REPORT
ESTIMATING AND CONROLLING FUGITIVE LEAD EMISSIONS
FROM INDUSTRIAL SOURCES
Final Report
EPA Contract No. 68-02-4395
Work Assignment 41
MRI Project 8987-41
September 28, 1990
MIDWEST RESEARCH INSTITUTE 425 Volker Boulevard, Kansas City, MO 64110-2299 • (816) 753-7600
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REPORT
ESTIMATING AND CONROLLING FUGITIVE LEAD EMISSIONS
FROM INDUSTRIAL SOURCES
Final Report
EPA Contract No. 68-02-4395
Work Assignment 41
MRI Project 8987-41
September 28, 1990
MIDWEST RESEARCH INSTITUTE 425 Volker Boulevard, Kansas City, MO 64110-2299 • (816) 753-7600
-------
ESTIMATING AND CONROLLING FUGITIVE LEAD EMISSIONS
FROM INDUSTRIAL SOURCES
Final Report
EPA Contract No. 68-02-4395
Work Assignment 41
MRI Project 8987-41
Prepared for:
Denise Scott, Work Assignment Manager
Air Quality Management Division
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, N.C. 27711
Prepared by:
Rick Marinshaw and Dennis Wallace
Midwest Research Institute
401 Harrison Oaks Boulevard
Cary, North Carolina 27513
September 28, 1990
MIDWEST RESEARCH INSTITUTE 425 Volker Boulevard, Kansas City, MO 64110-2299 • (816)753-7600
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TABLE OF CONTENTS
Page
LIST OF FIGURES iv
LIST OF TABLES v
SECTION 1.0 INTRODUCTION 1
SECTION 2.0 FUGITIVE EMISSION SOURCES 3
2.1 OPEN DUST FUGITIVE EMISSIONS 3
2.1.1 Industrial Paved Roads 3
2.1.2 Unpaved Roads 7
2.1.3 Storage Piles 8
2.2 PROCESS FUGITIVE EMISSIONS 13
2.2.1 Solid Materials Handling Operations 14
2.2.2 Materials Processing Operations 15
2.2.3 Furnaces 15
2.2.4 Hot Metal Transfer and Processing 19
2.2.5 Metal Casting 20
SECTION 3.0 INDUSTRIAL SOURCES OF FUGITIVE LEAD EMISSIONS 21
3.1 PRIMARY LEAD SMELTING 21
3.1.1 Process Description 21
3.1.2 Primary Lead Smelting Fugitive Emissions
Sources 25
3.1.3 Characteristics of Fugitive Dust Sources... 30
3.2 SECONDARY LEAD SMELTING
3.2.1 Process Description 30
3.2.2 Secondary Lead Smelting Fugitive Emission
Sources 43
3.2.3 Characteristics of Fugitive Dust Sources... 45
3.3 LEAD-ACID BATTERY MANUFACTURING
3.3.1 Process Description 46
3.3.2 Fugitive Emissions Sources 51
3.4 GRAY IRON FOUNDRIES 53
3.4.1 Process Description 53
3.4.2 Fugitive Emission Sources 57
3.4.3 Fugitive Emission Rates 61
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TABLE OF CONTENTS (continued)
SECTION 4.0 PROCEDURES FOR ESTIMATING FUGITIVE EMISSIONS
Page
4.1 PRIMARY LEAD SMELTING 63
4.1.1 Open Dust Fugitive Emissions Estimation.... 63
4.1.2 Process Fugitive Emissions Estimation 64
4.2 SECONDARY LEAD SMELTING 64
4.2.1 Open Dust Fugitive Emissions Estimation 64
4.2.2 Process Fugitive Emissions Estimation 69
SECTION 5.0 CONTROL OF FUGITIVE EMISSIONS
5.1 OPEN DUST FUGITIVE EMISSIONS CONTROLS 71
5.1.1 Paved Road Control Measures 71
5.1.2 Unpaved Road Control Measures 73
5.1.3 Storage Pile Control Measures 79
5.2 PROCESS FUGITIVE EMISSIONS CONTROLS
5.2.1 Local Ventilation Systems 82
5.2.2 Building Enclosure/Evacuation 90
5.2.3 Other Process Fugitive Controls 90
5.3 INDUSTRY-SPECIFIC CONTROLS ; 92
5.3.1 Primary Lead Smelter Fugitive Emission
Control s 92
5.3.2 Secondary Lead Smelter Fugitive Emission
Control s 95
SECTION 6.0 REFERENCES
APPENDIX A. PROCEDURES FOR SAMPLING SURFACE/BULK MATERIALS A-l
APPENDIX B. PROCEDURES FOR LABORATORY ANALYSIS OF SURFACE/BULK
SAMPLES B-l
APPENDIX C. PROCEDURES FOR ESTIMATING LEAD EMISSIONS FROM OPEN
FUGITIVE DUST SOURCES C-l
APPENDIX D. EXAMPLE FUGITIVE EMISSION INVENTORY CALCULATIONS
HYPOTHETICAL .SECONDARY LEAD SMELTER D-l
n i
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LIST OF FIGURES
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Mean annual number of days with at least 0.01 in. of
precipitation
Typical blast furnace system for secondary lead
production
Typical reverberatory furnace system for secondary lead
production
Typical primary lead processing scheme
Updraft sintering with weak gas recirculation ,
Typical secondary lead smelting and refining scheme.
Process flow diagram for storage battery production.
Composite flow diagram for the gray iron foundry
industry
Mold and core making
Chemical dust suppressant control efficiency model
Overview of modified local exhaust ventilation system..
Blast furnace slag tapping hood
Skip hoist ground level loading station ,
Alternate suggested design concept for blast furnace
launder and block casting hoods
Page
10
16
17
22
23
35
49
55
56
78
84
85
86
87
Suggested design concept for blast furnace lead
tapping hood system (lead tap, launder, and block
casting)
Rotary furnace charging and tapping controls
Finished metal ladle cooling hood
Suggested design concept for refining kettle hoods.
Suggested design concept for dross pot hoods
Flash agglomeration furnace
89
91
98
99
100
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LIST OF TABLES
TABLE 1.
TABLE 2.
TABLE 3.
TABLE 4.
TABLE 5.
TABLE 6.
TABLE 7.
TABLE 8.
TABLE 9.
TABLE 10.
TABLE 11.
TABLE 12.
TABLE 13.
TABLE 14.
TABLE 15.
TABLE 16.
TABLE 17.
TABLE 18.
INDUSTRIAL PAVED ROAD SILT LOADINGS.
TYPICAL VALUES FOR PAVED ROAD INDUSTRIAL AUGMENTATION
FACTOR (I)
TYPICAL SILT CONTENT VALUES OF SURFACE MATERIAL ON
INDUSTRIAL AND RURAL UNPAVED ROADS
FUGITIVE LEAD EMISSION SOURCES FOR A PRIMARY LEAD
SMELTER
ESTIMATED OPEN FUGITIVE DUST EMISSIONS AT TWO PRIMARY
LEAD SMELTERS ,
TRAFFIC AND ROAD DUST DATA FROM TWO PRIMARY LEAD
SMELTERS
LEAD CONTENT OF FUGITIVE EMISSIONS AT THREE PRIMARY LEAD
SMELTERS
SECONDARY LEAD SMELTING OPERATIONS IN THE U.S.
FEED MATERIALS AND FURNACE PRODUCTS, REPORTED BY ONE
PLANT WITH A BLAST/REVERBERATORY COMBINATION
FUGITIVE EMISSION SOURCES IN SECONDARY LEAD SMELTERS.
LEAD CONTENT OF SECONDARY LEAD SMELTER MATERIALS
RESULTS OF ROADWAY DUST LOADING SAMPLING AT A SECONDARY
LEAD SMELTER
LEAD-ACID BATTERY MANUFACTURING-TYPICAL CONTROL
DEVICES
FUGITIVE EMISSION SOURCES IN IRON FOUNDRIES...
FUGITIVE EMISSIONS FACTORS FOR IRON FOUNDRIES.
MOISTURE, SILT, AND LEAD CONTENT OF STORAGE PILE
MATERIALS AT TWO PRIMARY LEAD SMELTERS
PROCESS FUGITIVE EMISSION FACTORS FOR PRIMARY LEAD
SMELTING
EMISSION FACTORS FOR PROCESS FUGITIVE EMISSION SOURCES
IN SECONDARY LEAD SMELTERS
Page
5
6
9
26
27
31
32
34
42
44
47
48
52
58
62
65
66
70
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LIST OF TABLES (continued)
Page
TABLE 19. NONINDUSTRIAL PAVED ROAD DUST SOURCES AND PREVENTIVE
CONTROLS 72
TABLE 20. MEASURED EFFICIENCY VALUES FOR PAVED ROAD CONTROLS 74
TABLE 21. CONTROL TECHNIQUES FOR UNPAVED TRAVEL SURFACES 75
TABLE 22. CONTROL TECHNIQUES FOR STORAGE PILES 80
TABLE 23. SPECIFIC PROCESS FUGITIVE LEAD EMISSION SOURCES AND
POTENTIAL CONTROLS AT PRIMARY LEAD SMELTERS 94
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ESTIMATING AND CONTROLLING FUGITIVE LEAD EMISSIONS FROM
INDUSTRIAL SOURCES
1.0 INTRODUCTION
The 1977 amendments to the Clean Air Act added lead to the list of
six criteria pollutants and established the primary and secondary national
ambient air quality standards (NAAQS) for lead as 1.5 micrograms per cubic
meter (wg/m ) averaged over a calendar quarter. These standards must be
achieved at the industry fenceline and/or property line. Since then,
average ambient concentrations of lead have decreased dramatically. For
example, during the period 1980 to 1986, the maximum quarterly averages
for ambient lead for all monitoring stations dropped from 0.91 ug/m to
0.26 ug/m , and annual averages for ambient lead concentrations fell from
0.64 yg/m3 to 0.17 yg/m3.1 Much of this reduction was due to the decrease
in the use of leaded gasolines, but gasoline emissions are expected to
stabilize soon. To achieve further reductions in lead emissions, other
sources must be targeted.
Although total nationwide lead emissions have been reduced,
exceedances of the lead NAAQS often occur. In 1989, 18 of 530 lead
monitors included in the Aerometric Information Retrieval System (AIRS)
data base recorded at least one exceedance of the 1.5 yg/m3 standard.
However, this fraction of exceedances is likely an underestimation of the
magnitude of the problem. Many of the major lead-emitting industries do
not have fenceline monitors to record NAAQS exceedances. For example, of
the 26 operating primary and secondary lead smelters, only 12 have
fenceline monitors for which data are recorded in the AIRS data base. Of
these 12 lead smelters, 11 reported at least one exceedance during the
period 1987 to 1989.
In order to attain the lead NAAQS at the fencelines of a number of
facilities, further reductions in lead emission must be achieved. Point
sources at the industries of concern are largely controlled. Thus, for
many facilities, further emission reductions may be possible only through
the control of fugitive emissions. Furthermore, because fugitive
emissions are typically emitted closer to ground level than stack
emissions, fugitives can have a much greater impact on ambient
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concentrations at the fenceline. In many cases, the magnitude of fugitive
emissions is unknown, however. The purpose of this document is twofold--
first, to present prpcedures for estimating the magnitude of fugitive lead
emissions; and second, to present measures for effectively controlling
these fugitive emissions. This document focuses on several industries
that use or process large quantities of lead and therefore are more likely
to have significant fugitive lead emissions. As a part of an analysis of
control techniques for lead air emissions from stationary sources,
preliminary estimates of total nationwide emissions of lead were developed
for a number of source categories. The three categories having the most
significant emissions were secondary lead smelters (813 Mg/yr), gray iron
foundries (466 Mg/yr), and primary lead smelters (345 Mg/yr). Other
source categories with relatively high emission levels were ore mining
(159 Mg/yr) and lead-acid storage battery manufacture (145 Mg/yr).2 These
quantities represent total lead emissions rather than fugitive
emissions. However, the magnitude of the numbers suggests that the level
of fugitive emissions from these source categories should be examined more
closely. This report focuses on the primary and secondary lead smelting
industries. However, the fugitive emission problem for lead-acid battery
production and gray iron foundry will also be discussed.
Section 2.0 includes a general discussion of fugitive emissions.
This is followed in Section 3.0 by a description of the processes and
fugitive emissions sources for the industries of concern. Section 4.0
presents procedures for estimating fugitive emissions. Section 5.0
discusses fugitive emissions control technologies. References are
provided in Section 6.0.
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2.0 FUGITIVE EMISSION SOURCES
Fugitive emission sources can be divided into two broad categories-
process fugitive emission sources and nonprocess, or open, fugitive dust
emission sources. Process fugitive emissions sources include emissions
from mechanical and metallurgical operations that alter the physical or
chemical characteristics of the feed materials. Open fugitive dust
emission sources relate to the transfer, storage, and handling of
materials and include those sources from which particles are entrained by
the forces of wind or machinery acting on exposed materials.
The following sections present general discussions of the various
types of fugitive emission sources. First, open dust fugitive sources are
described, followed by a discussion of typical process fugitive emission
sources.
2.1 OPEN DUST FUGITIVE EMISSIONS
Open dust fugitive sources include paved and unpaved traffic areas
and storage piles. Particulate emissions occur from these sources when
previously deposited material is reentrained by vehicle traffic, by the
loading and unloading equipment, or by the action of the wind. For most
industrial plants, paved and unpaved roads are the primary sources of open
dust fugitive emissions. Fugitive dust emissions from storage pile
materials handling operations are usually insignificant in comparison to
road sources, unless the moisture content of the storage pile materials is
extremely low. Emissions due to wind erosion of storage piles are
likewise insignificant unless wind speeds are unusually high.
This section begins with a discussion of fugitive dust emissions from
paved roads. Next, unpaved road fugitive dust emissions are discussed.
Finally, fugitive emissions that results from materials handling and wind
erosion of storage piles are described. Most of the material presented in
this section is adopted from Reference 3.
2.1.1 Industrial Paved Roads
Open dust fugitive emissions from paved roads depend upon the loose
surface material and traffic characteristics of the road. These emissions
have been determined to vary directly in proportion to the surface
material loading and silt content of the road. The surface material
loading is the amount of loose dust on the road surface and is measured in
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units of mass of material per unit area. (Surface material loading for a
specific road is typically expressed in units of mass per unit length of
road, however.) The silt content is the percentage of silt (i.e.,
particles less than or equal to 75 microns in diameter) in the loose
surface dust. Some typical values for silt loadings on industrial paved
roads are presented in Table 1. Other factors that affect industrial
paved road fugitive emissions include the volume of traffic, number of
traffic lanes, average vehicle weight, and the degree to which vehicles
travel in nearby unpaved areas (thereby allowing more dust to be deposited
on the paved road). This last factor is known as the industrial
augmentation factor and ranges in value from 1.0 to 7.0. Higher values
indicate greater fugitive dust emissions. Typical values for this factor
are found in Table 2.
The magnitude of fugitive lead emissions (or emissions of any other
substance) may be estimated by direct proportion with the percent by
weight of lead (or substance of concern) in the silt fraction. Because of
variations from location to location, site-specific data should be used
for all of the above-mentioned factors whenever possible.
The fugitive lead emission factor for industrial paved roads in units
of kilograms per vehicle kilometer traveled (kg/VKT) or pounds per vehicle
mile traveled (Ib/VMT) can be determined by the following modified
equation for total suspended particulate emissions:
0 7
E = 0.022 I (TO%)(£HT|X 230^277-) ' (kg/VKT) (1)
E = 0.022 I ( C )(lj(S jrLwWj ' (1b/VMT)
where:
E = emission factor, kg/VKT (Ib/VMT);
C = average percent by weight of lead (or other substance) in the
silt fraction;
I = industrial augmentation factor (dimensionless);
n = number of traffic lanes;
s = average surface material silt content, percent;
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TABLE 1. INDUSTRIAL PAVED ROAD SILT LOADINGS3
Industry
Copper smelting
Iron and steel
production
Asphalt batching
Concrete batching
Sand and gravel
processing
No. of
sites5
1
6
1
1
1
No. of
samples
3
20
3
3
3
S1ltf percent
Range
15.4-21.7
1.1-35.7
2.6-4.6
5.2-6.0
6.4-7.9
w/w
Mean
19.0
12.5
3.3
5.5
7.1
No. of
travel
lanes
2
2
1
2
1
S1lt loading^
Range
188-400
0.09-79
76-193
11-12
53-95
g/m2
Mean
292
12
120
12
70
^Reference 4.
The data presented in this table are based on an EPA-sponsored sampling and analysis program, for which
the number of samples specified in the table were collected at the specified number of sites.
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TABLE 2. TYPICAL VALUES FOR PAVED ROAD
INDUSTRIAL AUGMENTATION FACTOR (I)a
I Conditions
1.0 Travel on paved roads only
3.5 Travel on paved roads with unpaved shoulders~20 percent of
vehicles travel with one set of wheels on shoulder
7.0 Traffic enters from unpaved roads
Reference 5. Factors are dimensionless.
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L = average surface dust loading, kg/km (Ib/mile); and
W = average vehicle weight, Mg (ton).6
2.1.2 Unpaved Roads
As is the case for paved roads, particulate emissions occur whenever
a vehicle travels over an unpaved surface. Unlike paved roads, however,
the road surface itself is the source, of the emissions rather than any
"surface loading." Unpaved roads and travel surfaces have historically
accounted for the greatest share of particulate emissions at a number of
industries. For example, unpaved sources were estimated to account for
roughly 70 percent of open dust sources in the iron and steel industry
during the 1970's. In addition to roadways, many industries often contain
other unpaved travel areas. These areas may often account for a
substantial fraction of traffic-generated emissions from individual
plants.
Fugitive dust emissions from unpaved roads, like paved road fugitive
emissions, are directly proportional to the silt content of the surface
material. In addition, fugitive lead emissions can be estimated by direct
proportion with the lead content in the silt fraction. Unpaved road
fugitive dust emissions are also proportional to the mean vehicle speed,
mean vehicle weight, and mean number of wheels. Fugitive emissions from
unpaved roads are also affected by the rainfall frequency. For particles
under 30 microns in diameter, a particle size multiplier must also be
included in the computation of emissions. However, for total suspended
particulate emissions, which is the concern here, the value of this factor
is assumed to be unity and it may be dropped from the equation.
The fugitive lead emission factor for unpaved roads per unit of
vehicle distance traveled can be estimated by the following modified
equation for total suspended particulates:
07 OS
r / «\ / ^\ / u \ /w\
E = (1.7) (_) (_) (_) (_) (*) V-""-K/ /UQ/vim (2)
u ' ^nn) 12 48 2.7 4 365 ^Kg/VM > W
07 05
E = (5.9) (JL) (*-) (L) ff) (*) <365-P)
^ } V100' 12 30 3 4 365
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where:
E = emission factor, kg/VKT (Ib/VMT);
C = percent by weight of lead in the silt fraction;
s = average silt content of road surface material, percent;
S = averge vehicle speed, km/h (mil/h);
W = average vehicle weight, Mg (ton);
w = average number of wheels (dimensionless); and
p = number of days with >0.254 iron (0.01 in.) of precipitation per
year.
Measured silt values for a number of industries are given in Table 3. As
is the case for paved road fugitive dust emission factors, the use of
site-specific data is strongly encouraged.
The number of wet days per year, p, for the geographical area of
interest should be determined from local climatic data. Figure 1 gives
the geographical distribution of the mean annual number of wet days per
year in the United States.
2.1.3 Storage Piles
In most industrial settings, materials are stored uncovered in
outside locations. Although this practice facilitates transfer of
materials into and out of storage, it also subjects the storage to several
forces that can introduce dusts into the air. In general, there are three
mechanisms by which storage piles can act as sources of fugitive dust
emissions:
1. Equipment traffic in the storage area;
2. Materials handling operations; and
3. Wind erosion of pile surfaces and surrounding areas.
Each of these mechanisms is discussed in more detail below.
As mentioned above, open dust fugitive emissions from storage piles
are generally insignificant in comparison to fugitive emissions from paved
and unpaved traffic areas. However, under worst case conditions storage
pile emissions can be significant and therefore should be taken into
consideration when compiling an emissions inventory. On the other hand,
fugitive emissions from partially or fully enclosed storage piles will
generally be much less than the emissions that would originate from the
same storage pile without the protection of the enclosure.
8
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TABLE 3. TYPICAL SILT CONTENT VALUES OF SURFACE MATERIAL ON INDUSTRIAL
AND RURAL UNPAVED ROADSa
Industry
Copper smelting
Iron and steel production
Sand and gravel processing
Stone quarrying and processing
Taconite mining and processing
Western surface coal mining
Rural roads
Road use or
surface material
Plant road
Plant road
Plant road
Plant road
Haul road
Service road
Access road
Haul road
Scraper road
Haul road
(freshly graded)
Gravel
Dirt
Crushed limestone
Plant
sitesD
1
9
1
1
1
1
2
3
3
2
1
2
2
Test
samples
3
20
3
5
12
8
2
21
10
5
1
5
8
Silt,
percent by
Range
15.9-19.1
4.0-16.0
4.1-6.0
10.5-15.6
3.7-9.7
2.4-7.1
4.9-5.3
2.8-18
7.2-25
18-29
NA
5.8-68
7.7-13
weight
Mean
17.0
8.0
4.8
14.1
5.8
4.3
5.1
8.4
17
24
5.0
28.5
9.6
Note: NA = Not applicable
^Reference 7.
The data presented in this table are based on an EPA-sponsored sampling and analysis program, for which
the number of samples specified in the table were collected at the specified number of sites.
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•••
III
110
A 40 100 JOO )00 100 100
~~~ Mil 11
Figure 1. Mean annual number of days with at least 0.01 in. of precipitation.'
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2.1.3.1 Equipment Traffic in Storage Areas. Fugitive emissions from
equipment traffic between, in the vicinity of, or on storage piles should
be handled as vehicle traffic emissions. For estimation purposes, the
equation for unpaved roads (Equation 2) should be used. However, a
distinction should be made between traffic on and traffic between or in
the vicinity of storage piles. The silt content used 1n Equation 2 for
traffic on the pile should be the silt content of the pile; the silt
content used for traffic between or in the area of storage piles should be
that of the silt content between (or in the area of) the piles.
2.1.3.2 Materials Handling. Fugitive dust emissions result whenever
material is added to or removed from a storage pile. Although some
limited studies on specific industries have demonstrated a relationship
between silt content and materials handling emissions, an analysis of
existing test data has shown that fugitive emissions from storage pile
transfer operations can be estimated using only the mean wind speed and
material moisture content. (It thus follows that worst case emissions
arise from dry windy conditions.) However, in order to estimate fugitive
lead emissions from materials handling, it is necessary to determine the
percent of lead by weight in the silt fraction of the material.
