EPA-452/R-96-006
ESTIMATING AND CONTROLLING FUGITIVE LEAD EMISSIONS
FROM INDUSTRIAL SOURCES
Air Quality Strategies and Standards Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
April 1996
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Although the information in this document has been funded
wholly or in part by the United states Environmental Protection
Agency under contract No. 68-D3-0031 to Midwest Research
Institute, it does not necessarily reflect the views of the
Agency and no official endorsement should be inferred.
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TABLE OF CONTENTS
LIST OF FIGURES ix
LIST OF TABLES xiii
1.0 INTRODUCTION 1-1
1.1 BACKGROUND 1-1
1.2 PURPOSE OF DOCUMENT 1-2
1.3 DOCUMENT ORGANIZATION 1-3
1.4 REFERENCES FOR CHAPTER 1 1-4
2.0 FUGITIVE EMISSION SOURCES 2-1
2.1 FUGITIVE DUST EMISSIONS 2-1
2.1.1 Paved Roads 2-2
2.1.2 Unpaved Roads 2-6
2.1.3 Storage Piles 2-11
2.2 PROCESS FUGITIVE EMISSIONS 2-16
2.2.1 Solid Materials Handling Operations . 2-17
2.2.2 Materials Processing Operations . . . 2-18
2.2.3 Furnaces 2-18
2.2.4 Hot Metal Transfer and Processing . . 2-23
2.2.5 Metal Casting 2-23
2.2.6 Estimating Lead Emissions From
Process Fugitive Sources 2-23
2.3 REFERENCES FOR CHAPTER 2 2-25
3.0 CONTROL OF FUGITIVE EMISSIONS 3-1
3.1 FUGITIVE DUST EMISSION CONTROLS 3-1
3.1.1 Paved Road Control Measures 3-2
3.1.2 Unpaved Road Control Measures .... 3-8
3.1.3 Storage Pile Control Measures .... 3-15
3.2 PROCESS FUGITIVE EMISSION CONTROLS 3-20
3.2.1 Local Ventilation Systems 3-20
3.2.2 Building Enclosure/Evacuation .... 3-28
3.2.3 Other Process Fugitive Controls ... 3-30
3.3 REFERENCES FOR CHAPTER 3 3-30
4.0 PRIMARY LEAD SMELTING 4-1
4.1 PROCESS DESCRIPTION 4-1
4.1.1 Sintering 4-1
4.1.2 Reduction 4-4
4.1.3 Dressing 4-5
4.1.4 Refining 4-5
4.2 FUGITIVE EMISSION SOURCES . . 4-5
4.2.1 Fugitive Dust Sources 4-7
4.2.2 Process Fugitive Emissions Sources . 4-11
4.3 ESTIMATING FUGITIVE EMISSIONS 4-12
4.3.1 Fugitive Dust Emission Estimation . . 4-12
4.3.2 Process Fugitive Emission Estimation 4-13
111
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TABLE OF CONTENTS (continued)
4.4 FUGITIVE EMISSION CONTROLS 4-15
4.4.1 Fugitive Dust Emission Controls . . 4-15
4.4.2 Process Fugitive Emission Controls . 4-15
4.5 REFERENCES FOR CHAPTER 4 4-18
5.0 SECONDARY LEAD SMELTING 5-1
5.1 PROCESS DESCRIPTION 5-1
5.1.1 Storage and Handling Operations . . . 5-5
5.1.2 Charge Material Preparation 5-6
5.1.3 Smelting Furnace Operations 5-8
5.1.4 Refining and Casting Operations . . . 5-11
5.2 FUGITIVE EMISSION SOURCES 5-11
5.2.1 Fugitive Dust Sources 5-14
5.2.2 Process Fugitive Emissions Sources . 5-15
5.3 ESTIMATING FUGITIVE EMISSIONS 5-15
5.3.1 Fugitive Dust Emission Estimation . . 5-15
5.3.2 Process Fugitive Emission Estimation 5-20
5.4 FUGITIVE EMISSION CONTROLS 5-20
5.4.1 Fugitive Dust Emission Controls . . . 5-20
5.4.2 Process Fugitive Emission Controls . 5-22
5.5 REFERENCES FOR CHAPTER 5 5-28
6.0 LEAD-ACID BATTERY MANUFACTURING 6-1
6.1 PROCESS DESCRIPTION 6-1
6.1.1 Grid Casting 6-1
6.1.2 Paste Mixing 6-1
6.1.3 Three-Process Operation 6-3
6.1.4 Formation 6-3
6.1.5 Lead Oxide Production 6-3
6.1.6 Lead Reclamation 6-4
6.2 FUGITIVE EMISSION SOURCES 6-4
6.2.1 Fugitive Dust 6-4
6.2.2 Process Fugitives 6-5
6.3 ESTIMATING FUGITIVE EMISSIONS 6-5
6.3.1 Fugitive Dust 6-5
6.3.2 Process Fugitives 6-7
6.4 CONTROLLING FUGITIVE EMISSIONS 6-7
6.4.1 Fugitive Dust 6-7
6.4.2 Process Fugitives 6-7
6.5 REFERENCES FOR CHAPTER 6 6-8
7.0 GRAY IRON FOUNDRIES 7-1
7.1 PROCESS DESCRIPTION 7-1
7.2 FUGITIVE EMISSION SOURCES 7-5
7.2.1 Fugitive Dust 7-5
7.2.2 Process Fugitives 7-5
7.3 ESTIMATING FUGITIVE EMISSIONS 7-10
7.3.1 Fugitive Dust 7-10
7.3.2 Process Fugitives 7-12
iv
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TABLE OF CONTENTS (continued)
Page
7.4 CONTROLLING FUGITIVE EMISSIONS 7-12
7.5 REFERENCES FOR CHAPTER 7 7-16
8.0 PRIMARY COPPER SMELTING . 8-1
8.1 PROCESS DESCRIPTION 8-1
8.1.1 Drying 8-1
8.1.2 Smelting . . . 8-3
8.1.3 Converting 8-6
8.1.4 Slag Recycling 8-8
8.1.5 Fire Refining 8-8
8.2 FUGITIVE EMISSION SOURCES . . 8-9
8.2.1 Fugitive Dust 8-9
8.2.2 Process Fugitives 8-11
8.3 ESTIMATING FUGITIVE EMISSIONS 8-13
8.3.1 Fugitive Dust 8-13
8.3.2 Process Fugitives 8-16
8.4 CONTROLLING FUGITIVE EMISSIONS 8-17
8.5 REFERENCES ..... 8-20
9.0 SECONDARY COPPER SMELTING AND ALLOYING 9-1
9.1 PROCESS DESCRIPTION 9-1
9.1.1 Scrap Metal Pretreatment 9-4
9.1.2 Pyroprocessing . 9-4
9.2 FUGITIVE EMISSION SOURCES 9-6
9.2.1 Fugitive Dust 9-7
9.2.2 Process Fugitives 9-7
9.3 ESTIMATING FUGITIVE EMISSIONS ... 9-10
9.3.1 Fugitive Dust 9-10
9.3.2 Process Fugitives 9-14
9.4 FUGITIVE EMISSION CONTROLS 9-14
9.4.1 Fugitive Dust Emission Controls . . . 9-14
9.4.2 Process Fugitive Emission Controls . 9-16
9.5 REFERENCES FOR CHAPTER 9 9-18
10.0 SECONDARY ZINC SMELTING 10-1
10.1 PROCESS DESCRIPTION 10-1
10.1.1 Scrap Pretreatment 10-1
10.1.2 Melting 10-5
10.1.3 Refining . . 10-5
10.1.4 Steel Plant EAF Dust Processing . . . 10-7
10.2 FUGITIVE EMISSION SOURCES 10-8
10.2.1 Fugitive Dust 10-10
10.2.2 Process Fugitives 10-11
10.3 ESTIMATING FUGITIVE EMISSIONS 10-12
10.3.1 Fugitive Dust 10-12
10.3.2 Process Fugitives 10-14
10.4 CONTROLLING FUGITIVE EMISSIONS 10-14
10.5 REFERENCES FOR CHAPTER 10 10-18
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TABLE OF CONTENTS (continued)
Page
11.0 SOLDER AND AMMUNITION MANUFACTURING 11-1
11.1 PROCESS DESCRIPTION 11-1
11.1.1 Solder Manufacturing 11-1
11.1.2 Ammunition Manufacturing 11-5
11.2 FUGITIVE EMISSION SOURCES . 11-5
11.2.1 Fugitive Dust 11-5
11.2.2 Process Fugitives 11-6
11.3 ESTIMATING FUGITIVE EMISSIONS 11-7
11.3.1 Fugitive dust 11-7
11.3.2 Process Fugitives 11-9
11.4 CONTROLLING FUGITIVE EMISSIONS 11-9
11.5 REFERENCES FOR CHAPTER 11 11-11
12.0 LEAD-BASED INORGANIC PIGMENT MANUFACTURING .... 12-1
12.1 PROCESS DESCRIPTION 12-1
12.1.1 Lead Oxide Production 12-2
12.1.2 Lead-Based Inorganic Pigment
Production 12-4
12.2 FUGITIVE EMISSION SOURCES 12-4
12.3 ESTIMATING FUGITIVE EMISSIONS 12-5
12.3.1 Fugitive Dust 12-5
12.3.2 Process Fugitives 12-8
12.4 FUGITIVE EMISSION CONTROLS 12-9
12.4.1 Fugitive Dust Emission Controls . . . 12-9
12.4.2 Process Fugitive Emission Controls . 12-10
12.5 REFERENCES FOR CHAPTER 12 12-10
13.0 PRESSED AND BLOWN GLASS MANUFACTURING 13-1
13.1 PROCESS DESCRIPTION 13-1
13.1.1 Raw Materials 13-1
13.1.2 Furnace 13-3
13.2 EMISSIONS AND CONTROLS . . 13-7
13.3 REFERENCES FOR CHAPTER 13 13-8
APPENDIX A. PROCEDURES FOR SAMPLING SURFACE/BULK
MATERIALS A-l
A.I UNPAVED ROADS A-2
A. 2 PAVED ROADS A-9
A. 3 STORAGE PILES A-15
APPENDIX B. PROCEDURES FOR LABORATORY ANALYSIS OF
SURFACE/BULK SAMPLES . B-l
B.I SAMPLE SPLITTING B-3
B.2 MOISTURE ANALYSIS B-9
B.3 SILT ANALYSIS B-13
B.4 REFERENCES FOR APPENDIX B B-17
APPENDIX C. INDUSTRIAL VEHICLE WEIGHTS C-l
VI
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TABLE OF CONTENTS (continued)
Page
APPENDIX D. METEOROLOGICAL DATA FOR SECONDARY SMELTER
LOCATIONS D-l
REFERENCES FOR APPENDIX D . D-5
APPENDIX E. EXAMPLE FUGITIVE EMISSION INVENTORY
CALCULATIONS HYPOTHETICAL SECONDARY LEAD
SMELTER E-l
REFERENCES FOR APPENDIX E E-7
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LIST OF FIGURES
Figure 2-1. Mean annual number of days with at least
0.01 in. of precipitation 2-10
Figure 2-2. Typical blast furnace system for secondary
lead production 2-20
Figure 2-3. Typical reverberatory furnace system for
secondary lead production 2-21
Figure 3-1. Watering control effectiveness for unpaved
travel surfaces 3-11
Figure 3-2. Pending 3-12
Figure 3-3. Petroleum-based chemical dust suppressant
conrol efficiency model 3-14
Figure 3-4. Overview of modified local exhaust
ventilation system 3-22
Figure 3-5. Blast furnace slag tapping hood 3-23
Figure 3-6. Skip hoist ground level loading station . . 3-24
Figure 3-7. Alternate suggested design concept for blast
furnace launder and block casting hoods . . 3-25
Figure 3-8. Suggested design concept for blast furnace
lead tapping hood system (lead tap, launder,
and block casting 3-26
Figure 3-9. Rotary furnace charging and tapping
controls 3-27
Figure 3-10. Finished metal ladle cooling hood 3-29
Figure 4-1. Typical primary lead processing scheme . . . 4-2
Figure 4-2. Updraft sintering with weak gas
recirculation '• • 4-3
Figure 5-1. Typical secondary lead smelting and refining
scheme 5-3
Figure 5-2. Suggested design concept for refining
kettle hoods 5-24
ix
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LIST OF FIGURES (continued)
Page
Figure 5-3. Suggested design concept for dross pot
hoods 5-26
Figure 5-4. Flash agglomeration furnace 5-27
Figure 6-1. Process flow diagram for storage battery
production 6-2
Figure 7-1. Composite flow diagram for the gray iron
foundry industry 7-3
Figure 7-2. Mold and core making 7-4
Figure 8-1. Typical primary copper-smelting process . . 8-2
Figure 8-2. Reverberatory furnace ..... 8-5
Figure 8-3. Copper converter ... 8-7
Figure 8-4. Process flow diagram for primary copper
smelting showing potential fugitive PM
emission points 8-10
Figure 9-1. Secondary copper smelting process 9-2
Figure 10-1. Secondary zinc recovery process 10-3
Figure 10-2. Zinc retort distillation furnace 10-6
Figure 10-3. Muffle furnace and condenser 10-6
Figure 10-4. Process flow diagram for secondary zinc
production showing potential fugitive dust
and process fugitive PM emissions points . . 10-9
Figure 12-1. Lead oxide Barton Pot process 12-3
Figure 13-1. Process flow diagram for the glass manufacturing^-2
Figure 13-2. General diagram of a batch plant 13-4
Figure 13-3. Side port continuous regenerative furnace . 13-5
Figure 13-4. End port continuous regenerative furnace . . 13-6
Figure A-l. Sampling locations for unpaved roads .... A-5
Figure A-2. Sampling data form for unpaved roads .... A-7
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LIST OF FIGURES (continued)
Page
Figure A-3. Sampling locations for paved roads A-ll
Figure A-4. Sampling data form for paved roads A-7
Figure A-5. Sampling data form for storage piles .... A-8
Figure B-l. Sample dividers (riffles) B-4
Figure B-2. Coning and quartering B-6
Figure B-3. Sample moisture analysis form B-ll
Figure B-4. Sample silt analysis form B-15
Figure E-l. Plot plan for Facility A E-3
XI
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Xll
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LIST OF TABLES
TABLE 2-1.
TABLE 2-2.
TABLE 2-3.
TABLE 2-4.
TABLE 2-5.
TABLE 2-6.
TABLE 3-1.
TABLE 3-2.
TABLE 3-3.
TABLE 3-4.
TABLE 3-5.
TABLE 4-1.
TABLE 4-2.
TABLE 4-3.
TABLE 4-4.
TABLE 4-5.
TABLE 4-6.
INDUSTRIAL PAVED ROAD SILT LOADINGS
VALUES FOR PAVED ROAD PARTICLE SIZE
MULTIPLIER
METHODS FOR ANALYZING MATERIAL SAMPLES
FOR LEAD
VALUES FOR UNPAVED ROAD PARTICLE SIZE
MULTIPLIER . . .
TYPICAL SILT CONTENT VALUES OF SURFACE
MATERIAL ON INDUSTRIAL AND RURAL UNPAVED
ROADS
VALUES FOR MATERIALS HANDLING PARTICLE
SIZE MULTIPLIER ....
INDUSTRIAL PAVED ROAD DUST DEPOSITION
MECHANISMS AND PREVENTIVE CONTROLS .....
MEASURED EFFICIENCY VALUES FOR PAVED ROAD
CONTROLS
CONTROL TECHNIQUES FOR UNPAVED TRAVEL
SURFACES
CONTROL TECHNIQUES FOR STORAGE PILES ....
SUMMARY OF AVAILABLE CONTROL EFFICIENCY
DATA FOR WIND FENCES/BARRIERS
FUGITIVE LEAD EMISSION SOURCES FOR A PRIMARY
LEAD SMELTER
ESTIMATED 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
MOISTURE, SILT, AND LEAD CONTENT OF STORAGE
PILE MATERIALS AT TWO PRIMARY LEAD SMELTERS
PROCESS FUGITIVE EMISSION FACTORS FOR PRIMARY
LEAD SMELTING
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2-3
2-4
2-5
2-7
2-9
2-13
3-3
3-7
3-9
3-16_
3-18
4-6
4-8
4-10
4-11
4-14
4-14
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LIST OF TABLES (continued)
TABLE 4-7.
TABLE 5-1.
TABLE 5-2.
TABLE 5-3.
TABLE 5-4.
TABLE 5-5.
TABLE 5-6.
TABLE 5-7.
TABLE 5-8.
TABLE 6-1.
TABLE 7-1.
TABLE 7-2.
TABLE 7-3.
TABLE 8-1.
TABLE 8-2.
TABLE 8-3.
SPECIFIC PROCESS FUGITIVE LEAD EMISSION
SOURCES AND POTENTIAL CONTROLS AT 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
EMISSION FACTORS FOR PROCESS FUGITIVE
EMISSION SOURCES IN SECONDARY LEAD SMELTERS
LEAD CONTENT OF SECONDARY LEAD SMELTER
MATERIALS
EMISSION FACTORS FOR PROCESS FUGITIVE
EMISSION SOURCES IN SECONDARY
LEAD SMELTERS
LEAD-ACID BATTERY MANUFACTURING—TYPICAL
CONTROL DEVICES . . .
FUGITIVE EMISSION SOURCES IN IRON FOUNDRIES
FUGITIVE EMISSION FACTORS FOR IRON
FOUNDRIES
PROCESS FUGITIVE EMISSION CONTROLS FOR
GRAY IRON FOUNDRIES
PRIMARY COPPER SMELTING FACILITIES
PRIMARY COPPER SMELTING FUGITIVE DUST
EMISSION SOURCES
PRIMARY COPPER SMELTING PROCESS FUGITIVE
EMISSION SOURCES
Page
4-17
5-2
5-12
5-13
5-17
5-18
5-19
5-20
5-21
6-8
7-6
7-13
7-14
8-3
8-11
8-12
XIV
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LIST OF TABLES (continued)
Page
TABLE 8-4. LEAD CONTENT OF PM EMISSIONS AND SLAGS
FROM PRIMARY COPPER SMELTING 8-15
TABLE 8-5. FUGITIVE PM EMISSION FACTORS FOR PRIMARY
COPPER SMELTING PROCESS SOURCES 8-16
TABLE 8-6. FUGITIVE LEAD EMISSION FACTORS FOR
PRIMARY COPPER SMELTING 8-17
TABLE 8-7. CONTROL TECHNIQUES FOR PRIMARY COPPER SMELTING
PROCESS FUGITIVE PM EMISSION SOURCES .... 8-18
TABLE 9-1. SUMMARY OF SECONDARY COPPER SMELTERS IN
THE UNITED STATES 9-3
TABLE 9-2. SECONDARY COPPER SMELTING FUGITIVE DUST
EMISSION SOURCES 9-8
TABLE 9-3. ESTIMATES OF LEAD FUGITIVE DUST EMISSION
RATES FROM PAVED AND UNPAVED ROADS AT A
SECONDARY COPPER SMELTER 9-8
TABLE 9-4. SECONDARY COPPER SMELTING PROCESS
FUGITIVE EMISSION SOURCES 9-9
TABLE 9-5. SUMMARY OF PAVED ROAD DUST SAMPLES AT
AT SECONDARY COPPER SMELTER 9-12
TABLE 9-6. SUMMARY OF PAVED ROAD DATA FOR A
SECONDARY COPPER SMELTER 9-12
TABLE 9-7. SUMMARY OF PAVED ROAD DATA FOR A
SECONDARY COPPER SMELTER 9-13
TABLE 9-8. MOISTURE AND LEAD CONTENT FOR SECONDARY
COPPER SMELTER STORAGE PILES 9-13
TABLE 9-9. PROCESS EMISSION FACTORS FOR SECONDARY
COPPER SMELTING 9-15
TABLE 9-10. SUMMARY OF FUGITIVE DUST CONTROLS AT
A SECONDARY COPPER SMELTER 9-17
TABLE 10-1. SECONDARY ZINC FACILITIES 10-2
TABLE 10-2. SECONDARY ZINC FUGITIVE DUST
EMISSION SOURCES 10-10
XV
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LIST OF TABLES (continued)
TABLE 10-3.
TABLE 10-4.
TABLE 10-5.
TABLE 11-1.
TABLE 11-2.
TABLE 12-1.
TABLE 12-2.
TABLE 12-3.
TABLE C-l.
TABLE D-l.
TABLE E-l.
TABLE E-2.
SECONDARY ZINC PROCESS FUGITIVE
EMISSION SOURCES
FUGITIVE PARTICULATE EMISSION FACTORS
FOR SECONDARY ZINC SMELTING
CONTROL TECHNIQUES FOR SECONDARY ZINC
PROCESS FUGITIVE EMISSION SOURCES
CONSUMERS OF LEAD FOR SOLDER IN 1987 . . . .
SUMMARY OF EMISSION FACTORS FOR
SOLDER MANUFACTURING
FUGITIVE DUST EMISSION SOURCES FOR THE
PRODUCTION OF LEAD OXIDE AND PIGMENTS . ,
PROCESS FUGITIVE EMISSION SOURCES FOR THE
PRODUCTION OF LEAD OXIDE AND PIGMENTS . .
EMISSION FACTORS FOR LEAD EMISSIONS FROM
LEAD OXIDE AND PIGMENT PRODUCTION . . . .
INDUSTRIAL VEHICLE WEIGHTS
METEOROLOGICAL DATA FOR SECONDARY SMELTER
LOCATIONS
SUMMARY OF DELIVERY TRUCK TRAFFIC AT FACILITY
CALCULATION OF FUGITIVE EMISSION RATES . . .
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10-15
10-16
11-3
11-10
12-5
12-6
12-8
C-l
D-2
A E-6
E-8
XVI
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1.0 INTRODUCTION
1.1 BACKGROUND
Since the promulgation of the National Ambient Air Quality
Standard (NAAQS) for lead in 1978, ambient concentrations of lead
have declined dramatically, primarily as the result of the phase
out of leaded gasolines. However, due to continuing concern over
exceedances of the lead NAAQS and the residual risk associated
with point sources of lead, the Environmental Protection Agency's
(EPA's) Office of Air Quality Planning and Standards (OAQPS)
established the Lead NAAQS Attainment Strategy in 1990. This
strategy targets air emissions of lead from stationary sources
and focuses on attainment of the lead NAAQS through more
extensive monitoring, compliance inspections, and regulation.
Since the establishment of the Lead NAAQS Attainment Strategy,
14 areas around 30 stationary sources have been designated
nonattainment for lead, 1 area has been proposed nonattaimnent,
2 areas have been issued State implementation plan (SIP) calls,
and 17 sources have been determined to be out of compliance with
current emission standards.
In 1993, a study was conducted for EPA's Air Quality
Management Division to estimate annual lead emissions from
industries that were known or suspected to emit significant
quantities of lead and, thus, were to be the industries included
in the lead NAAQS attainment strategy in the future.1 Based on
the findings of that study and other information available, the
following industries were identified as potentially significant
sources of lead emissions, in order to provide guidance to States
in the preparation of SIP's: primary lead smelting, secondary
1-1
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lead smelting, lead-acid battery manufacturing, gray iron
foundries, primary copper smelting, secondary copper smelting,
secondary zinc smelting, solder manufacturing, inorganic pigment
manufacturing, ammunition manufacturing, and pressed and blown
leaded glass manufacturing. Therefore, further reductions in
lead emissions must be achieved in these industries. Because
point sources at these industries generally are controlled,
fugitive lead emissions, particularly from fugitive dust sources,
are believed to contribute significantly to exceedances of the
lead NAAQS in the vicinity of stationary sources of lead
emissions.
On the subject of fugitive dust control, EPA published the
document Fugitive Dust Background Document and Technical
Information Document for Best Available Control Measures, which
addresses the available measures for controlling emissions of
particulate matter less than 10 micrometers in diameter (PM-10)
from fugitive dust sources. However, the effectiveness of these
PM-10 control measures in controlling lead fugitive emissions has
not been fully evaluated.
Fugitive PM emissions from industrial process sources were
addressed in the 1977 report Technical Guidance for Control of
Industrial Process Fugitive Particulate Emissions
(EPA-450/3-77-010), and lead emissions from industrial sources
were addressed in the 1977 document Control Techniques for Lead
Air Emissions From Stationary Sources (EPA-450/2-77-012).
However, neither of these documents focused on fugitive lead
emissions from industrial process sources. In addition, these
two documents did not address all of the industries that were
suspected to be significant emitters of lead to the ambient air.
1.2 PURPOSE OF DOCUMENT
The purpose of this document is threefold:
1. To identify fugitive dust and process fugitive sources
of lead emissions for specific industrial source categories that
are suspected to contribute significantly to nationwide lead
emissions;
1-2
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2. To present and evaluate the available information on
procedures for estimating and controlling lead fugitive dust and
process fugitive emissions for these target source categories;
and
3. To present the available information on measures
currently used by these target industries to control fugitive
dust and process fugitive emissions.
