Emission Factor Documentation for AP-42
Section 11.25
Clay Processing
Final Report
For U. S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emission Inventory Branch
EPA Contract 68-D2-0159
Work Assignment No. 1-01
MRI Project No. 4601-01
August 10, 1994
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Emission Factor Documentation for AP-42
Section 11.25
Clay Processing
Final Report
For U. S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emission Inventory Branch
Research Triangle Park, NC 27711
Attn: Mr. Ron Myers (MD-14)
Emission Factor and Methodology
EPA Contract 68-D2-0159
Work Assignment No. 1-01
MRI Project No. 4601-01
August 10, 1994
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PREFACE
This report was prepared by Midwest Research Institute (MRI) for the Office of Air Quality
Planning and Standards (OAQPS), U. S. Environmental Protection Agency (EPA), under Contract
No. 68-D2-0159, Work Assignment No. 1-01. Mr. Ron Myers was the requester of the work. The
report was prepared by Richard Marinshaw and Brian Shrager.
Approved for:
MIDWEST RESEARCH INSTITUTE
Roy Neulicht
Program Manager
Environmental Engineering
Department
Jeff Shular
Director, Environmental Engineering
Department
August 10, 1994
in
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CONTENTS
List of Figures .
List of Tables .
1. INTRODUCTION . . .
2. INDUSTRY DESCRIPTION
2.1
2.2
93
94
CHARACTERIZATION OF THE INDUSTRY
2.
2.
2.
2.
2.
2.
.1
.2
.3
.4
.5
.6
Kaolin
Ball Clay
Fire Clay
Bentonite
Fuller's Earth . . .
Common Clay and
Shale
PROCESS DESCRIPTION
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
Kaolin
Ball Clay
Fire Clay
Bentonite
Fuller's Earth . . .
Common Clay and
Shale
EMISSIONS
CONTROL TECHNOLOGY
3. GENERAL DATA REVIEW AND ANALYSIS
3.1 LITERATURE SEARCH AND SCREENING
3.2 EMISSION DATA QUALITY RATING SYSTEM . .
3.3 EMISSION FACTOR QUALITY RATING SYSTEM
4. AP-42 SECTION DEVELOPMENT
4.1 REVIEW OF SPECIFIC DATA SETS
4.
4.
4.
4.
4.
4.
4.
4.
4.
Reference 1
Reference 2
Reference 3
Reference 4
Reference 5
Reference 6
Reference 7
Reference 8
Reference 9
vn
vii
2
2
2
5
5
5
6
6
6
7
7
11
11
11
16
16
16
19
19
20
21
22
22
22
22
23
23
23
24
24
25
25
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CONTENTS (continued)
4.1.10 Reference 10 26
4.1.11 Review of XATEF and SPECIATE Data Base Emission Factors 26
4.1.12 Results of Data Analysis 26
4.1.13 Summary of Average Emission Factors 29
5. AP-42 SECTION 11.25 43
VI
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LIST OF FIGURES
Number
2-1 Process flow diagram for kaolin mining and dry processing
2-2 Process flow diagram for wet process kaolin for high grade products
2-3 Process flow diagram for ball clay processing
2-4 Process flow diagram for fire clay processing
2-5 Process flow diagram for bentonite processing
2-6 Process flow diagram for fuller's earth processing
2-7 Process flow diagram for common clay and shale processing
Pae
9
10
12
13
14
15
17
LIST OF TABLES
Number
2-1 Clays sold or used by producers in the United States in 1991 ....
2-2 End uses of clay produced or sold in the United States in 1991 . .
2-3 Clay processing operations
4-1 Summary of emission data for kaolin processing
4-2 Summary of particle size data for kaolin processing
4-3 Summary of emission data for ball clay processing
4-4 Summary of emission data for fire clay rotary dryers
4-5 Summary of trace element emission data for fire clay rotary dryers
4-6 Summary of particle size data for fire clay rotary dryers
4-7 Summary of test data for fire clay rotary calciners
4-8 Summary of trace elements data for fire clay rotary calciners ....
4-9 Summary of particle size data for fire clay rotary calciners
4-10 Summary of emission data for bentonite processing
4-11 Summary of particle size for benonite processing
4-12 Summary of emission data for Fuller's earth processing
4-13 Summary of emission factors for clay processing
Pae
3
4
8
27
28
28
30
31
33
34
35
36
38
39
39
40
vn
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EMISSION FACTOR DOCUMENTATION FOR AP-42 SECTION 11.25
Clay Processing
1. INTRODUCTION
The document "Compilation of Air Pollutant Emission Factors" (AP-42) has been published by
the U. S. Environmental Protection Agency (EPA) since 1972. Supplements to AP-42 have been
routinely published to add new emission source categories and to update existing emission factors.
AP-42 is routinely updated by EPA to respond to new emission factor needs of EPA, State, and local
air pollution control programs and industry.
An emission factor relates the quantity (weight) of pollutants emitted to a unit of activity of
the source. The uses for the emission factors reported in AP-42 include:
1. Estimates of areawide emissions;
2. Estimates of emissions for a specific facility; and
3. Evaluation of emissions relative to ambient air quality.
The purpose of this report is to provide background information from test reports and other
information to support preparation of AP-42 Section 11.25, Clay Processing.
This background report consists of five sections. Section 1 includes the introduction to the
report. Section 2 gives a description of the clay processing industry. It includes a characterization of
the industry, an overview of the different process types, a description of emissions, and a description
of the technology used to control emissions resulting from clay processing. Section 3 is a review of
emissions data collection and analysis procedures. It describes the literature search, the screening of
emission data reports, and the quality rating system for both emission data and emission factors.
Section 4 details the development of pollutant emission factors for the draft AP-42 section. It includes
the review of specific data sets and the results of data analysis. Section 5 presents AP-42 Section
11.25, Clay Processing.
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1,2
2. INDUSTRY DESCRIPTION
Clay is defined as a natural, earthy, fine-grained material composed largely of a group of
crystalline hydrous silicate minerals, known as clay minerals. Clay minerals are composed mainly of
silica, alumina, and water, but may also contain appreciable quantities of iron, alkalies, and alkaline
earths. Clay is formed by the mechanical and chemical breakdown of rocks. Clays are categorized
into six groups by the U.S. Bureau of Mines. The categories are kaolin, ball clay, fire clay, bentonite,
fuller's earth, and common clay and shale.
This section addresses emissions that result from the basic processing of clays that takes place
between the mining of the raw material and the production of the finished clay product. Emissions
from finished clay products are addressed under other AP-42 sections, including Section 11.3, Bricks
and Related Clay Products; Section 11.5, Refractory Manufacturing; Section 11.6, Portland Cement
Manufacturing, Section 11.7, Ceramic Clay Manufacturing; and Section 11.20, Lightweight Aggregate
Manufacturing. Clay sintering, which is no longer practiced in the United States, is addressed in
Section 11.8, Clay and Fly Ash Sintering.
The Standard Industrial Classification (SIC) code for mining, milling, and processing kaolin
and ball clay is 1455, Kaolin and Ball Clay; the SIC code for mining, milling, and processing fire
clay, bentonite, fuller's earth, and common clay and shale is 1459, Clay, Ceramic, and Refractory
Materials, Not Elsewhere Classified. The six-digit Source Classification Codes (SCC's) for clay
processing are as follows: 3-05-041 for kaolin processing, 3-05-042 for ball clay processing, 3-05-043
for fire clay processing, 3-05-044 for bentonite processing, 3-05-045 for fuller's earth processing, and
3-05-046 for common clay and shale processing.
1-3
2.1 CHARACTERIZATION OF THE INDUSTRY
Approximately 44 million megagrams (Mg) of clay were sold or used by domestic producers
in 1991. An estimated 319 companies operating more than 1,000 clay pits or mines in 44 States and
Puerto Rico reported clay production. Approximately 100 companies, most of which operate more
than one plant, accounted for approximately 66 percent of the tonnage and 75 percent of the value for
all types of clay produced and sold or used. Common clays and shale accounted for 62 percent of the
tonnage, and kaolin accounted for 61 percent of the value of clays produced in 1991. The eight
leading clay producing States, in descending order, were Georgia, Wyoming, Tennessee, Florida,
Illinois, Mississippi, California, and South Carolina. Table 2-1 summarizes 1991 domestic clay
production by State. The primary end uses of domestically produced clay are listed in Table 2-2. The
following paragraphs discusses the clay industry in more detail by clay type.
2.1.1 Kaolin
Kaolin, or china clay, is defined as a white, claylike material composed mainly of kaolinite,
which is a hydrated aluminum silicate (Al2O3-2SiO2-2H2O), and other kaolin-group minerals. Kaolin is
chemically inert over a relatively wide pH range and is white in color. Kaolin is an effective covering
agent when used as a pigment or extender in coated films and filling applications. In addition, kaolin
is soft, nonabrasive, and has a low conductivity of heat and electricity. As a result, kaolin has wide
variety of industrial applications.