Transfer operations involving storage piles can be classified as
continuous or batch. An example of a continuous operation is adding
material to a pile by conveyor; an example of a batch transfer operation
is a truck dumping a load of material onto a pile. Regardless of the type
of transfer operations, the following modified equation for total
suspended particulate emissions can be used to estimate fugitive lead
emissions:
E = 0.0016 () ±_. (kg/Mg)
E = 0.0032 (} - rir (Ib/ton)
11
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where:
E = emission factor, kg/Mg material handled (Ib/ton);
C = percent by weight of lead in the silt fraction;
U = mean wind speed, m/s (mph); and
M = material moisture content, percent.
Note that the general materials handling emissions equation from
which Equation 3 originates also includes a particle size multiplier
(k). However, for total suspended particulate emissions, the value of
this factor is unity and thus does not enter into Equation 3.
It should be emphasized that the above equation should be used only
for storage pile materials handling operations that take place at the
beginning or end of a process. Materials transfer between or within
processes (typically by conveyor) are generally unique to the specific
processes. For the purposes of this document, fugitive emissions from
this type of material transfer are treated as process fugitive emissions
and are discussed in Section 2.2. Additionally, it should be noted that
there are specific ranges for silt content (0.44 to 19 percent), moisture
content (0.25 to 4.8 percent), and wind speed (0.6 to 6.7 m/sec)
recommended for this equation. Outside these ranges, the reliability of
the equation decreases.
2.1.3.3 Wind Erosion. Dust emissions may be generated by wind
erosion of open aggregate storage piles and exposed areas within an
industrial facility. For the purposes of estimating these emissions,
storage piles are classified as active storage piles and inactive storage
piles. Active piles are those that are used at least every 2 days.
Inactive storage piles are those that are used less frequently. In
addition, large "active" piles are considered to be inactive piles if the
portion of the pile in use amounts to only a small percentage of the total
pile volume.
Fugitive dust emissions from active storage piles are a function of
the silt content of the material stored, wind speed, and rainfall
frequency. Fugitive lead emissions can be estimated by direct proportion
with the lead content of the silt fraction of the material. The following
equation can be used to estimate fugitive lead emissions from wind erosion
of active storage piles:
12
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E " :-9 <> <> <> (> (^-"ecure) (4)
E ' K7
where:
E = emission factor, kg/d-hectare (Ib/d-acre);
C = percent by weight of lead in the silt fraction;
s = average silt content of storage pile material, percent;
p = number of days with >0.25 mm (0.01 in.) of precipitation per
year; and
f = percentage of time that the unobstructed wind speed exceeds
5.4 m/sec (12 mph) at the mean pile height.
A more complex model has also been developed for estimating fugitive
dust emissions due to wind erosion from storage piles. However, because
the wind erosion model on which Equation 3 is based was developed using
total suspended particulate monitors, it is more appropriate for
estimating fugitive lead emissions. A discussion of the other wind
erosion model can be found in Reference 3.
2.2 PROCESS FUGITIVE EMISSIONS
Process fugitive emissions are released from industrial operations to
the atmosphere either directly from the process or through building
openings such as windows, doors, or roof monitors rather than through
well-defined stacks or vents. Sources of process fugitive emissions
include both processing operations, such as furnaces and crushing and
screening operations, as well as intermediate material handling
operations, such as hot metal transport and solids conveying.
As a class of sources, it is more difficult to generalize about
process fugitive emission sources than about open fugitive dust sources.
The process operations that lead to fugitive emissions vary substantially
for the different industries examined in this study and for different
plants within the same industry. Further, characteristics of the
emissions that affect control vary much more from source to source for
process fugitive emissions than they do for fugitive dust sources. In
13
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particular, process fugitive emissions vary widely with respect to
configuration of the release point, plume geometry and temperature, and
particle size distribution of particulate matter.
Although process fugitive emission sources vary greatly, they can be
grouped into five general categories of sources that have comparable
characteristics. These five categories are solid materials handling
operations, materials processing operations, furnaces, and hot metal
transfer and processing, and metal casting. The remainder of this section
provides brief descriptions of these five categories of sources. Each
subsection describes typical processes covered by the general category and
summarizes key characteristics of the emission streams that affect
controllability of the sources. More detailed discussion of the specific
process fugitive emission sources found within each industry are presented
in Section 3.0.
2.2.1 Solid Materials Handling Operations
Each of the industrial processes under study includes handling and
transfer of solid materials.as intermediate steps in the process.
Examples of materials handled within these industries include coke and
coal, limestone fluxing materials, sinter, slag, and air pollution control
device dust. Each of these materials contains fines that are emitted
during handling and transfer operations. These handling and transfer
operations differ from the fugitive dust sources described in Section 2.1
in that they occur after the material leaves the raw material storage area
(frequently they are intermediate materials in the process) and often are
enclosed within process buildings. However, the handling operations
themselves and the characteristics of the emissions are comparable to
those described in the fugitive dust discussion.
Within these industries, the handling of solid materials can be
accomplished either mechanically with a conveyor system or manually using
front-end loaders. In either case, most emissions are generated at points
where material undergoes some type of drop, such as a conveyor transfer
point or a front-end loader dump station. Generally, the emissions are at
ambient temperature and comprise relatively large size particulate
matter. The plume configuration and flow properties generally are
controlled by ventilation airflows in the vicinity of the transfer point.
14
-------
2.2.2 Materials Processing Operations
Many of the raw materials used in the industries under study must
undergo further processing before they can be used in the primary
manufacturing process. Typical materials processing operations include
crushers and hammermills, which are used to reduce the size of feedstock
such as coke ore, sinter, and batteries; screening operations, which are
used for both sizing (e.g., sinter in lead smelters) and cleaning (e.g.,
sand in iron foundries); and mixers, which are used to blend materials
(particularly core and mold materials in foundries). Each of these
processes modifies the material being processed by applying mechanical
energy to the material. This mechanical energy exacerbates fugitive
emissions via two mechanisms. First, these processes increase the amount
of fines in the material through fracturing and abrasion. Second, the
mechanical energy imparts high velocities directly to the fine materials
and generates high-velocity air streams within the process equipment and,
in doing so, increases the potential for emissions.
These processes all have similar emission characteristics, and in
general, each of the processes is enclosed. However, because of the high
energy involved in the processes, significant quantities of fugitive
emissions can be generated from process leaks. Fugitive particulate
matter is also emitted during charging and discharging of the processes.
Typically, these emissions are emitted at ambient temperatures (with
sinter crushing and screening being the primary exceptions). As with
materials handling operations, the particle size distribution is
relatively coarse, and the plume behavior is strongly influenced by
ventilation patterns in the vicinity of the process equipment.
2.2.3 Furnaces
High-temperature metallurgical furnaces are used for melting,
reducing, and refining metallic compounds in the industries under study.
In addition, sinter machines, which are considered to be furnaces for
purposes of this discussion, are used in the primary lead industry to
transform lead sulfide to lead oxide and to produce a feed material with
suitable physical properties for charging to the blast furnace. Figures 2
and 3 presents schematics of a typical blast and reverberatory furnace.
Obviously, these furnaces differ significantly with respect to
15
-------
SCRAP. DROSSES.
OIIPES. ReVKRBEHATORY
SLAi:. RERUN SLAG. SCRAP
IRON, COKE. I.IHESTONK
SI.AC
EMISSIONS
(I^ST run HACK
AKfKRRURHER
I tin Sour *:c«
I Cli«r|lng (fuglilvc)
7 SUg i«|>|iliig (fugitive)
) Le.,1 in|i|i|ng/r.««llng (liiglilvn)
4 H««lluiglc*l (.lack)
In
pnc
COOI.lHt; TUBKS
CQOI.IMC BLEED AIR
win »itna to
~T-r~V\AA
vy BACIKHISE
Jr
*->}
SIA
FAN
Figure 2. Typical blast furnace system for secondary lead production.
10
-------
HUSSIONS
I.F.AH SCRAP, OATTEHY
TI.ATCS. OXIDES
CIIARCE •
HAS OR
FUEL Oil.
fA/V\*v. L
\
(?) 0
/ SI AC
REVERBKRATOIU FURNACE
SErri,iHC
CIIAHAKR
A
A
A
A
COOt, INC TUBES
roni.INC Bl.ri:i) AIR —'
WIST RECYCLE
I ClmrgliiR (luKltlve)
2 Sing lapping (fnglltve)
) l.rxd (applcig/raal lug (fugitive)
4 Hclalltnglcal ((lack)
n n LI i
STA(
KAN
Figure 3. Typical reverberatory furnace system for secondary lead production.11
-------
configuration. They also differ widely in terms of size, material
processed, operating temperature, and operating cycle. As a consequence,
both emission quantities and emission release characteristics differ
widely across furnace types and even for the same furnace types across a
given industry. A general description of the types of fugitive emissions
generated by these metallurgical furnaces, with a qualitative summary of
how differences in furnace configuration are likely to affect emissions,
is presented below.
For these metallurgical furnaces, the charging and tapping operations
are essentially batch operations. Fugitive emissions are generated during
charging of raw materials and discharging (tapping) of product and slag.
Fugitive emissions are also generated via process leaks during normal
operations and from process upsets such as blast furnace slips.
Of all the common process operations in the industries under study,
metallurgical furnace charging operations are possibly the most varied.
Charging varies with respect to type of material charged, size of charge,
configuration of the charge opening, and characteristics of the material
remaining in the furnace when charging is initiated. Each of these
factors has an effect on emissions. The material charged to the furnace
can be raw material feedstock (e.g., blast furnaces in primary lead
smelters), scrap (e.g., cupolas in gray iron foundries and blast furnaces
or cupolas in secondary lead smelters), or a combination of molten metal
and scrap (e.g., electric arc furnaces in iron foundries). Emissions are
affected by cleanliness and temperature of the material. For example, if
a scrap load to an electric furnace contains high concentrations of lead,
fugitive lead emissions will increase when this load hits the molten bath
in the furnace. Also, fugitive emissions generally are high when molten
metal is charged.
Most furnaces have one. of three types of charging configurations.
Systems like the copper converter or the electric arc furnace are movable
or have a movable hood. In those systems, a large component of the
furnace is open during charging, and emissions are relatively high.
Furnaces like the reverberatory furnace and the cupola have vertical
openings in the upper part of the furnace through which solids are charged
mechanically or manually. These type systems generally have lower
18
-------
emissions than those described above, but the emissions still are likely
to be substantial. Finally, some blast furnaces have a two-door system to
reduce emission potential.
Regardless of the type of material charged or the configuration of
the charging system, emissions from furnace charging have two common
characteristics. First, emissions are released in a high-temperature,
buoyant plume, which complicates capture and emissions reduction. Second,
the emissions tend to be fine particles, which increases the difficulty of
control.
Most metallurgical furnaces generate two products—the metal of
interest and a slag. Both of these products must be removed by tapping.
Tapping is accomplished via one of two mechanisms. In stationary-type
furnaces such as reverberatory furnaces, cupolas, and blast furnaces, a
tap hole is opened in the bottom of the furnace, and the molten metal (or
slag) is routed through a series of runners to a ladle. In nonstationary
furnaces such as copper converters and electric arc furnaces, the furnace
is tilted and the molten metal is poured directly into a ladle. In either
case, as soon as the molten metal is exposed to the air, volatile metal
oxides are released from the surface of the stream. As these volatilized
metals move away from the surface in a high-temperature buoyant plume,
they cool and condense to form a very fine metal fume. Again, the buoyant
plume, the fine particle size, and the complex geometry of the release
complicate control.
2.2.4 Hot Metal Transfer and Processing
In the metallurgical operations under study, molten metal is
transported between furnaces or from the furnace to a casting operation in
ladles. These ladles are typically moved by rail or overhead crane. In
some cases, final refining is also accomplished in these ladles. An
example of such refining is ductile iron innoculation in gray iron
foundries.
Both the transport and refining operations are conducted with the
metal still in a high-temperature, molten state. Metals volatilize from
the surface of this molten metal and subsequently condense to form a fine
metal fume. As with .furnace charging and tapping, the buoyancy of the
plume, the fine particulate matter, and the source mobility complicate
control.
19
-------
2.2.5 Metal Casting
Metal casting can be one of the more significant sources of fugitive
emissions in the metallurgical process. Casting processes vary
significantly in different plants. In nonmechanized facilities, the molds
are generally placed in a large, open area. The hot metal ladle is then
moved by an overhead pulley system to the mold, and the casting is poured
and cooled in place. In more mechanized facilities, the mold is placed on
a conveyor and moved to the pouring station and then moved to a cooling
area. Emissions problems are comparable for both mechanized and
nonmechanized processes: the emissions are contained in a relatively
high-temperature, buoyant, moist stream. The constituents of concern are
fine metal oxides that volatize from the hot metal surface. The damp
buoyant stream adds to the difficulty of controlling these sources.12
20
-------
3.0 INDUSTRIAL SOURCES AND FUGITIVE LEAD EMISSIONS
This section describes sources of fugitive emissions characteristic
of several Industries. Because the focus of this document is the primary
and secondary lead smelting industries, these will be discussed first and
in greater detail. Next, fugitive emissions sources for lead-acid battery
manufacturing and gray iron foundry operation will be presented. For each
industry a process description is provided, followed by a description of
fugitive emissions sources.
3.1 PRIMARY LEAD SMELTING
3.1.1 Process Description
Lead is usually found naturally as a sulfide ore containing small
amounts of copper, iron, zinc, and other trace elements. The sulfide ore
is usually concentrated at the mine from'an ore of 3 to 8 percent lead to
a concentrate of 55 to 70 percent lead, containing from 13 to 19 percent
by weight of free and uncombined sulfur. Primary lead smelting includes
four major steps: sintering, reduction, dressing, and refining.
Figure 4 shows a process flow diagram for a typical primary lead smelter.
3.1.1.1 Sintering. The purpose of sintering is to provide a feed
with the proper ratio of lead, silica, sulfur, and Iron for smelting
operations. Additionally, sintering converts metallic sulfides to oxides,
removes contaminants such as arsenic and antimony, and produces a firm
porous clinker that is suitable for blast furnace smelting.15 A sinter
machine consists of a continuous steel pallet conveyor belt up to
30 meters long with perforated or slotted grates through which heated air
is forced. Figure 5 depicts a typical sinter machine. The sinter machine
is charged with lead ore concentrate, recycled sinter and smelting
residues, and adequate sulfide-free fluxes to maintain a sulfur content of
5 to 7 percent by weight. Prior to sintering, the charge materials are
typically fed in controlled amounts onto a common belt conveyor and are
subsequently fed into a crushing machine, and then are moistened and
pelletized. These materials are then split into an ignition portion
(10 percent of total) and a main feed portion (the remaining 90 percent)
and fed into the sinter machine. As the feed material moves through the
machine, it burns, fuses, and cools before dropping off as a cake at the
discharge end of the machine. The sinter then drops through a grating and
21
-------
ro
I line stone
Si Iica
Sinter recyc le
. Flue dust
. Cole
Figure 4. Typical primary lead processing scheme.14
-------
STRONG GAS
TO DEDUSTING
FEED FEED
T
c
RECIRCULATING STREAM
FRESH AIR
FRESH AIR
SINTER'
Figure 5. Updraft sintering with weak gas recirculation.
1S
23
-------
is crushed and screened. The large fraction is conveyed to bins prior to
being charged to the blast furnace. Undersize sinter is recycled through
the sinter machine. If'the smelter has an acid plant, off-gases from the
first 10 meters or so of the sinter machine are drawn off separately for
sulfuric acid recovery. The remaining gas from the sinter machine is
typically routed to a baghouse for removal of particulates in the gas
stream.17-18
3.1.1.2 Reduction. Sinter is reduced to lead bullion in a blast
furnace, which basically is a water-jacketed shaft furnace supported by a
refractory base. Tuyeres, through which combustion air is admitted under
pressure, are located near the bottom and are evenly spaced on either side
of the furnace.
The charge to the blast furnace consists of a mixture of sinter (80
to 90 percent of the charge), metallurgical coke (8 to 14 percent of the
charge), and other materials such as limestone, silica, and recycled
materials. The charge materials are fed into the top of the furnace by
means of either conveyors or dumping from charge cars. Molten material is
continuously tapped from the bottom of the furnace and flows into a
settler. Here, slag and molten lead separate. Most of the impurities are
eliminated in the slag, which includes speiss (arsenic and antimony),
matte (copper sulfide and other metal sulfides), and silicates. The slag
overflows into a granulator, in which water jets break the slag up into
small granules. Granulated slag is transferred to a silo for drying.
From there, a portion with high lead content may be sent by conveyor back
to the sinter plant. Typically, the remainder is transported by truck to
an outside storage pile.
Molten lead flows from the lead-slag separator into a 10- to 20-Mg
ladle, which is transferred by overhead crane to the dressing section.
Typically, emissions from the blast furnace, tapping area, lead ladle, and
slag granulator are cooled and then routed to a baghouse.
3.1.1.3 Dressing. In dressing, the molten lead is cooled to 370° to
430°C (700° to 800°F) in a kettle to allow copper and small amounts of
sulfur, arsenic, antimony, and nickel to collect on the surface as a
dross, which is removed from the solution. This dross, in turn, is
treated in a reverberatory furnace and/or additional kettles to
24
-------
concentrate the copper and other metal impurities before these impurities
are routed to copper smelters for their eventual recovery. Sulfur-bearing
material, zinc, and/or aluminum may be added to the drossed bullion to
reduce its copper content to approximately 0.01 percent. Emissions from
the dressing operation are usually routed to a baghouse.19
3.1.1.4 Refining. The lead bullion is refined in a series of iron
kettles that, typically, are heated with gas-fired burners and stirred
with impellers. Antimony, tin, arsenic, zinc, bismuth, and other
impurities are progressively removed from the molten lead in the refining
kettles. The final refined lead, commonly from 99.990 to 99.999 percent
pure, is then cast for shipment.
3.1.2 Primary Lead Smelting Fugitive Emissions Sources
A summary of potential fugitive emissions sources for primary lead
smelters is provided in Table 4. This list is intended to include all
possible primary lead smelter fugitive emissions sources, and therefore,
may include sources that are not present at a specific facility. In
*
addition, many of the sources listed emit negligible quantities of lead in
comparison to the major primary lead fugitive emissions sources. The
major sources of open fugitive dust emissions include paved and unpaved
roads. The most significant process fugitive sources are sintering and
furnace (blast and reverberatory) leakage and tapping.22 Lead pouring and
transfer in the dressing operation may also be a significant source of
process fugitive emissions at some facilities.
3.1.2.1 Open Fugitive Dust Sources. As stated above, the primary
open fugitive dust sources of lead emissions at primary lead smelters are
paved and unpaved roads. Fugitive emissions from storage piles (materials
handling and wind erosion) are likely to be insignificant in comparison to
road emissions. Estimated quantities of open fugitive dust emissions from
paved roads, unpaved roads and selected storage piles at two primary lead
smelters are summarized in Table 5.
Primary lead smelters generally utilize rail transport of raw and
charge materials extensively within the plant premises. Rail is also used
at some smelters for shipping finished product (lead bullion) and certain
waste products (e.g., blast furnace baghouse dust) offsite. In comparison
to road transport, the use of rail transport reduces the potential for
25
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TABLE 4. FUGITIVE LEAD EMISSION SOURCES FOR A PRIMARY LEAD SMELTERa
1. Vehicle traffic
a. paved roads
b. unpaved roads
2. Ore concentrate storage piles
a. materials handling
b. wind erosion
3. Ore mixing and pelletizing
4. Sinter processing
a. sinter loading
b. sinter machine leakage
c. sinter return handling
d. sinter machine discharge .
e. sinter crushing and screening
f. sinter transfer to dump area
g. sinter product dump area
5. Blast furnace
a. charging
b. tapping
c. leakage
6. Lead pouring to ladle and transfer
7. Slag processing
a. slag pouring
b. slag cooling
c. slag granulator and slag piling
8. Zinc fuming furnace vents
9. Dross kettle
10. Reverberatory furnace leakage
11. Silver retort building
12. Lead casting
Reference 21.
26
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TABLE 5. ESTIMATED OPEN FUGITIVE DUST EMISSIONS AT TWO
PRIMARY LEAD SMELTERS4
Plant Emission source*5
A Paved road 1
Paved road 2
Paved road 3
Paved road total
Unpaved road 1
Unpaved road 2
Unpaved road total
Ore concentrate pile
Baghouse dust pile
Storage pile total
Total for plant
B Paved road 1
Paved road 2
Paved road 3
Paved road total
Unpaved road 1
Unpaved road 2
Unpaved road total
Ore concentrate pile
Sinter pile
Storage pile total
Total for plant
TSP emissions,
Mg/yr
7.16
0.08
0.09
7.33
1.72
0.56
2.28
0.38
0.01
0.39
10.00
7.97
0.25
0.34
8.56
0.31
3.34
3.65
0.08
1.21
1.29
13.50
Lead emissions,
Mg/yr
5.01
0.02
0.06
5.09
0.29
0.01
0.30
0.29
0.01
0.30
5.69
5.41
0.07
0.10
5.58
0.17
0.25
0.42
0.06
0.73
0.79
6.79
^References 23, 24.
"Only the major open fugitive dust sources are listed. Other sources
exist, but are assumed to be negligible.
27
-------
fugitive dust emissions from vehicular traffic significantly. The contact
area between railroad car wheels and rail is much smaller than the contact
area .between tires and road. In addition, the contact surfaces (steel on
steel) are much cleaner for rail than road contact surfaces (tire on
road). The contact surfaces are smoother for rail than road traffic,
resulting in less abrasion. Finally, railcars generally travel more
slowly than road vehicles and thus entrainment due to wake effects is less
for rail travel. The overall effect is that rail traffic entrains much
less material than does a comparable road traffic volume.
In addition to rail, primary smelters make extensive use of conveyors
and cranes to move materials between processes. Using these conveyances
also reduces the need for road vehicle traffic. Overall, plant road
traffic consists of truck transport of raw materials to the plant and of
product and waste materials from the plant. Although some unpaved roads
are found, the main roads used for traffic into and out of the plants are
paved. Vehicular traffic within the plant premises consists mostly of
light pickup trucks and other small vehicles for moving personnel and
vacuum sweeper or water trucks for road dust control. Traffic from these
vehicles is much lighter than traffic from the material haul trucks,
. 25 26
however. '
The roads that are most likely to contribute significantly to
fugitive dust emissions of lead are those associated with lead ore
concentrate storage. Other roads or road sectors that are potentially
significant lead emissions sources are those associated with handling and
transporting baghouse dust. Slag haul roads may also contribute to
fugitive lead emissions.
The materials handling operations that have the greatest potential to
contribute to appreciable fugitive lead dust emissions are the loading and
unloading of lead ore concentrate and baghouse dust. Typically, these
materials are stored in bins inside buildings which reduces the potential
for release to the air. In addition, the moisture content of lead ore
concentrate precludes fugitive emissions to a significant degree. Other
materials with significant lead content include dross and slag. Because
dross is hydrophilic, it remains moist and is not a significant source.
The moisture content of slag at the time of transport to storage (about
28
-------
3 percent) is likewise of sufficient magnitude to prevent significant lead
fugitive dust emissions.
3.1.2.2 Process Fugitive Emissions Sources. The major process
fugitive emissions sources at primary lead smelters are sintering
operations and furnace leakage and tapping.