1.3 DOCUMENT ORGANIZATION
Section 2.0 of this report presents a general discussion of
fugitive dust and process fugitive emission sources. This is
followed in Section 3.0 by a description of measures for
controlling fugitive dust and industrial process fugitive
emissions. The remaining sections (4.0 through 13.0) of this
report present process descriptions and descriptions of fugitive
emission sources and controls for the following industrial source
categories: primary lead smelting, secondary lead smelting,
lead-acid battery manufacturing, gray iron foundries, primary
copper smelting, secondary copper smelting, secondary zinc
smelting, solder and ammunition manufacturing, and inorganic
pigment manufacturing, respectively.
Fugitive lead emissions from secondary aluminum processing
were also investigated under this study. However, no information
on lead emissions from secondary aluminum processing could be
located. According to an industry expert, the only scrap
materials processed by secondary aluminum plants that could have
significant lead contents are cans that are labeled with lead-
based paint. However, in such cases, the lead content of the
overall feed material to the process would be negligible.2
Therefore, lead emissions from secondary aluminum processing also
can be assumed to be negligible. Consequently, the secondary
aluminum processing industry is not addressed further in this
report.
1.4 REFERENCES FOR CHAPTER 1
1. Scoping Study for Lead Emissions From Industrial Sources
Within SIC'S 3229, 3331, 3356, 3482, 3483, 3691, 7997, and
7999, prepared for Air Quality Management Division,
1-3
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U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, TRC Environmental Corporation, Chapel
Hill, North Carolina; June 1993.
2. Telephone communication from P. Plunkert, Bureau of Mines,
U. S. Department of the Interior, to R. Marinshaw, Midwest
Research Institute, Lead Emissions from Secondary Aluminum
Processing, December 20, 1993.
1-4
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2.0 FUGITIVE EMISSION SOURCES
Fugitive emission sources can be divided into two broad
categories—process fugitive emission sources and 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.
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 by machinery
acting on exposed materials.1
The following sections present general discussions of the
various types of fugitive emission sources. Fugitive dust
sources are described, and typical process fugitive emission
sources are discussed.
2.1 FUGITIVE DUST EMISSIONS
Fugitive dust sources include paved and unpaved traffic
areas and storage piles. Particulate matter (PM) emissions occur
from these sources when previously deposited material is
reentrained by vehicle traffic, the loading and unloading
equipment, or the action of the wind. For most industrial
plants, paved and unpaved roads are the primary sources of
fugitive dust emissions. Fugitive dust emissions from handling
operations for storage pile materials 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.
2-1
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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 result
from materials handling and wind erosion of storage piles are
described. The primary sources of information for the material
presented in this section on fugitive dust emissions are the EPA
publications Fugitive Dust Background Document and Technical
Information Document for Best Available Control Measures, and
Compilation of Air Pollutant Emission Factors. Volume I;
Stationary Point and Area Sources. The reader should consult
those two publications for the most current information on
fugitive dust emission sources, estimation, and control.
2.1.1 Paved Roads2
Fugitive dust emissions from paved roads depend upon the
loose surface material and traffic characteristics of the road.
These emissions have been determined to vary according to the
surface material loading, silt content of surface material, and
the average weight of vehicles traveling on the road. The
surface material loading is the amount of loose dust on the road
surface and is measured in 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 micrometers [pirn] in diameter) in the loose
surface dust. The product of the silt fraction and surface dust
loading constitute the silt loading and is abbreviated "L." Some
typical values for silt loadings on industrial paved roads are
presented in Table 2-1.
The magnitude of fugitive lead emissions (or emissions of
any other substance) may be estimated by direct proportion with
the percent of lead (or substance of concern) by weight 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.
2-2
-------
TABLE 2-1. INDUSTRIAL PAVED ROAD SILT LOADINGS
Industry
Copper smelting
Iron and steel
production
Asphalt batching
Concrete batching
Sand and gravel
processing
Municipal solid
waste landfill
Quarry
No. of
sites
1
9
1
1
1
2
1 .
NO Of
samples
3
48
3
3
3
7
6
Silt, percent w/w
Range
15.4-21.7
1.1-35.7
2.6-4.6
5.2-6.0
6.4-7.9
—
—
Mean
19.0
12.5
3.3
5.5
7.1
—
—
No. of
travel
lanes
2
2
1
2
1
2
2
Silt loading, g/m2
Range
188-400
0.09-79
76-193
11-12
53-95
1.1-32.0
2.4-14
Mean
292
9.7
120
12
70
7.4
8.2
NJ
I
u
Reference 2.
-------
(2-1)
The fugitive dust emission factor for paved roads can be
determined by the following equation:
E = k (sL/2)065 (W/3)1-5
where:
E = fugitive dust emission factor
k = base emission factor for particle size range and units
of interest (see Table 2-2 below)
sL = road surface silt loading (g/m2)
W = average weight (tons) of the vehicles traveling the road
TABLE 2-2.
VALUES FOR PAVED ROAD PARTICLE SIZE
MULTIPLIERS
Size range,
/xm
2.5
10
15
30°
Multiplier kb
kg/VKT
0.00021
0.00046
0.00055
0.024
kg/VMT
0.00033
0.00073
0.00090
0.038
Ib/VMT
0.0073
0.016
0.020
0.082
aReference 2.
bunits shown are grams per vehicle kilometer traveled (g/VKT) ,
grams per vehicle mile traveled (g/VMT) , and pounds per vehicle
mile traveled (Ib/VMT).
GThe fraction of PM equal to or less than 30 jti& in aerodynamic
diameter is sometimes termed "suspendable particulate" (SP) and
is often used as a surrogate for TSP.
Fugitive lead emission factors in units of kilograms per vehicle
kilometer travelled (kg/VMT) or pounds per vehicle mile travelled
(Ib/VMT) can be determined by modifying Equation 2-1 to
incorporate the lead content of the silt and the particle size
multiplier for TSP as follows:
Epb = 0.024 (C/100) (SL/2)065 (W/3)1'5 (2-2)
= 2.9 X 10'5 (C) (SL)065 (W)15 (kg/VKT)
= 1.0 x 10" (C) (sL)065 (W)1-5 (Ib/VMT)
where
lead emission factor, kg/VKT (Ib/VMT) ;
average percent of lead by weight in the silt fraction;
2-4
-------
sL = road surface silt loading, g/m2; and
W = average vehicle weight, tons.
Road surface silt loading (sL in Equation 2-2) can be
determined using the procedures described in Appendix A,
Procedures for Sampling Surface/Bulk Materials, and Appendix B,
Procedures for Laboratory Analysis of Surface/Bulk Samples. The
percent of lead in the silt fraction (C in Equation 2-2) can be
TABLE 2-3. METHODS FOR ANALYZING MATERIAL SAMPLES FOR LEAD3
Analytical Method
No.
3050
6010
7420
7421
Title
Acid Digestion of Sediments,
Sludges, and Soils
Inductively Coupled Plasma
Atomic Emission Spectroscopy
Lead (Atomic Absorption, Direct
Aspiration)
Lead (Atomic Absorption,
Furnace Technique)
Comments
For sample
preparation
Sample analysis;
detection limit:
42 Mg/L
Sample analysis;
detection limit:
0.1 mg/L
Sample analysis;
detection limit:
1 /*g/L
aReference 3.
determined using SW-846, Test Methods for Evaluating Solid Waste.
Table 2-3 summarizes the specific analytical methods that can be
used. Appendix C provides vehicle weights (W) for several types
of vehicles used by industry.
Plant traffic volume (VKT [VMT] in Equation 2-2) 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 at a secondary lead smelter.
Typically, these battery delivery vehicles will follow a
2-5
-------
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 length of the path and the average
number of deliveries daily. (If the vehicles make a round trip,
the number of deliveries is doubled). The average daily number
of deliveries 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. Average vehicle
weight can also be obtained from plant records.
One mitigating factor needs to be considered in estimating
internal transfer vehicular emissions. Many facilities have
partially or completely enclosed process operations, and some
storage areas also may be contained in these 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 for partial enclosures and more
for complete enclosures) should be considered for such
situations.
2.ii 2 Unpaved Roads1
As is the case for paved roads, fugitive dust emissions
occur whenever a vehicle travels over an unpaved surface. Unlike
2-6
-------
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 1970s. 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 fr.om 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, mean
number of wheels, and rainfall frequency. The emission factor
equation for unpaved roads also includes a particle size
multiplier. Values for this particle size multiplier are
provided in Table 2-4.
TABLE 2-4. VALUES FOR UNPAVED ROAD
PARTICLE SIZE MULTIPLIER3
Particle size, /xm
<30
<15
<10
<5
<2.5
k
1.0
0.50
0.36
0.20
0.095
aReference 4.
The fugitive dust emission factor for unpaved roads per unit
of vehicle distance traveled can be estimated by the following
equation3:
2-7
-------
- -§• W (If5
* (lb/VMT>
(C (
where :
E = emission factor, kg/VKT (Ib/VMT) ;
k = particle size multiplier;
s = average silt content of road surface material, percent;
S = average vehicle speed, km/h (mil/h) ;
W = average vehicle weight, Mg (ton) ;
w = average number of wheels (dimensionless) ; and
p = number of days per year with >0.254 mm (0.01 in.) of
precipitation.
Measured silt values for a number of industries are given in
Table 2-5. As is the case for fugitive dust emission factors for
paved roads, 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 2-1 gives the geographical distribution of the mean annual
number of wet days per year in the United States.
Fugitive lead emission factors in units of mass per vehicle
distance travelled can be determined by modifying Equation (2-3)
to incorporate the lead content of the silt and the particle size
multiplier for TSP as follows:
Epb = (2.0 x lO'8) (C) (s) (S) (W)07(w)05(365-p) (kg/VKT) (2-4)
= (1.0 X lO'7) (C) (S) (S) (W)a7(W)as(365-p) (Ib/VMT)
where :
EM, = the lead emission factor, g/VKT (Ib/VMT) ;
C = percent by weight of lead in the silt fraction; and
the other variables are as defined above.
The average silt content (s) of the road surface material
can be determined using the procedures described in Appendices A
and B, and Appendix C can be used to estimate weights (W) of
2-8
-------
TABLE 2-5. TYPICAL SILT CONTUES 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
Municipal roads
Municipal solid waste
landfills
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 /crushe
d
limestone
Dirt
Unspecified
Disposal
routes
Plant sites
1
19
1
2
2
1
2
3
3
2
3
7
3
4
Test
samples
3
135
3
10
21
8
2
21
10
5
9
32
26
20
Silt, percent by weight
Range
16-19
0.2-19
4.1-6.0
2.4-16
3.7-15
2.4-7.1
4.9-5.3
2.8-18
7.2-25
18-29
5.0-13
1.0-68
0.4-13
2.2-22
Mean
17
6.0
4.8 .
10
7.4
4.3
5.1
8.4
17
24
8.9
12
5.7
6.4
to
I
vo
aReference 2.
-------
to
I
0 S0100 200 300 400 SOO
120
Figure 2-1. Mean annual number of days with at least 0.01 in. of precipitation
8
-------
certain types of vehicles. Average vehicle speeds (S) and number
of vehicle wheels can be obtained from plant records or can be
estimated easily.• Local meteorological data can be used to
estimate the average number days with at least 0.25 mm (0.01 in.)
of precipitation (p). In the absence of actual meteorological
data, Figure 2-1 can be used to estimate this parameter.
Table 2-3 identifies the methods for determining the lead content
of the silt (C).
One of the assumptions inherent in Equation 2-4 is that the
lead fraction in the PM emitted from unpaved roads is equivalent
to the lead fraction in the road silt. However, one study, in
which unpaved road dust and downwind ambient PM samples were
analyzed for 16 metals, indicates that the concentration of a
metal in an ambient PM sample collected downwind of unpaved roads
may be somewhat less than, and as low as 50 percent of, the
concentration of the same metal in the silt fraction of road
dust.5 However, the data from the study were inadequate to
develop an equation that could be used to predict ambient metal
concentrations downwind of unpaved roads reliably.
2.1.3 Storage Piles'
In most industrial settings, materials are stored uncovered
in outside locations. Although this pratice facilitates transfer
of materials into and out of storage, it also subjects the
storage to several forces that can introduce dust 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, fugitive dust emissions from storage
piles are generally insignificant in comparison to fugitive dust
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 dust
2-11
-------
emissions from storage piles that are enclosed or otherwise
controlled (e.g. wetting, covers, partial enclosure, etc.) will
generally be much less than the emissions that would originate
from the same storage pile without the protection of the
controls.
2.1.3.1 Equipment Traffic in Storage Areas. Fugitive dust
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 2-4) 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 in Equation 2-4 when
calculating emissions 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; 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 equation can be used to estimate fugitive dust
emissions from materials handling4:
2-12
-------
1.3
E = k(0.0016)
k(0.0032)
1.4
1.3
(kg/Mg)
(2-5)
(Ib/ton)
where:
E = emission factor, kg/Mg material handled (Ib/ton);
k = particle size multiplier;
U = mean wind speed, m/s (mph); and
M = material moisture content, percent.
Values for the particle size multiplier are provided in
Table 2-6.
TABLE 2-6. VALUES FOR MATERIALS
HANDLING PARTICLE SIZE MULTIPLIER3
Particle size, /*m
<30
<15
<10
<5
<2.5
k
0.74
0.48
0.35
0.20
0.11
aReference 4.
Fugitive lead emission factors can be determined by
modifying Equation 2-5 to incorporate the lead content of the
silt and the particle size multiplier for TSP as follows:
l.l x 10'5 (C) kg/Mg
M1'4
7.7 x 10-6 (C) ^ Ib/ton
M1'4
(2-6)
2-13
-------
where:
EH, = the lead emission factor, kg/Mg (Ib/ton) ;
C = percent by weight of lead in the silt fraction;
and the other variables are as defined above.
The average material moisture content (M) of the storage
pile material can be determined using the procedures described in
Appendices A and B. Local meteorological data can be used to
estimate the mean wind speed (U). Table 2-3 identifies the
methods for determining the lead content of the material (C).
It should be emphasized that Equation 2-8 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.4
2.1.3.3 Wind Erosion.1 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
2-14
-------
fugitive dust emissions from wind erosion of active storage
piles4:
E = 1.9 fy £||FP {§) (kg/d-hectare) (2-7)
E = 1*7 ^P *
where :
E = emission factor, kg/d-hectare (Ib/d-acre) ;
s = average silt. content of storage pile material, percent;
p = number of days per year with X).25 mm (0.01 in.) of
precipitation
f = percentage of time that the unobstructed wind speed
exceeds 5.4 m/sec (12 mph) at the mean pile height.
Equation 2-7 can be used to determine the fugitive dust TSP
emission factor for wind erosion of active storage piles.
Although the equation does not include a particle size
multiplier, the emission factor for PM-10 emissions can be
estimated as half of the TSP emission factor determined from
Equation 2-7. Fugitive lead emission factors can be determined
by modifying Equation 2-7 to incorporate the lead content of the
silt:
Ep,, = 3.6 x 10"6 (C) (s) (365-p) (f) (kg/d-hectare) (2-8)
= 3.2 x ID"6 (C) (s) (365-p) (f) (Ib/d-acre)
where :
Epb = the lead emission factor, kg/d-hectare (Ib/d-acre);
C = percent by weight of lead in the silt fraction;
and the other variables are as defined above.
The average silt content (s) of the storage pile material
can be determined using the procedures described in Appendices A
and B. Local meteorological data can be used to estimate the
average number days with at least 0.25 mm (0.01 in.) of
precipitation (p) and the percentage of time that the
unobstructed wind speed exceeds 5.4 m/sec (12 mph). In the
absence of actual meteorological data, Figure 2-1 can be used to
2-15
-------
estimate rainfall frequency. Table 2-3 identifies the methods
for determining the lead content of the silt (C).
A more complex model has been developed for estimating PM-10
emissions from wind erosion of inactive storage piles. Due to
its complexity, a discussion of that model is beyond the scope of
this report. References 1 and 4 provide details on the
development and use of the model. A computer program is
available through EPA's Emission Inventory Branch to simplify use
of the model.
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 (i.e., 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, crushing, and screening operations,
as well as intermediate material handling operations, such as hot
metal transport and solids conveying.
As a class of sources, process fugitive emission sources are
more difficult to characterize in a generic fashion than are
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 particular, process fugitive emissions vary widely
with respect to configuration of the release point, plume
geometry and temperature, and size distribution of the PM. These
industry- and facility-specific factors affect emission rates and
the feasibility and performance of different control
alternatives.
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,
2-16
-------
furnaces, 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 Sections 4.0 to 15.0.
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 these operations occur after, the material leaves the raw
material storage area (the type of materials discussed in this
section frequently 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 PM. The plume
configuration and flow properties generally are controlled by
ventilation airflows in the vicinity of the transfer point.
2-17
-------
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,
increasing 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 discharged from the process at ambient temperatures
(with sinter crushing and screening being the primary
exceptions). As with materials handling operations, the PM
emitted consists primarily of relatively coarse particles, 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
2-18
-------
lead oxide and to produce a feed material with suitable physical
properties for charging to the blast furnace. Figures 2-2 and
2-3 present schematics of typical blast and reverberatory
furnaces. Obviously, these furnaces differ significantly with
respect to configuration. They also differ 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.
2-19
-------
©
K)
I
to
o
BATTERY SCRAP. DROSSES.
OXIDES. REVERBERATORY
SLAG. RERUN SLAG. SCRAP
IRON. COKE. LIMESTONE
SLAQ BLASTFURNACE LEAD
EMISSION SOURCES
1 CHARGING (FUGITIVE)
2 SLAQ TAPPING (FUGITIVE)
3 LEAD TAPPING/CASTING (FUGITIVE)
4 METALLURGICAL (STACK)
AFTERBURNER . COOLING TUBES
COOLING BLEED AIR
DUST RECYCLED
Figure 2-2. Typical blast furnace system for secondary lead production.
-------
EMISSIONS
I
to
LEAD SCRAP. BATTERY 1
PLATES. OXIDES >
GAS OR
FUEL OIL
CHARGE
REVERBERATORY FURNACE
COOLING TUBES
COOLING BLEED AIR
DUST RECYCLE
EMISSION SOURCES
1 CHARGING (FUGITIVE)
2 SLAG TAPPING (FUGITIVE)
3 LEAD TAPPING/CASTING (FUGITIVE)
4 METALLURGICAL (STACK)
Figure 2-3. Typical reverberatory furnace system for secondary lead production.6
-------
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 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.
2-22
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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 inoculation 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. Also, facility
configuration and hot metal travel patterns and distances affect
each emission potential and controllability.
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. Other facilities employ continuous
casting machines. The problems associated with controlling
emissions 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 volatilize from the hot metal surface.
The damp buoyant stream adds to the difficulty of controlling
these sources.7
2.2.6 Estimating Lead Emissions From Process Fugitive Sources
Because lead emission data from process fugitive sources are
scarce relative to process emission data, a technique that can be
2-23
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used to estimate process fugitive emissions is to assume that
they are some fixed percentage of process emissions. The most
recent updates of AP-42 contain corresponding process and process
fugitive emission factors for 22 sources within the ferroalloy
and primary and secondary nonferrous smelting industries.
However, for 10 of these sources (45 percent), the fugitive
emission factor is exactly 5 percent of the process factor. The
basis of these fugitive factors is not always fully documented,
but they are expected to be based on engineering judgement and
are considered to provide only order of magnitude estimates of
limited reliability.
Two of the remaining sources are material processing sources
(crushing and screening operations). For these sources, the
fugitive emission factor is of the same magnitude as the process
emission factor. The remaining 10 sources are high temperature
metallurgical processes such as sintering operations or furnaces.
For sintering operations, results varied widely with process
fugitive emission factors ranging from less than 1 percent to
about 5 percent of the process factor.
Based on this range, the 5 percent estimate that is often
used appears to be a conservative estimate. For furnaces that
are primarily closed (e.g., primary lead blast furnaces and
primary copper reverberatory furnaces) the process fugitive
emission factors were about 0.1 to 1 percent of the process
emission factors. For these sources, a typical emission factor
of 0.5 percent of the uncontrolled process emission factor could
be used to obtain an order-of magnitude estimate in the absence
of other data.
Finally, for furnaces that are potentially open to the
atmosphere for substantial periods during operation or hot metal
transfer (e.g., copper roasters, copper converters, lead smelter
reverberatory furnaces, and open furnaces in ferroalloy plants)
process fugitive emission factors range from 3 to 15 percent of
process emission factors. For such sources, a typical emission
factor of 5 to 10 percent of the process emission factor appears
2-24
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to be appropriate for developing order-of-magnitude emission
estimates.
2.3 REFERENCES FOR CHAPTER 2
1. Fugitive Dust Background Document and Technical Information
Document for Best Available Control Measures,
EPA-450/2-92-004, U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina, September 1992.
2. Muleski, G., and B. Henk (Midwest Research Institute),
Review and Update of Miscellaneous Sources in Chapter 11,
AP-r42, Summary Report, U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina, April 30,
1993.
3. Test Methods for Evaluating Solid Waste, Volume 1A:
Laboratory Manual,.Physical/Chemical Methods, SW-846,
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, November 1986.
4. Compilation of Air Pollutant Emission Factors, Volume I:
Stationary Point and Area Sources, AP-42, U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, September 1993.
5. Muleski, G., T. Cuscino, and C. Cowherd (Midwest Research
Institute), Extended Evaluation of Unpaved Road Dust
Suppressants in the Iron and Steel Industry, Final Report,
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, October 7, 1983.
6. 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.
7. Wallace, D., and C. Cowherd (Midwest Research Institute),
Fugitive Emissions from Iron Foundries, EPA-600/7-79-195,
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, August 1979.
8. Cowherd, C., G. E. Muleski, and J. S. Kinsey (Midwest
Research Institute), Control of Open Fugitive Dust Sources,
EPA-450/3-88-008, U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina, September 1988.
2-25
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3.0 CONTROL OF FUGITIVE EMISSIONS
This section describes measures used to control fugitive
emissions from industrial sources. First, general fugitive dust
emission controls are described. A general description of
process fugitive emission control measures is then presented.
3.1 FUGITIVE DUST EMISSION CONTROLS
The major sources of lead fugitive dust emissions from the
source categories considered in this document are vehicular
traffic on industrial paved roads and other paved plant areas,
vehicular traffic on unpaved plant roads and open areas around
the plant used for transport, and dust generated from materials
handling and wind erosion related to raw material and waste
storage piles. For each of these three types of sources the
principal mechanism by which lead emissions are generated is
mechanical disturbance of lead-bearing material on the surface of
the emitting source. The techniques used to reduce emissions via
this mechanism can be classified into one of two broad
categories: preventive and mitigative. Preventive measures
reduce emissions by either preventing lead-bearing material from
being deposited on the surface or by eliminating or inhibiting
the effect of the mechanical disturbance on the lead-bearing
surface material. Mitigative measures are designed to either
remove or stabilize the lead-bearing material before it can be
emitted.
In evaluating the potential performance of these control
measures for lead emissions in comparison to their performance
for TSP or PM-10 emission, a key distinction must be made for
different types of measures. For preventive measures designed to
eliminate or reduce the quantity of material deposited onto the
3-1
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surface, only the reduction of lead-bearing material is of
interest. Because different control strategies may have
different effects on total surface loading and lead surface
loading, different control efficiencies are expected for lead
emissions and TSP or PM-10 emissions. However, preventive
measures designed to inhibit the effect of mechanical
disturbances and mitigative techniques are expected to have
similar effects on all surface materials. Consequently for these
techniques, performance relative to lead emissions can reasonably
be assumed to be equivalent to TSP or PM-10 performance. This
assumption is used throughout the discussion below.
The remainder of this subsection is divided into three
subsections that address industrial paved roads, unpaved roads or
traffic surfaces, and storage piles, respectively. Within each
section, the applicable fugitive dust mitigation techniques are
identified, and the applicability of these techniques to lead
emissions control are discussed. Finally, procedures for
estimating the effectiveness of the control measures are
described. The primary sources of information for the material
presented in this section on fugitive dust emissions are the EPA
publications Fugitive Dust Background Document and Technical
Information Document for Best Available Control Measures, and
Compilation of Air Pollutant Emission Factors. Volume I;
Stationary Point and Area Sources. The reader should consult
those two publications for the most current information on
fugitive dust emission sources, estimation, and control.
3.1.1 Paved Road Control Measures1
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.
3.1.1.1 Preventive Measures. . As the name implies,
preventive control measures prevent the deposit of additional
materials on a paved surface area. Preventive measures can have
a significant impact on fugitive dust emissions. Mud and dirt
3-2
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carryout from unpaved areas such as parking lots and storage
piles often accounts for a substantial fraction of paved road
silt loadings in many industrial facilities. If ores or waste
materials such as slag or control device catch have a substantial
lead fraction, carryout from areas used to dispose or store these
materials can contribute to silt lead loadings.
TABLE 3-1.
