elimination of the  EOT  crane  for transport,  which
would eliminate process holdups.   A pendant floor-controlled EOT
crane  would be installed over each process  furnace  for  use in
emergencies and for cleanup,  repairs, and maintenance.   Such a
system using evacuated canopied hoods (Figure 38) would minimize
fugitive emissions.

     In  operation  of a new smelter  designed with  the cascading
arrangement,  problems  would  arise because of  the  new operating
techniques.  Moreover,  one could expect buildup of  accretions in
the  transfer  launders,  and similar  operating  problems.   Such
difficulties  are  common in  operation of  systems  based  on new
technology;   with   a  problem-solving   approach,   the  system
designers and operators could determine and implement the needed
modifications.

     As  an alternative  to  the  cascade  design,  a  horizontal
layout could be designed  for  use with induction pumping to move
hot  fluids vertically  or horizontally without the  use of ladles
and without open exposure of  the fluids.  The induction pumping
would require large  expenditures  of power to move  the materials
from one point to another,  but  control of gases and fugitive
emissions could be achieved with  the relatively simple control
equipment.   The envisioned  fugitive emission  control  system
would consist of hooding  at  the  transfer points with the neces-
sary ducting,  fans, and baghouse (Figure 39).

     Operation  of  the  induction pumping  system  would require a
building similar in height to the current structures but slight-
ly wider.  The  basic process  furnaces would be at ground level,
as at  present.  Again  the furnaces would  be arrayed  in a stag-
gered pattern rather than in a line.  The operator  would control
the  flow  to and from adjacent holding vessels; EOT cranes would
not be needed  for  handling  of ladles,  as with the cascade sys-
tem,  an  EOT  pendant  floor-controlled crane  over  each furnace
would be used for cleanup,  repairs, and maintenance.   Control of
the  process  and of emissions would be  facilitated,  but power
consumption,  equipment costs,  and maintenance requirements would
be greater.
OXYGEN ENRICHMENT

     When a Peirce-Smith converter is blown with air, the oxygen
in  the  air  reacts  with  sulfur  in  the  matte  to  form  S02  and
liberate heat.  Besides  removing the undesirable sulfur as S02,


                               69

-------
MENTAL X-'TWAS™
FUEL AND    ~r<^
BURNER     f-  •*
 STORAGE BIN
 FROM ROASTER
     FEED
       BIN
     CONVEYOR
       SLAG
       LADLE
                                                                                                 SCHEMATIC
                                                                                                 CASCADING
                                                                                                  SYSTEM
Figure  38.
                                                                                     ANODE WHEELS
                              Fugitive emission collection  system for  cascading  gravity  flow.

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             STACK
             STORAGE
              BIN   V | xi
             FROM    ^JC-'
             ROASTER
                                                                                               HYDROGEN
                                                                                              CONVERTERS
                                                       /ELECTRIC
                                                          ARC
                                                         FURNACE
                                                         (EAF)
                        /XFEED PORT
                              BIN
                            CONVERTER
Figure 39.   Fugitive  emission collection system for cascading/induction/gravity  flow.

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 oxygen also reacts with iron  in  the  presence of silica to form
 the  slag.   Large  amounts-of  air must  be blown into the converter
 to provide enough oxygen for  these reactions.  The blowing rate
 also must  be  high enough  to produce  the blister  copper  in a
 designated time  cycle.   Release  of  fugitive emissions through
 clearances,  such  as that between  the  primary  hood and converter,
 depends  partially on blowing rate, the emissions increasing with
 increasing rate of blowing.

     With  oxygen  enrichment, the blowing rate to a Peirce-Smith
 converter  could be reduced,  with  resultant reduction of fugitive
 emissions.   Enrichment  of  blowing  air  with 5  percent  oxygen
 would  theoretically allow  reduction of  a 68,000  m3/h blowing
 rate by about 2700 m3/h.   In  addition  to reduction of fugitive
 emissions,  the reduced blowing rate  of  air with higher concen-
 trations  of oxygen also increases the  S02  concentration  in the
 gas  stream to  an  acid plant.


 Q-BOP  FURNACE

     The  Q-BOP (Figure 40)  furnace  used in  the  steel industry
 could  be  applied  as  a converter  furnace at a  copper plant,  with
 oxygen or  Q2-enriched air as the  blowing medium use.  Use of the
 Q-BOP  furnace  in  the steel  industry  has  both increased produc-
 tion and  reduced  production costs.   In addition to these advan-
 tages,   the Q-BOP  can be operated in  an  enclosure or "doghouse"
 to prevent escape of  fugitive emissions.  Such  a  furnace  with
 fugitive emissions control  system is installed and operating at
 the  South  Chicago District of  Republic  Steel  Corporation.   A
 schematic  of that furnace and its gas cleaning  system is shown
 in Figure  40.   Where open  hearth (reverberatery type) furnaces
 were used  without oxygen enrichment,  the production rate was 23
 Mg of  steel per hour;  with  oxygen enrichment production rose to
 40 Mg  per  hour.   With  the Q-BOP  furnace,  production has  in-
 creased to  163 Mg  per hour.

     Secondary  emissions still   must be  controlled  around  the
 other  process  furnaces.   Use  of  this system  at  copper smelters
might  permit  the use  of   fewer   converters  and  could yield  a
 stronger S02 stream,  but would require holding furnaces for good
process  control.   Because  refractory lining  would  be required,
two  units   would  be  needed to   maintain  continuous  operation.
Maintenance  requirements  would   be  somewhat  greater with  the
refractory-lined  unit,  in  which temperatures may be  slightly
higher.  The building structure  could be  smaller than those in
current use.
                               72

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 FURNACE
ENCLOSURE
SECONDARY
  HOOD
ALVE
7 	 '
\

\
^SCRUBBER
    STACK
                                                    INLET
                                                    DAMPER
                               QUENCHER

                            GAS CLEANING SYSTEM
                                                I.D.  FAN
       Figure 40.   Q-BOP furnace  enclosed  in a  "doghouse"  to  prevent
    fugitive emissions  (from  Iron and  Steel Engineer,  November  1978)
                                     73

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 CRANE EVACUATION OF LADLE  EMISSIONS

      The  EOT  could be modified  to  minimize fugitive emissions
 from ladles during  transport,  filling,  and pouring by use of a
 capture  hood  fixed  to  the spreader  beam (Figure 41).  The cap-
 ture hood  would  also  be  fixed  to  a  sectionalized  telescopic
 column,  similar to  that used  in  the steel industry's stiff leg
 EOT  crane  for  moving ingots to  and from  a  soaking pit.