Total domestic production of kaolin in 1991 amounted to 9,575,000 Mg. Forty-two firms
operated 141 kaolin mines in 14 States, and three large, diversified firms accounted for about
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TABLE 2-1. CLAYS SOLD OR USED BY PRODUCERS IN THE
UNITED STATES IN 1991"
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missoun
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Puerto Rico
South Carolina
South Dakota
Tennessee
Texas
Utah
Virginia
Washington
West Virginia
Wyoming
Undistributed
TotaT
Kaolin
W
212
113
31
7,519
1
W
W
W
W
W
555
W
W
1,144
9,575
Ball clay
W
W
W
514
W
270
784
Fire clay
81
W
3
251
W
W
89
W
51
474
Bentonite
W
35
147
W
211
320
16
19
W
W
2,496
187
3,432
Fuller's
earth
W
332
617
421
313
W
W
314
W
W
743
2,740
Common
clay and
shale
2,044
193
645
1,815
261
W
W
1,382
W
514
930
530
607
708
360
W
259
W
2,062
W
648
1,751
42
198
W
W
28
421
2,064
28
2,116
824
194
701
145
1,154
W
W
2,266
210
723
263
134
W
1,010
27,233
Totalb
22,124
3,830
8,048
27,463
1,964
W
39,150
949,737
W
38,877
3,516
2,226
2,828
2,942
3,646
W
1,141
W
8,770
W
34,382
11,059
11,332
909
3,204
W
W
74
2,417
9,015
W
11,016
4,178
1,086
2,890
335
25,663
W
44,573
13,247
1,028
3,248
2,633
322
81,573
124,996
1,505,423
W = withheld to avoid disclosing company proprietary data; included in totals and/or undistributed.
""Reference 1; units of Mg.
Data may not add to totals due to independent rounding.
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TABLE 2-2. END USES OF CLAY PRODUCED OR SOLD IN THE UNITED STATES
IN 1991s
Use
Absorbents
Ceramics and glass
Chemical
manufacturing
Civil engineering and
sealing
Drilling mud
Fillers, extenders, and
binders
Filtering, clarifying,
and decolorizing
Floor and wall tile
Heavy clay products
Lightweight aggregate
Pelletizing iron ore
Refractories
Other
Exports
Total
Kaolin
919
170
44
4,415
455
1,790
65
1,931
9,575
Ball
clay
302
12
135
168
17
51
90
784
Fire
clay
21
21
412
14
4
474
Bentonite
298
32
177
693
141
5
5
717
828
96
438
3,432
Fuller's
earth
2,419
15
32
369
20
26
27
129
2,740
Common
clay and
shale
242
84
80
429
22,587
3,599
98
197
7
27,233
Total
2,717
1,328
170
317
724
5,141
26
497
23,094
3,599
717
3,146
450
2,599
44,237
""Reference 1; all figures in units of thousands of Mg; data may not add to totals due to
independent rounding.
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60 percent of total domestic kaolin output. Most large kaolin producers have operations in Georgia,
which accounted for 79 percent of the kaolin production. The second leading kaolin producing State is
South Carolina, which accounted for 6 percent of total production in 1991. Most kaolin plants are
highly integrated operations that are capable of mining, processing, packaging, and shipping the
finished product. Major end uses of kaolin sold or used in the United States in 1991 were
paper-coating (34 percent), refractories (21 percent), paper-filling (14 percent), fiberglass and
insulation (5 percent), face brick (3 percent), rubber (3 percent), and paint and chemicals (3 percent).
2.1.2 Ball Clay
Ball clay is a plastic, white-firing clay used mainly for bonding in ceramic ware, primarily
dinnerware, floor and wall tile, pottery, and sanitary ware. The principal component of ball clay is
kaolinite, which constitutes at least 70 percent of the material. Organic matter is also common in most
ball clays, and ball clays usually are much finer grained than kaolins. The most important properties
of ball clays are high plasticity, high wet and dry strength, high shrinkage due to drying and firing,
and a wide vitrification range.
In 1991, six producers operated 36 mines in five States. Total domestic production of ball
clay in 1991 amounted to 784,000 Mg. Tennessee ball clay production accounted for approximately
66 percent of the total output. Other major producing States were Kentucky, Mississippi, Texas, and
Indiana. Major end uses of ball clay in 1991 were sanitary ware (20 percent); floor and wall tile
(20 percent); fillers, extenders, and binders (15 percent); and dinnerware (15 percent).
2.1.3 Fire Clay
Fire clays are composed primarily of kaolinite, but also may contain several other materials
including diaspore, burley, burley-flint, ball clay, and bauxitic clay and shale. Due to their ability to
withstand temperatures of 1500 °C (2700°F) or higher, fire clays generally are used for refractories or
to raise vitrification temperatures in heavy clay products. Fire clay producers generally are refractory
manufacturers that use the clays to produce firebrick and other refractory materials.
In 1991, 78 fire clay mines were operated by 19 firms in 7 States. Total domestic production
of fire clay sold in 1991 amounted to 474,000 Mg. The leading fire clay producing States, in
descending order of production, in 1991 were Missouri, Ohio, Alabama, New Jersey, Pennsylvania,
and New Mexico.
2.1.4 Bentonite
Bentonite is a clay composed primarily of smectite minerals, usually montmorillonite.
Bentonite can be classified as swelling or nonswelling, based on how much the material swells when
wet. The swelling type of bentonite has a high-sodium ion concentration, and its volume increases 15
to 20 times its dry volume when wetted with water. Nonswelling bentonites usually are high in
calcium and swell slightly more than common clay. The swelling types of bentonite are used largely
in drilling muds, in foundry sands, and in pelletizing taconite iron ores. The nonswelling types of
bentonite are used mostly in conjunction with the swelling bentonites in foundry sand mixes. In
addition, nonswelling bentonites are used in decolorizing and purifying mineral, vegetable, and animal
oils.
Firms producing bentonite operated 144 mines in 11 States. Wyoming was the leading State,
accounting for 73 percent of the total output. Total domestic production of bentonite in 1991
-------
amounted to 3,432,000 Mg. The swelling-type bentonite is produced mainly in Wyoming and
Montana, and the nonswelling-type bentonite is produced in Mississippi and Texas. The United States
is the world's largest producer and exporter of bentonite. Major end uses of bentonite in 1991 were
drilling mud (23 percent), foundry sand (25 percent), iron ore pelletizing (21 percent), absorbents
(9 percent), and waterproofing and sealing (6 percent).
2.1.5 Fuller's Earth
Fuller's earth is defined as a nonplastic clay or claylike material that typically is high in
magnesia and has specialized decolorizing and purifying properties. Fuller's earth and bentonite are
closely related, and much of the clay sold as fuller's earth is actually bentonite. The two major end
uses of fuller's earth are pet waste and oil and grease absorbents.
Domestic fuller's earth production totalled 2,740,000 Mg in 1991. Nineteen companies
produced fuller's earth from 37 mines in 10 States. Eleven of the mines were located in Florida and
Georgia. The United States is the world's largest producer and user of fuller's earth. Major end uses
of fuller's earth in 1991 were pet waste absorbents (65 percent), oil and grease absorbents
(13 percent), and pesticides and related products (7 percent).
2.1.6 Common Clay and Shale
Common clay is defined as a plastic clay or claylike material with a vitrification point below
1100°C. Shale is a laminated sedimentary rock that is formed by the consolidation of clay, mud, or
silt. Common clay and shale are composed mainly of illite or chlorite, but also may contain kaolin
and montmorillonite. Common clay and shale deposits are found throughout the United States and are
used primarily to manufacture structural clay products such as brick, drain tile, portland cement
clinker, and lightweight aggregate. Domestic clay and shale generally are mined and used onsite to
fabricate or manufacture products.
Common clay and shale were mined commercially in 44 States and Puerto Rico in 1991.
Total domestic production of common clay and shale amounted to 27,233,000 Mg in 1991 and
accounted for 62 percent of total domestic clay production. Domestic resources are almost unlimited,
but relatively few deposits are suitable for manufacturing lightweight aggregate. Major end uses of
common clay and shale in 1991 were brick (43 percent), portland and other cements (37 percent), and
lightweight aggregate (13 percent).
1-4
2.2 PROCESS DESCRIPTION
Most domestic clay is mined by open-pit methods using various types of equipment, including
draglines, power shovels, front-end loaders, backhoes, scraper-loaders, and shale planers. In addition,
some kaolin is extracted by hydraulic mining and dredging. Most underground clay mines are located
in Pennsylvania, Ohio, and West Virginia, where the clays are associated with coal deposits. A higher
percentage of fire clay is mined underground than the percentage of other clays mined underground
because the higher quality fire clay deposits are found at depths that make open-pit mining less
profitable.
Clays usually are transported by truck from the mine to the processing plants, many of which
are located at or near the mine. For most applications, clays are processed by mechanical methods,
such as crushing, grinding, and screening, that do not appreciably alter the chemical or mineralogical
-------
properties of the material. However, because clays are used in such a wide range of applications, it is
often necessary to use other mechanical and chemical processes, such as drying, calcining, bleaching,
blunging, and extruding to prepare the material for use.
Primary crushing reduces material size from as much as one meter to a few centimeters in
diameter and typically is accomplished using jaw or gyratory crushers. Rotating pan crushers, cone
crushers, smooth roll crushers, toothed roll crushers, and hammer mills are used for secondary
crushing, which further reduces particle size to 3 mm (0.1 in.) or less. For some applications, tertiary
size reduction is necessary and is accomplished by means of ball, rod, or pebble mills, which are often
combined with air separators. Screening typically is carried out by means of two or more multi-deck
sloping screens that are mechanically or electromagnetically vibrated. Pug mills are used for blunging,
and rotary, fluid bed, and vibrating grate dryers are used for drying clay materials. At most plants that
calcine clay, rotary or flash calciners are used. However, multiple hearth furnaces often are used to
calcine kaolin.
Material losses due to basic mechanical processing generally are insignificant. However,
material losses for processes such as washing and sizing can reach 30 to 40 percent. The most
significant processing losses occur in the processing of kaolin and fuller's earth.
The following paragraphs describe the steps used to process each of the six categories of clay.
Table 2-3 summarizes these processes by clay type.