The sintering operation has several fugitive lead emission sources
associated with it. Conveyor transport of lead ore concentrate, blast
furnace slag, baghouse dust, and other lead-bearing materials can
contribute fugitive lead emissions. Machine leakage can also be a serious
fugitive lead emission source if the machine hood is not well sealed and
not properly maintained. Sinter machine leakage at one primary lead
smelter was reported to be particularly high when blinding (i.e., blockage
of fabric openings) of the acid plant baghouse created backpressure on the
sintering machine. Although the conveyor and sintering machine are
enclosed, and conveyor transfer points and the machine are hooded,
fugitive emissions can still be significant. During an inspection of one
facility, dust piles were observed beneath sinter machine conveyors, at
transfer points, and on structural steel members in the vicinity of the
sinter machine.27 The crushing and screening operations associated with
sintering can also release lead fugitives. Sintering machines, as well as
most process operations at primary lead smelters, are generally located
within open buildings. Fugitive emissions generated by the sintering
process are released to the atmosphere through uncontrolled roof vents and
other building openings.
Blast furnace leakage from the charge conveyor or charge car dumping
can be a significant fugitive emissions source. Fugitive emissions can
also arise from molten lead and slag tapping, slag granulation, and lead
pot transfer operations. Fugitive emissions from dressing operations can
originate from dross reverberatory furnace charging and leakage and from
the transfer of lead to kettles. As mentioned above, these fugitive
emissions are generally released to the ambient air via roof vents, bays,
and other building openings.
29
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3.1.3 Characteristics of Fugitive Dust Sources
In order to estimate fugitive lead emissions from paved and unpaved
roads, representative values for a number of parameters must be deter-
mined. In general, information on vehicle weight, average speed, and road
length is readily available from plant records. Representative values for
surface loading, silt content and lead content must be determined from
road surface material samples, however. Likewise, emissions from
materials handling operations depend upon the moisture content and wind
speed. Table 6 presents data on traffic, surface loadings, silt content,
moisture content, and lead content for samples collected at two primary
lead smelters. As could be expected, paved road silt loadings are highest
for those roads on which lead ore concentrate is hauled (Plant A, road 1,
and Plant B, roads 1 and 2). Overall, paved road dust loadings ranged
from 43.7 to 747 kg/km. Paved road silt content ranged from 27.9 to
90.4 percent; unpaved road silt content varied from 5.11 to
12.2 percent. Although these values can be considered representative,
site-specific data should be collected whenever possible.
Estimating process fugitive lead emissions requires data on lead
content in addition to emission factors. Lead content by weight percent
for a number of process fugitive emissions sources at three primary lead
smelters is presented in Table 7.
4.0 5.0 SECONDARY LEAD SMELTING
5.0.1 Process Description
The principal function of the secondary lead industry is reclamation
of lead from lead-bearing scrap metal. Sources of scrap metal include
scrap batteries from junk dealers, battery plant scrap, and miscellaneous
scrap. Some facilities rely strictly on nonbattery scrap such as wheel
balance weights, pipe, solder, and lead-sheathed cable. Secondary
smelters produce semisoft lead (few impurities), hard or antimonial lead,
and soft lead bullion. Lead produced by secondary smelters is used to
make battery plates, lead oxide, and a variety of miscellaneous items such
as ammunition, pigment, solder, boat keels, and fabricated products.
Currently, 23 secondary lead smelters operate in the United States.
Each of these facilities differs with respect to process configuration and
consequently with respect to fugitive emission sources. Major factors
30
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TABLE 6. TRAFFIC AND ROAD DUST DATA FROM TWO PRIMARY LEAD SMELTERS9
Plant A
Paved road 1
Paved road 2
Paved road 3
Un paved road 1
Unpaved read 2
Plant B
Paved road 1
Paved road 2
Paved road 3
Unpaved road 1
Unpaved road 2
Type of traffic
Ore concentrate transport
Lead product transport
Slag transport
Slag transport
Slag transport
Ore concentrate transport
Lead product transport
Miscellaneous traffic
Ore concentrate transport
Lead product transport
Road
length.
km
0.417
0.094
0.082
0.330
0.249
0.117
0.043
0.133
0.023
0.246
Daily
vehicle
passes
21.7
16.7
3.33
9. OS
5.72
44
16
29
1,6
44
Average
speed, km/hr
8.05
8.05
8.05
8.05
8.05
8.05
8.05
8.05
8.05
8.05
Average
Ho. of
lanes
2
2
2
2
2
2
2
2
2
2
No. of
wheels
18
IB
18
18
IB
IB
IB
18
18
18
Vehicle
weight.
og
41.7
34.5
34.5
34.5
34.5
34.5
41.7
20.5
41.7
34.5
Surface
loading.
kg/ko
747
50.7
110
568
251
43.7
Silt
content.
weight
percent
27.9
33.5
90.4
8.59
6.58
81.7
39.4
87.6
12.2
5.11
Lead
content
of silt.
weight
percent
69.95
21.51
60.93
16.62
0.95
*
67.87
27.36
29.55
56.30
7.61
"References 28 and 29.
-------
TABLE 7. LEAD CONTENT OF FUGITIVE EMISSIONS AT
THREE PRIMARY LEAD SMELTERS3
Source
Lead, weight percent
Plant A
Plant B
Plant C
Ore storage
Return sinter transfer
Sinter storage
Sinter product dump area
Sinter building
Blast furnace
Dross reverberatory building
Lead casting roof ducts
Zinc fuming furnace
Zinc fuming building
37
19
58
31
47
38
3
47
35
51
10
12
22
9
10
Reference 30.
32
-------
that affect these configurations are scrap source, intermediate and final
products, and type of smelting furnace. Table 8 identifies the
23 operating facilities and denotes the number and type of furnaces
operated by these facilities as of 1985. While each of these facilities
is configured uniquely, the same general process flow is applied to most
plants. Figure 6 illustrates a process flow that covers operations at
most facilities. The following paragraphs discuss this general process
and then describe specific process units that can generate fugitive
emissions.
The normal sequence of operations in a secondary lead smelter is
scrap receiving, scrap preparation, charge material storage, smelting,
refining and alloying, and casting. Because batteries constitute the
large majority of scrap material (84 percent by weight in 1989), the
discussion below describes the process when batteries are the primary
source of scrap.
Typically, scrap batteries arrive at the facility by truck. They are
unloaded and stored temporarily in a receiving area. This area may be
open or enclosed. Some secondary lead smelters charge these batteries
whole to the smelting furnace, while others crush and grind whole
batteries and then separate the component parts using a heavy media
float/sink separator. In either case, the acid is drained from the
batteries first. Most plants break or saw scrap batteries open to remove
the lead alloy plates and lead oxide paste and to-drain battery acid.
This operation can be done manually or mechanically. The majority of the
smelters use an automatic feed conveyor system and a slow-speed saw for
removing the covers from recycled batteries. Most facilities also operate
a hammer mill or other crushing or shredding device for breaking battery
cases and covers. Usually, float/sink separation systems are usually used
for separating plastic, lead terminals, lead oxide paste, and rubber. The
majority of the smelters recover the crushed plastic for recycling, and
the rubber cases are landfilled.31*
The lead content of the batteries, which is about 60 percent lead
oxide paste and 40 percent lead alloy plates, is then transferred to the
charge storing and preparation area. Here, the lead scrap is combined
with other charge materials prior to being charged to the smelting
33
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TABLE 8. SECONDARY LEAD SMELTING OPERATIONS IN THE U.S.a
Blast
furnace w
Plant name
Alco Pacific
Chloride Metals
Exide (Dixie Metals)
East Penn
Exide (General Battery)
General Smelting and
Ref i n i ng
GNB
GNB
Gopher
Interstate Lead Co. (ILCo)
Master Meta 1 s
Pacific Chloride Metals
Ref ined Metals
Ref ined Metals
Ross Metals
Roth Brothers
RSR-Quemetco
RSR-Quebetco
RSR
RSR
Sanders Lead
Schuylkill Metals
Schuylkil 1 Metals
Location
Gardena, CA
Tampa , F 1 a .
Da 1 1 as , TX
Lyons Station, PA
Reading, PA
Co 1 1 ege Grove , TN
Frisco, TX
Los Angeles, CA
Eagan, MN
Leeds, AL
Cleveland, OH
Columbus, GA
Beach Grove, IN
Memphis, TN
Rossvi Me, TN
Syracuse, NY
Indianapol is, IN
City of Industry, CA
Middletown, NY
Dallas, TX
Troy, AL
Mound City, MO
Baton Rouge, LA
No.
2
1
1
2
1
1
1
1
1
2
1
1
1
1
1
1
APOD"
FF
FF
FF
FF/VS
FF
FF
FF
FF
FF
FF
FF
FF
FF
FF
FF
FF
Reverb/
rotary
No. APCD°
lc FF/TS
1 FF
2 FF/VS
1 FF
2 VS
1 FF
1 FF
1C FF
1 FF
1 FF/TS
1 FF
1 FF
Kettle
furnace w
No.
5
5
5
2
10
3
6
3
5
5
8
5
7
6
NA
6
7
6
6
6
3
6
APCD"
FF
VS
FF
FF
FF
FF
FF
FF
FF
FF
FF
VS
FF
FF
FF
FF
FF
FF
FF
VS
FF
FF
'Reference 32.
DAir pollution control device (APCD):
venturi scrubber.
cRotary furnace.
FF = fabric filter; TS = tray-type scrubber; VS =
34
-------
CO
en
Oiides. flur
dust. mi«rd
scrap
B.itlrrip<.
Pure Strap
Drosses.
residues.
oversije
scrap
Residues.
die scrip.
lead sheathed
cable and
ui re
High lead
content
scrap
I lues tone
Recycled dust
Coke
Slaq residue
lead oOdes
Scrap iron
Rerun slaq
Figure 6. Typical secondary lead smelting and refining scheme.33
-------
furnace. Other lead-bearing materials charged to the smelting furnace are
slags from the smelting furnace, drosses from the refining kettles, and
flue dust collected by the facilities' air pollution control systems.
Other charge materials include coke, which is used as a heat source and
reducing agent, and limestone, sand, and scrap iron, which are used as
fluxing agents.
Secondary lead smelters charge these raw materials to one of three
types of furnaces—blast, reverberatory, or rotary. The various
configurations used are described more fully in Section 3.2.1.3. Each of
these three furnace types produces three primary discharge streams—the
lead product or intermediate, slag, and an exhaust gas stream that
contains a high concentration of flue dust. All operating smelting
furnaces use a fabric filter or wet scrubber to control particulates.
Because both the slag and the flue dust collected by the air pollution
control system contain high concentrations of lead, most facilities
recycle them to the furnace for further recovery. Slag also may be
transported to an onsite or offsite landfill for disposal. The lead
products from the smelting furnace are refined and alloyed as necessary in
kettle furnaces. The product from the kettle furnaces is pumped to the
casting machine and cast to lead ingots.
The subsections below provide additional information about specific
process components. The first two describe storage and handling
operations and raw material/charge preparation areas, respectively. The
third subsection describes smelting operations, and the final subsection
describes refining and casting operations.
3.2.1.1 Storage and Handling Operations. Secondary lead smelters
routinely handle and store substantive quantities of raw materials and
recycled by-products from the smelting and refining furnace. Materials of
greatest concern relative to fugitive lead emissions are streams that have
high concentrations of lead, particularly those that also tend to have
high levels of fines. Major streams of interest include the lead alloy
plates, lead posts, and lead oxide paste from the battery breaking units
as well as recycled slag, refining kettle drosses, and flue dust.
Although no data have been found to support the assertion, the lead oxide
paste (when dry), drosses, and flue dust are reported to have particularly
large quantities of fines.
36
-------
No information was found to characterize the handling and storage
practices of these materials across the secondary lead smelting
industry. However, limited studies of the characterization and control of
fugitive emissions at specific facilities suggest that practices vary
across the industry.35'38 For example, scrap lead transport from the
battery breaker to the charge material storage area via both conveyor
systems and front-end loaders has been reported. Typically, slag
materials are transported in slag buckets by either forklift or front-end
loader. Dross materials generally are collected from the refining kettle
and placed in 55-gallon drums or tote boxes. These containers are
transported from the refining area to the charge storage area by forklift
and front-end loader. Finally flue dust may be collected in drums and
hauled to the storage area or may be transported directly to storage via a
mechanical conveyor system. While these systems vary from plant to plant,
two elements are common to all facilities. First, all of the transport
mechanisms have the potential to spill lead-bearing materials onto floors
or external surfaces. Second, most vehicular traffic appears to be on
open yards (paved or unpaved) and on enclosure floors rather than on well-
defined roads.
Storage practices also appear to vary from plant to plant. Charge
materials may be stored in partially or totally enclosed buildings or they
may be stored outdoors. Typically, storage piles or three-sided storage
bins are used to store slag and scrap. Dross and flue dust may be stored
in bins or in the vessels (drums or boxes) in which they are collected.
3.2.1.2 Charge Material Preparation. All secondary lead smelters
blend a combination of raw and recycled lead-bearing materials with
fluxing agents and coke to obtain the smelting furnace charge. A
preliminary step practiced at most smelters is a battery breaking/
separation process. Another preliminary step practiced at a few foundries
is flue dust agglomeration. Both of these processes are reviewed briefly
in the paragraphs below.
No general survey of battery wrecking practices employed across the
secondary smelting industry has been identified. The available literature
suggests that practices vary considerably from plant to plant. However,
most plants use some type of crushing, grinding, or cutting process to
37
-------
separate the lead-bearing components from the polypropylene or hard rubber
cases. Common features of these systems are:
1. Mechanically breaking or crushing the batteries;
2. Separating the acid from the solids;
3. Separating the lead-bearing portions from the cases and
separators;
4. Greatly reducing manual labor; and
5. In some processes, separating metallic lead from the lead
compounds.39
In plants that use cutting operations, the casings typically are
processed further with a hammermill, and lead-bearing materials are
separated from the casing by flotation methods. In general, wrecking
operations are performed with closed equipment to limit worker exposure to
acid splashes. The procedures are also performed in a wet environment and
tend to be conducted within buildings. All of these factors limit fugitive
lead emissions from these processes.
Flue dust handling has historically been a serious problem to
secondary lead smelters in the United States and other parts of the
world. Flue dusts generated by secondary lead blast and reverberatory
furnaces contain appreciable amounts of lead. The collection, handling,
storage, and reintroduction of this dust to the smelting process Involves
opportunities for release of the dust to the workplace and ultimately to
the ambient air. The flash agglomeration furnace appears to be an
effective means of reducing emissions from the handling of flue dust
beyond the point of its collection in a baghouse. Usually, when an
agglomeration furnace is used, a screw conveyor system is employed to
transport the flue dust from the baghouse to the agglomeration furnace
charge system. The agglomeration furnace then melts the flue dust into a
slag-like material that can be handled in bulk form and reintroduced to
k 0
the process without generating an appreciable amount of dust.
3.2.1.3 Smelting Furnace Operations. Secondary lead smelters employ
one of four types of smelting furnace configurations—blast furnace only,
blast furnace/reverberatory furnace combination, reverberatory furnace
only, or rotary furnace only. Table 8 shows the distribution of these
configurations across the industry. The processes associated with each of
these scenarios are briefly described below.
38
-------
3.2.1.3.1 Blast furnace only. A simplified flow diagram of a single
secondary lead blast furnace system was presented in Figure 2. A blast
furnace is a vertical unit and is charged through a door at or near the
top of the furnace. The blast furnace charge material consists of a
mixture of battery plates, lead oxide paste, drosses from refining
kettles, flue dust, rerun blast furnace slag, coke, limestone, sand, and
scrap iron. Coke is used as a reducing agent as well as a primary source
of heat, while the lead-free materials are used as fluxing agents. Air or
oxygen enriched air is "blasted" into the furnace through tuyeres near the
base.
As the charge material melts, the iron, silica, and limestone form an
oxidant-retardant flux that floats to the top of the melt. Molten lead is
tapped almost continuously and cast into large blocks called "buttons" or
"sows," each of which weighs about 0.9 Mg (1 ton). When battery scrap is
being charged, approximately 70 percent of the charge material is tapped
off as hard (or antimonial) lead, which may contain as much as 12 percent
antimony and 2 to 3 percent arsenic. Approximately 7 percent of the
charge leaves the furnace as dust; 18 percent of the remaining material is
tapped as slag and matte. The blast furnace flue dust and approximately
5 percent of the blast furnace slag are recycled to the furnace. A
typical range for blast furnace production is 18 to 73 Mg/day (20 to
80 tons/day).
Typically, furnace emissions are controlled by an afterburner, U-tube
coolers, and a baghouse. Frequently, knockout boxes are used to collect
large particulate matter that separates from the gas flow in the ducts.
Furnace emissions are discharged to the atmosphere through a stack.
Charging, slag tapping, and lead tapping operations may be hooded and
ducted to the process baghouse or to a separate sanitary baghouse for
recovery of lead-containing particulate matter.
3.2.1.3.2 Reverberatory or rotary furnace only. A simplified flow
diagram of a secondary lead smelter system with a single reverberatory
furnace system was presented in Figure 3. The reverberatory furnace uses
gas- or oil-fired burners. The charge material is heated by radiation
from the flame and from the furnace walls. As indicated in Figure 3, the
reverberatory furnace charge material typically includes lead scrap,
39
-------
battery plates, lead oxides, and recycled flue dusts. Charge materials at
a few secondary smelters include whole batteries including their crushed
polypropylene cases. Charge material is added as more of the solid
material in the furnace becomes liquid. The reverberatory furnace
operates at a temperature of about 1260°C (2300°F), near atmospheric
pressure. Molten metal (i.e., semi soft lead containing 0.3 to 0.4 percent
antimony and less than 0.05 percent arsenic) is tapped into molds
periodically as the level rises in the furnace. Reverberatory furnaces
produce purer lead than blast furnaces. As a result, alloying agents
contained in the feed material are concentrated in the reverberatory
slag. Smelters that operate a reverberatory furnace either recycle the
slag to a blast furnace or sell the slag for minor metal recovery.
Typically, a reverberatory furnace produces about 45 Mg/day (50 tons/day)
of lead. Approximately 47 percent of the input material is recovered as
lead, 46 percent as slag, and 7 percent leaves the furnace as particulate
and metal fume.
The rotary furnace, which is similar to the reverberatory furnace, is
used primarily in Europe and is less common in the United States. The
rotary furnace is a batch feed unit that rotates slowly during heating of
the charge material. A major difference between the rotary furnace and
the reverberatory furnace is that about 70 percent of the sulfur contained
in the rotary furnace charge material is removed in the slag. Relatively
large amounts of iron (9 to 10 weight percent of the feed) in the rotary
furnace feed promote this removal. Iron serves two distinct purposes:
(1) it promotes the reduction of lead sulfate and lead oxide to metallic
lead, and (2) it complexes with most of the available sulfur and
eliminates the sulfur in the slag.
Generally, furnace emissions are controlled by an exhaust gas
settling chamber, U-tube coolers, and a baghouse. Charging, lead tapping,
and slag tapping operations are typically hooded and ducted to a separate
baghouse.
3.2.1.3.3 Blast/reverberatory furnace combination. Plants that have
both blast and reverberatory furnaces feed different raw materials to the
two furnaces to produce lead with different specifications. By using both
types of furnaces, a secondary lead smelter can produce a maximum amount
40
-------
of fully refined pure lead and at the same time promote maximum recovery
of antimony, arsenic, and tin in a high-antimony bullion. Reverberatory
furnaces are often used to maximize pure lead production by reducing the
lead compounds in the feed material to metallic lead and concentrating the
oxidized alloying agents in the slag. Reverberatory furnaces reclaim lead
from flue dust (generated from either blast or reverberatory furnaces)
more efficiently than blast furnaces because reverberatory furnaces are
able to use the dust with smaller losses in capacity and less
reentrainment. The high-alloy slag produced by the reverberatory furnace
is effectively used by the blast furnace to produce antimonial lead
alloys.
Typical feed material compositions used when operating both a blast
and a reverberatory furnace are illustrated in Table 9. When a facility
operates both blast and reverberatory furnaces, the feed materials charged
to each furnace differ from those materials used when smelting is
conducted using only a single furnace type. Lead is. fed to the
reverberatory furnace in the form of crushed batteries, battery plates,
and flue dusts, while lead is fed to the blast furnace in the form of
drosses and reverberatory slag. The feed to both furnaces has a lead
content of about 70 percent by weight.
3.2.1.4 Refining and Casting Operations. Refining and alloying are
done in pot furnaces (refining kettles). The process is a batch operation
and may take from a few hours to 2 to 3 days, depending upon the degree of
purity or alloy type required. Refining kettles are gas- or oil-fired
with typical capacities of 23 to 136 Mg (25 to 150 tons) lead. Refining
and alloying activities are conducted at temperatures ranging from 320° to
700°C (600° to 1300°F).
Following the final refining step, a sample of the refined metal is
collected, and the alloying specifications are verified by chemical
analysis. When the desired composition is reached, the molten metal is
pumped from the kettle into the casting machine and cast into lead ingots,
rectangular bars that weigh approximately 25 kg (56 Ib) each.
41
-------
TABLE 9. FEED MATERIALS AND FURNACE PRODUCTS, REPORTED BY
ONE PLANT WITH A BLAST/REVERBERATORY COMBINATION3
Weight percent
of feed
Blast furnace
Inputs
Iron 7
Sand 3
Limestone 3
Drosses 15
Reverb slag . 60
Recycle slag 7
Coke 5
100
Outputs
Raw metal 56
Slag and matte . 20
Flue dust 5
Reverberatory furnace
Inputs
Crushed batteries 39
Battery plates 35
Flue dust - blast furnace 19
Flue dust - reverb furnace 7
Outputs
Raw metals 70
Reverb slag 18
Flue dust 7
Reference 41.
42
-------
3.2.2 Secondary Lead Smelting Fugitive Emission Sources
Table 10 provides a comprehensive listing of all fugitive emission
sources that potentially may be found in a secondary lead smelter. As
discussed in Section 3.2.1, process operations are unique to each
smelter. Consequently, all of the sources listed in Table 10 will not be
found at all secondary lead smelters. Further, as indicated in Table 10,
many of the sources are expected to contribute only negligible quantities
of lead emissions at most facilities. However, they were included in the
listing to ensure completeness of review. The two major categories of
sources are open fugitive dust sources and process fugitive sources. The
subsections below describe the sources within each category that are
likely to contribute substantively to fugitive lead emissions.
3.2.2.1 Open Fugitive Dust Sources. The primary open dust source of
fugitive emissions at secondary lead smelters is expected to be vehicular
traffic. Available information suggests that furnace charge materials,
intermediate metal ingots or buttons, waste materials, and final product
are transported throughout the plant via front-end loaders and
forklifts. These transport activities occur in open yards and in areas
that are fully or partially controlled. In-plant vehicular transport of
materials contributes to fugitive emissions in two ways. First, during
transport, some of the lead-bearing materials typically spill or leak from
the transport vehicles and settle on floors and yards. Second, the
traffic contributes directly to lead emissions by entraining lead-bearing
particles that are deposited on travel surfaces.