      An  exhaust  fan would  be  mounted on  the  trolley and con-
 nected with  ducting to  the telescopic  column duct.   The EOT
 crane would position itself over the ladle  or slag pot and as
 the  molten materials  are  discharged into the  receptacle,  the
 evacuation blower  on the trolley  would draw the emissions to the
 trolley  deck.   This  stream could be discharged to the overhead
 building monitor or ducted to  the crane walkway and  then to the
 building  column line for  discharge  to a collector system.  The
 evacuation system would operate during transportation and pour-
 ing  of the ladles.   Maintenance  requirements could  be  high if
 the  telescopic unit were damaged  by  poor crane operations.


 FLOOR-OPERATED CHARGING

      A  floor-operated charging machine,   illustrated in Figure
 42,  could  replace the EOT  cranes that transport ladles of matte
 or  slag.   A charging machine could  lift  a ladle of matte, move
 back and pivot 180 degrees, then move the  ladle of matte to the
 converter.  The arms would life the  ladle  to the desired height
 and  tilt  it for discharge  of the matte into the converter.  The
 converter  would be  contained  or  totally  encapsulated within a
 hood to  capture the  fugitive emissions.   A portion of the hood
 for  the  converter would be retractable for maintenance when the
 EOT  crane  must be  used.   Use of  the  floor-operated charging
 machine would  be limited to new  installations and the converter
 aisle would be wider than  those  in  the present converter build-
 ings.

     Emissions  escaping the primary hood would be  ducted from
 the  top  of the  encapsulated  structure.    This  floor-charging
 technique  would  minimize   fugitive  emissions  in  the converter
 aisle during charging.
TOP-COVERED BOTTOM-POUR LADLES

     Whether  EOT  cranes  or  charging  machines  are  used,  the
transport of molten  materials  by means of open ladles generates
visible  fugitive  emissions.   These  ladle  emissions could  be
reduced by use  of fitted covers that could be  placed on or re-
moved  from  the  ladle with minimal  effort (installation  of such
covers could pose some problems at some existing plants.)


                               74

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                                               FAR SIDE - ID FAN
                                                                   AUX HOIST  DRUM
                          TRANSFER
                           DUCT
                 TELESCOPIC CAPTURE
                  DUCT (SIMILAR TO
                 STEEL MILL SOAKING
                    PIT CRANE)
-J
m
                                                                         SPLIT RUBB
                                                                          COVER OVER
                                                                            NSFER DUCT
                   TRANSFER  DUCT
                     TO FAN
                   AND BAGHOUSE
                   (CAN BE MOUNTED
                   OVERHEAD  UNDER
                   THE ROOF  TRUSSES)
                                                                                         BLDG
                                                                                        COLUMN
                                                                                                     HOIST
                                                                                                     DRUM
                              'CAPTURE HOOD
                                 FIXED TO
                               SPREADER BEAM
                                             LADLE
TRANSFER
 DUCT
                                                                                                                       E.O.T.
                                                                                                                       GIRDER
                                                                                                          TELESCOPIC
                                                                                                            CAPTURE
                                                                                                             DUCT
                                         Figure 41.   EOT  crane with  telescopic stiff  leg.

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Figure 42.   Modified charging machine.

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     In  conjunction  with covers,  a specially designed  bottom-
pour ladle  with  stopper  rods  (similar  to that  in Figure  43)
might be  used at some  smelters for transport of  molten metal.
Such a  ladle,  with an  autopour unit attached to  the  EOT crane
(Figure  43),  is  used  in the  steel  industry,  and  the autopour
unit controls  the operation of  the  stopper rod mechanism  when
the  steel is  transferred  into  a  mold or  tundish, etc.  At  a
copper smelter the EOT  crane  operator  could control the flow of
matte directly  into  a converter furnace or the flow  of blister
copper into  an anode furnace.   With a cover over  the ladle or
the use of an overhead crane equipped with an evacuation system,
fugitive  emissions would  be  greatly  reduced.   A  bottom-pour
ladle could  be  seated on a ladle support,  and the ladle tapped
into a  specifically  designed opening in the end of a converter
through  a  refractory-lined airtight  joint/cover.   In  such  a
system,   the  mouth of  the converter could be made  smaller;  it
would be used solely for pouring and not for receiving.


INDIVIDUAL FURNACE ENCLOSURES

     In  another  fugitive  emission control  scheme,  each furnace
(e.g. a  Peirce-Smith converter)  would be  operated in  its  own
enclosure (Figure 44),  with  separate exhaust systems that could
tie  into  a  central point.   For each furnace an EOT crane would
be remotely  controlled  by  an operator outside of the enclosure;
during maintenance the operator would enter the enclosure at the
platform  levels  and  would use  the  captive EOT crane for main-
tenance  around the furnace.   Matte,  slag,  and blister copper
ladles would be  transferred  to  and from  the  enclosure via  a
four-wheel  rail-mounted  car,  also  remotely-controlled,  that
would pass through a sliding door.

     Individual  furnace  enclosures  would  require  the  use  of
closed-circuit  television.    Gas evacuation  systems  would  be
provided  to  handle the fugitive emissions from  each furnace.
Such individual  furnace enclosures  offer  a major advantage over
total  building  enclosure  in  that  emissions  do  not  spread
throughout  the building and  can be better controlled.   Also,
with separate  furnace enclosures all of the building air is not
evacuated, but only that  needed to remove fugitive emissions to
provide the required air changes in the smaller enclosure.

