-------
oo
LU
^>
1— !
I—
^^
OL
LU
1—
_J
•sf
_J
O
1—
-"••i* 2H
-P 0
0
§ CM
0 0
Zz, oo
o
O\ ' ' '
CM 1—
1 <->
If) LU
L ,J
LU
CD OO
r~
.a o:
ffl ^D
1- LL.
OO
1—
00
o
CD
HH
1—
LU
CL.
O
O)
C
•i- C
C 0
• •
c
o
«^-
•p
(O
S-
4^
C
OI
o
c
o
o
CM
O
OO
4^
(U
•^
1— 1
O)
o
0)
s_
d)
O)
o;
o
•p
(O
o:
•P
•r-
C
13
S-
O)
4->
cu
E
ft)
s-
(O
Q.
Ol
•r-
4->
s-
0)
o
oo ro co co r^% oo
r^—
ro
i— -P r—
("0 ^5 (O
>> -p h- -p
rB " — O >
i -P T3
•r- ro
cocioiac c >, «a:'r-4->QQO(O
i--p-r-a>3coES-(tJ i — »* -PV) CO-P
OCi — O •OrtfCO.Ci — (O OCOt3'OS-T-
r^ .^ O O S C OJ S 4** CO 1 ^ ^C OO TD 3 £ *r- 't— f^ r^
fO fO O Sta (O O 4-* O CO 3 *O j. CM O *O "f™ O O CO fO
i y* CJ CX. r^ (_j oO ^ ?g" 1 1 t > /*^ T* t/) <_5 j ^f ^f /^ e ^
6-129
-------
Several factors should be kept in mind when analyzing the results
presented in Table 6-27. The first is that the control costs have
been calculated on the basis that the smelter is a grass-roots lead
smelter. The cost to install and operate comparable control equipment
in a modified existing smelter would be greater than in a grass-roots
lead smelter. It is conceivable that the installed capital costs for
the same control equipment could be as much as twice as much in a
modified smelter as they would be in a grass-roots smelter. Operating
costs would not increase as much, but depreciation and other capital-
related charges would increase proportionally with the increased capital
requirements.
Another fact to consider is that the control costs shown in Table
6-27 will vary with both the amount of sulfur in the concentrate
and the capacity of the smelter. Cases I and II shown in Table '6-27
are based upon a model smelter producing 100,000 tons per year of lead
metal from a concentrate containing 55% lead and 16% sulfur, and Case III
is based on a smelter producing 100,000 tons per year of lead metal
from a concentrate containing 65% lead and 16% sulfur. The 100,000 ton-
per-year capacity is typical of most existing domestic lead .smelters
and is in agreement with the recent: industry construction. The
concentrate analyses are assuned to be representative of the
concentrate processed at a new source lead smelter utiliz-
ing these production techniques. However, it is possible that variations
in this analysis could occur and a smelter that processes ores higher in
sulfur content relative to the ores processed by the model smelter will
have control costs greater than what is shown for the model smelter. For
example, a 100,000 ton-per-year smelter that utilizes a recirculating
sintering machine to process concentrates containing 55% lead and 16%
sulfur and uses a single-stage acid plant without neutralization for
control of the sintering machine strong stream will incur capital costs
of approximately $4.9MM and annualized costs of 0.664/lb of lead (refer
to Table 6-27, Case I la). If the sulfur content of the concentrate
were to increase to 20% and lead analysis remained unchanged at 55%,
the capital costs would increase from $4.9MM to $5.6MM and the annualized
control costs would increase from 0.66<£/lb to 0.75^/lb of lead. Of course,
comparable sabings would be realized if the sulfur content were to
6-130
-------
decrease relative to the lead analysis. It is expected that.on the
average, the variations in sulfur content will approximate the model
smelter analysis, but the possibility does remain that a new source
lead smelter could have greater (or less) control costs than are
shown in the attached Tables.
Another factor to keep in mind when examining these tables is
the assumptions regarding the treatment or sale of the by-products
produced by the various pollution control alternatives. In Table 6-27
there are shown two basic alternatives dealing with disposition of the
sulfuric acid that is produced by either a single-stage or a dual-stage
acid plant. The first alternative is that of selling the acid at zero
netback to the production plant. This alternative assumes that the
price paid to the producer for the acid is equal to the producer's cost
of shipping the acid to the purchaser. The second basic alternative
dealing with disposition of the acid is that of neutralization. In this
alternative the acid is first neutralized and then disposed of in lined
ponds so that no water pollution problems are presented. With this
alternative the control cost is equal to the production cost of the acid
plus the cost of neutralization and disposal. With regard to the produc-
tion of sulfur, the only alternative presented is that of sale of the
sulfur at zero netback. In this case the cost of control is equal to
the production cost of the sulfur. To fully illustrate this factor of
by-product disposal, Table 6-30 summarizes the impact of various
disposal options for a new source smelter that utilizes a recirculating
sintering machine for sulfur elimination. Control of emissions is
accomplished by either a dual-stage acid plant or an elemental sulfur
plant. The result for other smelter processes and control systems would
be comparable.
As can be seen,the method of disposition of the by-products makes
a considerable difference in the final control cost. The smelter
operator who is able to sell his acid, even at zero netback or a slight
loss, is in a better position that the producer who has to neutralize
his acid. It would require a sales price of approximately $15/ton for
the acid in order to fully recover pollution control costs in this
particular case of a dual-stage acid plant controlling the sintering
machine strong sulfur dioxide stream.
6-131
-------
Table 6-30 Impact of Disposal Options
1. Produce acid and sell at
$5/ton net to plant
2. Produce acid and sell at
zero netback to plant
3. Produce acid and neutralize
4. Produce acid and sell at
loss of $5/ton net to plant
5. Produce sulfur and sell at
$15/ton net to plant
6. Produce sulfur and sell at
zero netback
7. Produce sulfur and sell at
net loss of $15/ton net to
plant
Capital
Requirement
($MM)
5.01
5.0
7.2
5.0
13.2
13.2
13.2
Annualized
Control Cost
U/lb of lead)
0.54
0.72
1.03
0.90
1.70
1.88
2.06
6-132
-------
A smelter operator probably would not produce sulfur anless he was able
to receive a very high price for his sulfur production. It would
require a sulfur price of approximately $85/ton in order to be equivalent
to the annual control costs of 1.03^/1b of lead resulting from the option
of neutralizing the total sulfuric acid production. Not only is sulfur
manufacture more costly than acid neutralization, but the capital requirement
is $6.0MM more than the capital required for acid production and
neutralization.
A brief discussion of each control alternative summarized in
Table 6-27 and represented schematically in Figures 6-12 through
6-14 follows:
Case I(a)
This model is typical of present smelter processing procedures
and control techniques. The sintering machine is operated with a dual-
stream configuration with a strong stream of 6.5% processed in a
conventional single-stage acid plant; a weak stream of 0.5% S02 is
ducted to a baghouse for particulate collection. The off-gas flowrate
from the machine is 81,000 SCFM in the weak stream and 19,000 SCFM in
the strong stream. Thus, the acid plant was sized to process a gas
stream of 19,000 SCFM and 6.5% S02> producing 230 TPD of 100% H2S04-
Case I(b)
This model is essentially the same as Case I(a) with the exception
of the incorporation of a dual-stage acid plant rather than a single-
stage acid plant, resulting in the production of 236 TPD of 100% H2SO..
Case I(c)
Essentially the same as case I(b); however, weak-stream off-gases
from the sintering machine are processed in DMA unit to produce 100%
S02 which is combined with the off-gases of the strong stream. The
dual-stage acid plant is thus sized to process a gas of 19,100 SCFM
flowrate and 8.5% S02. The resulting acid production is 314 TPD of
100% H2S04.
Case I(d)
In addition to controlling weak gases from the sintering machine,
the weak gas from the blast furnace is ducted to the DMA unit. The
resulting gas stream to the DMA unit is 110,000 SCFM flowrate and 5%
6-133
-------
SOp- The S02 collected in the DMA unit is ducted to a dual-stage acid
plant resulting in a production rate of 343 TPD of 100 percent H2S04.
Case Ufa)
All off-gas from the sfntering machine is ducted in a single
stream to a single-stage acid plant. The off-gas flowrate is 33,000
SCFM at 5%' S02. Thus the acid plant is sized to process a 33,000
SCFM gas flow resulting in a capacity of 306 TPD of 100 percent H2S04.
Case II(b)
This model is essentially the same as Case II(a) with the
exception of the incorporation of a dual-stage acid plant rather than
a single-stage acid plant, resulting in the production of 315 TPD of
100 percent H2S04.
Case II(c)
The weak off-gas 0.5% S02 from the blast furnace is scrubbed and
concentrated in a DMA unit. The 100% S02 stream from the DMA unit is
combined with the sinter machine gases and processed in a dual-stage
acid plant resulting in the sizing of the acid plant to accommodate a
gas stream of 34,000 SCFM and 5.percent S0«. The resulting
production is 347 TPD of 100 percent H2S04.
Case II(d)
Off-gases from the sintering machine are ducted to a DMA unit
where the S0? is scrubbed from the gas stream, concentrated and ducted
to an elemental sulfur plant. Thus, the DMA unit is sized to
accommodate a gas stream of 37,000 SCFM flowrate at 5% SO,,. The
sulfur plant is sized to accommodate a S02 stream of 1800 SCFM S02
thereby producing 104 TPD of elemental sulfur. Sulfur oxide emissions
from the sulfur plant are ducted back to the DMA unit.
Case III(a)
Off-gases from the electric furnace are ducted to a single-stage
acid plant. In addition,during its blowing period the lead converter
gases are combined with the electric furnace gases to produce a gas
stream of 31,000 SCFM and 7% SQ^. Thus the acid plant is sized to
process a gas stream with the above characteristics producing 219
TPD of 100 percent HS0-
6-134
-------
Case III(b)
Essentially the same as case III(a) with the exception of the
incorporation of a dual -stage plant rather than a single-stage
acid plant, resulting in the production of 225 TPD of 100 percent
Case III(c)
Off-gases from the electric furnace and the converter with a
maximum flowrate of 33,000 SCFM are ducted to a DMA unit. The off-
gases are scrubbed and a maximum SCFM of 100% SOo is ducted to
* <-
an elemental sulfur plant. Thus the DMA unit is sized to process a
33,000 SCFM gas flowrate and the elemental sulfur plant is sized to
k process a maximum flowrate of 2500 SCFM of 100% 503; 70 TPD of
elemental sulfur is produced.
6-135
-------
6.3.3 Impact of New Source Performance Standards
The prospect of future growth in the domestic primary lead industry by
the addition of new smelting capacity appears remote. The industry as a whole
is producing at less than capacity rates, and future growth in consumption
appears slight. Due to these two factors any large additions to industry capa-
city seem improbable in the near future. A possibility does exist that
expansions could occur at existing plants,thereby increasing industry capacity,
but major growth via this route is unlikely. For the time being, at least, the
domestic lead industry appears to be static with regard to major increases in
capacity. This lack of growth means that the new source performance standards
for lead smelters will have no short-term impact on the domestic primary
lead industry.
The possibility always exists, of course, that future conditions in the
lead industry could change and that a new lead smelter would be constructed.
Given this assumption,it would then be expected that the new lead smelter
would be built in Missouri, near the New Missouri Lead Belt. Since the
Missouri standard for sulfur dioxide emissions is 500 ppm from new sources,
this means that the Federal new source performance standard would have no
incremental effect over the Missouri standard. If a new smelter was constructed
in a state that did not have any limitations on sulfur dioxide emissions,then
the total impact upon the industry would be solely due to the Federal new source
performance standard. It can be seen that the incremental impact upon the
domestic lead industry is a function of the existing standards in the state in
which the smelter would be constructed. The Federal new source performance
standard could have no impact in some states and significant impact in other
states, depending upon the standards that apply in the individual states.
6-136
-------
In the event that a new lead smelter was constructed, it is reasonable
to assume that it would have a capacity of approximately 100,000 tons of
pig lead per year. Since the proposed new source performance standards would
preclude the use of a sintering machine without gas recirculation, this means
that the new smelter would employ either recirculating sintering machine
smelting or electric smelting. The additional capital requirements for control
of sulfur dioxide emissions for these two processes, assuming that dual-stage
acid plants without acid neutralization are used as the control equipment,
would amount to $5.0-$5.6MM (refer to Table 6-27). Since a new lead smelter
of 100,000 ton/year capacity would be expected to cost approximately $40-$50MM,
this means that the emission control equipment adds 10-14% to the capital require-
ments. Annual operating costs are estimated to be approximately 0.72-0.75(^/1 b
of lead, or 2.9 - 3.1% of sales at a price level of 24.5 £/lb.
It is felt that the additional capital costs for emission control equipment
could be absorbed by the smelter through a larger borrowing at the time the
smelter is financed. The additional operating costs, however, would probably
not be absorbed at the smelter due to the relatively low profit margins (on
the order of 0.5<£/lb) that are believed to exist at the smelters. It is also
unlikely that a new smelter could pass the additional operating costs forward
to the market in the form of higher prices. Since lead is a commodity item,
the market price is set by the action of the various competitors in the market,
both domestic and foreign, as these competitors respond to the overall demand
for lead. A single competitor cannot unilaterally increase his price. Passing
forward of pollution control costs does not appear to be a viable possibility
for the new lead smelter.
6-137
-------
A mechanism does exist, however, whereby the annual costs of operating
the emission control equipment can be absorbed. This is the mechanism of
passing the control costs back to the mines. It is believed that a level of
backward integration exists in the industry such that this mechanism would be
facilitated. The net effect would be that individual mine profitability would
decrease unless higher grade ore bodies were available to the mines. The net
long-term effect would be that mine reserves would be decreased and the closing
of marginal mines would be accelerated. In summary, it appears that annual
pollution control costs of the magnitude shown above could be passed back to
the mines without a severe disruption of traditional profitability requirements
in the event that a new lead smelter was constructed.
Costs for control of air pollutants are not the only environmental costs
being faced by the domestic lead industry. It has been estimated that capital
requirements for the industry to comply with state water pollution regulations
at existing mines and smelters would amount to $20MM. Annual costs for com-
pliance with the water standards would amount to 0,40^/lb of lead produced.
A study by Arthur D. Little on the economic effect of pollution abatement costs
in the lead industry stated that water pollution costs were more or less uniform
Q
within the industry and would not lead directly to any plant closings. It can
be inferred that these costs would not preclude entry to the domestic lead
industry, either. Arthur D. Little notes, however, that water pollution control
costs could increase dramatically if more stringent standards are required.
Not specifically estimated are costs associated with OSHA or the Mine Safety
Act. These costs are expected to be negligible.
6-138
-------
REFERENCES FOR SECTION 6.3
1. Private communication; Magma Copper Co.; August 1972.
2. Private communication; Bureau of Mines; December 1973.
3. "The Impact of Air Pollution Abatement on the Copper Industry,"
Fluor-utah Engineers and Constructors, Inc., April 20, 1971.
4. "Applicability of Reduction to Sulfur Techniques to the Development
of New Processes for Removing S02 from Flue Gases," Allied Chemical
Industrial Chemicals Division (n6t dated).
5. Private communication.
6. a) "Commercial Experience with An SOp Recovery Process," B.H. Potter
and T.L. Craig, "Chemical Engineering Progress, August 1972, page 53.
b) Federal Register, Vol. 37, No. 55, March 21, 1972.
7. EPA estimate.
8. EPA estimate to cover property taxes, insurance, and capital-related
charges.
9. "Economic Impact of Anticipated Pollution Abatement Costs"; Primary
Copper Industry; Part 1, Executive Summary; A Report to the Environmental
Protection Agency; Arthur D. Little; autumn 1972.
6-139
-------
-------
7. RATIONALE FOR THE PROPOSED STANDARDS
7.1 SELECTION OF SOURCE CATEGORIES
Primary copper, zinc, and lead smelters are among the largest
individual sulfur dioxide emission sources. For example, the domestic
smelting industries had the following emission rates as of mid-1973
from plants of average capacity even after partially controlling sulfur
dioxide discharges:
1. Copper smelters - 550 tons S02/day, 33% control.
2. Zinc smelters - 75 tons S02/day, 68% control.
3. Lead smelters - 59 tons S02/day, 27% control.
Even though the twenty-nine domestic smelters constituted a relatively small
total number of sources, they accounted for approximately 12 percent of
total national sulfur dioxide emissions. In addition, these primary
smelters discharged more than 35,000 tons/year of particulate matter.
For many years, smelters have been publicized as being among the
nation's largest sources of air pollution. This partly resulted from
incidents such as occurred at Trail, British Columbia,where smelter sulfur
dioxide emissions (600 tons SOp/day) were reported as the cause of plant
injuries as far as 52 miles south of the smelter. Three zones of injury
were delineated on the basis of the percentage injury to Ponderosa pine,
Douglas fir, and forest shrubs: in Zone 1 there was 60 to 100% injury;
in Zone 2, 30 to 60% injury; in Zone 3, 1 to 30% injury. Zone 1, in which
injury was acute, extended about 30 miles south of the smelter in a river
valley; Zone 3, at higher elevations, extended 52 miles south of the
smelter and contained trees with relatively slight markings and trees
7-1
-------
suffering from slow but progressive deterioration. Other cases
have been reported in which sulfur dioxide emissions from smelters have
deteriorated or suppressed the growth of trees, shrubs, crops, or other
vegetation. In addition, the development of implementation plans for the
States which contain smelters has further headlined the smelters as being
very large sources of sulfur dioxide emissions which have not been well
controlled.
All smelters will have to comply with some sulfur dioxide emission
limit, promulgated by either a State or EPA, by 1975-1977 to provide for
the attainment of the national ambient air quality standard for sulfur
dioxide. Since the control of sulfur dioxide emissions at some smelters
is currently minimal, it is expected that these smelters will have to
achieve a substantial reduction in sulfur dioxide emissions. Recent
developments in the smelting industry indicate that the stringency or
anticipated stringency of the control requirements has led to industry
consideration of newer smelting technologies which have not previously been
applied in the United States and which are more susceptible to sulfur dioxide
control. In addition to modifying and rebuilding to incorporate these more
modern smelting processes, existing smelters have made plans to employ
emission control systems that have not been widely applied domestically.
However, since the State standards are primarily aimed toward the attain-
ment of specified ambient air quality levels, the resulting smelter modi-
fications need not necessarily reflect the use of best demonstrated technology
in all cases. On the other hand, a new source performance standard
7-2
-------
applicable to smelters would reflect the best emission control capabilities
(considering cost) for new smelters. Since new source performance standards
are applicable to new sources, they may in some cases reflect
the use of new process technologies which are more susceptible to sulfur
dioxide control than existing process technology.
It is expected that two new grass-roots copper smelters (excluding
the Phelps Dodge smelter at Tyrone, New Mexico, which has already
been announced) will be constructed in the United States by 1984.
It is probable that two new zinc smelters will be put into operation
in the period 1975-1977. The domestic lead industry is producing
at less than capacity rates, and future growth in lead consumption
appears slight. As a result, the prospect of future growth by the
addition of new lead smelting capacity appears remote. Even though
the growth potential of copper, zinc, and lead smelters is small
in terms of total numbers of new sources, each new facility is a
very large emitter and can contribute significantly to air pollution
which causes or contributes to the endangerment of public health
or welfare.
7-3
-------
7.2 METHODOLOGY FOR DEVELOPING PROPOSED STANDARDS
EPA Initiated development of the proposed staridards by
contacting domestic smelter operators and reviewing the technical
and trade literature. Subsequently, EPA engineers carried out on-
site inspections of processing and emission control equipment at
all domestic primary copper, zinc, and lead smelters. EPA consulted
with smelter operators during these visits and in joint EPA/American
Mining Congress meetings concerning the development of emission standards.
An evaluation of the information collected from the above sources led
to the conclusions that:
1. All major process gas streams at each type of smelter should
be considered for standards development, in most cases for
sulfur dioxide emissions and in the remaining cases for
particulate emissions.
2. The most difficult control problem would probably be the
treatment of weak sulfur dioxide effluents from some
smelting processes.
3. Some smelting processes, which are available and in use at foreign
smelters, eliminate the generation of weak sulfur dioxide
streams.
4. Some foreign smelters were controlling sulfur dioxide
emissions with double-absorption sulfuric acid plants,
which are more efficient than the single-absorption plants
that were the only ones in domestic operation at that time.
7-4
-------
It was also concluded that the emission control performance of single-
absorption sulfuric acid plants operated at domestic smelters was not
well characterized, particularly with regard to such smelting processes
as copper converting which discharge widely fluctuating off-gas
streams.
A limited EPA emission testing program at domestic smelter sites
was carried out in May and June 1972. Tests of single-absorption
sulfuric acid plants and fabric filters provided indications of the
« performance capabilities of the best domestic sulfur dioxide and
particulate emission control technologies. EPA engineers then
> visited smelters in Europe and Japan to determine the feasibility
of setting standards on the basis of double-absorption sulfuric
acid plants for sulfur dioxide control and on the basis of the newer
smelting technologies which largely eliminate weak sulfur dioxide
effluents.
From October through December 1972 a continuous sulfur dioxide
monitor recorded emissions from a domestic metallurgical single-
absorption acid plant. These data were analyzed to determine
the extent of fluctuations in sulfur dioxide emission concentrations
and to develop methods that would account for these fluctuations
( in a sulfur dioxide emission standard.
Following the visits to smelters in Europe.and Japan, EPA
engineers drafted a technical report which evaluated the applicability
*
of newer smelting process technologies to domestic operations. The
primary purpose of this report was to present the position that
7-5
-------
weak sulfur dioxide streams can he largely eliminated by the
application of these smelting processes. This report was reviewed
by the National Air Pollution Control Techniques Advisory Committee,
the Federal Liaison Committee, and the American Mining Congress
in meetings with EPA in November and December 1972. Subsequently,
the draft report was revised based upon an evaluation of the
numerous comments expressed during these meetings; it is incorporated
into this document as Sections 3, 4 and 6.
Emission control systems are also discussed in the draft
report cited above. Because no double-absorption sulfuric acid
plants or weak-stream sulfur dioxide scrubbing systems were in
operation at domestic smelters prior to late 1972, suitable quantitative
data for the establishment of regulatory sulfur dioxide emission limits
representative of best demonstrated technology were not available.
Consequently, EPA solicited written comments on the expected
performance capabilities of these systems from domestic sulfuric
acid plant vendors, scrubbing system vendors, and scrubbing system
researchers. In addition, EPA performed a detailed analysis
of the continuous sulfur dioxide, single-absorption acid plant
emission data noted above. This analysis showed that long-term
averaging of emission concentrations is an effective method of
masking fluctuations in emission concentrations and arriving at
an emission limit related to acid plant vendor guarantees.
A double-absorption sulfuric acid plant was put into operation
at the ASARCO copper smelter in El Paso, Texas, in late 1972. EPA
7-6
-------
monitored sulfur dioxide emissions from this plant on a continuous
basis during the period June-December 1973. A detailed analysis
of the data from this test demonstrated again the effectiveness
of long-term averaging in masking fluctuations in emission
concentrations. The analysis also provided data on the effect of
acid plant inlet sulfur dioxide concentration on sulfur dioxide
emissions, and the portion of operating time during which alternative
sulfur dioxide emission concentrations are exceeded.
The proposed standards described in this report were developed
after considering numerous alternative smelting processes and ranges
of emission control levels. These alternatives are presented in
Section 6 of this report, where model copper, zinc, and lead smelters
have been analyzed, and control costs have been presented for the
various alternatives. The sulfur dioxide emission limitation contained
in the proposed standards is intended to require the installation of
double-absorption sulfuric acid plants, or other control systems which
achieve an equivalent effluent stream concentration. The specific
value of 650 ppm sulfur dioxide has been based upon monitored
test data for the metallurgical double-absorption sulfuric acid
plant at the ASARCO, El Paso, Texas, copper smelter, modified to
account for the maximum expected inlet sulfur dioxide concentration
produced by smelting processes and for acid plant catalyst deterioration.
It is the judgment of the Administrator that the emission limit
can also be met by the use of scrubbing systems on both strong and weak
sulfur dioxide streams. This conclusion is primarily based upon
7-7
-------
engineering evaluations of several systems, rather than upon emission
data for smelter effluent streams; treated by these systems.
The potential environmental effects of the proposed standards
were investigated. Quantities of potential solid and sludge wastes
resulting from the neutralization of sulfuric acid and the use of
scrubbing systems were determined. A survey was carried out to
identify those disposal methods which can minimize secondary
pollution problems. The energy requirements of the various emission
control systems that can be utilized to comply with the standards
have been estimated and the impact of the standards on the energy
requirements associated with the production of copper, zinc and
lead analyzed. The results are discussed in Section 8.
The development of the proposed sulfur dioxide standards on
the basis of continuous monitoring data has made it possible and
desirable to base compliance on measurements by continuous monitors.
Method 12 for demonstrating the performance of monitors required
by the standards to be installed and operated by affected sources
is included in the proposed standards.
7-8
-------
7.3 SELECTION OF POLLUTANTS
In assessing the environmental impact of each of the processes
for which standards are now being proposed, the quantities of
pollutants emitted from existing smelters were considered. Emission
testing and material balances indicated that significant amounts of
sulfur dioxide or particulates are emitted from each of the selected
affected facilities. Primary copper, zinc, and lead smelters are
among the largest individual sulfur dioxide emission sources.
For example, the domestic smelting industries have the high emission
rates cited in Section 7.1 from plants of average capacity even
after partially controlling sulfur dioxide discharges. In addition,
twenty-nine domestic primary smelters discharge greater than
35,000 tons/year of particulate matter. Because of (1) the
documented evidence that both sulfur dioxide and particulate
matter have caused adverse health effects and adverse welfare
effects,1'^ (2) the large quantities of pollutants involved,
and (3) the large increases in pollutant control that can be
effected, standards to limit emissions of sulfur dioxide and
particulate matter are proposed for copper, zinc, and lead
smelting processes.
7-9
-------
7.4 SELECTION OF AFFECTED FACILITIES
The copper, zinc, and lead smelting Industries are dependent
upon sulfur-bearing ore concentrates as the major raw materials.
Eleven pyrometallurgical processes are used in various configurations
to process these ore concentrates into copper, zinc, and lead.
The basic principle of most of these pyrometallurgical smelting processes
is that the various constituents can be separated by selective
high-temperature chemical reactions such as the reaction of sulfur
with oxygen to produce gaseous sulfur dioxide which is vented from
the process. Additional impurities may either be evolved due
to the high temperatures or entrained in the outlet gases. Because
all of these pyrometallurgical processes can emit significant
quantities of sulfur dioxide or particulate matter, the proposed
standards apply to all eleven of these processes. Each type of
processing equipment and its corresponding emission control
equipment were evaluated in order to determine appropriate standards
for particulate, sulfur dioxide and visible emissions.
The proposed standards do not apply to hydrometallurgical
techniques, because hydrometallurgical processes do not emit
significant quantities of sulfur dioxide or particulate matter.
7-10
-------
7.5 DETERMINATION OF EMISSION LIMITS
7.5.1 Choice of Best Demonstrated Technology
Section 111 of the Clean Air Act requires the establishment
of Federal standards of performance for new stationary sources which
may contribute significantly to air pollution resulting in or
contributing to the endangerment of public health or welfare.
The term new source is defined as a stationary source the construction
or modification of which is commenced after the proposal of
regulations under section 111; modification means any physical
change in, or change in the method of operation of, a source
which increases the amount of any air pollutant emitted by
such source or which results in the emission of any air pollutant
not previously emitted. Such standards of performance are required,
by the Act, to reflect the degree of emission limitation achievable
through the application of the best system of emission reduction
which has been determined to be adequately demonstrated, taking
into account the cost of achieving such reduction. "Adequately
demonstrated" does not mean that the technology must be in actual
use somewhere nor that any existing source be able to meet the
standards based on this technology. However, "adequately demonstrated"
does imply that the control technology relied upon in setting a
standard of performance can be made available, and will be effective
to enable sources to comply with such standards by their effective
date.
7-11
-------
As discussed in Section 7.4, the proposed standards apply to
all eleven copper, zinc, and lead pyrometallurqical orocesses Because
of the significant quantities of sulfur dioxide or particulate
matter that can be emitted from these processes. However, the
proposed standards do not apply to hydrometallurgical processes
because hydrometallurgical processes do not emit significant
quantities of sulfur dioxide or particulate matter. Although
a limited number of smelters may construct hydrometallurgical
processes rather than pyrometallurgical processes in order to
take advantage of the smaller emission potential of hydrometallurgical
processes, hydrometallurgical processes for production of copper,
zinc, or lead have been applied commercially only to oxide ores
or to ores consisting predominately of oxides with some sulfides
present. To date, no hydrometallurgical process has been successfully
commercialized for the treatment of copper, lead, or zinc sulfide
ores, although processes are currently under development and the
construction of one hydrometallurciical copper extraction facility
has been announced. Thus, in the judgment of the Administrator,
it has not been demonstrated that hydrometallurgical processes are
of sufficiently broad applicability to justify basing the proposed
standards solely on these processes. Accordingly, the following
sections discuss the rationale of developing standards for pyro-
metallurgical processes only.
7.5.1.1 Sulfur Dioxide Emissions in Strong Streams
For the purposes of this discussion, "strong sulfur dioxide streams"
refers to streams which contain more than 3.5-4J3% sulfur dioxide. The
7-12
-------
characterization of effluents in terms of these sulfur dioxide
concentration levels depends upon the fact that conventional
sulfuric acid plants of single-absorption and double-absorption
design are normally economically feasible only on streams more
concentrated than 3.5% and 4.0% sulfur dioxide, respectively.
Single-absorption sulfuric acfd plants have been utilized at
domestic smelters for a number of years, but double-absorption plants
have only recently been applied (late 1972). Dimethyl aniline (DMA)
scrubbing systems and ammonia scrubbing systems are also used on
smelters' strong sulfur dioxide streams and thus, as discussed in
Section 4.3, are considered to be adequately demonstrated sulfur
dioxide control technologies for smelters' strong sulfur dioxide
streams. Each of these systems is capable of high-efficiency
(greater than 95%) control of sulfur dioxide emissions. Elemental
sulfur recovery plants can also be used to control sulfur dioxide
emissions, but the tail gas stream must be further processed by ?
scrubbing system, such as DMA or sodium sulfite-bisulfite, in orc1^
to reduce the sulfur dioxide emission concentrations to the leveH
attainable by sulfuric acid plants. In addition, streams which
contain less than 10% sulfur dioxide and greater than 5% oxygen
cannot be processed directly in elemental sulfur recovery plants
rather, the sulfur dioxide must first be concentrated by a scrutr ^r
system, such as DMA. Each of these sulfur dioxide control system.
provides high-efficiency particulate control since proper operator,
requires that particulate matter be removed to a degree consist?> '
with best available particulate control technology prior to SUIHS
dioxide removal. Thus, the choice of best control technology fo>-
7-13
-------
strong sulfur dioxide streams is primarily a choice of the best
sulfur dioxide removal capabilities, considering cost of such
removal, for these systems.
From the viewpoint of emission control, the primary distinction
between single-absorption acid plants and the other sulfur dioxide
control systems (double-absorption acid plants and elemental sulfur
plants with tail-gas scrubbing) is that the latter systems are
capable of reducing emission rates by 70-80% of those from single-
absorption sulfuric acid plants. Consequently, these other control
systems can be viewed as providing a small incremental increase
in sulfur dioxide control efficiency from approximately 97 to 99.5%.
The capital investment and unit emission control costs which
are calculated for model smelters in Section 6 increase in the following
order: (1) single-absorption sulfuric acid plants, (2) double-
absorption sulfuric acid plants, (3) scrubbing systems, and (4) elemental
sulfur plants with tail-gas scrubbing. The capital investment for
double-absorption sulfuric acid plants is about 20% greater than
that for single-absorption sulfuric acid plants, but the unit
emission control costs are considered to be acceptable in both cases.
For example, Table 6-12 shows that typical control costs for
single-absorption and double-absorption sulfuric acid plant control
of an electric furnace/converter copper smelter are, respectively,
1.68 and 1.87 cents per pound of copper produced, assuming acid
is sold at zero netback to the smelter. In terms of control
costs referred to the quantity of sulfur dioxide removed, the costs
7-14
-------
are 0.72 and 0.79 cents per pound, respectively, of sulfur dioxide
controlled. As discussed in Section 6.1, these costs are not
unreasonable compared to the average cost of emission control of
about 3 cents per pound of copper which will be experienced at
existing domestic copper smelters to comply with the sulfur dioxide
national ambient air quality standard. Similarly for zinc smelters,
Table 6-19 shows that the costs of single-absorption and double-
absorption sulfuric acid plant control of the zinc roaster are
0.70 and 0.78 cents per pound of zinc, respectively, assuming acid
is sold at zero netback to the smelter. Likewise for lead smelters,
Table 6-27 shows that the costs of single-absorption and double-
absorption sulfuric acid plant control of strong sulfur dioxide
streams from lead sintering machines are 0.66 and 0.75 cents per
pound of lead, respectively, assuming acid is sold at zero netback
to the smelter. As discussed in Sections 6.2 and 6.3, the costs
of double-absorption sulfuric acid plant control of these strong
stream effluents are not unreasonable for zinc and lead smelters.
Table 6-12 also shows that, for approximately the same overall
level of sulfur dioxide control, the unit emission control costs for
DMA scrubbing and DMA scrubbing combined with elemental sulfur recovery
are 3.6 and 4.8 cents per pound of copper, respectively, for control
of an electric furnace/converter copper smelter as compared to 1.9 cents
per pound of copper for double-absorption acid plant control. Similar
results are obtained for lead and zinc smelters. Thus, the choice of
7-15
-------
best demonstrated technology (considering cost) is limited to single-
absorption and double-absorption sulfurid acid plants because the
other control systems have increased costs with no additional
control of sulfur dioxide emissions. However, this limitation
does not restrict a smelter from applying other control systems
where special circumstances warrant.
The smelting industry considers double-absorption acid plants
to be the best demonstrated control systems, and a trend toward
the use of double-absorption rather than single-absorption metallurgical
sulfuric acid plants has already been established by the startup
of the first two domestic double-absorption acid plants within the
past year and by the initiation of construction or the announced
plans for construction of three other double-absorption acid
plants. In addition, some State regulations already require the
use of double-absorption acid plants. Thus, considering the current
trend toward double-absorption acid plants, the additional 70-80%
reduction in sulfur dioxide emissions discharged from double-
absorption acid plants over single-absorption acid plants, and the
EPA analyses of emission control costs of double-absorption acid
plants which indicate that the costs are reasonable, the Administrator
has determined that emission limits should reflect the sulfur dioxide
control capabilities of double-absorption sulfuric acid plants.
7-16
-------
7.5.1.2 Sulfur Dioxide Emissions in Weak Streams
For the purpose of this discussion, "weak sulfur dioxide streams"
refers to streams which contain less than 3.5 - 4.0% sulfur dioxide.