2.2.1 Kaolin
Kaolin is both dry- and wet-processed. The dry process is simpler and produces a lower
quality product than is produced by the wet process. Dry-processed kaolin is used mainly in the
rubber industry, and to a lesser extent, for paper filling and to produce fiberglass and sanitary ware.
Wet-processed kaolin is used extensively in the paper manufacturing industry. A process flow
diagram for kaolin mining and dry processing is presented in Figure 2-1; Figure 2-2 illustrates the
process flow for the wet processing of kaolin.
In the dry process, the raw material is crushed to the desired size, dried in rotary dryers,
pulverized and air-floated to remove most of the coarse grit. Wet processing of kaolin begins with
blunging to produce a slurry, which then is fractionated into coarse and fine fractions using
centrifuges, hydrocyclones, or hydroseparators. At this step in the process, various chemical methods,
such as bleaching, and physical and magnetic methods may be used to refine the material. Chemical
processing includes leaching with sulfuric acid, followed by the addition of a strong reducing agent
such as hydrosulfite. Prior to drying, the slurry is filtered and dewatered by means of a filter press,
centrifuge, rotary vacuum filter, or tube filter. The filtered dewatered slurry material may be shipped
or further processed by drying in apron, rotary, or spray dryers. Following the drying step, the kaolin
may be calcined for use as filler or refractory material. Multiple hearth furnaces are most often used
to calcine kaolin. Flash and rotary calciners also are used.
2.2.2 Ball Clay
Mined ball clay, which typically has a moisture content of approximately 28 percent, first is
stored in drying sheds until the moisture content decreases to 20 to 24 percent. The clay then is
shredded in a disintegrator into small pieces 1.3 to 2.5 centimeters (cm) (0.5 to 1 in.) in thickness.
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TABLE 2-3. CLAY PROCESSING OPERATIONS
Process
Mining
Stockpiling
Crushing
Grinding
Screening
Mixing
Blunging
Air flotation
Slurrying
Extruding
Drying
Calcining
Packaging
Other
Kaolin
X
X
X
X
X
X
X
X
X
X
X
X
Water
fractionation,
magnetic
separation,
acid treatment,
bleaching
Ball clay
X
X
X
X
X
X
X
X
Shredding,
pulverizing
Fire clay
X
X
X
X
X
X
X
X
Weathering,
blending
Bentonite
X
X
X
X
X
X
Cation
exchange,
granulation,
air
classifying
Fuller's
earth
X
X
X
X
X
X
X
X
X
Dispersing
Common
clay and
shale
X
X
X
X
X
X
X
X
X
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CD
A
Rainwater
Ground Water
OPEN PIT MINING
SCO: 3-05-041-01
Truck x
RAW MATERIAL TRANSFER
SCC: 3-05-041-03
CD
A
CD
A
RAW MATERIAL
STORAGE
SCC: 3-05-041-02
RAW MATERIAL TRANSFER
SCC: 3-05-041-03
CD
A
CD
A
CRUSHING
SCC: 3-05-041-15
RAW MATERIAL TRANSFER
SCC: 3-05-041-03
CD
A
CD©
A A
DRYING
SCC: 3-05-041-30 to 33, 39
PRODUCT TRANSFER
SCC: 3-05-041-70
CD
A
CD
A
SCREENING/
CLASSIFICATION
SCC: 3-05-041-51
PRODUCT TRANSFER
SCC: 3-05-041-70
CD
A
PACKAGING
SCC: 3-05-041-72
PRODUCT SHIPPING
SETTLING PONDS
Effluent
-^Solid Waste
KEY
(T) PM emissions
(TlGaseous emissions
TO ONSITE
REFRACTORY
MANUFACTURING
Figure 2-1. Process flow diagram for kaolin mining and dry processing.
(SCC = Source Classification Code)
-------
©
A
Pit Pumpout
RAW MATERIAL
TRANSFER
SCC: 03-05-041-03
BLUNGING AND/OR
PUG MILLING
Water
©
A
KEY
rM PM Emissions
(f] Gaseous emissions
Optional process
DEGRITTINGAND
CLASSIFICATION
SCC: 03-05-041-29
RAW MATERIAL
TRANSFER
SCC: 03-05-041-03
©©
A A
©
A
BLEACHING
AND/OR CHEMICAL
TREATMENT
SCC: 03-05-041-60
70% Slurry Product
©
A
DRYING
SCC: 03-05-041-30 TO 33, 39
PRODUCT
TRANSFER
SCC: 03-05-041-70
PRODUCT ©
TRANSFER A
SCC: 03-05-041-70 ;
PRODUCT
STORAGE
SCC: 03-05-041-71
©@
A A
©
A
CALCINING
SCC: 03-05-041-40 TO 42, 49
PRODUCT
TRANSFER A
SCC: 03-05-041-70
PRODUCT
STORAGE
SCC: 03-05-041-71
PRODUCT ©
TRANSFER i
SCC: 03-05-041-70
>->
SHIPPING
PRODUCT ©
TRANSFER A
SCC: 03-05-041-70
SHIPPING
Figure 2-2. Process flow diagram for wet process kaolin for high grade products.
(SCC = Source Classification Code)
10
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The shredded material then is either dried or ground in a hammer mill. Material exiting the hammer
mill is mixed with water and bulk loaded as a slurry for shipping.
Indirect rotary or vibrating grate dryers are used to dry ball clay. Combustion gases from the
firebox pass through an air-to-air heat exchanger to heat the drying air to a temperature of
approximately 300°C (570°F). The clay is dried to a moisture content of 8 to 10 percent. Following
drying, the material is ground in a roller mill and shipped. The ground ball clay may also be mixed
with water and bulk loaded as a slurry for shipping. A flow diagram for ball clay processing is
presented in Figure 2-3.
2.2.3 Fire Clay
The processing of fire clay is depicted in Figure 2-4. Mined fire clay first is transported to the
processing plant and stockpiled. In some cases, the crude clay is weathered for 6 to 12 months,
depending on the type of fire clay. Freezing and thawing breaks the material up, resulting in smaller
particles and improved plasticity. The material then is crushed and ground. At this stage in the
process, the clay has a moisture content of 10 to 15 percent. For certain applications, the clay is dried
in mechanical dryers to reduce the moisture content of the material to 0 to 7 percent. Typically, rotary
and vibrating grate dryers fired with natural gas or fuel oil are used for drying fire clay.
To increase the refractoriness of the material, fire clay often is calcined. Calcining eliminates
moisture and organic material and causes a chemical reaction to occur between the alumina and silica
in the clay, rendering a material (mullite) that is harder, denser, and more easily crushed than
uncalcined fire clay. After the clay is dried and/or calcined, the material is crushed, ground, and
screened. After screening, the processed fire clay may be blended with other materials, such as
organic binders, prior to being formed in the desired shapes and fired.
2.2.4 Bentonite
A process flow diagram for bentonite processing is provided in Figure 2-5. Mined bentonite
first is transported to the processing plant and stockpiled. If the raw clay has a relatively high
moisture content (30 to 35 percent), the stockpiled material may be plowed to facilitate air drying to a
moisture content of 16 to 18 percent. Stockpiled bentonite may also be blended with other grades of
bentonite to produce a uniform material. The material then is passed through a grizzly and crusher to
reduce the clay pieces to less than 2.5 cm (1 in.) in size. Next, the crushed bentonite is dried in rotary
or fluid bed dryers fired with natural gas, oil, or coal to reduce the moisture content to 7 to 8 percent.
The temperatures in bentonite dryers generally range from 900°C (1650°F) at the inlet to 100° to
200°C (210° to 390°F) at the outlet. The dried material then is ground by means of roller or hammer
mills. At some facilities where specialized products are prepared, the bentonite material is passed
through an air classifier after being ground. Soda ash also may be added to the processed material to
improve the swelling properties of the bentonite.
2.2.5 Fuller's Earth
A flow diagram for fuller's earth processing is provided in Figure 2-6. After being mined,
fuller's earth is transported to the processing plant, crushed, ground, and stockpiled. Prior to drying,
fuller's earth is fed into secondary grinders to further to reduce the size of the material. At some
plants, the crushed material is fed into a pug mill, mixed with water, and extruded to improve the
properties needed for certain end products. The material then is dried in rotary or fluid bed dryers
11
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12
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13
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14
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(SCC = Source Classification Code)
15
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fired with natural gas or fuel oil. Drying reduces the moisture content to 0 to 10 percent from its
initial moisture content of 40 to 50 percent. The temperatures in fuller's earth dryers depend on the
end used of the product. For colloidal grades of fuller's earth, drying temperatures of approximately
150°C (300°F) are used; for absorbent grades, drying temperatures of 650°C (1200°F) are typical. In
some plants, fuller's earth is calcined rather than dried. In these cases, an operating temperature of
approximately 675°C (1250°F) is used. The dried or calcined material then is ground by means of
roller or hammer mills and screened.
2.2.6 Common Clay and Shale
A flow diagram for common clay and shale processing is provided in Figure 2-7. Common
clay and shale generally are mined, processed, formed, and fired at the same site to produce the final
end product. Processing generally begins with primary crushing and stockpiling. The material then is
ground and screened. Oversize material may be further ground to produce particles of the desired size.
For some applications, common clay and shale are dried to reduce the moisture content to desired
levels. Further processing may include blunging or mixing with water in a pug mill, extruding, and
firing in a kiln, depending on the type of end product.
2.3 EMISSIONS3
The primary pollutants of concern in clay processing operations are particulate matter (PM)
and PM less than 10 micrometers (PM-10). Particulate matter is emitted from all dry mechanical
processes, such as crushing, screening, grinding, and materials handling and transfer operations. The
emissions from dryers and calciners include products of combustion, such as carbon monoxide (CO),
carbon dioxide (CO2), nitrogen oxides (NOX), and sulfur oxides (SOX), in addition to filterable and
condensible PM. Volatile organic compounds associated with the raw materials and the fuel also may
be emitted from drying and calcining.