INDUSTRIAL PAVED ROAD DUST DEPOSITION MECHANISMS
AND PREVENTIVE CONTROLS3
Mechanism for road deposition
— Spills from haul trucks, front end
loaders, and other vehicles
— Vehicle entrainment from unpaved
adjacent areas
— Entrainment from stormwater
washing eroded surface material
from open areas in plant onto paved
travel surfaces
~ Wind erosion from adjacent areas
— Stack and fugitive emission sources
Controls
— Require trucks to be covered
— . Require freeboard between load and top of hopper
— Wet material being hauled
— Rail/conveyor/crane transport
— Pave/stabilize portion of unpaved areas nearest to paved road
— Rail/conveyor/crane transport
— Improve storm water control
— Vegetative stabilization
— Rapid cleanup after event
— Wind breaks
— Vegetative stabilization or chemical sealing of ground
— Pave/treat/curb parking areas, driveways, shoulders
— Limit traffic or other use that disturbs soil surface
— Stack emission controls
— Fugitive emission controls
aReference 1.
Table 3-1 lists some of the more commonly used preventive
measures for controlling fugitive dust emissions from paved
roads. The control measures presented in Table 3-1 are grouped
according to the mechanism by which material is deposited on the
paved road. These mechanisms for road deposition include
material spills from haul trucks; carryout and entrainment of
dust from nearby construction activities; dust entrained by
traffic in nearby unpaved areas; sedimentation from stormwater
runoff; and wind erosion from adjacent areas. In the vicinity of
3-3
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industrial sources that emit significant quantities of lead or
that process materials with significant lead contents, it is
likely that lead will be present on road surfaces and in the
surrounding soil. With respect to fugitive lead emissions, the
mechanisms for road deposition are of concern only if the
deposited material contains lead.
Of course, deposition from emission sources can be prevented
or reduced using emission source controls. The control measures
used to prevent the deposition of material onto paved roads from
the other mechanisms for deposition include stabilizing adjacent
areas, controlling potential spill and carryout materials, and
traffic control. These controls are described in the following
paragraphs.
Data on the control efficiencies are unavailable for many of
the preventive measures described below. The efficiency is
assumed to be directly related to the reduction in lead silt
loading on the paved surface. If a facility chooses to implement
some combination of these techniques as a part of a lead control
plan, road dust sampling before and after implementation of the
preventive measures is recommended. Equation 2-2 can then be
used to estimate control efficiencies. In designing and
evaluating such control programs, particular attention should be
paid to the temporal and spatial distribution of both the control
measure and the emitting sources so that both controls and
measurements are associated with the industrial paved road
segments with the greatest emitting potential.
3.1.1.1.1 Stabilizing adjacent areas. This category of
preventive measure includes chemical sealing, establishing
vegetative covers, erecting wind breaks, rapid cleanup of spills
on adjacent areas, and improving stormwater control.
3.1.1.1.2 Controlling spill and carryout materials. This
category of preventive measures includes covering trucks that
haul lead-containing materials, increasing the freeboard in haul
truck hoppers carrying lead-containing materials, wetting any
lead-containing materials being hauled, cleaning vehicles before
3-4
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they enter the road, and paving or stabilizing access roads from
unpaved areas where lead contamination of the soil is likely.
One of the major sources of dust loading on industrial paved
roads is spillage of materials from either raw material or waste
material haul trucks. Spillage can be reduced by either
maintaining adequate freeboard between the top of the material
being transported and the top of the truck or hopper or covering
the bed. These techniques prevent both spillage by bounce out
over the top of the bed and wind erosion from the material
surface. An alternative is to wet the material prior to
transporting it. However, this technique must be applied
cautiously because excessive watering can result in runoff of
liquid that includes suspended lead-bearing solids during
transport. No substantive data are available on the performance
of these techniques to reduce spillage. If a facility chooses to
implement this technique, road dust sampling before and after
implementation is recommended. Equation 2-2 can then be used to
estimate control efficiencies.
Emissions due to carryout from unpaved areas can be
estimated using the following relationship:
Epb = 29 (Ls) (N) for N <25 and (3-1)
Epb = 68 (Ls) (N) for N >25
where:
Epb = unit increase in lead TSP emissions in g/vehicle;
N = number of vehicles entering from the unpaved area;
Ls = lead content of surface material in unpaved area as a
weight fraction.
The product of E, Ls, and the number of daily vehicle passes on
the paved road provides the daily emission reduction from vehicle
carryout assuming complete prevention. This equation also
assumes that the same mechanisms that result in TSP control also
result in lead control.
The level of fugitive dust emitted by an industrial facility
depends to a large degree on the methods of transporting
materials to, from, and within plant boundaries. Some facilities
3-5
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rely extensively on rail to transport materials. In such cases,
fugitive dust emissions from traffic are likely to be less of a
problem for several reasons. 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.
The use of conveyors and cranes to move materials within the
plant boundaries also reduces the volume of road traffic, thereby
preventing emissions from road traffic.
3.1.1.1.3 Controlling traffic. This measure entails
limiting traffic from adjacent unpaved roads or adjacent areas
where lead contamination of the soil is likely. Data are scarce
on emissions reductions that result from these preventive
measures. Thus, it is difficult to estimate their control
effectiveness. If such a strategy is used, measurements of road
lead loading before and after implementation of the strategy are
recommended in order to estimate control effectiveness.
3.1.1.2 Miticrative Measures. The most commonly used
mitigative measures for controlling fugitive dust emissions from
paved roads include broom sweeping, vacuum sweeping, and water
flushing. Table .3-2 summarizes the estimated control
efficiencies for these control measures, which are discussed in
the following paragraphs.
3.1.1.2.1 Broom sweeping. 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, thus broom sweeping may
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TABLE 3-2.
MEASURED EFFICIENCY VALUES FOR PAVED
ROAD CONTROLS3
Method
Broom sweeping
Vacuum sweeping
Water flushing
Water flushing followed by
sweeping
Cited efficiency
25-30 percent
0-58 percent
46 percent
34 percent
69-0.231 Vc'd
96-0.263 Vc'd
Comments
Maximum efficiency for initial sweeping;
efficiency decreases for subsequent sweeping
Field emission measurement (PM-15),
12,000-ft3/min blowerb
Based on field measurement of 30 fim
Average of available data
Field measurement of PM-15 emissions^
Field measurement of PM-15 emissions'5
aReference 1. All results based on measurements of air
emissions from industrial paved roads.
bCan be assumed to be a conservative estimate of TSP control
efficiency. The PM-10 control efficiency can be assumed to
be the same as that tested.
cWater applied at 0.48 gal/yd2.
^Equation yields efficiency in percent, V = number of vehicle
passes since application.
not be very effective as a control of fugitive dust emissions.
Measurement-based control efficiency for industrial roads
(Table 3-2) indicates a maximum (initial) instantaneous control
of roughly 25 to 30 percent can be achieved.
3.1.1.2.2 Vacuum sweeping. 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 pass 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.
Available instantaneous control efficiency data are
inconsistent but indicate efficiencies up to 58 percent. An
average of the available data indicates an efficiency of
34 percent.
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3.1.1.2.3 Water flushing. 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 fugitive dust
emissions.
Equations to estimate instantaneous control efficiency
values are given in Table 3-2. Note that water flushing and
flushing followed by broom sweeping represent the two most
effective control methods described here.
3.1.2 Unpaved Road Control Measures
Measures for controlling fugitive dust emissions from
unpaved travel surfaces are listed in Table 3-3. Preventive
measures, which also are referred to as source extent reductions,
either 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 2-4. Mitigative measures
can be categorized as surface improvements and surface
treatments. Surface 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 techniques that require periodic reapplications and
can be categorized as (l) 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 2-4) uncontrolled emission levels are required.
Estimates of control efficiency for lead emission were developed
under the assumption that reductions for lead are equivalent to
those for PM-10 or TSP. This assumption is reasonable in that
3-8
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the same basic control mechanisms apply to lead-bearing particles
as apply to general surface dust.
TABLE 3-3. CONTROL TECHNIQUES FOR UNPAVED TRAVEL SURFACES
a
Type of control
Specific control measures
Preventive (source extent
reductions)
Speed reduction
Traffic reduction
• Banning vehicles
• Limiting vehicle access
• Rail/conveyor/crane
transport
Mitigative
Surface improvement
• Paving
• Gravel surface
Surface treatment
• Wet suppression
• Chemical stabilization
Reference 1.
3.1.2.1 Preventive Measures. Preventive measures for
controlling unpaved road fugitive dust emissions include speed
reduction and traffic reduction. 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 4). For example, because emissions are proportional to
vehicle speed, reducing vehicle speed by 25 percent results in a
corresponding 25 percent reduction in fugitive dust emissions.
As discussed in Section 3.1.1.1.2, the use of rail, conveyors,
and cranes to transport materials prevent the entrainment of
fugitive dust by reducing traffic volume.
3.1.2.2 Mitigative Measures. Mitigative measures for
controlling fugitive dust emissions from unpaved roads include
surface improvements and surface treatment. Surface treatment
methods include wet suppression and chemical stabilization.
3.1.2.2.1 Surface improvements. These control measures
consist of either paving or replacing aggregate with one of lower
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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 3.1.1 on paved
road control techniques. Aggregate replacement reduces total
suspended particulate emissions by reducing the silt content of
the road surface. However, this control measure has little
effect on fugitive lead emissions because lead particles are
deposited on the road by other sources as described in the
discussion of paved road emissions.
3.1.2.2.2 Wet suppression. Watering, or wet suppression,
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 (1) the
amount of water applied per unit area of road surface, (2) the
time between reapplications, (3) traffic volume during that
period, and (4) 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. Figure 3-1 can be used to estimate the control
efficiency of wet suppressions.
An empirical model for the performance of watering as a
control technique is as follows:
(3-2)
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/m2) ;
and
t = time between applications, hr.
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100%
o
z
LU
O
U_
LL
UJ
_l
O
OC
o
o
Q_
O
LU
1
75%
50% -
95%
25%
RATIO OF CONTROLLED TO UNCONTROLLED
SURFACE MOISTURE CONTENTS
Figure 3-1.
Watering control effectiveness for unpaved travel
surfaces.^
3-11
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Figure 3-2. Pending
3-12
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Estimates of the potential average hourly daytime evaporation
rate may be obtained from
0.0049 x (value-in Figure 2-1) for annual conditions, or (3-3)
P =
0.0065 x (value in Figure 2-1) for summer conditions
3.1.2.2.3 Chemical stabilization. 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 petroleum-based chemical dust suppressants use can
be estimated using Figure 3-2. The data used to develop the
curves in Figure 3-2 are based on measurements of PM-10
emissions. However, the figure can be used to drive a
conservative estimate of TSP emission control efficiency. For
example, if 0.25 L/m2 (0.055 gal/yd2) of chemical concentrate is
applied at 1 month intervals, after 3 months the ground inventory
is 0.75 L/m2 (0.17 gal/yd2). This corresponds (in Figure 3-2) 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
3-13
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100
0
0.05 0.1 0.15 0.2 0.25
GROUND INVENTORY (gal/sq yd)
0.3
Figure 3-3
Petroleum-based chemical dust suppressant control
efficiency model.1
3-14
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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.
3.1.3 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. Preventive
and mitigative measures for controlling fugitive dust emissions
from both of these categories of materials handling operations
are summarized in Table 3-4. The efficiency of these controls
ties back to the emission factor relationships presented earlier
in Section 2.1.3. Control efficiencies were calculated with the
assumption that lead control efficiency is equivalent to TSP or
PM-10 control efficiency. Because the control mechanisms are
comparable for these pollutants, this assumption appears to be
reasonable.
3.1.3.1 Preventive Measures. Preventive measures for
controlling fugitive dust emissions from storage piles can be
further classified as source extent reductions and source
improvements.
Source extent reduction measures are largely a function of
work practices and include reducing the area of materials
disturbed, reducing the frequency of disturbances, and promptly
cleaning up spills. This type of control measure can be applied
without the need to invest in a control program. Source
improvements include enclosing, drop height reduction, wind
sheltering, moisture retention, spillage reduction and using
choke-feed or telescopic chutes to confine the material being
transferred. Many of these measures also can be applied through
good work practices and are not discussed further in this report.
Enclosures are discussed in detail in the following paragraphs.
3.1.3.1.1 Enclosures. Enclosures are an effective means of
controlling fugitive dust emissions. Enclosures can either fully
or partially enclose the source. Enclosures traditionally used
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TABLE 3-4. CONTROL TECHNIQUES FOR STORAGE PILES
Type of control
Specific control measures
Material handling
Preventive
Mitigative
Source extent reductions
• Mass transfer reduction
• Reduction in frequency of
material handling
• Prompt cleanup of spills
Source improvement
Enclosing
Drop height reduction
Wind sheltering
Moisture retention
Spillage reduction
Use of choke-feed or
telescopic chutes
Surface treatment
• Wet suppression
Wind erosion
Preventive
Mitigative
• Disturbed area reduction
• Disturbance frequency
reduction
• Spillage cleanup
Source improvement
• Spillage reduction
• Disturbed area exposure
(wind) reduction
Surface treatment
• Wet suppression
• Chemical stabilization
References 1 and 2,
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for fugitive dust: emissions control include three-sided bunkers
for storing bulk materials, storage silos for various types of
aggregate materials, open-ended buildings, and similar
structures. Drive-through enclosures for delivery trucks and
rail cars also are very effective in reducing fugitive dust
emissions, particularly if the enclosure is exhausted to a PM
emission control device. 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 dust emissions. The only available data on fugitive
dust emission reductions from enclosures are for windbreaks.
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). One study of a
windbreak with 50 percent porosity, windbreak height equal to the
storage pile height, and windbreak width equal to the storage
pile base indicated a 50 to 70 percent area-averaged wind speed
reduction. Other data on the control efficiency of windbreaks
are summarized in Table 3-5.
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.
3.1.3.2 Mitiaative Measures. Mitigative measures for
controlling fugitive dust emissions from storage piles include
chemical stabilization and wet suppression. These measures are
described in the following paragraphs.
3.1.3.2.1 Chemical stabilization. Petroleum resins and
latex binders 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
3-17
-------
TABLE 3-5. SUMMARY OF AVAILABLE CONTROL EFFICIENCY DATA
FOR WIND FENCES/BARRIERS3
Material or control
parameter
Type of fence/barrier
Porosity of fence/barrier
Height/ length of
fence/barrier
Type of erodible material
Material characteristics
Incident wind speed
Lee-side wind speed
Particulate measurement
technique11
Measured particulate
control efficiency0
(Larson, 1982)
Textile fabric
50 percent
1.8 m/50 m
Fly ash
Percent H2O = 1.6
Percent <50 pm = 14.7
Percent <45 pm = 4.6
Average (no screen) =
4.3 m/sec (9.7 mph)
Average (upwind) =
5.32 m/sec (11.9 mph)
Average = 2 m/sec (4.0
mph)
or 64 percent reduction
U/D = hi-vol and hi-vol
w/SSI (11 tests)
TP = 64 percent (average)
TSP = 0 percent (average)
(Radkey and MacCready,
1980)
Wood cyclone fence
50 percent
3 m/12 m
Mixture of topsoil and
coal
Unknown
maximum 27 m/sec (60 mph)
Unknown
U/D - Bagnold catchers
(one test)
TP = 88 percent (average)
I
M
00
aReference 1.
bHi-vol = high volume air sampler; hi-vol w/SSI = high volume air sampler with 15
/mA size-selective inlet, SSI.
CTP = total particulate matter, TSP = total suspended particulate matter
(particles <30/xmA) . Because most lead emissions are expected to be in the TSP,
lead efficiency is assumed equal to TSP efficiency.
-------
resin of an undisturbed steam coal pile (applied 60 days prior to
testing) indicated a TSP control of 89.6 percent.
3.1.3.2.2 Wet suppression. 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 surfactant. Surfactants, or surface active
agents, reduce 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 systems are more costly
and require extra materials and equipment. Foam systems also
achieve control primarily through the wetting and agglomeration
of fine particles.
The available data indicate a wide range of efficiencies
from the use of wet suppression for controlling fugitive dust
emissions from storage piles and material handling operations.
For conveyor transfer points, measured control efficiencies range
from 42 to 75 for liquid sprays and from 0 to 92 percent for foam
systems. In addition, the data indicate that for some
operations, foam systems do not achieve any measurable level of
control until a threshold application rate is reached. In
addition, the data indicate that control efficiencies for foam
application decrease with increasing material temperature.
3-19
-------
3.2 PROCESS FUGITIVE EMISSION 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. However, both the
selection of the system and the ultimate performance of the
system are related to industry- and facility-specific design and
operating characteristics.
3.2.1 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 that 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, and these factors can affect performance as well as
design. 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.
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
3-20
-------
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 3-4 through 3-6 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 3-4 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 3-7. Figure 3-8
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, hooding for both systems must be designed
in such a way that it interferes with neither operation.
Figure 3-9 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 the exhaust
3-21
-------
15
SKIP HOIST FURNACE
CHARGING HOODS
(T9ANDT10)
EXHAUST PICKUPS
FOR SKIP HOIST
LOADING HOOD
SLOT HOOD OVER ACCESS
DOORS TO FURNACE
SLAG
TAPPING
HOOD
METAL
TAPPING
HOOD
TO
BAGHOUSE
-LAUNDER
HOOD
REFINING KETTLE
HOODS
MOLD
FILLING
HOOD
EXHAUST PICKUPS FOR
NEW KETTLE HOODS
Figure 3-4. Overview of modified local exhaust ventilation
.system. 3
3-22
-------
TOT, 2
SLAG TAPPING HOOD
FRONT SURFACE
OF HOOD RAISED
USING CABLE AND
PULLEY SYSTEM
METAL DUCT
DIAMETER = 38 cm (15"
SWING AWAY
SIDE PANEL
SLAG
CONTAINER
Figure 3-5. Blast furnace slag tapping hood.3
3-23
-------
SKIP HOIST
ENCLOSURE
EXHAUST DUCTS
TO TOP OF BLAST
FURNACE
NEW RAW
MATERIALS
CONFINEMENT
STEEL PLATE
BARRIER
FLUE DUST AND
AGGLOMERATED
FLUE DUST
LIMESTONE CHIPS
Figure 3-6. Skip hoist ground level loading station.3
3-24
-------
BLAST GATE
OPEN
BACK
FACE VELOCITY
AT BACK OF HOOD
v, = 0.75- 1.8 nVs
(ISO • 350 tt/min)
COOLING
WATER RESERVOIR
BLAST FURNACE BLOCK CASTING HOOD
BLAST GATE
FACE VELOCITY, Vf = 2.6 - 4.1 m/s
(300-800tt/min)
BLAST FURNACE LAUNDER HOOD
Figure 3-7.
Alternate suggested design concept for blast furnace
launder and block casting hoods.4
3-25
-------
CJ
I
to
en
EXHAUST TO BAGHOUSE
BUTTERFLY DAMPER
HINGED LAUNDER
ACCESS DOOR
ROLLING FRONT TOP
ACCESS DOORS
DESIGN CHARACTERISTICS
ENCLOSURE TO PROVIDE
CAPTURE VELOCITIES AT OPENING
OF 350 - 500 FT/MIN
TRANSPORT VELOCITY IN DUCTS:
£ 4.000 FT/MIN
FURNACE
CRUCIBLE-
ROLLING SIDE
ACCESS DOORS
LEAD MOLD-
MAY BE WATER
COOLED
HINGED METAL ACCESS DOORS TO
PROVIDE FULL ACCESS TO FRONT OF
ENCLOSURE
EXAMPLES OF FEASIBLE
ENGINEERING CONTROLS
ENCLOSURE HOODING--BLAST
FURNACE LEAD TAP CONTROLS
Figure 3-8
Suggested design concept for blast furnace lead tapping hood system
(lead tap, launder, and block casting.4
-------
RETRACTABLE ARCH
HOOD ENCLOSURES
ELECTRICALLY
OPERATED
DAMPER
FINISHED
METAL LADLE
BRICK FLUE
HOOD ENCLOSING
FURNACE TO FLUE
CONNECTION
WIDE SLOT EXHAUST
PICKUPS
168 cm (5 ft 6 in.)
Figure 3-9. Rotary furnace charging and tapping controls.5
3-27
-------
ventilated. An arched hood is provided over the charging/tapping
end of the furnace. Exhaust draft to this hood is controlled by
an electrically operated damper. The damper is 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
fume emissions 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 3-10. Note the chains
around the base of the hood that are used to provide an airflow
barrier without threatening the structural integrity of the hood.
3.2.2 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. 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
forklifts and other equipment into and out of the building.
3-28
-------
U)
I
to
vo
DUCT FINS FOR
STRUCTURAL
SUPPORT OF HOOI
SWIVEL BEARII
INSIDE DIAMETER
19.7 cm (7.75 in.
EXPANSION \ DAMPER
TAKEOFF
FLANGE
FINISHED
METAL LADLE
HOOD ENTRY COEFFICIENT
Ce o 0.58
AIR FLOW MEASUREMENTS
vface (AT CHAINS) - 0.51 -1.3 mps (100 - 250 ll/min)
Vslot -5-1-10 mps (1,000 - 2,000 ft/min)
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 3-10. Finished metal ladle cooling hood.5
-------
3.2.3 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 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 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.
3.3 REFERENCES FOR CHAPTER 3
1. Fugitive Dust Background Document and Technical information
Document for Best Available Control Measures,
EPA-450/2-92-004, U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina, September 1992.
2. Technical Guidance For Control of Industrial Process Fugitive
Particulate Emissions, EPA-450/3-77-010, Prepared by PEDCo
Environmental, Inc. for U. S. Environmental Protection
Agency, March 1977.
3. Coleman, R., Jr., and R. Vandervort. Demonstration of
Fugitive Emission Controls at a Secondary Lead Smelter, In:
Lead-Zinc-Tin 1980, J. M. Cigan, T. S. Mackey, and
T. J. O'Keefe (eds.), Proceedings of TMS-AIME World Symposium
on Metallurgy and Environmental Control. Las Vegas, Nevada,
February 24-28, 1980.
4. 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.
5. Burton, D. J., R. T. Coleman, W. M. Coltharp, J. R. Hoover,
and R. Vandercort (Radian), Control Technology Assessment:
The Secondary Nonferrous Smelting Industry, NIOSH Contract
No. 200-77-0008, Prepared for the U.S. Department of Health
and Human Services, Cincinnati, Ohio, October 1980.
6. 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.
3-30
-------
4.0 PRIMARY LEAD SMELTING
4.1 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. Concentrating the ore is a preliminary step and is not
considered part of the actual smelting process. Primary lead
smelting includes four major steps: sintering, reduction,
dressing, and refining.1 Figure 4-1 shows a process flow diagram
for a typical primary lead smelter.
4.1.1 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.2 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 4-2
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, fed into a crushing machine, and then are
moistened and pelletized. These materials are then split into an
4-1
-------
(CONCENTRATE^-*-
I
to
— LIMESTONE
— SILICA
t_ SINTER RECYCLE
- FLUE DUST
-COKE
- LIMESTONE
- SILICA
.SLAG
-PbO
-COKE
COKE
NH4CL
. SODA ASH
. SULFUR
. FLUE DUST
.COKE
LIMESTONE
- SILICA
- SODA ASH
- SULFUR
- PIG IRON
pPbO
-COKE
Figure 4-1. Typical primary lead processing scheme.1
-------
STRONG GAS
TO DEDUSTING
> k
FEED
IGNITION
FURNACE
RECIRCULATING STREAM
FRESH AIR
FRESH AIR
SINTER
Figure 4-2. Updraft sintering with weak gas recirculation.'
4-3
-------
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 is crushed
and screened. The oversize 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.4-5
4.1.2 Reduction
Sinter is reduced to lead bullion in a blast furnace, which
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.
4-4
-------
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.
4.1.3 Drossina
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 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.1
4.1.4 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.1
4.2 FUGITIVE EMISSION SOURCES
A summary of potential fugitive emissions sources for
primary lead smelters is provided in Table 4-1. 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 fugitive dust emissions include paved and unpaved
roads. The most significant process fugitive sources are
sintering and furnace (blast and reverberatory) leakage and
4-5
-------
TABLE 4-1. 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
aReference 6.
4-6
-------
tapping.2 Lead pouring and transfer in the dressing operation
may also be a significant source of process fugitive emissions at
some facilities.
4.2.1 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 fugitive dust emissions
from paved roads, unpaved roads and selected storage piles at two
primary lead smelters are summarized in Table 4-2.
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. As explained in Section 3.1, the use of
rail transport significantly reduces the potential for fugitive
dust emissions from vehicular traffic.
