United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/3-87-011
June 1987
Air
Cadmium Emissions
from Cadmium
Refining and Primary
Zinc/Zinc Oxide
Smelting — Phase I
Technical Report
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EPA-450/3-87-011
Cadmium Emissions from Cadmium Refining and
Primary Zinc/Zinc Oxide Smelting — Phase I
Technical Report
Emission Standards and Engineering Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
June 1987
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This report has been reviewed by the Emission Standards and Engineering Division of the Off ice of Air Quality Planning
and Standards, EPA, and approved for publication. Mention of trade names or commercial products is not intended to
constitute endorsement or recommendation for use. Copies of this report are available through the Library Services
Office (MD-35), U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; or, for a fee, from
the National Technical Information Services, 5285 Port Royal Road, Springfield, Virginia 22161.
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TABLE OF CONTENTS
Page
I. DEFINITION OF SOURCE CATEGORIES 1
A. Cadmium Refining 1
1. Plants in operation 1
2. Processes 2
3. Projections of industry growth 4
B. Primary Zinc/Zinc Oxide Smelting _ 4
1. Plants in operation 4
2. Processes 4
3. Projections of industry growth 12
II. EMISSIONS AND CONTROLS 12
A. Cadmium Refining 12
B. Primary Zinc/Zinc Oxide Smelting 15
III. PUBLIC HEALTH RISKS 17
A. Risk Assessment 17
1. Background 17
2. Approach 18
B. Cadmium Refining 22
C. Primary Zinc/Zinc Oxide Smelting 24
IV. POTENTIAL FOR IMPROVED CONTROL 24
Cadmium Refining 24
V. REFERENCES 30
i i i
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LIST OF FIGURES
Figure Page
1 Flow diagram for cadmium refining 3
2 Typical process flow diagram for an electrolytic
zinc smelter 5
3 Process flow diagram, St. Joe Resources Company,
Monaca, Pennsylvania 8
4 Process flow diagram for the American Zinc Oxide
Process, New Jersey Zinc Company,
Pal merton, Pennsyl vani a 11
LIST OF TABLES
Table Page
1 Inventory of Cadmium Emission Sources and Controls
for Cadmium Refining Plants 13
2 Inventory of Cadmium Emission Sources and Controls
for Primary Zinc/Zinc Oxide Smelters 14
3 Summary of Emissions and Risks for Cadmium Refining
Plants at Typical Operating Conditions 19
4 Summary of Emissions and Risks for AMAX and ASARCO at
Maximum Operating Conditions 20
5 Summary of High Risk Sources at Cadmium Refining
PI ants 21
6 Summary of Emissions and Risks for Primary Zinc/
Zinc Oxide Smelters 25
7 Summary of Options for Improved Control and Associated
Impacts at Typical Operating Conditions 26
8 Summary of Options for Improved Control and Associated
Impacts at Maximum Operating Conditions 27
iv
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TECHNICAL REPORT:
CADMIUM REFINING AND PRIMARY ZINC/ZINC OXIDE SMELTING
I. DEFINITION OF SOURCE CATEGORIES
A. Cadmium Refining
Cadmium is principally a byproduct of zinc production and to a
lesser extent of copper and lead production. It is a relatively rare
element and in metal form is used for plating and alloying, accounting for
about 34 percent of total demand in 1983. Cadmium compounds used in
pigments, plastics, and batteries account for most of the remainder.!
Because cadmium is recovered mainly as a byproduct of zinc ore
processing, many producers of zinc and zinc compounds produce primary
cadmium as an integral part of their operation. In some cases, residues
and flue dusts from zinc producers are used directly by cadmium
producers. Some cadmium also is recovered from flue dust generated by a
lead smelter. 1
This report describes the sources of cadmium emissions from cadmium
refining plants and primary zinc/zinc oxide smelters, documents the health
risks attributable to these emission sources, and discusses the potential
for improvements in existing levels of control.
1. Plants in operation. At present, there are four cadmium
refining facilities in the U.S.: AMAX Zinc Company (AMAX) in East
St. Louis, Illinois; ASARCO, Inc., Globe plant (ASARCO) in Denver,
Colorado; Jersey Miniere Zinc in Clarksville, Tennessee; and St. Joe
Resources Company, National Zinc Division (National Zinc) in Bartlesville,
Oklahoma. The ASARCO plant produces only cadmium products. The other
three cadmium refining facilities are colocated with primary zinc
smelters. One additional cadmium refining operation, the ASARCO facility
in Corpus Christi, Texas, was permanently closed in May 1985.
Crude cadmium oxide (CdO) is produced at the Asarco El Paso plant.
Refined CdO is produced at the Witco Chemical Corporation plastic stabilizer
manufacturing plant in Brooklyn, New York. Although the Asarco-El Paso
lead plant is currently shut down with indefinite plans for startup, the
feed material for crude CdO production (blast furnace baghouse dust)
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is supplied by Asarco's East Helena lead smelter. Cadmium emission data
and risk values for Witco Chemical and Asarco-El Paso are included in the
technical reports for pigments and stabalizer manufacturing (ESED 80/42 c)
and primary lead and copper (ESED 80/42b), respectively.
2. Processes. Cadmium minerals do not occur in concentrations and
quantities sufficient to justify mining them in their own right, but they
are present in most zinc ores and are concentrated during zinc ore
processing. Cadmium is a byproduct of the extraction and refining of zinc
metal from zinc sulfide ore concentrates. Figure 1 is a general flow
diagram for cadmium refining.
The first step in the refining of zinc metal is roasting the
concentrates in a fluid bed roaster. This step removes up to 97 percent
of the sulfur present in the concentrates and produces an impure zinc
oxide product known as calcine.2 Cadmium, in the form of CdO, is an
impurity and must be removed as a part of the leaching and purification
process.
All cadmium recovery processes comprise the dissolution or leaching
of the cadmium-bearing feed material followed by various purification and
cadmium displacement steps. Recovery processing can be performed by
electrolytic and electromotive methods. In the former, cadmium is
recovered by electrolyzing purified solutions where the cadmium is
deposited on cathodes. After the deposition, the cathodes are removed
from the cells and stripped, and the cadmium metal is melted and cast into
the required shapes.3 This method is used at Jersey Miniere Zinc. In the
electromotive method, metallic cadmium, called "sponge" because of its
appearance, is displaced from the purified solutions by zinc dust.3 The
sponge is then briquetted, melted, and cast into shapes for sale or
further processing. This method is used at the other three plants;
however, the feed material at ASARCO Globe plant is the impure CdO pro-
duced at the ASARCO El Paso plant from the lead smelter blast furnace
baghouse dust received from ASARCO - East Helena.