     Maintenance  requirements  would be greater than in current
systems,  and  failure  of a captive EOT crane would require rapid
remedial maintenance.   Another problem would be supplying proper
ventilation within the  area during maintenance if the unit is on
stream.    It  is  envisioned,  however,   that the  operator would
usually work outside of the enclosure and would observe the area
by  means  of  closed-circuit  television.   Emissions  would  be
minimal.
                               77

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 Figure 43.  Hydraulic cylinder mounted on barrel of ladle rigging
  raises and lowers stopper rod to control flow of molten steel
 from ladle to ingot mold.  (Courtesy, Blaw Knox Equipment, Inc.)

    From The Making, Shaping, and Treating of Steel by United
States Steel.  Copyright  (c) 1971, United States Steel Corporation.
Used with permission of United States Steel Corporation.
                                78

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             ENCLOSURE
                                                        FUGITIVE
                                                        EXHAUST
                                                          DUCT
                             REMOTE AND
                              PENDANT
                              OPERATED
                              CAPTIVE
                               CRANE
                                                   ENCLOSURE
                       POSITION
                       CHARGING
                        MATTE,
                         ETC.
ENCLOSURE
    JIB BOOM TO
 REMOVE LADLE COVER
REMOTELY CONTROLLED
                           CONVERTER
                          IN POSITION\
                              FOR
                           CHARGING
  LADLE
  COVER
                                                    TUYERE PUNCHER
                                                       MANUAL OR
                                                  REMOTELY CONTROLLED
   SLAG  OR
   BLISTER
COPPER LAOLE
  POSITION
                                           STEEL CURTAIN
                                              DIVIDER
                         CABLE PULLER OR
                       CABLE  REEL  MOTORIZED
                           TRANSFER  CAR
ENCLOSURE
          Figure 44.  Individual furnace enclosure.

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                            SECTION 8

                           REFERENCES
1.   Anonymous.  Surface Mining and Our Environment.  U.S.
     Department of the Interior.  U.S. Government Printing
     Office, Washington, D.C., 1967.

2.   Hayashi, M., H. Dolezal, and J.H. Bilbrey, Jr.  Cost of
     Producing Copper from Chalcopyrite Concentrate as Related
     to S02 Emission Abatement.  U.S. Bureau of Mines, RI 7957,
     1974.

3.   Coleman, R.T.  Population Control and Heat Recovery from
     Non-Ferrous Smelters.  Vol. II.  Radian Corporation.
     Austin, Texas, 1977.

4.   Bailey, J.B., et al.  Oxygen Smelting in the Noranda
     Process.  Presented at the 104th AIME Annual Meeting, New
     York,  February 1975.

5.   Harkki, S.U., and J.T. Juusela.  New Developments in
     Outokumpu Flash Smelting Methods.  Presented at Annual
     Meeting, AIME, Dallas, February 1974.

6.   Background Information for New Source Performance Stan-
     dards:  Primary Copper,  Zinc,  and Lead Smelters.   U.S.
     Environmental Protection Agency, EPA-450/2-74-002a,
     Research Triangle Park,  N.C.,  October 1974.
                               80

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                           APPENDIX A

                          COST ANALYSIS


     Detailed cost estimates are given for secondary hooding and
air curtain controls.  Brief  summaries  are given also for rela-
tive  costs  of other  alternative  control  systems  and estimated
energy  requirements.   The measurements  cited  are  in  English
units, as in the original cost studies.


COSTS OF SECONDARY HOODING SYSTEMS FOR CONVERTERS

     This section  is  a capsule discussion of  costs  of the fol-
lowing major types of secondary hoods:

     0    Fixed type:   made of structural steel with an ellipti-
          cal cross-section.   It  is  attached  to  the primary or
          uptake hood.

     0    Fixed and movable:  consists of a movable intermediate
          hood and a  hood  fastened to the gate.  Both hoods are
          made  of  structural  steel  with  elliptical  cross-
          sections so that they telescope in the retracted mode.

     0    Swing-away  type  with  fixed  overhead hood:  made  of
          structural  steel,  refractory lined,  and  supported by
          pivot arms  with  a motorized drive to permit position-
          ing during blowing and pouring operations.

     0    Combination  of  fixed  and movable   swing-away  type.

Cost Parameters

     This section  describes the various  items that  must be in-
stalled  or  modified  to  achieve  control  of  fugitive emissions
from the  Peirce-Smith converter,  source  of  a great quantity of
secondary emissions.  It does not include costs of certain oper-
ating procedures  that would minimize fugitive emissions, e.g.,
maintaining minimal  clearance  between  the  primary  uptake hood
and  the  apron  of  the  converter,  or maintaining proper matte
charges to  provide for  direct  flow of gases  from the mouth of
the  converter to  the centerline of  the primary  uptake hood.
                                81

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      Following  are descriptions of the items evaluated.

      0    The  fixed  hood has  an  elliptical cross-section of 17
          feet  6 inches  on the  major axis  and 7  feet  on the
          minor axis;  it is 9 feet 6 inches long.  The plate is
          3/8-inch  carbon  steel,  with  stiffeners  of  7-inch
          channels.   The fixed hood is  bolted to  the  primary
          hood  and to  the  smoke  plenum  of the secondary duct
          system.

      0    The movable hood in  the  retracted position is parked
          above the   fixed  hood.   It  has an  independent track
          system  with a  five-speed,  double-grooved  hoist unit
          and slack  cable  limit  switch.  The  movable head is 9
          feet  long  and is elliptical, with a major axis of 18
          feet  6  inches  and  minor  axis of  7 feet  6  inches.
          These dimensions  provide  a 3-1/3-inch  clearance be-
          tween the  movable and  fixed hoods.   There are mating
          plates  on  the  lower end of the fixed hoods and on the
          top of  the movable hood.  The lower end of the movable
          hood  is  fitted  with a  12-inch  thick  asbestos-type
          curtain that  follows  the  elliptical  perimeter to form
          a  seal  with the  gate hood.  The  movable  hood is con-
          structed of 3/8-inch carbon steel  with stiffeners of
          7-inch  channels.

      °    The gate  hood  is elliptical in  cross-section  with a
          major axis  of  16  feet 6 inches and  a minor axis of 6
          feet  6  inches;  it is 9  feet  long.   Clearance between
          the fixed hood and the gate is thus 3-1/2 inches.  The
          hood  would  be bolted  to  the  gate.   The place  is
          3/8-inch carbon steel reinforced with 7-inch channels.