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, however.7-8
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
4-7
-------
TABLE 4-2. ESTIMATED FUGITIVE DUST EMISSIONS AT TWO
PRIMARY LEAD SMELTERS3
Plant
A
Emission source''
Paved road 1
Paved road 2
Paved road 3
Paved road total
Unpaved road 1
Unpaved road 2
Unpaved road total
Ore concentrated pile
Baghouse dust 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
ton/yr
7.89
0.088
0.099
8.08
1.90
0.62
2.51
0.42
0.011
0.43
11.02
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
ton/yr
5.52
0.022
0.066
5.61
0.32
0.011
0.33
0.32
0.011
0.33
6.27
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
7.97
0.25
0.34
8.56
0.31
3.34
3.65
0.08
1.21
1.29
13.50
8.79
0.28
0.38
9.44
0.34
3.68
4.02
0.088
1.33
1.42
14.88
5.41
0.07
0.10
5.58
0.17
0.25
0.42
0.06
0.73
0.79
6.79
5.96
0.077
0.11
6.15
0.19
0.28
0.46
0.066
0.81
0.87
7.49
aReferences 7,8.
bonly the major fugitive dust sources are listed. Other sources
exist, but are assumed to be negligible.
4-8
-------
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 3 percent) is likewise of sufficient
magnitude to prevent significant lead fugitive dust emissions.
4.2.1.1 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.
However, representative values for surface loading, silt content,
and lead content must be determined from road surface material
samples. Likewise, emissions from materials handling operations
depend upon the moisture content and wind speed. Table 4-3
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 (155 to 2,644 Ib/mi). 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.
4-9
-------
TABLE 4-3. TRAFFIC AND ROAD DUST DATA FROM TWO PRIMARY LEAD SMELTERS3
Type of traffic
Road
length, km
Daily
vehicle
passes
Average
speed,
krn/hr
Average
No. of
lanes
No. of
wheels
Vehicle
weight,
mg
Surface
loading,
kg/km
Silt
content,
weight
percent
Lead
content
of silt,
weight
percent
Plant A
Paved road 1
Paved road 2
Paved road 3
Unpaved road 1
Unpaved road 2
Ore concentrate transport
Lead product transport
Slag transport
Slag transport
Slag transport
0.417
0.094
0.082
0.330
0.249
21.7
16.7
3.33
9.05
5.72
8.05
8.05
8.05
8.05
8.05
2
2
2
2
2
18
18
18
18
18
41.7
34.5
34.5
34.5
34.5
747
50.7
110
27.9
33.5
90.4
8.59
6.58
69.95
21.51
60.93
16.62
0.95
PlantB
Paved road 1
Paved road 2
Paved road 3
Unpaved road 1
Unpaved road 2
Ore concentrate transport
Lead product transport
Miscellaneous traffic
Ore concentrate transport
Lead product transport
0.117
0.043
0.133
0.023
0.246
44
16
29
16
44
8.05
8.05
8.05
8.05
8.05
2
2
2
2
2
18
18
18
18
18
34.5
41.7
20.5
41.7
34.5
568
251
43.7
81.7
39.4
87.6
12.2
5.11
67.87
27.36
29.55
56.30
7.61
I
I-1
o
aReferences 7 and 8.
-------
Estimating process fugitive lead emissions requires data on
lead content in addition to emission factors. Lead content by
TABLE 4-4. LEAD CONTENT
THREE PRIMARY
OF FUGITIVE EMISSIONS AT
LEAD SMELTERS*
Source
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
Lead, weight percent
Plant A
37
19
58
31
47
38
3
Plant B
47
35
51
Plant C
10
12
22
9
10
aReference 2.
weight percent for a number of process fugitive emissions sources
at three primary lead smelters is presented in Table 4-4.
4.2.2 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
4-11
-------
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.4 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.
4.3 ESTIMATING FUGITIVE EMISSIONS
4.3.1 ' Fugitive Dust Emission Estimation
As discussed in Section 4.2, the major sources of fugitive
dust 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. Lead fugitive dust emissions
can be estimated using Equations 2-2, 2-4, 2-6, and 2-8 presented
in Section 2.0 for paved roads, unpaved 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
4-12
-------
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 4-3 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 4-3, surface dust loading ranged from 43.7 kg/km to
747 kg/km (155 to 2,644 Ib/mi). 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 to 90.4 percent and averaged 60.0 percent for paved roads;
for unpaved roads, it varied from 5.11 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 4-3 includes data for
these parameters for two primary lead smelters.
The only potentially significant fugitive dust source of
lead emissions, other than roads, is the loading and unloading of
the ore concentrate storage pile. Table 4-5 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 2-6 because much of the entrained particulates would
settle in the building without being emitted to the outside
environment.
4.3.2 Process Fugitive Emission 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 4-6 summarizes the process emission
4-13
-------
TABLE 4-5. MOISTURE, SILT, AND LEAD CONTENT OF STORAGE PILE
MATERIALS AT TWO PRIMARY LEAD SMELTERSa
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
aReferences 7 and 8.
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.
TABLE 4-6.
PROCESS FUGITIVE EMISSION FACTORS FOR PRIMARY
LEAD SMELTING
Process
Sintering
Blast furnace
Reverberatory furnace
Dross kettle
Lead emission
factor,
kg/Mg (Ib/ton)
0.10a
(0.20)
0.12
(0.24)b
0.24
(0.48)c
0.18
(0.36)d
Emission
factor rating
D
D
D
D
aReference 1, for entire sinter building.
^Reference 1, includes charging, tapping, and leakage.
°Reference 1, includes charging, tapping, and leakage.
^Reference 1.
Because of this low rating, these emission factors produce order
of magnitude estimates only and thus should be used with caution,
4-14.
-------
particularly when they are used to estimate fugitive lead
emissions from a specific facility.
4.4 FUGITIVE EMISSION CONTROLS
The following paragraphs describe the measures used to
control fugitive emissions at primary lead smelters. Fugitive
dust emission controls are first presented. Process fugitive
emission controls are then discussed.
4.4.1 Fugitive Dust Emission Controls7-8
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 3.1.1.4, 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 to limit dust
reentrainment. At one plant, trucks are unloaded in a
ventilated, enclosed area to minimize fugitive dust emissions.5
4.4.2 Process Fugitive Emission Controls
4-15
-------
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 4-7 lists some of the
process fugitive emission controls in use at primary lead
smelters. The most important of these are described below.
4.4.2.1 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.
4.4.2.2 Blast/Reverberatory Furnace Fugitive Emission.4>i
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.
4-16
-------
TABLE 4-7. • SPECIFIC PROCESS FUGITIVE LEAD EMISSION
SOURCES AND POTENTIAL CONTROLS AT PRIMARY LEAD SMELTERSa
Emission source
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Ore concentrate unloading
Feed end of sinter machine
Belt conveyors in sinter plant
Sinter machine leakage
Blast furnace leakage
Blast furnace tapping
Lead ladle pouring and change
over
Kettle dressing
Refining
Miscellaneous
Potential control
• Wash down transport trucks
• Sweep and/or wet down roads and ramps
• Unload trucks in enclosed ventilated buildings
• Improve seals 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 granulator
• Hood and ventilate ladle during pour
• Increase hood airflow
• Cover ladle totally 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
• Cover kettle partially
• Use continuous dressing^
• Cool lead pot to reduce fume generation
• "Hide" dressing
• Hood and vent kettle during transfer, heat and casting
• enclose and ventilate process buildings completely''
• Wash down building interior at regular intervals
aReferences 4 and 5.
in use at domestic primary lead smelters.
4-17
-------
Fugitive emissions from pouring lead from the ladle can be
reduced by a number of measures. The ladle can be hooded and
ventilated during pouring, and a mobile hood can be used during
changeover. Another proposed control measure is to pump lead
directly to the dross kettles using an electromagnetic 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.9
4.4.2.3 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.9
4.5 REFERENCES FOR CHAPTER 4
1. Compilation of Air Pollutant Emission Factors, Volume I:
Stationary Point and Area Sources, AP-42, U. S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
September 1993.
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.
3. Background Information for New Source Performance Standards:
Primary Copper, Zinc, and Lead Smelters, Volume I: Proposed
Standards, EPA-450/2-74-002a, U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina, October 1974.
4-18
-------
4. Evaluation of Lead Emission Controls at the Doe Run Company's
Primary Lead Smelter at Heculaneum, Missouri, Fluor Daniel,
Inc., Redwood City, California, July 17, 1989.
5. Emmel, B., and A. J. Miles (Radian), Evaluation of Lead
Emission Controls at ASARCO's Primary Lead Smelter at Glover,
Missouri, Contract No. 68-02-3513, WA 58, and No. 68-02-3881,
WAO1, prepared for U. S. Environmental Protection Agency,
Region VII, Kansas City, Missouri, March 22, 1985.
6. Technical Guidance for Control of Industrial Process Fugitive
Particulate Emissions, EPA-450/3-77-010, U. S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
March 1977.
7. Memorandum from Vaught, C. (Midwest Research Institute), to
Scott, D., U. S. Environmental Protection Agency, Air Quality
Management Division, Research Triangle Park, North Carolina,
September 21, 1990, Report on August 8, 1990, trip to
Plant A.
8. Memorandum from Vaught, C. (Midwest Research Institute), to
Scott, D., U. S. Environmental Protection Agency, Air Quality
Management Division, Research Triangle Park, North Carolina,
September 21, 1990, Report on August 9, 1990, trip to
Plant B.
9. Smith, R. D., O. 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.
4-19
-------
5.0 SECONDARY LEAD SMELTING
5.1 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 ai variety of miscellaneous
items such as ammunition, pigment, solder, boat keels, and
fabricated products.'
Currently, approximately 20 secondary lead smelters are
operating or are under construction in the United States.2 Each
of these facilities differs with respect to process configuration
and consequently with respect to fugitive emission sources.
Major factors that affect these configurations are scrap source,
intermediate and final products, and type of smelting furnace.
Table 5-1 identifies the secondary lead facilities currently in
operation 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 5-1 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.
5-1
-------
TABLE 5-1. SECONDARY LEAD SMELTING OPERATIONS IN THE U.S.
Plant name
Delatte Metalsc
Doe Run Company''
Exide Corp.0
East Penn Manu-
facturing Company,
Inc.6
Exide Corp.
General Smelting and
Refining Company
GNB, Inc.f
GNB, Inc.i
GNB, Inc.
Gopher Smelting and
Refining Company
Gulf Coast Recycling,
Inc.c
Master Metals
Refined Metals Corp.
Refined Metals Corp.
Ross Metals
RSR Corp.
RSR Corp.
RSR Corp.
Sanders Lead
Schuylkill Metals'
Schuylkill Metals
Tejas Resources, IncJ
Location
Ponchatoula, LA
Boss, MO
Muncie, IN
Lyons Station, PA
Reading, PA
College Grove, TN
Frisco, TX
Vemon, CA
Columbus, GA
Eagan, MN
Tampa, Fla.
Cleveland, OH
Beach Grove, IN
Memphis, TN
Rossville, TN
Indianapolis, IN
City of Industry,
CA
Middletown, NY
Troy, AL
Forest City, MO
Jaton Rouge, LA
Terrell, TX
Blast furnace
No.
1
1
2
1
1
1
2
1
2
1
1
1
1
1
1
1
APCDb
FF
AB/FFAVS
FF/VS
FF
FF/PBS
FF/VS
FF
FF
FF
FF
FF
FF
FF
AB/FFAVS
FF
AB/FF/
WS/ME
Reverb./rotary
No.
1
1
2
1
1
1
lh
1
1
1
1
APCDb
FF
AB\FF\WS
FF/VS
FF/PBS
FF/VS
FF
FF
FF
FF/TS
FF
FF
Kettle furnace
No.
16
9
10
3
10
14
5
5
5
8
7
6
NA
6
7
6
6
5
6
9
APCDb
FF
FF
FF
FF
FF
FF
VS
FF
VS
FF
FF
FF
FF
FF
FF
FF
VS
FF
FF
FF
Reference 1, except where indicated.
bAir pollution control device (APCD): FF = fabric filter; TS
= tray-type scrubber; VS = venturi scrubber; AB =
afterburner; WS = wet scrubber; ME = mist eliminator; PBS =
packed bed scrubber.
^Reference 2.
dReference 3.
^Reference 4.
fReference 5.
^Reference 6.
VRotary furnace.
^•Reference 7.
3Reference 8.
5-2
-------
OXIDES. FLUE
ousr. MIXED
SCHAH
Ul
I
U)
BATTERIE
DROSSES.
RESIDUES.
OVERSIZE
SCRAP
RESIDUES.
DIE SCRAP.
It AD SHEATHED
CABLE AND WIRE
HIGH LEAD
CONTENT
SCRAP
LltCSIONE
RECYCLED DUST
COKE
SLAG RESIDUE
LEAD OXIDES
SCRAP IRON
RERUN SLAG
FUEL
— FLUX
— FUtL
— All OYINH AGENT
— SAWDUSI
Figure 5-1. Typical secondary lead smelting and refining scheme.
10
-------
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
(86 percent by weight in 1992), the discussion below describes
the process when batteries are the primary source of scrap.9
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 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 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.1
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 storage and preparation area. Here,
the lead scrap is combined with other charge materials prior to
being charged to the smelting 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.
5-4
-------
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 5.1.3. 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. Fabric filters or wet scrubbers are
the primary air pollution control devices used to control PM
emissions from smelting furnaces. 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.
5.1.1 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.
5-5
-------
The available information indicates that the handling and
storage practices of these materials varies considerably across
the secondary lead smelting industry. 2"*'n'14 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. Feed hoppers and pan-
or belt-type conveyors often are used in furnace charging. 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.
5.1.2 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 some smelters is flue
dust agglomeration. These processes are reviewed briefly in the
paragraphs below.
5-6
-------
The available literature suggests that battery wrecking
practices vary considerably from plant to plant. However, most
plants use some type of crushing, grinding, or cutting process to
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.15
Battery saws are used to saw off the top of the battery
case. Battery shears also are used to slice off battery case
tops. After the tops are removed, the battery cases are tumbled
to remove the battery plates.2 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.
Some facilities chemically remove sulfur from the lead
battery paste prior to furnace charging. This practice improves
furnace efficiency and reduces sulfur dioxide emissions from the
furnace.2.
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
5-7
-------
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 sealed 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 the process without
generating an appreciable amount of dust.16
5.1.3 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 5-1 shows the distribution
of these configurations across the industry. The processes
associated with each of these scenarios are briefly described
below.
5.1.3.1 Blast Furnace Only. A simplified flow diagram of a
single secondary lead blast furnace system was presented in
Figure 2-2. 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.
5-8
-------
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 are hooded and ducted to the
process baghouse or to a separate sanitary baghouse for recovery
of lead-containing particulate matter.
5.1.3.2 Reverberatory or Rotarv Furnace Only. A simplified
flow diagram of a secondary lead smelter system with a single
reverberatory furnace system was presented in Figure 2-3. 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 2-3, the reverberatory
furnace charge material typically includes lead scrap, 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., semisoft 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.
5-9
-------
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.
5.1.3.3 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 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
5-10
-------
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 5-2.
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.
5.1.4 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) of 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.
5.2 FUGITIVE EMISSION SOURCES
Table 5-3 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 5-3 will not be found at all secondary lead
smelters. As indicated in Table 5-3, 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 subsections below
5-11
-------
TABLE 5-2. FEED MATERIALS AND FURNACE PRODUCTS, REPORTED BY
ONE PLANT WITH A BLAST/REVERBERATORY COMBINATION3
Weight percent of
feed
Blast furnace
Inputs
Iron
Sand
Limestone
Drosses
Reverb slag
Recycle slag
Coke
Dutputs
Raw metal
Slag and matte
Flue dust
7
3
3
15
60
7
100
56
20
5
Reverberatory furnace
Inputs
Crushed batteries
Battery plates
Flue dust - blast furnace
Flue dust - reverb furnace
Outputs
Raw metals
Reverb slag
Flue dust
aReference 1.
39
35
19
7
70
18
7
5-12
-------
TABLE 5-3.. FUGITIVE EMISSION SOURCES IN SECONDARY
LEAD SMELTERS3
Fugitive dust sources
Vehicular traffic
- Raw material delivery trucks
- In-plant material transfer (open area)
General plant traffic
Material storage bins/piles
- Unprocessed batteriesb
- Scrap lead
- Recycle slag
- Dross
- Recycled flue dust
- Cokeb
- Limestone*3
- Sandb
- Iron scrapb
- Waste materials (slag, flue dust)
Process sources
Battery wrecking unitb
Agglomeration furnace
Blast, reverberatory, and rotary furnaces
- Charging
- Lead tapping
- Slag tapping
Slag cooling
Kettle furnace
Charging
- Refining (softening and alloying)
- Dross skimming
Tapping
Castingb
aReference 17.
bThese sources are considered to be negligible sources of
lead emissions.
5-13
-------
describe the fugitive dust and process fugitive emission sources
within each category that are likely to contribute substantively
to fugitive lead emissions.
5.2.1 Fugitive Dust Sources
The primary sources of fugitive dust emissions at secondary
lead smelters are expected to be vehicular traffic on paved and
unpaved roads. 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.1"8'11"12 Lead-bearing materials deposited on roadway
surfaces will be entrained by truck travel on the roads.
Typically, lead-bearing materials such as lead scrap,
recycled 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 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.
5-14
-------
5.2.2 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
ancillary 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
futnaces are also potential sources of lead fume emissions during
normal operations and during charging and tapping operations.
5.3 ESTIMATING FUGITIVE EMISSIONS
5.3.1 Fugitive Dust Emission Estimation
As indicated in Section 5.2, the primary sources of fugitive
dust emissions are vehicle traffic on plant surfaces and raw and
recycled 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 forklifts that are used to transport
materials throughout the plant. Primary materials of concern
relative to lead emissions are scrap lead (particularly lead
5-15
-------
oxide pastes), dross, slag, and flue dust. The procedures that
can be used to estimate emissions from each of these major dust
sources are described below.
As explained in Section 2.1, lead fugitive dust emissions
from paved roads (Equation 2-2) depend on the road surface silt
loading, the lead content of the road surface silt, the average
weight of vehicles traveling on the road, and traffic volume.
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
this report.
Data on road surface dust loadings at secondary lead
smelters are summarized in Table 5-4. As shown in the table,
average silt loading at two secondary lead smelters (Plants B and
D) were 0.39 and 27.7 g/m2 (0.56 to 39.6 grains per square
foot [gr/ft2]). It is likely that the silt loading for Plant D
(27.7 g/m2 [39.6 gr/ft2]) is more representative of uncontrolled
silt loadings. Table 5-4 also includes the average lead content
(27 percent) of paved road silt for a secondary lead smelter.
Table 5-5 presents the detailed results of the road dust sampling
study at the same facility. Also included in Table 5-4 are the
results of four measurements of the lead content of paved road
surface dust at other facilities. These measurements ranged from
15 to 45 percent. The lead content of the silt was not reported.
5-16
-------
TABLE 5-4.
SUMMARY OF SECONDARY LEAD SMELTER PAVED ROAD
SURFACE DUST LOADING DATA
Plant, yr
A (1981)a
B (1992)b
B (1985)c
C (1985)c
D (1989)d
Surface dust
loading, e/m2
(gr/ft2)
29.5
(42.3)
22
(32)
116
(166)
Silt loading, g/m2
(gr/ft2)
0.39
(0.56)
27.7
(39.6)
Lead content, percent
Surface dust
45
15
31
29
Silt
27
aReference 18.
^Reference 19.
GReference 1.
^Reference 11.
Therefore, in the absence of site-specific data, the lead silt
content for Plant D (27.7 percent) should be used with
Equation 2-2 to estimate lead fugitive dust emissions from paved
road traffic. Table 5-6 presents typical vehicle weights for
secondary lead smelters. In addition, Appendix C presents
vehicle weight data for several industrial vehicles.
Methods for estimating traffic volume are described in
Section 2.1.1. Many secondary lead smelters have partially
enclosed the complete smelting/casting operations, and some
storage piles are contained in these partial enclosures.
Therefore, some reduction in traffic emissions (possibly as much
as 50 percent) should be considered for such situations.
Lead fugitive dust emissions from unpaved roads can be .
estimated (Equation 2-4) from the average silt content of the
road surface material, average vehicle speed, average vehicle
weight, average number of wheels per vehicle, number of days per
year with at least 0.254 mm (0.01 in.) of precipitation, and
traffic volume. No data were available on road surface silt
loadings for secondary lead smelters. However, Table 2-5
5-17
-------
TABLE 5-5. RESULTS OF PAVED ROAD SURFACE DUST SAMPLING
AT A SECONDARY LEAD SMELTER
Size description
Outgoing path, near
maintenance building
In front of truck
scales
Outgoing path
Outgoing path,
furthest from
wheelwash
Incoming path'
Incoming path
Partially in incoming
path
Near guardhouse
Weighted averages
Control strategy
Areas not hosed
Sample
No.
5
1
9
4
3
10
2
6
Avg.
Silt
content,
percent
22.1
24.1
24.7
19.8
23.3
31.2
22.7
32.5
23.8
Silt
loading,
g/m*
50.1
35.6
33.3
31
30.5
17.5
12.6
9.55
27.7
Pb content
of silt,
percent
38
11
26
27
29
32
14
29
27
Areas hosed
Sample
No.
7
8
Avg.
Silt
content,
percent
35.3
34.6
35.2
Silt
loading,
g/m*
13.8
6.54
10.4
Pb
content
of silt,
percent
14
34
20
Areas power washed
Sample
No.
12
Avg.
Silt
content,
percent
33.3
33.3
Silt
loading,
g/m*
2.92
2.92
Pb
content
of silt,
percent
37
37
Areas vacuumed and hosed
Sample
No.
11
Avg.
Silt
content,
percent
29.2
29.2
Silt
loading,
g/m*
4.06
4.06
Pb content
of silt,
percent
24
24
Ul
I
(->
00
Reference 11.
-------
TABLE 5-6. SUMMARY OF SECONDARY LEAD SMELTER VEHICLE DATA
Vehicle type
Trailer
Forklift
Front-end loader
Average weight (W),
Mg (ton) .
27 (29.7)
6 (6.6)
24 (34)
No. of wheels, w
18
4
4
Average vehicle
speed (S) km/hr
10
5
5
Reference
18,
includes unpaved road silt loadings for other industries, and
Table 4-3 includes unpaved rpad silt loading data for primary
lead smelters. In the absence of plant-specific data, the silt
loadings in Table 4-3 can be used to estimate silt loadings on
unpaved roads at secondary lead smelters. Table 5-6 includes
estimates of average vehicle speed, weight, and number of wheels.
Additional data on the weights of industrial vehicles can be
found in Appendix C. Appendix D presents meteorological data,
including precipitation frequency, for most of the operating
domestic secondary lead smelter locations. Precipitation
frequency for other locations can be estimated from Figure 2-1.
To estimate lead fugitive dust emissions from storage
operations for scrap lead, slag, dross, and flue dust,
Equation 2-6 can be used. The input variables include mean wind
speed, material moisture content, and the lead content of the
silt fraction. 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. Appendix D includes wind speed data for most
of the operating secondary lead smelter locations. Table 5-7
includes data on the lead content of various secondary lead
storage pile materials. In the absence of other data, the values
presented in Table 5-7 can be used for the lead content of the
silt fraction of these materials. No data on storage pile
moisture content could be located.
5-19
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TABLE 5-7. LEAD CONTENT OF SECONDARY LEAD SMELTER MATERIALS3
Material
Flue dust
Drosses
Battery scrap
Lead content, percent
Range
15-56
27-74
Average
36
51
44
Mo. of observations
4
7
1
Reference 1.
Emissions of lead from wind erosion of active storage piles
can be estimated with Equation 2-8 based on the average silt
content of the storage pile material, precipitation frequency,
and wind speed data. Appendix D includes rainfall and wind speed
data for most operating secondary lead smelter locations; no data
on storage material silt content could be located.
5.3.2 Process Fugitive Emission Estimation
The sources of process fugitive emissions from secondary
lead smelters are listed in Table 5-3. 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 5-8.
5.4 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.
5.4.1 Fugitive Dust Emission Controls1"8-20
Watering and vacuuming are the most common methods of
controlling fugitive dust emissions from vehicular traffic at
secondary lead smelters. Roads may be watered at regular
intervals by means of automatic sprinkler systems and water
trucks, or intermittently on an as-needed basis. This method can
5-20
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TABLE 5-8. EMISSION FACTORS FOR PROCESS FUGITIVE EMISSION
SOURCES IN SECONDARY LEAD SMELTERS
Source
Emission factor
Comment
Blast furnace
Totala
Charging
Slag tapping
Lead tapping
1.6-3.5 kg/Mg lead producedb
1.2kg/Mgfeedc
0.1 3 kg/Mg feed0
0.0047 kg/Mg feedc
Based on 5 percent of uncontrolled stack emissions
Based on emission test upstream from baghouse on well-
controlled system
Based on emission test upstream from baghouse on well-
controlled system
Based on emission test upstream from baghouse on well-
controlled system
Reverberatory furnace
Total
Refining kettle
Casting
Flue dust agglomeration
0.85-2.4 kg/Mg lead producedb
0.006 kg/Mg lead producedb
0.00055 kg/Mg lead charged0
0.0007 kg/Mg lead produced0
14 Kg/Mg flue dust charged0
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
Ul
N:
acharging, slag
^Reference 10.