Cadmium metal is produced in a variety of shapes. Slabs, ingots,
and sticks are used in alloying, pigments, and in the production of CdO,
which is often the initial input material for many cadmium uses. Balls
and sheets are required for plating anodes.3
2
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ZINC ROASTER CALCINE OR
LEAD SMELTER BAGHOUSE OUST
WEAK
SULFURIC
AGIO
LEACH TANKS
PURIFICATION
STEPS
ZINC DUST -
CADMIUM
PRECIPITATION
CADMIUM
PURIFICATION
STEPS
\'
CADMIUM SPONGE
PRECIPITATION
SPONGE
PURIFICATION
STEPS
CADMIUM PLATING IN
ELECTROLYSIS CELLS
CADMIUM
MELTING FURNACES
CADMIUM
CASTING
AIR
RETORT
FURNACES
RETORT
FURNACES
CADMIUM
METAL PRODUCTS
CADMIUM
METAL POWDER
PACKAGING
CADMIUM OXIDE
3AGHOUSES «
CADMIUM METAL
POWDER PRODUCT
CADMIUM OXIDE
PACKAGING .
•DENOTES POTENTIAL CADMIUM EMISSION
SOURCE
CADMIUM OXIDE
POWDER PRODUCT
Figure 1. Flow diagram for cadmium refining.
11
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Two of the four cadmium refining plants produce only cadmium metal
products, while the other two, ASARCO and AMAX, also produce cadmium metal
powder and/or CdO powder. At these two plants, cadmium metal from the
melting furnace is oxidized in air, and the CdO product is captured in a
product collection baghouse and packaged for sale. In the production of
cadmium metal powder, the entire system is purged with carbon dioxide and
the neck of the furnace is sealed to prevent air from entering the
system. Cadmium vapor from the retort furnace is rapidly cooled in a
condenser to form cadmium metal powder.
3. Projections of industry growth. The forecast of U.S.
demand for cadmium from 1983 to 2000, based on 1983 demand of 3,414
megagrams (Mg), is between 3,265 and 7,260 Mg. The probable demand of
4,540 Mg corresponds to an average annual growth rate of 1.7 percent for
the period.* One of the four plants is operating at 100 percent of
capacity. The other three plants have the capacity to meet the expected
demand because they are currently operating at 18, 61, and 88 percent of
capacity. Therefore no new cadmium refining plants are expected.
B. Primary Zinc/Zinc Oxide Smelting
1. Plants in operation. At present, there are four primary
zinc smelters in operation in the U.S.: AMAX, Jersey Miniere Zinc, National
Zinc, and St. Joe Resources Company (St. Joe) in Monaca, Pennsylvania.
There is one primary zinc oxide smelter in operation, the New Jersey Zinc
Company in Palmerton, Pennsylvania. St. Joe also manufactures zinc oxide
by refining zinc metal produced at the plant.
2. Processes. Of the primary zinc smelters, three are electrolytic
smelters while one (St. Joe) is an electro thermic smelter. All four plants
process zinc sulfide ore concentrates that contain from 0.1 to 0.8 percent
cadmium by weight. The electrothermic smelter, due to the nature of the
production process, also processes zinc secondary materials such as zinc
skimmings, drosses, scrap metal, and oxides. The following two sections
briefly discuss the two production processes. A third section discusses
the production process at New Jersey Zinc.
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ZINC ORE
CONCENTRATE
AIR
PRECLEANED ROASTER
OFFGAS TO AC 10 PLANT
CIRCUIT
SULFUR1C ACID
ZINC METAL -*•
ZINC OUST
ZINC OUST
ELECTROLYTIC
CELL HOUSE
DENOTES POTENTIAL CADMIUM EMISSION SOURCE
COLO
PURIFICATION
REACTOR
PURIFICATION
REACTOR
HOT PURIFICA-
TION REACTOR
ZINC OUST
~ IRON CAKE
COPPER CAKE
CADMIUM CAKE
COBALT CAKE
Figure 2. Typical process flow diagram for an electrolytic
zinc smelter.iz
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a. Electrolytic zinc production. A process flow diagram
for a typical electrolytic zinc smelter is shown in Figure 2.
(1) Roasting. The first step in the production of
zinc metal from ore concentrates at both electrolytic and electrothermic
zinc smelters is the roasting operation. Zinc roasting consists of
heating the ore concentrates to 650° to 1000° C in an oxidizing environment.
The roast is carried out below the melting temperature of the charge and
has three primary functions: (a) elimination of sulfur as S02, (b) conversion
of zinc sulfide to impure zinc oxide, and (c) removal of volatile impurities
from the ore concentrate. The degree of sulfur elimination accomplished
in a zinc roaster varies from about 93 to 97 percent.2
The fluid bed roaster is the newest roasting system for zinc sulfide
concentrates and is currently the only type in use. The outlet gas stream
from a fluid bed zinc roaster typically has an S02 concentration of 10 to
13 percent, and up to 85 percent of the roaster product (calcine) is
carried out with the off-gas. Waste heat boilers, cyclones, and
electrostatic precipitators (ESP's) are used in series to capture the
entrained portion of the calcine.2 The cleaned gas is then ducted to a
sulfuric acid plant. At electrolytic zinc plants the collected materials
are typically combined with the remaining portion of the calcine and
stored prior to leaching and purification.2
(2) Leaching and purification. The roaster calcine
is first leached in a dilute sulfuric acid solution to dissolve the
impure zinc oxide. Manganese dioxide is 'generally added to the leach
tank to cause the precipitation of an iron cake that contains iron and
significant amounts of arsenic, antimony, and silicic acid. The leachate
is then sent to a series of cold and hot purification tanks where cadmium,
copper, and cobalt are removed from solution. The precipitation reactions
that occur are induced by the addition of zinc dust, which reduces Cd+2,
Cu+2, and Co"1"2 to their respective metallic forms.2 All three electrolytic
smelters recover the precipitated cadmium and sell it as cadmium metal or CdO.