2.4 CONTROL TECHNOLOGY3
Cyclones, wet scrubbers, and fabric filters are the most commonly used devices to control PM
emissions from most clay processing operations. Cyclones often are used for product recovery from
mechanical processes. In such cases, the cyclones are not considered to be an air pollution control
device. Electrostatic precipitators also are used at some facilities to control PM emissions.
16
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REFERENCES FOR SECTION 2
1. S. H. Patterson and H. H. Murray, "Clays," Industrial Minerals and Rocks, Volume 1, Society of
Mining Engineers, New York, NY, 1983.
2. R. L. Virta, Annual Report 1991: Clays (Draft), Bureau of Mines, U.S. Department of the Interior,
Washington, D.C., September 1992.
3. Calciners and Dryers in Mineral Industries-Background Information for Proposed Standards,
EPA-450/3-85-025a, U. S. Environmental Protection Agency, Research Triangle Park, NC, October
1985.
4. J. T. Jones and M. F. Berard, Ceramics, Industrial Processing and Testing, Iowa State University
Press, Ames, IO, 1972.
18
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3. GENERAL DATA REVIEW AND ANALYSIS
3.1 LITERATURE SEARCH AND SCREENING
Data for this investigation were obtained from a number of sources within the Office of Air
Quality Planning and Standards (OAQPS) and from outside organizations. The docket for the
development of new source performance standards (NSPS) for calciners and dryers in the mineral
industries was reviewed for information on the industry, processes, and emissions. The Crosswalk/Air
Toxic Emission Factor Data Base Management System (XATEF) and VOC/PM Speciation Data Base
Management System (SPECIATE) data bases were searched by SCC for identification of the potential
pollutants emitted and emission factors for those pollutants. A general search of the Air CHIEF CD-
ROM also was conducted to supplement the information from these two data bases.
Information on the industry, including number of plants, plant location, and annual production
capacities, was obtained from the Minerals Yearbook and Census of Manufactures. The Aerometric
Information Retrieval System (AIRS) data base also was searched for data on the number of plants,
plant location, and estimated annual emissions of criteria pollutants.
A number of sources of information were investigated specifically for emission test reports and
data. A search of the Test Methods Storage and Retrieval (TSAR) data base was conducted to identify
test reports for sources within the sand and gravel processing industry. Copies of these test reports
were obtained from the files of the Emission Measurement Branch (EMB). The EPA library was
searched for additional test reports. A list of plants that have been tested within the past 5 years was
compiled from the AIRS data base. Using this information and information obtained on plant location
from the Minerals Yearbook and Census of Manufactures, State and Regional offices were contacted
about the availability of test reports. However, the information obtained from these offices was
limited. Publications lists from the Office of Research and Development (ORD) and Control
Technology Center (CTC) were also searched for reports on emissions from the sand and gravel
processing industry. In addition, representative trade associations were contacted for assistance in
obtaining information about the industry and emissions.
To reduce the amount of literature collected to a final group of references from which
emission factors could be developed, the following general criteria were used:
1. Emission data must be from a primary reference:
a. Source testing must be from a referenced study that does not reiterate information from
previous studies.
b. The document must constitute the original source of test data. For example, a technical
paper was not included if the original study was contained in the previous document. If the exact
source of the data could not be determined, the document was eliminated.
2. The referenced study must contain test results based on more than one test run.
3. The report must contain sufficient data to evaluate the testing procedures and source
operating conditions.
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A final set of reference materials was compiled after a thorough review of the pertinent
reports, documents, and information according to these criteria.
3.2 EMISSION DATA QUALITY RATING SYSTEM
As part of the analysis of the emission data, the quantity and quality of the information
contained in the final set of reference documents were evaluated. The following data were excluded
from consideration:
1. Test series averages reported in units that cannot be converted to the selected reporting
units;
2. Test series representing incompatible test methods (i.e., comparison of EPA Method 5 front
half with EPA Method 5 front and back half);
3. Test series of controlled emissions for which the control device is not specified;
4. Test series in which the source process is not clearly identified and described; and
5. Test series in which it is not clear whether the emissions were measured before or after the
control device.
Test data sets that were not excluded were assigned a quality rating. The rating system used
was that specified by EIB for preparing AP-42 sections. The data were rated as follows:
A—Multiple tests that were performed on the same source using sound methodology and
reported in enough detail for adequate validation. These tests do not necessarily conform to the
methodology specified in EPA reference test methods, although these methods were used as a guide
for the methodology actually used.
B~Tests that were performed by a generally sound methodology but lack enough detail for
adequate validation.
C~Tests that were based on an untested or new methodology or that lacked a significant
amount of background data.
D~Tests that were based on a generally unacceptable method but may provide an order-of-
magnitude value for the source.
The following criteria were used to evaluate source test reports for sound methodology and
adequate detail:
1. Source operation. The manner in which the source was operated is well documented in the
report. The source was operating within typical parameters during the test.
2. Sampling procedures. The sampling procedures conformed to a generally acceptable
methodology. If actual procedures deviated from accepted methods, the deviations are well
documented. When this occurred, an evaluation was made of the extent to which such alternative
procedures could influence the test results.
20
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3. Sampling and process data. Adequate sampling and process data are documented in the
report, and any variations in the sampling and process operation are noted. If a large spread between
test results cannot be explained by information contained in the test report, the data are suspect and
were given a lower rating.
4. Analysis and calculations. The test reports contain original raw data sheets. The
nomenclature and equations used were compared to those (if any) specified by EPA to establish
equivalency. The depth of review of the calculations was dictated by the reviewer's confidence in the
ability and conscientiousness of the tester, which in turn was based on factors such as consistency of
results and completeness of other areas of the test report.
3.3 EMISSION FACTOR QUALITY RATING SYSTEM
The quality of the emission factors developed from analysis of the test data was rated utilizing
the following general criteria:
A—Excellent: Developed only from A-rated test data from many randomly chosen facilities in
the industry population. The source category is specific enough so that variability within the source
category population may be minimized.
B—Above average: Developed only from A-rated test data from a reasonable number of
facilities. Although no specific bias is evident, it is not clear if the facilities tested represent a random
sample of the industry. The source category is specific enough so that variability within the source
category population may be minimized.
C—Average: Developed only from A- and B-rated test data from a reasonable number of
facilities. Although no specific bias is evident, it is not clear if the facilities tested represent a random
sample of the industry. In addition, the source category is specific enough so that variability within
the source category population may be minimized.
D—Below average: The emission factor was developed only from A- and B-rated test data
from a small number of facilities, and there is reason to suspect that these facilities do not represent a
random sample of the industry. There also may be evidence of variability within the source category
population. Limitations on the use of the emission factor are noted in the emission factor table.
E—Poor: The emission factor was developed from C- and D-rated test data, and there is
reason to suspect that the facilities tested do not represent a random sample of the industry. There
also may be evidence of variability within the source category population. Limitations on the use of
these factors are always noted.
The use of these criteria is somewhat subjective and depends to an extent on the individual
reviewer. Details of the rating of each candidate emission factor are provided in Section 4 of this
report.
REFERENCES FOR SECTION 3
1. Technical Procedures for Developing AP-42 Emission Factors and Preparing AP-42 Sections,
EPA-454/B-93-050. Office of Air Quality Planning and Standards, U. S. Environmental Protection
Agency, Research Triangle Park, NC, October 1993.
21
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4. AP-42 SECTION DEVELOPMENT
This section describes the test data and methodology used to develop emission factors for
AP-42 Section 8.32, Clay Processing. First, each of the emission test reports and other documents
with emission data found during the literature search is described. Following the description of the
test reports, the results of the data analysis are discussed.
4.1 REVIEW OF SPECIFIC DATA SETS
A total of 10 references were reviewed in the process of developing the draft AP-42 section on
clay processing. For kaolin processing, one summary document and four test reports documenting
emission tests at kaolin processing plants were reviewed. Data from the emission tests documented in
References 1, 2, and 4 were used for emission factor development. The emission test presented in
Reference 3 provided an evaluation of visible emissions only and could not be used for emission
factor development. Reference 7, which is the background information document for the NSPS for
calciners and dryers, contains summary data from emission tests at four kaolin processing plants,
including summaries of the emission tests documented in References 1 and 3. The four tests
summarize results from tests at four different plants (Plants Jl, J2, J3, and J4). Data from the two
tests (Plants J2 and J4) that are not documented in References 1 and 3 are discussed in Section 4.2.1,
Review of Specific Data Sets.
For ball clay processing, data from one emission test (summarized in Reference 7) were used
for emission factor development. For fire clay processing, data from three emission tests (Referenes 8,
9, and 10) were used to develop emission factors. For bentonite and fuller's earth processing,
Reference 7 contains summary data for emission tests conducted at two bentonite and one fuller's
earth processing facilities. In addition, two emission test reports (References 5 and 6) from a fuller's
earth processing facility were used for developing emission factors.
4.1.1 Reference 1
This reference documents an emission test conducted at the American Industrial Clay
Company in Sandersville, Georgia in September, 1974. Filterable particulate matter (PM) and carbon
dioxide (CO2) emissions were measured at the outlet of a fabric filter controlling emissions from a
kaolin spray dryer. Filterable PM emissions were quantified using EPA Method 5 (three test runs),
and CO2 emissions were determined by Orsat analysis. The dryer operated at 83 percent of design
capacity during the tests. Production rates were calculated using the slurry feed rates shown in the
report in conjunction with the estimated slurry and finished product moisture contents. The slurry was
approximately 60 percent kaolin and 40 percent water, and the finished product contained less than
one percent moisture.