The second major source of vehicular emissions is the truck traffic
associated with scrap receipt and product shipments. Typically, shipping
and receiving trucks follow well-defined traffic patterns on plant
roads. Available data suggest that these roads generally are paved, but
in some cases they may be unpaved.43'*5 Lead-bearing materials deposited
on roadway surfaces will be entrained by truck travel on the roads.
Typically, lead-bearing materials such as lead scrap, recycle or
waste slag, flue dust, and dross are stored in secondary smelters. They
may be stored in bins or piles, and the storage area may be fully or
partially enclosed or completely unenclosed. All of these streams contain
significant quantities of fine lead-bearing materials that may be emitted
43
-------
TABLE 10. FUGITIVE EMISSION SOURCES IN SECONDARY
LEAD SMELTERS3
Open dust sources
• Vehicular traffic
— Raw material delivery trucks
— In-plant material transfer (open area)
— General plant traffic
• Material storage bins/piles
~ Unprocessed batteries
-- Scrap lead
— Recycle slag
-- Dross
— Recycled flue dust
-- CokeD
— Limestone
- Sand5
-- Iron scrap
-- Waste materials (slag, flue dust)
Process sources
• Battery wrecking unit
• Agglomeration furnace
• Blast, reverberatory, and rotary furnaces
~ Charging
— Lead tapping
-- Slag tapping
— Slag cooling
• Kettle furnace
~ Charging
— Refining (softening and alloying)
— Dross skimming
~ Tapping
• Casting5
^Reference 42.
These sources are considered to be negligible sources of lead
emissions.
44
-------
via disturbances during load-in and load-out or by wind erosion. The
potential for emissions is related inversely to the degree to which stored
materials are contained and to the "wetness" of the material being stored.
3.2.2.2 Process Fugitive Emissions Sources. Generally, the process
fugitive emission sources that can generate substantial quantities of lead
emissions are associated with furnace operations. The lead emission
potential of anciliary operations such as lead casting and battery
wrecking is considered to be negligible.
The primary exhaust streams from the smelting furnaces are vented
directly to an air pollution control device. Hence, these emissions are
not considered to be fugitive. However, lead emissions from charging and
lead and slag tapping of blast, reverberatory, and rotary furnaces can be
substantial. These furnaces may be charged by either a charge bucket type
system or a mechanical conveyor system. Regardless of the type of system
used, the charge materials contain fine lead-bearing dust that can be
liberated during charging operations. Another problem reported at some
facilities is spilling of fines around the charging door. These fines
settle on horizontal surfaces around the furnace, from which they are
subsequently entrained by wind and ventilation air. The emissions from
tapping operations and slag cooling are principally metal fumes from hot
furnaces.
Unlike the smelting furnaces, exhaust from agglomeration furnaces and
kettle refining furnaces is not necessarily ducted directly to air
pollution control systems. The agglomeration furnace can emit dust during
charging operations. Both types of furnaces are also potential sources of
lead fume emissions during normal operations and during charging and
tapping operations.
3.2.3 Characteristics of Fugitive Dust Sources
The information presented in Section 2.1 suggests that the quantity
of emissions from paved and unpaved roads depends on traffic character-
istics and on the chemical and physical characteristics of emitting road
surfaces. The traffic characteristics of concern include the number of
lanes, average vehicle speed, weight and number of wheels, and the
industrial augmentation factor described above. Most of this information
is available from plant records. Emissions from vehicular traffic also
45
-------
depend on the silt content, surface dust loading, and lead content of
material deposited on the road surface. Emissions from storage and
handling operations depend on average wind speed, moisture content, and
lead content of the material stored. Emissions due to wind erosion are a
function of silt and lead content of the material stored, in addition to
meteorological factors such as the number of wet days and percentage of
time the wind speed is above 5.4 m/sec. Table 11 presents data reported
in the literature on the lead content of materials and surface dusts.
Table 12 presents data on dust, silt, and lead loadings at a secondary
lead smelter from a more recent study. Ideally, the lead concentration in
the silt should be used in emission calculations. However, only total
lead content was reported in the literature. Use of total lead content
should still yield a reasonably accurate estimate. Only limited data were
obtained on silt content and travel surface dust loadings. During the
more recent study referenced above, data on silt content were obtained
from eight locations in a single smelter. The silt content for these
eight locations ranged from 20 to 33 percent, with an average of
24 percent. This same study reported total dust loadings in the range of
10 to 50 g/m2, with an average of 28 g/m2. Another study reported than
the silt content on a plant access road was 15 percent, with a total dust
loading of 20 g/m2.
3.3 LEAD-ACID BATTERY MANUFACTURING
3.3.1 Process Description**8
The production of lead-acid batteries consists of four main steps:
grid casting, paste mixing, three-process operation, and formation. In
addition, many battery manufacturers produce lead oxide and reclaim lead
scrap. Small manufacturers generally purchase lead oxide from an outside
producer and send lead scrap to a smelter for recycling, however. Each of
the main steps for lead-acid battery production is described below. Also
described are lead oxide production and lead reclamation. A process flow
diagram for a typical lead-acid battery manufacturer is provided in
Figure 7.
3.3.1.1 Grid Casting. In the grid casting process, lead alloy
ingots are melted in an electric or gas-fired pot and then poured into
molds. Typically, grids are cast in pairs. However, continuous casting
46
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TABLE 11. LEAD CONTENT OF SECONDARY LEAD SMELTER MATERIALS*
Lead content, percent No. of
Material Range Average observations
Flue dust 15-56 36 4
Drosses 27-74 51 7
Road dust 26-50 34 4
Battery scrap 44 1
Reference 46.
47
-------
TABLE 12. RESULTS OF ROADWAY DUST LOADING SAMPLING AT A SECONDARY LEAD SMELTER"
Size description
Outgoing path.
near main-
tenance building
In front of truck
•calet
Outgoing path
Outgoing path.
furtheat from
wheelwaeh
Incoming path
Incoming path
Partially in
incoming path
Noer guardhouee
Weighted
averagea
Sample
No.
6
1
a
4
3
10
1
a
Avg.
Control atrateoy
Areaa not hoaed
Dual
loading,
g/aq. m.
60.1
36.6
33.3
31
30.6
17.6
12.6
9.66
27.7
Pb
loading.
g/aq. m.
19.0
4.04
8.64
8.23
8.73
6.68
1.78
2.78
7.36
Silt
content.
percent
22.1
24.1
24.7
19.8
23.3
31.2
22.7
32.6
23.8
Control atrateov
Areae hoeed
Sample
No.
7
8
Avg.
Duet
loading.
g/aq. m.
13.8
6.64
10.4
Pb
loading.
g/aq. m.
1.96
2.23
2.09
Silt
content.
percent
36.3
34.8
36.2
Sample
No.
12
Avg.
Control strategy
Areaa power waahod
Duat
loading.
g/aq. m.
2.92
2.92
Pb
loading.
g/aq. m.
1.09
1.09
Silt
content.
percent
33.3
33.3
Control atraleOY
Areaa vacuumed and hoeed
Sample
No.
11
A»g.
Duat
loading.
g/aq. m.
4.O6
4.06
Pb
loading.
g/aq. m.
0.976
O.976
Silt
content.
percent
29.2
29.2
-p.
co
"Reference 47.
-------
4 t
1 PARTICULATE 1 PARTICULATE
j MATTER {MATTER
r~ '
^ G
ACID -f-
FRESH
ACID
LEAD OXIDE LEAD PASTE
PRODUCTION MIXING
1 PARTICULATE
{MATTER
*
! PARTICULATE
1 MATTER
— ~i r~ ~\
RID CASTING fc GRID
FURNACE CASTING
„ «RID PLATE PLATE ELEMENT ^
PASTING STACKING BURNING ASSEMBLY
GRID CASTING OPERATION THREE PROCESS OPERATION
4
ISULFURIC
JACIO MIST
* FORMATION — R'NS'NG
• r-UNMAiiuN -•> ANO ORY|NO
•»
1 SULFU
J ACID 1
ASSEMBLY INTO _^ FORMATION
BATTERY CASE
n
— »| ACID |
ASSEMBLY INTO
*" BATTERY CASE \
\
\ .. WASH ANO ^ SHIPPING
/ PAINT
illST /
AGIO BOOST _/
REFILL CHARGE
STREAM
Figure 7. Process flow diagram for storage battery production.
49
-------
machines are also found. After the grids have solidified, they are
ejected from the molds, trimmed, and stacked.
3.3.1.2 Paste Mixing. Paste mixing is a batch process. Lead oxide,
water, and sulfuric acid are added to a mixing machine to form a stiff
paste. To make a negatively charged paste, expander is also added.
Mixers are water-jacketed or air-cooled to prevent excessive temper-
atures. The paste may be positively or negatively charged, depending upon
the amounts of water, sulfuric acid, and expander used in the mix.
Positive paste has slightly more sulfuric acid and less water than the
negative paste and uses no expander. After mixing, the paste i-s applied
to the grids, flash dried, stacked, and cured.
3.3.1.3 Three-Process Operation. The three-process operation
consists of plate stacking, burning, and assembly of elements in the
battery case. Plates are first stacked in alternating positive and
negative order, separated by insulators. Burning consists of connecting
the plates by welding leads to the tabs of each positive and negative
plate. The completed elements are then assembled in the battery cases
either before formation ("wet" formation) or after formation ("dry"
formation). An alternative to this operation is the "cast-on-strap"
process in which molten lead is poured around the plates and tabs to form
the connection.
3.3.1.4 Formation. The formation process chemically converts the
inactive lead oxide-sulfate paste into an active electrode. The unformed
plates are placed in a dilute sulfuric acid solution, the positive plates
are connected to the positive pole of a direct current (dc) source, and
the negative plates are connected to the negative pole of the dc source.
The formation process may be wet or dry. In the wet formation process,
the elements are assembled in the case before forming. In the dry
process, the elements are formed in a tank of sulfuric acid and then
assembled in the case.
3.3.1.5 Lead Oxide Production. Lead oxide is produced by either the
ball mill process or the Barton process. In the ball mill process, lead
ingots are tumbled, forming lead oxide on the surface. Lead oxide dust
and unoxidized lead particles are drawn off by a circulating air stream.
Larger particles are further ground in a hammermill. The lead oxide and
50
-------
metallic lead particles are then conveyed to storage bins. Operating
parameters are controlled to maintain a specified oxide to metallic lead
ratio.
In the Barton process, molten lead is rapidly stirred and atomized in
a pot. The lead droplets are oxidized by an air stream, then conveyed to
a cyclone and then to a fabric filter. The larger particles captured by
the cyclone are then ground in a hamrnermill and conveyed to the fabric
filter.
3.3.1.6 Lead Reclamation. Battery manufacturers often reclaim lead
scrap. "Clean" lead scrap is charged to a pot-type furnace and recast
into pigs for use in the battery manufacturing process. The reclamation
of lead scrap is not typically a continuous process, but rather it is done
only when a sufficient quantity of scrap has accumulated.
3.3.2 Fugitive Emissions Sources
Unlike primary and secondary lead smelters, lead-acid battery
manufacturing plants are typically enclosed. Because the battery
manufacturing processes do not require the high temperatures of smelting
operations, dissipation of heat to maintain a safe working environment
(and thus satisfy OSHA requirements) is much less of a problem for battery
manufacturing plants than for smelters* Thus, enclosure is less likely to
be cost-prohibitive for battery plants than for smelters.
In order to maintain OSHA requirements for ambient lead concentration
in the work area, facility enclosure requires tight control of fugitive
emissions. Grid-casting, paste mixing, and three-process operation are
typically hooded or vented, and large overhead plenums combined with
grated floor intakes are often provided in work areas to minimize worker
exposure to lead particulates. Further, lead oxide production facilities
are specifically designed to capture metallic lead and lead oxide
particles. (Lead emissions from the formation process are negligible.)
Although plants may operate with open bays or doors, the ventilation
systems generally ensure movement of air into open doors and out through
the ventilation intakes and ducts. Further, ventilation systems generally
include control devices. These, and other typical control devices at
lead-acid battery manufacturing plants, are listed in Table 13.
51
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TABLE 13. LEAD-ACID BATTERY MANUFACTURING—TYPICAL CONTROL DEVICES
Process
Typical control device
1. Grid casting
2. Paste mixing
a. Charging
b. Mixing
3. Three-process operation
4. Lead oxide production
5. Lead reclamation
Scrubber (impingement, cascade)
Fabric filter
Uncontrolled
Fabric filter
Scrubber (impingement)
Fabric filter
Scrubber (impingement)
Mechanical collector (e.g., cyclone)
followed by baghouse
Scrubber (impingement, cascade)
Fabric filter
Reference 57.
52
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Nonprocess fugitive lead emissions at a typical lead-acid battery
manufacturing plant are most likely to result from the transfer and
storage of lead oxide. Plant enclosure and OSHA requirements necessitate
good housekeeping practices that minimize reentrainment of lead oxide
dust, however. Many plants are now equipped with central vacuum systems
that are used to collect lead oxide dust from floors and work areas.
Other dust control measures include wetting floors in the paste-mixing
area and using oil-based sweeping compounds. When lead oxide is purchased
from another facility, it is typically transported in sealed tanks and
conveyed by pipe directly into storage silos without exposure to the plant
environment. On some occasions pipe connections may fail, resulting in a
release of lead oxide to the plant environment. However, this is not a
routine occurrence and thus is considered an upset.
In summary, both process and nonprocess fugitive emissions are minor
at most lead-acid battery manufacturing plants. The combination of plant
enclosure and good housekeeping practices result in the prevention of any
significant fugitive emissions from these facilities.
3.4 GRAY IRON FOUNDRIES
3.4.1 Process Description58
The iron foundry industry uses iron and steel scrap to manufacture
cast-iron products ranging in size from a few grams to several megagrams
per casting. Many of the processes involved in producing castings can
potentially release gaseous and/or particulate fugitive emissions to the
foundry environment and subsequently to the external atmosphere.
The typical iron foundry processes various grades of iron and steel
scrap to produce iron castings. Generally, any foundry that produces
gray, ductile, or malleable iron is considered an iron foundry. This
classification is reasonable in that most processes used to produce the
three types of iron are identical. Also, the chemical specifications for
gray iron are very similar to those for ductile and malleable iron.
The four basic operations present in all foundries are: raw
materials handling and storage, melting, pouring of metal into molds
(i.e., casting), and removing castings from the molds. Other operations
present in many but not all foundries include: (1) preparation and
assembly of molds and cores; (2) mold cooling; (3) shakeout; (4) casting,
53
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cleaning, and finishing; (5) sand handling and preparation; and (6) hot
metal inoculation.
For the purpose of the following discussion, the iron foundry has
been divided into five areas of operation:
1. Raw materials storage and handling;
2. Melting and casting;
3. Cleaning and finishing;
4. Mold and core preparation; and
5. Waste handling.
A general flow diagram of foundry operations is presented in Figure 8 and
a block diagram of core and mold making is presented in Figure 9. Note
that while most iron foundries have operations falling into each of the
broad categories listed above, the foundry industry is so diverse that
specific operations vary greatly from plant to plant. Described below are
the operations most commonly utilized in iron foundries.
As can be seen in Figure 8, raw materials enter the foundry in one of
two areas: the melt shop or the core- and mold-making area. At the melt
shop, the primary raw materials are iron scrap, borings and turnings,
limited quantities of pig iron and foundry returns used for metallic
content, coke for cupolas and fluxing material such as limestone,
dolomite, fluorspar, and calcium carbonate. The metal!ics are generally
melted in one of three furnace types: cupola, electric arc, or electric
induction. After the iron is melted, required ladle additions are made,
either in the furnace or the ladle, and the iron is transferred by ladle
to the pouring area for casting in molds.
Upon reaching the casting area, the hot metal is poured into a mold
to produce an iron casting. The four types of molding processes that have
received the most attention are green sand molds, shell sand molds, cold
set molds, and permanent molds, or centrifugal casting. Of these, green
sand molding is by far the most prevalent. If a sand mold is used, the
mold and casting are then transferred to a shakeout area, where the
casting is removed from the sand. The spent sand is then recycled, and
the casting is taken to the finishing shop for cleaning, grinding, and
finishing.
54
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cn
cn
UNDER
SAND
oo I oo oo1—'oo
f2At I @
V
UNDER
STORAGE
TANK
SANO
SIORAGf
IAP4R I >l*.jnr*\js
MOLD I \ "N /
BINDER] \^
CORl & MOLD MAKING ASIA
(ie« figo.. 2-3)
SAND STORAGE
CORE BINDER (fj) (g)
i-Plirnrm -»• a pi a *'
UNDER STORAGE
(MISSIONS
CASTINGS
SHIPPING
I
Figure 8. Composite flow diagram for the gray Iron foundry industry.
(Numbers refer to source listings in Table 2-2.)
-------
Sand and
3ino»n
Chemical
Catalyst
Figure 9. Mold and core making.
60
56
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Further descriptions of the specific foundry operations are included
in the following section on sources of iron foundry fugitive emissions.
3.4.2 Fugitive Emissions Sources
Iron foundries contain a variety of process sources with the
potential for emitting particulate air pollutants including lead to the
plant environment and on to the atmosphere. Specific operations differ
greatly in different foundries. Hence, the specific operations that
present an emissions problem in one foundry may not be a problem in
another foundry. Based on discussions with industry personnel, probable
sources of fugitive emissions were identified and are presented in
Table 14. Those fugitive sources that have the greatest potential to be
major sources at a specific plant are so signified in Table 14. Each of
these sources is discussed briefly below.
Raw materials are used in two areas of the foundry. Metal!ics, and
sometimes coke, and some type of fluxing material are needed to produce
molten iron in the melt shop. Sand and binders or a prepared mixture of
sand with binders is needed for mold and core preparation. Depending upon
the method used, both the storage and handling of these materials may
become a fugitive emissions problem. However, appropriate processing and
storage methods should minimize emissions. Also, only the metallic
materials are expected to be sources of lead emissions.
The operations that occur in an iron foundry from the time scrap is
charged into a furnace for melting until the time the casting is to be
removed from the mold represent the greatest potential for lead fugitive
emissions. Most iron castings are produced from scrap that has been
melted in a cupola, an electric arc furnace (EAF), or an electric
induction furnace. The primary fugitive emission sources from melting are
(1) cupola tapping, (2) the total EAF cycle, and (3) induction furnace
charging and melting. Other major emission sources in this area include
(1) inoculation of ductile iron, (2) pouring hot metal into molds, and
(3) cooling the filled molds before shakeout.
The cupola furnace is an upright, brick-lined, cylindrically shaped
vessel that uses the heat from the charged coke to melt iron. The cupola
operation is continuous, with metallics, coke, and fluxing agents charged
in layers at the top and the molten iron tapped from the bottom. Because
57
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TABLE 14. FUGITIVE EMISSION SOURCES IN IRON FOUNDRIES1
Source
No.fa
Source identification
Pollutant
Part icu late
Lead
Potentially
significant
source
Raw material storage and handling
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Melting
16
17
18
19
20
21
22
23
24
25
26
Limestone handling
Unloading
Transfer to storage
Storage
Transfer to furnace
Coke handling
Unloading
Transfer to storage
Storage pile
Transfer to furnace
Metallic charge handling
Unloading
Storage pile
Transfer to furnace
Binder unloading
Binder storage
Sand unloading
Sand storage
and casting
Cupola furnace
Tapping
Charging
Electric arc furnace
Charging
Leakage
Tapping
Induction furnace
Charging
Melting
Tapping
Iron inoculation
Pouring
Cooling
X
X
X
X
X
X
X-
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
(continued)
58
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TABLE 14. (continued)
Potentially
Source Pollutant significant
No. Source identification Particulate Lead source
Cleaning and finishing
27 Shakeout X X
28 Return sand system X
29 Cooling and cleaning X
30 Grinding XX X
Mold and core preparation
31 Sand charge to mixer/muller X
32 Dry sand mixing or mulling X
33 Holder
34 ' Cold set mold
35 Oven bake core box X
36 Core oven leakage
37 Shell or hot box heat
38 Cold box core or mold
39 No bake core box
40 Core cooling
41 Core wash X
Waste handling
42
43
44
45
46
Slag quench
Waste sand transfer
Waste material storage
Transfer to landfill
Baghouse catch
X
X
X
X
X
^Reference 61.
Sources are identified by number in Figure 8.
59
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the cupola is kept under negative pressure for emission control purposes,
charging is generally not a fugitive emissions problem. The only source
of fugitive emissions is the tapping of the molten metal from the
furnace. The metal is tapped in one of two ways. In the first method,
the metal is tapped to a forehearth, where the slag is skimmed, and then
the iron is transferred into a ladle for pouring. In this case, the slag
skimming and transfer into the ladle are minor sources of fine particulate
emissions. In the other method, the metal is tapped directly to a ladle
and the slag is skimmed from the ladle. This is also a minor source of
fine particulate emissions.
The EAF Is a refractory-lined, cup-shaped vessel with a refractory-
lined roof. Three graphite electrodes are placed through holes in the
roof to provide the electrical energy for melting iron. The EAF can be
charged through the side; or the roof can be removed and the furnace
charged from the top. Most newer and larger furnaces are of the top-
charge variety. Primary emission control for the EAF during melting is
generally accomplished through some form of direct shell evacuation (DSE)
or by the use of a canopy hood. However, the DSE system does not operate
when the roof is removed for charging or tapping, both of which may be
significant sources of fugitive particulate and lead emissions.
Malfunction or inferior design of the primary DSE system also can lead to
significant fugitive emissions problems. In the case where a canopy hood
is used as the primary emission control system, emissions from all phases
of the operation are captured to some degree. However, inefficient
capture can result from cross drafts and cause significant quantities of
emissions to escape.
The coreless induction furnace is a cup-shaped vessel that uses
electrical energy to induce eddy currents in the metallic charge to
produce molten iron. Since very clean or preheated scrap must be charged
to the induction furnace, emissions are generally less than the cupola or
the EAF. Hence, these furnaces are often uncontrolled. In that case, the
total furnace operation becomes a fugitive emission problem.
Two of the most significant sources of fugitive emissions in the iron
foundry are the pouring of hot metal into sand molds and subsequent
cooling of the castings. These processes vary significantly in different
60
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foundries. In nonmechanized foundries, the molds are generally placed in
a large open area. The hot metal ladle is then moved by an overhead
pulley system to the mold, and the casting is poured and cooled in
place. In more mechanized foundries, the mold is placed on a conveyor,
moved to the pouring station, and then moved to a cooling area. Emission
problems are comparable for both processes. The emissions are contained
in a relatively high-temperature, buoyant, moist stream. The constituents
of the stream are fine metal lies from the hot metal and organics produced
by thermal decomposition of the binders. The damp buoyant stream and the
organic emissions make controlling these sources difficult.