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(3) Electrodeposition. The purified zinc sulfate
solution from the purification system is passed to the cell room where an
electric potential applied to the solution causes zinc metal to form on
the surface of aluminum cathodes. Hydrogen gas is also evolved causing
the formation of sulfuric acid, which is recycled to the leach tank.5
The zinc metal sheets are subsequently stripped from the cathodes and
stored prior to melting and casting.
(4) Melting and casting. The zinc metal sheets are
charged to an electric induction furnace and melted down. Ammonium
chloride typically is added to the zinc sheets as a flux. The molten
zinc is then pumped to a holding furnace where pneumatic jets direct the
molten zinc into molds. Any impurities that form on the top of the
freshly poured zinc are skimmed off. Water is sprayed on top of the
molds to aid in cooling. At some plants, the area in which this cooling
takes place is enclosed. The zinc slabs are subsequently removed from
the molds, stacked, and stored for sale.
b. Electrothermic zinc production. The process flow
diagram for the St. Joe electrothermic zinc smelter is shown in Figure 3.
(1) Roasting and sintering. The zinc sulfide ore
concentrates are dried in a rotary dryer prior to roasting. Emissions
from the dryer are controlled by a venturi scrubber. The dried ore
concentrates are then roasted in a fluid bed roaster. Emissions from the
roaster are controlled in series by a cyclone, waste heat boiler, electro-
static precipitator, and a wet scrubber. The cleaned gas is then ducted
to a double-adsorption sulfuric acid plant.6
Roaster calcine, sand, coke breeze, electrothermic furnace residue,
blue powder from the electrothermic furnaces' scrubbers, and return sinter
fines are mixed together and pelletized. The pelletized material is then
roasted in downdraft sinter machines at an operating temperature from
1200° to 1300° C. The sinter machine product is subsequently crushed and
screened. Sinter fines from screening are recycled to the sinter machines.
Emissions from the sinter machines and from the crushing and sizing
operation are controlled by separate baghouses.6
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CONCINIMIIS
PROCESS FLOU
•- GAS FLOM
• DENOTES POTENTIAL
CADMIUM EMISSION
UMAUSI 10 SOURCE
00
COMCINMAIf
A IKMAGC
EXHAUST TO
ATMOSPHERE
ZINC OXIDE
Figure 3. Process flow diagram, St. Joe Resources Company, Monaca, Pennsylvania.£
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(2) Electrotheritric furnace operations. The advantage
of the electrothermic process over the electrolytic process is that a
significant portion of the feed may be comprised of secondary material.
Sinter, coke, and secondary materials are heated and mixed in a rotary
preheater and then charged to an electrothermic furnace. Emissions from
the electrothermic furnace preheaters are controlled by a baghouse.
Electricity is passed through eight pairs of graphite electrodes located at
the top and bottom of the furnace to generate the heat required for
smelting. Furnace vapors, including zinc vapor, are drawn through a
water-cooled condenser and bubbled through a molten zinc bath. The gases
vented from the condenser are scrubbed with water from high-velocity
impingers. The clean gas, which contains about 80 percent carbon monoxide,
is recovered and used as fuel. Any uncondensed zinc is recovered by
settling the water slurry in ponds. This zinc, which is called blue
powder, is recycled to the roaster. Furnace residue is discharged on a
rotary table at the base of the furnace. It is then treated to recover
coke and unsmelted zinc and to segregate slag and ferrosilicon by-products.6
(3) Zinc casting. Molten zinc from the electrothermic
furnace condenser is passed to a holding furnace. The zinc may then be
cast into 25-kilogram (kg) slabs, 227-kg blocks, or 1,090-kg jumbo blocks.
The casting process is fully automated. Molten zinc from the holding
furnace is tapped into molds which travel on a conveyor. Dross that
forms on the surface of the molten zinc after tapping is skimmed off and
stored for later use as furnace feed material. As the conveyor proceeds,
water is poured on top of the molten zinc to aid in cooling the slabs.
The slabs then pass into a hooding and ventilation system where more
water is sprayed onto the slabs; the steam produced is drawn off to the
atmosphere. The cooled slabs of zinc are then mechanically removed from
the molds, stacked, and stored for shipment.6
(4) Zinc refining. Further refining of the zinc
metal is accomplished using two types of refining columns known as cadmium
columns and lead columns. Molten zinc from the electrothermic furnace is
transferred to the cadmium column in large ladles. The molten zinc is
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fed at a constant rate to the column and flows Inside carbide trays. The
column is operated at a temperature high enough to drive off metals,
including cadmium, with a lower boiling point than zinc. Vapor from the
column is condensed in a condenser. The resulting cadmium/zinc alloy
contains approximately 3 percent cadmium by weight. This alloy is recycled
to the electrothermic furnaces.6
The partially purified zinc collected at the bottom-of the cadmium
column is processed through another column known as the lead column.
Here, the zinc is further purified by driving off zinc vapor and leaving
behind higher boiling metals such as lead and iron. The zinc vapor is
either condensed to produce high purity zinc metal slabs or oxidized to
produce high purity zinc oxide. The zinc oxide powder is captured in
product collection baghouses. Off-gases from the refining columns are
vented to two other baghouses.6
c. Operations at the New Jersey Zinc Company. The
New Jersey Zinc plant in Palmerton, Pennsylvania, is currently the only
plant in the U.S. producing zinc oxide using the American process. In
the American process, zinc ore concentrates or steel furnace fume are
used as the zinc feed material. Another process known as the French
process uses high purity zinc metal as a raw material and is, therefore,
a secondary zinc process and not considered in this study. As mentioned
in the Federal Register, October 16, 1985, the risk estimate for the
secondary zinc category is considered to be negligible as sources have
excellent control equipment. Two other plants formerly produced zinc
oxide using the American process. The ASARCO plant in Columbus, Ohio,
was permanently closed in April 1986, and the ASARCO plant in Hillsboro,
Illinois, now produces zinc oxide using only the French process.
The process flow diagram for New Jersey Zinc is shown in Figure 4.
This plant can process a low-sulfur zinc ore known as Sterling crude ore
and steel furnace fume that have cadmium contents of about 0.004 and 0.01
to percent by weight, respectively J Because the Sterling mine has been
closed, steel fume is the feedstock currently used by New Jersey Zinc.