GReference 1.
tapping, lead tapping.
-------
be quite effective for limiting dust reentrainment within plant
premises. The primary drawback of watering is that (as discussed
in Section 3.1) the dust can accumulate under vehicles and, after
drying, can be reentrained later. Some plants minimize this
problem by routinely washing down vehicle bodies or providing
wheel washes. One facility limits vehicle traffic to 8 km/hr
(5 mi/hr).
Wetting and enclosing are the primary methods used to
control fugitive dust emissions from secondary lead storage
piles. Storage piles often are located in enclosed buildings
that are ventilated to an air pollution control device. Flue
dust at some facilities is screw-conveyed directly to furnaces or
to sealed drums. At one facility, employee incentive programs
are used to limit exposure and ambient lead concentrations within
the plant. In addition, all materials are conveyed to enclosed
storage areas that are maintained under negative pressure;
vehicular traffic is prohibited in the storage area. Another
facility limits fugitive emissions from storage piles by breaking
batteries only as needed to keep pace with the furnace.
5.4.2 Process Fugitive Emission Controls1
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 3.1, 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.
5-22
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5.4.2.1 Local Ventilation Systems for Furnace Fugitives.
As indicated in Table 5-3, 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 3.2.1.
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 5-1 and 5-2 present a suggested design
concept for refining kettles. The hooding system shown in
Figure 5-1 collects emissions from charging, tapping, and
refining operations. The extension shown in Figure 5-2 collects
emissions from dressing operations.
5.4.2.2 Flue Dust Emissions Control.1 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
5-23
-------
_ FUME REMOVAL TAKE-OFF DUCTS
01
I
to
-- VOLUME FLOW RATE =
200 SCFM/SQ FT OF
KETTLE SURFACE AREA
-- DUCT VELOCITY £4,000 FT/MIN
HOOD OPENING FOR MIXER
PROVIDE HINGED COVER
PLATE WHEN MIXER NOT IN
PLACE
CONSTRUCTION NOTES
-- ENCLOSE TO PROVIDE AT
LEAST 250 FT/MIN FACE VELOCITY
AT ALL OPENINGS
-- PROVIDE ADEQUATE LIFTING
POINTS FOR HOOD ASSEMBLY
ASSOCIATED DUCTWORK
STATIONARY EXHAUST PORT
SLIDING ACESS DOORS
REFINING KETTLE
EXAMPLES OF FEASIBLE
ENGINEERING CONTROLS
ENCLOSURES HOODING-REFINING
KETTLE EMISSION CONTROLS
Figure 5-2. Suggested design concept for refining kettle hoods.21
-------
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 5-3.
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. 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
5-25
-------
VENTILATION EXHAUST
ui
I
to
REFINING KETTLE
AND HOOD
VENTILATION EXHAUST
DESIGN CHARACTERISTICS
-- ENCLOSURE TO PROVIDE CAPTURE VELOCITIES
AT OPENINGS OF 350 to 500 FT/MIN
-- TRANSPORT VELOCITIES IN DUCTS:
2: 4,000 FT/MIN
DROSS POT HOOD
DROSS POT
HINGED METAL ACCESS DOORS
EXAMPLES OF FEASIBLE
ENGINEERING CONTROLS
ENCLOSURE HOODING-
DROSS POT HOOD
Figure 5-3. Suggested design concept for dross pot hoods.21
-------
PROCESS VENT
BAGHOUSE
DUST HOPPER
BURNER
SCREW
CONVEYOR
A I yMW^^
"x"
AGGLOMERATION
FURNACE
SLOPED HEARTH
MOLTEN DUST
. COOLING/TRANSPORTATION
CRUCIBLE
Figure 5-4. Flash agglomeration furnace.14
5-27
-------
coke and flux and loaded into the top of the blast furnace along
with other charge materials.
5.5 REFERENCES FOR CHAPTER 5
1. Rives, G. D., and A. J. Miles (Radian), Control of Arsenic
Emissions from the Secondary Lead Industry-Technical
Document, EPA Contract No. 68-02-3816, Prepared for the
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, March 18, 1985.
2. Process Description and Emissions, Secondary Lead Smelting,
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, 1993.
3. Cavender, K. and R. Pelt (Radian), Final Trip Report, Site
Visit to The Doe Run Company, Boss, Missouri, on April 15,
1992, prepared for Emission Standards Division, U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, July 9, 1992.
4. Cavender, K. (Radian), Draft Trip Report, Site Visit to East
Penn Manufacturing Company, Inc., Lyon Station,
Pennsylvania, on September 26, 1991, prepared for Emission
Standards Division, U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina, March 4, 1992.
5. Cavender, K., and B. Palmer (Radian), Final Trip Report,
Site Visit to GNB, Incorporated, Frisco, Texas, on
January 23, 1991, prepared for Emission Standards Division,
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, December 14, 1992.
6. Cavender, K. and G. Rives, (Radian), Final Trip Report, Site
Visit to GNB, Incorporated, Vernon, California, on May 20,
1991, prepared for Emission Standards Division, U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, September 13, 1992.
7. Emission Test Report (Draft): HAP Emission Testing on
Selected Sources at a Secondary Lead Smelter, Schuylkill
Metals Corporation, Forest City, Missouri, prepared for
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, January 1993.
8. Emission Test Report (Draft): HAP Emission Testing on
Selected Sources at a Secondary Lead Smelter, Tejas
Resources, Inc., Terrell, Texas, prepared for U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, December 1992.
9. Mineral Industrial Surveys-Lead, in June 1993, Bureau of
Mines, U. S. Department of the Interior, September 23, 1993.
5-28
-------
10. Compilation of Air Pollutant Emission Factors, Volume I:
Stationary Point and Area Sources, AP 42. U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, September 1993.
11. 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
U. S. Environmental Protection Agency, Atlanta, Georgia,
September 15, 1989.
12. Fuchs, M. R., M. J. Krall, and G. D. Rives (Radian),
Emission Test Report: Chloride Metals Secondary Smelter,
Tampa, Florida, Contract No. 68-02-3850, prepared for U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, March 14, 1985.
13. Development of New Source Performance Standards for
Secondary Lead Smelting Industry, EPA Contract
No. 68-02-3059,, prepared for U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina, Midwest
Research Institute, May 30, 1980.
14. Burton, D. J., R. T. Coleman, W. M. Coltharp, J. R. Hoover,
and R. Vandervort (Radian), Control Technology Assessment:
The Secondary Nonferrous Smelting Industry, NIOSH Contract
No. 200-77-0008, prepared for the U.S. Department of Health
and Human Services, Cincinnati, Ohio, October 1980.
15. Prengaman, R. D., J?ever£>eratory Furnace—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.
16. Coleman, R., Jr., and R. Vandervort, Demonstration of
Fugitive Emission Controls at a Secondary Lead Smelter, In:
Lead-Zinc-Tin 1980, J. M. Cigan, T. S. Mackey, and
T. J. O'Keefe (eds.), Proceedings of TMS-AIME World
Symposium on Metallurgy and Environmental Control, Las
Vegas, Nevada, February 24-28, 1980.
17. Technical Guidance for Control of Industrial Process
Fugitive Particulate Emissions, EPA-450/3-77-010, U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, March 1977.
18. Technical Memorandum, from L. C. Sutton and K. A. Cavender
(Radian), to George Streit, Emission Standards Division,
U. S. Environmental Protection Agency. Estimating Fugitive
Particulate Emissions From Secondary Lead Smelters,
March 24, 1992.
5-29
-------
19. Friedman, J. N. (Interpoll Laboratories, Inc.)/ Lead A±r
Analysis for the Gopher Smelting and Refining Company
Facility in Eagan, Minnesota, prepared for the Gopher
Smelting and Refining Company Facility, Eagan, Minnesota,
January 7, 1993.
20. K. Cavender (Radian), Final Trip Report, Site Visit to Exide
Corporation, Reading, Pennsylvania, on September 25, 1991,
prepared for Emission Standards Division, U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, March 4, 1993.
21. 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.
5-30
-------
6.0 LEAD-ACID BATTERY MANUFACTURING
6.1 PROCESS DESCRIPTION1
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. However, 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 6-1.
6.1.1 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
machines are also found. After the grids have solidified, they
are ejected from the molds, trimmed, and stacked.
6.1.2 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 temperatures. 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
6-1
-------
A A
" PARTICULATE ' ^ARTICULATE
| MATTER | MATTER
LEAD OXIDE
PRODUCTION
LEAD PASTE
MIXING
' PARTICULATE
, MATTER
GRID CASTING
FURNACE
GRID
CASTING
GRID CASTING OPERATION
[ PARTICULATE
, MATTER
1 ~ r
f
GRID k PLATE ^ PLATE > ELEMENT ,
PASTING STACKING ~" BURNING ASSEMBLY
THREE PROCESS OPERATION
a\
to
A
J SULFURIC
, ACID MIST
FORMATION
RINSING AND
DRYING
ASSEMBLY INTO
BATTERY CASE
FRESH
ACID
A'
J SULFURIC
! ACID MIST
FORMATION
ACID REFILL
WASH AND
PAINT
SHIPPING
->. PROCESS STREAM
>. ATMOSPHERIC EMISSION
STREAM
Figure 6-1. Process flow diagram for storage battery production.2
-------
uses no expander. After mixing, the paste is applied to the
grids, flash dried, stacked, and cured.
6.1.3 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.
6.1.4 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.
6.1.5 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 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.
6-3
-------
The larger particles captured by the cyclone are then ground in a
hammermill and conveyed to the fabric filter.
6.1.6 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.
6.2 FUGITIVE EMISSION SOURCES1-3-8
General descriptions of fugitive dust sources and process
fugitive sources are provided in Sections 2.1 and 2.2,
respectively. Fugitive dust and process fugitive sources
specific to lead-acid battery manufacturing are discussed in
Sections 6.2.1 and 6.2.2, respectively.
In order to maintain Occupational Safety and Health
Administration (OSHA) requirements for ambient lead
concentrations, fugitive emissions are tightly controlled at
lead-acid battery manufacturing plants. Unlike most smelting
operations, 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.
6.2.1 Fugitive Dust
As described in Section 2.1, fugitive dust sources include
paved roads, unpaved roads, and storage piles. At most
industrial facilities, the primary fugitive dust sources are
likely to be paved and unpaved roads; these facilities typically
do not have open storage piles. Little information on fugitive
dust emissions from lead-acid battery manufacturing facilities
was obtained in the course of this study. However, the available
information indicates that the plant roads most likely to have
6-4
-------
the highest levels of fugitive lead emissions are the roads in
the vicinity of the lead oxide transfer and storage operations.
When lead oxide is purchased from another facility, it typically
is transported in sealed tanks and conveyed by pipe directly into
storage silos without exposure to the plant environment. On rare
occasions, pipe connections may fail, resulting in a release of
lead oxide to the plant environment. This material later can be
reentrained into the ambient air by traffic in the vicinity of
the release.
6.2.2 Process Fugitives
Descriptions of the general types of process fugitive
emission sources can be found in Section 2.2. Because lead-acid
battery manufacturing plants are enclosed, and specific processes
such as the grid casting, paste mixing, three-process operation
are hooded and vented, process fugitive emissions are considered
to be negligible. However, fugitive lead potentially can be
emitted from building doors and other openings if the ventilation
system does not maintain continuous airflow into the building
through these openings.
6.3 ESTIMATING FUGITIVE EMISSIONS
The following sections discuss procedures for estimating
fugitive lead emissions from lead-acid battery manufacturing
sources. Section 6.3.1 addresses estimating lead emissions from
fugitive dust sources, and Section 6.3.2 addresses estimating
process fugitive lead emissions.
6.3.1 Fugitive Dust
Lead emissions from paved and unpaved roads can be estimated
using the equations provided in Section 2.1. Because of
variations from plant to plant in the parameters used in these
equations, site-specific data should be used whenever possible to
estimate fugitive dust emissions. Section 2.1 also provides
guidelines for obtaining the data needed for the input parameters
for these equations. Sampling and analytical procedures for road
dust are provided in Appendices A and B, and analytical methods
for analyzing road material samples for lead are listed in Table
2-3. If plant-specific data are unavailable, default values for
6-5
-------
many of the fugitive dust equation parameters can be taken from
the data presented in this report. However, estimates derived
using the default values presented in this document should be
used for preliminary assessment only.
To estimate lead fugitive dust emissions from paved roads
(Equation 2-2), average silt loading, the lead content of the
road dust silt fraction, average vehicle weights, and traffic
volume are required. Table 2-1 includes data on silt loadings of
paved roads for a number of industrial facilities. In addition,
Tables 4-3, 5-4, 5-5, 9-5, and 9-6 include data on silt loadings
at some of the industrial facilities addressed in this report.
In the absence of plant-specific data, the information in these
tables can be used to estimate silt loadings. Data on the lead
content of road silt were not available for lead-acid battery
manufacturing facilities. Because processes are enclosed and
good housekeeping practices are maintained at these facilities,
it is likely that the lead content of road silt is negligible.
Therefore, only site-specific data should be used to estimate
this parameter for this industry. Appendix C provides
information on weights of several industrial vehicles, and
Section 2.1.1 describes methods for estimating traffic volume.
Lead fugitive dust emissions from unpaved roads can be
estimated using Equation 2-4. The input parameters for the
equation include the silt content of the road surface material;
the lead content of the silt; average vehicle speed, weight, and
number of wheels; precipitation frequency; and traffic volume.
No data were available on unpaved road dust from lead-acid
battery manufacturing plants. However, Tables 2-5, 4-3, and 9-7
include data on the unpaved road silt content for a number of
industrial facilities. Only site-specific data should be used to
estimate the lead content of unpaved road silt for this industry.
Table 5-6 and Appendix C include data that can be used to
estimate vehicle weight, speed, and number of wheels. Figure 2-1
can be used to estimate the rainfall frequency, and traffic
volume can be estimated using the procedures described in
Section 2.1.1.
6-6
-------
6.3.2 Process Fugitives
As explained previously, process fugitive lead emissions are
likely to be negligible for lead-acid battery manufacturing
facilities. Therefore, no discussion on estimating the magnitude
of process fugitive lead emission rates is presented in this
report.
6.4 CONTROLLING FUGITIVE EMISSIONS1'3'8
General descriptions of fugitive dust and process fugitive
emission controls are provided in Sections 3.1 and 3.2,
respectively. Methods used to control process fugitive and
fugitive dust emissions at lead-acid battery manufacturing
facilities are summarized in Sections 6.4.1 and 6.4.2,
respectively.
6.4.1 Fugitive Dust
Lead fugitive dust emissions at a typical lead-acid battery
manufacturing plant are most likely to be associated with 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.
6.4.2 Process Fugitives
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
6-7
-------
devices at lead-acid battery manufacturing plants, are listed in
Table 6-1.
TABLE 6-1. LEAD-ACID BATTERY MANUFACTURING—
TYPICAL CONTROL DEVICES3
Process
1.
2.
3.
4.
5.
Grid casting
Paste mixing
a. Charging
b. Mixing
Three-process
operation
Lead oxide production
Lead reclamation
Typical control device
Scrubber (impingement,
Fabric filter
Uncontrolled
cascade)
Fabric filter
Scrubber (impingement)
Fabric filter
Scrubber (impingement)
Mechanical collector (e.g.,
cyclone) followed by baghouse
Scrubber (impingement,
Fabric filter
cascade)
aReference 1.
6.5 REFERENCES FOR CHAPTER 6
1. 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.
2. Compilation of Air Pollutant Emission Factorsf Volume I:
Stationary Point and Area Sources, AP-42, U. S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
September 1993.
3. Memo from Michelitsch, D. M., U. S. Environmental Protection
Agency, Industrial Studies Branch, to Durkee, K. R., U. S.
Environmental Protection Agency, Industrial Studies Branch,
October 18, 1988, Report on July 20, 1988, trip to Douglas
Battery Manufacturing Company, Winston-Salem, North Carolina.
4. Memo from Michelitsch, D. M., U. S. Environmental Protection
Agency, Industrial Studies Branch, to Durkee, K. R., U. S.
Environmental Protection Agency, Industrial Studies Branch,
November 1, 1988, Report on July 26, 1988, trip to Exide
Corporation, Reading, Pennsylvania.
6-8
-------
5. Memo from Michelitsch, D. M., U. S. Environmental Protection
Agency, Industrial Studies Branch, to Durkee, K. R., U. S.
Environmental Protection Agency, Industrial Studies Branch,
November 7, 1988, .Report on July 13, 1988, trip to Trojan
Battery Manufacturing Company, Lithonia, Georgia.
6. Memo from Michelitsch, D. M., U. S. Environmental Protection
Agency, Industrial Studies Branch, to Durkee, K. R., U. S.
Environmental Protection Agency, Industrial Studies Branch,
December 6, 1988, .Report on July 19, 1988, trip to Johnson
Controls, Incorporated, Winston-Salem, North Carolina.
7. Memo from Michelitsch, D. M., U. S. Environmental Protection
Agency, Industrial Studies Branch, to Durkee, K. R., U. S.
Environmental Protection Agency, Industrial Studies Branch,
December 6, 1988, .Report on July 27, 1988, trip to East Penn
Manufacturing Company, Lyon Station, Pennsylvania.
B. Memo from Michelitsch, D. M., U. S. Environmental Protection
Agency, Industrial Studies Branch, to Durkee, K. R., U. S.
Environmental Protection Agency, Industrial Studies Branch,
January 9, 1989, .Report on July 12, 1988, trip to C&D Charter
Power Systems, Inc., Conyers, Georgia.
6-9
-------
7.0 GRAY IRON FOUNDRIES
7.1 PROCESS DESCRIPTION1
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, 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
7-1
-------
5. Waste handling.
A general flow diagram of foundry operations is presented in
Figure 7-1 and a block diagram of core and mold making is
presented in Figure 7-2. 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 7-1, 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 metallics 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.
Further descriptions of the specific foundry operations are
included in Section 7.2.2 on sources of iron foundry process
fugitive emissions.
7-2
-------
SAND
UkCSTONE
v™/
EMSSIONS
CORE SAND
*oL-oL-
CORE BINDER
CORE 4 MOLDING MAKING AREA
(SEE FIGURE 7-2)
• nnnon
SAND STORM
^_y ^y
-»aaq~^
BINDER STORAGE
Figure 7-1. Composite flow diagram for the gray iron foundry industry.
(Numbers refer to source listings in Table 7-1).*
-------
RETURN SAND
WATER
NEW SAND
AND BINDERS
SAND AND
BINDERS OR
PREPARED
SAND
SAND AND
BINDERS OR
PREPARED
SAND
SAND AND
BINDERS
TO POURING
AREA
CHEMICAL
CATALYST
Figure 7-2. Mold and core making.
1
7-4
-------
7.2 FUGITIVE EMISSION SOURCES
General descriptions of fugitive dust sources and process
fugitive sources are provided in Sections 2.1 and 2.2,
respectively. Fugitive dust and process fugitive sources
specific to iron foundries are discussed in Sections 7.2.1 and
7.2.2, respectively.
7.2.1 Fugitive Dust
As described in Section 2.1, fugitive dust sources include
paved roads, unpaved roads, and storage piles. At most
industrial facilities, the primary fugitive dust sources are
likely to be paved and unpaved roads. Little information on
fugitive dust emissions from iron foundries was obtained in the
course of this study.
. The paved roads most likely to have the highest levels of
fugitive lead emissions at iron foundries are those in the
vicinity of the furnaces, slag haul roads, and roads in the
vicinity of slag storage piles. In addition, roads associated
with fabric filter dust removal and disposal and any plant road
on which slag is used as ballast are potentially significant
sources of fugitive lead emissions.
Lead fugitive dust may be emitted from the handling and
storage of scrap materials and from wind erosion of slag piles
and open areas around the plant. However, the fugitive lead
emissions from those sources are likely to be negligible.
7.2.2 Process Fugitives
Iron foundries contain a variety of process sources with the
potential for emitting PM, 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 7-1. Those fugitive sources that have
the greatest potential to be significant at a specific plant are
so signified in Table 7-1. Each of these sources is discussed
briefly below. Descriptions of general types of process fugitive
7-5
-------
TABLE 7-1. FUGITIVE EMISSION SOURCES IN IRON FOUNDRIES
Source
No.b
Source identification
Pollutant
PM
Lead
Potentially
significant source
Raw material storage and handling
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
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
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Melting and casting
16
17
18
19
20
21
22
23
24
25
26
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
7-6
-------
TABLE 7-1. (continued)
Source
No.b
Source identification
Pollutant
PM
Lead
Potentially
significant source
Cleaning and finishing
27
28
29
30
Shakeout
Return sand system
Cooling and cleaning
Grinding
X
X
X
X
X
X
X
Mold and core preparation
31
32
33
34
35
36
37
38
39
40
41
Sand charge to mixer/muller
Dry sand mixing or mulling
Holder
Cold set mold
Oven bake core box
Core oven leakage
Shell or hot box heat
Cold box core or mold
No bake core box
Core cooling
Core wash
X
X
X
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 1.
^Sources are identified by number in Figures 7-1 and 7-2.
emission sources are presented in Section 2.2 of this report.
Raw materials are used in two areas of the foundry.
Metallics, 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.
7-7
-------
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 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
7-8
-------
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 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 metallies 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
7-9
-------
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 prblem.
7.3 ESTIMATING FUGITIVE EMISSIONS
The following sections discuss procedures for estimating
fugitive lead emissions from iron foundry sources. Section 7.3.1
addresses estimating lead emissions from fugitive dust sources,
and Section 7.3.2 addresses estimating process fugitive lead
emissions.
7.3.1 Fugitive Dust
Lead emissions from paved and unpaved roads and storage
piles can be estimated using the equations provided in
Section 2.1. Because of variations from plant to plant in the
parameters used in these equations, site-specific data should be
used whenever possible to estimate fugitive dust emissions.
Section 2.1 also provides guidelines for obtaining the data
needed for the input parameters for these equations. Sampling
and analytical procedures for road dust and storage pile samples
are provided in Appendices A and B, and analytical methods for
analyzing road and storage pile material samples for lead are
listed in Table 2-3. If plant-specific data are unavailable,
default values for many of the fugitive dust equation parameters
can be taken from the data presented in this report. However,
estimates derived using the default values presented in this
document should be used for preliminary assessment only.
7-10
-------
To estimate lead fugitive dust emissions from paved roads
(Equation 2-2), average silt loading, the lead content of the
road dust silt fraction, average vehicle weights, and traffic
volume are required. Table 2-1 includes data on silt loadings of
paved roads for several industries including iron and steel
facilities. In the absence of plant specific data, the
information in Table 2-1 can be used to estimate silt loadings.
Data on the lead content of road silt were not available for iron
foundries. Appendix C provides information on weights of several
industrial vehicles, and Section 2.1.1 describes methods for
estimating traffic volume.
Lead fugitive dust emissions from unpaved roads can be
estimated using Equation 2-4. The input parameters for the
equation include the silt content of the road surface material;
the lead content of the silt; average vehicle speed, weight, and
number of wheels; precipitation frequency; and traffic volume.
No data were available on iron foundry plant road dust. However,
Table 2-5 includes data on the unpaved road silt content for a
number of industries including iron and steel plants. Table 5-6
and Appendix C include data that can be used to estimate vehicle
weight, speed, and number of wheels. Figure 2-1 can be used to
estimate the rainfall frequency, and traffic volume can be
estimated using procedures described in Section 2.1.1.
Equations 2-6 and 2-8 can be used to estimate lead fugitive
dust emissions from storage piles. To estimate emissions related
to storage pile handling and transfer (Equation 2-6), mean wind
speed, material moisture content, and the lead content of the
silt fraction of the storage pile material are required. Mean
wind speeds are readily available from local meteorological
stations, and Appendix D includes data for several cities in the
United States. No data on storage pile material moisture and
lead content for iron foundries were located in the corse of tmis
study. The lead content of storage pile material silt can be
estimated from the lead content of the material stored. To
estimate wind erosion of active storage piles (Equation 2-8),
data are needed on silt content, lead content of the silt
7-11
-------
fraction of the storage pile material, rainfall frequency, and
percentage of time that wind speed exceeds 5.4 m/sec (12 mph).
Data on wind speed and rainfall frequency can be obtained from
local meteorological stations. Alternatively, Appendix D nd
Figure 2-1 can be used to estimate those parameters.
7.3.2 Process Fugitives
The primary sources of process fugitive lead emissions from
iron foundries, as indicated in Table 7-1 include furnace
charging, melting, and tapping; iron inoculation and pouring; and
product grinding. Emission factors for PM and lead emissions
from iron foundry sources are summarized in Table 7-2. In
general, the emission factors presented in the table are based on
limited test and process data.