Each category of primary nonferrous smelters subject to the proposed
standards involves at least one weak sulfur dioxide stream. These
weak streams are discharged from reverberatory smelting furnaces
at copper smelters, sintering machines at zinc smelters, and
sintering machines and blast furnaces at lead smelters. With
one exception, all fifteen domestic copper smelters now operate
the reverberatory type of furnace. Also, three of the six domestic
zinc smelters utilize sintering machines which discharge weak
sulfur dioxide streams, and all six domestic lead smelters operate
sintering machines and blast furnaces which discharge weak sulfur
dioxide streams. Section 4.3 concludes that scrubbing systems
have been commercially demonstrated on a variety of non-smelter
weak sulfur dioxide streams and also on some smelter weak sulfur
dioxide streams. For example, scrubbing systems are operating
on a 1.5 to 2.5% sulfur dioxide stream discharged from a lead
sintering machine, 1.5% sulfur dioxide streams from Glaus
sulfur recovery plants, 3000-5000 ppm sulfur dioxide tail gas streams
from sulfuric acid plants, 2000-6000 ppm sulfur dioxide streams
from blast furnaces at secondary lead smelters, and various low
sulfur dioxide concentration streams from power plant steam generators,
Although no copper reverberatory furnace or zinc sintering machine
7-17
-------
weak sulfur dioxide stream has yet been controlled on a long-term
basis, a DMA scrubbing unit has been put into operation to control
the weak sulfur dioxide stream from a reverberatory furnace at
the Phelps Dodge copper smelter at Ajo, Arizona.
The most significant factor limiting the application of scrubbing
systems to weak sulfur dioxide streams within the primary copper,
zinc and lead smelting industry is the cost. Sulfur dioxide control
of the weak sulfur dioxide streams from copper reverberatory
furnaces, lead or zinc sintering machines, or lead blast furnaces
results in emission control costs which are considered unreasonable
in most cases. For example, Table 6-12 shows that the cost of
controlling a weak sulfur dioxide stream from a copper reverberatory
furnace with DMA scrubbing, while controlling the strong sulfur
dioxide stream from the converter with a double-absorption
sulfuric acid plant, would be 4.4 cents per pound of copper.
This cost is significantly greater than the 3 cents per pound
of copper cost which has been determined to be the maximum
increase that would allow domestic copper smelters to remain
competitive in the world market. Similarly for zinc smelting,
Table 6-19 shows that the cost of controlling the weak sulfur
dioxide stream of a zinc sintering machine with DMA scrubbing,
while controlling the strong sulfur dioxide stream of a zinc roaster
with a double-absorption sulfuric acid plant, would be 3.2 cents
per pound of zinc, assuming the acid is sold at zero netback to
the smelter. Further* for lead smelting Table 6-27 shows that
7-18
-------
the cost of controlling the weak sulfur dioxide streams of a
lead sintering machine and blast furnace with DMA scrubbing,
while controlling the remaining strong sulfur dioxide stream from
the sintering machine by a double-absorption acid plant, would
be 3.6 cents per pound of lead, assuming the acid is sold at
zero netback to the smelter. As discussed in Sections 6.2 and 6.3,
respectively, these costs are considered unreasonable in most
cases for zinc and lead smelters. Accordingly, EPA investigated
* whether there are process changes which can be utilized to
eliminate the generation of weak sulfur dioxide streams at
newly constructed smelters.
A substantial portion of the development program for the
proposed standards focused on identifying those situations where
weak sulfur dioxide streams can be eliminated by process changes.
It has been determined that two copper smelting processes (electric
furnace smelting and flash smelting) which discharge only strong
sulfur dioxide streams are demonstrated smelting technologies
and that together they are applicable to the full range of
domestic copper smelting operations. One electric copper smelting
furnace is already in use in the U.S., and construction of a
% second electric furnace has recently been completed. In addition,
the construction of a third electric furnace has been announced.
* The construction of a flash furnace is currently underway. The
4
proposed standards are based primarily upon the application of these
7-19
-------
smelting processes. The alternative of structuring the standard
to allow the use of new conventional reverberatory smelting furnaces
would essentially mean that sulfur dioxide emissions from smelting
furnaces should not be controlled because of the unreasonable costs
of presently available scrubbing systems for weak sulfur dioxide
streams within this industry. The difference in control levels
achieved would be large. For example, Table 6-12 shows calculated
sulfur dioxide control levels of 99.5 percent for an electric furnace
smelter which meets the proposed standard versus 70-80 percent „
for a reverberatory furnace-converter smelter or a roaster-
reverberatory furnace-converter smelter, which emits an uncontrolled ,
weak sulfur dioxide stream from the furnace while applying a
double-absorption sulfuric acid plant to the streams of
the converters or the roasters and converters. The corresponding
approximate sulfur dioxide emission rates are 3, 180, and 120 tons
per day, respectively.
Although the proposed standard for copper smelters is based
primarily upon the use of electric or flash smelting processes, the
proposed standard can be achieved using the reverberatory furnace
process by blending the reverberatory furnace gases with converter
or converter and roaster gases and treating the combined gas stream
with a double-absorption sulfuric acid plant. A smelter in Yugoslavia
is currently changing its procesj; so that the gases from the *
reverberatory furnace will be blended with the gases from roasters
and converters. The combined gas; stream will be a strong sulfur t
7-20
-------
dioxide stream that will be treated with sulfuric acid plants.
The limitations of this technique are similar to those of flash
furnaces but the technique does offer smelters some flexibility.
The Administrator recognizes that copper smelters have traditionally
increased production by incremental expansions of existing facilities,
in addition to constructing new grass-roots smelters. Some incremental
expansions would be classified as modifications under section 111
of the Act and would be subject to new source performance standards.
Consequently, in developing the proposed standards the impact on
modified smelters has been considered. The primary difficulty
in accommodating both grass-roots copper smelters and modified
existing copper smelters within a single sulfur dioxide emission
limitation is the control of increased emissions from modified
reverberatory furnaces. As stated above, the costs of controlling
weak sulfur dioxide streams from reverberatory furnaces is
considered unreasonable in most cases, but grass-roots smelters
can adopt alternative copper smelting processes which do not
generate weak sulfur dioxide streams.
Future incremental expansions of existing copper smelters
may be restricted somewhat, in comparison with past practices,
by emission limitations approved or promulgated under 40 CFR Part 52
to meet national sulfur dioxide ambient air quality standards.
•
However, some existing copper smelters will still be able to expand
production within the limits of these requirements. Where these
requirements permit, significant expansions are technically feasible
7-21
-------
without increasing reverberatory furnace emissions. For example,
green-charge reverberatory furnace smelters,which account for 8
of the existing 15 domestic copper .smelters,can be converted to
calcine-charge reverberatory furnace smelting to achieve substantially
increased production without an increase in furnace emissions. Existing
copper smelters can also convert to smelting processes which
do not employ reverberatory furnaces and can be controlled without
using weak sulfur dioxide control devices. Two existing
smelters are planning conversion:;, one existing smelter is
installing additional capacity, and one new grass-roots smelter
is under construction using processes of this type. Consequently,
it appears that a new source performance standard based on the
use of copper smelting processes that generate only strong
sulfur dioxide streams allows flexibility for expanding some
existing smelters. However, other types of expansions, for example
the widening of a reverberatory furnace to accommodate existing
excess capacity of roasters, would increase reverberatory furnace
emissions. The increased furnace emissions could be compensated
by a corresponding decrease in emissions from other processing
units producing strong sulfur dioxide streams at the smelter
provided it has not been necessary to control emissions from
all these units to comply with the emission limitations approved
or promulgated under 40 CFR Part 52. That Is, some expansions which
increase reverberatory furnace emissions can be accomplished
without increasing total sulfur dioxide emissions from an entire
7-22
-------
t
*
copper smelter. To allow this type of expansion, an exemption
for existing reverberatory furnaces is included in the proposed
standards. Specifically, any physical or operational change
to any existing reverberatory smelting furnace which results
in an increase in sulfur dioxide emission rate from the furnace
is not considered a modification to the furnace provided the
combined total sulfur dioxide emission rate from all existing
and affected facilities at the copper smelter does not increase.
The baseline sulfur dioxide emission rate is that allowed under
implementation plans approved or promulgated under 40 CFR Part 52.
On the basis of the above factors, it is the judgment
of EPA that the proposed standards will allow expansion of
some existing copper smelters. EPA recognizes, however, that
the economics of incremental expansions are case-specific,
depending upon the configuration of the existing smelting
process, existing emission control devices, the level of control
required to comply with national ambient air quality standards,
and a number of economic factors. Accordingly, EPA has funded
a contract study to Arthur D. Little, Inc.,(Cambridge, Massachusetts)
to examine in more detail several issues concerning the proposed
standard for copper smelters, including the impact of the proposed
standard on modified copper smelters. The results of this study
will be treated as comments on the proposed standard, and the
Administrator will consider the results in determining whether the
7-23
-------
proposed standard should be revised prior to promulgation. The
results of the study will also be made available for public
comment during the comment period following proposal.
The smelting industry expressed strong objections, during
the development of the proposed standards, that the electric
and flash smelting processes have significant limitations. The
industry indicated that electric furnace smelting, even though
fully as flexible a production method as conventional reverberatory
smelting processes now in use, is not viable in some cases because
of the non-availability of electric power. The industry also argued
that a significant portion of domestically processed copper
concentrates cannot be handled by flash furnaces, either because
of an insufficient amount of sulfur or excess amounts of lead
and zinc in the concentrates. However, EPA surveys show, as
discussed in Section 3, that approximately 95 percent of domestic
ore concentrates have sufficient sulfur to permit the use of flash
smelting and that more than 96 and 99 percent of domestic copper
concentrates are sufficiently limited in, respectively, lead
and zinc content to permit the use of flash furnaces without
encountering major problems in the heat recovery facilities.
Other volatile metals, such as arsenic, antimony, beryllium,
cadmium, and tin, which could cause similar problems, are also
sufficiently limited in domestic ore concentrates to permit
the use of flash smelting.
t
*
7-24
-------
The Industry also raised the point that smelters incorporating
flash furnaces are limited in the amounts of secondary copper scrap
and copper precipitates (produced by acid leaching operations) which
they are able to process, compared to conventional domestic smelters
incorporating reverberatory furnaces. Flash furnaces normally
produce high-grade copper mattes containing 45-65 percent copper,
whereas low-grade mattes of 30-40 percent copper are normally
produced at most domestic smelters. The increased matte grade
leads to reduced copper converter blowing times and lower converter
temperatures, thus reducing significantly the amounts of secondary
copper scrap and copper precipitates which can be processed in the
copper converters.
The recovery of copper from secondary copper scrap and copper
precipitates at primary copper smelters is significant and accounts
for about 30 percent of the copper produced by the domestic primary
copper smelting industry. However, this limitation of the flash
smelting process is not likely to be as serious as it first appears.
Not every primary smelter currently operating processes significant
amounts of secondary copper scrap or copper precipitates. Thus,
it is reasonable to assume that not every new smelter will have to
process significant amounts of secondary copper scrap or copper
precipitates. In these cases, this limitation of flash smelting
would be of little concern. Also, there are alternatives to
processing at a primary copper smelter by which copper can be
recovered from secondary copper scrap and copper precipitates.
7-25
-------
For example, the domestic secondary copper smelting industry
currently recovers about as much copper from secondary copper
scrap as the primary copper smelting industry. Specifically,
the secondary copper smelting industry accounts for 45 percent
of the copper recovered from secondary scrap and the primary
copper smelting industry accounts for the remaining 55 percent.
It should also be noted that, by the industry's own admission,
smelters employing electric smelting furnaces would not be faced
with these limitations. Consequently, if a new copper smelter
were required to process significant amounts of secondary copper
scrap and copper precipitates, electric smelting rather than flash
smelting furnaces could be employed.
With regard to copper precipitates, a number of commercial
installations in operation in the United States recover copper from
copper leaching operations by leaching/solvent extraction/electrowinning,
rather than leaching/precipitation followed by smelting at a primary
copper smelter. Currently these installations account for about
20 percent of the copper recovered from copper leaching operations,
while the primary smelting industry accounts for the other 80 percent.
Consequently, this limitation of flash smelting may result in the
expansion of the secondary copper smelting industry and the
use of leaching/solvent extraction/electrowinning in place of
leaching/precipitation/smelting,, rather than limit the recovery of
copper from leaching operations within the United States or limit
the application of flash smelting.
7-25
-------
Finally, 1n the last stages of the development of the proposed
standards by EPA, the industry raised the point that smelters employing
flash smelting furnaces and processing copper concentrates containing
high levels of impurities such as arsenic, antimony, and bismuth
might produce blister copper containing higher levels of these
impurities than if the concentrates were processed in conventional
domestic reverberatory smelting furnaces. As mentioned above, the
increased grade of matte produced by a flash smelting furnace leads
to reduced converter blowing time and lower converter temperatures.
This was cited by the industry as leading to decreased impurity
elimination by the copper converters and thus leading to the production
of blister copper of higher impurity levels than that produced by
conventional domestic smelters employing reverberatory smelting
furnaces. However, the industry did not supply EPA data
or information showing that the levels of these impurities are so
high in a significant portion of domestic copper concentrates
and other copper smelter feed materials that this potential
problem would constitute a major limitation to the use of the
flash smelting process.
Furthermore, a review by EPA of the various techniques for
the refining of blister copper, as discussed in Section 3, indicates
that a number of these techniques could be applied to eliminate
some increased levels of these impurities. As also discussed
in Section 3, blending of high-impurity concentrates with concentrates
containing normal or minimal levels of these impurities could be
7-27
-------
utilized to alleviate these problems to some extent. In addition,
it should be noted here, as above, that by the industry's own
admission smelters employing electric smelting furnaces would not
be faced with these problems. Consequently, if a new copper smelter
were required to process copper concentrates containing higher levels
of impurities than could be successfully processed by flash smelting,
electric smelting could be employed.
As mentioned above, these points concerning the limitations of
smelters employing flash smelting furnaces, with regard to the processing
of concentrates containing high levels of various impurities, were
raised during the final stages of developing the proposed standards.
Preliminary investigations into this area and into the general
availability of electrical power for smelters incorporating
electric smelting furnaces indicated that the flash smelting
process is applicable to the major portion of domestic copper
concentrates and that electrical power will be available in the
western United States for those new copper smelters which might
utilize electric smelting furnaces. However, EPA has funded
a contract study to Arthur D. Little, Inc., (Cambridge, Massachusetts)
to independently examine this situation in greater detail. The
study is to assess the availability and cost of electrical power
for new copper smelters employing electric smelting furnaces;
to quantify the limitations of the flash smelting process in
comparison with the conventional domestic reverberatory furnace
smelting process; and to examine the associated economic impact
7-28
-------
of the proposed standards, including the impact on modified
copper smelters. The results of the Arthur D. Little study will
be treated as comments on the proposed standards, and the
Administrator will consider the results in determining whether
the proposed standards should be revised prior to promulgation.
On the basis of the information available at this time,
the choice of the best adequately demonstrated emission reduction
system for weak sulfur dioxide streams at copper smelters (considering
cost) can be made from the following alternatives:
(1) utilization of the reverberatory furnace with no control
of the weak sulfur dioxide stream, while applying a double-
absorption sulfuric acid plant to the sulfur dioxide stream
of the converters or the roasters and converters, to
obtain 70-80% overall sulfur dioxide control at a cost
of 1.6 cents per pound of copper;
(2) utilization of a scrubbing system to control the weak
sulfur dioxide stream of the reverberatory furnace, while
applying a double-absorption sulfuric acid plant to the
sulfur dioxide stream of the converters or roasters and
converters, in order to obtain 98.5% overall sulfur dioxide
control at a cost of 4.4 and 3.4 cents per pound of
copper, respectively.
(3) utilization of electric smelting to eliminate weak sulfur
dioxide streams, while applying a double-absorption sulfuric
acid plant to the blended strong sulfur dioxide stream of
7-29
-------
the electric furnace and the converters, 1n order to obtain
99.5% overall sulfur dioxide control at a cost of 1.9 cents
per pound of copper; and
(4) utilization of flash smelting to eliminate weak sulfur
dioxide streams while applying a double-absorption sulfuric
acid plant to the blended strong sulfur dioxide stream
of the flash furnace arid the converters, in order to obtain
99.5% overall sulfur dioxide control at a cost of 1.6 cents
per pound of copper. »
#
All of the above costs assume that the acid is sold at zero netback
to the smelter. As discussed in Section 6.1, the cost of each
1
of the above alternatives, except for scrubbing of the weak
sulfur dioxide stream from the reverberatory furnace, is reasonable
when compared to the allowable increase of 3 cents per pound of
copper. Because the costs of control for alternatives (1), (3),
and (4) are approximately the same, the choice can be based on the
degree of sulfur dioxide control. The difference in control levels
achieved would be large., Either the electric smelting or flash
smelting alternative would result in 99.5% overall control of
smelter sulfur dioxide emissions, whereas the uncontrolled reverberatory
furnace alternative would result in only 70-80% overall sulfur
4
dioxide control. The corresponding approximate sulfur dioxide
emission rates are, respectively, 3 and 180-120 tons per day.
^
After due consideration of the points outlined above, it is »
the determination of the Administrator that the electric and the
7-30
-------
flash furnace smelting processes, In conjunction with double-absorption
sulfuric acid plants, constitute the best systems of copper smelter
emission reduction, considering cost, which have been adequately
demonstrated.
In developing the proposed standards for sulfur dioxide emissions
from zinc smelters, both the electrolytic zinc extraction process which
generates no weak sulfur dioxide streams and those pyrometallurgical
processes which conventionally discharge a weak sulfur dioxide stream
from sintering machines were considered. When roasting of zinc concen-
trates precedes sintering, as practiced at three of the four domestic non-
electrolytic zinc smelters, the sintering machine effluent typically
contains 3-7 percent of the smelter input sulfur at a concentration of
400-3000 ppm sulfur dioxide. As stated above and in Section 6.2, the
high cost (3.2 cents per pound of zinc, assuming acid sold at zero netback
to smelter) of scrubbing weak sulfur dioxide emissions from a sintering
machine, while applying a double-absorption acid plant to the roaster
stream, was judged to be unreasonable when compared to the zinc smelter
profit margin of 0.5 cent p*r pound of zinc.
The electrolytic process produces higher purity, more expensive zinc
than is required by the end uses of greater than 50 percent of the U.S.
zinc consumption. Some uses such as galvanizing even require the presence
of impurities, and thus necessitate debasing of electrolytically produced
zinc at an additional cost of 0.5 cent per pound of zinc. Adding this
additional co*t of 0.5 cent per pound of zinc to the cost of double-
absorption sulfuric acid control of the roaster sulfur dioxide stream,
7-31
-------
as shown in Table 6-19, results in a total control cost of 1.3 cents per
pound of zinc. As discussed in Section 6.2, this cost is not reasonable
when compared to the zinc smelter profit margin of 0.5 cent per pound
of zinc. On the other hand, the non-electrolytic zinc smelting process
accommodates the two major types of reduction furnaces which individually
produce intermediate-grade zinc and the lower (Prime Western) grade zinc
for end uses such as galvanizing.
The Robson roast-sintering process was also investigated to determine
its feasibility for elimination of the weak sulfur dioxide stream by
internally recirculating the weak sulfur dioxide stream to the areas of
the combined roast-sintering machine where the primary roasting reaction
takes place. The use of recirculation of the weak sulfur dioxide stream
requires the installation of a high-efficiency particulate-removal system
in order to prevent recapture of the lead and cadmium impurities in the
sinter bed. The Robson roast-sintering process, while using gas recircu-
lation, is basically suited only for the production of sinter to be used
in the horizontal and vertical retort furnaces. An exceptionally hard and
strong sinter is required for eleotrothermic furnace reduction, and there
is some doubt that even briquetting of the product sinter of the Robson
process can produce an acceptable sinter for the electrothermic furnace.
Thus, if the standards were based solely on the capabilities of the Robson
technique, the effect would be the prohibition of a. significant modern,
versatile reduction technique, the electrothennic furnace, which produces
over 25% of the domestic zinc production. In addition to the technical
7-32
-------
shortcomings associated with the Robson process, the cost of 1.2 cents per
pound of zinc for double-absorption acid plant control (not including the
cost of a high-efficiency particulate-collection system for the recycle
stream) is 50% greater than the cost for double-absorption acid plant
control of the strong sulfur dioxide streams of conventional roasting
and sintering smelters, despite only a 2-1/2% to 6% increase in overall
smelter sulfur dioxide control.
After due consideration of the shortcomings of the electrolytic
zinc extraction process and the Robson roast-sintering process discussed
above, the Administrator has determined that these processes
have not been demonstrated to be of sufficiently broad applicability to
justify basing the proposed standards solely on these processes. According-
ly, the proposed standards do not specify a sulfur dioxide emission limi-
tation for sintering machines. However, best technology (considering costs)
does include the control of roaster sulfur dioxide streams. Thus, the
proposed standards require the equivalent of double-absorption sulfuric
acid plant control for roasters. Also, any sintering machine which
emits more than 10 percent of the smelter input sulfur (as sulfur dioxide)
will be subject to the same sulfur dioxide standard as zinc roasters.
This ensures that sintering machines which are operated simultaneously
as roasters, and which have been judged to be capable of generating strong
sulfur dioxide effluents, will be controlled to the level required on
all other strong streams.
In developing the proposed standards for sulfur dioxide emissions
from lead smelters, the following processes were considered: (a) the
conventional process that does not use sintering machine gas recirculation,
7-33
-------
(b) the similar process that includes sintering machine gas recirculation,
and (c) the electric furnace-converter process. In the first instance,
the sintering machine effluent is either a single weak sulfur dioxide
stream, or a single strong sulfur dioxide stream from the front of the
machine and a single weak sulfur dioxide stream from the back. If the
sintering machine effluent is split, the weak sulfur dioxide stream
typically contains 20 percent of the smelter input sulfur. Gas recircu-
lation in the second process perm'ts the attainment of a single strong
sulfur dioxide discharge from the sintering machine. Both of the first
two processes discharge a weak sulfur dioxide stream, containing approxi-
mately 7 percent of the smelter input sulfur at a gas stream concentration
of 500-2500 ppm sulfur dioxide, from blast furnaces. The third process,
using an electric furnace and converters, is the only demonstrated lead
smelting process which has been identified to be capable of eliminating
all weak sulfur dioxide streams. However, this process has to date been
used only at a single foreign smelter, and no sulfur dioxide control has been
applied to the converters. Further, the electric furnace process has not
yet handled concentrates containing less than 65 percent lead, whereas
domestic concentrates typically contain 55 percent lead.
In the judgment of the Administrator, it has not been demonstrated
that the electric furnace process is of sufficiently broad applicability
to justify basing the proposed standards solely on this process. Thus,
the choice of the best adequately demonstrated emission reduction system
for lead smelters (considering cost) can be made from the following
alternatives:
7-34
-------
(1) utilization of a conventional sintering machine with no control
of the weak sulfur dioxide streams of the sintering machine or
blast furnace, while applying a double-absorption sulfuric acid
plant to the strong sulfur dioxide stream of the sintering
machine, in order to obtain 68.5% overall sulfur dioxide control
at a cost of 0.5 cent per pound of lead;
(2) utilization of a scrubbing system to control the weak sulfur
dioxide stream of a conventional sintering machine with no
control of the weak sulfur dioxide stream of the blast furnace,
T»
while applying a double-absorption sulfuric acid plant to the
strong sulfur dioxide stream of the sintering machine, in order
f
to obtain 89% overall sulfur dioxide control at a cost of 3.1
cents per pound of lead;
(3) utilization of a scrubbing system to control the weak sulfur
dioxide streams of a conventional sintering machine and blast
furnace, while applying a double-absorption acid plant to the
strong sulfur dioxide stream of the sintering machine, in order
to obtain 96.5% overall sulfur dioxide control at a cost of 3.6
cents per pound of lead;
(4) utilization of a recirculating sintering machine to eliminate
the weak sulfur dioxide stream of the sintering machine, while
k
applying no control to the weak sulfur dioxide stream of the
blast furnace, and while applying a double-absorption acid plant
*
« to the strong stream of the sintering machine, in order to obtain
91% overall sulfur dioxide control at a cost of 0.7 cent per
k
pound of lead; and
7-35
-------
(5) utilization of a recirculating sintering machine to eliminate
the weak sulfur dioxide stream of the sintering machine, while
applying a scrubbing system to the weak sulfur dioxide stream of
the blast furnace, and while applying a double-absorption acid
plant to the strong stream of the sintering machine in order to
obtain 98.5% overall sulfur dioxide control at a cost of 1.8
cents per pound of lead.
All of the above costs assume that the acid is sold at zero netback to
the smelter. As discussed in Section 6.3, the costs of alternatives (2),
(3), and (5), all of which include scrubbing of weak sulfur dioxide streams,
are not reasonable, but the costs of control for (1), conventional sintering,
and (4), recirculating sintering, can be borne by the lead smelting industry.
The control cost of the recirculating sintering machine option is approxi-
mately 50% greater than the control cost of conventional sintering, but the
overall degree of sulfur dioxide emission control is increased 33%. After
due consideration of the points outlined above, the Administrator has
determined that the proposed standards should be based on the generation
of a strong sulfur dioxide sintering machine discharge, thereby effectively
requiring sintering machine gas recirculation. Accordingly, the proposed
standards require the equivalent of double-absorption sulfuric acid plant
control for sintering machines, electric furnaces, and converters.
7.5.1.3 Particulate Emissions
Particulate emissions are generated by several primary copper, zinc,
and lead smelting processes. However, those processes which use sulfuric
7-36
-------
acid plants, elemental sulfur plants, or scrubbing systems to control
smelter sulfur dioxide emissions simultaneously control particulate
emissions because proper operation of these sulfur dioxide removal systems
requires prior cleaning of the sulfur dioxide feed stream by the best
available particulate control technology. The proposed sulfur dioxide standards
require the equivalent of double-absorption sulfuric acid plant control
on the effluents from (a) copper roasters, smelting furnaces, and converters,
(b) zinc roasters, and (c) lead sintering machines (for the gases which
pass through the sinter bed), electric smelting furnaces, and converters.
The only sources which emit significant particulate streams that are not
also required to control sulfur dioxide emissions to the levels equivalent
to sulfuric a6td plant control are copper dryers, zinc sintering
machines, and lead blast furnaces, dross reverberatory furnaces, and
sintering machines (discharge end). Thus, explicit standards for
particulate emissions from these sources are proposed.
As discussed in Section 4, fabric filtration is one of the most
efficient (greater than 99.9% by mass, on standard dusts) methods used
for the collection of particulate matter from gas streams. Currently,
baghouses containing industrial fabric filters are used for particulate
control on all of the blast furnace operations and five of the six sinter-
ing operations within the primary domestic lead smelting industry, on one
of the three domestic primary zinc sintering operations, and on the
copper concentrate dryer of an electric furnace smelter which will
undergo startup in the near future. The costs of baghouse control
for these operations are not unreasonable for the primary zinc and
7-37
-------
lead smelting industries. In fact, the economic return due to the
use of baghouses for by-product recovery offsets the emission control
costs in most cases, as evidenced by the widespread use of baghouses
within the primary lead and zinc smelting industry before the advent
of air pollution control regulations. Thus, the Administrator has
determined that the proposed standards for particulate matter should
require the equivalent of baghouse control.
7-38
-------
7.5.2 Quantitative Emission Limits
7.5.2.1 Sulfur Dioxide
Several methods of specifying sulfur dioxide emission
limitations were considered, including sulfur dioxide concen-
tration of an emission stream, percentage recovery of input sulfur to
a smelter, and mass emission of sulfur dioxide per unit of
metal or unit of intermediate material produced.
The performance of a sulfuric acid plant or other sulfur
dioxide control device can be characterized by the efficiency
of sulfur dioxide capture. For a sulfuric acid plant, the
efficiency can be expressed in terms of mass of sulfur dioxide
emitted per unit of sulfuric acid produced, or in terms of plant
inlet and outlet sulfur dioxide concentrations. In practice,
acid plant vendors frequently specify performance in terms of
a guaranteed maximum outlet sulfur dioxide concentration, based
upon inlet sulfur dioxide concentration being in.a stated range.
Therefore, the measurement of outlet sulfur dioxide concentration
from a metallurgical acid plant is a means of assessing the
effectiveness of the plant in controlling sulfur dioxide emissions.
The availability of sulfur dioxide concentration monitors
affords a convenient method of monitoring outlet concentration,
and thereby plant performance, on a continuous basis.
The development of a sulfur dioxide emission limitation
in terms of percentage recovery of input sulfur to a smelter
7-39
-------
involves a knowledge of both the efficiency of control devices
in capturing the sulfur dioxide delivered to the devices and
the distribution of the input sulfur among several output
material flow streams from the smelter. Sulfur enters a smelter
primarily as a constituent of the concentrates to be smelted.
Sulfur typically leaves a smelter by several routes such as:
(a) sulfur contained in by-products of control devices, for
example, sulfuric acid; (b) sulfur discharged to the atmosphere,
either controlled or uncontrolled, through stacks; (c) sulfur
discharged to the atmosphere as fugitive emissions; and (d) sulfur
contained in slags, or metal-bearing products or by-products.
To develop a quantitative percentage sulfur recovery limitation,
it would be necessary to determine sulfur mass balances at
smelters. Representatives of the smelting industry have indicated
to EPA that in their experience sulfur mass balances can be
resolved only to within 20-40 percent of the input sulfur.
Even if more accurate methods were developed and percentage
sulfur recovery limitations were set, the monitoring of smelter
operation would be relatively complicated by comparison with
monitoring only the concentration of effluent sulfur dioxide
streams. It would be necessary to determine the total mass of
sulfur contained in at least two material flow streams over an
appropriate interval of time, for example,in the concentrate feed
stream and in the sulfur-containing material produced by a control
device. In general, it would be necessary to monitor more than
7-40
-------
two streams to close the sulfur mass balance, for example,to account
for sulfur contained in slags. If an air emission stream were
monitored in determining percentage sulfur recovery, it
would be necessary to determine the mass rate of flow of the
stream in addition to the sulfur dioxide concentration.
A production-based emission limitation, expressed as
mass emission of sulfur dioxide per unit of material produced,
must account for variations in the sulfur content of the raw
materials processed per unit of material produced by a smelter.
For example, copper-containing materials such as scrap and
cement copper which contain little sulfur are processed by some
copper smelters, but not by others. This variation in sulfur
content could be significant on a day-to-day basis at a given smelter,
as well as among various smelters which handle differing quantities
of various feed materials. Apart from the difficulties in
developing an appropriate emission limitation, the monitoring
of a production-based limitation would be relatively complex.
One method of monitoring would necessitate, for example, measuring
the mass rate of flow of the emission stream, in addition to
the sulfur dioxide concentration, and measuring the production
of material.
After considering the above factors, the Administrator
has determined that the proposed sulfur dioxide emission limitations
should be specified as allowable concentrations of sulfur dioxide in gases
emitted from affected facilities. The performance of best demonstrated
7-41
-------
emission jontrol devices is directly related to the outlet
sulfur dioxide concentrations from the devices. The development
of percentage sulfur recovery emission limitations or production-
based emission limitations would have required a much more
extensive data base, and no increased effectiveness in controlling
sulfur dioxide emissions would have resulted. The proposed sulfur
dioxide emission limitations can be effectively monitored on a
continuous basis, whereas the monitoring of percentage sulfur
recovery or production-based limitations for smelters is generally
more complex and likely to be of unacceptable accuracy.
Sulfuric acid plants had been installed to recover or control
sulfur dioxide in strong effluent streams at several domestic
smelters prior to initiating development of the proposed standards.
These plants were all of single-absorption design. The operation
of these metallurgical sulfuric acid plants, as well as that of more
efficient double-absorption plants which were operating at several
foreign smelters, differs from that of conventional domestic
sulfur-burning acid plants because of the large fluctuations
in flow rate and sulfur dioxide concentration generated by some
smelting processes. Accordingly, the emission control performance
of metallurgical sulfuric acid plants could not be inferred directly
from the well-documented performance capabilities of conventional
domestic sulfuric acid plants. The establishment of sulfur dioxide
emission limits for metallurgical sulfuric acid plants thus required
that emission tests be conducted at smelting facilities.
7-42
-------
The Initial objective of the emission testing program was to
develop an appropriate sulfur dioxide emission limitation for single-
absorption acid plants, since no double-absorption plants were in
operation at domestic smelters. Three primary factors to be considered
in interpreting the data were identified:
1. Determination of the minimum averaging time which effectively
masks the large fluctuations in acid plant outlet sulfur
dioxide concentration. The control of copper converter
effluents was judged to be the most severe problem from
the viewpoint of concentration fluctuations.
2. Determination of a long-term effect of deterioration of acid
plant catalyst on outlet sulfur dioxide concentration.
3. Determination of the magnitude of time-averaged outlet
sulfur dioxide concentrations as compared with vendor
guarantees for short-term performance tests.
The sulfur dioxide emissions from a single-absorption sulfuric
acid plant (Kennecott Copper Corporation, Garfield, Utah, No. 7
acid plant) were continuously monitored by EPA for a period of
approximately ten weeks. The plant treated a portion of the effluent
discharged from nine copper converters. A detailed analysis of
a representative three-week period of data was performed, the
results of which are contained in Appendix III. The vendor
guarantee for the acid plant, constructed in 1970, is equivalent
to an outlet concentration of 2700 ppm sulfur dioxide. The computation
of time-averaged sulfur dioxide emission concentrations, for averaging
times of 4 to 12 hours, showed that an averaging period of at least
7-43
-------
six hours is necessary to substantially mask short-term high (>7000 ppm)
and low (<1000 ppm) sulfur dioxide emission concentration fluctuations,
and produce time-averaged emissions within the vendor guarantee.
The control efficiency of the No. 7 acid plant was judged not
to have been significantly influenced by catalyst deterioration
over the ten-week period of continuous monitoring. To estimate
the extent of degradation in acid plant performance between
periodic catalyst screenings, the results of the EPA emission
tests carried out on the No. 6 and No. 7 acid plants at the
same Kennecott smelter in June of 1972 were analyzed. At that time
the No. 7 acid plant was in the last month of operation before
catalyst screening, and the No. 6 acid plant was in the second
month of operation following catalyst screening. The emissions
from the No. 7 acid plant were 30% higher than those from the
No. 6 acid plant (see Appendix III). This increase is attributable
to catalyst deterioration and probably to a minor extent attributable
also to design and construction differences between the two acid
plants.
After the first domestic metallurgical double-absorption
sulfuric acid plant achieved routine operation, EPA began
continuous sulfur dioxide monitoring of the plant to develop
an appropriate sulfur dioxide emission limitation for double-
absorption sulfuric acid plants. The acid plant treated the
entire effluent from a three-converter aisle at the ASARCO
copper smelter in El Paso, Texas. Sulfur dioxide emissions from
7-44
-------
the acid plant were monitored for approximately seven months
from May until December 1973. The data from this test are
the primary basis for the proposed sulfur dioxide emission
limitations.
A detailed analysis of the ASARCO El Paso data is contained
in Appendix VI. The outlet sulfur dioxide concentration was averaged
over intervals extending from 15 minutes to 10 hours to determine
the minimum averaging time that masks large fluctuations. For
each of the several averaging times, percentages of the total
numbers of averages during the test period which exceeded selected
outlet concentration levels were calculated. The results showed
the expected trend that longer averaging times produce fewer
excursions above preselected outlet concentrations. Further,
irtost of the time-averaged outlet concentrations are considerably
less than the vendor guarantee of 500 ppm sulfur dioxide for the
acid plant. For example, only five percent of the averages exceed
250 ppm when averaging times of 5 hours or longer are used.