Ore and coal are fed to the Waelz kilns where metals are volatilized and
10
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WAELZ KILN PRODUCT
BAGHOUSE OFF6AS
WAELZ KILN FUGITIVE
BAGHOUSE OFFGAS
WAELZ
KILN
PRODUCT
BAGHOUSE
MAEU
FUGITIVES
BAGHOUSE
WAELZ
FUGITIVE
OUST
ORE
•
WAELZ OXIDE
WAELZ KILN
OFFGAS
WAELZ KILN
SINTER MACHINE
BAGHOUSE OFFGAS
FUME KILN
BAGHOUSE
OFFGAS
SINTER
MACHINE
BAGHOUSE
DUST
SINTER MACHINE
OFFGAS
SINTER MACHINE
WAELZ SINTER
HORIZONTAL GRATE
FURNACE
FUME
KILN
BAGHOUSE
FUME
FUME KILN
CALCINE
FURNACE PRODUCT
BAGHOUSE OFFGAS
FURNACE
OFFGAS
FURNACE
PRODUCT
BAGHOUSE
TO FUME
TREATMENT
PRODUCT IINC
OXIDE
WAELZ RESIDUE
FURNACE RESIDUE
•DENOTES POTENTIAL CADMIUM EMISSION
SOURCE
Figure 4. Process flow diagram for the American Zinc Oxide Process,
New Jersey Zinc Company, Palmerton, Pennsylvania.13
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oxidized.8 The Waelz oxide product is cooled and collected in a baghouse
collector.9 The oxide is then sintered in a downdraft sinter machine to
reduce impurities such as lead and chloride. The last step in the process
is the final oxidation and purification. The sinter is mixed with coal
and fed to a moving-grate furnace. The oxide is volatilized, reduced to
metallic zinc, and then oxidized again. The purified zinc oxide is then
collected in a baghouse.9
3. Projections of industry growth. The forecast of U.S. demand
for zinc in the year 2000 is 1.4 million metric tons. The demand in 1983
was 930,000 metric tons. During the forecast period, U.S. dependence on
metal imports is expected to remain between 55 and 70 percent.10 No new
primary zinc smelters are expected to open because idle capacity is
available at the ASARCO Corpus Christi primary zinc smelter. The reopening
of this plant is unlikely and is dependent on an increase in both mine
production and the price of zinc.
II. EMISSIONS AND CONTROLS
A. Cadmium Refining
An inventory of cadmium emission sources at currently operating
cadmium refining plants showing estimated emissions and existing controls
is presented in Table 1. The cadmium emission estimates were generated
from Section 114 responses, emission test reports, trip reports, and the
previous cadmium source survey (Radian, 1985). Also, the methodologies
for determining these estimates were sent to each plant and the estimates
were revised based on industry comments. The two types of process emission
sources are cadmium melting furnaces and cadmium retort furnaces. These
process emission sources and their controls are discussed below.
Cadmium melting furnaces are used to melt either cadmium "sponge" or
sheets. A layer of caustic on the molten metal surface is used to prevent
oxidation, to help remove impurities, and to provide some control of
particulate matter at three cadmium refining plants. The other plant uses
a layer of resin.
12
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TABLE 1. INVENTORY OF CADMIUM EMISSION SOURCES AND CONTROLS FOR
CADMIUM REFINING PLANTS
Plant
AMAX Zi
East
111.
nc Company,
St. Louis,
Source
Cadmium melting furnace
Cadmium holding furnace
Cadmium casting furnace
Cadmium oxide furnace
Type3
H
H
F
H
Emissions,
Maximum
kg/yr
Normal
operation operation
70
93
-68
814
55
54
<1
496
Control
device13
UNC
UNC
UNC
BH
Jersey Mini ere Zinc,
Clarksville, Tenn.
Cadmium melting furnace
aH=point source; F=fugitive source.
t>UNC=uncontrolled; BH=baghouse; WS=wet scrubber; DS=dust suppressant.
CBased on AP-42 methodology which was developed for aggregate materials.
BH
National Zinc,
Bartlesville, Okla.
ASARCO Globe,
Denver, Colo.
Cadmium melting/casting
furnace
Cadmium tapping/casting
Dust charging
Premelt department
Casting/holding furnace
Purification sponge tank
Purification dept. stack
Solutions heating tanks
CdO baghouse No. 1
CdO baghouse No. 2
Cd metal powder packaging
Fugitives packaging dust
collector No. 1
Fugitives packaging dust
collector No. 2
Gypsum storage pilesC
(tailing piles)
H
H
H
H
H
H
H
H
H
H
H
H
H
H
<1
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TABLE 2. INVENTORY OF CADMIUM EMISSION SOURCES AND CONTROLS FOR
PRIMARY ZINC/ZINC OXIDE SMELTERS
Plant
AMAX Zinc Company,
East St. Louis, IL
Jersey Mini ere Zinc,
Clarksville, TN
Source
Raw material storage &
Zinc melting furnace
Zinc tapping/casting
Zinc dust process
Roadways0
Leach residue dryer
Raw material storage0
Calcine handling
Zinc melting furnace
Type3
unloading°F
H
F
H
F
H
H
H
H
Emissions,
kg/yr Control device0
54
<1
<1
<1
28 Road
17
100
1
4
- <1
Zinc metal powder process H <1
Zinc tapping/casting
Gypsum storage0
Roadways0
Screening tower
F
F
F
H
<1
<1
22
<1
UNC
BH
UNC
BH
sweeper/water spray
BH
BH
BH
BH
BH
UNC
UNC
Road sweeper
BH
National Zinc,
Bartlesville, OK
Raw material storage & unloading°F
Zinc tapping/casting F
Zinc metal powder process H
Zinc melting furnace H
Roadways0 F
Purified cooler H
Electrolyte cooler H
7 DS
d UNC
cl BH
a BH
4 Road sweeper/water spray
cl Demister
-1 Demister
•"12-
St. Joe Resources
Company, Monaca, PA
The New Jersey Zinc
Company, Palmerton,
PA
Raw material storage & unl
Zinc ore dryer
Zinc holding furnace
Zinc tapping/casting
Zinc metal powder process
Sinter machine
Sinter sizing/crushing
Zinc furnace preheaters
Refining column No. 1
Zinc oxide furnace
Roadways0
Refining column No. 2
Nuisance dust collector
Sterling ore storage0
Waelz kiln fugitives
Waelz kiln product
Sinter machine
Fume kiln
oading°F
H
H
F
H
H
H
H
H
H
F
H
H
F
H
H
H
H
2
1
<1
2
<1
1,430
147
262
<1
1
<1
<1
<1
1,840
<1
<1
1
110
102
Building and DS
WS
BH
UNC
BH
BH
BH
BH
BH
BH
Road sweeper
BH
BH
UNC
BH
BH
BH
BH
aH=pomt source; F=fugitive source.
bUNC=uncontrolled; BH=baghouse; WS=wet scrubber; DS=dust suppressant
cBased on AP-42 methodology which was developed for aggregate materials.