     The  dimensions   listed above  would  be  modified  for each
converter  layout to  provide  the required  clearances.   Design
considerations  may dictate  that  the  fixed hood is  the  largest
unit, with the movable hood under it and the gate hood under the
movable hood.

     0    If height of the crane runway rail presents a problem,
          the smoke plenum  of  the secondary hooding duct system
          could be fitted as follows:  The plenum would span the
          primary uptake  hood  and  would  have  a  secondary hood
          dust  bin affixed  on  each  end.   The dust bins would be
          equipped with  pneumatic   dust  valves  and  discharge
          pipes.   This  evaluation   includes   no  provision  for
          removal of  dust in the dust bins.   The  smoke  plenum
          for this  study is  4 feet  by  4  feet 8 inches  by 21
          feet.    It is constructed of 3/8-inch steel with 6-inch
          channel stiffeners.
                               82

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     0    The secondary hooding duct system would have an uptake
          from each dust bin  adjacent to the converter and then
          pass to  its main  ducting  header  for  fugitive  emis-
          sions.    The  damper valve  shown would be  adjacent  to
          the main ducting header and would be  closed when the
          converter  is  out   of  service.   Existing  facilities
          would determine the path of retrofit.  The gases go to
          a  dust  bin  ahead  of the  fans  and from there  to the
          breeching into the  main  converter  gas duct and to the
          stack.    For  this  study,  the  main duct runs  are 600
          feet long.

     0    The fans considered in this estimate are Buffalo Forge
          Type 1320  BL,  single  inlet,  Arrangement  1,  Class  3,
          with 145 bhp, 785 rpm,  80,000 ft3/min at 200°F.  There
          would be one fan for each  converter  in the plant;  as
          many fans as are required would be tied into the sys-
          tem.

     0    Support  items  for  this  system include piping, wiring,
          foundations,   supports  for  ducting  every  20  feet,
          expansion joints,  miscellaneous platforms,  and walk-
          ways.  Valves,  fans, dust bins, and similar items are
          flanged  for ease of maintenance.

     The retrofit  factor was  considered as being midway between
a  new  installation  and an  existing  "difficult" installation.

     Estimates of  total installed costs  are  based  on current
(1978)  costs  for  major components  of specified  sizes,  as pro-
vided  by equipment suppliers.   Estimates of  fabrication costs
and installation in the  southwest are based on general accepted
engineering  practice   (e.g.,   as  given  in Richardson's, Mean's,
the Chemical  Engineering Index,  and  K.  M. Guthrie)  and on data
from PEDCo engineering files.

     A 5.0 percent contingency factor is  applied to the total of
the direct and indirect  costs to allow for changes in equipment
or design  changes.  An  escalation factor of  7-1/2  percent per
year  is used  to   account  for increases  in  cost  of equipment,
labor,  and  services   before  and  during  construction.   Direct
capital costs include  equipment,  instrumentation, piping, elec-
trical,  structural,   foundations,   site  work,   insulation,  and
painting.   Indirect capital  costs  include  engineering costs,
contractor's  fee   and  expenses,   interest (accrued  during con-
struction on  borrowed  capital-estimated at 9 percent per year),
freight, offsite expenditures, taxes (sales  tax of 4 percent of
equipment cost),  startup or shakedown, and spares.

     Annualized  costs  include  both  operating costs  and  fixed
capital charges:   utilities,  labor and fringe benefits, mainte-
nance,  plant overhead and total  fixed  costs,  which amount to


                               83

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 19.97 percent of total installed  costs  and consist  of deprecia-
 tion over  15  years at 6.,67 percent unless  otherwise indicated,
 property insurance at 0.3 percent, property taxes at 4 percent,
 and interest on borrowed  capital  at 9  percent.

 Capital Costs

      Table A-l shows the direct costs,  indirect costs including
 one year of contingency  and escalation,  and total capital costs
 for plants containing one to nine  converters without a baghouse
 in the  fugitive  emission discharge system.  Table A-2 includes
 the system of Table A-l  with  addition of a baghouse and appro-
 priate  increase  in  the  fan pressure design.

 Operating Costs

      Operating costs include operating labor at $8 per man-hour,
 supervision at 15  percent  of labor,   maintenance  for  labor and
 supplies at 2  percent of total capital  costs, maintenance mate-
 rials at 15 percent of maintenance  labor and supplies, electric-
 ity at  35 mills per kWh, plant overhead at  50 percent of opera-
 tions,  and payroll at 20 percent  of  the operating labor costs.
 The fixed  costs  include a  straight-line depreciation  over 15
 years,  0.3  percent for  insurance, 4  percent for taxes,  and 9
 percent for capital costs.   Table A-3 lists  the operating costs
 for a multiconverter plant without a baghouse in  the  fugitive
 emission discharge system.   Table A-4  includes  the system of
 Table A-3 with addition of a baghouse and appropriate increases
 in  energy and  maintenance costs.

      Additional  handling of  slag  and blister ladles may cause
 delays  in  operation  of  the movable  and  swing-away  converter
 hoods.   It  is  estimated that  a  delay  of  5 to 15  seconds  may
 occur with each ladle movement, equivalent to a total delay of 3
 to  10  minutes  per day  or  a  0.23 to  0.7  percent  slowdown in
 production.  This  loss  is calculated  on  an  annual basis as part
 of  the  operating  cost  since it is negligible in comparison with
 other delays that are  encountered (e.g., delay because matte is
 unavailable,  because  the  anode  furnace  cannot  accept  more
blister  copper,   or because  of  maintenance  of  converters  or
 furnaces.

     Each  of these  systems is connected  to a main discharge duct
 and an  exhaust fan  that exhausts to an existing stack.