To determine an appropriate averaging time for copper smelter
emissions, the effect of averaging time on percentage of excursions
above the vendor guarantee of 500 ppm sulfur dioxide for typical
copper converter operations was examined. Since the inlet sulfur
dioxide concentrations for the ASARCO El Paso test were considerably
lower (3.8 percent average) than the 5 to 6 percent sulfur dioxide of
typical copper converter operations, the 500 ppm sulfur dioxide vendor
guarantee was adjusted to 400 ppm based on information collected
7-45
-------
during the test that related inlet and outlet sulfur dioxide
concentrations. The data show that the decrease in percentage
of excursions with increasing averaging time is relatively small
for averaging times longer than five to six hours. For example,
an increase in averaging time from 6 hours to 10 hours decreases
the percentage of averages exceeding 400 ppm sulfur dioxide
only slightly, from 1.20 percent to 0.55 percent. It is
concluded that a six-hour averaging time effectively masks
fluctuations in outlet sulfur dioxide concentrations from
copper converter operations, and the proposed sulfur dioxide
standard for copper smelters is based on this averaging period.
A six-hour averaging time is also predicted, as discussed above
in this section, from results of EPA continuous monitoring of a
single-absorption sulfuric acid plant that processes copper converter
gases.
The proposed sulfur dioxide standards for primary lead
smelters and primary zinc smelters specify a two-hour averaging ,
period, rather than a six-hour period as for copper smelters. The
shorter averaging time is based on judgments that normal lead
sintering machine and zinc roasting operations are inherently
more steady than copper converter operations. EPA analyzed
continuous records of sulfur dioxide concentrations produced by
two domestic lead sintering machine operations. The fluctuations
were not as severe as those observed from copper converter operations,
and the changes in gas flow rate are not expected to be as large
7-46
-------
as those encountered in normal copper converter operations.
Industry representatives have stated that sintering machines
are frequently shut down and restarted, thus precluding steady
operation of acid plants. However, it is not necessary to damp
possible excess emissions resulting from these shutdowns and
startups by increasing the averaging time for an emissions
limitation, because such excess emissions are excluded from
compliance testing under new source performance standards. Zinc
roasters which are subject to the proposed sulfur dioxide standard
discharge gas streams which are even more steady than lead sintering
machine effluents in sulfur dioxide concentration and flow rate.
Analysis of the ASARCO El Paso data shows that there was no
detectable catalyst deterioration during the monitoring period and, as
discussed above, that the inlet sulfur dioxide concentration was
considerably lower than would be realized from some other smelting
operations. To develop a sulfur dioxide emission limitation from these
data, it is therefore necessary to adjust the data to account for the
effects of catalyst deterioration and higher inlet sulfur dioxide
concentrations. The designer of the ASARCO acid plant indicated
that a 10 percent increase in sulfur dioxide emissions was expected
during the two-year period of operation between scheduled catalyst
screenings. The maximum sulfur dioxide inlet concentration which
can reasonably be expected to be generated by smelter processing
equipment with sufficient oxygen content for processing in an
7-47
-------
acid plant is 9 percent. A correlation between inlet and outlet
sulfur dioxide concentrations measured during the test showed that
an increase in inlet concentration from the average value for
the test, 3.8 percent sulfur dioxide, to a value of 9 percent
sulfur dioxide would produce an increased emission of approximately
200 ppm S02- Accordingly, the test data for six-hour averages
adjusted for catalyst deterioration and 9% sulfur dioxide inlet
concentration are shown in Table 7-1.
Table 7-1
FREQUENCY DISTRIBUTION OF ADJUSTED
OUTLET SULFUR DIOXIDE CONCENTRATIONS
(Averaging time - 6 hrs; Number of averages - 3876)
Outlet S02 (ppm)
Percentage of averages
exceeding outlet S02
400
20.0
450
10.0
500
5.00
550
2.45
600
1.75
650
1.20
700
0.90
750
0.45
The data of Table 7-1 show that no more than 10 percent of
the six-hour averages exceeds 450 ppm S02. While increases in
concentration above 450 ppm S02 initially produce substantial
decreases in the percentage of excursions above the increased
outlet concentrations, increases above 600 to 650 ppm S02 produce
only very small increments in the percentage excursions. On the
basis of the adjusted data of Table 7-1, a 650 ppm S02 emission
limitation would result in no more than 1.20 percent excursions.
It should be recognized, however, that the percentages of
excursions cited in Table 7-1 do not indicate directly the probabilities
of exceeding a specific emission limitation in a performance test under
7-48
-------
new source performance standards, since compliance Is determined
from the average of three runs. To estimate the reduced
probability of exceeding an emission concentration by averaging
three runs, all the six-hour averaged outlet concentrations exceeding
400 ppm S02 during the test (equivalent to 650 ppm S02 in Table 7-1)
were reviewed. Outlet concentrations during the period 24 hours
prior to, and 24 hours after, each excursion were used to compute
the maximum average of three runs during the 48-hour period.
The three six-hour averages were chosen so that none of the
periods overlapped. Of the 48 excursions recorded during the
entire test, only 6 resulted in excursions based on the average
of three runs. Therefore, the percentage excursion of 1.20 percent
cited for 650 ppm S02 in Table 7-1 would correspond to a much
smaller percentage rate of excursions during performance tests under
new source performance standards.
The proposed sulfur dioxide emission limitation is 650 ppm S02,
averaged over a six-hour period for copper smelters and over a two-
hour period for lead and zinc smelters. The EPA continuous monitoring
data from a double-absorption sulfuric acid plant show that this
limitation: (a) allows for a reasonable increase in emissions due
to acid plant catalyst deterioration, (b) accommodates the effects
of high inlet sulfur dioxide concentrations on outlet concentrations,
and (c) accounts for the effects of large fluctuations in acid plant
inlet and outlet sulfur dioxide concentrations. However, the EPA
7-49
-------
data also show that a 650 ppm S0;> limit will be exceeded a small percentage
of the time during normal operation, and that an increase in the
sulfur dioxide limit decreases this percentage of excursions.
The alternative of choosing a higher emission limit than 650 ppm
SOg was not chosen because: (a) substantial increases in the
limit would decrease the probable percentage of excursions
only slightly, and there is no certainty that a limit much larger
than 650 ppm S02 would not be exceeded on rare occasions, and (b) an
emission limit substantially in excess of 650 ppm SOo would not
reflect proper operation and maintenance of an acid plant during
most operating periods, since some 90 percent of the time the
plant could limit emissions to no more than 450 ppm S02-
Although the proposed standards are based on the application
of double-absorption acid plants to strong sulfur dioxide streams,
scrubbing systems and elemental sulfur plants with tail gas scrubbing
are technically capable of complying with the quantitative sulfur
dioxide limit (650 ppm) as discussed in Section 4.
7-50
-------
7.5.2.2 Particulate Matter
As discussed in Sections 4 and 5, fabric filters have commonly
been installed on blast furnaces and sintering machines within the
primary domestic lead smelting industry. Fabric filters have also
been installed on sintering machines in the domestic primary zinc
smelting industry and on one dryer in the domestic primary copper
smelting industry. To obtain data for the development of the proposed
standards for particulate matter, EPA conducted emission tests on
effluents from baghouses installed on the lead blast furnace at the
ASARCO lead smelter in Glover, Missouri, in July 1973, and on a
zinc sintering machine at the New Jersey Zinc Company smelter in
Palmerton, Pennsylvania, in February 1974. The latter test was
unsuccessful because an equipment malfunction allowed a portion of
the sintering machine gases to bypass the control equipment and enter
the stream being sampled for emissions. Extensive emission testing
to identify particulate matter emissions from primary copper, zinc
and lead smelters was not conducted because of the small number of
modern fabric filters in these industries which have suitable configurations
for testing.
As discussed in Section 4, the average concentration of three
runs of particulate emissions performed by EPA at the ASARCO lead
smelter in Glover, Missouri, was approximately 32 mg/dscm (0.014 gr/dscf).
The range of the three runs was 18 to 40 mg/dscm (0.008 to 0.017 gr/dscf).
The data from this test are summarized in Appendix VII. Other EPA test
data on particulate emissions from sources similar to primary lead and
7-51
-------
zinc smelters, such as secondary lead smelters and secondary brass
and bronze ingot production plants, are also discussed in Section 4
and summarized in Appendix VII. On the basis of these data, it is
concluded that a properly designed, operated, and maintained baghouse
can limit outlet particulate matter emissions from copper dryers,
zinc sintering machines, lead sintering machine discharge ends, lead
blast furnaces, and lead dross reverberatory furnaces to less than
50 mg/dscm (0.022 gr/dscf). The proposed standards for particulate
matter for copper, zinc and lead smelters reflect the use of control
devices equivalent to the baghouses tested, and limit particulate
matter emissions to 50 mg/dscm (0.022 gr/dscf).
7-52
-------
*
7.5.2.3 Opacity
The proposed standards include opacity limitations on effluents
from (a) copper dryers, (b) zinc sintering machines, lead blast furnaces,
lead dross reverberatory furnaces, and discharge ends of lead sintering
machines, and (c) sulfuric acid plants used to comply with the proposed
sulfur dioxide emission limitations.
A general discussion of the role of opacity standards under
section 111 of the Act is contained in the preamble to standards
* of performance for new stationary sources promulgated on March 8,
1974 (39 FR 9308). The proposed opacity standards are regulatory
requirements, as are the proposed sulfur dioxide and particulate
matter concentration standards. Enforcement of an opacity standard is
not contingent on first showing that a corresponding concentration
standard is being violated. Where opacity and concentration standards
are applicable to the same source, the opacity standard is not more
restrictive than the concentration standard. The concentration standard
is established at a level which will result in the design, installation,
and operation of the best adequately demonstrated system of emission
reduction (taking costs into account) for each source. The opacity
standard is established at a level which will require proper operation
and maintenance of such control systems on a day-to-day basis, but
not require the design and installation of a control system more
efficient or expensive than that required by the concentration standard.
Within the proposed opacity standards, there are specified
periods during which the opacity standards do not apply. Time
7-53
-------
exemptions further reflect the stated purpose of opacity standards
by providing relief from such standards during periods when
acceptable systems of emission reduction are judged to be
incapable of meeting prescribed opacity limits. Opacity standards
do not apply to emissions during periods of startup, shutdown,
and malfunction (38 FR 28564), nor do opacity standards apply
during periods judged necessary to permit the observed excess
emissions caused by, for example, bag shaking and unstable process
conditions. Time exemptions provide for circumstances specific
to individual source categories and, coupled with the startup-
shutdown-malfunction provisions and higher-than-observed opacity
limits, provide assurance that opacity standards are not unfairly
stringent.
As discussed above in this chapter, the proposed standards
for particulate matter generated by copper dryers, by sintering machines,
and by lead blast furnaces, dross reverberatory furnaces, and
sintering machine discharge ends are based upon the application
of fabric filters to these sources. As discussed in Section 4
and summarized in Appendix VIII, EPA-observations of the opacity
of the effluents from the baghouse operating on the ASARCO lead
blast furnace at El Paso, Texas, were of more than 10 percent opacity
for a total time of only some 8 minutes during one test of approxi-
mately 14 hours duration. The observations of periodic visible emissions
were as high as 35 percent opacity. However, the opacities averaged
for two observers exceeded 20 percent for an average of only
5 seconds per hour during the entire test period with a maximum
of 30 seconds per hour. In another set of observations of the opacity
7-54
-------
of the effluents from the same baghouse, visible emissions were
observed during a greater percentage of the observation time.
The periods of highest opacity, during which up to 40 percent
opacity was observed, were correlated with the shaking of bags.
The opacities averaged for two observers were greater than
20 percent for slightly less than 4 minutes and 2 minutes during,
respectively, the first and second hours of observation. On the basis
of these data, it is the Administrator's judgment that baghouses
applied to the primary copper, zinc or lead smelter particulate emission
streams can be properly designed, maintained, and operated such that:
1. The opacity is limited to less than 20 percent
except for periods associated with bag shaking, and
2. A time exemption of two minutes per hour is
adequate to accommodate periods of higher opacity
associated with bag shaking.
The purpose of the proposed opacity standards for sulfuric
acid plants used as control devices to comply with the sulfur dioxide
standards is to ensure: (a) that the acid plant is properly main-
tained and operated to minimize $03 emissions which would be
converted into sulfuric acid mist in the atmosphere, and
(b) that a high-efficiency mist eliminator is installed,
maintained, and operated to collect sulfuric acid mist within
the acid plant stack. As discussed in Section 4, well-designed
and operated sulfuric acid absorbing towers incorporating high-
efficiency mist eliminators are capable of restricting sulfuric
7-55
-------
acid mist emissions from sulfuric: acid plants to low-opacity wisps.
Acid plant and mist eliminator manufacturers have stated that the
emissions from sulfuric acid plants equipped with high-efficiency
mist eliminators are normally of less than 10 percent opacity.
To obtain additional data on the opacity of the effluent from
a metallurgical double-absorption sulfuric acid plant, EPA
observed emissions at the ASARCO copper smelter in El Paso,
Texas. The data are summarized in Appendix VIII. During
approximately 10 hours of simultaneous observations by two
observers over a period of two days, visible emissions were detected
during only a single 5-6 minute period. However^ the opacity
exceeded 10% for 2.5-5.5 minutes and 20% for 1.75-2.5 minutes
as determined by the two observers, and reached as high as 35% opacity.
EPA continuously monitored inlet sulfur dioxide concentration and
outlet sulfur dioxide concentration of the acid plant, as well as
monitoring other acid plant and process parameters, during the
observation of acid plant opacity. An analysis of these data did not
indicate that a malfunction had occurred, and the short, isolated period
of visible emissions was concluded to be a part of normal metallurgical
acid plant operation. Accordingly, a time exemption for periods of
higher than normal opacity is justified. On the basis of the above
data and information, it is the Administrator's judgment that a properly
designed, maintained, and operated metallurgical double-absorption
sulfuric acid plant equipped with a high-efficiency mist eliminator
4
*
7-56
-------
can limit visible emissions to no more than 20% opacity, except
for two minutes in any one hour.
7-57
-------
REFERENCES FOR SECTION 7.
1. "Air Quality Criteria for Sulfur Oxides," U.S. Dept. of
Health, Education, and Welfare, Public Health Service, NAPCA
Publication No. AP-50, 1970.
2. "Air Quality Criteria for Particulate Matter," U.S. Dept. of
Health, Education, and Welfare, Public Health Service, NAPCA
Publication No. AP-49, 1969.
7-58
-------
8. ENVIRONMENTAL EFFECTS
8.1 SECONDARY POLLUTION
For the purposes of this investigation, secondary pollution is
meant to include land pollution and water pollution. Various forms
of water pollution, as discussed in the text, are characterized
below:
1. Dissolved solids (or total dissolved solids) - These are
theoretically the anhydrous residues of dissolved constituents
contained in the water. Dissolved solids can be detrimental
to fresh water since, as the concentration increases, fresh
water will become more saline. Water quality factors
such as taste and color will be affected.
2. Chemical oxygen demand (C.O.D.) - This is a measure of the
oxygen-consuming capacity of organic and inorganic matter
present in water on waste water. As C.O.D. increases,
water quality decreases because of the decreased dissolved
oxygen content available for support of aquatic life.
3. Hardness of water - This is a characteristic of water
imparted by salts of calcium, magnesium, and iron, such
as bicarbonates, carbonates, sulfates, chlorides, and
nitrates, that causes the curdling of soap, increased
consumption of soap, deposition of scale in boilers,
damage in some industrial processes, and sometimes objectionable
tastes.
4. Soluble magnesium salts (epsom salts) - This is a constituent
of dissolved solids. Magnesium is considered relatively
8-1
-------
non-toxic to man and not a public health hazard because,
before toxic concentrations are reached in water, the taste
becomes quite unpleasant. At high concentrations, magnesium
salts have a laxative effect, particularly upon new users,
although the human body can develop a tolerance to magnesium
over a period of time.
Land pollution, as discussed in this text, refers to the disposal
of the solid waste created by the neutralization of abatement-derived
sulfuric acid.
For the primary nonferrous smelting industry, two distinct
potential sources of secondary pollution can be identified. The
first type results from the application of sulfuric acid plants to
strong sulfur dioxide smelter off-gases if the sulfuric acid
cannot be marketed and must be neutralized. The other type is
associated with the application of scrubbing techniques to weak
gas streams. It is anticipated that the production and possible
disposal of elemental sulfur and liquid S02 will not produce
secondary pollution if adequate safeguards are taken.
There are numerous prospective uses for sulfuric acid, including
various uses in the chemical industry, particularly for acidulating
phosphate rock to produce phosphate fertilizer; the leaching of
copper oxide ores and low-grade copper sulfide/copper oxide ores;
and leaching of uranium ores to process the uranium into a concentrated
form. All domestic primary nonferrous smelters are marketing their
current production of sulfuric acid or using it internally. While
excessive costs of shipping to outlets may preclude the marketing
8-2
-------
of some sulfuric acid from new acid production capacity at smelters,
the strength of the present acid market indicates that most of
the acid can be sold.
Neutralization of abatement-derived sulfuric acid by the "wet"
process may produce both land pollution and water pollution if a
marketable application for the neutralized acid sludge (gypsum)
cannot be found. Ponding has been a technique favored by a number
of industries for waste disposal, and it is anticipated that smelters
which cannot dispose of neutralized acid will employ the same
technique. Water pollutants from ponds are typically introduced
into underground and surface water supplies through seepage from
cracks in the base of the pond and from pond overflow, respectively.
The possible forms of water pollution include dissolved solids,
chemical oxygen demand, soluble magnesium salts (epsom salts) and
increased water hardness.
Procedures and techniques are available which will prevent
the water pollution problems of neutralization and subsequent
ponding from occurring:
1. Proper site selection and location of waste disposal
ponds.
2. The use of impermeable pond liners.
3. Closed-loop operation of ponds to prevent pond liquor
overflow.
The concerns expressed about potential water pollution problems
from the point of view of the magnitude of the soluble contaminants
8-3
-------
in the gypsum sludge do appear justified, however, when adequate
safeguards are not taken.
The "dry" sulfuric acid neutralization process shows promise
for producing minimal secondary pollution problems. One domestic
primary copper producer has stated that a method of neutralization
has been developed which results in the production of a hard-crust,
dry gypsum product. This product, as illustrated by a pilot study,
will not produce water pollution.
The purge or spent scrubber solutions from the ammonia-based,
sodium-based, dimethyl aniline, and calcium-based scrubbing systems,
if directly discharged to a local water course, could produce
water pollution. The possible forms of water pollution include
chemical oxygen demand, dissolved solids, increased organic
content, soluble epsom salt content, and increased water hardness.
Methods to solve the problems of water pollution are available and
have been demonstrated for both the ammonia and sodium-based
scrubbing systems. Practical disposal methods for the dimethylaniHne
purge are also available. Closed-loop effluents or water treatment
facilities will, in most situations, be required for the spent
calcium-based scrubber solution; solid waste pollution is a possible
result of this scrubbing technique.
In conclusion, several types of possible secondary pollution
derived from air pollution control have been identified. Methods
to minimize these problems have been demonstrated or are being
developed.
8-4
-------
8.1.1 Neutralization of Sulfuric Acid
The amount of sulfur-containing materials which must be
marketed or discarded varies directly with the degree of S02
control attained by a smelter. Strong SOg gas streams are currently
controlled on the basis of marketability. In the past, sulfuric
acid or liquid SOg plants have been constructed and operated
to produce sulfuric acid or liquid S02 in sufficient quantities
for sale or internal consumption. Of the 28 existing domestic
primary copper, zinc, and lead smelters, nineteen smelters produce
sulfuric acid and one smelter produces liquid SC^. These two
commodities have been the only sulfur-containing materials produced
in the United States from smelter off-gases. Future control plans,
as envisioned by these existing facilities to ensure compliance
with local and national ambient air quality standards, were presented
in Section 5. These plans include the construction of additional
sulfuric acid and liquid S02 plants. One new smelter, the construction
of which has just been announced, plans to produce elemental sulfur
from smelter off-gases. Thus, in all probability, much of the
sulfur which enters a nonferrous smelter as a constituent of the
concentrate will be recovered from smelter off-gases through
the utilization of an elemental sulfur plant, a liquid S0£ plant,
or a sulfuric acid plant.
Table 8-1 tabulates S02 recovery statistics for the existing
domestic lead, zinc, and copper industries:
8-5
-------
Table 8-1. SULFUR OXIDE GENERATION AND RECOVERY
AT U.S. SMELTERS (1969-1972)
Equiv.
Concentrate Sulfur S02 S0? Overall H2S04
Type
Smelter
Copper
Zinc
Lead
Processed
(T/D)
18,970
3,405
2,950
Content
(T/D)
6,070
1,022
525
Generated
(T/D)
11,900
1,940
980
Controfled SO? Prod.
(T/D) Control (*) (T/D)
3,700
1,322
260
31
68
27
5,660
2,000
400
Thus, an approximate total of 8,060 tons per day of sulfuric add
are currently being produced and consumed by either internal usage
or the domestic market. Magnitudes of the specific applications of
this metallurgically produced sulfuric acid are not known. The
primary application of this sulfuric acid"is for the production of
fertilizer. Some acid is used as a leaching medium for oxide ores.
Zinc smelters in the northeast section of the United States supply
acid to steel mills for steel pickling. Several smelters utilize
their by-product sulfuric acid internally as makeup for electrolytic
processes, while other smelters employ large chemical companies
which, in turn, market the acid.
Cost data received from several smelters that operate metal-
lurgical sulfuric acid plants indicate that, on the average, the
product acid is currently being sold at a net loss. Of the reporting
smelters, the zinc and copper facilities indicated a net profit,
8-6
-------
whereas the reporting lead smelters stipulated a net loss in acid
sales. Since cost data were not received from all metallurgical
acid-producing facilities, the profit and loss averages computed for
the nonferrous industry do not supply a complete picture of sulfuric
acid profitability.
New S02 control schemes planned by the domestic copper industry
should increase sulfuric acid production considerably. SCL abatement
plans made by the existing zinc and lead smelters should not increase
acid production very much beyond the values shown in Table 8-1.
Recent pronouncements by industry about the requirements of
sulfur compounds such as sulfuric acid and liquid SOp have indicated
that the once-predicted glut of sulfur on the market may not appear.
Indeed, over and above the sulfuric acid used internally by the
smelting industry, there are indications that any additional sulfur
derived from pollution abatement may fill a potential sulfur
deficiency in certain geographical areas of the country which
are not within reasonable distances of commercial sulfur and
sulfuric acid producers. Thus, future sulfur market conditions
may make S02 abatement programs more attractive and possibly
profitable.
There is no doubt that an analysis of the disposition of sulfuric
acid produced from smelter effluents is extremely complex. However,
some predictions regarding the potential for acid neutralization
can be made:
8-7
-------
1. New copper smelters will most likely employ process
technology which will allow the production of either
elemental sulfur or sulfuric acid. This generalization has
already been evidenced by the announced construction of the
new Phelps Dodge copper smelter at Tyrone, N. M., which will
produce elemental sulfur from flash smelter off-gases and
sulfuric acid from the converter off-gases. The modification
of existing copper smelting facilities may possibly necessi-
tate some neutralization since smelter operators, indicate
that at present their acid markets are already saturated.
However, rather than leading to the neutralization of
substantial quantities of sulfuric acid, this may stimulate
more widespread leaching of copper oxide ores within the
industry. This would serve as an internal outlet for
sulfuric acid.
2, New zinc smelters are not likely to neutralize sulfuric
acid. All currently operating domestic zinc smelters are
of the custom type. Each physical plant location has been
determined from an appraisal of several factors, such as
access to raw materials (natural gas, concentrates,
inexpensive electricity, etc.) and proximity of product
markets (i.e., zinc, zinc oxide, cadmium, and sulfuric
acid). All acid-producing zinc smelters will either be of
the vertical retort type or the electrolytic type and not
of the horizontal retort type. New zinc smelters should be
physically located near sufficient acid markets and,
8-8
-------
therefore, positive acid cost margins will prevail and it
is predicted that neutralization will not be necessary.
3. New lead smelters will in all likelihood produce sulfuric
acid and sell this acid at a net loss due in part to their
geographical location in relationship to potential acid
markets. Three of the six existing lead smelters operate
acid plants and have each reported a net loss of acid sales
to date. Since two lead smelters have been built since
1968, the demand for future lead smelting capacity in the
near future is predicted to be low. Future technology may
allow the production of elemental sulfur from sinter machine
off-gases, after such an effluent has been concentrated.
In weighing the pros and cons of acid neutralization, one of the
most important of all criteria, therefore, will be the economics of
the sulfur and sulfuric acid market.
For the purposes of this discussion, an assumption is made that
all elemental sulfur which would be produced but not marketed could
be safely stored in block form in the vicinity of the smelter.
Shelter could be provided so that fugitive dusting and wash-off
would not occur.
The primary method for disposal of abatement-derived sulfuric
acid is by neutralization with limestone. The chemical steps
involved in the production and neutralization of smelter sulfuric
acid follow:
8-9
-------
1. Sulfur enters the metal-production scheme principally as
a sulfide of zinc, lead, copper, and iron (i.e., ZnS, PbS,
CugS, and CuFeS2).
2. The input sulfur is converted to sulfur dioxide, which is
then contained in the smelter off-gases:
a. Zinc roasting
2ZnS + 302 -> 2ZnO + 2S02
b. Lead sintering
2PbS + 302 -*• 2PbO + 2S02
c. Overall copper recovery equations
Cu2S + 02 + 2Cu + S02
2CuFeS2 + 502 •»• 2Cu + 2FeO + 4S02
3. Sulfur dioxide contained in the smelter off-gases is
converted to sulfuric acid:
2S02 + 02 -> 2S03
S03 + H20 -»• H2S04
4. Sulfuric acid is neutralized with limestone:
H2S04 + CaC03 -»• CaS04 + C02 + H20 + other salts
Orf a stoichiometric basis, one mole of limestone would be required
to neutralize one mole of sulfuric: acid; and, in turn, one mole of
CaSO. would be produced. Besides the chemical production of CaSO,,
^
other salts such as CaS03 and MgSC<4 are formed. The MgSO,, which
is formed when MgSO^, generally a minor constituent of limestone,
reacts with sulfuric acid.
Of primary importance in the discussion of secondary pollution
is the CaS04/CaS03 and MgS04 produced from various air pollution
8-10
-------
control schemes. Since CaS04/CaS03 would be produced in large
volumes as a sludge, it could produce solid waste problems if
it were not marketed.
Disposal of solid waste by ponding has historically been
a favorite technique in a number of industries. It is anti-
cipated that ponding will be employed at most copper smelters
which produce sulfuric acid and then neutralize this acid with
limestone. The technology of pond construction and pond operation
is well demonstrated. Frequently, however, waste disposal ponds
are constructed and operated with less than adequate attention
paid to potential water pollution effects. This is particularly
true concerning the seepage of pond liquor into underground water
supplies and overflow of pond liquor into surface water. Vertical
and especially lateral movement of ground water can be as slow
as a meter per year. As a result, it might take many years
before the seepage of pond liquor into an underground water supply
would be discovered by a consumer of underground water downstream
from a waste disposal pond site.
Contamination of underground water supplies can be prevented,
however, through the use of pond linings in the construction of
waste disposal ponds. This normally ensures that the pond is
impermeable to pond liquor and prevents seepage of pond liquor
into underground water supplies. Generally, synthetic pond linings,
such as polyvinyl chloride, polyethylene, polypropylene, synthetic
8-11
-------
rubbers and nylons, are considered superior to natural linings
composed of clay, concrete, or wood.
Contamination of surface water can be prevented by operation
of waste disposal ponds with no overflow discharges of pond liquor.
Closed-loop operation of a waste disposal pond permits a water
balance to be maintained between the disposal pond and the
limestone neutralization operation.
Winds and rainfall can also lead to contamination of surface
water if the rain is permitted to run off filled waste disposal
ponds which are no longer in operation. Such ponds must be
protected both to prevent dusting of dried residue and to prevent
the rainwater runoff from leaching soluble contaminants from the gypsum
sludge. This can be accomplished through use of synthetic covers
similar to pond liners, or through the use of various chemical
treatments which form a hard, impermeable crust on the surface
of the gypsum sludge.
With an awareness of the economics of acid neutralization,
as well as the possibility of producing secondary pollution, one
domestic primary copper smelting company has developed a dry
limestone neutralization process.^ The product of this method,
demonstrated by means of a pilot plant study, is a solid.
Approximately two to three tons of this solid neutralization
product, which is a combination of gypsum and unreacted limestone,
are formed for each ton of neutralized sulfuric acid. After this
product is discharged to a disposal area, a hard crust forms over the
material; this crust minimizes secondary pollution problems
8-12
-------
such as dusting and rainwater runoff of contained soluble materials.
Because of the high content of unreacted limestone found in the
solid neutralization product, a market has not yet been found.
The American Smelting and Refining Company,3 after performing
a laboratory-scale limestone neutralization study, stated that even
with a low percentage conversion of magnesium to the soluble sulfate
(salt) form, a large amount of soluble material would be put out
on a dump subject to rainfall. This study also attempted to
define the neutralization technique, as well as the fineness
of the limestone grind, which should be employed for optimal results.
Two types of limestone were used, one taken from the Hayden,
Arizona, area and the second from Montana. These two limestones
represented, respectively, the low and high content values of magnesium,
reported as 0.9% and 3.3% MgO. Two different neutralizing techniques
were employed, a wet method and a dry method. With both techniques,
the fineness of the limestone grind was determined to be the major
parameter for providing the potential magnitude of secondary pollution.
It was determined that the finer the grind, the smaller the amount of
limestone required for neutralization, but the greater the solubilization
of total magnesium. Magnesium solubilization was found to vary from
approximately 40 to 80 percent of the total magnesium, depending upon
the grind of the limestone used for neutralization. On an absolute
scale, the greater weight of limestone required for the coarser
grind produced a greater magnitude of solubilized magnesium. Based upon
this laboratory investigation, an optimal grind produced a limestone
requirement of 129 percent of stoichiometric.4 The fine grind value,
8-13
-------
which would be used in actual practice, could only be determined by
means of both an economic and a pilot-plant study.
The disposal of potential gypsum sludge at a smelter, however,
is not likely to present an unmanageable solid waste disposal
problem in terms of the quantity of material to be handled; smelters
currently manage large waste disposal operations for slag wastes.
Though the expected waste disposal program will be large, other
industries, such as the phosphoric acid industry in Florida, currently
manage waste disposal operations of the same general order of
magnitude as would be expected from a smelter. The following example
illustrates quantities of potential solid and liquid wastes produced
by acid neutralization by the wet process:
A primary copper smelter utilizes a conventional roaster-reverberatory
furnace-converter pyrometallurgical process. The copper concentrate,
containing 32 percent sulfur, is consumed at a rate of 1000 tons per day.
Three percent of the input sulfur is discharged in slag, while the
remaining 97 percent is converted to sulfur dioxide (34 percent from
the roasters, 19 percent from the reverberatory furnaces, and the
remaining 44 percent from the converters). S02 emissions from the
roasters and converters are controlled by one double-absorplion sulfuric
acid plant. All produced acid is neutralized with 150 percent stoichiometrlc
limestone containing CaC03 and MgCOa analyzed at 48.2 percent CaO and
3.3% MgO, respectively. If the acid plant operates at a conversion
efficiency of 99.5 percent, an average of 760 tons per day of acid
is produced. This quantity of sulfuric acid contains approximately
8-14
-------
•*
78 percent of the smelter's input sulfur. Approximately 1340 tons
per day of limestone would be required for this neutralization. CaS04,
CaS03, MgS04 and partially reacted limestone would account for 1510 tons
per day of by-product sludge material. Of most importance is that
nearly 135 tons of MgS04 could be produced during each operating day.
This model copper smelter would normally produce approximately 700
tons per day of waste material (i.e., slag). Thus, with sulfuric
acid neutralization, this smelter must dispose of an additional
* 215 percent solid waste.
As a comparison to the above illustration, a copper smelter of
equal capacity employs process technology which produces strong S02
off-gases only. Sulfuric acid is produced from all of these off-gases
and is subsequently neutralized by the method used in the preceding
example. About 96.5 percent, of the smelter's input sulfur will be contained
in 945 tons per day of sulfuric acid. Approximately 1680 tons per day
of limestone, having the same constituent values as the limestone
previously used, would be required for 150 percent stoichiometric
neutralization. Nearly 1860 tons per day of by-product solid material
would be formed and as much as 166 tons per day of MgSO/^ could be produced.
Neutralization, in reality, should not produce the high magnitude
of potential solid and liquid pollution indicated by the above two
examples. Limestone requirements of less than 150 percent stoichiometric
may be realized for some neutralization programs.^ The value of 3.3
percent MgO used in the above illustrations is high when compared to
other limestones, such as that found in Hayden, Arizona. The form that
8-15
-------
the magnesium could take in the neutralization product is also
questionable. Solubilization does occur to some extent, as indicated
by the American Smelting and Refining Company's investigation.
Formations of sulfites and oxides of magnesium, as well as unreacted
MgC03, are possible.
Though there are potential problems with the neutralization
of sulfuric acid by the wet process, solutions to those problems
are available. The most desirable solution to all of the
potential problems would be the consumption of the by-product
gypsum in the manufacture of wall board or other gypsum products.
At present this outlet has not materialized; however, future markets
for gypsum are possible.
A major problem which might be encountered in the neutralization
of acid is the formation of soluble magnesium salts resulting in
the degradation of surface and underground water supplies. Water
quality will not be degraded by soluble magnesium salts if a closed-
loop operation is employed. If an open-loop system is used, the
extent to which supernatant water is recycled within the operation
would be dependent upon the characteristics of the process wastes,
the quantity of the waste discharge, and the magnitude of the receiving
streamJ The disposal area can be designed so that ground water
seepage of supernatant runoff is prevented. Soluble magnesium salts
contained in the settling pond can also be precipitated. The addition
of lime to a purge stream taken from the settling pond could maintain
the pond's concentration of soluble magnesium salts at a constant level.
The magnesium salts contained in this purge would be converted to
insoluble magnesium hydroxide which would later settle to the bottom
of the pond.
8-16
-------
In conclusion, neutralization of abatement-derived sulfuric acid
by the "wet" process may produce both land pollution and water pollution.
Land pollution could occur as a result of the disposal of large
quantities of calcium sulfate and calcium sulfite sludge produced
during neutralization. Water pollution in the forms of chemical
oxygen demand, dissolved solids, soluble magnesium (epsom) salt
content, and increased water hardness could also be a result of
neutralization by the "wet" process. Employing large, closed-loop
settling ponds lined with minimum-permeability materials should
provide maximum assurance that water pollution will be negligible.
Precipitating soluble magnesium salts by the addition of lime could
also minimize this potential water pollution source.
Minimum secondary pollution should arise by the usage of the
"dry" acid neutralization technique.