7.4 CONTROLLING FUGITIVE EMISSIONS1
General descriptions of fugitive dust and process fugitive
emission controls are provided in Sections 3.1 and 3.2,
respectively. Little information on measures used to control
fugitive dust emissions at iron foundries was obtained in the
course of this study. .However, the information provided in
Sections 3.1 on fugitive dust controls generally is applicable to
iron foundries. The remainder of this section presents
information on process fugitive emission controls for the iron
foundry industry.
Fugitive emission controls used in iron foundries can be
classified as (1) preventive process and operating changes and
(2) capture and removal methods for fugitive emission streams.
Preventive measures include better monitoring of feed materials,
increased maintenance, more efficient use of equipment, and
redesign of process equipment to increase efficiency. Capture
and removal methods used in iron foundries consist of complete or
partial enclosures. Partial enclosures include fixed and movable
hoods on furnace charging, casting, tapping, and covered
conveyors with hooded conveyor transfer points. The following
paragraphs describe some of the methods used to control iron
foundry sources that are likely to be the most significant
7-12
-------
TABLE 7-2. FUGITIVE EMISSION FACTORS FOR IRON FOUNDRIES
Source
Cupolab
Electric arc furnace^
Scrap handling0
Pouring, cooling*
Shakeout0
Emission factors3
kg/Mg (Ib/ton)
PM
0.69
(1.4)
0.63
(1.3)
0.3
(0.6)
2.1
(4.2)
1.6
(3.2)
Lead
0.0005-0.06
(0.0010-0.12)
0.005-0.054
(0.010-0.11)
Comment
Based on 10 percent of
uncontrolled stack emissions
Based on same lead to PM
ratio as cupola
aAll emission factors are in kg/Mg (Ib/ton) of metal produced.
^Reference 2.
cReference 1.
emitters of fugitive lead emissions. Table 7-3 lists the
available control measures for each iron foundry fugitive
emission source.
Local exhaust hoods are used to control fugitive emissions
from iron foundry cupola tapping. If a permanent hood is not
feasible, plants use movable hooding systems that consist of a
telescoping duct with a funnel-type hood suspended near the
cupola. To control fugitive emissions from EAF's, the available
options include canopy hooding, closed charging systems, hooding
charging buckets, total furnace enclosures, and close capture
hooding. Close capture hooding systems also are used to control
fugitive emissions from electric induction furnaces. Fugitive
emissions from iron inoculation are controlled primarily with
either the furnace tapping control system or a separate
enclosure.
The mold pouring and cooling floor in an iron foundry is one
of the most difficult areas to control, due to the variations in
pouring methods and the large areas over which emissions occur.
The alternatives for controlling fugitive emissions from these
areas include using stationary hooded pouring stations in
7-13
-------
TABLE 7-3. PROCESS FUGITIVE EMISSION CONTROLS FOR GRAY IRON FOUNDRIES
Fugitive emissions source
Raw material input
Storage
Coke
Sand
Scrap
Handling and transfer
New sand handling
Coke handling
Spent sand handling
Melting and casting
Cupola tapping
Electric arc furnace
Induction furnace
Capture or abatement system
Method
Enclosed storage
Pnematic transfer
Covered belts and
enclosed transfer
Hooded screens
Enclosed transfer and
covered belts
Covered belts and
enclosed transfer
Schumacher process
Stationary hood
Moveable hood
Canopy hood
Closed charging system
Hooded charging
bucket
Furnace enclosure
Close capture hooding
Close capture hooding
Effectiveness
99%
100%
Good
Good
Good
Good
99% +
DI
DI
DI
DI
DI
DI
60-85%
90-95%
Problems
None
None
None
None
None
None
Some capital investment
Interference with
operations
Capture problems with
cross draft, high flows
Requires sized scrap,
does not control tapping
Does not control tapping
Interference with
operation
None
None
Removal system
Method
-
Wet scrubber
Baghouse
Wet scrubber
Baghouse
Wet scrubber
Baghouse
Wet scrubber
-
Primary capture system
Primary capture system
Baghouse
Baghouse
Main melting system
Baghouse
Baghouse
Baghouse
Effectiveness
-
99% +
99% +
99% +
99% +
99% +
99% +
99% +
-
90%
90%
99%
99%
—
99%
99%
99%
Problems
-
None
None
None
None
None
None
None
-
May have excessive fine
particles
Costs high due to large
volumes
No data
No data
No data
No data
No data
I
M
*.
-------
TABLE 7-3. (continued)
Fugitive emissions source
Iron innoculation
Iron pouring
Floor pouring
Pouring station
Iron cooling
Floor pouring
Pouring station
Product finishing
Vibrating shakeout
Revolving shakeout
Grinding
Core and mold preparation
Mulling
Shellcore or hot box
Heating
Holding pallet
Cold set
Core wash
Molding
Waste handling
Slag quench
Waste sand transfer
Storage piles
Capture or abatement system
Method
Tapping hood
Booth
Building evacuation
Mobile vent
Pouring hood
Building evacuation
Mold funnel
Total enclosure
Side draft hood
Enclosure
Swing grinder booth
Downdraft table
Hooded charging
Overhead hood
Moveable hood
Closed system
Spray booth
None needed
DI
Wetting
Wetting
Effectiveness
DI
DI
DI
DI
Good
DI
Good
Good
Moderate
DI
DI
DI
Good
DI
DI
DI
DI
-
-
90-95%
DI
Problems
May interfere with
melting operations or
may be impossible to
interface
May be safety hazard
High cost
Questionable
effectiveness
None
High cost
None
None
None
None
None
Size limitations
None
May be ineffective
May be a safety hazard
during torching
-
-
-
-
Removal system
Method
Main melting system
Baghouse
DI
DI
DI
DI
DI
Wet scrubber
Wet scrubber
Wet scrubber
Wet scrubber
Baghouse
Wet scrubber
Wet scrubber
Chemical scrubber
Chemical scrubber
Chemical scrubber
DI
-
DI
-
-
Effectiveness
99%
99%
-
—
-
-
-
98-99%
98-99%
98-99%
99% +
99% +
99% +
99% +
90-100%
90-100%
90-100%
—
-
-
-
-
Problems
No data
No data
-
—
-
-
-
None
None
None
None
None
None
None
None
None
None
—
-
-
-
-
Reference 1.
DI = data insufficient.
-------
conjunction with an enclosed cooling conveyor. For those
foundries in which the mold in placed on the floor and the ladle
is moved to the mold, some type of movable hooding system or
building evacuation is required for controlling fugitive
emissions. The use of permanent mold casting instead of green
sand molds with sand cores has been demonstrated to reduce PM
emissions by 99 percent.
The selection of control technology for grinding operations
depend on the type of grinding, casting, and other operations
that may have interfacing control devices. Many control systems
for the grinding operation are custom designed. Emissions from a
swing-frame grinder are best controlled by an exhaust hood ducted
to a fabric filter or wet scrubber. For bench and some portable
grinders, self-contained capture and removal systems with
downdraft exhaust have been used. In addition, complete
enclosures can be used to control fugitive emissions from iron
foundry product grinding.
7.5 REFERENCES FOR CHAPTER 7
1. Wallace, D., and C. Cowherd' (Midwest Research Institute),
EPA-600/7-79-195, Fugitive Emissions from Iron Foundries,
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, August 1979.
2. Compilation of Air Pollutant Emission Factors, Volume J:
Stationary Point and Area Sources, AP-42, U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, September 1993.
7-16
-------
8.0 PRIMARY COPPER SMELTING
8.1 PROCESS DESCRIPTION1'11
In the United States, copper is produced from sulfide ore
concentrates, principally using pyrometallurgical smelting
methods. A conventional pyrometallurgical copper smelting
process is illustrated in Figure 8-1. The process includes
drying ore concentrates to produce calcine, smelting ore
concentrates (green feed) to produce matte, and converting the
matte to yield a blister copper product (about 99 percent pure).
Typically, the blister copper is fire refined in an anode
furnace, cast into anodes, and sent to an electrolytic refinery
to eliminate impurities. The drying, smelting, converting, slag
recycling, and fire refining operations are discussed in
Sections 8.1.1 through 8.1.5, respectively.
There are currently 8 primary copper smelting operations in
the United States. The names and locations of each are listed in
Table 8-1.
8.1.1 Drying
Primary copper smelting begins by concentrating and drying
the ores to produce calcine. Ores usually contain less than
1 percent copper; therefore, must be concentrated prior to
entering the dryers. Concentrations of 15 to 35 percent copper
are produced at the mine site by crushing, grinding, and
flotation. The remainder of the concentrate consists primarily
of sulfur, ranging from 25 to 35 percent; 25 percent iron; and
10 percent water. Some concentrates also contain significant
quantities of arsenic, cadmium, lead, antimony and other heavy
metals. The concentrations may be cleaned, thickened, filtered,
8-1
-------
3
o
05
a
05
J5
en
o
O
Ore Concentrates with Silica Fluxes
—"I
Fuel
Air
DRYING
Fuel
Air
OFFGAS
Calcine
SMELTING
t
Slag Dumped or
(Recycled 0.5% Cu)
Air
OFFGAS
MATTE (-40% Cu)
CONVERTING
Natural or Reformulated Gas
Green Poles or Logs
Fuel
Air
Slag to Converter
OFFGAS
Blister Copper (98.5% Cu)
FIRE REFINING
J
OFFGAS
Anode Copper (99.5% Cu)
To Electrolytic Refinery
Figure 8-1. Typical primary copper smelting process
1
8-2
-------
TABLE 8-1. PRIMARY COPPER SMELTING FACILITIES
Primary Copper .Smelter
Magma Copper Company
Asarco, Incorporated
Cyprus Miami Mining Corporation
Phelps Dodge Chino Mines Company
Phelps Dodge Mining Company
Asarco, Incorporated
Kennecott Utah Copper
Copper Range Company
Location
San Manuel, AZ
Hayden , CO
Claypool, AZ
Hurley, NM
Playas, NM
El Paso, TX
Magna , UT
White Pine, MI
and then dried before entering the smelters.
Ore concentrates are dried in either a fluidized bed or a
rotary dryer. The feed material for fluidized beds includes a
mixture of finely ground ore (60 percent passing a 200 mesh
[0.075 millimeter] sieve), external fuel, and air.'
8.1.2 Smelting
In the smelting process, hot calcines from the dried
concentrate are melted with siliceous flux, and recycled
converter slag in a smelting furnace to produce copper matte.
Copper matte is a molten mixture of cuprous sulfide (Cu2S) ,
ferrous sulfide (FeS), and some trace heavy metals. The required
heat comes from partial oxidation of the sulfide charge and from
burning external fuel. The liquid matte is formed at about 980°C
(1800°F) and the furnace temperature may reach 1315°C (2400°F).4
Most of the iron and some of the impurities in the charge oxidize
with the fluxes to form a slag atop the molten bath. The slag is
periodically removed and discarded to a dump site or sent to a
slag cleaning furnace. The copper matte remains in the furnace
until tapped from the bottom. Mattes produced by the domestic
industry range from 45 to 75 percent copper, 55 percent copper
being the most common. The copper percentage is referred to as
the matte grade.
8-3
-------
Currently, four smelting furnace technologies are used in
the United States: reverberatory, IsaSmelt, flash, and
Noranda.M1 Each furnace technology is briefly described in
Sections 8.1.2.1 through 8.1.2.4.
8.1.2.1 Reverberatory Furnaces. Reverberatory furnace
operation is a continuous process. The process involves the
frequent charging of calcine, fuel, air, and converter slag; the
periodic tapping of matte; and the skimming of slag. The fuel
supplied to the furnace may be oil, gas, or pulverized coal. The
furnace temperature may exceed 1500°C (2730°F). A schematic of a
typical reverberatory furnace is shown in Figure 8-2.
8.1.2.2 IsaSmelt Furnaces. Ore concentrates enter an Isa
vessel where oxygen is fed via a lance. Details on the design
and operation of this type of furnace are considered proprietary
and are not available.
8.1.2.3 Flash Furnaces. Outokumpu, Inco, and ConTop
cyclone reactors are flash furnaces. Flash furnace smelting
combines the operations of drying and smelting to produce a high
grade copper matte from concentrates and flux. In flash
smelting, dried ore concentrates and finely ground fluxes are
injected with oxygen or preheated air, or a mixture of both into
a specially designed furnace controlled at approximately 1000°C
(1830°F). Flash furnaces, in contrast to reverberatory furnaces,
use the heat generated from partial oxidation of their sulfide
charge to provide much or all of the energy (heat) required for
smelting. ConTop cyclone reactors use oxygenated fuel to
generate the heat required for oxidation. Slag produced by flash
furnace operations contains significantly higher amounts of
copper than slag produced from reverberatory furnace operations.
Flash furnaces also produce offgas streams contaihing high
concentrations of SO2.
8.1.2.4 Noranda Process. The original design of the
Noranda process allowed the continuous production of blister
copper in a single vessel by effectively combining drying,
smelting, and converting into one operation. However,
8-4
-------
CALCINE
FUEL
CONVERTER
SLAG
FETTLING DRAG
CONVEYOR
OFFGAS
AIR AND OXYGEN
BURNERS
SLAG
MATTE
'FETTLING PINES
Figure 8-2. Reverberatory furnace.
8-5
-------
metallurgical problems led to the use of multiple reactors
(vessels) for the production of copper matte. As in flash
smelting, the Noranda process takes advantage of the heat energy
available from the copper ore. The remaining thermal energy
required is supplied by oil burners or by coal mixed with the ore
concentrates.
8.1.3 Converting
The next step in the production of primary copper is
converting. Converting is a batch process that eliminates the
remaining iron and sulfur present in the matte and leaves molten
"blister" copper. The matte from the smelter is transferred to
the converter via a ladle or crane. A typical copper converter
is shown in Figure 8-3.
Converter furnaces burn matte, recycled fire-refined furnace
slag, silica flux, and natural gas. Air or oxygen rich air is
blown through the molten matte. The reaction is carried out in
the furnace at 1200°C (2200°F).* Iron sulfide (FeS) is oxidized
to iron oxide (FeO) and S02; and the FeO blowing and slag
skimming are repeated until an adequate amount of relatively pure
Cu2S, called "white metal," accumulates in the bottom of the
converter. Lead and other trace elements are also oxidized and
volatilized. A renewed air blast (also known as the finish blow)
oxidizes the copper sulfide to S02, leaving blister copper in the
converter. The SO2 produced throughout the operation is normally
routed to an SO2 recovery plant. The blister copper is removed
and transferred to refining facilities. An average converter
processes approximately 270 Mg/day (300 tons/day) of copper
matte.4
All but one U.S. smelter use Fierce-Smith converters, which
are refractory lined cylindrical steel shells mounted on
trunnions at either end and rotated about the major axis for
charging and pouring. An opening in the center of the converter
functions as a mouth through which molten matte, siliceous flux,
and scrap copper are charged and gaseous products are vented.
8-6
-------
OFFGAS
TUYERE PIPES
03
I
SILICEOUS
FLUX
PNEUMATIC
PUNCHERS
AIR
Figure 8-3. Copper converter.4
-------
One domestic smelter uses Hoboken converters. The Hoboken
converter is essentially like a conventional Fierce-Smith
converter, except that one end of the vessel is fitted with a
side flue shaped like an inverted U. This flue arrangement
permits siphoning of gases from the interior of the converter
directly to the offgas collection system, leaving the converter
mouth under a slight vacuum.
8.1.4 Slag Recycling
If slag from the flash furnace and converter contains a
recoverable amount of copper, then the slag may be treated in a
slag cleaning furnace. Slag cleaning furnaces usually are small
electric furnaces. Heat is generated by the flow of an electric
current in carbon electrodes lowered through the furnace roof and
submerged into the slag layer of the molten bath. The slag
settles under reducing conditions with the addition of coke or
iron sulfide. The copper oxide in the slag is converted to
copper sulfide, subsequently removed from the furnace and charged
to a converter with regular matte. If the copper content of the
slag is low, the slag is discarded to a dump site.
8.1.5 Fire Refining
Blister copper usually contains from 98.5 to 99.5 percent
pure copper. Impurities may include gold, silver, antimony,
arsenic, bismuth, iron, lead, nickel, selenium, sulfur,
tellurium, and zinc. To purify blister copper further, fire
refining and electrolytic refining are used. In fire refining,
blister copper is placed in an anode furnace, a flux is usually
added and air is blown through the molten mixture to oxidize any
remaining impurities. These impurities are removed as a slag and
returned to the converter. The remaining metal bath is subjected
to a reducing atmosphere to reconvert cuprous oxide to copper.
The reduction process is accomplished by poling (inserting logs
into the smelt) or by introducing natural gas into the furnace.
The temperature in the furnace is maintained around 1100°C
(2010°F).
The fire-refined copper is cast into anodes, after which,
further electrolytic refining separates copper from impurities by
8-8
-------
electrolysis in a solution containing copper sulfate and sulfuric
acid. Metallic impurities precipitate from the solution and form
a sludge that is removed and treated to recover precious metals.
Copper is dissolved from the anode and deposited at the cathode.
Cathode copper is remelted and made into bars, ingots or slabs
for marketing purposes. The copper produced is 99.95 to
99.97 percent pure.
8.2 FUGITIVE EMISSION SOURCES
The potential fugitive emission sources for primary copper
smelting are shown in Figure 8-4. This figure is structured to
include all fugitive emission sources found in the industry for
the different process configurations; therefore, the figure may
include sources that are not present at all facilities. In
addition, not all sources shown are expected to be significant
sources of lead emissions. The primary fugitive dust emission
sources are paved and unpaved roads; the primary process fugitive
emission source is the converter.5'11 General descriptions of
fugitive dust sources and process fugitive sources are provided
in Sections 2.1 and 2.2, respectively. Fugitive dust and process
fugitive sources specific to the primary copper smelting process
are discussed in Sections 8.2.1 and 8.2.2, respectively.
8.2.1 Fugitive Dust
Fugitive dust 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 fugitive dust sources specific to the
primary copper smelting process are listed in Table 8-2.
As described in Section 2.1, fugitive dust sources include
paved roads, unpaved roads, and storage piles. At most primary
copper smelting facilities, the primary fugitive dust sources are
likely to be paved and unpaved roads. Haul roads to the facility
generally are paved. Within plant boundaries, both paved and
unpaved roads are common. Primary copper facilities utilize rail
to transport some ores to the site. In addition, the industry
makes extensive use of conveyers to transport the ores to
8-9
-------
00
I
LIME-
STONE
FLUX
AND
SILICA
STORAGE
RAILCAR
w w
TRAFFIC
SILICA
FLUXES
(IF REQUIRED)
FLUE DUST -
COPPER PRECIPITATES-j*
FUEL FLUX-I
REVERBERATORY
FURNACE
(SMELTER)
AIR FUEL (n)l *V
CONVERTER
* SLAG >.
MATTE
••^ (35% Cu) •:
© ^
CONVERTER
t. Unloading and handling ol ore concentrate
2. Ora concentrate storage
3. Limestone llux unloading and handling
4. Limestone llux storage
5. Roaster charging
6. Roaster leakage
7. Calcine translar
8. Charging reverberatory lumace
9. Tapping ol reverberatory
10. Reverbttralory lurnace leakage
11. Slag lapping
12. Converter charging
13. Converter leakage
14. Slag lapping from converter
IS. Blister copper tapping
16. Blister copper transfer
17. Charging blister copper to lira refining lumace
18. Copper tapping and casting
19. Slag lapping and handling
SLAG
Sll ICA AIR
FLUX OR OXYGEN
ENRICHED
AIR
(19)
ELECTHOLYTICALLY
REFINED
COPPER (>99 S% Cu)
ELECTROLYTIC
REFINING PLANT
| ^
ANODE
MUD
(IMPURITIES)
ioSO^
TAP
L-^
OB)
ANODE
CASTING
FIRE REFINING FURNACE
(ANODE FURNACE)
AIR
FLUX
(IF REQUIRED)
NATURAL
GAS
I OTHERS
(EG GREEN
IOGS)
LEGEND
- ->• POTENTIAL FUGITIVE PM SOURCE
—1>-PROCESS FLOW
Figure 8-4. Process flow diagram for primary copper smelting
showing potential fugitive PM emission points.12
-------
TABLE 8-2. PRIMARY COPPER SMELTING FUGITIVE DUST EMISSION
SOURCESa
Sources of Fugitive Dust Emissions
Material Transfer
Unloading and handling of ore concentrates
Limestone flux and silica unloading and handling
Slag pile handling and dumping
Railcar traffic
Vehicular traffic on paved and unpaved roads
Material Storage
Ore concentrate storage
Limestone flux and silica storage
aReference 12.
processes that concentrate the ores prior to entering dryers.
The storage piles most likely to have the highest levels of
fugitive lead dust emissions are the ore concentrate piles.
Storage piles generally are enclosed, and, therefore, emissions
from storage piles should be negligible. In addition, fugitive
lead may be emitted as the result of wind erosion of open areas
in and around the plant. However, the fugitive lead emissions
from these open areas are likely to be negligible in comparison
to fugitive lead emissions from road traffic.
8.2.2 Process Fugitives
The process fugitive sources for primary copper smelting are
listed in Table 8-3.
The actual quantities of lead emissions from these sources
depend on the lead content of the smelter feed, smelter operating
techniques, the type and condition of the equipment, and the
process offgas temperature. Although emissions from many of
these sources are released inside a building, ultimately they are
discharged to the atmosphere.
Another factor key to the quantity of fugitive lead
emissions released to the atmosphere is how long a process is
8-11
-------
TABLE 8-3. PRIMARY COPPER SMELTING PROCESS
FUGITIVE EMISSION SOURCES3
Process Sources of Fugitive Lead Emissions
Dryer charging
Dryer tapping
Dryer leaking
Smelting furnace charging
Smelting furnace tapping
Smelting furnace leaking
Converter charging
Converter tapping
Converter leaking
Fire refining furnace charging
Fire refining furnace tapping
Fire refining furnace leaking
Slag skimming from all furnaces
Anode casting
Flue dust handling
aReference 12.
exposed. For example, a typical single matte tapping operation
lasts from 5 to 10 minutes and a single slag skimming operation
lasts from 10 to 20 minutes. Tapping frequencies vary with
furnace capacity and type. In an 8-hour shift, matte is tapped
5 to 20 times and slag is skimmed 10 to 25 times. At times
during normal smelting operations, slag or blister copper cannot
be transferred immediately from the smelter or to the converter.
This condition, holding stage, may occur for several reasons,
including insufficient matte in the smelting furnace, the
unavailability of a crane to transfer the matte to the converter,
or others. Under these holding conditions, the converter is
rolled out of its vertical position and remains in a holding
position where fugitive emissions may result.
The converter is the most significant source of fugitive
emissions in the copper smelting operations.13 The converter may
account for as much as 80 percent of all fugitive emissions.5"11
Each of the various stages of converter operation—the charging,
8-12
-------
blowing, slag skimming, blister pouring, and holding—is a
potential source of fugitive emissions. During blowing, the
converter mouth is in stack (i.e., a close fitting primary hood
is over the mouth to capture offgases). However, fugitive
emissions may escape from the hoods. During charging, skimming,
and pouring operations, the converter mouth is out of stack
(i.e., the converter mouth is rolled out of its vertical position
and the primary hood is isolated). Fugitive emissions may be
discharged during rollout.
8.3 ESTIMATING FUGITIVE EMISSIONS
Estimating lead emissions from fugitive dust sources and'
process sources in the primary copper smelting process is
addressed in Sections 8.3.1 and 8.3.2, respectively.
8.3.1 Fugitive Dust
Estimating the fugitive emissions from unloading and
handling ore concentrates and limestone flux and silica depends
on how long the material is exposed to atmospheric conditions
(i.e., wind speed) on a given day. Fugitive lead emissions from
material handling operations from vehicles or railcars can be
estimated using the equation provided in Section 2.1.
Lead emissions from paved and unpaved roads and storage
piles generally also can be estimated using the equations
provided in Section 2.1. Because of variations from plant to
plant in the parameters used in these equations, site-specific
data should be used whenever possible to estimate fugitive dust
emissions. Section 2.1 also provides guidelines for obtaining
the data needed for the input parameters for these equations.
Sampling and analytical procedures for road dust and storage pile
samples are provided in Appendices A and B, and analytical
methods for analyzing road and storage pile material .samples for
lead are listed in Table 2-3. If plant-specific data are
unavailable, default values for many of the fugitive dust
equation parameters can be taken from the data presented in this
report. However, estimates derived using the default values
presented in this document should be used for preliminary
assessment only.
8-13
-------
To estimate lead fugitive dust emissions from paved roads
(Equation 2-2) average silt loading, the lead content of the road
dust silt fraction, average vehicle weights, and traffic volume
are required. Table 2-1 includes data on silt loadings of paved
roads at primary copper smelters. The mean silt loading reported
(292 g/m2) is considerably higher than silt loadings reported in
Table 2-1 for other industries. Therefore, there is reason to
believe that the silt loading value is conservatively high.