COSTS OF AIR CURTAIN CONTROLS

     Order-of-magnitude costs  (±  35 percent) of an  air curtain
for  control of  fugitive  emissions were developed  in  a  manner
somewhat similar to that for secondary hooding systems.
                               84

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TABLE A-l.   ESTIMATED CAPITAL COSTS OF SECONDARY  HOODING  AT
           MULTICONVERTER PLANT WITHOUT BAGHOUSE
                         (dollars)
No. of
converters
1
2
3
4
5
6
7
8
9
Direct
costs
760,000
1,216,000
1,532,000
1,771,000
2,211,000
3,219,000
3,601,000
3,880,000
4,402,000
Indirect
costs
532,000
785,000
963,000
1,255,000
1,463,000
2,122,000
2,383,000
2,545,000
2,850,000
Total
costs
1,292,000
2,001,000
2,495,000
3,026,000
3,674,000
5,341,000
5,984,000
6,425,000
7,252,000
                            85

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TABLE A-2.   ESTIMATED CAPITAL COSTS OF SECONDARY
  HOODING AT MULTICONVERTER PLANT WITH BAGHOUSE
                    (dollars)
No. of
converters
1
2
3
4
5
6
7
8
9
Direct
costs
1,122,000
1,616,000
2,127,000
2,587,000
3,103,000
4,850,000
5,523,000
6,093,000
6,877,000
Indirect
costs
736,000
1,007,000
1,298,000
1,714,000
1,966,000
2,936,000
3,466,000
3,792,000
4,244,000
Total
costs
1,858,000
2,623,000
3,425,000
4,301,000
5,069,000
7,786,000
8,989,000
9,885,000
11,121,000
                       86

-------
                        TABLE A-3.  ESTIMATED ANNUAL OPERATING COSTS OF SECONDARY HOODING
                                   AT A MULTICONVERTER  PLANT WITHOUT BAGHOUSE
                                                    (dollars)
No. of
converters
1
2
3
4
5
6
7
8
9
Labor and
supervision
10,000
21,000
31,000
41,000
51,000
62,000
72,000
82,000
93,000
Maintenance ,
labor, supplies,
and materials
30,000
46,000
57,000
70,000
85,000
124,000
138,000
148,000
167,000
Overhead
plant and
payroll
22,000
38,000
50,000
64,000
78,000
105,000
119,000
131,000
149,000
Utilities
1,000
3,000
4,000
5,000
6,000
8,000
9,000
10,000
11,000
Fixed
costs
258,000
400,000
498,000
604,000
734,000
1,077,000
1,195,000
1,283,000
1,448,000
Total
annual
costs
321,000
508,000
640,000
784,000
954,000
1,376,000
1,533,000
1,654,000
1,868,000
00

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                      TABLE A-4.   ESTIMATED ANNUAL OPERATING COSTS OF SECONDARY HOODING AT
                                      A MULTICONVERTER PLANT WITH BAGHOUSE
                                                    (dollars)
No. of
converters
1
2
3
4
5
6
7
8
9
Labor and
supervision
17,000
28,000
3:8,000
48,000
58,000
72,000
82,000
92,000
103,000
Maintenance,
labor, supplies,
and materials
43,000
60,000
79,000
99,000
117,000
179,000
207,000
227,000
256,000
Overhead
plant and
payroll
33,000
50,000
66,000
83,000
99,000
140,000
161,000
178,000
252,000
Utilities
80,000
122,000
226, QOO
343,000
404,000
523,000
878,000
1,039,000
1,209,000
Fixed
costs
371,000
524,000
684,000
859,000
1,012,000
1,555,000
1,795,000
1,974,000
2,221,000
Total
annual
costs
544,000
784,000
1,093,000
1,432,000
1,690,000
2,469,000
3,123,000
3,510,000
4,041,000
CO
00

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     The design  evaluated here differs  from  the Mitsubishi air
curtain system  in that the side panels  are  extended to contain
the  area of  the ladle awaiting blister  copper  or slag from the
converter.    Also,  partial  covering  is  placed  on  the approach
side (Figure 37).

     The air flow across the top is set at 1000 Nm3/min, but the
collection side  is designed with its own  suction fan to handle
up  to  2500  Nm3/min so  as  to create  a flow pattern  that will
capture the  fugitives  during  charging, teeming,  slagging,  and
similar operations.

     Tables  A-5  and  A-6 show the  total  installed capital and
annual operating costs.


RELATIVE COSTS AND ENERGY REQUIREMENTS

     Table  A-7  summarizes  the  costs   of alternative  control
systems relative  to the  systems now in widespread use.   Table
A-8 lists the estimated energy requirements.
                               89

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       TABLE A-5.   ESTIMATED CAPITAL INSTALLED COSTS OF
AIR CURTAIN TYPE HOODING WITH BAGHOUSES AT MULTICONVERTER PLANT
                           (dollars)
No. of
converters
I
2
3
4
5
6
7
8
9
Direct
costs
$ 372,200
736,900
987,800
1,365,500
1,621,200
2,111,300
2,688,700
3,242,000
3,591,200
Indirect
costs
$ 586,700
926,700
1,222,200
1,708,800
2,010,200
2,725,500
3,406,300
4,189,800
4,630,300
Total
costs
$1,082,000
1,878,000
2,495,000
3,470,000
4,099,000
5,460,000
6,880,000
8,389,000
9,280,000
    Includes 5% contingency and 7-1/2% escalation for  1 year.
                              90

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TABLE A-6.  ESTIMATED ANNUAL OPERATING COSTS OF AIR CURTAIN TYPE HOODING
                 WITH BAGHOUSES AT MULTICONVERTER PLANT
                                (dollars)
No. of
converters
1
2
3
4
5
6
7
8
9
Labor and
supervision
17,000
28,000
38,000
48,000
58,000
72,000
82,000
92,000
103,000
Maintenance,
labor, supplies,
and materials
25,000
43,000
57,000
80,000
94,000
126,000
158,000
193,000
213,000
Overhead
plant and
payrol 1
20,000
29,000
36,000
47,000
54,000
76,000
92,000
110,000
120,000
Utilities
59,000
67,000
80,000
145,000
168,000
225,000
240,000
297,000
349,000
Fixed
costs
220,000
382,000
506,000
704,000
832,000
1,109,000
1,398,000
1,704,000
1,886,000
Total
annual
costs
341,000
549,000
717,000
1,024,000
1,206,000
1,608,000
1,970,000
2,396,000
2,671,000