8.1.2 Scrubbing Systems
Ammonia Scrubbing Systems—
The ammonia scrubber has been applied to off-gases of a lead sinter
machine, a zinc roaster, and several sulfuric acid plants.
Basically, the process effluent containing S02 enters a scrubber
which employs an ammonia solution as the scrubber media. This media
chemically absorbs the S02 and the reaction products (sulfites,
bisulfites, and sulfates of ammonia) are discharged as a solution at
the scrubber outlet. If this salt solution were released directly
to a ground water supply without prior oxidation, a chemical oxygen
demand (C.O.D.) could produce an anaerobic effect on the water course.
Even if the ammonium solution were completely oxidized to ammonium
8-17
-------
sulfate prior to release, the ammonium ion has the potential of extracting
oxygen from the water course. Since these ammonium salts are soluble,
their addition to a water course would also increase the total dissolved
solids of that course. Thus, it is extremely important from the
standpoint of secondary pollution that numerous options exist for the
conversion to other final scrubber products.
One proven technique involves acidifying the ammonia sulfite-bisulfite
scrubber solution with concentrated sulfuric acid. Two products will be
formed, a strong S02 gas stream and ammonium sulfate. The governing
chemical equations are:
2NH4HS03 + H2S04 -> (NH4)2 S04 •>• 2S02 + 2H20
(NH4) S03 + H2S04 -> (NH4)2 S04 + S02 + H20
The S02 can be used for the production of sulfuric acid, liquid S02, or
elemental sulfur. In some sections of the U. S., ammonium sulfate is
a saleable fertilizer. If a limited market exists for ammonium sulfate,
other ammonium salts can be produced by employing other concentrated
acids in lieu of H2SO,. Namely, ammonium nitrate or ammonium phosphate
can be produced by using nitric or phosphoric acid, respectively. Thus,
if a fertilizer market does exist and the required type of acid is
available in quantities necessary for the salt production, secondary
pollution from this type of operation will be minimal.
To illustrate the quantities of materials involved with this
scrubbing technique, the following example is presented. A primary
lead smelter employs an updraft sinter machine with a split effluent.
While sintering, 85 percent of the input sulfur to the sinter machine
is oxidized to S02; 75 percent of this S02 is drawn off from the front
8-18
-------
f
»
of the machine as a 6 percent 862 effluent, which is then converted
to H2S04 in a double-contact sulfun'c acid plant. Tail-gas concentrations
average 500 ppm SO^. The remaining 25 percent of the generated S02
is removed from the rear section of the sinter machine as 0.5 percent
S02 off-gas. This effluent, 80,000 scfm, is subjected to particulate
control by means of a baghouse. The outlet particulate grain loading
averages under 0.02 gr/scf. The entire weak effluent is then passed
through an ammonia scrubber where 90 percent of the S02 is removed by
the scrubber liquor. The outlet S02 concentration from the scrubber
averages 500 ppm S02. or an equivalent mass emission rate of approximately
5 tons/day S02. The remaining 45 tons/day :>u2 are chemically contained
in the ammonia sulfite-bisulfite slurry. The scrubber has been designed
to produce a bisulfite-to-sulfite weight ratio of 5 to 1. On a 100
to acidify 72 tons per day of ammonia sulfite and bisulfite lu and
60 tons/day, respectively); 55 tons/day of ammonium sulfate is produced.
A strong S02 gas stream, which contains about 45 tons/day S02, is also
generated during acidification. This effluent is combined with the sinter
machine strong off-gases, and the combination is treated by the double-
contact sulfuric acid plant. If the ammonium sulfate and the additional
30 tons/day of sulfuric acid produced from the S02 released by the acidi-
fication of the ammonia sulfite/bisulfite solution can be marketed, there
will be no secondary pollution. If the marketability of these two products
is limited, HNO, or H3PO, can be used for the acidification step, and
ammonium nitrate or ammonium phosphate, both with a concentrated S02 gas
stream, will be the resultant products.
8-19
-------
One U. S. sulfuric acid manufacturer employs this type scrubber for
S02 tail gas control.5 The initial plan was to produce marketable ammonium
sulfate and S02 as scrubber products. After a production problem occurred
which had nothing to do with the chemistry of ammonia scrubbing, the plant
decided to incinerate the scrubber slurry. Upon burning this sulfite-
bisulfite slurry in the plant's combustion chambers, the resulting S02»
N2, and water vapor combustion products returned to the sulfuric acid
plant. The only economic loss derived from this burning process was
the consumption of ammonia. There were no incidences of secondary *
pollution reported by this plant.
An ammonia scrubbing system is used at one other U. S. sulfuric
acid-elemental sulfur facility." Until recently, the ammonium sulfite-
bisulfite-sulfate liquor was acidified with sulfuric acid, with the product
20 tons/day of ammonium sulfate marketed as fertilizer and the concen-
trated S02 effluent returned to the acid facility. Because of the limited
market for ammonium sulfate, this plant currently transports its
ammonium sulfate solution approximately 50 miles to a fertilizer plant
where it is used in the manufacture of complex fertilizers.
Both acid producing facilities; discussed above reported the
formation of a large ammonium sulfate cloud (blue mist) during
scrubbing. Both manufacturers remedied this secondary pollution
problem by the installation of mist eliminators.5*6 "*
Other techniques have been applied which either produce ammonia
-i t
for recycle or allow materials to be made for marketing. Ammonium
bisulfite has been found to be an effective additive to sulfuric acid
leaching solutions, since it reduces the cost of metallic iron used as ^
8-20
-------
4
the precipitant.8 Finally, the double alkali scheme, which would
produce calcium sulfate as the solid waste material and ammonium hydroxide
as the return solution to the ammonia scrubber, may soon be available for
SCL control .
In summation, the salt solution produced by the ammonia scrubbing
technique could produce secondary pollution; however, there are numerous
methods available for the production of saleable by-products or safe
disposal methods.
» Sodium Sulfite-Bisulfite Scrubbing—
This system has not yet been applied to the off-gases of a primary
lead, zinc, or copper smelter.
The scrubber medium for the system is a sodium sulfite-bisulfite-
water solution. The SOa contained in the gas stream being scrubbed
> chemically reacts with this solution, and the final scrubbing
solution is a sodium sulfite-bisulfite-sul fate-water mixture.
Since the sodium sulfate contained in this mixture cannot chemically
aid the scrubbing process, the sulfate content must be held constant
if the scrubber effluent is to be recirculated; thus, the need for a
purge stream. Generally, the sodium scrubber purge stream contains 4.5
to 5.5 percent sodium sulfate. The magnitude of this stream is dependent to
some extent upon the afflounc of oxygen contained in the scrubbed off-gases
since this oxygen will drive more sulfite and bisulfite to sulfate.
If this purge stream were discharged directly to a water course,
water pollution, in the forms of chemical oxygen demand and dissolved
solids, could occur. 9
One method which can be used to partially reduce the potential
water pollution problems derived from the direct discharge of the
8-21
-------
sodium-based scrubber purge is to convert most of the effluent's
sodium sulfite content to sodium sulfate. This conversion is possible
by the addition of sulfuric acid, or in chemical form:
Na2S03 + H2S04 -> Na2S04 + H20 + S02
2NaHS03 + H2S04 -> Na2S04 + 2H20 + 2S02 .
Most of the S02 will emerge as a strong S02 gas stream. The resulting
solution, containing dissolved sodium sulfate and a very small amount
of sodium sulfite, will have a pH of about 1 or 2. After caustic is
added and the pH is raised to about 7, the final solution can be
discharged to a water course if the quantity of discharge does not
O in
present a dissolved solids water pollution problem. ' Two domestic
regenerative sulfuric acid facilities are using this method. Prior
to scrubbing, the gas streams at both facilities contain about 4500 ppm
S02 and 8 percent oxygen, and have gas volumes of nearly 70,000 scfm. Each
final discharge stream contains approximately 20,000 pounds per day
sodium sulfate (reported as sulfate) and 100 pounds per day sodium
sulfite (reported as sulfite). The equivalent effluent flow rate from
each site is nearly 8 gallons per mi'nute, part of which is water
dilution which ensures the retention of sodium sulfate in solution
while processing.
In some instances of S02 control by the usage of sodium-based
scrubbing systems, the discharge of the scrubber purge to a water
course, even after acidification, could produce dissolved solids
water pollution. Various techniques to remedy this potential pollution
problem are currently being formulated and evaluated by vendors
and current, as well as potential, users of this scrubbing system.
8-22
-------
The sodium-based double-alkali scrubbing process is one of these
techniques. This technique involves the removal of S02 from a
process off-gas by means of the sodium scrubbing method. The purge
solution, composed of sulfites, bisulfites, and sulfates of sodium,
is then treated with lime or limestone to remove, as a precipitate,
solid calcium sulfites and sulfates and to regenerate sodium hydroxide
and sodium sulfite in solution. Thus, an essentially insoluble solid
product will be formed and can be disposed of as a solid waste, and a
liquid effluent can be returned to the scrubber for reuse. No
secondary water pollution problems should occur.
An existing domestic zinc smelter is currently evaluating the
19
applicability of various S02 scrubbing systems to its process effluents.
When theoretically applying a sodium-based system to the acid plant tail
gas and sinter machine effluent, potential water pollution problems
derived from the scrubber purge stream were realized. Since the oxygen
content of the sinter machine off-gases is nearly that of ambient air,
an assumption was made by the company that a greater than 90 percent
oxidation rate of sodium sulfite to sulfate could occur. This high rate
would produce a "once through" system with a very large sodium
salt solution disposal problem. When applying the sodium system to
the acid plant tail gas containing approximately 6 percent
oxygen and having a flow rate of about 80,000 scfm, a purge
stream of 35 gallons/minute containing nearly 21 pounds/minute
of sodium sulfate was calculated. Since local restrictions will
not allow the release of this quantity of purge to the local water
course, company engineers are attempting to remedy this potential
disposal problem by development of a suitable disposal system.
8-23
-------
A recently designed system, which is currently being evaluated
at the bench level, employs the following approach. The entire
purge stream is first sent to a holding tank. The purge then proceeds
to a thickener, where a lime solution is blended. The underflow
from this thickener is then sent to a gasifier where pure S02
is added. This causes all of the calcium to be in solution as
calcium bisulfite. The solution is then stripped, and the calcium
precipitates out as a sulfate while the sodium remains in solution
as a bisulfite. This stripping reaction is shown below:
Na2S04 + Ca(HS03)2 •* CaS04(i) + 2NaHS03
The calcium sulfate can be disposed of as a solid and the sodium
bisulfite solution can be recycled to the scrubber absorber. The
company states that there are no "iquid discharges from this closed-
loop operation. This system can be considered a form of double-
alkali scrubbing.
One application of a sodium-leased scrubbinn system is currently
under construction at a midwestern United States electrical power
generation site. The inlet gas stream to the scrubber contains
2200 ppm S02 and has a volumetric flow rate of about 300,000 scfm.
Approximately 150 gallons/minute of recycled stream will be removed
from the sodium absorber and will be sent to an evaporator. Within this
evaporator, steam will strip the solution, and a S02 effluent with an approx-
imate strength of 85 percent will be liberated. This strong S02 gas stream
will be used for the production of elemental sulfur. A purge stream
of about 15 gallons/minute will be removed from the evaporator and
then sent to a crystal!izer unit. Chilling of the purge stream in
the crystal!izer unit will cause the contained sodium sulfate to
8-24
-------
selectively crystallize. The remainder of the purge stream, which
will principally contain sodium sulfite, will be recycled to the
evaporator. The final crystallized salt will contain 70 percent
sodium sulfate and 11 percent sodium thiosulfate, ana the remainder will
be sodium sulfite. This crystallized salt will then be sent to a
conventional pulp mill, where it will be used as a chemical make-up.
One possible chemical make-up application is with black (spent) liquor
in a recovery boiler. Smelt (molten salt), composed principally of
sodium sulfide and sodium carbonate, is removed from the bottom of
the recovery boiler. This mixture is then dissolved in a water
tank and treated with lime. The final solution, termed "white liquor,"
is a combination of sodium hydroxide and sodium sulfide and is
commonly used to produce pulp from wood chips. "Black liquor" is
the solution that results from this pulping operation. Therefore, one
"secondary pollution free" application of the purge stream from the
sodium scrubber is available.
In summation, the purge stream from the sodium-based scrubbing
system has the potential to produce water pollution through
C.O.D. and dissolved solids when discharged without treatment to a
water course. Current practice is the acidification of this purge,
with the resultant discharge solution containing nearly all sodium
sulfate, thus eliminating the possibility of C.O.D. All interested
parties are presently attempting to develop a method to safely consume
or dispose of this purge. Double-alkali shows promise as an adequate
disposal method. Usage of the crystallized form of the purge in the
conventional pulp mill may also prove to be a viable approach.
8-25
-------
DfnrethylaniLinfc (QM& Scrubbing —
The dimethyl aniline scrubbing technique has been successfully
applied to a portion of the sinter machine off-gases of a domestic
lead smelter (no longer operating) and a segment of the process gas
straws of a domestic copper-pyrite operation. The DMA system will
shortly be used to concentrate the S02 contained in the converter effluent
at one domestic copper smelter and a combination of the reverberatory
furnace and converter effluents at a second copper smelter.
Basically, the gas stream which is to be scrubbed enters a three-
section scrubbing tower. The effluent first makes contact with the DMA
in the lower section of the scrubber. The DMA chemically removes a
majority of the S02 contained in the gas stream. The effluent next
passes through the second section of the tower which contains a dilute
sodium carbonate scrubbing solution. This solution removes most of
the remaining SO,,, as well as entrained DMA, from the effluent;
the sodium carbonate is converted to sodium sulfite and bisulfite. The
third section of the tower contains a dilute sulfuric acid solution,
which removes, as DMA sulfate, any dimethyl am'line vapors contained
in the gas stream. The gas stream, scrubbed of S02 and DMA, is then
released to the atmosphere. The liquid effluents from the second and
third sections of the tower empty into a collection tank. DMA is
separated from the solution in a regenerator. The regenerator
reaction products between the DMA sulfate and the sodium sulfite-bisulfite
are free DMA (which is recycled back to the tower), SC^, and sodium
sulfate. The resulting purge stream.contains mostly dissolved solids,
in the form of sulfates and sulfites of sodium, and trace amounts of DMA.
8-26
-------
The volume of this solution and its sodium salt content are principally
dependent upon DMA plant capacity, the DMA scrubbing tower operating
temperature, and the S02 content of the treated gas stream. The pH
of the waste stream is maintained between 5 and 6. If the pH were
to fall below 5, a larger amount of DMA would be lost to the purge
stream, whereas if the pH were to rise on the basic side of 6, the
effluent would contain a greater amount of sodium sulfite. The pH
of the system can easily be maintained between five and six.'^
To illustrate the approximate magnitude of waste effluent which the
DMA process could produce, assume that the absorption (scrubbing) tower
operating temperature is 30°C. If the gas stream being scrubbed
contains 5 percent S02, by volume, approximately 40 pounds of N32S04
is formed in solution per ton of S02 recovered. If the S02 concen-
tration were 0.5 percent, with all other factors being equal, approxi-
mately 400 pounds of Na£S04 would be formed in solution for each
15
recovered ton of
This effluent is not recycled. If it were discharged directly
to a water course without prior treatment, the possibilities of water
pollution by means of C.O.D. and dissolved solids could exist.
Because DMA is an organic compound, it is assumed that the DMA in
high concentrations could also produce water pollution.
A primary lead smelter, which was closed in late 1969, employed
DMA on part of its sinter effluent and discharged its DMA waste stream
directly to a sewer without prior treatment. This plant was located
near tidal (saline) waters and the DMA discharge presumably did not
produce secondary pollution. 14,15 This same DMA unit is currently
8-27
-------
operating on an effluent from a sulfur burner; the purge is discharged
directly to the tidal waters, with no indications of secondary
pollution.16
One existing smelter which utilizes two DMA units to produce liquid
S02 will shortly initiate the construction of a water purification
system which will be a form of double alkali. The purge stream from
the two DMA units has a flow rate varying from 20 to 25 gallons/minute.
This effluent has the following average analysis:
25 ppm DMA
45,000 ppm dissolved solids (principally as sulfates and sulfites
of sodium)
18 ppm suspended solids
5.8 pH
The purge will first pass through an activated carbon filter to remove
DMA, and the outlet concentration of DMA after filtering will be less
than 5 ppm. The solution will then join other plant effluents, all
of which will then be neutralized with lime. Calcium sulfate and
sulfite will precipitate out and the solid will be sent to an impound-
ment area, from which the final effluent will be discharged to a local
river. The company anticipates that the spent activated carbon can be
safely land-filled in enclosed containers.
An existing domestic primary copper smelter is currently constructing
a DMA unit, which will concentrate the S02 contained in a portion of the
smelter's converter effluent J4J5 The waste by-product effluent from
the DMA unit is planned to be used for cooling of converter gases in a
balloon flue (this should reduce SCL formation) and as a gas stream
conditioner prior to electrostatic precipitation. It is anticipated
8-28
-------
t
k
that most of the waste solution will become a component of the
electrostatic precipitator dust, which will be shipped to a lead
smelter for further processing.
i
A DMA jnit is currently being "lined-out" at another domestic
°| O
primary copper smelter. This smelter is integrated in that it
produces both copper concentrate and blister copper on-site. The
purge stream from the DMA unit will vary between 30 and 50 gallons
per minute, depending on the gas stream being treated by the unit.
The pH of the purge stream will be maintained between 5 and 6 and,
under normal operating conditions, will contain approximately
0.15 ml DMA/1 of purge (150 ppm DMA, by volume). This effluent
will combine with nearly 4500 gallons per minute of tailings flow
from the copper concentrating operation. The entire flow will
then proceed to the tailings pond area. Water in these ponds
is recirculated back to the concentrating department, thus providing
a closed-loop effluent operation. During a one- to two-day period
of each month, the concentrator will not operate, and the DMA purge
effluent will proceed to a special waste pond. No recirculation
will occur from this pond. The concentration of DMA contained in
the purge stream will be visually controlled by the DMA plant operator.
(With low concentrations of DMA, the effluent is colorless, whereas
if the DMA content is excessive, the effluent color becomes purple.)
The company states that no secondary pollution from this purge stream
is anticipated.
In summation, the DMA purge stream contains mostly sodium sulfate
and sulfite with trace quantities of DMA. If this effluent were
released directly to a water course, the possibility of water pollution
8-29
-------
by means of C.O.D., dissolved solids, or DMA content could exist.
Since, as shown by the text of this section, various means for
minimizing secondary pollution exist, or have adequately demonstrated
potential, DMA should not provide a secondary means for contamination
of the environment.
Calcium-Based Scrubbing Systems —
This type of S02 control device has not been directly applied
to effluents of the primary domestic lead, zinc, and copper industries.
Basically, a gas stream containing SC>2 is scrubbed with a lime or a
limestone slurry; the clean gases are released to the atmosphere while
the S02 -laden slurry is split with one portion flowing to a pump tank
and the other portion going to a settler. This settler, in most situations,
would be a settling pond. Ideally, calcium sulfite and calcium
sulfate are precipitated out in the settler as a solid by-product which
can be disposed of easily and the liquid effluents from both the pump
tank and the settler are recirculated back to the scrubber.
As was discussed in 4.3.1, scaling may produce operation problems
within the system. One method currently used to reduce the amount of
scaling is to discharge to a local water course a portion of the liquid
effluent from the scrubber. Water pollution derived by this discharge
is possible. This liquid discharge would invariably contain calcium
and magnesium as unreacted carbonates, various sulfates and chlorides
of calcium and magnesium, and possibly dissolved salts of trace metals
which were contained in the scrubbed gas stream. Thus, in discharging
this effluent directly to a water course, the possibility of water
pollution by means of dissolved solids, chemical oxygen demand, and
increased hardness of water can exist. Other pollution produced by the
8-30
-------
release of soluble magnesium salts, as well as salts of various
trace metals, is possible. If this effluent discharge were to produce
water pollution, water purification methods would have to be utilized
prior to the discharge.
Calcium-based systems of the future will be designed in such a
fashion that closed-loop operation can be practiced. With this type
of operation, the possibility of water pollution by means of the direct
discharge of the scrubber effluent to a local water course will be
minimal. For this analysis, it will be assumed that the calcium-based
scrubber has been designed to compensate for the problems derived
from scaling. Since there will be no discharge to local waters
and since the liquid effluent will be in a closed circuit within
the scrubbing system, one would expect the various concentration
of materials contained in the scrubber slurry to build up with time.
Secondary pollution which would be produced by such a system would now
be that of solid waste: the disposal of the calcium sulfate and
calcium sulfite sludge. This sludge material will contain a large
amount of water, the relative magnitude of which would depend almost
solely upon economics. Pilot plant studies of calcium-based
systems have thus far indicated that this sludge, after dewatering,
has the consistency of toothpaste. Final disposal of the material
with such a consistency is difficult. The underlying problem which
causes the retention of large amounts of water by the calcium-sulfate-
sulfite material is its crystalline structure. Initial investigations
for determination of the optimum crystal structure for minimal water
retention has indicated that large crystals of calcium sulfate are
desirable.f
8-31
-------
Assuming that the calcium-based systems which may be used in
the future on primary metallurgical gas streams for sulfur dioxide
control will have closed-loop effluents, the potential of water
pollution by means of direct discharge of the effluent will be minimal.
Ponding capacity and structure will have to be designed in order to
insure minimum water pollution potential by means of seepage and runoff.
Optimal crystalline structure will have to be determined to insure
that the calcium sulfate-sulfite sludge formed by this scrubber can
be easily and economically dewatered, thus allowing the final
disposal or commercial usage of this solid by-product.
8-32
-------
8.2 ENERGY IMPACT
Summary—
The impact of the proposed NSPS on the energy requirements associated
with the production of copper, zinc and lead will, in most cases, be
minimal. Since the proposed NSPS will encourage the domestic smelting
industry to abandon existing smelting technology in favor of newer
smelting technology, the impact of the NSPS can only be analyzed by compar-
ing the energy requirements of the new smelting technology with emission
control to the energy requirements of conventional domestic smelting
technology without emission controls. Since compliance with the NAAQS by
new smelters will also in most cases encourage the domestic smelting
industry to abandon existing smelting technology in favor of newer smelting
technology (see Section 6 - Summary), the incremental impact of the NSPS
over compliance with the NAAQS can be analyzed by comparing the energy
requirements of the different emission control systems which would be
utilized in each case.
On the basis that only one of the two or three new copper smelters
which are likely to be constructed by 1980 will employ electric smelting
and the remaining one or two will employ flash smelting, the overall
impact of the NSPS will result in a net decrease of some 10-20$ in
the energy requirements associated with the copper produced by these smelters.
This is in comparison with the energy requirements that would be associated
with the copper produced by these smelters if they employed conventional
domestic smelting technology and incorporated no emission controls.
8-33
-------
With regard to zinc and lead smelters, the impact of the proposed
NSPS would result in an increase in the energy requirements associated
with the production of zinc and lead by about 1-5% and 5-10%, respectively.
This again is in comparison with the energy requirements that would be
associated with the production of zinc and lead if the zinc and lead
were produced in smelters employing conventional domestic technology and
incorporating no emission controls.
The incremental impact of the proposed NSPS on the energy requirements
associated with the production of copper, zinc and lead over that of
compliance with the NAAQS is minimal. In most cases, the difference in
the energy requirements associated with double-absorption sulfuric acid
plants over those associated with single-absorption sulfuric acid plants
essentially represents this incremental impact. Although double-absorption
sulfuric acid plants require about 15% more energy to operate than single-
absorption sulfuric acid plants, the incremental impact in
terms of the increase in the overall energy requirements associated with
the production of a unit of copper, zinc or lead is only about 2%.
General Discussion--
The energy requirements associated with most conventional metallurgical
extraction processes are quite high. The production of aluminum,for
example, is one of the most energy-intensive metallurgical extraction
?
processes and requires in the range of 70,000-90,000 BTU per pound of aluminum
The energy requirements associated with the production of copper, zinc and
lead are considerably less than this, although still significant in
comparison. Conventional reverberatory furnace smelting as used by the
domestic copper industry, for example, requires in the range of 10,000-20,000
8-34
-------
BTU per pound of copper, and the smelting of zinc and lead by the domestic
primary smelting industry requires in the range of 20,000-40,000 BTU per
pound of zinc and about 10,000 BTU per pound of lead.2!
Evaluation of the impact of the proposed NSPS in terms of the
increased energy requirements associated with the production of copper,
zinc, and lead involves not only an examination of the energy requirements
of the emission control systems required to comply with the NSPS, but also
an examination of the energy requirements of the basic smelting processes.
As discussed in Sections 6 and 7, compliance with the proposed NSPS will
in most cases require the adoption of different smelting processes by the
domestic copper smelting industry and, to some extent, by the domestic lead
smelting industry. Specifically, the proposed NSPS will encourage the
domestic primary copper smelting industry to abandon reverberatory smelting
furnaces in favor of flash or electric smelting furnaces, and the domestic
primary lead smelting industry to abandon conventional sintering machines
in favor of sintering machines employing gas recirculation.
Tables 8-2, 8-3 and 8-4, therefore, summarize not only the energy
requirements associated with the emission control systems required to
comply with the proposed NSPS for copper, zinc and lead smelters, but
also the energy requirements associated with the various smelting processes.
The energy requirements shown in these tables are taken from detailed
energy balances developed by EPA, which are included in this document as
Appendix IV.
The energy requirements associated with the emission control systems
in Tables 8-2, 8-3 and 8-4 are based on the use of DMA scrubbing on weak
8-35
-------
en
c
4J
(/»
+J
i
3
S"
a:
%
t-
O)
c
LU
*O
L.
+•>
C
O
o
c
o
•r-
C
£
"oj
c
4J
*0)
J
vj
u
£
•M
U
f
t/i
IT)
LZ
>
S-
o
4J
2
Ji
S-
11)
>
0)
CXI
C
•r-
V)
•r- C
& 3
» «r-
C7) r— o >-i cn r*. I
e« a>
i2 :s ii i ii ii
*^*LO «*• «3 ^-%in m ...
JQ • . • 0 • . I
•^CT> ^-o —a> p»
t— i ai »— i cf> '
^"s ^^
XI U
HH o m «"m vovo
I-H . • •-> • • •
HHO r-o M '"S '~0
-a oi «a- o
%— . . ... V--LO O • O O O 5> • • •
>-< r-» || | HI co CM o
S. S- J-
0) 01 0)
a. Q. Q.
a. a. a.
o o o
u u u
JO XI C XI
,— r-O I—
•*^ ^^'»- "^^
=3 =3 «•> =3
1— 1— - VI C/l f-
M+J +•> M-Pl. »«4-> -4->
CCK9 C3 CCIO
"(DON " i- 3 t- 4J -r- 4-' i- 3 i.
C3TO-t-> C3i— C3T3+J
O CT O 3 OCTlO OCTO3
• oaitLai • o cu i-S •oaislai
o a: a. r jO- -Qi =^ & te. a. e
iT.-r Zr— 0)Zr—
i— >i 0 -0 i— >, g i— >)T> TJ
O)&-&.uu o)t-s-«— OIL.L.UO
"O OJ 0) ^ ^ *O(UO>L±J ^90)0) < ^
o>c o>c o^c
so LU zo ui Z>OLU
xi in "^ u u>
^^ • o *— ' • . ,
H-IOI •-• ro I) 1
l-l Ol !>. 1-1 r— || |
O
CM
>8J 1 1 1 1 1 1 1
m
i^I
xi in cn ^^ o
^ . . o ^ i
•-ten ID <~* ro |
01 r- 1-1 CM
in
rx •
--» o ^- ^
XI •— 0 >^
**x ^^ ^M^m ov
•"* ro . . , "^ ' •
t~t • || | i— i 00 O
«0 0 III «» "
"
«»• r-.
r~
XI -v, ^^ »^
— • o . . . u in >—
>• • \ •*-• •
•-•o vo I 1 >eo r~
r^ r— >-* cn i—
L. O t- S» O
ai •" £ £ •?
Q.-U a. Q-+J
>— a. ia o. o. ia
| S^ 8 8^
c xi n xi c xi 15
51— t- •— O t— t
^ •*-> *** »r- ^* +*
= 3 S+* =5
c v—
0 CO C CO 3 CO C
1- T3
v> z -a z: p s: -a
VI "^ i- f
•r- « (J « Q. » U
g vi a ui IA -^ M4Jfc. M -P ^.
c c c a c e
•Q "(DO '^OIM- **0)O
I/I O S -U O&3 O S +J
VI L.S.U S- t- (fl J- t- O
01 4-> -1- 3 -U 'r- 4J 1- 3
U C 3 TD C 3 •— C 3 TJ
2 .8S"£ .5STJ3 .3^1
T£O ceo. o ace oasa.
^^ Z r~ Z^~ Ol Z »•-
i— >>T3 t— >, E r- •S'O
"ffl "flj t- S-U '(UL.l.r- >«l.™'u
•p -aaiax •aaiaiui •aa>a><
•2 Ic55 S55 i«§5
8-36
-------
0)
§*
•(-> IO
o o
•is
Ot t
o: 01
in co
. .
OO
.
— vo
1-1 Ol
— -vo
1-1
>> O
O? S-
LO co
. .
O O
ro
s?
sr
LU D)
C
+J Ol
O 1^
0 o
c c
o i-
•i- M
V)
V)
O
2
O
CM
O O MO
fi CTl
CO
10
o
CM
o
CM
LO
CM
CO
ci
0)
s
ID
U
c
f^
^_
I—
00
X
„
U)
c
t/l i.
U) T-
01 3
o cr
O 0)
O-
••- s_
U) Ol
10 C
CQ LU
U
C
_Q
p—
1—
3E
• O
Wl -r-
»« 4J +J
C C IO
i — * Q) O N
£r— E •*— •!—
O (D 4->i—
•P i. V. O IO
C •!-> -r- 3 S-
3C 3 -O •»->
o cro 3
• 0 1)S- O)
c o ce o-c
0 Zr-
I/I r- "lO O)'"- -i-
Ul Ol S- I. O O
•i- -O Ol Ol C
LU a: o LU
U
c
-Q C
i— O
?'•£
CQ 3
s:l>
• Q.
V>
»< -l-l S-
^.g^
i- t_ 1/1
o cr"(a
• o 01 +J
o a: c
r— IO Q) 5
ai s- s-i—
•a 01 0) LU
o > c
£ O LU
c
o
^^J
£
c
o
U
c
0
in
tr_
fi
aB
U)
ai
U
£
CL.
__
1o
o
1—
U 4->
c n)
•i- N
M -t-
J3 *IO
r- t-
13 3
1— O>
CO C
x -o
« o
(/) (0
" QJ O
i- i. U
+J -i- 3
C 3-D
O CT O
• o a< s.
o o: CL
r-"io o?5
Ol I- i- O
T3 Ol Ol «t
u
c
•r-
-Q C
r— O
= *J
CO 3
^l
« Q.
to
C 3
« Ol t-
"o S's
C 3 •—
o o- 10
• 0 01 <->
o a: c
Z •— 0)
•— >, E
i — 10 oS a)
01 S- S-r-
z: OLU
8-37
-------
S-
o
•o
C ID
O CU
IO
00
cu
-a
10
CD
o
"O •!->
CU Nl
•o
IO
0)
-a +J
SfO
N
ca
s:
to
4->
C
(U
cr
i
10 t-
IO 'i-
CU 3
o cr
o cu
i- ce
Q.
>>
o cn
•r- !_
(O CU
10 C
00 UJ
ca
z:
£Z
" O
t/> "r-
»«•!-> *->
i— " CU O N
S- O CU -4-» i —
•4-> S- S- -r- 3 S-
O C 3 "O 4->
O O CTO 3
• O CU t. CU
C O C£ O. C
O Z r—
"- i— >>-0 -0
V) 1 — IO Cn-i- -r-
(O CU i- 1- U U
•r- -O CU 01 c
LU z: o LU
CO 3
T3
" Q.
CO
fc£ -l-> S.
C 3
* CU *^
2CD 3
i- 10
4-> -r-
C 3 i —
O cr 10
• O CU +J
O B£ C
^" >> £
"cu i- i- i—
•o cu cu uj
o > c
s: o LU
CO
s:
c
• o
to -r-
»« 4-> +->
C C IO
* CU O N
O S •!-> i —
S- i- U ID
4-> ••- 3 l-
O CT O 3
• <-> 01 i- 0)
o o: o. c
F- >)T3 -0
i — IO CT'«~ *i~
CU S- S- U U
•O 0) c
z: o uj
O CQ C CO 3 COC
•c— "O
10 z: -o z: o z: T3
CO •!- S- •!-
•r- « O - Q. « U
1 1 1 ^^ ^j *^ ^^ ^j ^ ^^ 4J ^^
c c c 3 c c:
+ "OIO "CUM- "0)O
to O CU +J O Ol 3 O Ol 4-*
(O &.&-U L.&.IO &.L.U
CU -U -r- 3 +-> -i- -!-» ••- 3
U C3~O C3« — C3T3
o ocro ocrio ocro
S- • <_> CU !- -LJCU-M • O CU S-
O. O O^Q. O C£EI O C£Q.
i— >>-O i— >> E r— >>T3
1o "cui-S-o "cus-s-i— "ois-s-o
+J -OCUCU<: T3CUCULU -OOlOl-C
O O>C O > C O>C
h- zrouj z: o LU ZIOLU
8-38
-------
off-gas streams (<3.5% SCL) and double-absorption sulfuric acid plants on
strong off-gas streams (>3.5% S02); or the use of DMA scrubbing on high-
oxygen off-gas streams (>5% CL) and elemental sulfur plants on low-oxygen
off-gas streams (<5% Op). The energy requirements associated with limestone
neutralization of sulfuric acid consider only the energy required for
crushing and grinding of the limestone and that required for the neutraliza-
tion of sulfuric acid. The energy required for mining of the limestone
and transportation of the limestone from the mine site to the smelter are
not included.
t.
" With regard to the energy consumption or the various emission control
systems, the production of elemental sulfur requires considerably more
' energy than the production of sulfuric acid, even if the acid must be
neutralized. As shown by Tables 8-2, 8-3 and 8-4, the production of
elemental sulfur requires from 4 to 6 times the energy required for the
production of sulfuric acid per pound of copper or lead, and from 8 to
12 times the energy required for the production of sulfuric acid per
pound of zinc. Although these numbers are quite sensitive to the overall
processing sequence utilized to produce elemental sulfur and they reflect
the fact that elemental sulfur plants require tail-gas scrubbing to comply
with the proposed NSPS, there is no doubt that elemental sulfur plants
require more energy than sulfuric acid plants.
It is the consumption of large quantities of fossil fuels such as
r
natural gas that results in the large energy requirements associated with
elemental sulfur plants. Neglecting the electrical energy requirements,
» elemental sulfur plants of the Allied Chemical type (see Section 4.2)
8-39
-------
require about 0.6 volume of methane per volume of sulfur dioxide reduced
to elemental sulfur, even when reducing off-gases of low oxvgen content
(<0.5% Op).22 This is equivalent to an energy consumption of about 6.5 MM
BID per ton of sulfur dioxide reduced. Double-absorption sulfuric acid
plants,however, normally require little or no fuel (see Section 4.3),
and thus the energy requirements associated with the production of sulfuric
acid are solely electrical energy requirements to operate pumps, blowers
and other process equipment. As a result, only about 150 KWH of
electrical energy are required per ton of sulfur dioxide converted to
sulfuric acid." This is equivalent to only about 1.5 MM BTU per ton of
sulfur dioxide.