Table 8-4 summarizes data on the lead content of various
materials associated with primary copper smelting. In the
absence of actual data, the lead percentages listed in Table 8-4
can be used to estimate the lead silt content on roads in the
vicinity of various primary copper processes. Appendix C
provides information on weights of several industrial vehicles.
Section 2.1.1 describes methods for estimating traffic volume.
Lead fugitive dust emissions from unpaved roads can be
estimated using Equation 2-4. The input parameters for the
equation include the silt content of the road surface material;
the lead content of the silt; average vehicle speed, weight, and
number of wheels; precipitation frequency; and traffic volume.
Table 2-5 includes data on the primary copper unpaved road silt
content, which ranged from 16 to 19 g/m2 and averaged 17 g/m2. In
the absence of actual data, the lead percentages listed in
Table 8-4 can be used to estimate the lead silt content on roads
in the vicinity of various primary copper processes. Table 5-6
and Appendix C include data that can be used to estimated vehicle
weight, speed, and number of wheels. Figure 2-1 can be used to
estimate the rainfall frequency, and traffic volume can be
estimated using procedures described in Section 2.1.1.
Equations 2-6 and 2-8 can be used to estimate lead fugitive
dust emissions from storage piles. To estimate emissions related
to storage pile handling and transfer (Equation 2-6), mean wind
speed, material moisture content, and the lead content of the
silt fraction of the storage pile material are required. Mean
wind speeds are readily available from local meteorological
8-14
-------
TABLE 8-4. LEAD CONTENT OF PRIMARY COPPER SMELTING MATERIALS
Material
Concentrate
Dried concentrate
Copper matte
Blister copper
Anode
Smelting furnace slag
Electric slag cleaning furnace slag
Noranda reactor slag
Converter slag
Acid plant gas cleaning solids
Converter baghouse solids
Vent gas cleaning solids
Furnace ESP gas cleaning solids
Dryer ESP gas cleaning solids
Dryer scrubber gas cleaning solids
Electric slag cleaning furnace gas
cleaning solids
Lead content of material, percent by weight
Plant
Aa
0.15
0.135
1.12
0.07
0.07
0.46
1.96
5.9
1.5
fib
0.392
0.56
0.1
0.029
0.28
0.92
6.19
9.59
Cc
0.02
0.02
0.0024
0.005
0.21
Dd
0.045
0.045
0.12
0.03
0.0035
0.08
0.27
0.045
0.27
Ee
0.174
0.174
0.132
0.01
0.145
0.174
Ff
0.08
0.17
0.006
0.0468
0.0468
0.0021
00
I
(->
U1
aReference 5; flash furnace.
bReference 6; flash furnace.
°Reference 7; reverberatory furnace.
^Reference 8; flash furnace.
eReference 9; Noranda process reactor.
fReference 10; flash furnace..
-------
stations, and Appendix D includes data for several cities in the
United States. Table 8-4 can be used to estimate the lead
content of storage pile material. No data on storage pile
material moisture content were located in the course of this
study. To estimate wind erosion of active storage piles
(Equation 2-8), data are needed on silt content, lead content of
the silt fraction of the storage pile material, rainfall
frequency, and percentage of time that wind speed exceeds
5.4 m/sec (12 mph). Table 8-4 can be used to estimate the lead
content of the silt fraction.of the storage pile material. Data
on wind speed and rainfall frequency can be obtained from local
meteorological stations. Alternatively, Appendix D and
4
Figure 2-1 can be used to estimate these parameters. No data on
storage pile material silt content were located in the course of
this study.
8.3.2 Process Fugitives
The primary source of process fugitive lead emissions from
the primary copper smelting process is the converter operation.
Table 8-5 presents emission factors for fugitive PM emissions
from several primary copper smelting process sources. The actual
percentage of lead in the fugitive PM emissions is not known.
However, the data presented in Table 8-4 can be used to estimate
the .lead fraction of the fugitive emission sources listed in
Table 8-5.
TABLE 8-5.. FUGITIVE PM EMISSION FACTORS FOR
PRIMARY COPPER SMELTINGa
Source
Smelting furnace matte tapping
Smelting slag skimming
Converter
Anode furnace
Slag cleaning furnace
PM emission factor
kg/Mg
0.1
0.1
2.2
0.25
4
Ib/ton
0.2
0.2
4.4
0.5
8
aReference
8-16
-------
Table 8-6 presents fugitive lead emission factors for
various operations of primary copper smelters.
TABLE 8-6. FUGITIVE LEAD EMISSION FACTORS FOR
PRIMARY COPPER SMELTING3
Process
Reverberatory
Reverberatory
matte tapping3
slag skimming3
Converting13
Emission factor
kg/Mg
0.013
0.00072
0.010
Ib/ton
0.026
0.0014
0.020
aReference 1.
^References 5, 6, 8-11. Average of data presented in
Section 114 Information Collection Request responses.
8.4 CONTROLLING FUGITIVE EMISSIONS
General descriptions of fugitive dust and process fugitive
emission controls are provided in Sections 3.1 and 3.2,
respectively. Little information on measures used to control
fugitive dust emissions at primary copper smelters was obtained
in the course of this study. The information that was obtained
is summarized in the following paragraph. The remainder of the
section describes process fugitive emission controls used in the
primary copper smelting industry.
The available information indicates that primary copper
plant roads are watered at regular intervals to control fugitive
dust emissions. Emissions from storage piles generally are
controlled by enclosures.
Fugitive emissions from the primary copper smelting industry
are generally controlled by hoods or building enclosures with
exhaust ventilation systems or are collected with other process
offgases and routed to an air pollution control device. Lead
emissions are effectively removed in particulate control systems
operating at temperatures as low as 120°C (250°F). The potential
sources of fugitive PM emissions, and fugitive emission capture
and control methods are listed in Table 8-7. The current and
technically feasible control techniques are marked in Table 8-7
8-17
-------
DRAFT
ch8/leadrpc
01/05/94
TABLE 8-7. CONTROL TECHNIQUES FOR PRIMARY COPPER SMELTING
PROCESS FUGITIVE PM EMISSION SOURCES
Fugitive emissions capture ana control methods
Preventive procedures and
operating changes
Industry: Primary cooper smelting
Unloading and handling ol ore concentrates
Ore concentrate storaqe
Urnggflope f|ux unloadina and handiina
Limestone flux storage
Calcine transfer
Charqjno reverberatory furnace
Taopmg of reverberatory
Reverberatory furnace leakage
Slag tapping
Converter cnarging
Convener leakage
Blister copper tapping
Blister copper transfer
Charging blister copper to fire refining furnace
Copper tapping and casting
Slag tapping and handling
Slag pile dumping and cooling
r
r
V
V
V
•J
V
•J
•1
V
r
V
V
N
N
/
r
0
r
!<§
0
o
V
o
f
+•
r
0
/*
1
0
0
0
0
o
+
•f
+
+•
+•
M
1
0
0
0
0
o
+
*
•f
•f
*
*
+
*
/*
1
•f
*
+•
•f
+
+
+
•f
•f
+
+
+
0
0
0
0
0
•*
+
+
+•
•f
+
+
•¥
<8
I
*
/
0
0
0
0
0
Q In use control technique
* Technically feasible control technique
-------
for each potential source of fugitive emissions.
Fugitive emissions from enclosed ore crushers, smelting
furnaces, or converters can be captured with an exhaust
ventilation system equipped with an air pollution control device,
such as a dust collector.4 Air flow patterns within the building
could be controlled by the following:
1. Enclosing the smelting furnace calcine feed area;
2. Installing partitions in the roof truss area along the
converter building column lines to enclose flow from the furnace
areas;
3. Installing siding on the walls of the converter
building;
4. Installing air inlet louvers around the building
perimeter, located to provide air flow into the locations where
needed; and
5. Installing ventilating outlets at the ridge line of the
roof.M
Sometimes the fugitive emissions from one process may be combined
with offgases from other processes before entering the air
pollution control device. Typically, fugitive emissions from an
enclosed process are assumed negligible.
Secondary hood systems are used to collect fugitive
emissions from the smelt matte tapping and slag skimming
operations as well as from converters. A primary hood may
capture the exhaust and route it to an acid plant where SO2 is
recovered. A secondary hood may capture the exhaust not caught
by the primary hood and route it directly to the atmosphere or to
another control device.5'11
An air curtain capture system offers an alternative approach
for the capture of fugitives from converters without .interfering
with the normal crane-ladle operation. The air curtain is formed
by blowing air from a supply plenum or a row of nozzles that is
especially designed to form an air sheet, or curtain, with as
little turbulence as possible. This curtain is directed over the
open space, well above the converter to permit crane access. On
8-19
-------
•the opposite side of the space, the curtain and entrained air are
captured by an exhaust system. Fumes that rise from the source
are directed into the suction plenum by the curtain. Air is also
pulled into the curtain from above and below. Since all air flow
is inward, into the curtain, there is no opportunity for fumes to
escape a properly designed and operated curtain, and a high
capture efficiency is achievable.13 The effectiveness of the air
curtain in capturing fugitive emissions is greater than
90 percent.
8.5 REFERENCES
1. Compilation of Air Pollutant Emission Factors, Volume I:
Stationary Point and Area Sources, AP-42,
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, September 1993.
2. Locating and Estimating Air Emissions From Sources of
Cadmium and Cadmium Compounds, prepared by Midwest Research
Institute for U. S. Environmental Protection Agency, Office
of Air and Radiation and Office of Air Quality Planning and
Standards. September 1993.
3. Technical Report for the Phase 1 Study of Cadmium Emissions
from Primary Lead and Primary Copper Smelters, EPA Contract
No. 68-02-3817, prepared by Midwest Research Institute for
U. S. Environmental Protection Agency, September 30, 1986.
4. Control Techniques for Lead Air Emissions Volume II:
Chapter 4—Appendix B, EPA-450/2-77-012, U. S.
Environmental Protection Agency, December 1977.
5. Written Communication, T. Martin, ASARCO, Incorporated, to
B. Jordan, U. S. Environmental Protection Agency,
Section 114 Information Collection Request for the ASARCO,
Incorporated primary copper smelter in El Paso, Texas,
1993.
6. Written Communication, N. Gambell, ASARCO, Incorporated, to
B. Jordan, U. S. Environmental Protection Agency,
Section 114 Information Collection Request for the ASARCO,
Incorporated primary copper smelter in Hayden,'Arizona,
July 28, 1993.
7. Written Communication, R. Mitten, Copper Range Company, to
B. Jordan, U. S. Environmental Protection Agency,
Section 114 Information Collection Request for the Copper
Range Company primary copper smelter in White Pine,
Michigan, September 17, 1993.
8-20
-------
8. Written Communication, W. Mitchell, Pheips Dodge
Corporation, to B. Jordan, U. S. Environmental Protection
Agency, Section 114 Information Collection Request for the
Pheips Dodge Corporation primary copper smelter in Playas,
New Mexico, 1993.
9. Written Communication, F. Fox, Kennecott Utah Copper
Corporation, to R. Roberts, Utah Air Quality Board,
Section 114 Information Collection Request for the
Kennecott Utah Copper Corporation primary copper smelter in
Magna, Utah, July 27, 1993.
10. Written Communication, J. May, Magma Copper Company, to B.
Jordan, U. S. Environmental Protection Agency. Section 114
Information Collection Request for the Magma Copper Company
primary copper smelter in El Paso, Texas, July 28, 1993.
11. Written Communication, J. Humphrey, Pheips Dodge Mining
Company, to G. Grumpier, U. S. Environmental Protection
Agency, Section 114 Information Collection Request for the
Pheips Dodge Mining Company primary copper smelter in
Hurley, New Mexico, October 20, 1993.
12. Technical Guidance For Control of Industrial Process
Fugitive Particulate Emissions, EPA-450/3-77-010, prepared
by PEDCo Environmental, Inc. for U. S. Environmental
Protection Agency, March 1977.
13. Evaluation of an Air Curtain Hooding System for a Primary
Copper Converter, EPA-600/2-84-042a, prepared by PEDCo
Environmental, Inc. for U. S. Environmental Protection
Agency, December 1993.
14. Engineering Study of Fume Control for Copper Converter
Building at American Smelting and Refining Company, El
Paso, Texas, Report No. 74-50-RE, August 1974.
8-21
-------
9.0 SECONDARY COPPER SMELTING AND ALLOYING
9.1. PROCESS DESCRIPTION1'2
The secondary copper process is virtually the same as the
primary copper process; the difference is the type of impurities
removed. Large quantities of sulfur from copper ore are removed
in primary copper smelting; whereas very little sulfur needs to
be removed from secondary copper smelting, instead alloying
metals and nonmetallic contaminants are removed. In some cases
copper oxide is reduced to copper metal. The secondary copper
industry processes scrap copper of any purity, copper alloys, or
copper-bearing scrap of any copper content to produce pure
copper. Products include refined copper or copper alloys, which
are combinations of copper with materials such as tin, zinc, and
lead. For special applications, the combinations include such
metals as cobalt, manganese, iron, nickel, cadmium and beryllium,
and nonmetals such as arsenic and silicon. The products appear
in the form of ingots, wirebar, anodes, and shot.
The principal processes involved in copper recovery are
scrap metal pretreatment and pyroprocessing. Pretreatment
includes cleaning and concentrating the material prior to
entering the blast furnace. Pyroprocessing involves heating the
treated scrap to achieve separation and purification of specific
metals. Figure 9-1 is a flowchart depicting the processes that
can be expected in a secondary copper smelting operation.
Scrap metal pretreatment and pyroprocessing are discussed in
Sections 9.1.1 and 9.1.2, respectively. A list of the current
secondary copper facilities, their locations, and operational
specifics is provided in Table 9-1.2
9-1
-------
ENTERING THE SYSTEM
LEAVING THE SYSTEM
LOW-GRADE SCRAP
(SLAGS. SKIMMINGS.
BORINGS)
AIR >
PYROMETALLURGICAL
PRETREATMENT
(DRYING)
TREATED
SCRAP
GASES. DUST. METAL OXIDES
TO CONTROL EQUIPMENT
I
AIR ^
' I
BLACK
COPPER +SLAG
SMELTING FURNACE
(REVERBERATORY)
i
SEPARATED
COPPER
CARBON MONOXIDE. PARTICULATE DUST.
>• METAL OXIDES TO AFTERBURNER AND
PARTICULATE CONTROL
> _ GASES AND METAL OXIDES TO
J > CONTROL EQUIPMENT
^ SI Aft RRANMI ATPD
AND SOLD
SLAG
FLUX-
FUEL
AIR
CONVERTER
BLISTER
COPPER
AIR
FUEL
REDUCING MEDIUM,
(POUNG)
GASES. AND METAL OXIDES
' TO CONTROL EQUIPMENT
BLISTER
COPPER
i
CASTINGS AND SHOT
PRODUCTION
FUGITIVE METAL OXIDES FROM
POURING TO HOODING
SLAG
FIRE REFINING
1
GASES. METAL DUST.
' TO CONTROL DEVICE
REFINED
COPPER
Figure 9-1. Secondary copper smelting process.
1
9-2
-------
TABLE 9-1. SUMMARY OF SECONDARY COPPER SMELTERS IN THE UNITED STATES
Location
Telephone
Feed
Furnaces
Poling
Electrolytic refining
Product
Air Pollution
Control Devices
Chemetco
Hartford, IL
618-254-4381
Cu scrap
4 caldo rotary
—
Yes, but not in use
Anodes
Furnaces - 1
quencher & venturi
water scrubber
fugitives - baghouse
Cerro Copper Products
Company
St. Louis, MO
618-337-6000
#2 Cu scrap, 1 "ingot
96% Cu to anode
furnace
98 % Cu to billet furnace
2 reverb (anode &
billet): gas-fired, 250
ton capacity each
Yes, trees
Yes
Tubing
Anode - venturi water
scrubber
Billet - venturi water
scrubber
Franklin Smelters
Philadelphia, PA
215-634-2231
Cu scrap
1 blast
1 rocking reverb
2 rotary converter
Yes, trees
No
Blister Copper
Blast/Reverb/cyclon
e & baghouse
Blast - afterburner
Converter -
baghouse &
scrubber
Southwire
Carrolton, GA
404-832-5375
Cu scrap
1 blast; 1 blast
holding; 1
converter
(Hoboken); 1
anode; 1 vertical
anode shaft; & 1
anode holding
Yes, ammonia
Yes
Wire
Separate
baghouse for
blast process &
fugitive,
converter process
& fugitive
Gaston Copper
Recycling Corp.
Gaston, SC
803-796-4720
Cu scrap
1 blast
1 converter
2 reverb/anode
Yes, trees (?)
Yes
Rod
Separate baghouse
for blast process
& fugitive,
converter process
& fugitive, anode
process
vo
I
U)
Reference 2.
-------
9.1.1 Scrap Metal Pretreatment
Pretreatment of the feed material can be accomplished using
manual, mechanical, pyrometallurgical, and/or hydrometallurgical
methods. Feed scrap is concentrated by manual and mechanical
methods such as sorting, stripping, shredding, chopping (removing
insulation from wire scrap), and magnetic separation. Feed scrap
may also be briquetted in a hydraulic press to aid furnace
efficiency or reduce entrainment of fines in the dust emissions.2
Pyrometallurgical pretreatment is used and includes sweating and
drying (burning off oil and volatiles) in rotary kilns. Another
type of pretreatment is to use hydrometallurgical methods. These
methods include flotation and leaching with chemical recovery.
The aforementioned procedures may be used separately or in
combination to pretreat the feed material prior to entering the
smelting furnace.
The feed material used in the recovery process can be any
metallic scrap containing a useful amount of copper, bronze
(copper and tin), or brass (copper and zinc). Traditional forms
of scrap material are punchings, turnings and borings, ammunition
casings, defective or surplus goods; metallurgical residues such
as slags, skimmings, and drosses; and obsolete, worn out, or
damaged articles including automobile radiators, pipe, wire,
bushings, and bearings. Lead enters the secondary smelter feed
stream primarily as solder on copper pipes and radiators.
9.1.2 Pyroprocessing2
Pyroprocessing operations depend on the type and quality of
the feed material. Due to the large variety of feed materials
available, the method of operation varies greatly between plants.
Generally, a secondary copper facility deals with less pure raw
materials and produces a more refined product; whereas brass and
bronze alloy operations use cleaner scrap and need less purifying
and refining.
There are three major types of furnaces used in the
Pyroprocessing steps of secondary copper smelting: blast
furnaces (i.e., shaft or cupola furnaces), reverberatory
9-4
-------
furnaces, and converter furnaces. Blast furnaces, reverberatory
furnaces, and converter furnaces are discussed in
Sections 9.1.2.1 through 9.1.2.3, respectively.
9.1.2.1 Blast Furnaces. The blast furnace is a
vertically-oriented, refractory-lined, cylindrical shell. Air or
oxygen-enriched air is blown into the base of the furnace.
Charges are made to the top of the furnace from skip cars. The
charge contains a mixture of scrap, limestone silica (or other
slag-promoting material), and coke. The oxidation of coke and
iron (from irony scrap) supply heat to the system. Even with the
high volume of oxygen supplied to the system, coke and air is
supplied at a ratio that maintains a reducing atmosphere in the
blast furnace. Silica in the system combines with the iron oxide
to form iron-silicate slag. The resulting product, "black
copper," contains 70 to 80 percent copper and traces of zinc,
tin, iron, and nickel. The black copper and slag are transported
from the bottom of the furnace to a small reverberatory furnace
where they are separated.
9.1.2.2 Reverberatory Furnaces. The black copper and slag
mixture is continuously tapped from the blast furnace into a
small horizontally-oriented, cylindrical furnace known as the
blast holding furnace. The blast holding furnace is 'a
reverberatory furnace fired with gas or oil. The furnace allows
for a more complete separation of the black copper and slag.
Typically, slag is tapped continuously from this furnace while
metal is tapped intermittently. The black copper is tapped by
partially rotating the furnace. The molten black copper may be
charged directly to the converter or be granulated prior to
charging. Granulation is achieved by direct contact of the
molten copper with water. The resulting copper shot must be
dried prior to charging to the converter. Collected blast
furnace slags are often granulated and sold for use in roofing
shingles and in grit blasting.
9.1.2.3 Converters. The molten or granulated black copper
and excess air or oxygen are combined in a horizontally-oriented,
cylindrical furnace known as a converter. Often, gas is supplied
9-5
-------
for fuel in the initial cycle. The impurities in the slag layer
are oxidized and this process supplies sufficient heat to
maintain the furnace temperature. Blister copper, 96 percent
copper, is produced and collected slags are recycled to the blast
furnace. Following the converter furnace, metal may be charged
to a gas- or oil-fired reverberatory furnace for further
purification. The metal is cast as copper anodes, which contain
98 percent copper.
Blister copper may be poured to produce shot or castings,
but is often further refined electrolytically or by fire
refining. The fire refining process is essentially the same as
that described for the primary copper smelting industry (.see
Section 8.1.5). The sequence of events in fire refining is
(1) charging; (2) melting in an oxidizing atmosphere;
(3) skimming the slag; (4) blowing with air or oxygen until the
dioxide content reaches 0.6 percent; (5) adding fluxes;
(6) "poling," in which tree trunks are placed one at a time into
the metal bath until the dioxide content is reduced to 0.09 to
0.12 percent; (7) reskimming; and (8) pouring. Fire refining
copper may produce copper that is 99.3 to more than 99.5 percent
pure.
The final step is always casting of the alloyed or refined
metal into a desired form such as shot, wirebar, anodes,
cathodes, ingots, or other cast shapes. The metal from the melt
is usually poured into a ladle or a small pot, which serves the
functions of a surge hopper and a flow regulator, and then into a
mold. The most integrated secondary copper smelting facilities
have a casting wheel to produce anodes. Metal is transferred
from the fire refining furnace to the depressions in a horizontal
wheel. The wheel rotates as each depression is filled with anode
copper. As the casting proceeds around, it is cooled by direct
contact with collected storm water and removed.
9.2 FUGITIVE EMISSION SOURCES
The primary fugitive dust emission sources are paved and
unpaved roads; the primary process fugitive emission source is
the ladle operation in the converter stage of secondary copper
9-6
-------
smelting. General descriptions of fugitive dust sources and
process fugitive sources are provided in Sections 2.1 and 2.2,
respectively. Fugitive dust and process fugitive sources
specific to the secondary copper smelting process are discussed
in Sections 9.2.1 and 9.2.2, respectively.
9.2.1 Fugitive Dust
As described in Section 2.1, fugitive dust sources include
paved roads, unpaved roads, and storage piles. At most secondary
copper smelting facilities the primary fugitive dust sources are
likely to be paved and unpaved roads.
Table 9-2 lists the fugitive dust emission sources at a
typical secondary copper smelter. Table 9-3 presents estimated
daily lead fugitive dust emissions from paved and unpaved roads
at one secondary copper smelter. As can be seen from the table,
the primary fugitive dust sources of lead emissions are the paved
road in the vicinity of the main stack and anode storage area,
the unpaved material receiving truck trailer parking lot, and the
unpaved plant access and slag hauling road.3 Data on the
relative magnitude of lead fugitive dust emissions at other
secondary smelters could not be located during the course of this
study.
Lead fugitive dust may be emitted from the handling and
storage of feed materials and from wind erosion of open areas
around the plant. The storage piles at one secondary copper
smelter included piles of slag, sand, metallurgical dolomite,
cement copper, precipitation iron, cinders, and road salt.
Fugitive emissions from slag piles at that facility are
considered minor because of the relatively low silt content of
the slag.4 At another secondary copper smelter, the main storage
piles and stockpiles included scrap material, slag, zinc oxide,
anodes.3 However, the fugitive lead emissions from these sources
are likely to be less significant than lead emissions from roads.
9.2.2 Process Fugitives
The process fugitive sources for secondary copper smelting
are listed in Table 9-4. The actual quantities of lead emissions
9-7
-------
TABLE 9-2.
SECONDARY COPPER SMELTING FUGITIVE DUST
EMISSION SOURCES
Fugitive Dust Sources
Material Transfer
Scrap metal unloading .
Feed material transfer
Railcar traffic
Vehicular traffic on paved and unpaved roads
Material Storage
Scrap metal storage
TABLE 9-3. ESTIMATES OF LEAD FUGITIVE DUST EMISSION RATES
FROM PAVED AND UNPAVED ROADS AT ONE SECONDARY COPPER SMELTERa
Road description
Lead emissions
kg/ day (Ib/day)
Paved roads
Stack area /anode stockpile
Truck/ scale driveway
ZnO loading/baghouse access
Scrap yard
1.1 (2.5)
0.64 (1.4)
0.077 (0.17)
0.38 (0.83)
Unpaved roads
Plants access/slag hauling
Molten slag hauling
Slag hauling
Trailer haul truck parking
0.82 (1.8)
0.20 (0.44)
0.50 (1.1)
0.86 (1.9)
aReference 3.