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                           TABLE  A-7.   RELATIVE  COST EVALUATION OF ALTERNATIVE  AND EXISTING  SYSTEMS
Alternative
system
Cascade



Staggered with
Induction
pumping

4-BOF


Crane
evacuation
Covered bottom-
pour laoles
Floor operated
charger
Flash smelter
tpboken
converter
Individual
furnace
enclosure

Building
evacuation

Compared with
Roaster
Xc



X















X



X


Dryer
X



X















X



X


teverb
X



X



X


X

X

X

X


X



X


EAFa
X



X



X


X

X

X




X



X


Flash
shelters
X



X



X


X

X

X




X



X


P-S
converter
X



X



X


X

X

X


X

X



X


Anode
Furnace
X



X






X

X

X




X



X


BIDS costs b
•ligher
X



X






X



X




X



X


Same


















X








Less








X


















Problem
areas
Maintenance
Equipment location
Proximity of furnaces
Operating techniques
Maintenance
Equipment location
Proximity of furnaces
Operating techniques
Maintenance
Enclosure design
Operating techniques
Maintenance

Maintenance

Maintenance
Operating techniques

Mai ntenance/operati ng
techniques
Mai ntenance/operati ng
techniques
Air movement or
changes
Maintenance
Air movement or
changes
Capital
installed costs "
Higher
X



X






X

X

X




X



X


Same



























Less








X









X








Annual i zed .
operating costs
Higher
X



X






X

X

X




X



X


Same








X









X








Less



























r • b
Emissions
Minimal
X



X










X




X






Less








X


X

X




X





X


Same



























INJ
        Electric arc furnace.
        X indicates relative cost of alternative system; annualized operating costs include fixed operating and maintenance.
      c X indicates conventional equipment with which alternative  is compared.

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                       TABLE A-8.   ESTIMATED  ENERGY  REQUIREMENTS  FOR  CONTROL  OF  FUGITIVE
                       (GASEOUS AND  PARTICULATE)  EMISSIONS  AT  INTAKES  AND  DISCHARGE  POINTS
Process equipment
Roaster
Dryer
Outokumpu furnace
Noranda furnace
Electric arc furnace
Reverberatory furnace
Peirce-Smith converter
Hoboken converter
Anode furnace
EOT crane
Energy requirement, kWh/h
Secondary hoods;
capture hoods
minimum /maximum
192/200
156/162
30/149
60/149
89/176
53/149
168/216
17/108
55/108
7/73
Individual,
enclosure '
27
38
90
50
110
90
11
17
11

Building .
evacuation '
271
38
411
172
444
355
365
305
365

vo
U)
            Energy  expended  per  unit;  gas  stream  discharged  after passing  through a  baghouse.
            Operating  only when  emissions  are  being  captured.
            Operating  continuously.
            Air  changes  estimated  at  12  per  hour.

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                            APPENDIX  B

            TRIP  REPORT:   MITSUBISHI  METAL CORPORATION,
                       .   ONAHAMA,  JAPAN
 27  July  1979

 TRIP  REPORT
DCN 79-201-010-05-X
 To:        Alfred  B.  Craig,  Jr.
           Project Officer,  lERL-Ci

 From:      Richard T. Coleman, Jr.
           Project Director, Radian Corporation

 Subject:   Site visit to the Mitsubishi Metal Corporation
           primary copper smelter in Onahama, Japan

 Trip date: 9 and 10 July, 1979

 Contacts:  Izumi Sukekawa, Group Manager, Technical Sales Dept.
           Shun-Ichi  Ajima,  Manager, Technical Sales Dept.
           Hiroshi  Kono, Manager of Operations, Onahama Smelting
             & Refining, Ltd.
           Yoshiyuku  Tsuji,  Metallurgist, Asst. Superintendent
             of R&D,  Onahama S&R

 Purpose:   Investigate copper converter fugitive emission
             controls
Summary:

     The  combination  of  secondary  hooding,  air  curtains,  and
building enclosure and evacuation used to control fugitive emis-
sions  at  the Onahama smelter is  approximately  80  to 90 percent
effective  based  on  visual observation.   Additional  building
evacuation would  certainly  enable a 90 percent capture level to
be  maintained.   The  present system  does  not  impede converter
operations.   Visibility  from  the  crane cab  is  not seriously
impaired by gases and particulate.  However, additional building
ventilation  could improve  visibility and  reduce  potential  ex-
posure in the crane cab.
                                94

-------
     Mitsubishi  personnel  did not  seem to  favor any  detailed
study  of  their facility by EPA.   Any study of  a  system similar
to Mitsubishi's  would  have  to be a demonstration conducted at a
U.S. primary copper smelter.  It is recommended that this system
be  investigated  in detail  by both EPA and NIOSH  as  a potential
solution to the  fugitive emissions problem and as an engineering
control for S02, particulate, and volatile metals (Pb, As,  etc.)
in primary copper smelters.

General:

     The initial meeting with Messrs. Sukekawa and Ajima on July
9 took place in Mitsubishi  Metal's  Tokyo  office.   We discussed
the purpose  of  our trip,  emphasizing our interest  in  fugitive
emission  controls.  We explained lERL-Ci's involvement in non-
ferrous metals research during the past four years and indicated
that  demonstration of effective controls  is  a  key R&D  need.

     Their reaction during  that  meeting  and the subsequent trip
to Onahama on July 10 was that they have demonstrated that their
control  technology works   effectively  and it  is  commercially
available.  They did not indicate any willingness or interest in
participating in an EPA-funded testing or demonstration project.

     Messrs.  Sukekawa  and  Ajima were very cooperative  and they
and Messrs. Kono and Tsuji at the Onahama smelter provided a lot
of information concerning both the converter controls and the MI
(Mitsubishi)  smelting  process.   This  information is discussed
below.