In comparison with the difference in energy requirements associated
with elemental sulfur plants and double-absorption sulfuric acid plants,
the difference in energy requirements associated with double-absorption
acid plants and single-absorption acid plants is quite small. Where
double-absorption acid plants require about 150 KWH of electrical
energy per ton of sulfur dioxide converted to sulfuric acid, single-
absorption acid plants require about 130 KWH of electrical energy per
y
-------
basically a function of the total volume of gases treated, rather than
the amount of sulfur dioxide recovered. Consequently, when off-gases
containing low concentrations of sulfur dioxide are treated, the associated
energy requirements per unit of sulfur dioxide recovered are extremely
high, and when off-gases containing high concentrations of sulfur dioxide
are treated, the associated energy requirements per unit of sulfur dioxide
recovered are considerably lower.
DMA scrubbing,for example, requires only about 110 f&IH per ton of
sulfur dioxide recovered when treating off-gases of 5% sulfur dioxide,
but requires about 940 KWH per ton of sulfur dioxide recovered when
treating off-gases of 0.5% sulfur dioxide. Thus, when used to treat
off-gas streams similar to those that could be treated by sulfuric acid
plants, DMA scrubbing requires about the same amount of energy as a
sulfuric acid plant. However, when used to treat off-gases with low
concentrations of sulfur dioxide, the energy requirements per unit of
sulfur dioxide recovered increase by as much as an order of magnitude.
In terms of the impact of the proposed NSPS on the energy require-
ments associated with the production of copper, zinc and lead, the data
summarized in Tables 8-2, 8-3 and 8-4 indicate that the NSPS should have
little impact. With regard to copper smelting, the proposed NSPS would
increase the energy requirements associated with conventional domestic
reverberatory furnace smelting from 9,000-15,000 BTU per pound of copper to
10,000-16,000 BTU per pound of copper, with or without neutralization of the
sulfuric acid produced. This represents an increase of only 5-10%.
8-41
-------
However, as indicated in Sections 6 and 7, the impact of the emission-
control costs associated with the proposed NSPS will encourage the domestic
copper smelting industry to abandon reverberatory furnace smelting and
adopt electric furnace or flash furnace smelting. The energy requirements
associated with electric furnace smelting are comparable to those associated
with reverberatory furnace smelting and are in the range of 10,000-16,000 BTU
per pound of copper. The impact of the proposed NSPS would increase these
energy requirements to 12,000-17,000 BTU per pound of copper, which represents
an increase of 10-20%.
The energy requirements associated with flash furnace smelting,however,
are considerably less than those associated with reverberatory furnace
or electric furnace smelting (see Section 3), and are in the range of
only 5,000-6,000 BTU per pound of copper. The impact of the proposed NSPS
would increase these energy requirements to about 7,000-7,500 BTU per pound of
copper. Since the energy requirements of flash furnace smelting are
considerably lower than those of either reverberatory furnace or electric
furnace smelting, this represents an increase of 25-35%.
To analyze the actual impact of the proposed NSPS,however, the overall
energy requirements associated with the production of a unit of copper
under the NSPS should be compared with the energy requirements associated
with the production of a unit of copper in conventional domestic smelters
before the advent of air pollution control regulations, andwith the energy
requirements associated with the production of a unit of copper in a new
smelter under the NAAQS (National Ambient Air Quality Standards).
8-42
-------
From the point of view of the impact of the proposed NSPS on the
energy requirements associated with the production of a unit of copper
before the advent of air pollution control regulations, the data in
Table 8-2 indicate that this impact depends on whether electric furnace
smelting or flash furnace smelting is utilized in place of reverberatory
furnace smelting. In those cases where electric smelting furnaces are
utilized, the impact of the proposed NSPS would be to increase the net
energy requirements associated with the production of a pound of copper
by from 10 to 30%, depending on whether the smelter employed a green charge
furnace or calcine charge furnace. In those cases where flash smelting
furnaces are utilized, the impact of the proposed NSPS would be to
decrease the net energy requirements associated with the production of a
pound of copper by from 15 to 55%, depending on whether a calcine charge
,or green charge reverberatory furnace would have been employed.
As a result, in terms of assessing the impact of the proposed NSPS
on the energy requirements associated with the production of a unit of
copper for the domestic copper smelting industry as a whole (in comparison
with the energy requirements before the advent of air pollution control
regulations), both the number of new smelters and the types of smelting
technology they will emplov need to be projected. As discussed in
Section 6, from two to three new copper smelters are likely to be
constructed within the United States by 1980, depending on the possible
closure of the Phelps Dodge Douglas, Arizona, smelter. Projecting the
type of technology these smelters will employ, however, is somewhat more
difficult. This would involve an analysis to project the composition of
the copper concentrates and the amount of cement copper and secondary
8-43
-------
copper scrap to be smelted, and the likely location of each of these
new smelters to determine the availability of electrical power and
various cost parameters, An analysis such as this is beyond the scope of
this report.
However, from the review of the various smelting technologies
undertaken by EPA's engineers in the development of this document, the
general consensus is that,in most cases, flash smelting appears more
attractive than electric smelting, in a major part due to the significantly
lower energy requirements associated with flash smelting over electric
smelting. Only in those cases where the various limitations of flash
smelting come into play (see Section 3) is electric smelting likely to
be more attractive. Consequently, it appears to EPA that flash smelting
will be employed at most new copper smelters,and of the two or three new
smelters that are likely to be built by 1980, only one might possibly
employ electric smelting. On this basis, the overall impact of the NSPS
will result in a net decrease in the energy requirements associated with
the copper produced by these new copper smelters by some 10-20%.
From the point of view of the impact of the proposed NSPS on the
energy requirements associated with the production of a unit of copper at a
new copper smelter, compared to the impact of compliance with the NAAQS,
indications are that the incremental impact of the NSPS over that of the NAAQS
will be minimal. As discussed in Section 6, most of the states in which
copper smelters currently operate have submitted to EPA SIP's (State
Implementation Plans) to attain and maintain the NAAQS, which include
regulations limiting sulfur dioxide emissions from new copper smelters to
8-44
-------
10% or less of the input sulfur to the smelter. The impact of these regula-
tions will be the same as that of the proposed NSPS in terms of encouraging
the domestic copper smelting industry to abandon reverberatory smelting
furnaces and adopt electric smelting or flash smelting furnaces (see Section 6).
As a result, the incremental' impact of the proposed NSPS above the NAAQS will
be minimal and will reflect the use of double-absorption sulfuric acid plants
over single-absorption sulfuric acid plants. Although,as mentioned earlier,
double-absorption sulfuric acid plants require about 15% more energy to
operate than single-absorption sulfuric acid plants in terms of the overall
energy requirements associated with the production of a unit of copper, the
incremental impact of the NSPS over compliance with the NAAQS represents
only a 2% increase in energy requirements.
With regard to the impact of the proposed NSPS on primary zinc and
lead smelters, Tables 8-3 and 8-4 indicate the NSPS will increase the
energy requirements associated with the production of a pound of zinc or
lead by about 1-5% for zinc smelters and about 5-10% for lead smelters,
compared to the energy requirements associated with the production of zinc
and lead if the smelter were uncontrolled.
Also, as with those states in which copper smelters currently operate,
those states in which zinc and lead smelters currently operate have
submitted to EPA SIP's to attain and maintain the NAAQS, which include
regulations limiting sulfur dioxide emissions to 10% or less of the input
sulfur to the smelter, or in some cases, to 500 ppm or less. Consequently,
as with the proposed NSPS for copper smelters, there will be little or
no incremental impact of the proposed NSPS for zinc and lead smelters above
that of the NAAQS in terms of increasing the energy requirements associated
with the production of a unit of zinc or lead.
8-45
-------
REFERENCES FOR SECTION 8
Morris, J.S. Potential Water Quality Problems Associated with
Limestone Wet ^Scrubbing for SO? Removal from Stack Gas. Prepared
for Presentation at Second International Lime/Limestone Wet
Scrubbing Symposium, New Orleans, Louisiana, Nov. 8-12, 1971,
p. 300.
* 2n!Sr0!; i?'S-'Jr; Personal comnuni cations from Mr. Maddin
Kennecott Copper Corp., Hurley, N.M., April 24, 1973; US EPA,
3. Plaks, N. Personal communications from Mr. J.M. Henderson, ASARCO,
South Plainfield, N.J., March 13, 1972, U.S. EPA, RTP, N.C.
4- Process Research, Inc. Neutralization of Abatement-Derived
Sulfuric Acid. EPA-R2-73-187. April 1973.
5. Thompson, G.S.,Jr. Personal communications from Mr. J. Bland,
Allied Gnomical Corp., Newell, Pa., May 24, 1973, U.S. EPA,
ESED, SDB, RTP, N.C.
6. Thompson, G.S., Jr. Personal communications from Mr. Munson,
01 in Corporation, Beaumont, Texas. May 25, 1973, U.S. EPA,
ESED, SDB, RTP, N.C.
7. Slack, A.V. Sulfur Dioxide Removal from Waste Gases 1971.
Noyes Data Corp., Park Ridge, N.J. , pp. 114-131.
8. McNally, R.J., Spedden, H.R., and Apps, J.A. Sulfur, Sulfuric Acid,
and Pollution Problems, Part I: The Treatment of Mine Waters with
Acid Bisulfite. Presented at AlChE Sixty-Third Annual Meeting,
Chicago, 111., Nov. 29 - Dec. 3, 1970, p. 16.
9. Thompson, G.S., Jr. Personal communication from Mr. J. Osborne,
Davy Power Gas, Lake'land, Florida. June 5, 1973, U.S. EPA, ESED,
SDB, RTP, N.C.
10. Thompson, G.S., Jr. Personal communication from Mr. H.T. Emerson,
01 in Corporation, Paulsboro, N.J. June 5, 1973, U.S. EPA, ESED,
SDB, RTP, N.C.
11. Draemel , D.C. Regeneration Chemistry of Sodium-Based Double-
Alkali Scrubbing Process. EPA-R2-73-186, March 1973, p. 5.
12. Thompson, G.S., Jr. Personal communication from Mr. G. Welch,
St. Joe Minerals Corp., Monaca, Pa. June 6, 1973. U.S. EPA,
ESED, SDB, RTP, N.C.
13. Thompson, G.S., Jr. Personal communication from Mr. R. Chrisman,
U.S. EPA, CSD, RTP, N.C. June 6, 1973, U.S. EPA, ESED, SDB, RTP, N.C.
8-46
-------
14. Thompson, G.S., Jr. Personal communication from Mr. J.N. Henderson,
ASARCO, South Plainfield, N.J. June 7, 1973, U.S. EPA, ESED, SDB,
RTP, N.C.
15. Farmer, J.R. Personal communication from Mr. J.M. Henderson, ASARCO,
South Plainfield, N.J. March 15, 1973, U.S. EPA, ESED, SDB, RTP, N.C.
16 Thompson, 6.S., Jr. Personal communication from Mr. Rue, Virginia
Chemicals, Portsmouth, Va. June 8, 1973, U.S. EPA, ESED, SDB,
RTP, N.C.
17. Thompson, G.S., Jr. Personal communication from Mr. S.L. Norwood,
Cities Service Company, Copperhill, Tenn. June 7, 1973, U.S.
EPA, ESED, SDB, RTP, N.C.
18. Thompson, G.S., Jr. Personal communication from Mr. J.E. Foard,
Phelps-Dodge Corp., Ajo, Arizona. June 7-8, 1973, U.S. EPA, ESED,
SDB, RTP, N.C.
19. Thompson, G.S., Jr. Personal communication from Mr. J.S. Morres,
TVA, Chattanooga, Tenn. June 13, 1973, U.S. EPA, ESED, SDB, RTP, N.C.
20. Air Pollution Control in the Primary Aluminum Industry; A study done
for EPA by Singmaster & Breyer, New York, N.Y.; Contract No. CPA 70-21;
July 23, 1973.
21. See Appendix IV.
22. W.D. Hunter and J.C. Fedoruk; Application of Technology for SO?
Reduction to Sulfur in Emission Control Systems; Paper presented at
Antinquinamento '72 - Milan Trade Fair; Milan, Hay; Nov. 17, 1972.
23. Based on an off-gas stream composition of 6% S02. See Section 6.
24. See Section 6.
8-47
-------
APPENDIX I
Material Balances for Model Smelters
-------
Figure 1-1. Model copper facility - Case I(a),
material balance
Concentrates
1
Electric
Furnace
1
Slag
1
Converters
••MMM
(D ^ Single -Stage
9 Acid Plant
F
Sulfuric
Acid
/
Copper
hr/day
SCFM
% SO?
* 02
hr/day
SCFM
% S0?
% Oo
hr/day
SCFM
% S09
% 0 *
H2S
\v
24
24,100
6
15
5
85,700
6.75
11.75
5
77,200
0.20
5
61 ,600
7
10.5
11
54,900
6.5
12.5
11
49,600
0.20
-\
11
30,800
7
10.5
2
56,200
8.5
12.5
2
49,100
0.20
&>
2
32,100
10.5
10.5
5
87,000
8
11.75
5
76,700
0.20
5 1
62,900
8.75
10.5
1
24,100
6
10
1
22,000
0.20
24
927 TPD
(100%)
1-1
-------
Figure 1-2 Model Copper Smelting - Material Balance for Case I(b)
Concentrates
i
Electric
Furnace
Slag
Converters
I
I®
Dual-Stage
Acid Plant
(
4
Su If uric
Acid
Copper
hr/day
SCFM
% SO?
% 02
hr/day
SCFM
% S02
% 02
hr/day
SCFM
% SO?
% 02
H2S04
U/
24
24,100
6
5
5
85,700
6.75
11.75
5
77,100
0.05
5
61 ,600
7
10.5
11
54,900
6.5
12.5
(
V
11
49,600
0.05
V
11
30,800
7
10.5
f«\
W
2
56,200
8.5
12.5
sv
y
2
49,100
0.05
Q
2
32,100
10.5
10.5
5
87,000
8
11.75
5
76,600
0.05
5
62,900
8.75
10.5
1
24,100
6
10
1
21 ,900
0.05
1
-
-
"
24
944 TPD
(100*)
1-2
-------
Figure 1-3. Model copper facility - Case I(c),
material balance
Concentrates
Electric
Furnace
I
Slag
Converters
Copper
Natural
Gas
Elemental
Sulfur
Plant
SulTur
.
hr/day
SCFM
% SO?
%o2L-
hr/day
SCFM
% S02
% 02
u;
24
24,100
6
15
2
56,200
8.5
10.25
61
10
87
10
5
,600
7
.5
5
,000
8
.25
-/Ev-
il
30,800
7
10.5
1
24,100
6
15
^
32
10
10
97
6
2
,100
.5
.5
5
,200
.5
62
8
10
62
6
5
,900
.75
.5
11
,000
.5
1
85
6
10
2
65,800 101
8 7
.-fc\. ,
^
5
,700
.75
.25
5
,000
.75
y
11
54,900
6.5
10.25
1
27,000
6
hr/day 5 11 2 5 1 5 11 2 5 1
SCFM 6400 3900 5300 7700 1600 11,500 7100 9600 14,000 2900
% S02 100 100 100 100 100 5.5 5.5 5.5 5.5 5.5
% 02
hr/day
SCFM
% S02
% 02
Sulfur
5
90,800
0.05
11
58,100
0.05
W
2
60,500
0.05
5
93,300
0.05
1
25,400
0.05
24
308 TPD
Reduction Methane
hr/day 5 11 2 5 1
SCFM 2800 1800 2400 3500 700
1-3
-------
Figure 1-4. Model copper facility - Case I(d),
material balance
Concentrates
J
Electric
Furnace
Slag
Converters
DMA
Unit
Liquid
Sulfur Dioxide
1
r
Copper
hr/day 24
SCFM 24,100
% SO? 6
% 02 -15
hr/day 5
SCFM 85 ,700
% SO, 6.75
% o2z
hr/day 5
SCFM 80,000
% S02 0.05
SCFM 5700
% SO? 100
V
5 11
61,600 30,800
7 7
10.5 10.5
11 2
54,900 56,200
6.5 8.5
fS\
(3)
11 2
51,400 51,400
0.05 0.05
3500 4800
100 100
fc/
2
32,100
10.5
10.5
5
87,000
8
5
80,100
0.05
6900
100
5 1
62,900
8.75
10.5
1
24,100
6
1
22,700
0.05
1400
100
1-4
-------
Figure 1-5. Model copper facility - Case II(a),
material balance
Concentrates
\ '
Flash
Furnace
\
Converter
i '
Slag
Treatment
hr/day
SCFM
% S02
% 02
hr/day
SCFM
% SO?
% o2
hr/day
SCFM
% S02
H2S04
1 ,
Slag Coi
® 4
(|) to Sinqle-Staae
9 Acid Plant
i
s i >(&
Sulfuric
Acid
Dper
/^\
24 9 4 10 1
28,100 15,900 16,500 32,400
10.25 7 10.5 8.75
5 10.5 10.5 10.5
9 4 10 1
54,100 58,200 73,000 39,200
7.5 8 7.75 7.25
9.5 10.25 10.25 9.5
9 4 10 1 24
48,100 51,300 64,600 35,000
0.2 0.2 0.2 0.2
929 TPD
(100%)
1-5
-------
Figure 1-6. Model Copper Smelting - Material Balance for Case Il(b)
Concentrates
Flash
Furnace
Converters
u
Slag
Treatment
Slag
Copper
Dual-Stage
Acid Plant
I'
Sulfuric
Acid
hr/day
SCFM
% S09
% ^2
hr/day
SCFM
% SO?
% Q2
hr/day
SCFM
% SOo
HoSO-
c. 4
U>
24
28,100
10.25
5
9
54,100
7.25
9.5
9
48,000
0.05
9
15,900
7
10.5
f?
\i
4
58,200
8
10.25
(J!
Vi
4
51 ,200
0.05
V£
4
16,500
10.5
10.5
\
;
10
73,000
7.75
10.25
s
)
10
64,500
0.05
J
10
32,400
8.75
10.5
1
39,200
7.25
9.5
1
35,000
0.05
1
-
-
™*
24
945 TPD
(100%)
1-6.
-------
Figure 1-7. Model copper facility -Case H(c),
material balance
Concentrates
Flash
Furnace
4
,500
.5
.5
10
,100
.75
10
6300
100
; —
32
8
10
34
9
10 1
,400
.75
.5
1 9
,000 47,700
.5 0.05
1 9
3200 8100
100 5.5
9
44,000
9
/
v
4
49,000
0.05
fl
\L
4
9500
5.5
46
10
?N
&J
65
0
1
/
11
5
— v«
4
,000
.25
10
,800
.05
10
,600
.5
&
10
60,500
9.5
1
30,800
0.05
1
5900
5.5
1
28,100
10.25
24
309 TPD
Reduction Methane
hr/day 9 4 10 1
'SCF.M 2100 2500 3000 1500
1-7
-------
Figure 1-8. Model copper facility - Case
material balance
Concentrates
1
Flash
Furnace
(3)
Converters
Slag
Treament
i
DMA
Unit
Liquid
Sulfur Dioxide
Slag
Copper
hr/day
SCFM
% S02
% 02
hr/day
SCFM
% SO?
\L>
24
28,100
10.25
5
9
40,100
0.05
15
10
40
0
9
,900
7
.5
Ct
^
4
,000
.05
^
4
16,500
10.5
10.5
JV
tr-
io
54,800
0.05
ir
32
8
10
25
0
10
,400
.75
.5
1
,200
.05
1
_
-
™
9
3900.
100
9
44,000
9
/f
\1
4
4600
TOO
W
4
44,600
10.25
=\
V
10
5700
100
V
10
60,500
9.5
1
2900
100
1
28,100
10.25
1-8
-------
Figure 1-9. Model copper facility - Case III(a),
material balance
Concentrates
1
Roaster
Reverberatory
Furncce
Slag
Converters
Copper
Single-stage
Acid Plant
Sulfuric
Acid
hr/day
SCFM
% S02
% 02
hr/day
SCFM
% S02
X 02
hr/day
SCFM
% S02
H2S04
\v
24
45,600
2.25
. 5
2
58,000
7.5
9.75
2
51,600
0.2
vs/
24
17,100
10
5
9
40,800
7.25
9.5
9
36,400
0.2
2
36,800
7
10.5
4
45,800
8.25
10.5
4
40,200
0.2
9
18,400
7
10.5
8
62,900
8
10.25
8
55,500
0.2
Vsy
4
19,300
10.5
10.5
1
23,600
7.25
9.5
1
21,100
0.2
8
37,700
8.75
10.5
24
1
-
1-9
748 TPD
(100%)
-------
Figure 1-10. Model copper facility - Case III(b),
material balance
Concentrates
1
Roaster
Reverberatory
Furnace
Slag
Converters
Copper
Dual-Stage
Acid Plant
Sulfuric
Acid
hr/day
SCFM
% S0
hr/day
SCFM
% so?
% 02
hr/day
SCFM
% S02
W
24
45,600
2.25
5
2
58,000
7.5
9.75
2
51,500
0.05
w
24
17,100
10
5
9
40,800
7.25
9.5
9
36,400
0.05
2
36,800
7
10.5
4
45,800
8.25
10.5
4
40,200
0.0*
9
18,400
7
10.5
8
62,900
8
10.25
8
55,400
0.05
\^~-
4
19,300
10.5
10.5
1
23,600
7.25
9.5
1
21 ,000
0.05
8 1
37,700 -
8.75
10.5
<5>
1-10
760 TPD
(100%)
-------
Figure 1-11. Model Copper Smelting - Material Balance for Case III(c)
Concentrates
1
Roaster
I
Reverberatory
Furnace
sfg
Converter
I
Copper
DMA
Unit
1
Dual-Stage
Acid Plant
Su If uric-
Ac id
hr/day
SCFM
X S02
% 0-y
hr/day
SCFM
% S02
% 0
hr/day
SCFM
% S09
% Oo
u>
24
45,600
2.25
5
2
64,400
8
10.5
2
56,700
0.05
V2)
24
44,700
0.05
-
9
47,300
8.25
10l75:
9
41 ,500
0.05
(3)
24
900
100
-
4
52,300
8.75
11.5
4
45,500
0.05
-------
Figure 1-12. Model copper facility - Case IV(a),
material balance
Concentrates
Reverberatory
Furnace
Slag
Converters
I
Copper
Single-Stage
Acid Plant
I
Sulfuric
Acid
hr/day
SCFM
% S0?
% 02
0
24
82,600
1.75
5
5
61,600
7
10.5
11
30,800
7
10.5
2
36,900
9
11.75
5
65,500
8.5
11
hr/day
SCFM
* SOo
X 02
H2S04
5
55,200
0.2
11
27,600
0.2
2
32,000
0.2
5
57,300
0.2
24
651 TPD
(100%)
1-12
-------
Figure 1-13. Model copper facility - Case IV(b),
material balance
Reverberatory
Furnace
Slag
Converters
1
Copper
Dual-Stage
Acid Plant
I
Sulfuric
Acid
hr/day
SCFM
X SOa
% o2
hr/day
SCFM
X SO?
H2S04
W
24
82,600
1.75
5
5
55,200
0.05
5
61 ,600
7
10.5
11
27,600
0.05
^
11
30 ,800
7
10.5
2
31 ,900
0.05
)
2
36,900
9
11.75
5
57,200
0.05
5
65,500
8.5
11
1
-
-
1
-
-
™
24
660 TPD
(100%)
1-13
-------
Figure 1-14. Model Copper Smelting - Material Balance for Case IV(c)
Concentrates
i
I
Copper
t
Reverberatory
Furnace
S
i
lag
i
r
Converters
DMA
Unit
\
1 ®
' *. Dual-Staae
^ Acid Plant
Sulfuric
Acid
hr/day 24
SCFM 82,600
SO
1.75
5
24
81,200
0.05
24
1400
100
5
61,600
7
10.5
11
30,800
7
10.5
2
32,100
10.5
10.5
5
62,900
8.75
10.5
hr/day 5 11 2 5 1
SCFM 67,600 38,800 53,000 75,600 15,700
% SOo 8.5 9 9 9 9
% Oo 11 11.75 11 11.75 19
hr/day 5 11 2 5 1
SCFM 59,000 33,600 45,900 65,400 13,600
% SOo 0.05 0.05 0.05 0.05 0.05
24
937 TPD
(100%)
1-14
-------
Figure 1-15. Model zinc facility - Case I(a),
material balance
Concentrate
Roasting
Sintering
Reduction
i
Refining
T
Zinc
Single-Stage
Acid Plant
Sulfuric
Acid
Baghouse
hr/day
SCFM
% S02
% Op
g/sCF
24
36,300
7
9
24
32,600
0.2
0
24
36,000
0.2
0.02
487 TPD
1-15
-------
Ffgure 1-16. Model Zinc Smelter - Material Balance for Case I(b)
Concentrate
i
I
Sintering
I
Reduction
Refining
Zinc
t
Baghouse
Dual-Stage
Acid Plant
Sulfuric
Acid
hr/day
SCFM
% S02
% Op
g/sCF
H2S04
24
36,300
7
9
24
32,500
0.05
24
36,000
0-2
0.02
24
497 TPD
1-16
-------
Figure 1-17. Model zinc facility - Case I(c),
material balance
Concentrate
I
Roasting
J
Sintering
J
Reduction
1
Refining
Zinc
f©
® ©j* Dual-Staqe
* i * Acid Plant
J Sulfuric
® Acid
^
hr/day 24
SCFM 20,800
* SO,
% 02Z
H2SD4
12
24
71,800
0.1
24 24
71,700 100
0.05 100
24
37,000
7
9.25
24
33,100
0.05
24
497 TPD
(100%)
1-17
-------
Figure 1-18. Model zinc facility - Case I(d)
material balance
I
Roasting
Sintering
Reduction
I
Refining
Zinc
Sulfur
Plant
f
fu
Sulfur
t
We11 man
Scrubbing
Baghouse
hr/day
SCFM
% SO?
c.
% Oo
g/SCF
24
21,500
12
24
21,800
13.25
24
29,000
1
0
24
28,700
0.05
0
24
300
100
24
35,900
0.2
0.02
24
165 TPD
Reduction Methane
hr/day 24
SCFM 1400
1-18
-------
Figure 1-19.
Model zinc facility - Case 11(a),
material balance
Concentrate
Roasting
f©
Single -Stage.
Acid Plant
Leaching and
Purification
Sulfuric
Acid
Electrolytic
Extraction
Zinc
hr/day
SCFM
% S02
% 0?
H2S04
24
37,500
7
9
24
33,700
0.2
495 TPD
-------
Figure 1-20. Model Zinc Smelter - Material Balance for Case II(b)
Concentrate
1
Leaching
and
Purification
Electrolytic
Extraction
Roasting
fe
Dual-Stage
Acid Plant
Sulfuric
Acid
Zinc
hr/day
SCFM
% S0?
% 0?
g/sCF
24
37,500
7
9
24
33,600
0.05
0
24
505 TPD
1-20
-------
Figure 1-21. Model zinc facility - Case II(c),
material balance
Concentrate
Roasting
Leaching and
Purification
Sulfur
Plant
Sulfur
Wellman
Scrubbing
Electrolytic
Extraction
hr/day
SCFM
% S(L
% 0 2
q/S6F
Sulfur
24
21,500
12
0
24
21,800
0
24
29,000
1
0
0
24
28,700
0.05
0
24
300
100
0
n
24
166 TPD
Reduction Methane
hr/day 24
SCFM 1400
1-21
-------
Figure 1-22. Model zinc facility - Case III(a),
material balance
Concentrate
Sintering
t
Single-stage
Acid Plant
Recirculation
Gas Cleaning
Reduction
Refining
Zinc
hr/day
SCFM
% SO
' O
% 022
g/SGF
24
72,200
5.0
6.5
24
66,900
0.2
0
24
58,000
0.5
24
673 TPD
1-22
-------
Figure 1-23. Model Zinc Smelter - Material Balance for Case III(b)
Concentrate
i i 1®
Sintering
1
k. Dual -Stage
w Acid Plant
I^ Recirculation I (D
t
Reduction
1
Refining
System Siiif.iHr
Acid
Zinc
hr/day
SCFM
% S02
% Op
g/sCF
24
72,200
5
6.5
24
66,800
0.05
0
24
58,000
0.5
24
703 TPD
1-23
-------
Figure 1-24. Model zinc facility - Case III(c),
material balance
Concentrate
Sintering
Reduction
Refining
Zint
1
DMA Unit
Recirculation
Gas Cleaning
System
Sulfur
Plant
P
Sulfur
hr/day
SCFM
% S02
% 02
g/SGF
Sulfur
24
72,200
5.0
6.5
24
58,000
0.5
24
79,400
5.0
24
75,500
0.05
0
24
3900
100
24
24
7200
5.5
0
229 TPD
Reduction Methane
hr/day 24
SCFM 1900
1-24
-------
Figure 1-25. Model lead facility - Case I(a),
material balance
i
i
Single-stage
Acid Plant
Sulfuric
Acid
Concentrate
1
Sintering
Machine
Blast
Furnace
T
Slag
Dross
Furnace
Lead
Baghouse
Baghouse
hr/day
SCFM
% S02
% 02
g/sCF
24
80,400
0.5
24
80,400
0.5
0.007
24
18,600
6.5
12.0
0
24
16,800
0.2
8
0
24
22,500
0.5
12
hr/day
SCFM
% S02
% 02
g/sCF
HoSOd
24
230 TPD
(100%)
24
42,500
0.3
19
0.007
24
20,000
1-25
-------
Figure 1-26. Model Lead Smelting - Material Balance for Case I(b)
Concentrate
Sintering
Machine
|
m act
o last
Furnace
j 1
Slag 1
Dross
Furnace
fl
©
®
T(D
1
w
3>
®
Dual -Stage
Acid Plant
^if^"^
J®
Sulfuric Acid
Lead
hr/day
SCFM
% S02
% 02
g/S&F
24
80,400
6v5
24
80,400
0.5
0.007
24
18,600
6.5
12.0
0
24
16,800
0.05
8
24
22,500
0.5
12
H2S04
24
236 TPD
(100%)
24
42,500
0.3
19
0.007
hr/day
SCFM
% SQ2
% 02
g/sCF
24
20,000
1-26
-------
Figure 1-27. Model lead facility - Case I(c),
material balance
Concentrate
1
J_
Sintering
Machine
Blast
Furnace
Dross
Furnace
\
Lead
Dual-Stage
Acid Plant
J<
Sulfuric
Acid
Baghouse
SCFM
% SO?
tm
%02
SCFM
% SOe
gr/SCF
H2S04
80,400
0.5
(2)
316 TPD
/ 1 nna/ \
80,000
0.05
®
22,500
0.5
400
100
(D
20,000
18,600
6.5
12
©
42,500
0.02
19,000
8.5
11.75
16,600
0.05
1-27
-------
Figure 1-28. Model lead facility
Case I(,&>, material balance
Concentrate
t
1
'
Sintering
Machine
\
r
Blast
Furnace
i
1
r
Dross
Furnace
@
j
'
-------
Figure 1-29. Model lead facility - Case 11(a),
material balance
Concentrate .
1 t*
Sintering
Machine
i
r
Blast
Furnace
;
i
r
Dross
Furnace
G) ^ Single-Stage
*• Acid Plant _
S
I
®
1(D
ulfuric
Acid
Lead
(D
hr/day
SCFM
% S02
* 0?
g/scF
H2S04
24
33,000
5.0
6.5
24
30,600
0.2
0
24
306 TPD
22,
0.5
19
24
42,500
0.3
0.007
24
20,000
1-29
-------
Figure 1-30. Model Lead Smelter - Material Balance for Case II(b)
Concentrate
Sintering
Machine
-------
Figure 1-31. Model lead facility - Case II(c),
material balance
Concentrate
Sintering
Machine
Blast
Furnace
Dross
Furnace
Lead
t®
Dual-Stage
Acid Plant
t.
Sulfuric
Acid
DMA Unit
Baghouse
SCFM
f S02
2
33,000 22,500 22,400
5.0 0.5 0.05
6.5 19
100 33,700 31,100
100 5.25 0.05
6.75
SCFM
% SOo
gr/SCF
H2S04
20,000
347 TPD
(100%)
20,000
0.02
1-31
-------
Figure 1-32. Model lead facility - Case II(d),
material balance
Concentrate
t
Sintering
Machine
i
r
Blast
Furnace
1
i
r
Dross
Furnace
CD O
0
t
-*- UIVIH urn t
©
f.
®
** Bagnouse
<3>
i •
Sulfur
Plant
Sulfur
Lead
hr/day
SCFM
% S02
% 0?
Sulfur
hr/day
SCFM
% S0£
hr/day
SCFM
24
33,000
5.0
6.5
24
22,500
0.5
19
Reduction
24
36,300
5.0
24
20,000
0.3
Methane
24
900
24
34,500
0.05
24
T _-
24 24
1800 3300
100 5.5
24
104 TPD
-------
Figure 1-33. Model lead facility - Case III(a),
material balance
Concentrate
t<
Electric
Furnace
1
i
r
Converter
i
r
Dross
Furnace
® ® ^ Sinqle-Staqe
i
" Acid Plant
I®
Sulfuric
Ac ic
t
Lead
hr/day
SCFM
% SOo
%o2
hr/day
SCFM
% S02
X 02
HoSOA
W
24
10,000
10
0
/
V
22
14,700
0.2
(&
2
18,000
8
14
TV
3)
2
27,700
0.2
W
22
16,200
6.25
8.0
219 TPD
(100%)
2
31,100
7.5
10.25
1-33
-------
Figure 1-34. Model Lead Smelter - Material Balance for Case III(b)
Concentrate
Electric
Furnace
Slag
1
>
Converter
1
Dross
Furnace
k Acid Plant
*
Sulfuric
Acid
_L
Lead
hr/day
SCFM
% S02
% Op
H2S&4
Sulfur
24
10,000
10
2
18,000
8
14
22 2
16,200 31,100
6.25 7.5
8 10.5
@~
22
14,700
0,05
2
27,600
0.05
24
224 TPD
1-34
-------
Figure 1-35. Model lead facility - Case III(c),
material balance
Concentrate
i
Electric
Furnace
Slag
Converter
Dross
Furnace
Lead
0
DMA Untt
Sulfur
Plant
I
hr/day
SCFM
% S02
% o2
hr/day
SCFM
%S02
W
22
10,000
10
— —f,
^!
22
1100
100
V6/
2
18,000
7
14
?v
y
2
2500
100
•\
22
10,000
10
22
2000
5.5
&
2
28,000
8
9
3\
z)
2
4600
5.5
22
10,900
0.05
24
a>c
2
30,100
0.05
i;
22
12,000
9.25
V
2
32,600
7.75
fo ^o
Sulfi
ur
70 TPD
Reduction Methane
hr/day 22 2
SCFM 500 1200
1-35
-------
Appendix II
Outline of Group II-A NSPS Development
-------
Appendix II
Outline of Group II-A NSPS Development
Date
9/16/71
5/2/72
5/72
5/72
6/72
Development Activity
Surveyed and reviewed process operations and
emission control systems at all domestic
copper (15), lead (6) and zinc smelters (10)
Meeting with American Mining Congress to explain
and discuss NSPS development (Washington, D.C.)