14
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Process cadmium emissions from the melting furnace are controlled by
a baghouse at Jersey Miniere Zinc and by a wet scrubber at National
Zinc. Jersey Miniere Zinc also has a hooding system that controls process
fugitive emissions from the charging/dressing port and from the tapping/
casting area. There is no such hooding system at the other three plants.
At AMAX, ventilation to the atmosphere for the cadmium melting furnace is
accomplished via natural draft. At ASARCO, forced ventilation is in
place during furnace operation and during charging and tapping/casting.
Cadmium emissions from all of these sources were estimated based on data
from stack tests performed at two of the plants.
Cadmium retort furnaces are used at AMAX and ASARCO. The processes
involved at these plants are similar in that cadmium metal is vaporized
and/or oxidized to produce cadmium metal powder or CdO. Cadmium oxide is
collected in product collection baghouses at both plants. Cadmium metal
powder is collected in a condenser at ASARCO. Cadmium emissions from the
retort sources at these two plants were estimated based on data from tests
performed on each stack.
B. Primary Zinc/Zinc Oxide Smelting
An inventory of cadmium emission sources at currently operating
primary zinc and zinc oxide smelters showing estimated emissions and
existing controls is presented in Table 2. The cadmium emission estimates
were generated from Section 114 responses, emission test reports, trip
reports, and the previous cadmium source survey (Radian, 1985). Also the
methodologies for determining these estimates were sent to each plant and
the estimates were revised based on industry comments.
Ore concentrate storage and handling and roasting operations at
electrolytic and electrothermic primary zinc smelters are similar.
Emissions from ore concentrate storage and handling are controlled by a
storage building equipped with three baghouses at Jersey Miniere Zinc
(typically only one baghouse operates). At two of the other three plants,
ore concentrates are enclosed to varying degrees in storage buildings. At
National Zinc, a latex dust suppressant is sprayed on the outside storage
piles once a year.
15
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Emissions from the roasters at all of the primary zinc smelters are
controlled by a variety of gas cleaning equipment including cyclones,
ESP's, waste heat boilers, wet scrubbers, and mist eliminators; after
leaving the gas cleaning equipment, roaster emissions enter a sulfuric
acid plant. Emissions of cadmium from the roasters at each plant are
assumed to be insignificant due to the extensive gas cleaning system and
the fact that any particulate matter entering the acid plant would be
caught in one of the four catalyst beds.
The leaching and purification operations associated with the
electrolytic process are wet operations and as such are not considered to
be sources of atmospheric cadmium emissions. At AMAX, however, the leach
residue material is dried and sold for further metals recovery. The leach
residue dryer is controlled by a baghouse. Other minor sources of cadmium
emissions at electrolytic plants are the zinc melting furnace, zinc
tapping/casting operations, and the zinc dust process. At each plant, the
zinc melting furnace and zinc dust processes are controlled by
baghouses. The zinc tapping/casting operations are uncontrolled and
ventilated to the atmosphere at Jersey Miniere Zinc and National Zinc.
This operation is uncontrolled and is not ventilated at AMAX. In general,
emissions of particulate matter, including cadmium, are well controlled at
electrolytic plants.
In the electrothermic process, cadmium is removed from the
zinc-bearing calcine mainly by volatilization of the material in sinter
machines. This is in contrast to the removal of cadmium by wet chemical
means in the electrolytic process. As a result, the potential for cadmium
emissions is greater in the electrothermic process than in the
electrolytic process. Separate baghouses are used to control emissions
from the following sources: sinter machines; sinter sizing/crushing,
sinter feed preparation, and the sinter machine feed bins and transfer
points; and the electrothermic furnace preheaters, furnace plant residue,
sinter residue, and coke sizing operations. The electrothermic furnaces
are each controlled by a condenser and scrubber system with the carbon
monoxide scrubber off-gases being used as fuel. The zinc furnace is
16
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controlled by a baghouse, while tapping/casting is uncontrolled and
ventilated to the atmosphere. The seven zinc refining columns (normally
a maximum of six operate at any one time) are controlled by two baghouses.
The zinc oxide produced by volatilizing the refined zinc from the refinery
columns is collected in one of three product collection baghouses.
Because the Sterling Mine, the source of zinc ore concentrates for
New Jersey Zinc, has been closed, the storage and handling of the
concentrate are unlikely to be sources of fugitive cadmium emissions. The
plant is currently using steel furnace fume with a cadmium content that
ranges from 0.01 to 0.4 percent by weight. This material is stored inside
a building and is, therefore, not considered to be a source of fugitive
cadmium emissions. Process fugitive emissions from the Waelz kilns are
collected by capture hoods and ducted to a baghouse. Process emissions
from the Waelz kilns are controlled by a baghouse. Process emissions from
the sintering operation are controlled by a baghouse. Process fugitive
emissions from the sintering operation and material handling also are
controlled by baghouses. Two other process sources, the fume kiln and
horizontal-grate furnace also are controlled by baghouses.
III. PUBLIC HEALTH RISKS
A. Risk Assessment
1. Background. Risk assessment is the process used by EPA to
develop quantitative estimates of public health risks associated with
individual and population exposure to a hazardous or toxic air pollutant.
The resultant estimates are considered by EPA to be rough but plausible
upperbound approximations of the risks. Two measures of risk are calcu-
lated. One is maximum individual risk (MIR) and the other is aggregate
risk. Maximum individual risk is an estimate of the probability of
contracting cancer experienced by the person or persons exposed to the
highest predicted annual average concentration of the pollutant. Aggregate
risk is an estimate of the increased number of cancer cases for the
entire population after 70 years of continuous exposure. It is expressed
in terms of annual incidence or number of cancer cases per year. Non-
carcinogenic health risks are not addressed in this study.
17
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The estimates are calculated by coupling a numerical constant that
defines the statistical exposure-risk relationship for a particular
hazardous pollutant with estimates of public exposure to the pollutant.