The data from this report were assigned a B rating. The testing methodology was sound,
adequate detail was provided, and no problems were reported during the valid test runs. However, the
production rates may be slightly in error because the material moisture contents were estimated.
4.1.2 Reference 2
This reference documents an emission test conducted at the American Industrial Clay
Company in Sandersville, Georgia, in August and September 1974. Uncontrolled filterable PM and
CO2 emissions were measured at the outlet of three exhaust stacks from a kaolin apron dryer.
22
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Filterable PM emissions were quantified using EPA Method 5, and CO2 emissions were measured by
Orsat analysis. Three test runs were performed on each stack. Production rates were calculated using
the slurry feed rates shown in the report in conjunction with the estimated slurry and finished product
moisture contents. The slurry was approximately 60 percent kaolin and 40 percent water, and the
finished product contained about 6 percent water.
The data from this report were assigned a B rating. The testing methodology was sound,
adequate detail was provided, and no problems were reported during the valid test runs. However, the
production rates may be slightly in error because the material moisture contents were estimated.
4.1.3 Reference 3
This reference documents an emission test conducted at Thiele Kaolin in Sandersonville,
Georgia, on December 6 and 7, 1978. The test program included only a visible emission evaluation,
and the report includes no data suitable for inclusion in AP-42.
4.1.4 Reference 4
This reference documents an emission test conducted at a kaolin processing plant in 1983.
The sources tested include the inlet and outlet of a venturi scrubber controlling emissions from a
multiple hearth furnace, the inlet and outlet of a fabric filter controlling emissions from a kaolin
cooling/product recovery system, and the inlet and outlet of a fabric filter controlling emissions from a
flash calciner. Pollutants measured include filterable PM and CO2, and particle size analyses were
performed at the inlet and outlet of each fabric filter. Process rates were not available for the test
conducted on the kaolin cooling/product recovery system.
Method 5 was used to measure PM emissions, particle size distribution was quantified using
cascade impactors with preseparators, and Orsat was used to measure CO2 concentrations in the
exhaust streams. Three runs were conducted at each source sampled. The data for the first run on the
flash calciner fabric filter outlet was voided due to bag slippage; no other problems were reported.
Emission factors were developed for filterable PM, filterable PM-10, and CO2 emissions from the
furnace and flash calciner.
With the exception of the results of the test on the flash calciner fabric filter outlet, the test
data are rated A. The methodologies were sound, the results are fully documented, and no problems
were reported. The flash calciner fabric filter outlet results were downrated from A to B because only
two test runs were valid.
4.1.5 Reference 5
This reference documents an industry sponsored emission test conducted at a fuller's earth
processing plant. The test was conducted in February 1979. Filterable PM and CO2 emissions were
measured at the outlet of a wet scrubber operating at a pressure drop of 3.7 kilopascals (kPa)
(15 inches of water column [in. w.c.]) controlling emissions from several sources, including two
screenhouses, a rotary dryer, a rotary cooler, a grinder, and a warehouse in which product is packaged
for shipment. The dryer dries material with a moisture content of 10 to 15 percent to a moisture
content of approximately 1 percent. A multicyclone (for PM removal) was located prior to the
scrubber. Filterable PM emissions were quantified using EPA Method 5 (three test runs), and CO2
23
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emissions were measured by Orsat analysis. However, CO2 was not detected during any of the test
runs.
The data from this report were assigned an A rating. The testing methodology was sound,
adequate detail was provided, and no problems were reported during the valid test runs.
4.1.6 Reference 6
This reference documents an industry sponsored emission test conducted at the same fuller's
earth processing plant for which emission data were documented in Reference 5. The test was
conducted in September 1978. Filterable PM and CO2 emissions were measured at the outlet of a wet
scrubber operating at a pressure drop of 3.7 kPa (15 in. w.c.) controlling emissions from a rotary
dryer, a rotary cooler, and a warehouse in which product is packaged for shipment. The dryer dries
material from an initial moisture content of approximately 50 percent to a moisture content of 10 to
15 percent. A multicyclone was located prior to the scrubber. Filterable PM emissions were
quantified using EPA Method 5 (3 test runs), and CO2 emissions were measured by Orsat analysis.
The data from this report were assigned an A rating. The testing methodology was sound,
adequate detail was provided, and no problems were reported during the valid test runs.
4.1.7 Reference 7
This reference includes descriptions and summaries of results of emission tests conducted at
four kaolin processing plants (Plants Jl, J2, J3, and J4), one ball clay processing plant (Plant Bl),
three fire clay processing plants (Plants Fl, F2, and F3) and two bentonite processing plants (Plants Cl
and C3). An additional test conducted at a fuller's earth processing plant (Plant Gl) also is described
in the reference. However, because process rates for that test are confidential, emission factors could
not be developed.
The emission tests conducted at kaolin processing Plants Jl and J3 are the same tests
documented in References 4 and 1, respectively. The emission tests conducted on fire clay processing
sources at Plants Fl, F2, and F3 are the same tests as those documented in References 8, 10, and 9,
respectively. The emission tests conducted at Plants J2, J4, Bl, Cl, and C3 are described below.
The industry-sponsored test at Plant J2 included filterable PM measurements at the outlet of a
shaker fabric filter controlling emissions from a spray dryer and at the outlet of a venturi scrubber
(pressure drop of 4.5 to 5.3 kPa [18 to 21 in. w.c.]) controlling emissions from a multiple hearth
furnace. Both the spray dryer and the furnace were fired by natural gas, and the raw material
processed was kaolin. However, because process rates for this test are confidential, emission factors
could not be developed from the data.
The industry-sponsored test at Plant J4 included filterable PM measurements at the outlet of a
shaker fabric filter controlling emissions from a natural gas-fired spray dryer. The dryer operated at
104 percent of maximum capacity during the tests. The raw material processed was kaolin.
The industry-sponsored test at Plant B1 included filterable PM measurements at the outlet of a
pulse-jet fabric filter controlling emissions from a vibrating-grate dryer. The raw material processed
was a mixture of two types of ball clay.
24
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The EPA-sponsored test at Plant Cl included simultaneous filterable PM and particle size tests
performed on a coal-fired rotary dryer that was processing bentonite. Uncontrolled emissions were
measured at the cyclone inlet, and controlled emissions were measured at the outlet of the fabric filter.
The particle size analysis indicated that approximately 7 percent of the uncontrolled filterable PM was
PM-10, and about 74 percent of the filterable PM measured at the fabric filter outlet was PM-10.
The industry-sponsored test at Plant C3 included filterable PM measurements at the outlet of a
electrostatic precipitator (ESP) controlling emissions from a rotary dryer processing bentonite. Four
test runs were performed because the degree of isokinetic variation during Run 1 did not conform with
EPA requirements. Data from Run 1 were not used for emission factor development.
The data from the all of the emission tests except for Plant C3 were assigned a B rating. The
test methodologies are assumed to be sound, adequate detail was provided, and no problems were
reported during the valid test runs. The data were downrated to B because the reference is a
secondary source of data, and the original test reports were not available for review. The data from
the test at Plant C3 were assigned a C rating because only 2 valid test runs were performed.
4.1.8 Reference 8
This test report included measurements of filterable PM, particle size distribution, and carbon
dioxide (CO2) on a rotary dryer and was sponsored by EPA as part of the emission test program for
the development of the proposed NSPS for calciners and dryers. Emission rates were measured for
two types of fire clay used in refractory manufacturing—flint clay and plastic clay. A Method 5
sampling train was used for measuring the PM, and cascade impactors were used for quantifying the
particle size distribution. The CO2 emissions were measured using Method 3A (instrument analyzer).
Emissions from the dryer were controlled by means of a cyclone (for product recovery)
followed by a wet scrubber in series. The wet scrubber operated with a pressure drop of 2.7 to
3.2 kilopascals (kPa) (11 to 13 inches of water [in. w.c.]). Three runs were conducted on each of the
two clays. Uncontrolled emissions and controlled emissions, at both the cyclone and scrubber outlets,
were measured. In addition, a trace element analysis of the PM catch was performed for each of the
two clays. Analysis of the plastic clay and flint clay samples identified aluminum, beryllium, calcium,
chromium, iron, lead, mercury, magnesium, manganese, nickel, titanium, vanadium, and zinc.
A rating of A was assigned to both sets of PM, particle size distribution, and CO2 data. The
reports included adequate detail, the methodology appeared to be sound, and no problems were
reported. The trace element data were not rated due to the fact that only one run was analyzed.
4.1.9 Reference 9
This test included measurements of filterable PM, particle size distribution, sulfur dioxide
(SO2), and NOX on a coal-fired rotary calciner and was sponsored by EPA as part of the emission test
program for the development of the proposed NSPS for calciners and dryers. A Method 5 sampling
train was used for measuring the PM, and cascade impactors were used for quantifying the particle
size distribution. Sulfur dioxide and NOX emissions were measured in accordance with EPA Reference
Methods 6 and 7, respectively.
Emissions from the calciner were controlled by means of a multiclone (for product recovery)
followed by a venturi scrubber in series. The scrubber operated at a pressure drop of 4.5 kPa
25
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(18 in. w.c.). Three runs were conducted. For PM and particle size distribution, uncontrolled
emissions and controlled emissions at both the cyclone and scrubber outlets were measured. Sulfur
dioxide and NOX emissions were measured at the scrubber outlet only. In addition, a trace element
analysis of the PM catch for one run was performed. The analysis indicated trace amounts of
aluminum, beryllium, calcium, chromium, iron, lead, mercury, magnesium, manganese, nickel,
titanium, vanadium, and zinc.