Meeting with American Mining Congress to discuss
EPA emission testing program and the general
aquisition of data by EPA (Durham, N.C.)
Emission testing program formulated and specific
copper, lead and zinc smelters selected as test
sites.
Zinc smelter emission testing program initiated
and completed:
one single-absorption sulfuric acid plant
operating on off-gases from a fluid-bed
roaster tested at the ASARCO zinc smelter
in Columbus, Ohio (5/23-27/72)
Lead smelter emission testing program initiated
and completed:
one baghouse operating on the off-gases
from the blast furnace tested at the
ASARCO lead smelter in Glover, Missouri
(5/15-17/72)
one single-absorption sulfuric acid plant
operating on the strong off-gas stream from
the sintering machine tested at the Missouri
Lead smelter in Boss, Missouri (5/23-27/72)
Copper smelter emission testing program initiated
and completed:
a) two single-absorption sulfuric acid plants
operating on the off-gases from copper converters
tested at the Kennecott copper smelter in
Garfield, Utah (6/12-16/72)
II-l
-------
one single-absorption sulfuric acid plant
operating on the off-gases from the copper
converters tested at the ASARCO copper smelter
in Hayden, Arizona (6/19-23/72)
7/72-8/72 Review of the technical literature and contacts
with various engineering design/construction
firms to identify "well-controlled" foreign
copper, lead and zinc smelting operations.
8/72-9/72 Specific European and Japanese copper, lead and
zinc smelters contacted and visited to observe
and discuss process operations and emission
control systems.
9/72 Letters sent to various domestic copper, lead
and zinc smelters requesting specific information
pertaining to process, emissions and economic
factors under Section 114 of the Clean Air Act.
Plans formulated for long-term continuous monitoring
of sulfur dioxide emissions from a single-absorption
sulfuric acid plant operating on the off-gases from
the copper converters at the Kennecott copper
smelter located in Garfield, Utah.
9/28/72 Meeting with the American Mining Congress to
discuss purpose and intent of EPA letters
requesting information under Section 114 of
the Clean Air Act (Durham, N. C.)
9/72-11/72 Developed first draft of EPA Technical Report -
Primary Copper, Lead and Zinc Smelters for
inclusion in the NSPS Background Information
Document - Primary Copper, Lead and Zinc Smelters.
Reviewed possible options concerning both the
identification of affected facilities to which
the NSPS should apply and the type of emission
limitation which should be incorporated into
the NSPS.
10/72-12/72 Continuous monitoring of sulfur dioxide emissions
from a single-absorption sulfuric acid plant
operating on copper converter off-gases at the
Kennecott copper smelter carried out.
11-2
-------
11/1-2/72
11/20/72
11/30/72
12/12/72
12/19/72
12/72-2/73
1/73
2/73
Meeting with NAPCTAC to review first draft of the
Technical Report - Primary Copper, Lead and Zinc
Smelters (Washington, D.C.)
Meeting with Primary Non-Ferrous Smelter Working
Committee to review the development of NSPS for
copper, lead and zinc smelters and to solicit
information from other programs within EPA
concerning the impact of copper, lead and zinc
smelter NSPS in various environmental sectors
other than air (Durham, N.C.)
Meeting with the American Mining Congress to review
first draft of the Technical Report - Primary
Copper, Lead and Zinc Smelters (Durham, N.C.)
Meeting with NAPCTAC to review the selection of
affected facilities to which the NSPS is applicable
and the type of emission limitation incorporated
into the NSPS (Denver, Colo.)
Meeting with Federal Agency Liaison Committee to
review the development of copper, lead and zinc
NSPS and the Technical Report - Primary Copper,
Lead and Zinc Smelters (Washington, D.C.)
Developed emission control costs associated with
various NSPS for a wide range of emission control
strategies and smelting processes
Letters sent to various sulfuric acid plant vendors
requesting specific information pertaining to
operation and emissions from both single-and
double-absorption acid plants.
Letters sent to various European and Japanese
copper, lead and zinc smelters requesting specific
information pertaining to emissions from double-
absorption acid plants.(Replies in answer to
these inquiries were never received in most cases.)
Letters sent to various off-gas scrubbing system
vendors requesting specific information pertaining
to operation and emissions from various off-gas
scrubbing systems
II-3
-------
3/73
4/73
4/27/73
4/73-7/73
5/31/73
6/73
6/12/73
6/29/73
Evaluation of continuous monitoring emission data
gathered on a single-absorption sulfuric acid plant
operating on the off-gases from the copper converters
at the Kennecott copper smelter at Garfield, Utah
Plans formulated for continuous monitoring of sulfur
dioxide emissions from
1. a double-absorption sulfuric acid plant
operating on the off-gases from the copper
converters at the ASARCO copper/lead smelter
in El Paso, Texas
2. a DMA off-gas scrubbing system operating on the
off-gases from both the reverberatory furnace and
the copper converters at the Phelps-Dodge copper
smelter in Ajo, Arizona
3. an ammonia off-gas scrubbing system operating
on the combined off-gases from a lead sintering
machine at the Cominco lead smelter in Trail, B.C.,
Canada
Meeting with Monsanto and Davy Power Gas (formerly
Wellman Power Gas) to discuss in depth operation and
emissions from both single-and double-absorption
sulfuric acid plants (Durham, N. C.)
First draft of the proposed NSPS and the Background
Information Document—primary copper, lead and zinc
smelters developed.
Meeting with NAPCTAC to review proposed NSPS and the
Background Information Document (Raleigh, N.C.)
Continuous monitoring of sulfur dioxide emissions
from a double-absorption sulfuric acid plant operating
on the off-gases from the copper converters at the
ASARCO copper/lead smelter in El Paso, Texas,initiated
Meeting with the American Mining Congress to review
the proposed NSPS and the Background Information
Document (Durham, N.C.)
Meeting with the American Mining Congress to discuss
the concept of modification (Washington, D.C.)
II-4
-------
7/73-9/73
7/73
9/73
9/6/73
10/9/73
10/17/73
10/29-11/4/73
11/73
11/9/73
Proposed NSPS and the Background Information
Document reviewed by EPA's Office of the
Assistant Administrator for Air and Water Pro-
grams and by the EPA steering committee
Continuous monitoring of sulfur dioxide emissions
from a DMA scrubbing system operating on the off-
gases from a copper reverberatory smelting furnace
and copper converters at the Phelps-Dodge copper
smelter in Ajo, Arizona,initiated
Continuous monitoring of sulfur dioxide emissions
from an ammonia scrubbing system operating on the
off-gases from a lead sintering machine at the
Cominco lead smelter in Trail, British Columbia,
Canada,initiated
Meeting with Mr. J. Henderson, representing the
American Mining Congress, to discuss the proposed
NSPS and the Background Information Document (Durham, N.C.)
Proposed NSPS and the Background Information Docu-
ment submitted to the Federal Agency Liaison for
distribution to,and review by, the various Federal
agencies
Proposed NSPS and the Background Information Docu-
ment distributed to EPA Regional Offices for review
Opacity of effluent emissions released to the
atmosphere from a double-absorption sulfuric acid
plant and a lead blast furnace baghouse at the
ASARCO El Paso, Texas, copper/lead smelter monitored
and recorded
Contract initiated with the Arthur D. Little Co. in
Boston, Massachusetts, to investigate both the limi-
tations of copper flash and electric smelting com-
pared to conventional domestic copper reverberatory
smelting, with regard to the elimination of impurities
and the ability to process copper precipitates
and secondary copper scrap, and the impact of these
limitations on the domestic copper smelting industry
Meeting with Dr. P. Queneau and Dr. H. Kellogg of
Dartmouth College and Columbia University, respectively,
to discuss the proposed NSPS and the Background Informa-
tion Document (Hanover, N. H.)
II-5
-------
n/n
12/73-1/74
1/74-2/74
1/25/74
t/M/74
8/22/74
Continuous monitoring of sulfur dioxide emissions
from the double-absorption sulfuric acid plant
at the ASARCO copper/lead smelter in El Paso, Texas,
and the ammonia scrubbing system at the Cominco lead
smelter in Trail, British Columbia,brought to a con-
clusion
Comments received from various Federal agencies con-
cerning the proposed NSPS and the Background Informa-
tion Document reviewed and evaluated
Second draft of the proposed NSPS and the Background
Information Document developed
Meeting with Mr. F. Tempieton representing the American
Mining Congress to discuss the concept of modifications
as related to the NSPS (Durham, N. C.)
Opacity of effluent emissions released to the
atmosphere from a lead blast furnace baghouse
at the ASARCO El Paso, Texas, copper/lead smelter
observed and recorded.
Meeting with NAPCTAC to review draft regulations
for modified sources under section 111 of the Act.
Representatives of American Mining Congress commented
on draft regulations as related to copper smelters.
II-6
-------
Appendix III
Analysis of Continuous SO? Monitor Data and Determination of an Upper
Limit for Sulfunc Acid Plant Catalyst Deterioration
-------
-------
Appendix III
Analysis of Continuous S02 Monitor Data and Determination of an Upper
Limit for Sulfuric Acid Plant Catalyst Deterioration
Emission Variation
Sulfur dioxide emissions from the No. 7 sulfuric acid plant, which
is the newest of five single-stage absorption plants that are operating
on the off-gases from the nine Kennecott copper converters at Garfield.
Utah, were analyzed. The emissions were recorded by a DuPont #460
Continuous S02 Analyzer from September 15, 1972, to November "16, 1972.
This instrument is capable of measuring $62 concentrations within +
150 ppm (2% of full scale) and automatically zeroes itself every 8-1/2
minutes. The zero calibration procedure requires 1-1/2 minutes; thus
the instrument is "on-line" 85% of the time.
A general review of the data generated revealed that several
periods of data were missing due to problems with the recorder. Other
segments contained long periods of plant shutdowns for maintenance
or included concentrations that were obviously greater than the
upper limit of the monitor. (A shorter absorption tube could have
been installed to increase the upper limit of the monitor, if this
situation had been noticed sooner.) Consequently, on the basis of
data legibility and continuity, the periods of October 11-27, 1972,
and November 8-15, 1972, were selected as representative of the
two-month monitoring period.
Periods of emissions during which the average concentration
appeared to be greater than 3000 ppm or less than 1000 ppm were
then noted. Eighteen periods during which emissions exceeded 3000
ppm, including two periods during which emissions exceeded the
recording capacity of the DuPont analyzer (7500 ppm), were identified.
Fourteen periods during which emissions were less than 1000 ppm were
also identified. Acid plant operating logs and inlet SO? volume
and concentration continuous monitor data were analyzed to ascertain
if upsets, malfunctions, or startups and shutdowns occurred during
these periods.
One major upset/malfunction was discerned. This occurred during
one of the two periods during which the emissions exceeded the
recording capacity of the analyzer. The upset/malfunction resulted
from prolonged low inlet S02 concentrations which caused a decrease
in the normal temperature increase across the first catalyst bed.
Consequently, this period of excessive emissions was deleted from the
data. Six shut-downs and start-ups were noted. The six periods of
low emissions following these shutdowns were deleted from the data
because the acid plant was not in operation. Two periods of high
emissions were identified following two of the six start-ups. These
III-l
-------
two periods of high emissions were also deleted from the data. Due
to the time constraints placed on the analysis of these data, no
investigation of why four of these six start-ups had no associated
periods of high emissions was conducted. A brief investigation of
the eight remaining periods during which emissions were less than
1000 ppm, however, did reveal that these low emissions appeared to
be the result of almost ideal operating conditions within the acid
plant, with somewhat low inlet gas volumes and S0£ concentrations
and a minimum of fluctuations in either of these variables.
Following this review of acid plant operating data, fifteen
periods during which emissions were higher than 3000 ppm remained.
This included one of the two periods previously identified as
periods during which emissions exceeded the capacity of the DuPont
analyzer. This period was then deleted from the data for the follow-
ing reasons. First, and most important, since no knowledge
concerning numerical values of emissions was available, this time
period could not be mathematically accounted for in the analysis.
Second, because emissions were apparently so great,this period
of operation would represent a violation of any reasonable standard
developed and thus would add nothing to the analysis of "normal"
operating emissions data to provide a basis for such standards.
The long-term S02 emissions concentration average was then
calculated for all the data generated during the "normal operating"
portions of the October 11-27 and November 8-15 periods. Fifteen-
minute instantaneous S02 concentration values were used for this
calculation, and the long-term emission average was determined
to be 1700 ppm. It is significant to note that this value is
considerably less than the emission concentration corresponding
to Monsanto's guaranteed conversion efficiency of 95% conversion
of S02 to SOs at 5% S02 inlet, i.e., approximately 2700 ppm.
The fourteen periods of high emissions that were not deleted
from the data were then examined by averaging these periods over
various time intervals using the fifteen-minute instantaneous S02
concentration values identified during the above analysis. The time-
averaged concentrations were then compared to various outlet S02
concentration levels to determine the extent to which such averaging
periods mask variations in outlet concentration. The results are
tabulated in the attached Tables III-l and TII-2.
Seven of the fourteen high-emission periods exceeded 2700 ppm
(equivalent to the manufacturer's guarantee) when averaged for a
six-hour duration. Increasing the averaging time to seven hours
decreased the number of periods exceeding 2700 ppm to five. Further
increases in the averaging period resulted in only minor decreases
in the number of periods exceeding 2700 ppm. Increasing the level
of average S02 emission concentration from 2700 ppm to 3000 ppm
III-2
-------
(approximately 10%) caused a significant reduction of the number
of high-emission periods that exceeded this level as compared with
2700 ppm. For each time-averaging interval, the number of periods
for which the averages exceed 3000 ppm is about half the number of
periods corresponding to 2700 ppm. Increasing the level of average
S02 emission concentration from 2700 to 3250 ppm (approximately 20%)
resulted in only a slight decrease in the number of periods exceeding
this level compared to the number of periods exceeding 3000 ppm. In
general, therefore, increasing either the averaging time to periods
greater than six hours, or increasing the average SO? emission
concentration selected for comparison by more than 10% above the
manufacturers guarantee, does not significantly decrease the number
of high-emission periods that exceed the level of S02 emission
concentration selected for comparison.
Another approach is to examine the actual time during which S02
emissions exceeded various selected concentration levels, such as
2700, 3000, and 3250 ppm. These data are tabulated in Table II1-2. An
examination of these data leads to the same conclusions presented
above. Thus, based on this analysis and not considering catalyst
deterioration, it appears that an averaging time of six hours is
suitable for determining S02 emission concentrations, and that
emissions levels established somewhat above commonly accepted vendor/
contractor guarantees by 10-20% could be viewed as acceptable for
purposes of allowing normal, short-term fluctuations.
Catalyst Deterioration
Due to the lack of substantial numerical qualification of the
effect of catalyst deterioration on S02 emissions from sulfuric acid
plants, S02 emission data gathered by simultaneous EPA source testing
of the No. 6 and No. 7 plants at the Kennecott Garfield smelter
during the period of June 13-16, 1972,were analyzed. The No. 6
(Parsons) plant began operating in February 1967 and was in the
second month of its twelve-month catalyst cleaning cycle during the
source test. The No. 7 (Monsanto) plant began operation in September
1970, and was in the twelfth and last month of its catalyst cleaning
cycle. The S02 emission data are tabulated in the attached Table III-3.
A statistical analysis of this data leads to the conclusion that
the 30% greater average emissions of the No. 7 plant, compared to
the average emissions of the No. 6 plant, are statistically significant
at the 90% probability level. It should be noted, however, that this
difference in emissions reflects not only catalyst deterioration but
other factors as well, such as a difference in emissions due to design
or construction variations between Parsons 1967 acid plant technology
and Monsanto 1970 acid plant technology. On the other hand, it is
probably safe to assume that the major portion of this difference
in emissions is due to catalyst deterioration. Thus, the results
of this analysis can be viewed as indicating first, that catalyst
III-3
-------
deterioration does have a significant effect on S02 emissions and
second, that with a twelve-month catalyst cleaning cycle this
difference in emissions due to deterioration appears to be of the
order of magnitude of 30%.
Additive Effect of Emission Variations and Catalyst Deterioration
As discussed above, not considering catalyst deterioration, sulfuric
acid plant performance standards based on six-hour S02 emission levels
10-20% greater than commonly accepted vendor/contractor guarantees
appear to be appropriate to allow short-term fluctuations in S02
emissions. As also discussed above, the increase in S02 emissions
during the twelve-month catalyst cleaning cycle can be estimated
to be 30%. Based on the conservative assumption that catalyst
deterioration is an increasing exponential function of time, almost
all of the effect of catalyst deterioration will occur during the
second half of the cleaning cycle. Since the emission variation data
were based on the fifth month of the catalyst cleaning cycle, the
data do not include significant catalyst deterioration and the increase
in S02 emissions due to catalyst deterioration should be added to the
allowance for new catalyst emission variation. Thus, considering
short-term fluctuations of S02 emissions and using conservative
assumptions regarding catalyst deterioration, new source performance
standards can possibly be based upon six-hour emission levels established
40-50% greater than commonly accepted vendor/contractor guarantees.
111-4
-------
Table III-l
Periods Exceeding Concentration
Concentration (ppm) 4-hr avg. 6-hr avg. 7-hr avg. 8-hr avg. 12-hr avg.
2700 13 7 5 5 3
3000 8433 1
3250 5332 0
Table III-2
Time Exceeding Concentration (Mrs.)
Concentration (ppm) 4-hr avg. 6-hr avg. 7-hr avg. 8-hr avg. 12-hr avg.
2700
3000
3250
Note
1. Percentage of time for which the emissions would exceed the reference
concentration. The total "normal" operating time of 542 hours equals
100%.
112 (21)1
61 (11
40 (7)
76 (14)1
40 (7)
30 (6)
62 (II)1
33 (6)
30 (6)
62 (II)1
33 (6)
22 (4)
42 (8)1
13 (2)
0 (0)
III-5
-------
Table III-3
Outlet SO Concentrations (ppm)
Run No. 6 Plant No. 7 Plant
2 389 296
3 753 855
4 1036 2277
5 1745 1207
6 938 1131
7 1608 2553
8 794 1104
9 1128 1355
10 930 ]433_
Average 1036 1357
III-6
-------
Appendix IV
Model Smelter Energy Balances
-------
-------
+•>
CO i—
O in
CO 1-
o o o
co in o
VD t—
CM
O
00
O
CO
in
«*•
o
to
O)
O>
to
CJ
O>
C 0)
i— O
E "*
00 O
o
•I—
4J OJ
O CT>
<1J S-
in in
o> co
CO
i o
o
o
A
in
O in
c co
01 i—
vc
o.
Q.
O
(J
O in
co «d-
CD
O
O
O
*
in
cu
c
in
Vt
O>
c
1C
3
o-
1 (Li
o:
5
s-
0)
c
UJ
r«
i
>
i—*
Ol
!o
(O
1-
0)
c
•r-
4->
S
0^
S-
O)
Q.
Q.
O
O
1
>,
IO
S-
4->
C
C
o
o
Ol
C
1— •!—
(L* O
£ r—
00 (O
o
>,
s-
o
-p
(O OJ
s- o)
(U S-
XI
(Li C
or at
O)
S-
U3
in
co
co
o
co
CO
c in
o co
CTl i—
vo
in i in
co co
co co
00
o
in
10
CD
VO
(O
CO
>>"
C S- "-0
o o -o c
•r- C E QJ
2 <0 0>T3
Ol $- -O
Q. 4J S-
o e: r- 030
•i- C U_ D-
c o
=3 O
s-
QJ
E
QJ O) (O
T3 -C i.
Ol I OJ
C S- (LI C
•i- 3 <^ O>
«/) O
CC
i
O.'
C
«-o
T3 C
C
•o
d)
S-
O)
J. B
.C Q. S-
S- S-
O).
S-
O)
O)
Ol
* 4J
E »
O) O>
-o
O)
S-
0>
in
s_
4^> S- Ol _
Tl 01 4-> Ol
10 Ol
o>
o
0
4->T3
0) (O
4§ O)
CQ
(!) "O
O C
SI
'-^J
£^
O) (Li
C «
Q- T3
,— S-
(O 0>
•O
o
col --
IV-1
------- An error occurred while trying to OCR this image.
-------
O1
c
t/1 •
10 I
l—i CT
l—i CT;
CTl
OJ
O
CO
ID
o
ID
O
1-1 01
I—i CTl
o in o
ID CT>CM
•— ID
CM
cu
O!
us
o
o
+-> v-
r- 0)
o en
QJ £-
r— (C
UJ JC
I
cs
a-.
O1
ID O
i— CO
OJ
CO
ID
O
-in
-CTl
i CTi
o o
i— CO
OJ
CO
If) O
CT> CO
CTl
CM
V)
•U
c
er
0)
ce
?
0)
ui
O)
c
•r-
O)
(O
e— -i- O)
W +J C
t/) "oJ O
i-
O)
Q.
a.
o
o
ITS
(O O)
s- cr.
OJ S-
-c
i oo
O
oo
CO
CVJ
O O
CO i—
0>
J2
a> o
>
a> c
a; a>
C 10
O TJ
J- O- C
•!-> S- -4-> «
C O C E
o ja i— -o s-
(00. -c:
• I—• t- I
O r— (U "O o
•O O Q
i
s- >.
o
•r-
•!->
(O
N
5- -r-
i—
ns
4->
-O
3 3
cr-u
O) OQ
^
•r- "^
§-3
0) CQ
i— S
•oo o
o
IV-3
-------
O)
c
o
in
o
CO
o
CM
CO
O>
(O
.c
COCJ
cr co
OJ E i- CO
cz oo 4-> c
>> J- "co'G
CO CO E i"~
s- Q- oo re
CO Q. CJ
c o >•>
Ul <_> C
o
•4->
o LT>
o
CO
CO
CO
ID
CO
ID 10
O r—
C O IT)
in CM
OJ CVJ t—
-Q (O
S- J=
O) <->
>
o> c
ctr a)
OJ
CD
u un
oo
i cr.
LO
O
in
«s-
co
LD
^»-
CO
C
0
0
o
+J
o
o
o
-o
c
re
CO
C t/>
21
££
4->
q- oo
i— (C
o o
+-> -*
C (O
re
COr—
•— a.
3-c
«• o-r-
•—•oo •
O to T3
I- CO C
•(-> c c re s-
c: -^ o E -c
o J3 ••- 5 •
J- .0 O
•— CO «C (O Q.
4J
c
CO
're s-
3 3
er+J
CO CO
§
•»->
re
N •
co
I
re i-
> ^:
••- —
. 3 3
: CT+J
. co co
'"co E
2!
•^
Si
S
i- Q.
T3 O Q
(O
-l->
i2
5
CO
re
re
co
i
re
co
i^
E <->
•££
re o
s- o
CO 01
tJ S-
(O
0)
co
4->
I/)
CO
is
•52
re
iy-4
------- An error occurred while trying to OCR this image.
-------
o
o
o>
VI +J
03 r—
O)
O)
(O
.C
o
01
c -r-
I— O
CO O
o
•r—
S-
o o>
01 S-
r— >
Ol
(U
O)
-Q
(C
CO
s_
s.
O-
o
o
c o
CO i
o
i—
(O
o
10
S- QJ
S- (O
Ol J=
> o
CD
o m
^Tod
c
o
CO
^>
in
oo
CM
c
vo
evi
e\j
in
^~
CM
O
CO
CM
(J LO
> 00
1-1 en
vo
c c
o oo
**• co
in in
oo tc
co co
s_
•r—
a-
«S
r— Q-'i- « Ol
SS JD -MO) -C
• O T- N I ecis-ro>,3>,
c -r- o -M 3 s- $_
O -Q -r- 3 -t-*>
3 Q. C 3 O CO O
•t— S- i- E o J- o
Oi— oo-a-r-ajojo)
zriococoT-cs-tJi-
s. ^3 o T- o
t— CJ ^C fl3 *O E E
a> > s:
•a o a
o
(O
Jg
i
-------
O in
r^ CM
eri co
o o
vo co
in
o
1C
c
r-~
«d-
cr>
m
vo
oo
vo
o
oo
O-i
O
r--
If,
CM
co
o in
vo r~-
in
o in in
in vo CM
r- CM
o
vo
in
i*-
co
o
oo
in
CM
in
in
00
Ol
tO
+->
c
c
o
co
o
cr
£
s-
V
&
CM
I
(O
u
ro
(O
4J
§
§
u
o
4J
o
in
in
u
ro
u
o
o
ro
J-
CU
o.
O
C
=>
S- i.
CD f
U J*
" QJ
-O J- «
C T3
re -t-> 0)
E ro -U
O) O) ro
-O .C J-
O) I Q)
•*J S (« tJ>
ui O ro
(O O- 3
O
•r- S-
•!-> -C
O I
ro 3
&. -^
4->
X «
4) -O
O ro
4J CO
>>-o
O O
cu o_
UJ
s- s_
S- 3
-C •!->
I CQ
-^
T3 «
g
CU
CT.T3
•o
ro
S- -r-
S- ru
58
C O. I
•I—
S- 3 CO
-C +J
i CQ z:
Ji^
" >>
T3 " J-
C -O CU
rO C >
E ro O
CU E O
C -a 53 o>
O T3 $-
•r- $- C
4J O) I— i— -r-
u s cu cu c
3 O 3 3 t-
T3 O- U- U. M-
JE
+J
CO
•a
c
ro
&
a>
3
U-
=> "
•!-> C
C ro
ro E
i— CO
O- T3
i— S-
ro W
CU O
C O.
c s-
CO 3
S- 4->
-i- OQ
s_ a>
JC r—
^ rO
S- >
J= -r-
I 3
5CT
o: «r-
• S- O)
>>•— 0) 3
cn cu 5 t-
S- 3 O
CU U- Ct.
cu
•r—
a-
cu
oe
g^
UJ •*->
CO
•!->
cu S
ro
CQ
co
IV-7
------- An error occurred while trying to OCR this image.
------- An error occurred while trying to OCR this image.
-------
s-
Ol
4J
03
if) LO O
in i»- ^~
CM
O
cu
o:
c
o
o
in
•<->
c
S-
O>
oo
O> i—
c: to
•r- +J o
3 I— •!-
cu
o
-CT>
' 00
o o
co co
01
CSJ
LO LO
CO
LO
o;
>>
ro
+J
c
cu
cu
'cu
s- s-
3
CO
4->
CO
O)
to
O)
C
o
+J
Q.
t.
O
ro
Ol
: 3
s-
JC
s-
2
•fj
CO
" °
O O ~^- "TD> C O^^TD
O S_O)T3C'^ O S-O>C
—' 4->C CrO3 S- 4->C+JrO
CT- roEO" 4J C'f-CS
O -Q ECUCU OO O-OroOl
O 'J-QCUT3 OXlr— T3
S- 3 -O r- H- 30.
i— S-4- S-CU O • i— SL. S-
i— O C i— CU 3 Oi— OT3CU
rot/lroHS1*- i— (/) Z s: ^->cucu>s
O -OOQ CS-T3OQ
;O +J O
ooo 2:
s
UJ csj
a
-c p
jr «
^ ^
a >
ro 3
E O-
a> cu
s-
cu
o
a.
a
iv-in
-------
01
S-
Ol
O
•r-
O
O)
o:
CJ3
O
ir>
CM
i— i en
o
CM
LO
vo
CM
-a o
o
CM
CO
I I
sz
o
o
O)
CU
s-
0)
(8
O)
OO
<0
O
•f—
+J
c
cu
c
o
o
un
CM
-co
o
U3
CM
LO
Lf)
CM
o
O
co
O CM
ro
I
c
o
O)
s
£
Ol
$
i
T3
O)
c
o
o
CO
CO
CT)
C
O
•!->
CO
M-
O S-
O 3
S- +->
+-> CO
C
O S
o s:
ns
o.
T3
•i- c:
o o
ro -r-
S« -!->
C re
" o N
"o+j ^
S-Q.ro
-U S- S-
c: o -t->
O 10 3
<_> -Q O)
o r- co -a
•Z. ro r- -r-
S- -Q O
r— CO 3 O
T3 O Q
nl
CO
i — CO
•!-> C
O
O
O r-
Z rO
S_
r^ CO
QJ >
ro
CU
cu
XJ
(O
o
s-
(/> CQ
O
a.
s- c
o o
10 •!-
CO -i-
XI ra
3 S-
O -P
• -a 3
a>
o
o
T3
M-
O
•— O E
; a. s- ro
I •(-> co
s-
•— CO '
cu >:
-o o
s-
O
Ul -
rtJ
i— CM
iv-n
-------
Appendix V
Manual Sulfur Dioxide Tests Performed at
Single-Stage Acid Plants
-------
SULFUR DIOXIDE EMISSION TEST RESULTS
Preliminary to the start of emissions testing in May 1972,
all sulfur dioxide control systems operating at domestic primary
nonferrous smelters were surveyed to determine the effectiveness
of control devices at these sources. From the source survey
evaluations, the facilities which exhibited the most advanced
control systems 1n Verms of design and reduction of SQ2 emissions
were selected for emissions test by EPA. The sources selected
Include single-absorption acid plants which treat gases from one
zinc smelter roaster, one lead smelter sintering machine, and
three copper smelter converter operations. All affected facilities
were tested for SOp emissions using Reference Method 8 contained in
Title 40 of the Code of Federal Regulations, Part 60 (40 CFR 60),
Appendix A, first published 1n the Federal Register on December 23,
1971. Later, a double-absorption add plant was Installed at a
copper smelter, and this facility was also tested. The analysis of
this test 1s Included in Appendix VI.
Single-Absorption Add Plantf
During the initial portion of the testing program, the
best domestic SO* control technology was considered to be single-
absorption add plants, described in Section 4.1, Sulfuric Acid
Plants, of this document. It was determined that a testing
program Including one acid plant at a lead smelter, one at a
zinc smelter, and three at copper smelters would give sufficient
emissions data to cover the range of smelting operations to which
standards would be applicable. That Includes the relatively
V-l
-------
constant S02 concentrations and volumetric flow rate to zinc
roaster acid plants to the highly variable Inlet SC>2 concentration
and flow rate to copper converter add plants.
All single-absorption acid plant tests wfere Initially conducted
using Method 8 of 40 CFR 60. However, to gain long-term operational
data, a continuous monitoring test program of eight weeks duration
was also conducted at one copper smelter acid plant installation.
Continuous monitoring data were required because of the unsteady
nature of some smelter S02 gas streams. Typical of unsteady emission
streams are those from copper converter operations. The converter
operation is a batch operation and, depending upon the number of
converters in operation and their phasing, will produce S02 concen-
trations and flow rates ranging from 0% to approximately 9% S02 and
a flow rate from 0 to the maximum blowing capacity of the converters.
Plant operating logs, the acid plant inlet cfm charts, absorber
and converter temperature charts and inlet concentration charts were
reviewed to determine the operating condition of the acid plant
during the continuous monitoring program. The periods of startup
and shutdown were eliminated from the data analysis. The long-term
S0« emission concentration averages; were determined from the remaining
valid data points. Finally, various averaging techniques were used
to determine the most appropriate averaging interval, thereby eliminating
the effect of massive short-term fluctuations. Similar data evaluation
procedures were used to analyze dual-stage acid plant continuous
monitoring data.
V-2
-------
Facility Test
Missouri Lead Operating Company (AMAX), Boss, Missouri
The Missouri Lead Operating Company acid plant, which treats
a portion of the effluent from a lead sintering machine, was tested
between May 22 and 24, 1972. The test consisted of three separate
runs for sulfuric acid mist and S02 emissions from the acid plant
using Method 8 of 40 CFR 60. Three runs for S02 emissions from
a weak SO, stream, using Method 6 of 40 CFR 60, were also performed.
The sintering machine is a 60 m^ Lurgi updraft machine. It has
a design feed rate of 90 metric tons per hour and a finished sinter
production rate of 40 metric tons per hour. The lead concentrate
which is processed has an analysis of approximately 70% lead and 15%
sulfur. The concentrate has only a minor amount of the impurities
found in most lead concentrates. There are two emission streams
from the machine:
(a) A strong S02 stream of approximately 22,000 scfm is ducted
to the acid plant, and '
(b) A weak S02 stream of approximately 40,000 scfm is vented
via a particulate control baghouse to the atmosphere.
The SOg concentration of the strong stream ranges between 5 and 1%
during normal operation of the sintering machine. The weak stream,
taken from the last two-thirds of the sintering machine, has an
average S02 concentration of approximately 0.4$ S02.
The sintering machine was processing approximately 1001 x 10^ kg/hr
tons/hr) of sinter, or 18,200 kg/hr (20 tons/hr) above reported
V-3
-------
normal operating conditions. The machine grate speed averaged between
0.76 and 0.82 m/m1n (30 and 32 1n/m1n). This speed 1s approximately
0.20 m/mln below normal operating speed; however, that reduction can
be attributed to the greater charge rate reported during the test.
The sulfuric acid plant is a Monsanto-designed, three-stage,
200 ton/day unit. The acid plant commenced operation in 1968.
The plant is designed to accommodate the variations in S02 concen-
trations in the inlet gas stream ranging from a low of approximately
4% S02 to a high of 8% S02- Tables 'V-l and 2 summarize the emissions
•4
test results from the strong and weak streams, respectively.
ASARCO, Columbus, Ohio
__^_^^_^_^^___^___ ^
The ASARCO primary zinc smelter at Columbus, Ohio, 1s a custom
smelter which produces zinc oxide. The facility was tested May 24-27,
1972. The test program consisted of four separate runs for sulfur
acid mist and S02 emissions from the zinc roaster acid plant; Method 9
of 40 CFR 60 was used for the test.
The smelter uses a Lurgi fluid-bed roaster to produce zinc oxide
calcine. The roaster has a design capacity of 149 metric tons per
day, and it was operating at a 155--metric-tons-per-day production
rate during the test. The average analysis of the concentrate delivered
to the roaster is 62% zinc and 30% sulfur.
A Monsanto-designed, 158-metric-tons-per-day, single-absorption
acid plant controls the emissions from the zinc roaster. It was
constructed in 1968 and has four catalytic stages. The acid plant
V-4
-------
cu
<0
4-*
>> c
c c
(O -i- CM
^M -C r^.
cu o en
Q. (0 •—
•o o> re*
CO i-
«_i £-
•r~ +^
S_ C
3 T-
O OO
CO
(/) "O
aE cu
_l
O
4J CU
CU CO
E ^
?* S»
4-> CU
•r- >
S- <
"*
CM
cn
^—
CO *
^^
CM
>^
fO
s:
CM
p^
cn
^—
CM «
CM
^^
to
•s.
CM
f^
cn
i— "
co
CM
>»J
(Q
s:
o
CM
i—
0
CM
O
CM
O
CM
X— -X
O
*• — *• — * CO
O vo .
LO 00 00
CO i— CM
r*^^^*~^^
CM
CM vo cn
00 r-
l->.