The numerical constant used by EPA in its analysis of carcinogens is
called a unit risk factor. It represents an estimate of the increase in
cancer risk occurring to a hypothetical individual exposed continuously
over a lifetime (70 years) to a concentration of 1 microgram per cubic
meter (ug/rtP) of the pollutant in the air the individual breathes. For
cadmium, the unit risk factor is estimated to be 1.8x10-3 or 1.8 chances
in 1,000.
Estimates of public exposure are derived using dispersion models and
census data contained in EPA's Human Exposure Model (HEM). Dispersion
models are used to predict concentrations of a pollutant in the ambient
air at varying distances in all directions within a 50 kilometer radius
from a stationary emission source. With inputs of emission estimates and
stack parameters such as height, gas velocity, gas temperature, and
diameter, the model is able to predict ambient pollutant concentrations
around the plant. By combining the predicted ambient concentrations with
population data, both the number of people exposed and their levels of
exposure can be estimated. More details on the methodology and assumptions
used in HEM are contained in User's Manual for the Human Exposure Model (HEM)
(EPA-450/5-86-001).
2. Approach. Emission estimates were generated for each of the
sources at all of the plants in both categories. The number of sources at
each plant varied from 5 to 13 sources for zinc/zinc oxide smelters and
from 1 to 12 sources for cadmium refining plants. Each source at each
plant was modeled separately, and individual values for MIR (expressed as
a probability for an individual) and aggregate risk (expressed as
statistical cases per year) were generated for each source. The risks
from all sources at a particular plant were then summed to provide MIR and
aggregate risk for that plant. Details of the methods used to develop the
health risk estimates for both source categories are described below.
18
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TABLE 3. SUMMARY OF EMISSIONS AND RISKS FOR CADMIUM REFINING PLANTS
AT TYPICAL OPERATING CONDITIONS
Plant
Cadmium
emissions,
kg/yr
Maximum
individual
risk
Annual
incidence,
case/yr
AMAX Zinc Co., East St. Louis, 111. 605 2.0x10-4 0.018
Jersey Mini ere Zinc, <1 1.0x10-7 <0.0001
Clarksville, Tenn.
National Zinc, Bartlesville, Okla. <1 4.9xlO-7 <0.0001
ASARCO, Denver, Colo. 1,220 1.4xlO~3 0.041
Total 1,830 1.4x10-3 0.059
19
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TABLE 4. SUMMARY OF EMISSIONS AND RISKS FOR AMAX AND ASARCO AT
MAXIMUM OPERATING CONDITIONS
Plant
Cadmium
emissions,
kg/yr
Maximum
Individual
risk
Annual
Incidence,
case/yr
AMAX Zinc Co., East St. Louis, 111. 1,040 4.6x10-4 0.034
ASARCO, Denver, Colo. 3.410 3.6xlQ-3 0.11
Total 4,450 3.6x10-3 Q.14
20
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TABLE 5. SUMMARY OF HIGH RISK SOURCES AT CADMIUM REFINING PUNTS
Plant
AMAX Zinc Co..
East St. Louis, 111.
ASARCO, Denver, Colo.
Source
CdO furnace
CdO furnace
Dust charging
Premelt department
Solution heating tanks
Dust collector No. 2
Dust charging
Premelt department
Casting furnace
Solution heating tanks
Dust collector No. 2
CdO baghouse No. 2
Dust collector No. 1
Operating
conditions
Normal
Maximum
Normal
Normal
Normal
Normal
Maximum
Maximum
Maximum
Maximum
Maximum
Maximum
Maximum
Cadmium
emissions,
kg/yr
496
814
72
707
203
175
194
1.580
792
421
196
99
86
Maximum
risk
l.lxlO'4
l.BxlO"4
1.5xlO'4
6.2xlO~4
3.1xlO'4
1.7xlO'4
4.0xlO'4
1.4X10"3
4.7xlO'4
6.4xlO'4
1.9xlO'4
2.3xlO~4
2.0xlO~4
Annual
Incidence
0.014
0.024
0.0026
0.023
0.0070
0.0058
0.0069
0.052
0.025
0.014
0.0064
0.0036
0.0031
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B. Cadmium Refining
The Inputs to the HEM, Including cadmium emission estimates and
stack parameters for cadmium refining plants, were generated from
Section 114 request responses, test reports, trip reports, and the
previous cadmium source survey (Radian, 1985). Also, the methodologies
for determining these estimates were sent to each plant and the estimates
were revised based on industry comments, as appropriate. -
The ASARCO cadmium refining plant at Corpus Christi, Texas is perma-
nently shut down. The ASARCO lead and copper smelting plant in El Paso,
Texas, and the Witco Chemical Corporation plastic stabilizer manufacturing
plant in Brooklyn, New York, both CdO producers, were included in the
health risk modeling performed for the Primary Lead and Copper Smelting
(ESED 80/42b) and Pigment and Stabilizer Manufacturing (ESED 80/42c)
projects, respectively. Therefore, only the four currently operating
cadmium refining plants were included in the health risk assessment.
Table 3 shows the emissions, MIR, and annual incidence for each plant
based on typical operating conditions. Two plants, AMAX and ASARCO, had
MIR's exceeding lxlO~4. The highest MIR (1.4x10-3) occurs at ASARCO, and the
annual incidence for this plant (0.041) is 69 percent of the entire category's
annual incidence. Both National Zinc and Jersey Miniere Zinc had total
plant MIR's far below the IxlO'4 level (4.9xlO-7 and 1.0xlO~7, respectively.)
For AMAX and ASARCO, the HEM was run a second time using a cadmium
emission estimate for each source at maximum operating conditions.
Maximum operation is considered unlikely due to the depressed state of the
cadmium refining industry. The Jersey Miniere Zinc and National Zinc
typical operating rates are 88 and 100 percent of capacity, respectively.
Because both plants' MIR's were very low, the HEM was not run again using
maximum operating conditions for these plants. Table 4 shows emissions,
MIR, and annual incidence for AMAX and ASARCO based on maximum operating
conditions. Again, ASARCO has the highest MIR (3.6xlO~3), and the annual
incidence for this plant (0.11) is 76 percent of the annual incidence for
the two plants.
22
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A summary of the individual sources that contribute the most to the
risk at each plant is presented in Table 5 for both typical and maximum
operating conditions. At typical operating conditions, the CdO product
collection baghouse at AMAX is responsible for more than 78 percent of the
annual incidence attributable to this plant. At maximum operating
conditions, this baghouse is responsible for more than 71 percent of the
annual incidence. Although the outlet particulate matter concentration is
low, 0.018 grains per dry standard cubic foot (gr/dscf), based on emission
test data, 30 - 69 percent of the particulate matter in cadmium.