The only major sources of fugitive emissions in the finishing area
are casting shakeout and grinding. Shakeout is the method by which the
iron casting is removed from the sand mold. Shakeout varies more from
plant to plant than any other foundry operation. Observations during a
limited number of foundry visits revealed shakeout being accomplished
manually by forklift or hand shovel, mechanically on a grate shakeout, and
pneumatically by elevating the flask and shaking the sand and casting
out. In any case, the emissions consist of dust from the dried sand,
organic residue from binders, and water vapor. Lead emission problems are
likely to be minimal.
Grinding may also be a source of fugitive emissions in an iron
foundry. Four basic types of grinders are used in foundries: bench,
floor stand, portable, and swing. Each of these is a source of
particulate emissions. Little information was obtained on the particle
size or total amount of emissions from grinding. However, some plant
operators indicated that the finishing room was a significant industrial
hygiene problem.
3.4.3 Fugitive Emission Rates
Data on fugitive lead emissions from iron foundry operations are
quite limited. These limited data, which are presented in Table 15, are
based on information presented in AP-42.
61
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TABLE 15. FUGITIVE EMISSIONS FACTORS FOR IRON FOUNDRIES
Source
Emission
factors, kq/Mq
PM Lead
Comment
Cupola
Electric arc
furnace
Scrap handling
Pouring, cooling
Shakeoutb
0.69 0.0005-0.06
0.63 0.005-0.054
0.3
2.1
1.6
Based on 10 percent of
uncontrolled stack
emissions
Based on same lead to PM
ratio as cupola
*A11 emission factors are in kg/Mg of metal produced.
DReference 62.
62
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4.0 PROCEDURES FOR ESTIMATING FUGITIVE EMISSIONS
This section outlines procedures for estimating fugitive emissions
from the targeted industries. .Procedures are presented in a step-by-step
format. First, methods for estimating primary lead smelting fugitive lead
emissions are presented, followed by those for secondary lead. Estimation
procedures for the other industries of concern will then be addressed. As
mentioned in Section 3.3, lead-acid battery manufacturing fugitives are,
in general, negligible and therefore will not be addressed here.
4.1 PRIMARY LEAD SMELTING
4.1.1 Open Dust Fugitive Emissions Estimation
As discussed in Section 3.1, the major sources of open dust fugitive
emissions at primary lead smelters are paved and unpaved roads. Lead
concentrate handling operations may also contribute to fugitive lead
emissions but are likely to be insignificant in comparison to traffic
emissions. Open dust fugitive emissions can be estimated using
Equations 1, 2, 3, and 4, presented in Section 2.0 for paved roads,
unpave.d roads, materials handling, and wind erosion, respectively.
To estimate traffic emissions, surface dust loading and silt content
must be determined. Because of variations in these parameters from plant
to plant and within plants, site-specific data should be obtained whenever
possible. Appendix A describes procedures that can be used for sampling
road dust to obtain representative values. Procedures for laboratory
analysis of dust samples are provided in Appendix B. When this
information is unavailable, the data provided in Table 6 can be
substituted as default values. However, estimates derived using these
data should be used for preliminary assessment only. As can be seen from
Table 6, surface dust loading ranged from 44.7 kg/km to 747 kg/km. In
general, roads used for hauling ore concentrate had surface loadings at
the higher end of the range, and roads used mainly for finished product
hauling fell in the lower end of this range. Silt content varied from
27.9 percent to 90.4 percent and averaged 60.0 percent for paved roads;
for unpaved roads, it varied from 5.11 percent to 12.2 percent and
averaged 8.37 percent. Road length, vehicle speed and weight, traffic
volume, and the number of lanes can be obtained from plant records at many
facilities. Table 6 includes data for these parameters for two primary
lead smelters.
63
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The only significant open dust source of fugitive lead emissions,
other than roads, is potentially the ore concentrate storage pile during
loading and unloading. Table 16 summarizes data for lead ore concentrate
and other storage piles at two primary lead smelters. Values recorded for
moisture and lead content are probably representative of the industry, but
site-specific data should be used whenever possible. Ore concentrate is
typically stored in enclosed or partially enclosed buildings, so, the
actual emissions are most likely somewhat less than would be predicted by
Equation 3 because much of the entrained particulates would settle in the
building without being emitted to the outside environment.
Step-by-step procedures for estimating open fugitive dust emissions
at primary lead smelters are provided in Appendix C.
4.1.2 Process Fugitive Emissions Estimation
Process fugitive emission sources for primary lead were discussed in
Section 3.1.2. As mentioned in that section, the major process sources of
fugitive lead emissions are sintering and furnace leakage and tapping.
Process fugitive emissions can be estimated by multiplying the appropriate
emission factor by the production rate. Table 17 summarizes the process
emission factors for a primary lead sintering operation, blast furnace,
reverberatory furnace, and dross kettle. These emission factors are taken
from Reference 13 (AP-42) and all have a rating of D. Because of this low
rating, these emission factors produce order of magnitude estimates only
and thus should be used with caution, particularly when they are used to
estimate fugitive lead emissions from a specific facility.
4.2 SECONDARY LEAD SMELTING
4.2.1 Open Dust Fugitive Emissions Estimation
As indicated in Section 3.2, the primary sources of open dust
fugitive emissions are vehicle traffic on plant surfaces and raw and
recycle material storage. The major vehicular traffic components are
large transport trucks that travel over plant roads to deliver raw
materials and pick up finished products and the front-end loaders and
fork!ifts that are used to transport materials throughout the plant.
Primary materials of concern relative to lead emissions are scrap lead
(particularly lead oxide pastes), dross, slag, and flue dust. The
procedures that can be used to estimate emissions from each of these major
open dust sources are described below.
64
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TABLE 16. MOISTURE, SILT, AND LEAD CONTENT OF STORAGE PILE MATERIALS
AT TWO PRIMARY LEAD SMELTERS4
Moisture
content,
percent
Silt
content,
percent by
weight
Lead
content,
percent
by weight
Plant A
Ore concentrate pile
Baghouse dust
3.7
6,9
66.3
28.1
76.99
61.38
Plant B
Ore concentrate pile
Sinter pile
6.1
0.15
46.9
0.56
78.55
59.97
References 63 and 64.
65
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TABLE 17. PROCESS FUGITIVE EMISSION FACTORS FOR PRIMARY LEAD SMELTING
Process
Sintering
Blast furnace
Reverberatory furnace
Dross kettle
Lead emission
factor, kg/Mg
0.10
0.12b
0.24C
0.18d
Emission
factor rating
D
D
D
D
^Reference 65, for entire sinter building.
Reference 66, includes charging, tapping, and leakage.
^Reference 67, includes charging, tapping, and leakage.
Reference 68.
66
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The equations that are used to estimate fugitive lead emissions from
vehicular traffic were presented in Section 2.0 (see Equations 1 and 2).
Input values for lead silt loading (a product of total dust loading in
units of kg/km, silt content of the dust, and lead content of the silt),
number of traffic lanes, vehicle weight, and traffic intensity (vehicle
kilometers or miles traveled) are needed to implement these equations.
All three parameters that affect lead silt loading are likely to vary
widely from plant to plant and at different locations within the same
plant. Factors that will affect these loading parameters are proximity to
the travel surface of unenclosed material storage operations, plant
material handling practices (both process type and precautions taken to
avoid spillage), and plant housekeeping practices. Because these
parameters do vary widely, emission inventories for individual secondary
lead smelters should be based on plant-specific road dust samples if at
all possible. Appendix A describes procedures for collecting dust
samples, and Appendix B includes analytical techniques used to determine
total loading, silt content, and moisture content. If plant-specific
samples cannot be obtained, estimates can be developed using the limited
data presented in Section 3.2.3. Data based on limited sampling suggest
that dust loadings range from 10 to 50 g/m2, silt contents range from 15
to 33 percent, and lead contents of the dust range from 25 to
50 percent. The wide ranges in these data suggest that they should be
used with caution and only to develop preliminary bounds on emission
levels.
Plant traffic intensity can be estimated through two different
procedures. The first, which is recommended for truck delivery traffic
and can also be used for internal plant transport, is: (1) to map the
pathway followed by a vehicle in completing a given activity, and
(2) obtain an estimate from plant personnel on the number of such trips
made during a specified time period. As an example, consider scrap
battery delivery operations. Typically, these battery delivery vehicles
will follow a specified pathway along plant roads from the gate, to the
receiving area, and back to the gate. Plot this pathway on a plant map
and determine the total length. The average number of vehicle miles
traveled per day by battery delivery trucks is simply the product of the
67
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length of the path and the average number of deliveries daily. (If the
vehicles make a round trip, the number of deliveries is doubled). This
last figure can be obtained readily from plant records. Application of
this method to internal transfers requires detailed information on
transfer pathway and numbers of transfers. This information typically is
more difficult to obtain than shipping and receiving information. As an
alternative, estimates of internal transfer traffic intensity can be
developed from plant information on the number of transfer vehicles
operated per shift and average distance that a transfer vehicle travels
during a shift. This latter parameter can frequently be obtained from
maintenance records. Other parameters (i.e., number of lanes and vehicle
weight) can also be obtained from plant records.
One mitigating factor needs to be considered in estimating internal
transfer vehicular emissions. Many secondary lead smelters have partially
enclosed the complete smelting/casting operations, and some storage areas
are contained in these partial enclosures. In such facilities some
transfer traffic occurs in "yard" areas within the enclosure. While this
traffic is likely to result in the same amount of particle suspension as
outdoor traffic, the protection of the enclosure increases the likelihood
that these suspended particles will settle before reaching plant
boundaries. No data are available on the degree of "emission reduction"
associated with such "enclosed traffic." However, some reduction
(possibly as much as 50 percent) should be considered for such situations.
The equations for estimating emissions associated with storage
operations for scrap lead, slag, dross, and flue dust are presented in
Section 2.0 (see Equation 3). These emissions may occur from handling
operations as materials are loaded onto or off of piles or from wind
erosion of piles. Note that in many facilities materials are stored in
containers or three-sided enclosures to minimize these emissions.
The primary material characteristics that are needed to estimate
emissions from storage operations are moisture content of the material,
silt content, and lead content. It is highly recommended that inventories
be based on plant specific sampling and analysis of these materials.
Procedures for such sampling and analyses are described in Appendices A
and B. No data were found in the literature on either the moisture
68
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content or the silt content of these materials. The limited data that
were obtained on lead content are presented in Tables 11 and 12.
Step-by-step procedures for estimating open fugitive dust emissions
from secondary lead smelters are provided in Appendix C.
4.2.2 Process Fugitive Emissions Estimation
The sources of process fugitive emissions from secondary lead
smelters are listed in Table 10. The major sources were charging and
tapping operations at the smelting furnace and all kettle furnace
operations (since these furnaces may be uncontrolled). Minor sources
include the battery wrecking unit and casting. Generally, emissions from
these operations are estimated by multiplying a production rate by an
appropriate emission factor. The limited information that was obtained on
emission factors for these sources is presented in Table 18.
69
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TABLE 18. EMISSION FACTORS FOR PROCESS FUGITIVE EMISSION SOURCES IN SECONDARY LEAD SMELTERS
Source
Emission factor
Comment
Blast furnace
-- Total*
— Charging
— Slag tapping
— Lead tapping
Reverberatory furnace
~ Total
Refining kettle
Casting
1.6-3.5 kg/Mg lead producedb
1.2 kg/Mg feedc
0.13 kg/Mg feedc
0.0047 kg/Mg feedc
0.85-2.4 kg/Mg lead produced1
0.006 kg/Mg lead producedb
0.00055 kg/Mg lead charged0
0.0007 kg/Mg lead produced0
Flue dust agglomeration 14 Kg/Mg flue dust charged*
Based on 5 percent
emissions
Based on emission
baghouse on well
Based on emission
baghouse on well
Based on emission
baghouse on well
of uncontrolled stack
test upstream from
-controlled system
test upstream from
-controlled system
test upstream from
-controlled system
Based on 5 percent of uncontrolled stack
emissions
Based on 100 percent of uncontrolled
emissions
Based on stack test upstream from baghouse
of well-controlled facility
Based on stack test upstream from baghouse
of well-controlled facility
Based on stack test upstream from baghouse
of well-controlled facility
^Charging, slag tapping, lead tapping.
"Reference 69.
Reference 70.
-------
5.0 CONTROL OF FUGITIVE EMISSIONS
This section describes measures used to control fugitive emissions at
primary and secondary lead smelters. First, general open dust fugitive
emission controls are described. A general description of process
fugitive emission control measures is then presented. Finally, industry-
specific fugitive emission control measures are described for primary and
secondary lead smelting.
5.1 OPEN DUST FUGITIVE EMISSIONS CONTROLS
Control measures for open fugitive dust emission sources fall into
three general categories: preventive measures, measures to remove surface
dust, and dust suppressant measures. This subsection describes how these
fugitive control measures are applied to paved roads, unpaved roads, and
storage piles. Most of the material presented in this section is adopted
from Reference 3.
5.1.1 Paved Road Control Measures
Because of the importance of surface loading, most available control
techniques for fugitive dust emissions from paved roads attempt either to
prevent material from being deposited on the surface or to remove
deposited material from the travel lanes. This section describes four
paved road control techniques: preventive measures, broom sweeping,
vacuum sweeping, and water flushing.
5.1.1.1 Preventive Measures. As the name implies, preventive
control measures prevent the deposit of additional materials on a paved
surface area. Table 19 lists some of the more commonly used preventive
control measures for paved road fugitive emissions. Preventive measures
can have a significant impact on open dust fugitive emissions. For
example, mud and dirt carryout from unpaved areas such as parking lots and
storage piles often accounts for a substantial fraction of paved road silt
loadings in many areas. The elimination of this carryout can
significantly reduce paved road emissions.
Other preventive controls for certain sources of paved road silt
loadings include measures designed to prevent losses of materials
transported in trucks, vegetative covers, and wind breaks. Data are
scarce on emissions reductions that result from these preventive
measures. Thus, it is difficult to estimate their control
effectiveness.
71
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TABLE 19. NONINDUSTRIAL PAVED ROAD DUST SOURCES AND PREVENTIVE CONTROLS*
Source of deposit on road
Recommended controls
— Spills from haul trucks
— Require trucks to be covered
~ Require freeboard between load and
top of hopper
--Wet material being hauled
Construction carryout and
entrainment
Clean vehicles before entering road
Pave access road near site exit
See discussion on construction
Semicontinuous cleanup of exit
Vehicle entrainment from
unpaved adjacent areas
Pave/stabilize portion of unpaved
areas nearest to paved road
Entrainment from stormwater
washing eroded soils
onto streets
Wind erosion from adjacent
areas
Improve storm water control
Vegetative stabilization
Rapid cleanup after event
Wind breaks
Vegetative stabilization or
chemical sealing of ground
Pave/treat parking areas, drive-
ways, shoulders
Limit traffic or other use that
disturbs soil surface
Reference 71.
72
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5.1.1.2 Broom Sweeping of Roads. Mechanical street cleaners employ
rotary brooms to remove surface materials from roads and parking lots.
However, a substantial fraction of the original loading is emitted during
the process, and thus broom sweeping may not be very effective as a
control of fugitive particulate emissions.
Measurement-based control efficiency for industrial roads (Table 20)
indicates a maximum (initial) instantaneous control of roughly 25 to
30 percent.
5.1.1.3 Vacuum Sweeping of Roads. Vacuum sweepers remove material
from paved surfaces by entraining particles in a moving air stream. A
hopper is used to contain collected material and air exhausts through a
filter system. A regenerative sweeper functions in much the same way,
although the air is continuously recycled. In addition to the vacuum
pickup heads, a sweeper may also be equipped with gutter and other brooms
to enhance collection.
Instantaneous control efficiency values are provided in Table 20.
Available data are inconsistent but indicate efficiencies up to
58 percent. An average of the available data indicates an efficiency of
34 percent.
5.1.1.4 Water Flushing of Roads. Street flushers remove surface
materials from roads and parking lots using high-pressure water sprays.
Some systems supplement the cleaning with broom sweeping after flushing.
Unlike the two sweeping methods, flushing faces some obvious drawbacks in
terms of water demand and the frequent need to return to the water source.
However, flushing generally tends to be more effective in controlling
particulate emissions.
Equations to estimate instantaneous control efficiency values are
given in Table 20. Note that water flushing and flushing followed by
broom sweeping represent the two most effective control methods described
here.
5.1.2 Unpaved Road Control Measures
There are numerous options for controlling fugitive emissions from
unpaved travel surfaces, as shown in Table 21. These controls fall into
the three general categories of source extent reductions, surface
improvements, and surface treatments. Source extent reductions either
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TABLE 20. MEASURED EFFICIENCY VALUES FOR PAVED ROAD CONTROLS
Method
Cited
efficiency
Comments
Vacuum sweeping 0-58 percent
Water flushing
Water flushing
followed by
sweeping
46 percent
69-0.231 Vc'd
96-0.263 Vc'd
Field emission measurement (PM-15),
12,000-ft3/min blower5
Reference 7, based on field measurement
of 30 urn particulate emissions
Field measurement of PM-15 emissions5
Field measurement of PM-15 emissions5
Reference 72. All results based on measurements of air emissions from
industrial paved roads.
bPM10 control efficiency can be assumed to be the same as that tested.
^Water applied at 0.48 gal/yd2.
"Equation yields efficiency in percent, V = number of vehicle passes since
application.
74
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TABLE 21. CONTROL TECHNIQUES FOR UNPAVED TRAVEL SURFACES
Type of control
Specific control
measures
Source extent reduction:
Source improvement:
Surface treatment:
Speed reduction
Traffic reduction
Paving
Gravel surface
Watering
Chemical stabilization
— Asphalt emulsions
— Petroleum resins
~ Acrylic cements
— Other
Reference 73.
75
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limit the amount of traffic on a road to reduce the fugitive dust emission
rate or lower speeds to reduce the emission factor value given by
Equation 2. Surface (aggregate) improvements permanently alter the road
surface and include paving and covering the road surface with a material
of lower silt content. Surface treatment refers to those control tech-
niques that require periodic reapplications and can be categorized as
(1) wet suppression, which keeps the surface wet to control emissions, and
(2) chemical stabilization, which changes the physical characteristics of
the roadway. Each of these control measures is described in greater
detail below. It is important to note that for the purpose of estimating
annual or seasonal controlled emissions from unpaved roads, average
control efficiency values based on worst case (i.e., dry, p = 0 in
Equation [2]) uncontrolled emission levels are required.
5.1.2.1 Source Extent Reductions. These control methods act to
reduce the emission rate due to traffic on a road. The reduction may be
obtained by banning certain vehicles or strictly enforcing speed limits.
Control efficiency values are easily obtained using Equation 2. For
example, because emissions are proportional to vehicle speed, reducing
vehicle speed by 25 percent results in a corresponding 25 percent
reduction in fugitive emissions.
5.1.2.2 Surface Improvements. These control measures consist of
either paving or replacing aggregate with one of lower silt content.
Paving is most applicable to high-volume roads that are not subject to
very heavy vehicles such as haul trucks. Control efficiency estimates for
paving previously unpaved roads may be based on the material presented in
Section 5.1.1 on paved road control techniques. Aggregate improvement
reduces total suspended part.iculate emissions by reducing the silt content
of the road surface. However, this type of control has little effect on
fugitive lead emissions because lead particles are deposited on the road
by other sources.
5.1.2.3 Watering. Watering is a temporary measure, and periodic
reapplications are necessary to achieve any substantial level of control
efficiency. The control efficiency of unpaved road watering depends upon
(a) the amount of water applied per unit area of road surface, (b) the
time between reapplications, (c) traffic volume during that period, and
76
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(d) prevailing meteorological conditions during the period. Wetting
agents, such as surfactants that reduce surface tension, may be added to
increase the control efficiency of watering.
An empirical model for the performance of watering as a control
technique is as follows:
C = 100 - °'8 ? d t (5)
where:
C = average control efficiency, percent;
p = potential average hourly daytime evaporation rate, mm/hr;
d = average hourly daytime traffic rate, number of vehicles per hour
(1/hr);
i = application intensity, liters per square meter (L/m ); and
t = time between applications, hr.
Estimates of the potential average hourly daytime evaporation rate may be
obtained from
0.0049 x (value in Figure 1) for annual conditions, or
p ~ 0.0065 x (value in Figure 1) for summer conditions
5.1.2.4 Chemical Treatments. Chemical treatments for unpaved roads
fall into two general categories: (1) chemicals that simulate wet
suppression by attracting and retaining moisture on the road surface, and
(2) chemical dust suppressants that form a hard cemented surface.
Treatments of the first type, typically salts, are usually supplemented by
watering. Included in the second category are petroleum resins, asphalt
emulsions, acrylics, and adhesives. These are the treatments most
commonly used.
The control efficiency of chemical dust suppressants is a function of
the frequency of application and the ground inventory. The ground
inventory is the cumulative volume of chemical concentrate (not solution)
applied to the road. Control efficiency for chemical dust suppressant use
can be estimated using Figure 10. For example, if 0.25 L/m2 of chemical
concentrate is applied at 1 month intervals, after 3 months the ground
77
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CHEMICAL DUST SUPPRESSANT
CONTROL EFFICIENCY MODEL
0.05 0.1 0.15 0.2
Ground Inventory (gal/sq yd)
0.25
Figure 10. Chemical dust suppressant control efficiency model
71*
78
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inventory 1s 0.75 L/m2. This corresponds (in Figure 10) to approximately
80 percent control efficiency.
Repeated use of chemical dust suppressants tends to form fairly
impervious surfaces on unpaved roads. The resulting surface may admit the
use of paved road cleaning techniques (such as flushing, sweeping, etc.)
to reduce surface loading due to spillage and track-on. Generally, using
these methods is not recommended until the ground inventory exceeds
approximately 0.9 L/m2 (0.2 gal/yd2). It is recommended that at least
minimal reapplications be employed every month to control loose surface
material unless paved road control techniques are used (as described
above). More frequent reapplications would be required if spillage and
track-on pose particular problems for a road.
It should be noted that roads generally have higher moisture contents
during cooler periods due to decreased evaporation. Small increases in
surface moisture may result in large increases in control efficiency.
5.1.3 Storage Pile Control Measures
The control techniques that apply to storage piles fall into distinct
categories as related to materials handling operations (including traffic
around piles) and wind erosion. In both cases, control can be achieved
by: (1) source extent reduction, (2) source improvement related to work
practices and transfer equipment (load-in and load-out operations), and
(3) surface treatment. These control options are summarized in
Table 22. The efficiency of these controls ties back to the emission
factor relationships presented earlier in Section 2.1.3.
Source extent reduction measures, such as reducing the area of
materials disturbed, reducing the frequency of disturbances, and promptly
cleaning up spills, are largely a function of work practices. This type
of control measure can be applied without the need to invest in a control
program. Many of the source improvement measures listed in Table 22 can
also be applied through good work practices, and these will not be
discussed further here. The remaining control measures, i.e., storage
pile enclosures, chemical stabilization, and wet suppression, are
described in more detail below.