^ *—
o o
o- — -co
co vo •
"CO 00
CM i— CM
CM
vo cn
^r oo i—
CM r~v
vO
*~^ ^~^
O O
LO ^~** CO
LO I— •
"00 00
CM i— CM
^--*
co cn
i— 00 i—
co r*«»
VO
, . . — .
o o
C? •*"*•» OO
CM •— •
« cn oo
CM i— CM
CM — •»—
oo cn
i— 00 r—
CM |v.
VO
CO
1 ^"^
co o o
1 i— O
O 1 —
§r~* X ^~*
r- X r- r—
CO LT> "d"
O LO
^_^
CO LO
1 1 ^"""^
O O VO
i— i~~ VO
vo vo
^3 X X **— •*
o
co cn o LO
• LO VO
00^—^-
CO i—
^~*.
CO LO
1 1 *^~^"
O O CO
vo r**»>
0 X X^'
•el-
co to vo cn
• LO r^
CO -VO
^_^
CO LO
1 1 t — •
o o o
^— f— ^f
O VO
o x x^--
CM CO 00 O
• ^- oo
r~ — '**•
CO i—
*-***
CO
o
^~
v^-*
00
^~*
VO
o
^~
•ta^X
vo
o^
**-*+
vo
o
r—
^_^
vo
V7>
^»— «,
CO
r-m
r—
^Ifc.^
co
o
f— •
^
o
•o
C71
CU
S-
O)
E
^^
c
3
^— ^
,
C
'i
cu
E
•4_>
(U *4-^
•<-> 01
*^~ «s •
c: LU c
•1— O •!-
^ *—--*— --*
^^^
S CJ C7)
o o ac
.. VI
•4-) T^ n E
c cu E
CU " S-
3 CU 3 "
r— 4-> -t-> CU
M- (O
C
o
CO
CO *•"•*
*r~ ^^*
E ^"^ W
CO CU CO
E T3
CM 3 "^
O f— -Q
00 O i—
4-*
c >, e
tfS ^ (J
i «/)
Q- X>
y -v^^
^D Q. Cn
•i- a. -*:
o
•M
(0
i.
-o
CD S-
CO 3
<+- 0
^-« x:
s- cu ^
x: c co
^. -i- C
.a x: o
r— O 4J
•~-* to
E o
S- -i-
x: s- i-
^*s. CU ^^
Cn -M CU
*>s c E
•i—
00
oo
V-5
-------
C 0)
(O i-
00
CM
I
O)
(O
O
O
•M
3 C
O -r-
l/) OO
to
•r- -0
s: cn
CU >O CD
E i- CM
-C CU r~
4-* >
•r- Cvl
in i—
CM
>}
fO
z:
CM
p*^
cn
r—
O
CM •« CJ
"Si" r--"
CM
>^
fO
s:
CM
pN,,
cn
r—
CJ
1— « CM
OO i— •
CM
>}
ro
2:
*• — *
•
£1
•r—
£=
^.-^
s_
CU (U
i J
3 4J
•z.
CU 4-^
C 4-> to
C? Q h-
in --^
r— ^""^ CD
i— o co
fi 10 •
CM in oo
«3- — CM
^_^ ^-^
CO
cn cn cn
r-. CM i—
r— pv.
1
, »
o^-^'cT
^ 00 •OO
"in c.>
co in oo
*1 CM
^-^ ^ x
CM
in cn cn
r— CM i—
CM r--
r—
cn ^->
^1" CO CO
co in co
O
in ^- co
cn in oo
CO CM
^— •* "w. ^
in
t~~ cn cn
O CM i—
i— r-.
*~~
?
o *~*
to cn
TJ :c
*»— ^t
X~-N •
c u_ c
•I— 0 -r-
E-
EO cn
oo u:
•• to
4-> T3 " E
c cu E
cu « s-
3 O) 3 «
i— 4-> 4J O)
<+- (0 10 S-
M- S- S- 3
cu cu to
2 Q. (/)
v o ^ ni
O i— CU S-
rtJ U- H- D-
00
, ^
co in *-^
1 1 VO
O O CM
i— i— VO
r— r—
CM X -X.
oo in in r^
• vo r^
c — -in
in oo
co in ^~-
1 1 CO
o o r-N
in '~ '~ r—
CM X X
i^
rj- 00 CO CM
CM — cn
in co
^-^
co in *-+
i i cn
o o co
CO *~ i—
»* X X — -
vo
CM CM «3" in
• «* cn
^f tw^^~
CO CM
^— ^
co in . — ^
i i i —
O O VO
i— i— CT>
in c—
cn x x —
cn
^t- in co «*
• CO •—
^-s JO
4J r—
c >i E -—^
>0 JQ O
•— OTB s-
Q. -D' -C
s: — ^>
•o Q- cn cn
•r- <\ .^ J>^
<
oo
cn
vo
o
vo
0>
10
en
co
co
o
to
O) O
_!_% ^i \
(O
s- o
•a t
cu •*->
«£ |
CU «
£Z CU**—^
•r- 4J S_
-C (O-C
o s--^
(O tO
E cu c
cr o
S- S- 4->
CU lO
E O
•r-
OO
V-6
-------
is designed to process approximately 12,000 scfm of gas at a 6% S02
concentration.
Table V-3 summarizes the emission test results from the ASARCO
smelter.
ASARCO, Hayden, Arizona
The ASARCO Hayden, Arizona, smelter is a custom copper smelter.
The smelter's copper converter single-absorption acid plant was tested
during the week of June 19, 1972. The test consisted of eight separate
runs using Method 8 for 40 CFR 60. Two of the test runs were aborted
due to malfunction of either the test equipment or the acid plant.
Test number 1 consisted of two samples, one for each orthogonal
axis. Their results were then combined to determine the emissions
rate for the test. In addition to the manual tests, continuous
S02 monitoring was performed at the site for two days. The continuous
monitoring test was intended to provide data for comparison with the
manual method and continuous monitoring experience for future tests.
No statistical analysis of the continuous monitoring data was performed.
There are five copper converters at the smelter; each converter
requires approximately 8 hours to process a batch of copper matte.
The gas flow to the acid plant from the converters is as high as
100,000 scfm, depending upon the number of converters in operation.
The gas stream to the acid plant has an SOo concentration of from 4 to
9 percent.
The converter emissions are controlled by a 750-tpd single-
absorption sulfuric acid plant designed by Chemiebau - Dr. A. Zieren
V-7
------- An error occurred while trying to OCR this image.
-------
GmbH of West Germany and built in 1972 by Rust Engineering, the U.S.
licensee of this company. The acid plant is designed to process
an inlet gas flow of up to 100,000 scfm at an S02 concentration of 45K.
The acid plant has a four-stage capability, but only three catalytic
stages were active during the test and one was blank.
Table V-4 summarizes the results of the Hayden emission tests.
Kennecott Copper Corporation, Garfield, Utah
The Kennecott Copper Corporation was tested during the week of
June 19, 1972. A total of twenty acid mist and S02 emissions test
were conducted on two of the five acid plants. Plant numbers 6 and 7
were tested with ten tests on each unit. Method 8 of 40 CFR 60
was used to perform the 20 tests. In addition, a continuous S02
monitor was placed into operation to record long-term emissions
from the number 7 acid plant.
All of the sulfur-laden gases from 9 converters are ducted
to 6 single-absorption add plants. There are 9 copper converters
at the plant. Their operations are phased to maintain a relatively
constant S02 concentration to the acid plants. The add plants are
designed to process a gas stream with a sulfur dioxide concentration
between 2 and 8%. The flow rate to the acid plant varied between
30,000 to 70,000 scfm depending upon the number of converters
in operation.
Acid plants numbers 6 and 7 were chosen for the tests because
they were the newest installations at the facility. Plant number 6
V-9
-------
COO-
+->
I— -O
CD -i-
EO
OO c£ CM
I —
i. i- en
0) •—
.--
i— a. s- cu
J2 O CO C
(O O > 3
I— c "~3
OO
O O
a:
S-
CU +->
C 4-> 10
3 —
o •*
CD •=!- en
i— CO U3
CM
CD * — -^-^
CD o r^
O O 00
« • •
*^ c^ r**.
Is- i — CVJ
S | •* "
+*_*t
CM 00
O *± 1^
CM
_
o ^^
r— *f
CM
O "~^
(/) CT>
•a 3:
^ I < e—
^ k^- W
•r-0 -r-
E ^— -^— "
E O O">
oo 3:
• • to
4-> T3 « E
c cu E
4-> — -*3-
^- LO
LO
I
CO O--^
i , — eD
O CO
i — X CM
*i- co
cn x oo^ —
cn
co cn co vo
• U3 CD
(— *-— -* r— —
LO t^
LO
1
CO O. — -
1 •— 0
O LO
r~ X f^
OO r—
CO X «*•> —
CM
CM i — 1 — O
• OO CO
cn — -co
CM CO
• •
in
o
in
in -^
£*-~- O
O) CU to
E -a • — -
CM3 ^^ L.
o i— .a ^.
CO O.— —
4J >^' £
c >x E "*^
rc) J3 u
1— •— * tfl i.
Q. TO -C
•s. -~*~ ~~~~
"O Q- CT> CD
•i— Q_ **-/ ^-
o
^c
V-10
-------
began operations in February 1967. It was designed by Parsons Co.
The plant was in the second month of its catalyst cleaning cycle
during the test program. The system has the capability of processing
up to 100,000 scfm of gas at a concentration of 2 to 8%. Plant number 7
commenced operation in September 1970. It was designed by Monsanto
Enviro-chem and was constructed by Leonard Construction Company. The
system was designed to handle the fluctuations of flow rate and S0«
concentration associated with converter operations. It can handle
S02 concentrations ranging between 2 and 8%. The number 7 unit was
in the last month of its catalyst cleaning cycle when the manual tests
were performed.
Tables V-5 and V-6 summarize the manual emissions test results
from the Kennecott acid plants numbers 6 and 7.
In addition to the manual emission tests performed at the Kennecott
smelter, a continuous monitoring test program was conducted between
September 15, 1972, and November 15, 1972, on the number 7 acid plant.
The purpose of this program was to gather long-term emission data
suitable for determining an averaging time which would effectively
mask fluctuations in acid plant outlet concentrations, and for evaluating
the long-term performance capabilities of single-absorption acid plants.
The emissions were recorded by a Dupont 460 Continuous S0£
Analyzer from September 15 to November 15, 1972. Section 4-1 of this
document discusses the results of that test.
V-T1
-------
f— CM
O CM i—
i— Ol hx r—
«— CM
1— (M
i— I--
f— CM
CM •—
0) r- •—
C CTl
Ol UD
CO1—- CM
i— OO
i— CM
r- CTl
-
Q. OJ O)
Q--f-> C
O S- 3
-
0) S-
C OJ
C CL
i— CVJ
r— CM
i— CM
I
+J l/> «
C TJ (K
O) -^-' S-
= OJ ^ _3 ^_^
4- t- E S^ U- 3 31
-^ o o £ aj c
O i— V> Q) CJ i- -^
C i— , —
00
••- > x **
-
oj CME
o o D
V-12
-------
i— CM
i— CM
CM i—
S_
A Q.
-------
Appendix VI
Analysis of Dual-Absorption Acid Plant Continuous S02
Monitoring Data
-------
Introduction
The dual-absorption acid plant for S02 control at the ASARCO copper
smelter at El Paso, Texas, was the first system of its type in the
domestic nonferrous smelting industry. The S02 emissions from this unit were
measured by EPA beginning May 17, 1973, and continuing through December 14, 1973.
The objective of the test was to characterize the $63 emissions
from a smelter using a control system of this type. The data were
analyzed to determine the control system efficiency and any conditions
which would cause high emissions. Finally, the emissions data were used
to examine realistic and achievable sulfur dioxide emission limitations
for nonferrous smelting operations which produce strong S02 streams.
The ASARCO smelter at El Paso, Texas, is a custom copper smelter
which produces 236 metric tons per day (260 TPD) of blister copper.
Approximately 365 metric tons per day (400 TPD) S02 are also produced
during the smelting process. The smelter operates three converters,
with two converters operating at essentially all times while the
third converter is in the pouring portion of its smelting cycle. This
type of cyclic operation typically permits a relatively constant, strong
(3-7%) S02 stream to be ducted to the control system.
The converter gases are controlled by the dual-absorption acid
plant which produces approximately 450 metric tons per day (500 TPD) of
sulfuric acid. The acid plant is designed to process an average inlet
concentration of 4% from an inlet concentration ranging between
2% to 10% S02 at an inlet flow rate of up to 100,000 cfm. The
VI-1
-------
autbthermal operating limit of the acid plant lies between 3.5 and 4%
$62. The system is provided with an automatic heater which permits
efficient operation of the acid plant down to an inlet S02 concentration
of approximately 2%. The catalyst renewal cycle of the acid plant is
designed to be approximately once every 2 years.
The monitoring instrumentation included a Dupont 460 S02 analyzer
for monitoring the outlet SC^ concentration, a Beckman inlet S02
concentration analyzer, and a Westinghouse E2B 4-channel tape
recorder which permitted simultaneous recording of time, inlet SC>2
concentration, outlet S02 concentration and inlet volumetric flow
rate. The Beckman inlet S02 was an integral part of the ASARCO
S02 control system which required modification to permit
recording of its output signal by the EPA recorders.
The accuracy of the outlet 862 monitoring instrumentation
was verified as outlined in the proposed EPA Method 12 of 40 CFR 60.
A total of nine manual Method B S02 tests, defined in 40 CFR 60, were
performed between July 9 and 12, 1973. Table VI-I shows the results
of the manual S02 measurements as determined by Method 8 and the
corresponding S02 readings as determined by the Dupont 460 S02
monitoring instrument.
The entire monitoring program covered a period of 5088 hours, or
212 days. During this time span, the acid plant was in operation
for a total of 190 days or 90% of the monitoring period. During
the same time span, the monitoring instrumentation was in operation
VI-2
-------
Table VI-1
Comparison of S02 Measurements Using
EPA Method 8 and the Dupont 460
S02 Analyzer
Test Results (ppm $03)
Date & Time Started EPA Method 8 Dupont Analyzer
7-9-73 (1617)
7-10-73 (1011)
7-10-73 (1418)
7-10-73 (1602)
7-10-73 (1745)
7-11-73 (0816)
7-11-73 (1000)
7-12-73 (1627)
7-12-73 (1805)
12.5
122.0
21.0
117.5
53.0
19.5
49.5
239.0
22.5
19.9
121.2
22.1
116.3
48.5
22.2
51.4
224.3
23.1
VI-3
-------
for 90% of the monitoring period. Taking into account periods When
both acid plant and monitoring instrumentation were inoperative,
data were collected during 86% of the time of the monitoring program.
The monitoring instrumentation recorded one reading for each parameter
monitored every 3 minutes. At the end of each 15-minute interval, an
average of the previous five readings was computed. The 15-minute
averages were used as the base data points for all subsequent computations
and analyses.
Validation of Data
To ensure that the recorded data were representative of "normal"
operating conditions, data validation criteria were established.
The acid plant operations log, the acid plant engineer's log, the
catalyst temperature charts, and the converter in/out charts were reviewed
to determine the operating state of the converter operations and
the acid plant. Periods during which the acid plant was not operating
and periods of excess emissions during startup were removed from the
compiled data. For purposes of analysis of the compiled data, all
other operating situations were considered normal.
During the course of the test program, the acid plant experienced
a number of shutdown and startup situations. The periods of acid plant
downtime 3asted for as little as 30 minutes to as long as 5 days.
It was observed from a general review of the data that the shorter
durations of downtime produced shorter periods of high emissions after
startup than the downtimes of longer duration. Therefore, each period
VI-4
-------
of downtime and startup was evaluated to derive a quantitative relationship
between the duration of the downtime and the duration of high emissions
after startup.
In developing an approximate relationship between the duration
of abnormal emissions and the duration of downtime, a family of curves
was prepared to show average emission vs time after startup based on
the data monitored. There were 25 startups during the monitoring period.
These were categorized into five groups depending upon downtime duration.
The curves represent the following downtime periods: 1.99 hours or less,
2 to 5.99 hours, 6 to 9.99 hours, 10 to 13.99 hours, and greater than
or equal to 14 hours. Each curve represents the following total
number of downtimes: 7 downtimes of 1.99 hours or less, 3 downtimes
of from 2 to 5.99 hours duration, 3 downtimes of from 6 to 9.99 hours
duration, 4 downtimes of from 10 to 13.99 hours duration,and 7 downtimes
of 14 hours or greater duration. Normal operation was considered
attained when the average emissions decreased to 500 ppm. Figure VI-I
shows the relationship between the downtime duration and the
emission rate immediately after startup.
The analysis of the curves indicates that downtimes of up to 1.99
hours did not cause excess emissions. Downtimes of greater than 14.99 hours,
however, typically created abnormal emissions for up to approximately
5 hours after startup. Other shutdown intervals resulted in normal
operation being attained after a period of time ranging between
the two previous extremes.
VI-5
-------
SHUTDOWN GREATER THAN 14 HR
0 1
2 3 4
TIME AFTER STARTUP (hrs )
Figure VI-1. Average emissions after startup.
VI-6
-------
It is realized that the exact duration of excess emissions during
startup will vary, because the time required to attain normal
operation depends to a major degree upon the skill of the acid
plant operator, his perception of the system's imbalance and his
response with corrective measures. Also, the time required to
attain normal operation is dependent upon the response time of the
acid plant system to any corrective actions initiated by the operator.
The curves of Figure VI-I indicate that there may be considerable
elapsed time after startup before the acid plant regains equilibrium
conditions. Based on these curves, data validation criteria were
developed for startup periods. Data points during the initial portions
of an acid plant startup were excluded from the analysis based on the
following criteria, to the nearest hour:
(a) For shutdowns of less than 2 hours, the first valid
datum point occurs immediately after startup.
(b) For shutdowns of 2 to 5.99 hours, the first valid
datum point occurs 3 hours after startup.
(c) For shutdowns of 6 to 9.99 hours, the first valid
datum point occurs 4 hours after startup.
(d) For shutdowns of 10 to 13.99 hours, the first valid
datum point occurs 4 hours after startup.
(e) For shutdowns of greater than 14 hours, the first valid
datum point occurs 5 hours after startup.
VI-7
-------
Discussion of the Data
With periods of acid plant downtime and the initial portion
of acid plant startup eliminated from the recorded data, the
remaining data constitute emissions from normal smelting and
acid plant operations. This includes periods of abnormally low
inlet concentration when all converters were out of the hoods for
short periods. These situations are common occurrences in copper
converter operations.
As previously discussed, the inlet S02 concentration to the acid
plant was measured at 3-minute intervals. The readings were then
averaged every 15 minutes to determine the 15-minute average base
data points. The inlet gas stream averaged 3.80 percent S02 for the
entire test period with a standard deviation of 1.64 percent S02.
The highest recorded 15-minute average inlet for the total monitoring
period was 9.19 percent S02.
An analysis of the distribution of the 15-minute inlet S02 readings
indicated that the acid plant processed gases of greater than the
minimum requirements for autothermal operation (3.5 percent) for only
approximately 55 percent of the time. Figures VI-2 and VI-3 show
the concentration distribution and the cumulative frequency distribution
of the inlet S02 concentrations recorded during the monitoring period.
An important factor to note is the percentage of time that the
acid plant operated at greater than 6 percent S02. The system
was processing gases of greater than 6 percent S02 only 11 percent
of the total operating time. This factor becomes important when
considering the general relationship of inlet S02 concentrations to
S02 emissions of this system as compared to other projected copper
VI-8
-------
u.
NoiivindOd
VI-9
-------
i i i i i i i i i r
I I I I I I I I I
o
CO
•o
o
0
0)
0)
rr-i >
CM1 *->
O CO
co —
I- C
^ £
o o
°I
CM
o
co
£
3
g>
L
r~
dO
«a- ro
-------
converter acid plants. Other nonferrous smelters typically produce
strong gas streams of consistently higher concentrations, on the
order of 6 to 9 percent SC^.
Catalyst Deterioration
The efficient operation of any acid plant is governed to a major
degree by the condition of the catalyst which aids the conversion
reaction of $03 to $03. As the catalyst is used, its condition
can deteriorate and thus decrease the control efficiency of the
system. This naturally results in increased emissions from the
acid plant. To ascertain any change in conversion efficiency
attributable to catalyst use, the change in efficiency was determined
for various time intervals over the total test period. The implied
assumption in this procedure was that any decrease in control
efficiency would be basically due to the decreased reactivity of
the catalyst.
The acid plant conversion efficiency was calculated using the
following definition:
Mass SO? converted
Efficiency (E) = Mass S02 available
Adopting the ideal gas law for S02, the previous definition can
be represented by the equation:
E = (1 - c— ) (1 + Cout * C2out * - - - + Cnout)
C-jn = S02 concentration entering the acid plant.
Cout = S02 concentration leaving the acid plant.
VI-11
-------
The acid plant commenced operation in December 1972. Between
May 1973 and December 1973, the acid plant was monitored while operating
for approximately 171 days, or approximately 86 percent of the time.
At the end of the monitoring program, the acid plant had been in
operation a total of 336 days.
The normal cleaning cycle for the acid plant catalyst, based on
the manufacturer's design, is two years. Thus, the system was
monitored during the second quarter of its normal catalyst cleaning
cycle. Due to the failure of parts of the gas precleaning system
to operate properly, however, the catalyst deterioration rate was
accelerated and the acid plant catalyst was screened during March 1974.
Based on this information, the catalyst renewal cycle therefore
covered a period of 1.2 years, and the acid plant was considered
to have been monitored during the second and third quarters of
its catalyst cleaning cycle.
One least squares regression analysis of the change in efficiency
with usage covers the total test period from May 17, 1973, through
December 14, 1973. Similarly, second and third analyses of the
change in efficiency w:'oh time were also made and included the last
two months and the last month of the monitoring period, respectively.
A review of the three results indicates that the acid plant's
efficiency remained essentially constant at an average of greater
than 99.70 percent during the total test program. The respective
changes in efficiency within the observed periods indicated by
the three analyses were 0.20 x 10"7, 5.6 x 10'7, and 8.7 x 10-7
VI-12
-------
percent per day. The minimum efficiencies from these changes in
efficiency were 99.750%, 99.643% and 99.688%, respectively. Thus,
neither within a given interval nor between one reporting interval
and another did the analysis show sufficient changes in efficiency
to indicate a significant change in the condition of the catalyst.
Effect of Inlet SO? Concentration on Emissions
The most important aspect of the inlet S02 concentration is
its effect on acid plant operating efficiency and the resulting
outlet S02 concentration. To ascertain the effects of varying inlet
S02 concentrations on the resulting outlet S02 concentrations, all
of the simultaneous 15-minute inlet and outlet concentration data
were used to develop a least squares straight line. The results of
this analysis indicated there is a direct linear relationship between
inlet and the resulting outlet. The correlation coefficient of
the analysis was calculated to be 0.413 and determined to be significant
enough to warrant a conclusion of linearity. Figure VI-4 shows the
graph of the least squares line and its standard error.
The inlet S02 concentrations experienced during this test were
somewhat lower than the concentrations of 5 to 6 percent which are
achievable from typical copper converter operations. With an average
of 3.8 percent S02 and a standard deviation of 1.64 percent S02,
approximately 68 percent of the readings were between 2.2 and 5.4 percent
S02, indicating that the inlet concentrations are biased low and thus
result in lower outlet concentrations. The fact that the acid
plant inlet concentration was typically low indicates that the typical
VI-13
-------
350,O
300.0
250.0
LU
150.0
100.0
50.0
i i i i r
i i i i r
III!
II i I I
567
INLET [%S02]
9 10 11 12
Figure VI-4. Outlet S02 concentration versus inlet S02 concentration.
VI-14
-------
outlet concentration was lower than that expected from other similar
acid plants operating at a higher average inlet concentration. This
factor must be taken into account when determining emissions limits
for other smelting operations, based on data from this test.
An inlet concentration of 9 percent is approximately the maximum
inlet S02 concentration that can be processed by most modern
dual-stage acid plants. Figure VI-4 is significant, therefore,
when predicting the expected emissions from a smelter generating
an inlet gas stream within the observed range of this test (0.02 to 9.16%
$02). It shows that the average outlet concentration increases
approximately 50 ppm per 1 percent increase in inlet concentration
above 3.8 percent. For instance, when the average inlet concentration
to the acid plant was 9 percent S02, the average emission rate
indicated from the test was approximately 3 times the emission
rate obtained at 3.8 percent inlet S02. This increase is basically
due to increased inlet concentration at a constant conversion efficiency.
Results of the Test Program
The results of the test program indicated that during normal
operations the average emissions, based on 15-minute readings,
ranged between 10 and 2920 ppm. Approximately 90 percent of these
values, however, were below 250 ppm and well below the typical
manufacturer's guaranteed emission rate of 500 ppm.
There were, however, periods of relatively high emissions, even
when averaged over six-hour periods, which could not be attributed
to malfunctions, startups or shutdowns from analysis of the data
recorded during these periods. It was thought that these periods
VI-15
-------
might be caused by relatively high inlet concentrations, resulting
in a corresponding increase in outlet concentrations. In order
to examine this possibility, 6-hour averages of 400 ppm or
greater were located in the data base, and the twenty-four 15-minute
inlet concentration readings which made up the 6-hour averages were
recorded. The concentration frequency distributions of these
inlet readings were then compared with the inlet concentration frequency
distribution for the entire monitoring period. In general, the
individual distributions did not vary significantly enough from the
composite for the entire monitoring period to indicate that the
excursions occurred during periods of unusually high or during
abnormal inlet concentration conditions. The catalyst converter
temperatures and inlet gas flow rates were also reviewed, but no abnormalities
were noted in these parameters.
Since the periods of relatively high emissions were not caused
by abnormal inlet gas conditions or by abnormal operation of the acid
plant system, the compiled data were averaged over various time intervals
ranging from 1 to 10 hours in order to examine the effect of averaging
time on damping of normal excursions. As a result, the effects of
normal short-term excursions were spread over successively longer
periods of time. Table VI-2 show;; a matrix, to the nearest 0.05 percent,
of the percentages of the total readings which exceeded given concen-
trations for various averaging intervals.
It can be seen from Table VI-2 that as the averaging time for
a given concentration level increases, the percentage of excursions
VI-16
-------
"g"
CO Q_
£ *^^
•r-*
1— CO
C
en o
5) re
re s-
S- •(->
CO C
> co
T-
co cs
1
; -u
c re
O
•r- CO
4-> C
re o
S- •!-
+J CO
c s-
CD
u re
CO •!->
<«- c
H- CO
LiJ O
S-
01 CO
-c CL.
1—
CO
-C
CM
1 £=
1-1 O
CO
re
.
x e
re Q-
s: Q.
o
in
r-.
o
o
r--
o
in
10
o
o
10
o
in
in
o
o
in
o
in
o
o
o
in
CO
o
o
CO
o
CM
o
o
CM
o
m
r—
CO
01
C
• r—
=fc= "O
re
CO
a:
Si
-------
above that concentration level tends to converge to zero. For example,
Table VI-2 indicates that from 20 to 15 percent of the recorded values
exceeded 150 ppm, depending on the averaging intervals between 1
and 10 hours.
Similarly, in Table VI-2 an increase in the concentration
level for a given averaging time will also cause the matrix to converge
rapidly to a small value. For example, observing the 6-hour
averaging interval, there is a 20$ excursion rate at the 150 ppm
level. Increasing the concentration level to 300 ppm decreases the
excursion rate to 2.45 percent; increasing the concentration level
to 750 ppm decreases the excursion rate to 0.05 percent.
Based on the results of Table VI-2,as either the averaging
time increases, the concentration level increases, or both increase,
the percentage of excursions tends to converge toward a small value
in the matrix.
Conclusions
As previously indicated, the typical manufacturer's guarantee
for a dual-stage acid plant is 500 ppm, based on a 5 to 6 percent
average inlet S02 concentration. The results of the test, however,
indicated that the test was carried out at a 3.8 percent average
inlet concentration, somewhat lower than the average inlet concentration
from typical copper converting operations. The test results also
indicate that there is a direct linear relationship between inlet
S02 concentrations and outlet S02 concentrations; the inlet concen-
trations increase proportionally with outlet concentrations. Therefore,
VI-18
-------
since the Inlet concentration was somewhat lower than normal, the
resulting outlet concentration was considered lower than that from
typical copper smelters.
Since the manufacturer's guarantee of 500 ppm is based on a 5 to
6 percent inlet 862 concentration into a typical smelter converter
acid plant, the equivalent SOg concentration for the ASARCO
acid plant during the test period was 400 ppm. This is due to
the typically lower inlet concentrations.
As discussed in Appendix V, an appropriate averaging time
for masking outlet concentration fluctuations from single-stage
acid plants was determined to be 6 hours. The test of the ASARCO
plant indicates that a 6-hour averaging time is also sufficient to
mask fluctuations from a dual-absorption acid plant. The results
show that an emission rate of 400 ppm for a 6-hour averaging time
would result in 1.20 percent excursions.
Though the results of this test program indicate that a reasonable
emissions limit equivalent to the vendor's guarantee (400 ppm) would
result in only 1.20 percent violation rate, the effects of higher
inlet S02 concentrations at other smelting operations and acid
plant catalyst deterioration must be taken into account. To account
for situations of increased emissions due to higher inlet concentrations
up to 9 percent, the results of Table VI-2 require prorating upward
a maximum of 200 ppm.
The results of this test were not conclusive as to the characteristics
of increased emissions due to catalyst deterioration since no deterioration
was observed during this test. Discussions with the designers of the
VI-19
-------
ASARCO acid plant indicated that up to a 10 percent increase in
emissions was expected before renewal of the catalyst. This factor,
therefore, has to be taken into account when predicting the expected
emissions from a system of this type. Based on the previous factors,
the results of Table VI-2 were prorated upward to take higher inlet
concentration and deterioration into account.
Table VI-3 shows an acid plant operating at an inlet of as high
as 9 percent and taking catalyst deterioration into account. From
Table VI-3 it can be seen that an acid plant processing the maximum
expected inlet concentration could be expected to maintain an
emisslion rate of 650 ppm with only a 1.20 percent excursion rate.
In general, however, a new source performance standard set at the
650 ppm level and a 6-hour averaging time would result in a probable
excursion rate of less than 1.20 percent. The general provisions
of new source performance standards (39 FR 9308) specify that each
performance test for the purpose of compliance shall consist of
the arithmetic mean of the results; from three separate runs. To
determine the number of times that the ASARCO acid plant exceeded
the 400 ppm level (equivalent to 650 ppm in Table VI-3), the
recorded data from the test program were reviewed. Each 6-hour
average of 400 ppm or greater was considered an excursion. Readings
for 24 hours both before and after the violation were reviewed to
determine whether the average of any two readings together with the
excursion would exceed 400 ppm. The three 6-hour averaging periods
were chosen so that none of the periods overlapped. The results
VI-20
-------
o e QJ
CO
D_
01
XI
to
X
o
o
o
un
ID
O
O
o
LTJ
o
o
na
S-
01
LT)
CM
O
CM
O>
3 CN
O O
r--
t^
CTl
LT)
«*
O
o
01
o
o
CM
LO
I—
O
O
O
c
o
o
o
CM
O) CM
OlO
(O CO
cu +->
> 0>
IO i—
O O
CD cr>
en c
CO •!-
+-> -o
C O)
cu
-------
indicate that, of 48 recorded readings greater than 400 ppm during
the entire monitoring period, only six result in averages of three
runs greater than 400 ppm. From this evaluation, the probable
percentage of 6-hour averages in excess of 650 ppm, based on a
9% S02 inlet stream, would be approximately 0.15 percent.
VI-22
-------
Appendix VII
Results of Parti oil ate Tests Performed at
Primary and Secondary Nonferrous Smelting Industries
-------
-------
Particulate Emission Test Results
Introduction
This section presents the data used to develop the proposed
particulate standards for primary lead and zinc smelters. The
affected facilities are zinc sintering machines, lead blast
furnaces, lead dross reverberatory furnaces and lead sintering
machine discharge ends.
Particulate emissions from one primary lead smelter were
measured. Due to the limited number of suitable testing sites
in the primary industries, other data were considered from the
secondary lead smelting and refining industry, and the secondary
brass and bronze ingot production industry. In these instances,
it was concluded that the emission control devices tested and the
characteristics of the particulates and effluent gases were similar
to those of the primary industries.
Particulate matter emissions were determined according to EPA
Method 5 of 40 CFR 60, December 23, 1971 (36 FR 24888). The data
summarized correspond to the front half catch (probe and filter
cfctch) of the emissions testing train.
Discussion
One primary lead smelter was tested; the control device was a
baghouse. The remaining data are from previous EPA test programs in
the secondary nonferrous smelting industry. Three secondary lead
smelters were tested, all of which use baghouses to control emissions.
VII-1
-------
One of these facilities controls blast furnace emissions; two control
reverberatory furnace emissions. Two brass and bronze smelters
were tested, both of which use baghouses to control emissions.
Both plants use reverberatory furnaces to melt scrap materials.
Table VII-1 summarizes the results of these tests.
ASARCO Primary Lead Smelter. Glover. Missouri
The blast furnace and dross reverberatory furnace baghouse
at the ASARCO primary lead smelter in Glover, Missouri, was
tested on July 19-20 and 23, 1973. The smelter has a design capacity
of 81,800 metric tons (90,000 tons) of lead per year and started
production in 1968.
The blast furnace is an Australian step jacket design with a
nominal capacity of 273 metric tons (300 tons) of lead bullion per
day. The furnace is 7.6 meters (8.3 yards) long, 1.5 meters
(1.64 yards) wide at the lower tuyeres, and 3.0 meters (3.28 yards)
wide at the upper tuyeres. A blower provides up to 510 cubic meters
per minute (18,000 ft3/min) of air at 0.26 kg/cm2 (0.76 lb/in2) pressure
to the furnace. The top of the furnace, where charging takes place
and effluent gases are ducted to the control system, is of typical
thimble-top design.
Charge materials for the furnace consist of coarse sinter,
iron, coke, and caustic skims. Charging usually occurs 17-18 times
per shift.
Effluent gases from the blast furnace, swivel vibrator (transfer
of sinter to storage bins), Ross classifying rolls, dross kettles,
VII-2
-------
•1—
c
zo
0
•r-
-o
C- — •
ro v-
o
CU CO
.a -a
o ~~-
i. i~
a. a
i
e
CO O
c co
o -a
•r— **^.
CO CJ
CO £
•r—
^-^
oo
o
co|o
o
o
n|d
r—
10
•
en
x~^
CO
o
o
«"~^s
^^
o
o
cold
o
•
vo
r—
*~*t
LD
o
o
cu
s
(O
0)
CO
c
o
co
CO
cu
+->
ro
3
u
i.
ro
a.
c>-
o
>>
3
00
CM|O CM|O CM|O
CM|O
CU
13
O
4J
(O
O.
oo
o
•id
co
CO
CO
o
o
-id
co
oo
o
o
in
uo
o
o
r-IO ^|,
CM
o
o
10
o
o
-id
oo
en
in
•r-
i.