A rating of A was assigned to the PM, particle size, SO2, and NOX test data. The reports
included adequate detail, the methodology appeared to be sound, and no problems were reported. The
trace element data were not rated due to the fact that only one run was analyzed.
4.1.10 Reference 10
This test included measurements of filterable PM and particle size distribution on a rotary
calciner and was sponsored by EPA as part of the emission test program for the development of the
proposed NSPS for calciners and dryers. A Method 5 sampling train was used for measuring the PM,
and cascade impactors were used for quantifying the particle size distribution.
Emissions from the calciner were controlled by means of a multiclone (for product recovery)
followed by a venturi scrubber in series. The scrubber operated at a pressure loss of 6 to 6.7 kPa
(24 to 27 in. w.c.). A total of three runs were conducted. For PM and particle size distribution,
uncontrolled emissions at the calciner outlet and controlled emissions at the scrubber outlet were
measured. In addition, a trace element analysis of the PM catch was performed. The analysis
identified calcium, chromium, iron, nickel, silicon, zinc, aluminum, magnesium, lead, mercury, and
fluorine in the sample. However, because the run number for the trace element analysis was not
identified in the report, it was not possible to develop emission factors from the data.
A rating of A was assigned to the PM and particle size test data. The reports included
adequate detail. Although some changes were made in the number of sampling points and sampling
time after the first run, the methodology appeared to be sound, and no problems were reported.
4.1.11 Review of XATEF and SPECIATE Data Base Emission Factors
The XATEF and SPECIATE data bases were searched for emission factors relevant to the clay
processing industry. No pertinent information was found.
4.1.12 Results of Data Analysis
Data were available for developing emission factors for several clay processing sources. These
emission data are summarized in Tables 4-1 to 4-12. The majority of these data sets are rated A or B.
The following paragraphs describe the results of the data analysis for each type of clay for which
emission factors could be developed.
4.1.12.1. Kaolin. Table 4-1 summarizes the emission data for kaolin processing, and particle
size data for kaolin processing are summarized in Table 4-2. All data sets presented in the tables are
rated either A or B. Emission factors were developed for emissions of filterable PM and CO2 from
spray dryers and apron dryers, and for emissions of filterable PM, filterable PM-10, and CO2 from
multiple hearth furnaces and flash calciners. The filterable PM-10 emission factors are based on the
filterable PM emission factors and the particle size data.
26
-------
TABLE 4-1. SUMMARY OF EMISSION DATA FOR KAOLIN PROCESSING3
(Factors represent uncontrolled emissions unless noted)
Source
Spray dryer with
fabric filter
Spray dryer with
fabric filter
Apron dryer
Apron dryer
Multiple hearth
furnace
Multiple hearth
furnace
Multiple hearth
furnace
Multiple hearth
furnace with venturi
scrubber
Flash calciner
Flash calciner
Flash calciner
Flash calciner with
fabric filter
Flash calciner with
fabric filter
Spray dryer with
fabric filter
Pollutant
Filterable PM
CO2
Filterable PM
CO2
Filterable PM
Filterable PM-10b
C02
Filterable PM
Filterable PM
Filterable PM-10C
C02
Filterable PM
Filterable PM-10d
Filterable PM
No. of
runs
3
3
3
3
3
3
6
3
3
3
3
2
2
3
Data
rating
B
B
B
B
A
A
A
A
A
A
A
B
B
B
Emission factor, kg/Mg (Ib/ton)
Minimum
0.15
(0.29)
75
(150)
0.58
(1.2)
36
(71)
15
(30)
7.1
(14)
120
(240)
0.091
(0.18)
500
(1,000)
170
(330)
230
(450)
0.026
(0.052)
0.023
(0.046)
0.013
(0.026)
Maximum
0.38
(0.75)
87
(173)
0.69
(1.4)
200
(400)
20
(39)
10
(21)
170
(350)
0.14
(0.28)
630
(1,200)
410
(820)
300
(600)
0.029
(0.058)
0.023
(0.046)
0.024
(0.047)
Average
0.29
(0.58)
81
(161)
0.62
(1.2)
140 (280)
17
(34)
8.2
(16)
140
(280)
0.12
(0.23)
550
(1,100)
280
(560)
260
(510)
0.028
(0.055)
0.023
(0.046)
0.018
(0.037)
Ref.
No.
1
1
2
2
4
4
4
4
4
4
4
4
4
T
Emission factor in kg/Mg (Ib/ton) of product.
bBased on filterable PM emission factor and three runs of particle size distribution measurements, which
indicated an average of 47 percent PM-10.
°Based on filterable PM emission factor and three runs of particle size distribution measurements, which
indicated an average of 51 percent PM-10.
dBased on filterable PM emission factor and three runs of particle size distribution measurements, which
indicated an average of 88 percent PM-10.
ePlant J4.
27
-------
TABLE 4-2. SUMMARY OF PARTICLE SIZE DATA FOR KAOLIN PROCESSING3
Particle size, (am
1.0
1.25
2.5
6.0
10
15
20
Cumulative percent less than size
Multiple hearth
furnace, uncontrolled
5.65
8.21
22.99
42.1
47.22
52.02
56.61
Flash calciner
Uncontrolled
11.14
25.32
44.65
50.87
55.35
59.45
With fabric filter
26.93
31.88
55.29
77.34
88.31
94.77
96.56
Reference 4.
TABLE 4-3. SUMMARY OF EMISSION DATA FOR BALL CLAY PROCESSING3
Source
Vibrating grate dryer
with fabric filter
Pollutant
Filterable
PM
No. of
runs
3
Data
rating
B
Emission factor, kg/Mg (Ib/ton)
Minimum
0.026
(0.051)
Maximum
0.11
(0.22)
Average
0.071
(0.14)
Ref
No.
7b
3Emission factor in kg/Mg (Ib/ton) of product.
bPlantBl.
28
-------
4.1.12.2. Ball clay. For ball clay, a single data set for fabric filter-controlled filterable PM
emissions from a vibrating grate dryer was available. The data are rated B and are summarized in
Table 4-3.
4.1.12.3. Fire clay. For rotary dryers, data were available for filterable PM and CO2
emissions for two types of fire clay (flint clay and plastic clay). These data are rated A and are
summarized in Table 4-4. Table 4-5 summarizes the trace element emission data for rotary dryers
processing fire clay. Because these data are based on a single test run, they are not rated and were not
used to develop emission factors for the AP-42 section. Table 4-6 summarizes the particle size
distribution data for rotary dryers drying fire clay. These data are assigned a rating of A.
For rotary calciners processing fire clay, data were available for filterable PM, CO2, SO2, and
NOX emissions. These data are rated A and are summarized in Table 4-7. Table 4-8 summarizes trace
element emission data for rotary calciners processing fire clay. Because these data are based on a
single test run, they are not rated and were not used to develop emission factors for the AP-42 section.
Table 4-9 summarizes the particle size distribution data for rotary calciners processing fire clay. These
data are assigned a rating of A.
4.1.12.4. Bentonite. Table 4-10 summarizes the emission data for bentonite processing
sources. Data were available for developing emission factors for filterable PM and filterable PM-10
emissions from rotary dryers drying bentonite. With one exception, these data are rated B; the
emission data for filterable PM emissions from an ESP-controlled rotary dryer were rated C for the
reason described previously. Table 4-11 summarizes the particle size data for bentonite rotary dryer
emissions. These data also are rated B.
4.1.12.5. Fuller's earth. The emission data for fuller's earth processing are presented in
Table 4-12. Emission data were available for filterable PM and CO2 emissions from a combination of
rotary dryer, rotary cooler, and packaging warehouse, and for filterable PM emissions from the
combined exhaust streams of a rotary dryer, rotary cooler, grinding and screening operation, and a
packaging warehouse. These data are rated A.
4.1.13 Summary of Average Emission Factors
Based on the data presented in Tables 4-1 to 4-12, average emission factors for clay
processing were developed; these average emission factors are summarized in Table 4-13. It should be
noted that the average emission factors presented for filterable PM-10 are based on the emission
factors for filterable PM and the particle size data. In addition, all emission factors for CO2 are
presented in Table 4-13 as uncontrolled emission factors. Although the CO2 factors are based largely
on emissions measured downstream of control devices, the control devices generally are expected to
have negligible effects on CO2 emissions, and the data did not indicate that the control devices were
reducing CO2 emissions.
In general, the average emission factors were based on no more than three A- or B-rated tests.
In view of the relative number of plants and the fact that the tests reviewed are not likely to represent
a random sample of the industry, these average emission factors were assigned a rating of D. The
emission factors based on C-rated data are assigned a rating of E.
29
-------
TABLE 4-4. SUMMARY OF EMISSION DATA FOR FIRE CLAY ROTARY DRYERS3
Type of control
None
None
Cyclone
Cyclone
Cyclone/scrubber
Cyclone/scrubber
None
None
Cyclone
Cyclone
Cyclone/scrubber
Cyclone/scrubber
Pollutant
Filterable PM
Filterable PM
Filterable PM
Filterable PM
Filterable PM
Filterable PM
CO2
CO2
CO2
CO2
CO2
CO2
No. of test
runs
3
3
3
3
3
3
3
3
3
3
3
3
Data
rating
A
A
A
A
A
A
A
A
A
A
A
A
Emission factor
Range,
kg/Mg (Ib/ton)
17-53
(34-110)
29-38
(58-77)
2.7-13
(5.4-25)
2.8-6.9
(5.7-14)
0.034-0.10
(0.067-0.21)
0.024-0.064
(0.048-0.13)
11-18
(21-36)
7.1-13
(14-25)
15-26
(30-52)
11-17
(22-34)
13-33
(26-67)
12-17
(23-35)
Average,
kg/Mg (Ib/ton)
32
(63)
34
(67)
6.0
(12)
5.1
(10)
0.062
(0.12)
0.043
(0.085)
13
(26)
9.7
(19)
19
(37)
14
(28)
20
(40)
14
(29)
Type of
clay
Flint
Plastic
Flint
Plastic
Flint
Plastic
Flint
Plastic
Flint
Plastic
Flint
Plastic
aReference 8. Emission factors in units kilograms of pollutant emitted per megagram of material processed
(kg/Mg) (pounds of pollutant emitted per ton of material processed [Ib/ton]).