At typical operating conditions, four sources at ASARCO are
responsible for 94 percent of the annual incidence attributable to this
plant: dust charging to the leaching process, the premelt department, the
solutions department heating tanks stack, and fugitive packaging dust
collector No. 2.
Impure CdO dust is charged to the leaching process. Emissions are
vented to the atmosphere uncontrolled. A test conducted by ASARCO shows
the outlet particulate emissions to be 0.004 gr/dscf.
A hooding system is in place to vent cadmium emissions from tapping
and casting operations to the atmosphere uncontrolled. All emissions are
vented through the same stack. A test conducted by ASARCO shows the
outlet particulate emissions from this stack to be 0.021 gr/dscf.
Emissions from the solution heating tanks are vented to the
atmosphere uncontrolled. A test conducted by ASARCO shows the outlet
particulate emissions to be 0.018 gr/dscf.
In the retort department, fugitive emissions from the packaging
operations are captured by fugitive dust collector No. 2. A test
conducted by ASARCO shows the outlet particulate emissions to be
0.0002 gr/dscf.
At maximum operating conditions, three other sources at ASARCO Globe
have MIR's greater than lxlO~4: the casting/holding furnace, CdO product
collection baghouse No. 2, and the fugitive packaging dust collector
No. 1.
23
-------
Cadmium metal bricks are melted and cast into either balls or
sticks. Emissions are vented to the atmosphere uncontrolled. Test data
for this source are unavailable, and emissions were estimated based on
emissions from the premelt department stack test.
Cadmium metal bricks are oxidized in air, and the CdO product is
captured in a product collection baghouse. A test conducted on the No. 2
baghouse by ASARCO shows the outlet particulate emissions to be
0.003 gr/dscf.
Fugitive dust collector No. 1 performs the same function as fugitive
dust collector No. 2 in the retort department. A test conducted by ASARCO
shows outlet particulate emissions to be 0.001 gr/dscf.
C. Primary Zinc/Zinc Oxide Smelting
The HEM inputs for zinc/zinc oxide smelters were generated from
Section 114 responses, trip reports, and the previous cadmium source
surveys (Radian, 1985; GCA, 1981). Also, the methodologies for
determining these estimates were sent to each plant, and the estimates
were revised based on industry comments, as appropriate. Only those
currently operating primary zinc/zinc oxide smelters were included in the
analysis. Table 6 shows the emissions, MIR, and annual incidence for each
plant based on current operating conditions. Because all of the primary
zinc/zinc oxide smelters are currently operating at or near 100 percent of
capacity, the maximum MIR's and annual incidences are reflected in
Table 6. None of the primary zinc/zinc oxide smelters have MIR's greater
than IxlO-4.
IV. POTENTIAL FOR IMPROVED CONTROL
Cadmium Refining
The results of the risk analysis indicated that two plants, AMAX and
ASARCO, had MIR's from cadmium exposure in excess of 1x10-4 and annual
incidences in excess of 0.01 case. Therefore, each point source of cadmium
at each of these two plants was evaluated to determine the potential for
improvements in existing control. If the existing particulate matter
emissions were less than or equal to 0.005 gr/dscf (the lowest particulate
matter standard that would likely be technically enforceable for these
24
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TABLE 6. SUMMARY OF EMISSIONS AND RISKS FOR PRIMARY
ZINC/ZINC OXIDE SMELTERS
Plant
Cadmiurn
emissions,
kg/yr
Maximum
individual
risk
Annual
incidence,
case/yr
AMAX Zinc Co., East St. Louis, 111. 100 8.3x10-5 0.0029
Jersey Miniere Zinc, 28 5.0x10-5 0.0002
Clarksville, Tenn.
National Zinc, Bartlesville, Okla. 12 1.8x10-5 <0.0001
St. Joe, Monaca, Pa. 1,840 5.6xlO~6 0.0076
New Jersey Zinc, Palmerton, Pa. 215 2.6xlO~5 0.0011
Total 2,200 8.3x10-5 o.Oll
25
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TABLE 7. SUMMARY OF OPTIONS FOR IMPROVED
AT TYPICAL OPERATING CONDITIONS
CONTROL AND ASSOCIATED IMPACTS
(April 1986 Dollars)
ro
CT>
Plant/source
AMAX Zinc Co.,
East St. Louis, IL
1. Cadmium melting
furnace
2. Cadmium holding
furnace
3. Cadmium casting
furnace
4. Lead anode
furnaces (2)e
5. CdO furnace
ASARCO, Inc.,
Denver, CO
6. Dust charging
7. Premelt department
8. Casting furnace
9. Solution heating
tanks
Existing
control
UNCC
UNC
UNC
BH<1
BH
UNC
UNC
UNC
UNC
Improved control
One baghouse for control
of sources 1,2, and 3;
99.5% efficiency
One baghouse for control
of sources 1 through 4;
99.5% efficiency
Increased pressure drop to
improve baghouse efficiency
to 99.98%
Baghouse for control of
sources 7, 8, and 9; 99.5%
efficiency
Wet scrubber (pressure drop=
12 in. w.c.)
Emission
reduction,
kg/yr
109
109
356
778
162
Incidence
reduction,
case/yr
0.0034
0.0034
0.008
0.011
0.0256
0.0058
0.031
Capital
cost, $
350,000
580,000
0
MIR: 2
670,000
89,000
MIR: 1
Annual i zed
cost, $a D
77,600
120,000
4,550
.OxlO-4 to 6.
174,000
30 000
.4xlO-3 to 3.
$/life
savedb
22,800,000
35,200,000
569,000
5x10-5
6,810,000
5,170,000
4x10-4
^Includes a particulate recovery credit of $3,300/Mg.
^Values presented here have been rounded. Exact values were used in the calculation of $/life.
cUNC=Uncontrolled.
dBH=Baghouse.
eNot a cadmium source.