5.1.3.1 Enclosures. Enclosures are an effective means by which to
control fugitive particulate emissions from open dust sources. Enclosures
79
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TABLE 22. CONTROL TECHNIQUES FOR STORAGE PILES
Type of control
Specific control measures
Material handling
Source extent reduction
Source improvement
Surface treatment
Wind erosion
Source extent reduction
Source improvement
Surface treatment
Mass transfer reduction
Drop height reduction
Wind sheltering
Moisture retention
Wet suppression
Disturbed area reduction
Disturbance frequency reduction
Spillage cleanup
Spillage reduction
Disturbed area exposure (wind)
reduction
Wet suppression
Chemical stabilization
Reference 75.
80
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can either fully or partially enclose the source. Enclosures
traditionally used for open dust control include three-sided bunkers for
storing bulk materials, storage silos for various types of aggregate
materials, open-ended buildings, and similar structures. Practically any
means that reduces wind entrainment of particles produced either by
erosion of a dust-producing surface (e.g., storage silos) or by dispersion
of a dust plume generated directly by a source (e.g., front-end loader in
a three-sided enclosure) is generally effective in controlling fugitive
particulate emissions. However, available data are not sufficient to
quantify emission reductions.
Partial enclosures used to reduce windblown dust from large exposed
areas and storage piles include porous wind fences and similar types of
physical barriers (e.g., trees). Again, there are insufficient data
available to generalize about the effectiveness of these types of
enclosures.
A storage pile may itself serve as a wind break by reducing wind
speed on the leeward face. The degree of wind sheltering and associated
wind erosion emission reduction depends on the shape of the pile and on
the approach angle of the wind to an elongated pile.
5.1.3.2 Chemical Stabilization. Petroleum resins and latex builders
are two of the more commonly used chemical stabilizers on storage piles.
The quantities used are typically small enough to have negligible effects
on the use of the storage pile material itself. Very few data are
available for control efficiencies of chemical stabilizers. Tests using a
petroleum resin of an undisturbed steam coal pile (applied 60 days prior
to testing) indicated a total particulate control of 89.6 percent.
5.1.3.3 Wet Suppression Systems. Fugitive emissions from materials
handling systems are frequently controlled by wet suppression systems.
These systems use liquid sprays or foam to suppress the formation of
airborne dust. The primary control mechanisms are those that prevent
emissions through agglomerate formation by combining small dust particles
with larger aggregate or with liquid droplets.
Liquid-spray wet suppression systems can be used to control dust
emissions from materials handling at conveyor transfer points. The
wetting agent can be water or a combination of water and a chemical
81
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surfactant. This surfactant, or surface active agent, reduces the surface
tension of the water. As a result, the quantity of liquid needed to
achieve good control is reduced. For systems using water only, adding
surfactant can reduce the quantity of water necessary to achieve a good
control by a ratio of 4:1 or more.
Micron-sized foam application is an alternative to water spray
systems. The primary advantage of foam systems is that they provide
equivalent control at lower moisture addition rates than spray systems.
However, the foam system is more costly and requires extra materials and
equipment. The foam system also achieves control primarily through the
wetting and agglomeration of fine particles.
5.2 PROCESS FUGITIVE EMISSIONS CONTROLS
The most widely used methods of controlling process fugitives are
local ventilation and building enclosure/evacuation. Both types of
systems have their advantages and drawbacks, but local ventilation is
generally more cost effective. Process optimization, good operation and
maintenance, and other industry-specific practices can also be quite
effective in reducing process fugitive emissions.
5.2.1 Local Ventilation Systems
Local ventilation systems may consist of a secondary hood at the
local source of emissions or large canopy-type hoods suspended over the
source. One specific variation of a secondary local hood is the mobile
hood which can be used to collect emissions from pots or other containers
that must be set aside for cooling. Each ventilation system must be
uniquely designed to conform with facility configuration and the need for
process access. However, the systems are all designed to meet several
common objectives. First, the hood should enclose the source to the
degree possible without interfering excessively with process access needed
for normal operations. Second, the hood should be configured in such a
way that natural buoyancy or mechanical forces direct the plume into
rather than away from the hood. Finally, the system must be designed with
sufficient exhaust ventilation to maintain recommended face velocities at
all hood faces. Typically, these velocities are in the range of 75 to
150 m/min. Additionally, note that for buoyant plumes that generate a
natural draft, the ventilation rate must exceed the plume generation rate
or "spillage" from the hood will occur.
82
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Ventilation hooding and ductwork may be difficult to retrofit in some
facilities due to space limitations. In addition, local ventilation
systems may limit personnel and equipment access. For these reasons, a
local ventilation system may not be a feasible method of process fugitive
emissions control for specific operations at some facilities. The
paragraphs below describe local ventilation systems that have been
demonstrated to work well on metallurgical operation emission sources.
One of the major sources of process fugitive emissions in both
primary and secondary lead smelters is the blast furnace operation. Blast
furnace fugitive emissions are generated from the charging area near the
top of the furnace and from the slag and metal tapping operations,
launders, and mold-filling areas at the base of the furnace. Figures 11
through 13 illustrate components of a system on a secondary lead smelter
blast furnace after it was modified to provide an acceptable level of
control. Note in particular the slot hood in Figure 11 that was designed
to collect emissions leaking from access doors at the top of the blast
furnace. Because this hood is collecting gas perpendicular to the buoyant
flow, high face velocities are required. In contrast, the launder hood is
positioned so that the buoyant plume is directed into the hood. Details
of the lead-tapping hoods on a comparable system are shown in Figure 14.
Figure 15 presents a more enclosed version of a lead-tapping hood system.
Although each design will be unique, local controls comparable to
those described above can be used on most stationary type furnaces.
Within the group of industries examined here, such furnaces include blast
furnaces, reverberatory furnaces, and cupolas. A very different control
problem is presented by nonstationary furnaces that rotate during
operation or during charging and tapping. Examples include electric arc
furnaces and rotary furnaces. One key feature of these systems is that
charging and tapping occur in the same general area. Hence, the hooding
system for both systems must be designed in such a way that it interferes
with neither operation.
Figure 16 shows a successful rotary furnace ventilation system that
has been used in a secondary lead smelter. Hot flue gases are exhausted
through the brick flue. The gap between the furnace body and the brick
flue is enclosed and exhaust ventilated. An arched hood is provided over
83
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• T1S
SLOT HOOD OVER ACCESS
DOORS TO FURNACE
TiJ
— TO
8ACHOUSE
(T9 & TiO)
EXHAUST PICKUPS
FOR SKIP HOIST
LOADING HOOO
SKIP HOIST FURNACE
CHARGING HOOD
MOLD
FILLING
HOOD
EXHAUST PICKUPS FOR
NEW KETTLE HOODS
Figure 11. Overview of modifieo^ local exhaust
ventilation system.
84
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TOTn
SIAQ TAPPING
HOOD
FRONT
SURFACE OF
HOOD RAISED
USING CABLE &
PULLEY SYSTEM
METAL DUCT
'DIAMETER = Menu-is*)
SLAG
CONTAINER
Figure 12. Blast furnace slag tapping hood.
77
85
-------
NEW RAW
MATERIALS
CONFINEMENT
VOID IN
ENCLOSURE
TO TOP OF
BLAST FURNACE
SKIP HOIST
ENCLOSURE
EXHAUST DUCTS
STEEL PLATE
BARRIER
FLUE DUST
AGGLOMERATED
FLUE DUST
•SLAG
LIMESTONE CHIPS
Figure 13. Skip hoist ground level loading station.
78
86
-------
Blase gact
F«c«
*c back of hood
vf • 0.75 - 1.8 •/•
(130 - 350 fpa)
Coolln;
'vmccr r«««rvoi:
BLAST TOWAGE BLOCK CASTING HOOD
llMI Ml*
1100 . tOO !mt
BUST PUIIUCE LAUNDER HOOD
Figure 14. Alternate suggested design concept (gr blast furnace
launder and block casting hoods.
87
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co
CO
BA6HOU6E
BUTTtRFLt CfcHPEK
HINGED LAUNDER
POOP-
ROUJMG PROMT TOP
FURNACE
CRUCIBLE
DESIGN CHARACTERISTICS
ENCLOSURE TO PROVIDE
CAPTURE VELOCITIES AT OPENING
OF 350 - 50O FPU
TRANSPORT VELOCITY
IN OUCTSs
^ 4OOO FPU
SlDt
METAL. AjVFSS
TO Pi^V/ID£ FUU.
TO PW3iJr OF
EXAMPLES OF FEASIOLE ENCLOSURE IIOODIUO -QLAST
ENGINEERING CONTROLS FURNACE LEAH TAP CONTROLS
Figure 15. Suggested design concept for blast furnace lead tapping hood system (lead tap,
launder, and block casting).80
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Electrically
Operated
Damper
Retractable arch
hood enclosures
Finished
aetal ladl
Brick flue
Hood enclosing
furnace to flue
connection
Wide sloe exhaust
pickups
168 on (5 ft 5 in)
Figure 16. Rotary furnace charging and tapping controls.
81
89
-------
the charging/tapping end of the furnace. Exhaust draft to this hood 1s
controlled by an electrically operated damper. The damper 1s opened
during charging and tapping. This facility has two furnaces that are
operated on staggered 10-hour cycles. Hence, the exhaust draft can be
directed from one furnace to the other during alternating charging and
tapping operations. The retractable portions of the arched hood open to
allow an overhead crane to pick up filled ladles and replace empty ladles.
One problem common to all types of metallurgical furnaces is the
emission of fumes from metal ladels or slag pots during cooling.
Typically, these containers are left at the hood for a short time and then
moved to a holding area to allow them to cool further. Because the metal
is still very hot, lead fumes and other relatively volatile metals such as
arsenic frequently are emitted during cooling. These emissions can be
controlled by a mobile hood such as the one shown in Figure 17. Note the
chains around the base of the hood that are used to provide a barrier
without threatening the structural integrity of the hood."
5.2.2 Building Enclosure/Evacuation
Enclosing and ventilating an entire building may be the only feasible
control method when the process operation is characterized by a number of
small fugitive emissions sources. A typical building evacuation system
might consist of opposing wall-mounted ventilators that force air across
process equipment and out through an overhead plenum to a fabric
filter.83 In order to limit worker exposure to emissions and expel the
heat generated by process operations, large airflow rates are required.
Operation costs for this type of system can thus be prohibitive. In
addition, the need to keep the building enclosed for such a system may be
too restrictive on the movement of fork!ifts and other equipment into and
out of the building.
5.2.3 Other Process Fugitive Controls
Good operation and maintenance practices can help to reduce process
fugitive emissions significantly. Prompt repairs of exhaust hood leaks
and maintenance of door seals are are two examples of O&M practices that
can help to minimize fugitive emissions.
Process optimization can be an effective preventive measure for
process fugitive emission control. These measures must be investigated on
90
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Duct flna for
structural
support of hood
Swivel bearing
Inside diameter
19.7 cm (7.75 In)
Finished
metal ladle
Hood Entry Coefficient
Ce - 0.58 N
Air flow measurements
V, (at chains) - 0.51-1.9 npa
taCe (100-250 fpm)
V - 5.1-10 iups (1000-2000 fpm)
B 10 C
Hood radius
80 cm (31.5 In)
Radius to slot
64.8 cm (25.5 In)
Side elevation of finished
metal ladle cooling hood
Detail of slot design Inside hood
Figure 17. Finished metal ladle cooling hood.f
-------
a case-by-case basis, however. An example of process optimization at a
primary lead smelter is designing the sulfuric acid plant with sufficient
capacity to preclude the creation of back pressure and excess venting of
the sinter machine.
5.3 INDUSTRY-SPECIFIC CONTROLS
This section describes the measures used at primary and secondary
lead smelters to control fugitive emissions. Primary lead smelting
controls are presented first, followed by secondary lead smelting fugitive
emission controls.
5.3.1 Primary Lead Smelter Fugitive Emission Controls
The following paragraphs describe the measures used to control
fugitive emissions at primary lead smelters. Open dust fugitive emission
controls are first presented. Process fugitive emission controls are then
discussed.
5.3.1.1 Open Fugitive Dust Emission Controls.8*1'85 Watering is the
most commonly used measure for controlling paved road fugitive emissions
at primary lead smelters. Although this practice may reduce the potential
for dust reentrainment within plant premises, it allows the accumulation
of moist lead-bearing dust on truck undercarriages. As this dust dries,
it can easily be reentrained inside or outside plant premises. As
described in Section 5.1.1.4, water flushing, using high-pressure water
sprays, is a more effective use of water for controlling paved road
fugitive emissions.
At least one primary smelter uses a broom sweeper for paved road dust
control. This method also has serious drawbacks in that broom sweepers
may actually contribute to significant dust reentrainment.
Chemical dust suppressants are commonly used to control fugitive dust
emissions on unpaved roads at primary lead smelters. Use of both a
petroleum-based dust suppressant and a latex binder (soil cement) have
been reported.
Measures for controlling storage pile fugitive emissions due to
materials handling and wind erosion include watering and enclosing. Lead
ore concentrate is typically stored in bins inside semi-enclosed
buildings. This significantly reduces the potential for reentrainment of
lead-bearing dust. In addition, building floors are routinely wetted down
92
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to limit dust reentrainment. At one plant, trucks are unloaded in a
Q g
ventilated, enclosed area to minimize fugitive dust emissions.
5.3.1.2 . Process Fugitive Emission Controls. The primary lead
smelting industry uses several measures to control process fugitive
emissions. Many of these attempt to control the more significant process
fugitive emissions sources—sintering and furnace operation. Table 23
lists some of the process fugitive emission controls in use at primary
lead smelters. The most important of these are described below.
5.3.1.2.1 Sintering fugitive emission controls. Process fugitive
emissions from sintering operations are typically controlled with local
hooding and ventilation. Local ventilation of conveyor transfer points is
of particular importance because fugitive emissions are potentially
greater at these locations. Other measures for reducing fugitive
emissions from sinter conveyors include increasing ventilation, scraping
and washing down conveyor belts, and installing a belt turnover device,
which ensures that rollers contact only the clean side of the conveyor
belt.
Control measures used to reduce sinter machine process fugitives
include increasing ventilation and routinely replacing seals on the
machine hood.
If the sinter machine is ventilated to an acid plant process,
fugitives can also be minimized by ensuring that the acid plant is
operating properly. Failure of the acid plant to adequately ventilate the
sinter machine can result in excess back pressure on the sinter machine
and fume leakage. Sinter process fugitives collected are typically
directed to a baghouse or scrubber for particulate removal.
5.3.1.2.2 Blast/reverberatory furnace fugitive emission
an OA
controls. ' Fugitive emissions from blast and reverberatory furnaces
are most effectively controlled by means of fixed or movable hoods over
charging and tapping points. These systems are typically ventilated to a
fabric filter control device.
One plant reported a reduction in blast furnace slips by screening
out undersized coke (less than 1 inch). Another plant reported improved
blast furnace performance and reduced leakage by improving the furnace
water cooling system.
93
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TABLE 23. SPECIFIC PROCESS FUGITIVE LEAD EMISSION SOURCES AND
POTENTIAL CONTROLS AT PRIMARY LEAD SMELTERS3
Emissions source
Potential controls
1. Ore concentrate unloading
2. Feed end of sinter machine
3. Belt conveyors in sinter plant
4. Sinter machine leakage
5. Blast furnace leakage
6. Blast furnace tapping
7. Lead ladle pouring and change over
8. Kettle dressing
9. Refining
10. Miscellaneous
Wash down transport trucks
Sweep and/or wet down roads and ramps
Unload trucks in enclosed ventilated
buiIdings
Improve sea Is on hood
Increase hood ventilation
Reverse or twist belts
Wash down/scrape belts
Enclose and vent belts
Hood and ventilate all transfer points
Replace and maintain hood seals
Increase capacity of acid plant
Improve quality of concentrate
Improve coke quality to minimize
blows/upsets
Improve water cooling system to reduce
upsets
Fully cover and ventilate lead launder,
slag tap hole, slag launder, and slag
granulater
Hood and ventilate ladle during pour
Increase hood airflow
Totally cover ladle during change over
Use mobile hood on ladle during change
over"
Pump lead to dross kettles
Inject molten sodium to form liquid matte
rather than dross
Partially cover kettle
Continuous dressing
Cool lead pot to reduce fume generation
"Hide" dressing
Hood and vent kettle during.transfer, heat
and casting
Completely enclose and ventilate process
buiIdings
Wash down building interior at regular
intervals
"References 87 and 88.
Not in use at domestic primary lead smelters.
94
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Fugitive emissions from pouring lead from the ladle can be reduced by
a number of measures. The ladle can be hooded and ventilated during pour,
and a mobile hood can be used during changeover. Another proposed control
measure is to pump lead directly to the dross kettles using an electro-
magnetic pump.
One plant has reduced dressing fugitives by injecting liquid sodium
into the dressing kettle. The sodium reacts with the dross to form a
matte that can be handled as a liquid. Process fugitives generated in
transferring molten lead from the blast furnace to the dross reverberatory
furnace can also be reduced by means of a continuous dressing system. In
this system, the dross furnace is located adjacent to the blast furnace.
Molten lead flows continuously to the dressing unit. This process
eliminates fugitive emissions from transporting, pouring, and stirring the
molten lead.
5.3.1.2.3 Building enclosure/evacuation. Most of the process
operations at a typical primary lead smelter are located in a partially
enclosed building or series of buildings. This arrangement lends itself
to building enclosure and ventilation. However, in order to comply with
OSHA standards that limit worker exposure to heat and lead emissions, very
large airflow rates are required. Based upon one study, a minimum of
15 building volumes of air must be exchanged per hour to satisfy OSHA
requirements.
5.3.2 Secondary Lead Smelter Fugitive Emission Controls
This section describes the measures used at secondary lead smelters
to control fugitive emissions. First, open dust fugitive emission
controls are described. Process fugitive emission controls are then
presented.
5.3.2.1 Open Fugitive Dust Emission Controls.93 Watering and
enclosing are the most common methods of controlling open fugitive dust
emissions at secondary lead smelters. As discussed in Section 3.2, the
majority of roads and traffic areas in the secondary lead industry are
paved. Although road sweeping and vacuuming are practiced at some plants,
the majority of secondary smelters use watering for road dust control. In
1985, at least two plants were using atomatic sprinkler systems to control
road dust emissions. This method can be quite effective for limiting dust
95
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reentrainment within plant premises. The primary drawback of watering is
that (as discussed in Section 5.3.1.1) the dust can accumulate under
vehicles and, after drying, can be reentrained later. Some plants
minimize this problem by routinely washing down vehicle bodies.
Storage pile fugitive emissions are often controlled by wetting and
enclosing. Materials are often stored in drum containers, tote-boxes or
3-sided bins, in order to minimize wind erosion. According to one study,
11 of the 35 secondary lead plants operating in 1985 used total enclosure
of storage piles for fugitive dust control. (Nine of these smelters are
currently in operation.) In general, enclosed raw material storage piles
were vented to the atmosphere. Other storage pile materials, such as
9%
drosses and charge makeup were vented to fabric filters.
5.3.2.2 Process Fugitive Emission Controls.95 Because secondary
lead smelting operations occur in relatively confined areas and are labor
intensive, fugitive emission controls frequently have been installed with
a primary objective of reducing worker lead exposure. A secondary benefit
has been reducing lead emissions. In addition to improving general
housekeeping and implementing many of the fugitive dust control strategies
described in Section 5.1, the industry has employed two other major
control strategies to limit fugitive emissions. The first is to use
localized ventilation coupled with an air pollution control device
(typically a baghouse or, less commonly, a wet scrubber) to control
fugitive emissions from furnace operations. The second is to provide
mechanisms for reducing emissions from flue dust handling operations.
Each of these strategies is discussed briefly in the paragraphs below.
5.3.2.2.1 Local ventilation systems for furnace fugitives. As
indicated in Table 10, the primary sources of fugitive emissions from
secondary lead smelter furnace operations are the charging and tapping
operations at the smelting furnaces and the entire kettle refining
operations. Secondary lead smelters that have successfully controlled
emissions from these sources generally have used local ventilation exhaust
hoods coupled with a fabric filter. The furnace controls that have been
applied to the smelting furnaces and metal and slag ladles are comparable
to those described in Section 5.2.1.
96
-------
One final furnace control problem that may be present in secondary
lead smelters is that of the refining kettle. Unlike the smelting
furnace, the top of the kettle furnace is open. Hence, the primary
emissions from the kettle are not ducted to a control device and are
considered to be fugitive emissions. Consequently, the hooding system
must be designed to collect emissions from the furnace surface during
refining. At the same time, access for charging, tapping, and dressing
operations is necessary. Figures 18 and 19 present a suggested design
concept for refining kettles. The hooding system shown in Figure 18
collects emissions from charging, tapping, and refining operations. The
extension shown in Figure 19 collects emissions from dressing operations.
a o
5.3.2.2.2 Flue dust emissions control. One potentially major source
of fugitive lead emissions at secondary lead smelters is the handling of
flue dusts collected in the baghouses on the smelting furnaces and on the
scavenger systems. As of 1985, all 35 operating smelters had employed
some type of control system on their baghouse dust handling systems.
Eight smelters manually remove the dust from the baghouse hoppers and
store the material in enclosed boxes, bags, drums, or hoppers. Twenty-
four smelters remove flue dust from the baghouse hoppers automatically
with screw conveyors and either convey the dust to an agglomeration
furnace or a wet slurry tank or recycle the dust back to the smelting
furnace. The remaining three plants manually remove the flue dust and
store the material in partially enclosed bins or open storage piles.
These smelters attempt to control fugitive emissions by wet suppression,
by applying chemical suppressants and/or binders, and by covering the
piles with plastic.
The most effective means of control appears to be collecting the
material directly from the baghouse hopper and transportation directly to
an agglomeration furnace via a screw conveyor. This process is depicted
schematically in Figure 20.
The flue dust generated by smelting automobile battery and battery
manufacture scrap melts at approximately 400° to 900°C (750° to 1650°F).
This low melting point makes flash agglomeration of flue dust possible.
Dusts with higher melting points cannot be agglomerated using this
technique without causing the low-melting-point materials to volatilize.
97
-------
00
VOLUME Fl.OU RATE -
200 SCFM/SQ FT OF
KETTLE SURFACE AREA
DUCT VELOCITY x A000 FPH
FUME REMOVAL TMtfc-OFF IX1CTS
HOOD
HlMER
PtXTE.
MIXtK klOT IM
FOR
HIM6CD
CONSTIUCTION NOTES
- ENCLOSE TO PROVIDE AT
LEAST ISO FPH FACE VELOCITY
AT ALL OrENlKCS
- PROVIDE ADEQUATE LIFTING
POINTS F0» HOOD ASSEMBLY
ASSOCIATED DOCTUOUK
SLID4MG
RLFINIM6 KETTLt
PORT
DOORS
EXAMPLES OF FEASIBLE
ENGINEERING CONTROLS
ENCLOSURE MOOOINQ - REFINING
KETTLE EMISSION CONTROLS
Figure 18. Suggested design concept for refining kettle hoods.