Converter Fugitive Emission  Controls:

     Emissions  from  the five  converters  in the Onahama smelter
are controlled in four ways.  These are:

     0    Primary hoods,

     0    Secondary hoods,

     0    Air curtains, and

     0    Converter aisle building exhaust ventilation.

     This  combination  of controls  was  observed  to  work effec-
tively and captured an estimated 80 to 90  percent of the fugi-
tive  gases leaving the converter.   Only the  building exhaust
ventilation appeared to be  slightly underdesigned.  An increase
in  the gas  volume evacuated  from  the building  would probably
assure a 90 percent control  efficiency.
                               95

-------
      The converter control  system is pictured schematically  in
 Figure B-l.   During  normal  blowing and standby,  approximately
 950  Nm3/min of process gas  are  drawn through  each  primary hood.
 The  primary hoods are not water cooled  but  still fit  tightly  on
 each converter without  severe  buckling.  A gap  of only two  to
 three inches  is  maintained between  the  primary  hood  and the
 converter furnace.  This enabled  almost complete capture of SO2
 to  be maintained  during  the blowing cycle.    Fugitive emissions
 during blowing were observed to  be minimal.

      During charging  and pouring,  the  primary hood draft  is
 reduced  by approximately 65 to  80 percent.   The gas  concentra-
 tion being fed  to the acid  plant is used  as a control on the
 primary  hood  damper.   The  draft on  the  primary  hood  is  suf-
 ficient  to allow  perhaps  30 to  50 percent  control of  fugitive
 emissions during  the  period when the converter was rolled out.
 This is  possible  only because  no  air  is  introduced into the
 tuyeres  during these  periods.   Control  of the remainder of the
 fugitives  during  charging   and  pouring  is  provided  by  the
 secondary hoods, air curtains, and building  exhaust ventilation.

      The  secondary hoods are sheet metal  panels on either side
 of  the converter  which  rise approximately  14 meters  (50 feet)
 from the  floor of the  converter  aisle.  At the  top of these
 panels, three  fans are fitted into the hood.   The fans create  an
 air  curtain across the  slot in  the  top of  the secondary hood.
 The   slot  is  large enough   to  allow the  crane  cables to   be
 maneuvered during  both charging and pouring.  On the  other side
 of the slot is a  duct which collects  the exhaust from the three
 air  curtain fans.  The exhaust duct for  the  secondary  hood is  at
 the  top  of the sheet metal  panels on  the side farthest  from the
 converter  aisle.  This  arrangement is  depicted  in Figure  B-2.

      The  secondary hoods operate at  all  times.   During normal
 blowing and  standby, when the primary hood  covers  the converter
 mouth, only 800  to 1200 Nm3/min  are  exhausted  from  the secondary
 hood.  When charging or  pouring  is  in  process,  the gas volume
 exhausted  is  increased to between 2200  and  2500 Nm3/min.  These
 volumes are sufficient to establish  a good air flow pattern into
 the  hood  exhaust duct  and air curtain.  Some  gases, however,  do
 spill  out of  the front of the hood and  rise into  the converter
 aisle.   This  occurs mainly   during  charging  and pouring.   The
 secondary  hood was  observed to  capture an  estimated 30  to  50
 percent of those gases not collected by the primary hood during
 charging  and  pouring,   and  nearly all  fugitives during normal
blowing and standby.

     The  design basis  for the  secondary hood  gas  treatment  is
 2000  ppm  S02  concentrations   range  between 400 and  500 ppm S02.
These  gases  are mixed with  the  reverberatory  furnace  gases and
 are scrubbed in an MgO absorption  process (see attached report).
                               96

-------
to
                                         CONVERTER     A  5000 Nm3/min~j TO BAGHOUSE
                                      AISLE  EXHAUST   B  3800 Nm3/minj THEN  STACK
                      CONVERTER
                'BUILDING ENCLOSURES^
                   (NOT TO SCALE)
                                                                 KEY

                                                                 A  NORMAL BLOWING
                                                                     AND STANDBY
                                                                 B  CHARGING AND
                                                                      POURING
                       ,AIR CURTAIN
             PRIMARY HOOD
                   14m
               (NOT TO SCALE)
                                                      AIR CURTAIN
                                          A  800 to 1200 Nm/min
                                                                                           Tn
                                                                                           T0
                                EXHAUST   B  2200 to 2500 Nm3/minj  THEN STACK

                                                0 Nm3/min    } TQ MgQ ABSORBER
                                                1200 NmJ/min
                                                       SECONDARY
                                                      HOOD  EXHAUST
                                                   SECONDARY
                                                     HOOD
                                             RADIANT
                                            PRECOOLING
                                             CHAMBER
                                  CONVECTION
                                  TUBES AREA
                                                    CHAIN CONVEYOR

                                                      14.9m
CONVERTER
       HOOD   (A   950 Nm3/min
      EXHAUST f B   200 TO 300

15.2m(pLANT)DJ    Nm3/m1n
                                     4.1m
                   Figure B-l.  Schematic of the Onahama converter emission control  system.

-------
                                           AIR CURTAIN
                                                SLOT  FOR
                                              CRANE CABLE
                                                              SECONDARY
                                                             HOOD EXHAUST
                                                           TO MgO SCRUBBER
                                                                AIR CURTAIN
                                                                  EXHAUST
                                                                TO BAGHOUSE
                                                       FEED  HOPPER
PRIMARY HOOD
   (OPEN)
TUYERE AIR
              Figure B-2.   Converter hooding arrangement.
                                  98

-------
     The air curtain  across  the  slot in the secondary hood cap-
tures  those hot  gases which  would normally  pass through  the
secondary hood slot.   Three  fans  create the stream of air which
passes above the  slot in  the secondary hood and enters the cap-
ture duct  on the opposite  side  of the  slot.   This "push/pull"
technique is almost 100 percent effective in collecting fugitive
which would normally  escape  through the slot.   Only those gases
which  spill  out  of the  front  of  the  hood remain uncaptured.

     The gases  collected  by the  air curtain range between  100
and 200 ppm  SO2 .   They are ducted to a baghouse for particulate
removal and then are discharged through a stack.

     The  converter aisle  building  exhaust completes the  con-
verter fugitive  emission  control systems.   The converter aisle
has been almost completely enclosed with sheet metal partitions.
The major  effort involved separating  the reverberatory furnace
building from the  converter  aisle.   Only the major access doors
at  either  end  and middle of  the converter aisle  remain- open.
The reverberatory  furnace building  is  relatively free of SO2 as
a result  of isolating it from the  converter aisle.  However,  a
significant quantity  of S02 remained uncollected  at  the top of
the converter aisle.