-------
TABLE 8. SUMMARY OF OPTIONS FOR IMPROVED 'CONTROL AND ASSOCIATED IMPACTS
AT MAXIMUM OPERATING CONDITIONS (April 1986 Dollars)
ro
Plant/source
AMAX Zinc Co.,
East St. Louis, IL
1. Cadmium melting
furnace
2. Cadmium holding
furnace
3. Cadmium casting
furnace
4. Lead anode
furnaces (2)e
5. CdO furnace
ASARCO, Inc.,
Denver, CO
6. Dust charging
7. Premelt department
8. Casting furnace
9. Solution heating
tanks
Existing
control
UNCC
UNC
UNC
BHd
BH
UNC
UNC
UNC
UNC
Improved control
One baghouse for control
of sources 1,2, and 3;
99.5% efficiency
One baghouse for control
of sources 1 through 4;
99.5* efficiency
Increase pressure drop to
Improve baghouse efficiency
to 99.98%
Baghouse for control of
sources 7, 8, and 9; 99.5%
efficiency
Wet scrubber (pressure drop=
12 in. w.c.)
Emission
reduction,
kg/yr
230
230
584
2,560
337
Incidence
reduction,
case/yr
0.0072
0.0072
0.017
0.024
0.084
0.012
0.096
Capital
cost, $
350,000
580,000
0
MIR:
670,000
89,000
MIR:
Annual 1 zed
cost, $a °
119,000
177,000
7,490
4.6x10-4 to 8
192,000
46,400
3.6x10-3 to 7
I/life
savedb
16,600,000
24,600,000
441,000
.5x10-5
2,290,000
4,000,000
.4x10-4
aincludes a particulate recovery
bValues presented here have been
qjNC=Uncontrolled.
dBH=Baghouse.
eNot a cadmium source.
credit of $3,300/Mg.
rounded. Exact values were used in the calculation of $/life.
-------
source categories), no further evaluation of improved control was performed.
If the particulate matter emissions were greater than 0.005 gr/dscf, control
options were developed and control costs were calculated. Fugitive emission
sources, regardless of emission rate, were also evaluated to determine the
potential for improved control.
For AMAX, the following control sources were identified for improved control:
the holding, melting, and casting furnaces (all currently.uncontrol1ed), and the
CdO baghouse. Tables 7 and 8 show the possible control improvements for these
sources together with associated costs and cost effectiveness (including a par-
ticulate recovery credit of $3,300/Mg) for typical and maximum operating con-
ditions, respectively. Improved control options evaluated included applying
baghouse control to the three cadmium furnaces that are currently uncontrolled
and operating the existing CdO baghouse at a higher pressure drop. An emission
test was conducted by AMAX on the existing CdO baghouse after this document was
sent for review. Particulate emissions for this test were less than 0.005 gr/dscf.
The bag life prior to this test was much shorter than the bag life prior to EPA's
test. Thus, increased maintenance, as well as increased pressure drop, can also
reduce emissions to 0.005 gr/dscf. The combined effect of improved control
reduces the total plant MIR from 2.6xlO~4 to 6.5xlO~5 for typical operating
conditions and from 4.6xlO~4 to 8.5xlO~5 for maximum operating conditions.
For ASARCO, the following sources were identified for improved control: the
dust charging to leaching operation, the premelt department, the casting
furnace, and the solutions department heating tanks. Tables 7 and 8 show the
possible control improvements for these sources together with associated
costs and cost effectiveness for both typical and maximum operating conditions.
Improved control options evaluated included installation of a baghouse for
control of the dust charging operation, premelt department, and casting
furnace that are currently uncontrolled, and installing a wet scrubber on the
uncontrolled solution heating tanks. The combined effect of improved control
reduces the total plant MIR from 1.4x10-3 to 3.0xlO~4 for typical operating
conditions and from 3.6xlO"3 to 7.2xlO~4 for maximum operating conditions.
Implementing these improved controls will not reduce the MIR below 1x10-4;
however, each source at the plant would be controlled to a level less than or
equal to 0.005 gr/dscf.
28
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The information concerning operating hours and emissions for ASARCO's
Globe plant as discussed above, is based on information submitted to EPA and
the State of Colorado by ASARCO. Estimates of operating hours and emission
rates for the maximum operating conditions are based on information supplied
by ASARCO to the State of Colorado. Draft estimates and calculations prepared
by EPA for typical operating hours were submitted to ASARCO for review.
ASARCO's initial comments on these estimates and calculations were incorporated
into a draft report.
The draft report and the subsequent dispersion analysis were then reviewed
by ASARCO and they provided additional comments on the operating hours for
the typical maximum operating conditions. Resolution of the differences
between ASARCO's comments on the draft report and the dispersion analysis
versus their original submittals and comments has not been possible. Since
this plant has been assigned for further study under the State Initiative
Program, the State of Colorado will further investigate the process, operating
hours and emissions.
29
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V. REFERENCES
1. Plunkert, P. A. Cadmium, A Chapter From Mineral Facts and Problems,
1985 ed. U.S. Bureau of Mines, p 1.
2. Background Information Document for Cadmium Emission Sources. Final
Report. Radian Corporation. Prepared for U. S. Environmental
Protection Agency, Research Triangle Park, N.C. May 1985. p. 43.
3. Reference 1, p. 3.
4. Reference 1, p. 7.
5. Reference 2, p. 44.
6. M. Turner, MRI, to W. Neuffer, EPA:ISB. August 6, 1986. Trip
report for St. Joe Resources Company, Monaca, Pennsylvania. 9 pp.
7. Response to Section 114 information request. The New Jersey Zinc
Company. May 16, 1986. pp. 5-6.
8. Reference 2, p. 61.
9. Reference 2, p. 63.
10. Jolly, J. H. Zinc, A Chapter From Mineral Facts and Problems, 1985
ed. U.S. Bureau of Mines, p. 15.
11. Reference 2, p. 10.
12. Reference 2, p. 42.
13. Reference 2, p. 62.
30
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-450/3-87-011
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Cadmium Emissions from Cadmium Refining and Primary
Zinc/Zinc Oxide Smelting - Phase I Technical Report
5. REPORT DATE
May 1987
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-3817
12. SPONSORING AGENCY NAME AND ADDRESS
DAA for Air Quality Planning and Standards
Office of Air and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A technical report on cadmium emissions from cadmium refining and primary zinc/zinc
oxide smelting. Descriptions of these industries and associated air pollution control
equipment are presented. Cadmium emissions from all plants in the U.S. in these two
source categories are presented. Health risks from exposure to cadmium air emissions
from each plant is also discussed.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Air Pollution
Pollution Control
Hazardous Air Pollutants
Cadmium emissions
Cadmium refining
Zinc/Zinc Oxide Smelting
Air Pollution Control
13B
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
34
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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