-------
V/LMULATIOII
KCTTLE 4
HOOD
UD
EXHAUST
RJf HOOO
DESIGN CHARACTERISTICS
- ENCI.OSURE TO PROVIDE CAPTURE VELOCITIES
AT OPENINGS OF 350 - 500 FPN
- TRANSPORT VELOCITIES IN DUCTS:
k 4000 FPH
EXAMPLES OF FEASIBLE
ENGINEERING CONTROLS
ENCLOSURE HOODINO
DROSS, par noon
Figure 19. Suggested design concept for dross pot hoods.97
-------
BUANEA
•C OOUNG /TRA NSPQtTA TION
Figure 20. Flash agglomeration furnace.
99
100
-------
A special furnace was designed to take advantage of this property so that
dust handling could be completely avoided.
At most secondary lead smelters, it is common practice to return flue
dust directly to either the blast furnace or a reverberatory furnace. A
considerable amount of this dust is entrained in the furnace flue gas
system. Agglomerating the flue dust prevents entrainment, thus reducing
the load on the baghouse and improving its performance.
The agglomeration furnace is fed directly from the baghouse dust
hoppers via a screw conveyor. The dust drops onto the furnace hearth,
where it melts almost instantaneously upon contact with an impinging
flame. The liquid runs down the sloping hearth, through a permanently
open taphole, and into a cast-iron vessel, where it solidifies. This
process completely eliminates handling of the dust, the associated
occupational hazard, and fugitive emissions from flue dust storage piles,
provided that the agglomerated dust is stored indoors. Indoor storage is
important in preventing degradation of the aggregate.
Tipping the contents of the cast iron vessels onto the floor is
usually sufficient to break the material into lumps suitable for
recharging to the blast furnace. It is simply mixed with coke and flux
and loaded into the top of the blast furnace along with other charge
materials.
101
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6.0 REFERENCES
1. Strait, R., and W. Battye (Alliance Technologies Corporation). Cost
Assessment of Regulatory Alternatives for Lead National Ambient Air
Quality Standards. (Draft Final Report). Prepared for U. S.
Environmental Protection Agency, Research Triangle Park, North
Carolina, Contract No. 68-D8-0097, Work Assignment No. 2.
April 1989. p. 2-10.
2. Control Techniques for Lead Air Emissions from Stationary Sources--
Volume 2. (Preliminary Draft). U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina. March 1985.
p. 4.2-1, 4.3-1, 4.4-14, 4.5-1.
3. Cowherd, C., G. E. Muleski, and J. S. Kinsey (Midwest Research
Institute). Control of Open Fugitive Dust Sources. U. S.
Environmental Protection Agency, Research Triangle Park, North
Carolina. Publication No. EPA-450/3-88-008. September 1988. 219 p.
4. Reference 3, p. 2-13.
5. Supplement B to Compilation of Air Pollutant Emission Factors,
Volume I: Stationary Point and Area Sources. U. S. Environmental
Protection Agency, Research Triangle Park, North Carolina.
Publication No. AP-42. September 1988. p. 11.2.6-3.
6. Reference 5, p. 11.2.6-1.
7. Reference 3, p. 3-3.
8. Reference 3, p. 3-5.
9. Reference 5, p. 11.2.3-4.
10. Reference 2, p. 4.4-17.
11. Reference 2, p. 4.4-19.
12. Wallace, D., and C. Cowherd (Midwest Research Institute). Fugitive
Emissions from Iron Foundries. U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina. Publication
No. EPA-600/7-79-195. August 1979. p. 24.
13. Supplement A to Compilation of Air Pollutant Emission Factors,
Volume I: Stationary Point and Area Sources. U. S. Environmental
Protection Agency, Research Triangle Park, North Carolina.
Publication No. AP-42. October 1986. p. 7.6-1.
14. Reference 13, p. 7.6-2.
15. Reference 2, p. 4.3-9.
102
-------
16. Background Information for New Source Performance Standards: Primary
Copper, Z1nc, and Lead Smelters. Volume I: Proposed Standards.
U. S. Environmental Protection Agency; Research Triangle Park, North
Carolina. Publication No. EPA-450/2-74-002a. October 1974.
p. 3-184.
17. Fluor Daniel, Inc. Evaluation of Lead Emission Controls at the Doe
Run Company's Primary Lead Smelter at Heculaneum, Missouri. Redwood
City, California. July 17, 1989. pp. 4.8 to 4.12.
18. Emmel, B., and A. J. Miles (Radian). Evaluation of Lead Emission
Controls at ASARCO's Primary Lead Smelter at Glover, Missouri.
Prepared for U. S. Environmental Protection Agency, Region VII,
Kansas City, Missouri. Contract No. 68-02-3513, WA 58, and
No. 68-02-3881, WA01. March 22, 1985. pp. 17 to 20.
19. Reference 13, p. 7.6-3.
20. Reference 13, p. 7.6-4.
21. Technical Guidance for Control of Industrial Process Fugitive
Particulate Emissions. U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina. Publication
No. EPA-450/3-77-010. March 1977. pp. 2-134 to 2-139.
22. Reference 2, p. 4.3-20.
23. Memorandum from Vaught, C. (Midwest Research Institute), to
Scott, D., EPA:AQMD. September 21, 1990. Report on August 8, 1990,
trip to Plant A.
24. Memorandum from Vaught, C. (Midwest Research Institute), to
Scott, D., EPA:AQMD. September 21, 1990. Report on August 9, 1990,
trip to Plant B.
25. Reference 23.
26. Reference 24.
27. Reference 17, p. 4.11.
28. Reference 23.
29. Reference 24.
30. Reference 2, pp. 4.3-22 to 4.3-23.
31. Rives, G. D., and A. J. Miles (Radian). Control of Arsenic Emissions
from the Secondary Lead Industry-Technical Document. Prepared for
the U. S. Environmental Protection Agency. EPA Contract
No. 68-02-3816. Research Triangle Park, North Carolina. March 18,
1985. p. 7.
103
-------
32. Reference 31, Appendix A.
33. Reference 13, p. 7.11-2.
34. Reference 31, p. 13.
35. Elliott, J. A., and A. J. Miles (Radian). Evaluation of Implemented
Process and Fugitive Lead Emission Controls at Refined Metals
Corporation, Memphis, Tennessee. Prepared for the U. S.
Environmental Protection Agency. Atlanta, Georgia. September 15,
1989. 84 p.
36. Fuchs, M. R., M. J. Krall, and G. D. Rives (Radian). Emission Test
Report: Chloride Metals Secondary Smelter, Tampa, Florida. Prepared
for U. S. Environmental Protection Agency, EPA Contract
No. 68-02-3850. Research Triangle Park, North Carolina. March 14,
1985. 131 p.
37. Midwest Research Institute. Development of New Source Performance
Standards for Secondary Lead Smelting Industry. Prepared for the
U. S. Environmental Protection Agency. EPA Contract No. 68-02-3059.
Research Triangle Park, North Carolina. May 30, 1980.
38. Burton, D. J., R. T. Coleman, W. M. Coltharp, J. R. Hoover, and
R. Vandercort (Radian). Control Technology Assessment: The
Secondary Nonferrous Smelting Industry. Prepared for the U.S.
Department of Health and Human Services. NIOSH Contract
No. 200-77-0008. Cincinnati, Ohio. October 1980.
39. Prengaman, R. D. Reverberatory Furance—Blast Furnace Smelting of
Battery Scrap at RSR. In: Lead-Zinc-Tin 1980, J. H. Cigan,
T. S. Mackley, and T. J. O'Keefe (eds.). A Publication of The
Metallurgical Society of AIME. December 3, 1979. p. 991-993.
40. Coleman, R., Jr., and R. Vandervort. Demonstration of Fugitive
Emission Controls at a Secondary Lead Smelter. In: Lead-Zinc.-Tin
1980, Proceedings of TMS-AIME World Symposium on Metallurgy and
Environmental Control. Las Vegas, Nevada. J. M. Cigan,
T. S. Mackey, and T. J. O'Keefe (eds.). February 24-28, 1980.
41. Reference 31, p. 22.
42. Reference 21, p. 2-177 to 2-180.
43. Reference 31, p. 73.
44. Reference 35.
45. Reference 36.
46. Reference 31, p. 32.
104
-------
47. Reference 35, p. 4-6.
48. Review of New Source Performance Standards for Lead-Acid Battery
Manufacture. (Preliminary Draft). U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina. October 1989.
pp. 3-7 to 3-23.
49. Compilation of Air Pollutant Emission Factors, Volume I: Stationary
Point and Area Sources. U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina. Publication No. AP-42.
August 1982. p. 7.15-2.
50. Reference 48, pp. 3-16 to 4-8.
51. Memo from Michelitsch, D. M., EPA:ISB, to Durkee, K. R., EPA:ISB.
October 18, 1988. Report on July 20, 1988, trip to Douglas Battery
Manufacturing Company, Winston-Salem, North Carolina.
52. Memo from Michelitsch, D. M., EPArlSB, to Ourkee, K. R., EPArlSB.
November 1, 1988. Report on July 26, 1988, trip to Exide
Corporation, Reading, Pennsylvania.
53. Memo from Michelitsch, D. M., EPA:ISB, to Durkee, K. R., EPA:ISB.
November 7, 1988. Report on July 13, 1988, trip to Trojan Battery
Manufacturing Company, Lithonia, Georgia.
54. Memo from Michelitsch, D. M., EPArlSB, to Durkee, K. R., EPA:ISB.
December 6, 1988. Report on July 19, 1988, trip to Johnson Controls,
Incorporated, Winston-Salem, North Carolina.
55. Memo from Michelitsch, D. M., EPA:ISB, to Durkee, K. R., EPA.-ISB.
December 6, 1988. Report on July 27, 1988, trip to East Penn
Manufacturing Company, Lyon Station, Pennsylvania.
56. Memo from Michelitsch, D. M., EPA:ISB, to Durkee, K. R., EPArlSB.
January 9, 1989.. Report on July 12, 1988, trip to C&D Charter Power
Systems, Inc., Conyers, Georgia.
57. Reference 48, pp. 3-16 to 4-8.
58. Reference 12, pp. 7 to 9.
59. Reference 12, p. 10.
60. Reference 12, p. 12.
61. Reference 12, pp. 17 to 18.
62. Reference 13, p. 7.10-10.
63. Reference 23.
105
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64. Reference 24.
65. Reference 13, p. 7.6-9.
66. Reference 13, p. 7.6-10.
67. Reference 13, p. 7.6-12.
68. Reference 13, p. 7.6-11.
69. Reference 13.
70. Reference 31.
71. Reference 3, p. 2-9.
72. Reference 3, p. 2-7.
73. Reference 3, p. 3-7.
74. Reference 3, p. 3-18.
75. Reference^, p. 4-19.
76. Reference 40, p. 663.
77. Reference 40, p. 603.
78. Reference 40, p. 662.
79. Keller, L. E., and A. J. Miles (Radian). Study of Lead Emissions
from the Refined Metals Corporation Facility in Memphis, Tennessee.
EPA Contract No. 68-02-3889. Research Triangle Park, North
Carolina. July 1986. p. 5-9.
80. Reference 79, p. 5-7.
81. Reference 38, p. 312.
82. Reference 38, p. 324.
83. Smith, R. D., 0. A. Kiehn, D. R. Wilburn, and R. C. Bowyer. Lead
Reduction in Ambient Air: Technical Feasibility and Cost Analysis of
Domestic Primary Lead Smelters and Refineries. Bureau of Mines, U.S.
Department of the Interior. Washington, D.C. 1987. p. 9.
84. Reference 23.
85. Reference 24.
86. Reference 18, p. 64.
106
-------
87. Reference 17, pp. 4.1 to 4.24.
88. Reference 18, p. 64.
89. Reference 17, p. 4.1 to 4.24.
90. Reference 18, p. 4.1 to 4.29.
91. Reference 83, p. 13 to 14.
92. Reference 83, p. 9.
93. Reference 31, pp. 70 to 75.
94. Reference 31, Appendix A.
95. Reference 31, pp. 61 to 70.
96. Reference 79, p. 5-11.
97. Reference 79, p. 5-12.
98. Reference 31, p. 264-265.
99. Reference 38, p. 266.
107
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APPENDIX A.
PROCEDURES FOR SAMPLING SURFACE/BULK MATERIALS
-------
APPENDIX A. PROCEDURES FOR SAMPLING SURFACE/BULK MATERIALS
(Note: The material presented in this appendix is taken directly
from Appendix D of "Control of Open Fugitive Dust Sources," EPA
Publication No. EPA-450/3-88-008.)
The starting point for developing the recommended procedures for
collecting road dust and aggregate material samples was a review of
American Society of Testing and Materials (ASTM) Standards. When
practical, the recommended procedures were structured identically to the
ASTM standard. When this was not possible, an attempt was made to develop
the procedure in a manner consistent with the intent of the majority of
pertinent ASTM Standards.
A.I UNPAVED ROADS
The main objective in sampling the surface material from an unpaved
road is to collect a minimum gross sample of 23 kg (50 Ib) for every
3.8 km (3 miles) of unpaved road. The incremental samples from unpaved
roads should be distributed over the road segment, as shown in Figure A-
1. At least four incremental samples should be collected and composited
to form the gross sample.
The loose surface material is removed from the hard road base with a
whisk broom and dustpan. The material should be swept carefully so that
the fine dust is not injected into the atmosphere. The hard road base
below the loose surface material should not be abraded so as to generate
more fine material than exists on the road in its natural state.
Figure A-2 presents a data form to be used for the sampling of
unpaved roads.
A.2 PAVED ROADS
Ideally, for a given paved road, one gross sample per every 8 km
(5 miles) of paved roads should be collected. For industrial roads, one
gross sample should be obtained for each road segment in the plant. The
gross sample should consist of at least two separate increments per travel
lane, or each 0.5 mile length should have a separate sample.
Figure A-3 presents a diagram showing the location of incremental
samples for a four-lane road. Each incremental sample should consist of a
lateral strip 0.3 to 3 m (1 to 10 ft) in width across a travel lane. The
A-l
-------
I
IN)
L = 4.8km (3 Ml.)
T
K-
W = 9.1 m(30 ft.)
Sample Strip
20cm (8 in.) Wide
L = 1.6km (1 Mi.)
Figure A-l. Location of incremental sampling sites on an unpaved road.
-------
Sample
No.
Time
Location*
Surface
Area
Depth
Quantity
of Sample
'Use code given on plant map for segment identification
and indicate sample location on map.
Figure A-2. Sampling data form for unpaved roads.
A-3
-------
— 8km (5 Ml.) of similar road type
8
Increment 1
Figure A-3. Location of incremental sampling sites on a paved road.
-------
exact width is dependent on the amount of loose surface material on the
paved roadway. For a visually dirty road, a width of 0.3 m (1 ft) is
sufficient; but for a visually clean road, a width of 3 m (10 ft) is
needed to obtain an adequate sample.
The above sampling procedure may be considered as the preferred
method of collecting surface dust from paved roadways. In many instances,
however, collecting eight sample increments may not be feasible due to
manpower, equipment, and traffic/hazard limitations. As an alternative
method, samples can be obtained from a single strip across all the travel
lanes. When it is necessary to resort to this sampling strategy, care
must be taken to select sites that have dust loading and traffic
characteristics typical of the entire roadway segment of interest. In
this situation, sampling from a strip 3 to 9 m (10 to 30 ft) wide is
suggested. From this width, a sufficient representative sample can be
collected.
Samples are removed from the road surface by vacuuming, preceded by
broom sweeping if large aggregate is present. The samples should be taken
from the traveled portion of the lane with the area measured and recorded
on the appropriate data form. With a whisk broom and a dust pan, the
larger particles are collected from the sampling area and placed in a
clean, labeled container (plastic jar or bag). The remaining smaller
particles are then swept from the road with an electric broom-type vacuum
sweeper. The sweeper must be equipped with a preweighed, prelabeled,
disposable vacuum bag. Care must be taken when installing the bags in the
sweeper to avoid torn bags, which can result in loss of sample. After the
sample has been collected, the bag should be removed from the sweeper,
checked for leaks, and stored in a prelabeled, gummed envelope for
transport. Figure A-4 presents a data form to be used for the sampling of
paved roads.
Values for the dust loading on only the traveled portion of the
roadway are needed for inclusion in the appropriate emission factor
equation. Information pertaining to dust loading on curb/beam and parking
areas is necessary in estimating carry-on potential to determine the
appropriate industrial road augmentation factor.
A-5
-------
Type of Material Sampled:.
Site of Sampling:
Type of Pavement:
_No. of Traffic Lanes.
Surface Condition
Sample No.
Vac. Bag
Time
Location*
Sample Area
Broom
Swept?
|y/n)
*Use code given on plant map for segment identification
and indicate sample location on map.
Figure A-4. Sampling data form for paved roads,
A-6
-------
A.3 STORAGE PILES
• In sampling the surface of a pile to determine representative
properties to use in the wind erosion equation, a gross sample made up of
top, middle, and bottom incremental samples should ideally be obtained
since the wind disturbs the entire surface of the pile. However, it is
impractical to climb to the top or even middle of most industrial storage
piles because of their large size.
The most practical approach in sampling from large piles is to
minimize the bias by sampling as near to the middle of the pile as
practical and by selecting sampling locations in a random fashion.
Incremental samples should be obtained along the entire perimeter of the
pile. The spacing between the samples should be such that the entire pile
perimeter is traversed with approximately equidistant incremental
samples. If small piles are sampled, incremental samples should be
collected from the top, middle, and bottom.
An incremental sample (e.g., one shovelful) is collected by skimming
the surface of the pile in a direction upward along the face. Every
effort must be made by the person obtaining the sample not to purposely
avoid sampling larger pieces of raw material. Figure A-5 presents a data
form to be used for the sampling of storage piles.
In obtaining a gross sample to characterize a load-in or load-out
process, incremental samples should be taken from the portion of the
storage pile surface: (1) that has been formed by the addition of aggre-
gate material or (2) from which aggregate material is being reclaimed.
A-7
-------
Type of Material Sampled:.
Site of Sampling:
SAMPLING METHOD
1. Sampling device: pointed shovel
2. Sampling depth: 10-15cm (4-6inches)
3. Sample container: metal or plastic bucket with sealed poly liner
4. Gross sample specifications:
(a) 1 sample of 23kg (50lb.) minimum for every pile sampled
(b) composite of 10 increments
5. Minimum portion of stored material (at one site) to be sampled: 25%
SAMPLING DATA
Sample
No.
Time
Location (refer to map)
Surface
Area
Depth
Quantity
of Sample
Figure A-5. Sampling data form for storage piles.
A-8
-------
APPENDIX B.
PROCEDURES FOR LABORATORY ANALYSIS OF SURFACE/BULK SAMPLES
-------
APPENDIX B. PROCEDURES FOR LABORATORY ANALYSIS OF SURFACE/BULK SAMPLES
(Note: The material presented in this appendix is taken directly
from Appendix E of "Control of Open Fugitive Dust Sources," EPA
Publication No. EPA-450/3-88-008.)
B.I SAMPLES FROM SOURCES OTHER THAN PAVED ROADS -
B.I.I Sample Preparation
Once the 23 kg (50 Ib) gross sample is brought to the laboratory, it
must be prepared for silt analysis. This entails dividing the sample to a
workable size.
A 23 kg (50 Ib) gross sample can be divided by using: (1) mechanical
devices; (2) the alternative shovel method; (3) a riffle; or (4) the
coning and quartering method. Mechanical division devices are not
discussed in this section since they are not found in many laboratories.
The alternative shovel method is actually only necessary for samples
weighing hundreds of pounds. Therefore, this appendix discusses only the
use of the riffle and the coning and quartering method.
The ASTM standards describe the selection of the correct riffle size
and the correct use of the riffle. Riffle slot widths should be at least
three times the size of the largest aggregate in the material being
divided. The following quote describes the use of the riffle.1
"Divide the gross sample by using a riffle. Riffles
properly used will reduce sample variability but cannot
eliminate it. Riffles are shown in Figure B-l, (a) and (b).
Pass the material through the riffle from a feed scoop, feed
bucket, or riffle pan having a lip or opening the full length
of the riffle. When using any of the above containers to feed
the riffle, spread the material evenly in the container, raise
the container, and hold it with its front edge resting on top
of the feed chute, then slowly tilt it so that the material
flows in a uniform stream through the hopper straight down
over the center of the riffle into all the slots, thence into
the riffle pans, one-half of the sample being collected in a
pan. Under no circumstances shovel the sample into the riffle
riffle, or dribble into the riffle from a small-mouthed
container. Do not allow the material to build up in or above
the riffle slots. If it does not flow freely through the
slots, shake or vibrate the riffle to facilitate even flow."
B-l
-------
reed Cnure
Riffle Scmpier
(a)
Riffle Sucker and
Seperafe read Chufe Stand
Co)
Figure 8-1. Sample dividers (riffles).
B-2
-------
Figure B-2. Coning and quartering.
8-3
-------
The procedure for coning and quartering is best illustrated in
Figure B-2. The following is a description of the procedure: (1) mix the
material and shovel it into a neat cone; (2) flatten the cone by pressing
the top without further mixing; (3) divide the flat circular pile into
equal quarters by cutting or scraping out two diameters at right angles;
(4) discard two opposite quarters; (5) thoroughly mix the two remaining
quarters, shovel them into a cone, and repeat the quartering and
discarding procedures until the sample has been reduced to 0.9 to 1.8 kg
(2 to 4 Ib). Samples likely to be affected by moisture or drying must be
handled rapidly, preferably in an area with a controlled atmosphere, and
sealed in a container to prevent further changes during transportation and
storage. Care must be taken that the material is not contaminated by
anything on the floor or that a portion is not lost through cracks or
holes. Preferably, the coning and quartering operation should be
conducted on a floor covered with clean paper. Coning and quartering is a
simple procedure that applies to all powdered materials and to sample
sizes ranging from a few grams to several hundred pounds.2
The size of the laboratory sample is important—too little sample
will not be representative, and too much sample will be unwieldly.
Ideally, one would like to analyze the entire gross sample in batches, but
this is not practical. While all ASTM standards acknowledge this
impracticality, they disagree on the exact size, as indicated by the range
of recommended samples, extending from 0.05 to 27 kg (0.1 to 60 Ib).
The main principle in sizing the laboratory sample is to have
sufficient coarse and fine portions to represent the material and to allow
sufficient mass on each sieve so that the weighing is accurate. A
recommended rule of thumb is to have twice as much coarse sample as fine
sample. A laboratory sample of 800 to 1,600 g is recommended, since that
is the largest quantity that can be handled by the scales normally
available (1,600-g capacity). Also, more sample than this can produce
screen blinding for the 8 in. diameter screens normally available.
B.I.2 Laboratory Analysis of Samples for Silt Content
The basic recommended procedure for silt analysis is mechanical, dry
sieving after moisture analysis. A step-by-step procedure is given in
Tables B-l and B-2. The sample should be oven dried for 24 h at 230°F
B-4
-------
TABLE B-l. MOISTURE ANALYSIS PROCEDURE
1. Preheat the oven to approximately 110°C (230°F). Record oven
temperature.