30
-------
TABLE 4-5. SUMMARY OF TRACE ELEMENT EMISSION DATA FOR
FIRE CLAY ROTARY DRYERS3
Flint clay
Pollutant
Aluminum
Beryllium
Calcium
Chromium
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Titanium
Vanadium
Zinc
Uncontrolled
Emission factor
kg/Mg
1.1
1.2xl(r5
0.011
0.0031
0.12
0.00056
0.020
0.00087
e.oxio-6
0.0063
0.0015
0.0011
0.0058
Ib/ton
2.2
2.3xlO'5
0.022
0.0063
0.24
0.0011
0.040
0.0017
1.2xlO-5
0.013
0.0030
0.0023
0.012
Cyclone
Emission factor
kg/Mg
0.14
b
0.0018
0.00023
0.018
0.00010
0.0024
b
2.2xlO-6
0.00013
0.00044
0.00017
0.00012
Ib/ton
0.27
b
0.0036
0.00046
0.037
0.00020
0.0048
b
4.4xlO-6
0.00027
0.00088
0.00034
0.00025
Cyclone/scrubber
Emission factor
kg/Mg
0.0044
b
0.00070
1.4xlO-5
0.00068
7.4xlO'6
0.00016
5.2xlO-6
6.5xlO-7
9.1xlO'6
0.00011
9.1xlO-6
2.5xlO-5
Ib/ton
0.0088
b
0.0014
2.9xlO-5
0.0014
l.SxlO'5
0.00033
l.OxlO'5
1.3xlO-6
l.SxlO'5
0.00021
l.SxlO'5
4.9xlO-5
Plastic clay
Pollutant
Aluminum
Beryllium
Calcium
Chromium
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Titanium
Vanadium
Zinc
Uncontrolled
Emission factor
kg/Mg
2.4
8.2xlO-5
0.072
0.0055
0.19
0.00092
0.0084
b
2.0xlO'5
0.0029
0.0025
0.0036
0.0021
Ib/ton
4.7
0.00016
0.14
0.011
0.39
0.0018
0.017
b
4.0xlO'5
0.0057
0.0051
0.0073
0.0042
Cyclone
Emission factor
kg/Mg
0.40
l.lxlO'5
0.011
0.00098
0.029
0.00015
0.0077
b
4.5xlO'6
0.00073
0.00060
0.00063
0.00026
Ib/ton
0.79
2.2xlO'5
0.023
0.0020
0.058
0.00031
0.015
b
9.0x1 0'6
0.0015
0.0012
0.0013
0.00052
Cyclone/scrubber
Emission factor
kg/Mg
0.0037
b
0.0014
9.7xlO'6
0.00039
5.8xlO-6
0.00045
3.2xlO'6
6.4xlO'7
l.lxlO'5
5.9-xlO'5
5.6xlO'6
3.0xlO'5
Ib/ton
0.0075
b
0.0028
1.9xlO'5
0.00078
1.2xlO-5
0.00090
6.4xlO'6
1.3-xlO'6
2.3xlO-5
0.00012
l.lxlO'5
6.1xlO'5
31
-------
TABLE 4-5. (continued)
Average of results of plastic and flint clays
Pollutant
Aluminum
Beryllium
Calcium
Chromium
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Titanium
Vanadium
Zinc
Uncontrolled
Emission factor
kg/Mg
1.7
4.7xlO'5
0.041
0.0043
0.16
0.00074
0.014
0.00087
1.3xlO'5
0.0046
0.0020
0.0024
0.0039
Ib/ton
3.5
9.3xlO'5
0.083
0.0087
0.32
0.0015
0.028
0.0017
2.6xlO'5
0.0092
0.0040
0.0048
0.0079
Cyclone
Emission factor
kg/Mg
0.27
l.lxlO'5
0.0066
0.00061
0.024
0.00013
0.0051
b
3.4xlO'6
0.00043
0.00052
0.00040
0.00019
Ib/ton
0.53
2.2xlO'5
0.013
0.0012
0.047
0.00025
0.010
b
6.7X10'6
0.00087
0.0010
0.00080
0.00038
Cyclone/scrubber
Emission factor
kg/Mg
0.0041
b
0.0011
1.2xlO'5
0.00053
6.6X10'6
0.00031
4.2X10'6
6.5xlO'7
l.OxlO'5
8.3xlO'5
7.4X10'6
2.8xlO'5
Ib/ton
0.0081
b
0.0021
2.4xlO'5
0.0011
1.3xlO'5
0.00061
8.2X10'6
l.SxlO'6
2.0xlO'5
0.00017
1.5xlO'5
5.5xlO'5
""Reference 8. Based on 1 run; data are not rated. Emission factors in units kilograms of pollutant emitted
for megagram of material processed (kg/Mg) (pounds of pollutant emitted per ton of material processed
[Ib/ton]).
bBelow detection limit.
32
-------
TABLE 4-6. SUMMARY OF PARTICLE SIZE DATA FOR
FIRE CLAY ROTARY DRYERS
Flint clay
Diameter, micrometers
2.5
6.0
10.0
15.0
20.0
Uncontrolled
Cumulative % less than
diameter
3
14
36
50
66
Controlled (cyclone)
Cumulative % less than
diameter
13
32
53
71
78
Plastic clay
Diameter, micrometers
2.5
6.0
10.0
15.0
20.0
Uncontrolled
Cumulative % less than
diameter
2
6
12
24
36
Controlled (cyclone)
Cumulative % less than
diameter
14
29
38
48
57
Average
Diameter, micrometers
2.5
6.0
10.0
15.0
20.0
Uncontrolled
Cumulative % less than
diameter
3
10
24
37
51
Controlled (cyclone)
Cumulative % less than
diameter
14
31
46
60
68
""Reference 8. Data rated A.
33
-------
TABLE 4-7. SUMMARY OF TEST DATA FOR FIRE CLAY ROTARY CALCINERS
Type of
control
None
None
Multiclone
Multiclone/
scrubber
Multiclone/
scrubber
None
None
Multiclone
Multiclone/
scrubber
Multiclone/
scrubber
Multiclone/
scrubber
Multiclone/
scrubber
Pollutant
Filterable PM
Filterable PM
Filterable PM
Filterable PM
Filterable PM
C02
C02
C02
C02
C02
S02
NOX
No. of
test runs
3
3
3
3
3
3
3
3
3
3
3
3
Data
rating
A
A
A
A
A
A
A
A
A
A
A
A
Emission factor
Range,
kg/Mg (Ib/ton)
60-73
(120-145)
49-65
(99-130)
30-32
(60-63)
0.25-0.27
(0.49-0.54)
0.032-0.070
(0.064-0.14)
360-410
(710-810)
290-310
(570-620)
330-360
(660-720)
270-280
(530-560)
210-230
(420-460)
3.7-3.9
(7.4-7.8)
0.75-0.96
(1.5-1.9)
Average,
kg/Mg
(Ib/ton)
66
(130)
57
(110)
31
(61)
0.26
(0.51)
0.045
(0.090)
380
(760)
300
(600)
340
(680)
270
(550)
220
(440)
o o
3.8
(7.6)
0.87
(1.7)
Ref. No.
9
10
9
9
10
9
10
9
9
10
9
9
34
-------
TABLE 4-8. SUMMARY OF TRACE ELEMENT DATA FOR FIRE CLAY ROTARY
CALCINERS3
Pollutant
Aluminum
Beryllium
Calcium
Chromium
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Titanium
Vanadium
Zinc
Uncontrolled
Emission factor
kg/Mg
3.4
S.OxlO'5
0.080
0.0070
0.31
0.0019
0.024
0.00072
0.00014
0.0049
0.041
0.0049
0.020
Ib/ton
6.9
0.00016
0.16
0.014
0.62
0.0038
0.049
0.0014
0.00028
0.0098
0.081
0.0099
0.039
Multiclone
Emission factor
kg/Mg
1.2
S.OxlO'5
0.055
0.0018
0.19
0.0012
0.021
0.00032
5.1xlO'5
0.0018
0.025
0.0032
0.0017
Ib/ton
2.4
0.00016
0.11
0.0037
0.37
0.0025
0.041
0.00064
0.00010
0.0036
0.050
0.0065
0.0034
Multiclone/scrubber
Emission factor
kg/Mg
0.011
b
0.0027
2.6xlO'5
0.0011
3.6xlO'5
0.00028
b
3.9X10'6
3.6xlO'5
0.00035
7.2xlO'5
8.7xlO'5
Ib/ton
0.021
b
0.0054
5.2xlO'5
0.0023
7.1xlO'5
0.00057
b
7.8xlO'6
7.2xlO'5
0.00070
0.00014
0.00017
""Reference 9; based on 1 run; data are not rated.
bBelow detection limit.