     During  normal  blowing  and  standby,  5000  Nm3/min  are  ex-
hausted from the  building.   This  volume of air is ducted to the
same baghouse  which handles the  air curtain exhaust.  However,
each time  an air curtain is activated,  the building  exhaust is
reduced by  1200 Nm3/min,  the quantity  used by  the air curtain.
This system is not quite adequate for complete building ventila-
tion.  A  significant  increase  in  the  converter  aisle  exhaust
would probably  be needed to  clear the  residual  S02  which col-
lects at  the top of  the  building.  The residual S02 is  not  a
major problem and does not impair visibility from the converter
aisle crane cabs.

     With  three converters  operating,  one  on  standby  and  one
under  repair,  approximately  10,500 Nm3/min are  exhausted from
the converter  building.  This results  in a building  air change
once every  5^  to 6 minutes.  This is sufficient to maintain the
converter aisle  work  areas  relatively free from any significant
S02 concentrations.

Mitsubishi (MI) Process:

     Mitsubishi personnel provided information on their continu-
ous smelting  process.  The  information provided confirmed that
reported   in  "Emerging   Technology  in   the   Primary  Copper
Industry."  The  MI process is located  at the Naoshima smelter.
We  were  not able  to  arrange a visit to Naoshima because a new
plant management  was  taking over responsibility for the smelter
the same week we made our visit.
                               99

-------
      The MI process  is  a three  furnace smelting system.  A  65
 percent copper matte is produced  in  the smelting furnace.  Coal
 is  mixed with  the  concentrate to provide more uniform heat for
 smelting,  reduce the flame temperature  required  in  the furnace,
 and increase  the slag fluidity.   Supplementary oil fired  burners
 are also needed to  heat  the  furnace.   These  are two  changes from
 the  original  intent  of  operating  an  autogeneous  smelting
 furnace.  They have been made  necessary  because water cooling  of
 the furnace  refractory was   added  to  reduce refractory wear.
 This  loss of  heat made supplemental fuel necessary.

      Slag and matte from the smelting furnace  flow by gravity  in
 a  launder  to  the  electric  slag  cleaning  furnace.   The copper
 content of the  slag is  maintained at 0.5  to  0.6 percent Cu  by
 maintaining a reducing atmosphere in  the slag cleaning furnace.
 The slag then  flows by gravity to  the  converter furnace.

     The converter  furnace produces anode copper  which flows  to
 a holding  furnace  prior to  anode casting.  Slag from the con-
 verter  furnace  is  granulated separate  from  the  slag cleaning
 furnace  slag.   The  converter  furnace slag  is  then  recycled  to
 the smelting  furnace.

     Mitsubishi  has licensed their process to  Gulf Western for a
 65,000 metric  ton per year smelter in  Timmins,   Ontario.   This  is
 a 30  percent  increase in capacity over  the  50,000 mt/yr  smelter
 at  Naoshima.   Both  smelters  will be  similar in that the  concen-
 trates  processed contain  very little arsenic  (<100 ppm).   The
 Timmins,  Ontario  smelter,  however,   will   process  concentrate
 containing  up to  6 percent  zinc and 5 percent  lead.   Conse-
 quently, the  particulate removal  equipment  will  be  much larger
 than at the Naoshima smelter.

     Mitsubishi  is  presently marketing the  MI   process.   The
major advantages  cited  are:   energy efficiency, low atmospheric
emissions,   and no  converter  aisle.   Eliminating the converter
aisle   lowers   the   required  smelter  capital  investment  and
eliminates the fugitive emissions from crane operations.
                               100

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing}
1. REPORT NO.
   EPA-600/2-80-079
                              2.
             3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE

 Control of Copper Smelter Fugitive Emissions
             5. REPORT DATE
              May  1980  issuing date
                                                            B. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
 Timothy W.  Devitt
             8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS

 PEDCo  Environmental, Inc.
 11499  Chester Road
 Cincinnati,  Ohio   45246
             10. PROGRAM ELEMENT NO.
                 1AB604
             11. CONTRACT/GRANT NO.

              Contract  No.  68-02-2535
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental  Research Laboratory
Office  of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio   45268
             13. TYPE OF REPORT AND PERIOD COVERED
                Task Final:  3/7fi  - 10/79	.
             14. SPONSORING AGENCY CODE
                 EPA/600/12
15. SUPPLEMENTARY NOTES
16. ABSTRACT
      This  report deals with  fugitive emissions  from copper smelting  and  with related
 emission control measures.   The  study involved  evaluation of the controls  now used
 in the  copper smelting industry  and development of  suggestions for alternative control
 devices  and practices.

      A  brief overview of copper  smelting processes  is  followed by a  more detailed
 analysis of the conventional  processes identifying  portions of the operating cycle
 that produce fugitive emissions.   Emphasis is placed on Fierce-Smith Converting,
 which is one of the major emission sources in copper smelting.  Some alternate
 processes  now in limited used in the U.  S. are  described including estimations of
 fugitive emissions from these conventional and  alternative copper smelting processes.

      A  specific report on the utilization of the Hoboken Converter is  being prepared
 at the  time of this report.   The USEPA should be contacted if a copy of  this report
 is desired.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                               b.IDENTIFIERS/OPEN ENDED TERMS
                           :.  COSATI Field/Group
 Air Pollution  Control
 Copper Smelting
Fugitive Emissions
Copper Smelting
Pierce-Smith Converting
Hoboken Converters
 8. DISTRIBUTION STATEMENT

  RELEASE TO  PUBLIC
19. SECURITY CLASS (This Report}

  Unclassi f i'pd
21. NO. OF PAGES
         113
                                               20. SECURITY CLASS (Thispage)
                                                                          22. PRICE
EPA Form 2220-1 (Rev. 4-77)   PREVIOUS EDITION is OBSOLETE
                                             101
                                                                         V-SWEV "NTS: :» CE •9SC-657-146/5681

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