2. Tare the laboratory sample containers that will be placed 1n the
oven. Tare the containers with the lids on if they have lids. Record
the tare weight(s). Check zero before weighing.
3. Record the make, capacity, smallest division, and accuracy of the
scale.
4. Weigh the laboratory sample in the container(s). Record the combined
weight(s). Check zero before weighing.
5. Place sample in oven and dry overnight.d
6. Remove sample container from oven and (a) weigh immediately if
uncovered, being careful of the hot container, or (b) place tight-
fitting lid on the container and let cool before weighing. Record the
combined sample and container weight(s). Check zero before weighing.
7. Calculate the moisture as the initial weight of the sample and
container minus the oven-dried weight of the sample and container
divided by the initial weight of the sample alone. Record the value.
8. Calculate the sample weight to be used in the silt analysis as the
oven-dried weight of the sample and container minus the weight of the
container. Record the value.
dDry materials composed of hydrated minerals or organic materials like
coal and certain soils for only 1-1/2 h. Because of this short drying
time, material dried for only 1-1/2 h must not be more than 2.5 cm
(1 in.) deep in the container.
B-5
-------
TABLE B-2. SILT ANALYSIS PROCEDURES
1. Select the appropriate 8-in. diameter, 2-in. deep sieve sizes. Recom-
mended U.S. Standard Series sizes are: 3/8 in., No. 4, No. 20,
No. 40, No. 100, No. 140, No. 200, and a pan. Comparable Tyler Series
sizes can also be used. The No. 20 and the No. 200 are mandatory.
The others can vary the recommended sieves are not available or if
buildup on one particulate sieve during sieving indicates that an
intermediate sieve should be inserted.
2. Obtain a mechanical sieving device such as vibratory shaker or a Roto-
Tap.
3. Clean the sieves with compressed air and/or a soft brush. Material
lodged in the sieve openings or adhering to the sides of the sieve
should be removed (if possible) without handling the screen roughly.
4. Obtain a scale (capacity of at least 1,600 g) and record make,
capacity, smallest division, date of last calibration, and accuracy
(if available).
5. Tare sieves and pan. Check the zero before every weighing. Record
weights.
6. After nesting the sieves in decreasing order with pan at the bottom,
dump dried laboratory sample (immediately after moisture analysis)
into the top sieve. Brush fine material adhering to the sides of the
container into the top sieve, and cover the top sieve with a special
lid normally purchased with the pan.
7. Place nested sieves into the mechanical device and sieve for 20 min.
Remove pan containing minus No. 200 and weigh. Replace pan beneath
the sieves and sieve for another 10 min. Remove pan and weigh. When
the differences between two successive pan sample weighings (where the
tare of the pan has been subtracted) is less than 3.0 percent, the
sieving is complete.
8. Weigh each sieve and its contents and record the weight. Check the
zero before every weighing.
9. Collect the laboratory sample and place the sample in a separate
container if further analysis is expected.
B-6
-------
before sieving. The sieving time is variable; sieving should be continued
until the net sample weight collected in the pan increases by less than
3.0 percent of the previous net sample weight collected in the pan. A
minor variation of 3.0 percent is allowed, since some sample grinding due
to interparticle abrasion will occur, and consequently, the weight will
continue to increase. When the change reduces to 3.0 percent, it is
thought that the natural silt has been passed through the No. 200 sieve
screen and that any additional increase is due to grinding.
Both the sample preparation operations and the sieving results can be
recorded on Figures B-3 and B-4.
B.2 SAMPLES FROM PAVED ROADS
B.2.1 Sample Preparation and Analysis for Total Loading
The gross sample of paved road dust will arrive at the laboratory in
two types of containers: (1) the broom-swept dust will be in plastic
bags, and (2) the vacuum-swept dust will be in vacuum bags.
Both the broom-swept dust and the vacuum-swept dust are weighed on a
beam balance. The broom-swept dust is weighed in a tared container. The
vacuum-swept dust is weighed in the vacuum bag that was tared and
equilibrated in the laboratory before going to the field. The vacuum bag
and its contents should be equilibrated again in the laboratory before
weighing.
The total surface dust loading on the traveled lanes of the paved
road is then calculated in units of kilograms of dust on the traveled
lanes per kilometer of road. When only one strip of length is taken
across the traveled lanes, the total dust loading on the traveled lanes is
calculated as follows:
m,-HTI
L = ±JL (B-l)
where:
mjj = mass of the broom swept dust, kg;
mv = mass of the vacuum swept dust, kg; and
8, = length of strip as measured along the centerline of the road,
km.
B-7
-------
Sample No.:.
Material:
Split Sample Balance:
Make
Capacity
Smallest Division.
Total Sample Weight:.
[Excl. Container]
Number of Splits:
Split Sample Weight (before drying)
Pan + Sample:^
Pan:
Wet Sample:
Oven Temperature:.
Date In
Time In
Drying Time_
.Date Out_
Time Out
Material Weight (after drying)
Pan + Material:
Pan:__
Dry Sample:.
MOISTURE CONTENT:
(A) Wet Sample Wt.
(B) Dry Sample Wt.
(C) Difference Wt.
C * 100/A=
Moisture
Figure B-3. Sample moisture analysis form.
B-8
-------
Sample No..
Material:
Split Sample Balance:
Make
Capacity
Smallest Division.
Material Weight (after drying)
Pan * Material:
Pan:
Dry Sample:.
Final Weight:.
Net Weight < 200 'Mesh
Total Net Weight
' 100'
SIEVING
Time: Start:
Initial (Tare):
20 min:
30 min:
40 min:
Weight (Pan Only)
SIZE DISTRIBUTION
Screen
3/8 in.
4 mesh
1 0 mesh
20 mesh
40 mesh
100 mesh
140 mesh
200 mesh
Pan
Tare Weight
(Screen)
Final Weight
(Screen + Sample)
Net Weight (Sample)
-
%
Figure B-4. Sample silt analysis form.
B-9
-------
When several incremental samples are collected on alternate roadway
halves as shown in Figure B-3, the total surface dust loading is
calculated as follows:
m, ,-HH ,+m, -HTI
- b vl b5 v5
i +i
1 5
where:
m^. = mass of broom sweepings for increment i, kg;
my = mass of vacuum sweepings for increment i, kg; and
i = length of increment i is measured along the road center line,
km.
B.2.2 Sample Preparation and Analyses for Road Dust Silt Content
After weighing the sample to calculate total surface dust loading on
the traveled lanes, the broom-swept and vacuum-swept dust is composited.
The composited sample is usually small and requires no sample splitting in
preparation for sieving. If splitting is necessary to prepare a
laboratory sample of 800 to 1,600 g, the techniques discussed in
Section B.I.I can be used. The laboratory sample is then sieved using the
techniques described in Section B.I. 2.
B.3 REFERENCES FOR APPENDIX B
1. D2013-72. Standard Method of Preparing Coal Samples for Analysis.
Annual Book of ASTM Standards, 1977.
2. Silverman, L., et al. Particle Size Analysis in Industrial Hygiene,
Academic Press, New York, 1971.
B-10
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APPENDIX C.
PROCEDURES FOR ESTIMATING LEAD EMISSIONS FROM
OPEN FUGITIVE DUST SOURCES
-------
APPENDIX C. PROCEDURES FOR ESTIMATING LEAD EMISSIONS FROM
OPEN FUGITIVE DUST SOURCES
This appendix consists of four tables that summarize the procedures
in step-by-step format for estimating open fugitive dust lead emissions.
Tables C-l to C-4 give procedures for estimating lead emissions from paved
roads, unpaved roads, storage pile materials handling operations, and
storage pile wind erosion, respectively. A recommended method for
determining the values of the emission factor parameters is provided for
each of the estimation methods presented in the tables. Each table also
includes default values or default methods for a number of the parameters
used in the emission factor equations. Where available, these default
values are provided for both primary and secondary lead smelters. In all
cases, site-specific data should be used in the emission factor
equations. However, if site-specific data are not available, the default
values referenced in the tables should provide reasonable estimates of
these parameters.
C-l
-------
TABLE C-l. SUMMARY OF PROCEDURES FOR ESTIMATING FUGITIVE LEAD EMISSIONS FROM PAVED ROADS
AT PRIMARY AND SECONDARY LEAD SMELTERS
Step
Default value/method
Recommended method
Primary lead
Secondary lead
i
ro
1. Identify paved road
2. Determine Industrial augmentation
factor (I)
3. Determine number of traffic lanes (n)
4. Determine surface dust loading (L)
5. Determine silt content (s) of surface
loading
6. Determine lead content (C) of silt
7. Determine mean vehicle weight (W)
8. Determine emission factor (EF) using
Equation I
From plant map, tour
Table 2
Plant map, tour
Sample road dust (Appendix A)
Lab analysis (Appendix B)
Lab analysis
Plant records
= o.22(,
n = 2
Table 6
Table 6
Table 6
Table 6
0.7
n = 2
Tables 11, 12
Tables II, 12
Tables 11, 12
9.
10.
11.
12.
13.
14.
Determine average distance
travel led (D) per trip
Determine traffic volume (NV)
Determine total vehicle kilometers
travelled (VKT)
Determine uncontrol led lead
emissions (E)
Determine control efficiency (e)
Determine controlled emissions (E )
Measure actual distance
Plant records
VKT = (D)(NV)
E = (EFMVKT)
Table 19
Ec - E(' - 100>
Estimate from map Estimate from map
-------
TABLE C-2. SUMMARY OF PROCEDURES FOR ESTIMATING FUGITIVE LEAD EMISSIONS FROM UNPAVED ROADS
AT PRIMARY AND SECONDARY LEAD SMELTERS
Step
Default value/method
Recommended method
Primary lead
Secondary Iead
i
co
1. Identify unpaved road
2. Determine silt content (s) of road
surface
3. Determine lead content (C) of silt
4. Determine mean vehicle speed (S)
5. Determine mean vehicle weight (W)
6. Determine mean number of wheels (w)
7. Determine number of wet days (p)
6. Determine emission factor (EF) using
Equation 2
9. Determine average distance travelled
(D) per trip
10. Determine traffic volume (NV)
It. Determine total vehicle kilometers
traveled (VKT)
12. Determine uncontrolled lead
emissions (E)
13. Determine control efficiency (e)
14. Determine controlled lead
emissions (E )
From plant map, tour
Sample/analyze surface material
(Appendix A/Append Ix B)
Lab analyses
Plant records
Plant records
Plant records
Meteorological records
Plant records .
Plant records
VKT = (D)(NV)
E =
-------
TABLE C-3. SUMMARY OF PROCEDURES FOR ESTIMATING FUGITIVE LEAD EMISSIONS FROM STORAGE PILE
MATERIALS HANDLING AT PRIMARY AND SECONDARY LEAD SMELTERS
Step
Recommended method
Default value/method
Primary lead
Secondary lead
1. Identify storage pile
2. Determine moisture content (M) of
material
3. Determine silt content (s) of material
4. Determine lead content (C) of silt
5. Determine mean Mind speed (U)
Plant map, tour
Sample/analyze material
(Appendix A/Appendix B)
Lab analysis (Appendix B)
Lab analysis
From meteorological records
Table 15
Table 15
Table 15
5 to 20 km/h
Table 11
5 to 20 km/h
6. Determine emission factor (EF) using
Equation 3
EF = 0.0016)
1.3
1.4
7. Determine total amount of material
handled (T)
8. Determine lead emissions (E)
9. Determine control efficiency (e)a
10. Determine controlled emissions (E )
From plant records
E = (EF)(T)
40 to 90 percent (chemical stabilization)
60 to 80 percent (wind fences)
40 to 75 percent (wet spray)
up to 90 percent (foam)
Reference for control efficiencies: Control of Open Fugitive Dust Sources. EPA Publication No. EPA-450/3-88-008.
-------
TABLE C-4. SUMMARY OF PROCEDURES FOR ESTIMATING FUGITIVE LEAD EMISSIONS FROM STORAGE PILE
WIND EROSION AT PRIMARY AND SECONDARY LEAD SMELTERS
Step
Recommended method
Default value/method
Primary lead
Secondary lead
t. Identify storage pile
2. Determine silt content (s) of
material
3. Determine lead content (C) of silt
4. Determine number of wet days per year
5. Determine percentage of time (f) wind
speed exceeds 5.4 m/s at mean pile
height
6. Determine emission factor (EF) using
Equation 4
Plant map, tour
Sample/analyze material
(Appendix A/Append Ix B)
Lab analysis
From meterologlcal records
From meterological records
EF =
Table 15
Table 15
Figure 1
Table 11
Figure 1
n
i
en
7. Determine area (A) of storage pile
8. Determine lead emissions
9. Determine control efficiency (e)a
10. Determine controlled emissions (E )
Measure area
E = (EF)(A)
40 to 90 percent (chemical stabilization)
60 to 80 percent (wind fences)
40 to 75 percent (wet spray)
up to 90 percent (foam)
-)
From plant map
From plant map
Reference for control efficiencies: Control of Open Fugitive Dust Sources. EPA Publication No. EPA-450/3-88-008.
-------
APPENDIX D.
EXAMPLE FUGITIVE EMISSION INVENTORY CALCULATIONS
HYPOTHETICAL SECONDARY LEAD SMELTER
-------
Scenario: Facility A is a secondary lead smelter located in West
Helena, Arkansas. The facility has a lead production capacity of
23,000 tons per year. It operates a blast furnace with the capacity of
20,000 tons per year, three 100-ton kettles and two 50-ton kettles. These
kettles can produce 23,000 tons per year. The facility typically operates
at capacity and produces nearly equal amounts of hard and soft lead. All
shipping and receiving operations at the plant are by truck, and materials
are transferred internally with a combination of front-end loader and
forklift. The primary exception is the flue dust from the blast furnace
fabric filter, which is transported directly to a storage silo by screw
conveyor. All materials are stored within enclosed areas except recycle
and waste slag, which is stored in open storage piles. The facility has
no collection system for blast furnace charging, tapping emissions, or the
refining kettle operations.
Problem: Develop a preliminary fugitive emission inventory using
readily available emission factors, process data supplied by the plant,
and limited sampling of surface materials around the plant.
Step 1: Identify Major Fugitive Emission Sources
Work with plant personnel to develop: (1) a facility plot plan that
shows major facility traffic patterns and open areas and storage piles
that may be subject to wind erosion and (2) a simplified materials flow
diagram that shows typical annual levels of raw materials, intermediates,
and finished product. Then use these documents to develop a list of
potentially significant fugitive emission sources. Figure D-l shows a
hypothetical plot plan for Facility A. The major potential fugitive
emission sources are listed below.
1. Open dust sources
a. Raw material delivery trucks
b. Product delivery trucks
c. Internal transport
d. Slag storage area
e. Open area wind erosion (north yard)
D-l
-------
i
ro
f
1 Main plant roadway
2 North plant yard
3 Casting building
4 Raw material storage
5 Battery breaking building
6 South plant yard
*¥rtvi' ' AH
Figure D-l. Plot plan for Facility A.1
-------
2. Process fugitives
a. Blast furnace charging and tapping
b. Refining kettle operations
c. Lead casting
Step 2: Define Emissions Calculation Procedures
Generally, the emission factor equations for open dust sources and
the emission factors for process fugitive sources presented in Section 3
of this document can be used to develop a preliminary fugitive emission
inventory. The appropriate procedures for the eight sources identified
above are tabulated below:
Raw material delivery trucks, product delivery trucks, and internal
transport.
E = 0.022
where:
E = lead emissions, Ib/yr;
I = industrial augmentation factor;
C = lead content of silt, percent;
n = number of traffic lanes;
s = surface material silt content, percent;
L = surface loading, Ib/mile;
W = average vehicle weight, ton; and
VMT = vehicle miles traveled per year.
-- Slag storage pile (handling)
where:
E = lead emissions, Ib/yr;
C = lead content, percent;
U = mean wind speed, mi/hr;
M = material moisture content, percent; and
P = process rate, ton/yr.
0-3
-------
— Slag storage and north yard (wind erosion)
where:
E = lead emissions, Ib/day;
C = lead content of surface, percent;
s = silt content, percent;
p = number of days with >0.01 in. precipitation per year;
f = percentage of time mean wind speed exceeds 12 mi/hr at mean pile
height; and
A = surface area (acres).
— Blast furnace charging and tapping
E = 3.2 P to 7.0 P
where:
E = lead emission rate, Ib/yr, and
P = production rate (tons Pb produced/yr) .
— Refining kettle
E = 0.012 P
where:
E = lead emission rate, Ib/yr, and
P = finished lead production rate, tons/yr.
— Casting
E = 0.0014 P
D-4
-------
where:
E = lead emission rate, Ib/yr, and
P = finished lead production rate.
Step 3: Compile Input Data
The third step in the inventory process is to compile the input data
needed to implement the models defined in Step 2. Generally, these input
data will be generated reviewing plant operating records, surveying plant
personnel about operating practices, reviewing National Weather Service
climatic records, and sampling and analysis activities. The discussion
below presents values for the hypothetical plant considered here and
describes how these data may be obtained for a typical plant.
1. Vehicular traffic. As defined in Section 2.1 of this document,
the industrial augmentation factor ranges from 1 to 7 depending on the
nature of the roadway traffic pattern. A value of 1 is suggested for
cases where traffic does not travel on unpaved areas and a factor of 7 is
suggested for roadways where traffic enters frequently from unpaved
areas. Because there are no unpaved areas subject to traffic at this
plant, a value of 1.0 is assumed.
The number of travel lanes (n) for the main plant roadway is two. As
described earlier, much of the internal transport occurs on open areas.
For this situation, the number of lanes is not defined. However, the road
was assumed to be 25 ft wide (two lanes) for purposes of calculating both
n and surface loading (L). This assumption will yield consistent
estimates.
The silt and lead content were estimated through an abbreviated
sampling and analysis program using the methods described in Appendices A
and B. The average silt content of the road dust was 15 percent while the
average silt content in the plant yard was 21 percent. The average lead
content of the areas was 34 percent for the road and 32 percent for the
yard area.
The average dust loading was 0.006 lb/ft2 for the road and
0.01 lb/ft2 for the plant yard. These dust loadings (assuming a 25 ft
road bed) convert to L = 792 Ib/mile for the roadway and L = 1,320 Ib/mile
for the plant yard.
D-5
-------
The average weight of transport vehicles (w) was discussed with plant
personnel. They estimate that the weight of vehicles used to delivery raw
materials and to ship products is 40 tons. The average weight of the
front-end loaders and fork lifts used for internal transport is 12 tons.
The total travel intensity was estimated based on plant records and
conversations with plant personnel. The average number of delivery trucks
that travel on plant roads are shown in Table D-l. The travel pattern
results in approximately 3,900 trips per year. Examination of plant maps
indicates that each round trip is about 1,300 ft or 0.25 miles in
length. Hence, total vehicle miles traveled per year is about 975. For
internal traffic, plant personnel indicate that three transport vehicles
operate during the first and second shifts and that one transport vehicle
operates during the third shift. The vehicles operate about 60 percent of
the time and at speeds of about 5 mi/hr. These vehicles account for about
120 vehicle miles per day, or about 44,000 vehicle miles per year.
2. Storage and wind erosion. The primary open dust emissions other
than from vehicular traffic are generated from slag storage operations.
An abbreviated sampling program indicated that the slag had a silt content
(s) of 12 percent, a moisture content (M) of 3 percent, and a lead content
(C) of 42 percent. Also, plant personnel indicate that about 750 Ib of
slag are produced for each ton of lead produced by the blast furnace.
Consequently, about 8,600 tons per year of slag are estimated to be
processed through storage. Visual examination of the storage pile during
a plant visit indicated that the storage pile and disturbed area
surrounding it covered an area 30 ft x 50 ft, or 0.034 acre. Finally,
data from the National Weather Service were examined to obtain estimates
of the number of days with more than 0.01 inch precipitation (p), the mean
wind speed (U), and the fraction of the time that the wind exceeds
12 mi/hr at mean pile height (f). These estimates are p = 115 days per
year, U = 5 mi/hr, and f = 1.2 percent.
The other potential source of open dust fugitive lead emissions is
wind erosion from the north plant yard. A review of the plant plot
diagram indicated that this yard covers an area of 0.25 acres. A limited
sampling and analysis program indicated that the surface material had a
silt content of 13 percent and a lead content of 43 percent. The number
of days that precipitation exceeds 0.01 inches is 115 days per year as
D-6
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TABLE D-l. SUMMARY OF DELIVERY TRUCK TRAFFIC AT FACILITY A
Material
Frequency
1. Batteries
2. Battery scrap
3. Coke
4. Scrap iron
5. Lime stone
6. Lead ingots to customer
5 trucks per day
25 trucks per week (Monday-Friday)
3 trucks per week
2 to 3 trucks per week
10 trucks per month
3 to 4 trucks per week
1 load per month
3 to 5 trucks per day
25 per week
NOTE: Average number of trucks using main roadway is 64 per week
(excluding slag trucking and lead ingots to customers).
D-7
-------
before. However, because the surface is at ground level rather than at an
average height of 6 ft, the fraction of time that the wind exceeds
12 mi/hr is estimated to be 0.4 percent.
3. Process fugitive emissions. The only data needed to estimate
process fugitive emission rates are the process rates for the blast
furnace and refining and casting operations. In order to estimate
emissions conservatively (high), the respective process capacities of
23,000 tons/yr per year should be used.
Step 4: Calculate Emission Levels
The emission models identified in Step 2 and input data defined in
Step 3 are used to calculate annual emission rates from each source.
These calculations are shown in Table D-2.
REFERENCES FOR APPENDIX D.
1. Keller, L. E., and A. J. Mikes (Radian). Study of Lead Emissions from
the Refined Metals Corporation Facility in Memphis, Tennessee. EPA
Contract No. 68-02-3889. Research Triangle Park, North Carolina.
July 1986. p. 4-6.
D-8
-------
TABLE D-2. CALCULATION OF FUGITIVE EMISSION RATES
Raw material and product delivery trucks
E • 0.022 I (i§oH£°''(VMT)
- 0.022 1 (T34)(|)(»)(TZ«_)(|0)«-'(975)
= 106 Ib/yr
Internal material transfer
E = 0.022 I °'
- 0.022 1 (
= 4,532 Ib/yr
Slag storage pile * handling
E- (0.0032) (-4)
100
(M/2) •
= (0.0032) (
= 6.6 Ib/yr
Slag storage pile: wind erosion
E - 1.7
12365-115wl.2
235
= 0.016 Ib/day
= 6.0 Ib/yr
(continued)
0-9
-------
TABLE D-2. (continued)
— North yard: wind erosion
, , , 43 w 13w365-115wQ.41/n
= L7 ^TOO^rS^ 235 K 15-] (0
= 0.045 Ib/day
= 16.4 Ib/yr
— Blast furnace charging and tapping
E = 5.1 P
= 5.1 (23,000)
= 117,300 Ib/yr
— Refinery kettle
E = 0.012 P
= 0.012 (20,000)
= 240 Ib/yr
~ Casting
E = 0.0014 p
= 0.0014 (20,000)
= 28 Ib/yr
D-10
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