35
-------
TABLE 4-9. SUMMARY OF PARTICLE SIZE DATA FOR FIRE
CLAY ROTARY CALCINERS
Reference 9
Reference 10
Diameter,
micrometers
1.0
1.25
2.5
6.0
10.0
15.0
20.0
Uncontrolled
Cumulative % less
than diameter
5.5
7
11
23
43
62
72
Diameter,
micrometers
1.0
1.25
2.5
6.0
10.0
15.0
20.0
Controlled
(multiclone)
Cumulative % less
than diameter
13
14
23
39
50
63
81
Diameter, micrometers
1.0
1.25
2.5
6.0
10.0
15.0
20.0
Uncontrolled
Cumulative % less than
diameter
0.76
1.1
2.7
11
25
38
52
Controlled
(multiclone/scrubber)
Cumulative % less than
diameter
31
43
46
55
69
81
91
36
-------
TABLE 4-9. (continued)
Average of References 9 and 10 data
Diameter, micrometers
1.0
1.25
2.5
6.0
10.0
15.0
20.0
Uncontrolled
Cumulative % less than diameter
4.1
6.9
17
34
50
62
37
-------
TABLE 4-10. SUMMARY OF EMISSION DATA FOR BENTONITE PROCESSING3
Source
Rotary dryer
Rotary dryer
Rotary dryer
with fabric filter
Rotary dryer
with fabric filter
Rotary dryer
with ESP
Pollutant
Filterable PM
PM-10
Filterable PM
PM-10
Filterable PM
No.
of
runs
3
12C
3
3d
2
Data
rating
B
B
B
B
C
Emission factor, kg/Mg (Ib/ton)
Minimum
130 (270)
9.3 (19)
0.032
(0.064)
0.024
(0.048)
0.0078
(0.016)
Maximum
150 (300)
11 (21)
0.068
(0.14)
0.050
(0.10)
0.010
(0.020)
Average
140 (290)
10 (20)
0.050
(0.10)
0.037
(0.074)
0.0090
(0.018)
Ref
No.
7b
7b
7b
7b
T
Emission factor in kg/Mg (Ib/ton) of product. Factors represent uncontrolled emission unless
noted.
bPlantCl.
°Based on filterable PM emission factor and 12 runs of particle size distribution measurements,
which indicated an average of 7 percent PM-10.
dBased on filterable PM emission factor and three runs of particle size distribution measurements,
which indicated an average of 74 percent PM-10.
Tlant C3.
38
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TABLE 4-11. SUMMARY OF PARTICLE SIZE FOR BENTONITE PROCESSING3
Particle size, micrometers
1.0
1.25
2.5
6.0
10.0
15.0
20.0
Cumulative percent less than size
Rotary dryer, uncontrolledb
0.2
0.3
0.8
2.2
7.0
12
25
Rotary dryer with fabric
filter0
2.5
3.0
12
44
74
92
97
"Reference 7, Plant Cl. Data rated B.
bBased on average of 12 runs.
°Based on average of three runs.
TABLE 4-12. SUMMARY OF EMISSION DATA FOR FULLER'S EARTH PROCESSING3
Source
Rotary dryer, rotary cooler,
grinding and screening
operation, and packaging
operation with multiclone
and wet scrubber
Rotary dryer, rotary cooler,
and packing operation with
multiclone and wet
scrubber
Rotary dryer, rotary cooler,
and packaging operation
with multiclone and wet
scrubber
Pollutant
Filterable
PM
Filterable
PM
C02
No.
of
runs
3
3
3
Data
rating
A
A
A
Emission factor, kg/Mg (Ib/ton)
Minimum
0.28
(0.56)
0.55
(1.1)
230
(470)
Maximum
0.35
(0.69)
0.94
(1.9)
430
(870)
Average
0.32
(0.63)
0.69
(1.4)
310
(610)
Ref
No.
5
6
6
3Emission factor in kg/Mg (Ib/ton) of product.
39
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TABLE 4-13. SUMMARY OF EMISSION FACTORS FOR CLAY PROCESSING3
Raw material
type
Kaolin
Ball clay
Fire clay
Source
Spray dryer with fabric filter
Spray dryer with fabric filter
Apron dryer
Apron dryer
Multiple hearth furnace
Multiple hearth furnace
Multiple hearth furnace
Multiple hearth furnace with
venturi scrubber
Flash calciner
Flash calciner
Flash calciner
Flash calciner with fabric filter
Flash calciner with fabric filter
Vibrating grate dryer with fabric
filter
Rotary dryer
Rotary dryer with cyclone
Rotary dryer with cyclone/
scrubber
Rotary dryer
Rotary dryer with cyclone
Rotary dryer
Rotary calciner
Rotary calciner with multiclone
Pollutant
Filterable PM
C02
Filterable PM
C02
Filterable PM
Filterable PM-10
C02
Filterable PM
Filterable PM
Filterable PM-10
C02
Filterable PM
Filterable PM-10
Filterable PM
Filterable PM
Filterable PM
Filterable PM
Filterable PM-10
Filterable PM-10
C02
Filterable PM
Filterable PM
No. of
tests
3
1
1
1
1
1
2
1
1
1
1
1
1
1
2
2
2
2
2
6
2
1
Emission
factor
rating
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
Emission
factor, kg/Mg
(Ib/ton)
0.12
(0.23)
81
(160)
0.62
(1.2)
140
(280)
17
(34)
8.2
(16)
140
(280)
0.12
(0.23)
550
(1,100)
280
(560)
260
(510)
0.028
(0.055)
0.023
(0.046)
0.071
(0.14)
33
(65)
5.6
(11)
0.052
(0.11)
8.1
(16)
2.6
(5.1)
15
(30)
62
(120)
31
(61)
Ref
Nos.
1,7
1
2
2
4
4
4
4
4
4
4
4
4
7
8
8
8
8
8
8
9, 10
9
40
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TABLE 4-13. (continued)
Raw material
type
Fire clay
(cont'd)
Bentonite
Fuller's earth
Source
Rotary calciner with multiclone/
scrubber
Rotary calciner
Rotary calciner with multiclone
Rotary calciner with multiclone/
scrubber
Rotary calciner
Rotary calciner with multiclone/
scrubber
Rotary calciner with multiclone/
scrubber
Rotary dryer
Rotary dryer
Rotary dryer with fabric filter
Rotary dryer with fabric filter
Rotary dryer with ESP
Rotary dryer, rotary cooler,
grinding and screening
operation, and packaging
operation with multiclone and
wet scrubber
Rotary dryer, rotary cooler, and
packaging operation with
multiclone and wet scrubber
Rotary dryer, rotary cooler, and
packaging operation with
multiclone and wet scrubber
Pollutant
Filterable PM
Filterable PM-10
Filterable PM-10
Filterable PM-10
CO2
S02
NOX
Filterable PM
Filterable PM-10
Filterable PM
Filterable PM-10
Filterable PM
Filterable PM
Filterable PM
C02
No. of
tests
2
2
1
1
5
1
1
1
1
1
1
1
1
1
1
Emission
factor
rating
D
D
D
D
D
D
D
D
D
D
D
E
D
D
D
Emission
factor, kg/Mg
(Ib/ton)
0.15
(0.30)
20
(41)
15
(30)
0.031
(0.062)
300
(600)
3.8
(7.6)
0.87
(1.7)
140 (290)
10 (20)
0.050 (0.10)
0.037
(0.074)
0.0090
(0.018)
0.32 (0.63)
0.69 (1.4)
310
(610)
Ref
Nos.
9, 10
9, 10
9
10
9, 10
9
9
7
7
7
7
7
5
6
6
aEmission factors in kg/Mg (Ib/ton) of product.
41
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TABLE 4-13. (continued)
REFERENCES FOR SECTION 4
1. Report on Particulate Emissions From No. 3 Spray Dryer, American Industrial Clay Company, Sandersonville,
Georgia, July 21, 1975.
2. Report on Particulate Emissions From Apron Dryer, American Industrial Clay Company, Sandersonville, Georgia, July
21, 1975.
3. Emission Test Report: Thiele Kaolin, Sandersonville, Georgia, EMB-78-NMM-7, U. S. Environmental Protection
Agency, Research Triangle Park, NC, March, 1979.
4. Emission Test Report: Plant A, Confidential Business Information files, Document No. C-3-1, ESD Project No. 81/08,
U. S. Environmental Protection Agency, Research Triangle Park, NC, October, 1983.
5. Source Test Report, Plant B, Kiln Number 2 Outlet, Technical Services, Inc., Jacksonville, FL, February, 1979.
6. Source Test Report, Plant B, Number 1 Kiln Outlet Particulate Emissions, Technical Services, Inc., Jacksonville, FL,
February, 1979.
7. Calciners and Dryers in Mineral Industries-Background Information for Proposed Standards, EPA-450/3-85-025a, U.
S. Environmental Protection Agency, Research Triangle Park, NC, October, 1985.
8. Calciners and Dryers Emission Test Report, North American Refractories Company, Farber, Missouri, EMB Report 84-
CDR-14, U. S. Environmental Protection Agency, Research Triangle Park, NC, March 1984.
9. Emission Test Report: Plant A, Test 1, Confidential Business Information Files, Document No. C-7-12, ESD Project
No. 81/08, U. S. Environmental Protection Agency, Research Triangle Park, NC.
10. Calciners and Dryers Emission Test Report, A. P. Green Company, Mexico, Missouri, EMB Report 83-CDR-l, U. S.
Environmental Protection Agency, Research Triangle Park, NC, October 1983.
42
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TABLE 4-13. (continued)
5. AP-42 SECTION 11.25
A proposed new AP-42 Section 11.25, Clay Processing, is presented in the following pages as it would appear in
the document.
43
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