C
O
•r-
•M
ro
o
0
_i
3
» 0
i- CO
CU CO
o £
5
« ro
CO •!—
ZJ CD
JD S-
E o
3 CU
i— tS
0
o
*l
o
o ro
CO ••-
•i- C
u s-
c: o
ro **—
S- M-
U. i—
ro
sz o
ro
00
ro
•r—
n ^_
>> O
L. C)_
-f-> *r~
CO , —
zi ro
T3 O
C
h-4
CO
•1—
O
r—
I — i
A
_^
O
o
ej
o
E:
CO
•^
" O
0 C
ro .—
O i—
•i— i — i
.c:
0
S-
ro s-
f£
a. cu
i oo
O -o
o ro
o; cu
•o
ro
cu
1-1 S-
ro
d" c
o o
_i o
LU > 0)
S- N
ro c
ie
O 00
o
ro
i
CO
O co
c_> ro
cc s-
cC CO
OO
o ro
c cu
o s-
u ro
+j -O
cu c
E o
cu o
3 CU
o-oo
CO
cu -o
•i- ro
i. cu
co
T3 S-
c ro
i—i ^3
• o
_I O
• cu
^. oo
CO
c cu
O N
00 C
o
o3 &-
03
> C
ro ro
_i
CO
• co
_i ro
• s-
CC OQ
VII-3
-------
Roy tapper, slag granulator, lead tap, slag taps and feed hopper
drop points are exhausted to the blast furnace baghouse control
system. The baghouse control system consists of a humidifying
chamber, fresh air inlet, line addition system, and a baghouse.
The ASARCO-designed baghouse is enclosed in a concrete structure
containing 6 compartments and is of the pressure type. Each compartment
contains 204 wool bags. The inlet flow rate to the baghouse is
3710 m3/min (131,000 acfm) at 58.3°C (137°F). Lime is added between
th« water spray chamber and the baghouse to aid in collection efficiency
and to retard ignition of the collected dust.
The filter bags are cleaned by mechanical vibration. The compartment
dampers remain closed for approximately 20 seconds after cleaning to
allow particulates to settle. Compartments are cleaned on a rotation
basis when the pressure drop across the baghouse exceeds 3 inches of
water. When cleaning one compartment fails to sufficiently lower the
pressure drop (generally to below 2 inches of water), the next
compartment in sequence is cleaned. During the testing program,
it was observed that two compartments were generally cleaned in
sequence during one cleaning cycle.
The smelter was operated at capacity during testing. Production
rates ranged from 12.5 to 12.6 metric tons (13.8-13.9 tons) of lead
bullion per hour during the tests.
Particulate sampling was conducted simultaneously on the three
stacks from the baghouse. Table VII-2 summarizes the results of these
VII-4
-------
in
CM
^»
^— -»
00
CO
r-, co
1 00 i—
CO CO CM
CM i —
i in
CM
o
CD """""^
o oo
A CO
CO r—
*st" *— ^
r—
— -^J-
O i—
CO CO
CM
**
^••^•S
0
CD *****
o co
•* r**.
VO r—
^J- ^— - *
r-.
^CVJ
o ^r
co
*•—• •»-•— »
f— ^,0 -— — ox— ^>
**• 1— r-*. cvj
f— i— • ^i"
o o r*. •
, . r__ ,_
CD CD *»— ^*»— "
^"^«* «rf-
i — ID O ^O
• • • •
CM CO OO O
CO CM
*—•**—»
r*^ co ^~**
Is** ^" *•*"-• 00
i — r— CO !*•*•
o o • •
• • CM •—
O CD CM
*— ^»»— *s^_x
r—
«*• CO i — OO
o co o o
"3- CO i —
CM
1 — 1
1 — 1
^»
Ol
o:
01
CO
0
J-
Q •<-
S-
TJ 3
C O
O
4-> i —
to
CO
1
^_
Ol
E
oo
TD
to
O)
_1
>,
(O
c
•p—
S-
Q-
o
o
^£
oo
^^
01
•t—
c
Z3
JZ
01
•r"
"cn
c
UJ
CO
4->
E
"^
t_)
C_
1 \
O)
1
CO
4->
"3
co
O)
o:
M-
o
>>
S-
tO
E
3
OO
^-^
00
CO
1^ CO
1 00 i—
CM O CM
CM i —
i in
1^.
CM
*— «*
en
CO
r^, co
1 00 •—
r— en CM — -
^— f—
1 CO
r--.
CM
^— ^
t^
c~
-^^^
CO
« c
O) O
to **-^
S-
i.
C. -C
c o -^
•r- -I- 01
E 4-> C
0 0
" 3 4->
O) T3
E 00
•r- i. •!-
•(-> Q. i.
-O
OJ O
4-> 0
• • to
4-> S- n
C QJ
CV ^ L>
3 O 3
r— i— •!->
4- C|- IO
<4- S-
O) r— O)
fO O.
^ +J E
O O O)
(01—1—
4_>
CO
x^-^^—^
fx^, ^_
CD r*"- "^~^"^~^*
oo vo r*^ vo
O 0 -00
O O CO •
. . r- O
CO CD ^— **— *•
^— x««_--
co en
^~ co oo co
• • • •
oo in "st o
i— i —
*•— -.^-N
o en- — " — •
r-». co CM o
i—i— -co
000 •
• • CM r—
CO o- -— '
^— *^— ^
1 — CO
en co i— r-.
• • • •
oo i— en o
CO CO
-!->
O
3
"O * — ^
JC O +->
O S- O
•••(-> Q. 3
co to *^** ^D
c: u *•- <»- o
O O O S-
•r- s_ co*— « a.
CO QJ "O Cj_ ,. — . c
01 -l-> *^ O
E -i- Oi"^.1"^
O) c,_v_^ s_ _Q o C
Oil •!- O
O) "O E — ' — - S- +>
-M C O 4->
to to coco t. QJ ja
r- -0 E -C Er-^
O -O Ol Ol O^ Ol
•r- 0 E E -* J*
4-> S-
s- a.
to
a.
VII-5
-------
tests. The data presented are averages of the simultaneous tests
performed on each stack.
SELCO Secondary Lead Smelter, Columbus, Georgia
The SELCO secondary lead smelter at Columbus, Georgia, was
tested on August 6-8, 1973. The plant processes approximately 910 metric
tons (1000 tons) of lead per month. About 70 percent of total production
is hard lead, an alloy containing 95-98% lead. The remaining 30 percent
of production is essentially pure or soft lead.
Two 1.28-meter (42-inch) inside diameter blast furnaces operate
24 hours per day, 5 days per week, 50 weeks per year. Tuyere air,
enriched to approximately 23 percent oxygen, is fed at a rate of
approximately 19.8 dscm/min (700 scfm) to each furnace. Charge
materials to the furnaces include lead scrap, coke, slag, and other
fluxing agents. Lead is continuously tapped from the bottom
of the furnaces. Normal production from each furnace averages 1.2
metric tons (1.1 tons) per hour. During the testing periods,
production averaged between 0.90 metric tons/hr (0.99 tons/hr) to
1.1 metric tons/hr (1.21 tons/hr).
Combustion gases are exhausted through a stack at the top of
each furnace. The gas stream from each furnace is directed to
a separate afterburner, cooling system, and baghouse. The gases
are cooled with a water spray and dilution air.
One of the two baghouses operated by the smelter was tested.
The tested baghouse has 5 compartments, each containing 238 acrylic
bags that are replaced on a 9-month schedule. The design capacity of the
baghouse is 396 dscm/min (14,000 scfm). The filter bags are cleaned
VII-6
-------
by mechanical vibrators activated once per hour for a total cleaning
time of 6.5 to 8 minutes per compartment. Bag-shaking takes 60-90 seconds
per compartment. The gas stream is exhausted to the atmosphere through
a 36.5-meter (100-foot) stack.
Four runs were conducted during the testing period. Table VII-3
summarizes the results of these tests.
ASARCO Secondary Brass and Bronze Smelter, San Francisco, California
The ASARCO secondary brass and bronze plant at San Francisco,
California, was source-tested on November 30 to December 3, 1971. The
plant produces brass and bronze ingots by melting selected scrap
and virgin materials in furnaces, refining the molten mixture, and
casting the refined alloy into ingots.
The plant operates two oil-fired 18.2-metric-ton (20-ton) rotating
reverberatory furnaces designed by ASARCO. The charge to the furnace
includes recycled wire, discarded radiators, various other forms of
scrap, and fluxes. The effluent from the two furnaces is discharged into
a baghouse designed by ASARCO. The baghouse is a closed-pressure type
which is cleaned by mechanical shaking. The baghouse has seven
compartments, each containing 33 bags. Exhaust gases are forced
through the baghouse by a 935 m3/min (33,000 cfm) fan. A manifold
duct and breaching system direct the filtered gas to a 91.4-meter
(300-foot) high stack which vents to the atmosphere.
Testing times were longer than two hours due to the large
number of traverse points required by the flow pattern in the
breaching system. Table VII-4 summarizes the test results.
VH-7
-------
CO
3
O
(O
CQ
(O
3
CD
C
LJJ
CO
^ +»
oo
n)
r— ro oo
CQ T- 4->
CD-r-
S- S- C
CO O =3
' CO
CO
(O
i— CD O
OO 00 4J
3 CO
-o -a is
re E
CO 3 I
"o oo
>>CJ 4J
(O 3
"O 00
C. CO
O OL
CO «»-
oo o
o
o
CO
CO
CD
^c
00
f^.
1
«* 00
1 1
00
CO
^.
1
co oo
00
oo
r*^
i
CM l*~
i
00
CO
i
i— V£>
I
CO
CO
C 4-»
3 (O
C£. 0
in
CO
r—
0
CM
0
CO
o
CM
^—
o
CM
.
c
E
ft
CO
E
^_>
+J
00
CO
h-
^— •*
r-*-
r— •
•
r—
*»— "
OO
o
•
^— N
r™~
CM
•
^~
«*_^
f~ ,
•
.»••— x
^—
CM
^~
*^-*'
,
•
"
^••N
CM
0
•
^~
•-— '
CO
a*
•
o
en
en
o
^~*
0
en
.
o
„
CO
+JI
S-
c
o
•r—
+J
o
^
13
O
S-
o
T3
re
-1
*— ^*— »
o en
co en
CM i—
«^^>
00
in •
00 CM
CM en
*"^*-~^
o in
CO O
CO CM
CO * —
' 0
vo .
CO «3
CM cn
^— ^^— «*
o oo
in o
O CM
en — -
*^*
o
in 06
CM en
x— *.*—•*
0 i—
i— O
O CM
^_^
en
in •
in co
CM en
CD <*~^
O CM
in oo
CD-d-
*. ^ ^>
.
i— 00
en oo
CO
1"
^— . o
J- 00
.c -a
c e u_
O T- O
•4-> E •> — -
"^ E 0
S- U o
JZ .-00
^*x. 4-> "O •*
00 c CO
c: eo " i-
o 3 eo 3
(^ (^ (^
0 •
. • CD CD
o o — • — -
•*— ^*—^
1*- CO
i— «* CM i—
.— 0 r- l—
00 UD O CD
*—^* — « LO CM
CM i— CO i—
0 O •— r-
O O • «
. .00
0 0 —
i — in
^j- O *o in
CO CM O O
•d- CO O CD
CM i — CM CD
0 O CO r-
0 O r- •
... 0
O 0 0
in
o r^ vo in
en oo o o
* • • •
CO CM O O
o en
^-«— CO VO
co vo in in
o o • «
0 O 0 O
C3 CD
•»•— • '»— • "CO CO
VO CO
CM CO CM CM
P^ CM O O
r— r—
__^.^-
co CM f~- r-
O O CM CM
o o • •
. • o o
o o — - — '
m cn
i — CO CM CO
O CO i— i—
i^ in o o
-P
o
-C 3
O -O'-»
.. ^J O 4J
oo OO *~* O.
•1-1 — -o 4- *-* c:
E -r- ~~^ O S- O <»-
CO H- S- (O -C •»-> O
co -&-~-^ i- xs o c
•»-> C CDi — -r- O
«B ic E> — *— • S- +*
3 CO OOCO S- CO .Q
O -Q TO E *~ E r™~
••- o -^-^-^^^ — -
-M ^- CD CD CD CD
s- a. E e •* -^
re
Q.
-------
Ol
o>
(C CO ^-
fc. CM CO
O) CO VO
00
CO
or-
i— CO
•* |"~*
CO
co
—-co
*
r-^oo
co in
01
in vo
co o o vo
00 10 r- O
1
Ol
u
10
j-
£
o
IO
I
I
s
I/I
•0 O>
-
O
it-
l-» O
I VO O CM
co co in *t —
i CM in
CM CO
""" 00
CM
r*I oo
I f*« 00 t~
CM i— ^- CM—'
CM in
to
Ol
Oil— •!-
N lt5 C
§0=}
i~ » O
CO O f-
Z2 o i-
to -o co •»->
h- C-r- CO
CO Ci-
10 3
>»OO CO
S. Ol
(O OL
-o
§ •&
s »
oo s-
en co
co«
CO
oo in
in in
oo
o.—•
o in
o> co
co
»—CM
§U>
co in
o» 10 oo vo
CM o r— o
CM CM
00 vO i— O
o
•
00
1 O iO CO *
co CM in
I
CO'*-'
CM
CM
O» CM
O VO
00
COi— O O
o
C£
<:
oo
C C
0) 4-> -4-> O
C 4-> M I
3 to 01 CD n
a: OH- £ i-i
OO
VII-9
-------
Quemetco, Incorporated,Secondary Lead Smelter, Industry, California
The Quemetco secondary lead smelter at Industry, California, was
source-tested on January 26 and 27, 1972. A reverberatory furnace
is used to melt lead scrap from manufacturers, scrap batteries, and
various lead oxide drosses and dusts.
The reverberatory furnace is fired with natural gas at a rate
of 7.5 m3/min (265 cfm). The hearth is about 17.6 meters (25 feet)
long and 2.4 meters (8 feet) wide, with the roof at about 0.9 meter
(3 feet) above the melt. The furnace is batch-charged each 8-hr
shift in 454 kg (1000 pound) increments. The gas to the furnace is
turned off 30 minutes per shift to allow for dust removal from the
ductwork, and the dust is immediately charged back to the furnace.
Air is drawn into the furnace through the two sight and stirring
ports on the feed end of the furnace, and through the feed port and
slag port. Excess air is necessary to burn the volatiles in the
battery cases.
Exhaust gas from the reverberatory furnace passes through a
water spray chamber and cooling tower, and then to a baghouse. The
baghouse contains seven sections with a total of 1100 bags, and is
insulated to prevent water condensation. The flow rate to the
baghouse is 425 m-Vmin (15,000 cfm). The bags are cleaned by
mechanical shaking, and the cleaning cycle time is 50 minutes.
Three particulate tests were conducted. Each sampling period
encompasses periods of loading, meltdown, slag tapping, and lead
tapping. Process operation during testing was typical of normal
operation. Table VII-5 summarizes the test results.
VII-10
-------
CU
en
s-
d)
o CM
CM
O 00
f-» VO
in
r-.
oo
CU
co
3
O
CD
o in
CM r^
CM o>
o r*-.
00 VO O O
(O
I
I
CO
C
CM i—
r-
i o CM
CM VO CM—'
CM i—
I VT>
o
o
CM
to
co
o co
co r---
CU
S- "v-
cu >> s-
i— -P 0)
QJ lA ?*"
S 00 TJ I
CO CO
i— VO VO CO
«3- CM i— O
vo in
CM i—
r-.
i o CM
r— VO CM
CM i—
o vo
<£> VO
en oo o o
o
sz
o
co
O
3
o
o
0)
o-
cu o
4J 4J
CO
S-
• c -c
c o ^
•i- -r- CO
E 4J C
O O
» 3 •!->
cu -o
E O O
•J3 a. s-
•iJ
CU 4-> T3 CO
C 4-> CO « £
3 19 CU CU
^
o
i CO
i T3
o
c
cu
O)
(J i
(O
oo
CU
4J
(O
S-
cu
s-
3
+J
(O
S-
CU
CU
CO CU
to ^j
Cl3
co ta
CO __
o i- o
„, -^ CO ^^ Q_
.^ r- p Cj- ^-. C
E '•- >~ O S- O <4-
cu <*- t. o
CU TD
-!-> C
3 cu
O -Q
s- J3 o c:
COi i- O
—.—- $_ +J
-|J S. O! CO CO CO
S- O. E E -*^
(O
0.
vn-n
-------
N.L. Industries Secondary Lead Smelter, McCook, Illinois
The N.L. Industries secondary lead smelter in McCook, Illinois,
was source-tested on February 9 and 10, 1972. Lead scrap is received
as discarded batteries with the cases removed. The plant processes the
battery plates into soft lead ingots.
The scrap lead is melted in a natural-gas-fired reverberatory
furnace which is charged at regular intervals. The charge to the
furnace includes lead oxide dust in addition to the lead batter plates.
The hearth is about 7.6 meters (25 feet) long and 2.4 meters (8 feet)
wide with the roof about 0.9 meters (3 feet) above the melt. The natural
gas burners operate at full capacity except for brief morning periods
during which the ductwork is cleaned. The gas firing rate is 13.6 m-Vmin
(480 cfm). The furnace is operated under a slight draft to prevent
fugitive dust emissions. The charge increments are approximately
600-700 pounds. The feed is loaded into a hopper over the feed ram
with a front loader; the ram operates continuously. The feed rate is
controlled by the buildup of unmet ted feed in the front of the furnace.
The exhaust gases from the reverberatory furnace pass through a
brick flue, a cooling tower, three water-cooled cyclones, and then to
a baghouse. The baghouse has four sections of 120 bags per section.
Design air flow rate is 850 m3/min (30,000 cfm). Bag shaking time
is 8 minutes per half hour, with no shaking during the last 22 minutes
of a half-hour cycle. Each section is cleaned for 2 minutes. The
design collection efficiency is 99.9%.
VII-12
-------
Three runs were conducted during the testing period, and the process
was operating normally during testing. Table VII-6 summarizes the
test results.
R. L. Lavin and Sons Secondary Brass and Bronze Smelter. Chicago. Illinois
The R. L. Lavin and Sons secondary brass and bronze smelter at
Chicago, Illinois, was source-tested on January 1-5, 1972. The facility
processes brass scrap in a reverberatory furnace to produce ingots.
The reverberatory furnace is stationary and fired by gas. The
furnace capacity is approximately 91 metric tons (100 tons) for brass.
Air lancing is used to remove the iron from the melt. Exhaust gases
pass from the fur-iace directly through a 27-37 meters (30-40 yards)
refractory flue which serves as an afterburner. From that section of
the flue, the gases pass through approximately 9.1 meters (30 feet) of
water jacketed ductwork, and through a series of U-tube heat exchange
elements upstream from a baghouse. The U-tubes are approximately
9.1 meters (30 feet) high and are used to achieve the desired baghouse
inlet temperature [71°C (160°F)-107°C(225°F)]. The tubes permit
temperature control without the use of water sprays.
The baghouse has 36 compartments with 25 bags per compartment.
Two suction fans draw approximately 1250 m3/min (44,000 cfm) of gas
through the baghouse. The baghouse uses electrically timed mechanical
shakers for cleaning. The 36 compartments are divided into 3 separate
systems for cleaning. The total cleaning time per system is 30 minutes.
Each compartment shakes for 60 seconds, and the lapsed time between
shaking of successive compartments within a system is 90 seconds.
VII-13
-------
to
1— 1
f-*
>
£
0)
0 ^
(O CO
C 4->
i. •!-
3 C
U. Z3
>> -c
i- CO
O •!-
•P r-
«3 CT>
S- C
O) M-l
f^ ^-^
S-
CO CO
> CO •!->
O) T- •!-
o: o c
C =3
S- -r-
O) r— O
+J r- ••-
i— i— i i-
J4J
•> cy
\x y
O
TJ O 1
OS O
CO •> "3
S- CO
tO O)
TD Qi
C
0 «4-
o o
0)
oo >>
S.
CO TO
O) E
il 3
•M CO
CO
3
T3
C
1— I
•
_J
•
Z
O) 00
o^ •
10 o oo
i- in — -
OJ r—
> rl-
^C •
CO
X~*s
CM i—
1 O CM
CO O UO- — •
r— r—
i cn
CM
^~
*—*.
r—
CM
r^ CD ^*»
1 LO **^^
CM CT> r—
| ^~
CM
VO
^— ^
CM
Is* O CM
1 LO — '
r- r—
1 Ol
CM
p—
x— ^
S-
.c
^^
CO
c
0
-M
^_x
« i-
c o -^
•r— -i— CO
E -P C
0 0
" 3 -P
T3 CO
C •(-> co « E
3 f—
r— **-"*
*^^
OJ
en •
• r***
tf)
CO
10
^—X.
O
00 *-^
"CM
CO i—
CM **— ^
v»^
p.—
If) •
• r—
^f" CO
VO
VO
E
O
co
*^_*
«^-^
C U-
•r- O
E ^~^
^«
BO
o
•P *O "
C -U
*(—
co
CO r— IT)
o 10 CM
o • .
o o
**^s
CT> oo
«3- i^. CM
^- CM I —
r-! o o
*^— » ^-^>
.— -VO'-sO
«*• co •— o
o o CM co
o o r- •
. . . o
o^o^o-^
o
r— «*• CM 10
IO CM CO i —
• • • •
en oo o o
^~*r~~*t~~*
— -r~- 10 LO
CO CM CO VO
o o 10 CM
00 • •
. . o o
o o« >
v—*^— ^
OO CM
LO OO 00 CO
LO i — CM r—
^^ iO CD CD
*-~*^^^~*
'—•i— CT> ^1-
CM CM 00 O
O O **• CM
00 • •
• -00
*~-s*~^
CM CM
cr> i — CM o
«* 00 CM r —
LO *3- O O
4->
Uf
-C 3
o -o<-«
•• 4J O -l->
CO *O i- CJ
CO Q. 3
O ^ — * "O
•r- S- M- «f- O
CO O) O O i-
CO 4-> CO • — » Q.
'E •>- •5. o IT o «*-
CD C|_ j_ ro x: 4-> O
cn *^» ^».
CD "O^^- i- -Q O C
-l-> C D)i — -r- O
g^— ^^^-* &« 4->
•P ^^
3 O) COCO S- O) -Q
O -Q "O E -C £ r—
•^ O ^W ^^. ^x. v*^^--x
4-> i- O> C7> Cn O>
s- o- e E -x ^
O-
VII-14
-------
The charging and refining phases of the smelting process
were tested. Four runs were conducted during the testing period.
Table VI1-7 summarizes the test results.
VII-15
-------
to
S-
OJ
CO
IV, «3" LO CM
• • * •
CO i— O CD
*a-
o o
O> O T-
> c c
O (U
CQ re
o i
c -c to
to o -(->
to
re
CQ
CO
o
(/>
Ol
CO O CO CT>
CM v-.O CO IT)
CM l*~ i
I O O "sl-
r—i— CM *!•*—
I r— i—
r— r— IO
r— O
** r~*
o^—
co
co i—
in *a-
oo
o oo
in i —
CM
— -oo
en r^
If) LO CM «*
o o . •
o o •— o
CD O '
v -I»^ LO
<& o
«* *!• LO CM
• • • •
t— i— O O
c o
C 3
. CO
a:
(4-
o
to
•o
O)
IO (/>
(U C
JC O
C C OJ
•i- -^ CJ 10
EE-§§
« " O 4->
0)0)5-
e e Q. o
•r- »r— «i—
4-> -4-> CO S_
•P -»J
•*-> +-> O O>
to ro O) £=
0) (U C
O
O)
O)
S-
3
S-
O)
Q.
co to
c o
o «—»
••- s- LI-
CO a) u
CO •»-> tO
,
O
i- ja o c
CDi -- r- O
*— — - S- 4J
3 0) LOCO
O J3 T) E
S- O) JQ
o: Q h- o: H-I
O
(O
•U
LL- I—
+J J-
S- Q.
re
Q.
>O> C7> O)
E -^ -^
VH-lb
-------
Appendix IX
Representative Model Copper Facilities Using
Gas Blending
-------
-------
INTRODUCTION
This appendix presents data summaries of the opacity tests
performed by EPA to develop the visible emissions standards for
primary copper, lead, and zinc smelters. The data were gathered
from a dual-stage acid plant and from a lead blast furnace baghouse
at the ASARCO copper and lead smelter in El Paso, Texas.
Visible emission readings were taken every 15 seconds using
Method 9 contained in Title 40 of the Code of Federal Regulations,
Part 60 (40 CFR 60), Appendix A, first published in the December
23, 1971, Federal Register. The observers viewed the stacks from
vantage points approximately perpendicular to the plume and avoided
facing direct sunlight. They studied the point of greatest opacity
in the plume and recorded data to the nearest 5% opacity. All
observers were qualified according to the procedure described in
Method 9.
VIII-1
-------
DUAL-STAGE ACID PLANT OPACITY DATA
Visible emissions data were gathered from a double-absorption
sulfuric acid plant to develop the standard limiting visible
emissions discharged from smelters which utilize a sulfuric acid
plant to control sulfur dioxide emissions. This section contains
the data obtained at the American Smelting and Refining Company
copper smelter in El Paso, Texas.
The dual-stage acid plant under consideration has been operating
since December 1972 and controls the emissions from the smelter's
copper converter operations. There are three Pierce-Smith converters,
which are operated such that one or two converters are on-line at the
same time, but never three.
Two qualified observers viewed the opacity of the emissions
from the acid plant stack for approximately 10 hours, covering a
period of two days. The stack was observed for approximately 4 hours
the first day and 6 hours the second day, with breaks for the observers
being staggered so that at least one observer was taking data at all
times except for a one-hour simultaneous lunch break the second day.
The sky was clear with "little or no wind, which provided good
conditions for observing opacity during both days.
The observers have been designated as readers R-l and R-2.
R-l observed the acid plant stack over the two-day period for a total
of 591 minutes. Except for a fivei-minute period when opacities
reached as high as 30%, R-l observed all opacities as zero percent.
VIII-2
-------
R-2 observed the stack for a total of 658 minutes over the two-day
period. Except for a six-minute period when opacities reached as
high as 35% and corresponded with the five-minute period of high
readings for R-l, R-2 observed all opacities as zero percent (see
Table VIII-1).
VIII-3
-------
Table VIII-1
Opacity Readings at ASARCO Sulfuric Acid Plant - El Paso, Texas
%
Date Observer Opacity
Oct. 29 & 30, R-l 30
1973
15
10
0
Oct. 29 & 30, R-2 35
1973
30
25
20
15
10
5
0
Number
of
Occurrences
7
3
8
2346
1
4
5
9
3
1
1
2608
Total Time
of
Opacity
(mi n . )
1.75
0.75
2.00
586.50
0.25
1.00
1.25
2.25
0.75
0.25
0.25
652
% of
Total
Readings*
0.30
0.13
0.34
99.23
0.04
0.15
0.19
0.34
0.11
0.04
0.04
99.09
Cumulative
A>
0.30
0.43
0.77
100.00
0.04
0.19
0.38
0.72
0.83
0.87
0.91
100.00
*Total Readings - R-l = 591 nrin. x 4 = 2364 readings
R-2 = 658 min. x 4 = 2632 readings
VIII-4
-------
LEAD BLAST FURNACE BAGHOUSE OPACITY DATA
Visible emissions data were gathered from the American Smelting
and Refining Company's lead blast furnace baghouse in El Paso, Texas,
to develop the standard limiting visible emissions discharged from
fabric filters at primary lead and zinc smelters.
ASARCO has three blast furnaces at this plant, each with the
capacity of producing 150 tons of lead per day. Two of the furnaces
were on-line and operating at full capacity during all observations
used in this appendix. The furnaces discharge through a spray
chamber and the baghouse, then out six 108-ft stacks. Each of the
stacks serves 2 of the 12 sections in the baghouse. A dross furnace
also discharges through the spray chamber and into the baghouse.
The combined flow rate from the blast furnaces and the dross furnace
is approximately 160,000 scfm.
The baghouse is made of concrete and has 12 sections with 80
bags per section (total of 960 bags). Each bag is wool, is 30 feet long,
and has a diameter of 18 inches. The cleaning cycle is activated
when a pre-selected pressure is reached at the inlet to the baghouse.
A damper closes at the inlet to the section to be cleaned, and the
bags are then shaken. After a 5- to 40-second delay for dust
settling after shaking has stopped, the section is reopened.
If the pressure has not dropped sufficiently, the cycle is carried out
on the next section. It is normal for two or three sections to be
cleaned in succession before the pressure drops sufficiently. When
the pressure increases to the pre-selected level, the first section
VIII-5
-------
to be cleaned is the next section 1n succession after the last section
cleaned In the previous cycle.
For 4-1/2 hours on November 1, 1973, two qualified observers,
R-l and R-2, determined the opacity of the gases discharged from the
baghouse. The final 2-1/2 hours were not used in this appendix because
the blast furnace was not operating at full capacity. February 5 and 6,
1974, two more qualified observers, R-3 and R-4, viewed the emissions
from the baghouse for seven hours each day. The weather conditions
were clear to partly cloudy with little or no wind during both
observation periods.
The first two observers, R-l and R-2, noted the majority of the
opacity readings during the two-hour observation period to be zero
percent. However, there were recurrent periods of visible emissions
in which the opacity reached as high as 40%. During the first hour
the opacity was greater than 20% for an average of 3.87 minutes, while
during the second hour opacity was greater than 20% for an average of
1.87 minutes. During the entire observation period, between 87 and
92% of the readings were 20% or below (see Table VI11-2).
The second two observers, R-3 and R-4, recorded the majority
of the opacity readings during their 14-hour observation peridd
to be zero percent. However, as was the case of the first two
observers, they encountered periodic recurrences of visible emissions,
reaching as high as 35%. The opacities were greater than 20% for an
average of 5 seconds per hour with a maximum of 30 seconds per hour.
During this observation period, 99.99% of the readings were below 20%
(see Table VIII-3).
VI11-6
-------
Table VIII-2
Opacity Readings at ASARCO Lead Blast Furnace - El Paso, Texas
%
Date Observer Opacity
Nov. 1, 1973 R-l 40
35
30
25
20
15
10
5
0
Nov. 1, 1973 R-2 40
35
30
25
20
15
10
5
0
Number
of
Occurrences
2
6
4
19
29
19
10
0
391
2
1
10
1
24
1
31
0
410
Total Time
of
Opacity
(min.)
0.50
1.50
1.00
4.75
7.25
4.75
2.50
0.00
97.75
0.50
0.25
2.50
0.25
6.00
0.25
7.75
0.00
102.50
% of
Total
Readings*
0.42
1.25
0.83
3.96
6.04
3.96
2.08
0.00
81.46
0.42
0.21
2.08
9.21
5.00
0.21
6.46
0.00
85.42
Cumulative
%
0.42
1.67
2.50
6.46
12.50
16.46
18.54
18.54
100.00
0.42
0.63
2.71
2.92
7.92
8.13
14.59
14.59
100.01
*Total Readings for 2 hours = 2 x 60 x 4 = 480.
VIII-7
-------
Table VIII-3
Opacity Readings at ASARCO Lead Blast Furnace, El Paso, Texas
%
Date Observer Opacity
Feb. 5 & 6, R^3 35
1974
30
20
15
10
5
0
Feb. 5 & 6, R-4 15
1974
10
5
0
Number
of
Occurrences
^1
2
9
17
37
74
3220
5
17
148
3190
Total Time
of
Opacity
(min.)
0.25
0.50
2.25
4.25
9.25
18.50
805
1.25
4.25
37.00
797.50
% of
Total
Readings*
0.03
0.06
0.27
0.51
1.1
2.2
95.83
0.15
0.51
4.4
94.94
Cumulative
%
0.03
0.09
0.36
0.87
1.97
4.17
100.00
O.T5
0.66
5.06
100.00
*Total readings for 14 hours = 4 x 14 x 60 = 3360 readings or 840 minutes
(1 reading = 15 seconds)
VIII-8
-------
The periods of higher opacity occurred at approximately the same
time as the bag-shaking step of the cleaning cycle. Higher emissions
can occur when the damper to the section most recently cleaned reopens,
allowing a portion of the dust shaken from the bags to exit out the
stack.
VIII-9
-------
Appendix VIII
Visible Emission Observations
-------
Figure IX-1. Gas Blending Model for Calcine Charge
Smelting Facility
Concentrate
I
Fluid-Bed
Roaster
I
Reverberatory
Furnace
Converters
Air
©
24
Copper
(2J
24
fr/day 24 24 294812948 1
SCFM 45,600 17,100 36,800 18,400 14,300 37,700 - 99,500 81,100 82,000 100,400 62,700
% S02 2.25 1077 10.5 8.75 - 5.30 4.96 5.80 6.00 4.35
0,
10.5 10.5
10.5 10.5 - 7.00 6.25 6.29 7.07
5.00
hr/day 2
SCFM
% S02
%02
9
714
0
21
— — -131 —
4
4833
0
21
8
3652
0
21
1
1952
0
21
hr/day 29481
SCFM 99,500 81,814 86,833 104,052 64,652
S02
02
5.30
7.00
4.90
6.37
5.50
7.11
5.79
7.53
4.2
5.48
IX-1
-------
Figure IX-2. Gas Blending Model for a Green-Charge
Smelting Facility
Concentrate
I
Reverberatory
Furnace
Converters
T
Copper
hr/day
SCFM
% so2
% 0,
\L/
24
82,600
1.75
5
5
61 ,600
7
10.5
11
30,800
7
10.5
W
2 5 1
36,900 65,500
9 8.5
11.75 11
hr/day 5 11 2 51
SCFM 144,200 113,400 119,500 148,100 82,600
% S02 3.99 3.18 3.99 4.-74 1.75
% 02 7.3 6.49 6.23 7.65 5
IX-2
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
1. REPORT NO.
EPA-450/2-74-002-a
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Background Information for New Source Performance
Standards: Primary Copper, Zinc, and Lead Smelters.
Volume 1 --Proposed Standards
5. REPORT DATE
October 1974
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Protection Agency
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AMD PEHIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This document presents information on the derivation of proposed standards "of
performance for new and modified primary copper, zinc, and lead smelters. The
report describes the various extraction processes available for copper, zinc, and
lead, the various systems available for controlling emissions of sulfur oxides
and particulate matter from these processes, the economic impact of the proposed
standards, the environmental and energy-consumption effects associated with the
various processes and control systems, and the general rationale for the proposed
standards.
The standards developed require control at levels typical of best demonstrated
existing technology. These levels were determined by extensive on-site investiga-
tions; consideration of process design factors, maintenance practices, available
test data, and characteristics of plant emissions; comprehensive literature
examination; and consultations with the National Air Pollution Control Techniques
Advisory Committee, members of the academic community, and industry.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Copper
Zinc
Lead
Sulfur dioxide
Smelting
Sulfuric Acid plants
New source -performance standards
18. OISTRIBUTION^TATEMENT
Release Unlimited
b.IDENTIFIERS/OPEN ENDED TERMS
19. SECURITY CLASS (This Report)
20. SECURITY CLASS {Thispage)
c. COS AT I Field/Group
21 NO. OF PAGES
22 PRICE
EPA Form 2220-1 (9-73)
X-l
U.S. GOVERNMENT r'rtlMTIfIG OFFICE: 1974 - 640-878/637 - Region 4
-------
-------