9-8
-------
TABLE 9-4. SECONDARY COPPER SMELTING PROCESS
FUGITIVE EMISSION SOURCES
Process Fugitive Sources
Scrap metal manual and mechanical processing (sorting,
stripping, shredding, magnetic separating, and briquetting)
Scrap metal pyrometallurgical processing (sweating,
burning, drying)
Scrap metal hydrometallurgical processing (floating and
leaching)
Blast furnace charging
Blast furnace leaking
Black copper and slag tapping
Reverberatory furnace charging
Reverberatory furnace leaking
Separated copper tapping
Slag skimming
Separated copper granulating
Copper shop drying
Slag granulating
Converter charging
Converter leaking
Blister copper tapping from converter
Slag tapping from converter
Blister copper charging to refining furnace
Fire refining furnace leaking
Blister copper tapping from refining furnace
Casting
9-9
-------
from these sources depend on the lead content of the furnace
feed, smelter operating techniques, the type and condition of the
equipment, and the process offgas temperature. The charge
materials and lead content of the materials at one secondary
copper facility were reported as auto radiators (9 percent lead),
slitter scrap (less than 0.5 percent lead), and process scrap
(less than 0.25 percent lead). One source of fugitive emissions
in secondary smelter operations is charging of scrap into
furnaces containing molten metals. Fugitive emissions often
occur when the scrap being processed is not sufficiently compact
to allow a full charge to fit into the furnace prior to heating.
The introduction of additional material onto the liquid metal
surface produces significant amounts of volatile and combustible
materials and smoke, which can escape through the charging door.
The ladle transfer from the converter is the greatest source of
fugitive emissions and is the most difficult to capture and
control.4 The holding times may vary as described in
Section 8.2 ..2 for primary copper smelters.
9.3 ESTIMATING FUGITIVE EMISSIONS
The following sections discuss procedures for estimating
fugitive lead emissions from secondary copper smelters.
Section 9.3.1 addresses estimating lead emissions from fugitive
dust sources, and Section 9.3.2 addresses estimating process
fugitive lead emissions.
9.3.1 Fugitive Dust
Lead emissions from paved and unpaved roads and storage
piles can be estimated using the equations provided in
Section 2.1. Because of variations from plant to plant in the
parameters used in these equations, site-specific data should be
used whenever possible to estimate fugitive dust emissions.
Section 2.1 also provides guidelines for obtaining the data
needed for the input parameters for these equations. Sampling
and analytical procedures for road dust and storage pile samples
are provided in Appendices A and B, and analytical methods for
analyzing road and storage pile material samples for lead are
9-10
-------
listed in Table 2-3. If plant-specific data are unavailable,
default values for many of the fugitive dust equation parameters
can be taken from the data presented in this report. However,
estimates derived using the default values presented in this
document should be used for preliminary assessment only.
To estimate lead fugitive dust emissions from paved roads
(Equation 2-2), average silt loading, the lead content of the
road dust silt fraction, average vehicle weights, and traffic
volume are required. Tables 9-5 and 9-6 include data on paved
roads at two secondary copper smelters. In the absence of plant-
specific data, the information in Tables 9-5 and 9-6 can be used
to estimate silt loadings. Table 9-6 includes data on vehicle
weights at a specific facility, and Appendix C provides
information on weights of several industrial vehicles.
Section 2.1.1 describes methods for estimating traffic volume.
Lead fugitive dust emissions from unpaved roads can be
estimated using Equation 2-4. The input parameters for the
equation include the silt content of the road surface material;
the lead content of the silt; average vehicle speed, weight, and
number of wheels; precipitation frequency; and traffic volume.
Table 9-7 presents data on unpaved roads at a secondary copper
smelter. Appendix C provides information on weights of several
industrial vehicles. Figure 2-1 can be used to estimate the
rainfall frequency, and traffic volume can be estimated using
procedures described in Section 2.1.1.
Equations 2-6 and 2-8 can be used to estimate lead fugitive
dust emissions from storage piles. To estimate emissions related
to storage pile handling and transfer (Equation 2-6), mean wind
speed, material moisture content, and the lead content of the
silt fraction of the storage pile material are required. Mean
wind speeds are readily available from local meteorological
stations, and Appendix D includes data for several cities in the
United States. Table 9-8 includes data on moisture and lead
content for storage piles at two secondary copper smelters. To
estimate wind erosion of active storage piles (Equation 2-8),
data are needed on silt content, lead content of the silt
9-11
-------
TABLE 9-5. SUMMARY OF PAVED ROAD DUST SAMPLES AT A
SECONDARY COPPER SMELTER.a
Type of sampled area
Scrap yard roads A
Scrap yard roads B
Furnace yard roads
Plant access roads
Sampled
area,
m2 (ft2)
20 (215)
11.3 (122)
14.2 (153)
3.34 (36)
Material
collected,
g(lb)
42.10
(19,097)
7.54 (3,420)
5.73 (2,600)
7.64 (3,465)
Moisture,
percent
0.7-2.6
average: 1.65
1.1
1.1
0.1
Silt content,
percent
11.5-21.2
average:
15.4
17.5
12.2
6
Lead,
percent
0.92-1.55
average:
1.1
2.3
2.2
0.59
aReference 6,
TABLE 9-6. SUMMARY OF PAVED ROAD DATA FOR A
SECONDARY COPPER SMELTER3
Road
Stack area
Truck/scale driveway
Employee parking lot
ZnO loading/baghouse
access
Scrap yard
Average vehicle
weight, ton
ND
30
2
30
30
Surface dust silt,
percent
ND
17.1
0.45
10.9
17.7
Silt loading,
g/m2 -
72
24
7.84
72
4
Lead content of
silt, percent
10
7
ND
10
7
aReference 3.
ND = no data available
9-12
-------
TABLE 9-7.
SUMMARY OF UNPAVED ROAD DATA FOR A
SECONDARY COPPER SMELTERa
Road
Plant access/slag
hauling
Molten slag
hauling:
loaded vehicle
empty vehicle
Slag hauling
Trailer haul truck
parking
Surface
dust silt,
percent '
3.7
10
10
10
11
Lead content
of silt,
percent
1
1.
1
1
1
Average
vehicle speed,
mi/hr
20
5
15
10
15
Average
vehicle weight,
ton
30
95
54
30
30
Average
number of
wheels
18
8
8
18
18
aRef erejice 3
TABLE 9-8.
MOISTURE AND LEAD CONTENT FOR SECONDARY COPPER
SMELTER STORAGE PILES
Material
Moisture content, percent
Lead content, percent .
Facility Aa
Brass slag
Copper slag
Briquette fines
Cyclone fines
Briquettes
Converter slag (in furnace
yard) t
1.5-2
1.5-2
0-60, typical 15
1
10
low
ND
ND
ND
ND
ND
ND
Facility Bb
Scrap
Slag (air cooled)
Slag (wet granulated)
ZnO
8
3
20
1
7
0.57
0.57
ND
?Reference 4.
"Reference 3.
ND = no data available.
9-13
-------
fraction of the storage pile material, rainfall frequency, and
percentage of time that wind speed exceeds 5.4 m/sec (12 mph).
Data on wind speed and rainfall frequency can be obtained from
local meteorological stations. Alternatively, Appendix D and
Figure 2-1 can be used to estimate these parameters.
9.3.2 Process Fugitives2
The primary sources of process fugitive lead emissions from
secondary smelting operations are charging scrap into
pyroprocessing furnaces, furnace leaking, furnace tapping, and
the ladle transfer from the converter. .Emission factors for lead
emissions from process fugitive sources for the secondary copper
smelting process were not available. Emission rates of process
fugitives at one facility are estimated as 0.5 Ib/ton of material
charged.5 Order of magnitude estimates of fugitive lead
emissions from furnaces can be made using PM emission factors,
estimates of the capture efficiency of control devices used, and
estimates of the lead content of the scrap material charged to
the furnace. The estimated lead contents of the scrap material
used at one secondary copper facility are provided in
Section 9.2.2. Table 9-9 presents emission factors for PM. and
lead process emissions from various secondary copper smelting
furnaces.
9.4 FUGITIVE EMISSION CONTROLS
General descriptions of fugitive dust and process fugitive
emission controls are provided in Sections 3.1 and 3.2,
respectively. Methods for controlling process fugitive emissions
specific to the secondary copper smelting process are discussed
in the following paragraphs.
9.4.1 Fugitive Dust Emission Controls
For the purposes of this study, information was obtained on
measures used to control fugitive dust emissions at two secondary
copper smelters. Fugitive emission controls used at one facility
include covering or spraying storage piles with water or a
surfactant and treating all unpaved roads with water, oil, or
chemical dust suppressants. In addition, crushers, grinding
9-14
-------
TABLE 9-9. PROCESS EMISSION FACTORS FOR
SECONDARY COPPER SMELTING3
Furnace and charge type
Control
equipment
Filterable PM
kg/Mg
Ib/ton
Lead
kg/Mg
Ib/ton
Cupola
Scrap iron
Insulated copper wire
Scrap copper and brass
Reverberatory
High lead alloy (58% lead)
Red/yellow brass (15% lead)
Other alloys (7% lead)
Copper •
Brass and bronze
Rotary
Brass and bronze
Crucible and pot
Brass and bronze
Electric Arc
Copper
Brass and bronze
Electric induction
Copper
Brass and bronze
None
None
ESP
None
ESP
0.002
120
0.5
35
1.2
0.003
230
10
70
2.4
None
None
None
None
Baghouse
None
Baghouse
None
ESP
None
ESP
None
Baghouse
None
Baghouse
^Jone
Baghouse
lone
Baghouse
—
—
—
2.6
0.2
18
1.3
150
7
11
0.5
2.5
0.5
5.5
3
3.5
0.25
10
0.35
-
—
— '
5.1
0.4
36
2.6
300
13
21
1
5
1
11
6
7
0.5
20
0.7
—
—
—
—
-
—
—
-
—
—
25
6.6
2.5
-
-
-
-
—
-
-
-
-
—
—
—
—
—
—
—
50
13.2
5.0
—
-
-
—
—
-
-
—
-
—
—
—
—
—
—
—
aReference 1. Factors for high lead alloy (58 percent lead),
red and yellow brass (15 percent lead), and other alloys
(7 percent lead) produced in the reverberatory furnace are
based on unit weight produced. All other factors given in
terms of raw materials charged to unit. Dash indicates no
available information.
9-15
-------
mills, screening operations, bucket elevators, conveyor transfer
points, conveyors, bagging operations, storage bins, and truck
and rail car loading operations are sprayed with water or
surfactant solution, choke fed, or treated by another equivalent
method.4
Table 9-10 summarizes the measures used to control fugitive
dust emissions at another secondary copper facility. The
controls used for paved roads include limiting vehicle speeds,
watering, wet sweeping, applying chemical dust suppressants, and
routine inspections and repair of broken pavement where dust can
collect. Unpaved road controls used at the same facility include
limiting vehicle speeds, watering, and applying chemical dust
suppressants. Emissions from storage piles are controlled by
means of windbreaks, enclosures, watering, and minimizing drop
heights from unloading equipment.3
9.4.2 Process Fugitive Emission Controls
Fugitive lead emissions from scrap metal pretreatment
processes can be controlled by totally enclosing the process,
adding primary or secondary hoods, or adding curtains that help
direct fugitive emissions into the hood. Curtains increase the
capture efficiencies of primary and secondary hoods.
One facility utilizes a lead sweating operation to remove and
recover the lead prior to smelting.
Fugitive emissions from the fractional charging of scrap to
furnaces can be avoided by briquetting the charge. When
fractional charging cannot be eliminated, fugitive emissions are
reduced by turning off the furnace burners during charging. This
reduces the flow of exhaust gases and enhances the ability of the
exhaust control system to handle the emissions. Typically, lead
contained in the scrap copper feed is converted to the oxide form
in the smelter furnaces and expelled with the exhaust gas stream.
The resulting fumes are captured in the process baghouses and
represent a saleable byproduct. The processing to recover the
metal content from the flue dust is done by outside firms.
9-16
-------
TABLE 9-10. SUMMARY OF FUGITIVE DUST CONTROLS AT
A SECONDARY COPPER SMELTER3
Source
Controls
Paved roads
Stack area
Truck/scale driveway
Employee parking lot
ZnO loading/baghouse access
Scrap yard
Vehicle speeds limited
Water spraying before anode hauling
Hourly wetting after anode hauling
Wet sweeping daily
Careful handling of baghouse dust
Pavement routinely inspected and repaired
Chemical dust suppressant applied routinely
.Wet sweeping daily
Routine sweeping
Chemical dust suppressant applied routinely
Water flushing
Wet sweeping daily
Vehicle speeds limited
Wet sweeping daily
Unpaved roads
Plant access/slag hauling
Molten slag hauling
Slag hauling
Trailer haul truck parking
Vehicle speeds limited
Chemical dust suppressant applied routinely
Vehicle speeds limited
Water spraying once daily
Vehicle speeds limited
Chemical dust suppressant applied routinely
Chemical dust suppressant applied routinely
Storage piles
Scrap
Slag (air cooled)
Slag (wet granulated)
ZnO
Minimize drop height
Wetting 3,000 gal/3 hours
Wetting 3,000 gal/3 hours
Windbreaks
Wetting
aReference 3.
9-17
-------
Fugitive emissions from the furnaces can be controlled by
enclosing the process, capturing the exhaust gases, and routing
them through an air pollution control device. One secondary
copper facility has a baghouse on the blast and converter
furnaces to collect process emissions. A second baghouse has
been added to collect the fugitive emissions. Another secondary
copper smelter has a hygiene system that collects fugitive
emissions with hoods placed at certain points, such as the charge
door hood, launder transfer, and holding furnace tap door. Gases
are then routed to the baghouse, filtered, and exhausted through
the stack.5 Operation and maintenance plans for the furnaces can
also reduce the amount of fugitive emissions from furnace
ma1functions.
The converter furnace may exhaust to a baghouse. Fugitive
emissions are collected by a small hood over the charge/tap
opening. Process emissions and collected fugitives are sent to
the same baghouse.5 Tapping furnaces at the lowest possible
melting temperature, or adding fixed or movable hoods over these
operations will also reduce fugitive lead emissions.
The slag from the blast furnace may be sold as a byproduct.
It is granulated for use as an abrasive or as a component of
building materials such as asphalt shingles.
9.5 REFERENCES FOR CHAPTER 9
I. Compilation of Air Pollutant Emission Factors, Volume I:
Stationary Point and Area Sources, AP-42, U. S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
September 1993.
2. Written Communication, J. Portzer, Research Triangle
Institute, to E. Grumpier, U. S. Environmental Protection
Agency, Research Triangle Park, NC, Secondary Copper Draft
Report, Information Gathering for Standards of Performance
for Hazardous Air Pollutants from Primary Copper Smelters.
EPA Contract No. 68-D1-0118. July 13, 1993.
3. Written Communication, M. Martin, Illinois Environmental
Protection Agency, to R. Marinshaw, Midwest Research
Institute, Information on Lead Processes and Emissions for
Chemetco, Incorporated, Hartford, Illinois, December 14,
1993.
9-18
-------
4. Written Communication, M. Martin, Illinois Environmental
Protection Agency, to R. Marinshaw, Midwest Research
Institute, Information on Lead Processes and Emissions for
Cerro Copper, Sauget, Illinois, December 14, 1993.
5. Written Communication, L. Hollar, Research Triangle
Institute, to G. Street, U. S. Environmental Protection
Agency, Research Triangle Park, NC, Southwire Company trip
report, Preliminary Source Assessment for the Secondary
Copper Smelting Industry, EPA Contract 68-D10118; May 19,
1993.
6. Written Communication, R. Scott, Philadelphia Department of
Health, Philadelphia, Pennsylvania, to M. Ramsey, Midwest
Research Institute, Information on Fugitive Dust Emissions at
a Secondary Copper Smelter, October 7, 1993.
7. Control Techniques for Lead Air Emissions Volume II:
Chapter 4 - Appendix B, EPA-450/2-77-012, U. S. Environmental
Protection Agency, December 1977.
9-19
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10.0 SECONDARY ZINC SMELTING
10.1 PROCESS DESCRIPTION1
The secondary zinc industry processes scrap metals for the
recovery of zinc in the form of zinc slabs, zinc oxide, or zinc
dust. As of 1991, there were 12 secondary zinc recovery plants
operating in the United States. Production in 1991 was
229,621 metric tons.2 The secondary zinc facilities and their
locations are listed in Table 10-1.
In addition to these traditional secondary zinc facilities,
a number of plants process EAF dust from steel plants to recover
zinc. In 1991, there were nine such facilities operating in the
United States. These facilities also are listed in Table 10-1.
Zinc recovery from scrap metal involves three general
operations performed on scrap, (1) pretreatment, (2) melting, and
(3) refining. Processes typically used in each operation are
shown in Figure 10-1 and are described in the following
paragraphs. Following the description of this traditional
secondary zinc process, a description of the process by which
zinc is recovered from steel plant EAF dust is provided.
10.1.1 Scrap Pretreatment
Scrap metal is delivered to the secondary zinc processor as
ingots, rejected castings, flashing, and other mixed metal scrap
containing zinc. Scrap pretreatment includes: (1) sorting,
(2) cleaning, (3) crushing and screening, (4) sweating, and
(5) leaching.
In the sorting operation, zinc scrap is manually separated
according to zinc content and any subsequent processing
requirements. Cleaning removes foreign materials to improve
10-1
-------
TABLE 10-1. SECONDARY ZINC FACILITIES
Facility name
Location
Secondary zinc plants
Arco Alloys Corp.
W.J. Bullock, Inc.
T.L. Diamond & Co. , Inc.
Florida Steel Co.,
Gulf Reduction Corp.
Hugo Neu-Proler Co.
Huron Valley Steel Corp.
Indiana Steel & Wire Co., Inc.
Interamerican Zinc, Inc.
Nucor Yamato Steel Co.
The River Smelting & RFC Co.
Zinc Corp. of America
Detroit, MI
Fairfield, AL
Spelter, WV
Jackson , TN
Houston , TX
Terminal Island, CA
Belleville, MI
Muncie, IN
Adrian, MI
Blytheville, AR
Cleveland, OH
Palmerton, PA
Steel plant EAF dust processing plants
Florida Steel Co.
Hprsehead Development
Resource Co., Inc.
Horsehead Development
Resource Co. , Inc.
Horsehead Development
Resource Co., Inc.
Horsehead Development
Resource Co. , Inc.
Laclede Steel Co.
North Star Steel Corp.
Nucor-Yamamoto Steel Co.
Zia Technology of Texas, Inc.
Jackson , TN
Calumet City, IL
Monaca , PA
Palmerton, PA
Rockwood, TN
St. Louis, MO
Beaumont , TX
Blytheville, AR
Caldwell, TX
eference 2.
10-2
-------
REFINING/ALLOYING
PRETHEATMENT
OTHER
MIXED
SCRAP
CLEAN
SCRAP'
ZINC ALLOYS
CONTAMINATED
ZINC OXIDE '
BAGHOUSE DUST
RESIDUES
SKIMMINGS
SWEATED
SCRAP (MELT
OR INGOT)
Figure 10-1. Secondary zinc recovery process.1
-------
product quality and recovery efficiency. Crushing facilitates
the ability to separate the zinc from the contaminants. Screening
and pneumatic classification concentrate the zinc metal for
further processing.
A sweating furnace (i.e., kettle [pot], rotary,
reverberatory, muffle, or electric furnace) slowly heats the
charged scrap containing zinc and other metals to approximately
364°C (787°F). This temperature is sufficient to melt zinc but
is still below the melting point of the remaining metals. The
charge to the scrap may be worked by agitation or stirring during
melting, and chloride flux may be present either as residual
flux, in charged residual scrap, or as flux added to the charge.
Working and fluxing of the charge are done to help effect the
desired metal separation. Molten zinc collects at the bottom of
the sweat furnace and is subsequently recovered. The molten zinc
may be (1) fed directly to another furnace for further
processing, (2) fed directly to a refining furnace, or
(3) sampled and analyzed, then alloyed by adding metals to obtain
the specified composition, and then cast as ingots. The non-
metallic residues, along with some platings, form on the molten-
metal bath surface and are skimmed off. The remaining scrap
metal is cooled and removed to be sold to other secondary
processors.
Leaching with sodium carbonate solution converts dross and
skimmings to zinc oxide, which can be reduced to zinc metal. The
zinc containing material is crushed and washed with water,
separating contaminants from zinc-containing metal. The
contaminated aqueous stream is treated with sodium carbonate to
convert zinc chloride into sodium chloride (NaCl) and insoluble
zinc hydroxide (ZnOH). The NaCl is separated from the insoluble
residues by filtration and settling. The precipitate zinc
hydroxide is dried and calcined (dehydrated into a powder at high
temperature) to convert it into crude zinc oxide (ZnO). The ZnO
product is usually refined to zinc at primary zinc smelters. The
washed zinc-containing metal portion becomes the raw material for
the melting process.
10-4
-------
10.1.2 Melting
Zinc scrap is melted in kettle, crucible, reverberatory, and
electric induction furnaces. Flux is used in these furnaces to
trap impurities from the molten zinc. Facilitated by agitation,
flux and impurities float to the surface of the melt as dross,
which is skimmed from the surface. The remaining molten zinc may
be poured into molds or transferred to the refining operation in
a molten state.
Zinc alloys are produced from pretreated scrap during the
sweating and melting processes. The alloys may contain small
amounts of copper, aluminum, magnesium, iron, lead, cadmium, and
tin. Zinc alloys containing 0.65 to 1.25 percent copper are
significantly stronger than unalloyed zinc.
10.1.3 Refining
Refining processes further remove impurities in clean zinc
alloy scrap and in zinc vaporized during the melt phase in retort
furnaces, as shown in Figure 10-2, or in muffle furnace systems,
shown in Figure 10-3. Molten zinc is heated until it vaporizes.
Zinc vapor is condensed and recovered in several forms, depending
upon temperature, recovery time, absence or presence of oxygen,
and the type of equipment used during zinc vapor condensation.
Final products from refining processes include zinc ingots, zinc
dust, zinc oxide, and zinc alloys.
10.1.3.1 Retort Furnaces. Distillation retorts and
furnaces are used either to reclaim zinc from alloys or to refine
crude zinc. Bottle retort furnaces consist of a pear-shaped
ceramic retort (a long-necked vessel used for distillation).
Bottle retorts are filled with zinc alloys and heated, sometimes
as long as 24 hours, until most of the zinc is vaporized.
Distillation involves vaporization of zinc at temperatures from
982°C to 1249°C (1800°F to 2280°F) and condensation as zinc dust
or liquid zinc. Zinc dust is produced by vaporization and rapid
cooling, and liquid zinc results when the vaporous product is
condensed slowly at moderate temperatures. The melt is cast into
ingots or slabs.
10-5
-------
IMPURE
METAL
CHARGE
CERAMIC
CONDENSER
SPEISS
HOLE
SEAL
BURNER
PORT
H
T
\
I
Ml
u
111
PURE
METAL
TAPHOLE
Figure 10-2. Zinc retort distillation furnace.1
STACK
MOLTEN METAL
TAPHOLE
MOLTEN METAL
FLAME PORT AIR IN
DUCT FOR OXIDE
COLLECTION
RISER CONDENSER
UNIT
J
MOLTEN METAL
TAPHOLE
Figure 10-3. Muffle furnace and condenser.1
10-6
-------
10.1.3.2 Muffle Furnaces. A muffle furnace is a
continuously charged retort furnace, which can operate for
several days at a-time. Molten zinc is charged through a feed
well that also acts as an airlock (vaporizing unit). From the
vaporizing unit,.the vaporized zinc is channeled to the condenser
where it is condensed to liquid metal. Muffle furnaces generally
have a much greater vaporization capacity than bottle retort
furnaces. Periodically, the molten zinc is tapped from the
condenser and cast into ingots. Both zinc ingots and zinc oxide
of 99.8 percent purity are produced.
Pot melting, unlike bottle retort and muffle furnaces, does
not incorporate distillation as a part of the refinement process.
This method merely monitors the composition of the intake to
control the composition of the product. Specified die-cast
scraps containing zinc are melted in a steel pot. Pot melting is
a simple indirect heat melting operation where the final alloy
cast into zinc alloy slabs is controlled by the scrap input into
the pot.
Furnace distillation with oxidation produces zinc oxide
dust. These processes are similar to distillation without the
condenser. Instead of entering a condenser, the zinc vapor
discharges directly into an air stream leading to a refractory-
lined combustion chamber. Excess air completes the oxidation and
cools the zinc oxide dust before it is collected in a fabric
filter.
Zinc oxide is transformed into zinc metal though a retort
reduction process using coke as a reducing agent. Carbon
monoxide produced by the partial oxidation of the coke reduces
the zinc oxide to metal and carbon dioxide. The zinc vapor is
recovered by condensation.
10.1.4 Steel Plant EAF Dust Processing2-3
Zinc can be recovered from steel plant EAF dust using
several processes, including the plasma, Waelz, flame reactor,
Elkem, and inclined rotary processes. The following paragraphs
10-7
-------
describe the Waelz process, which, in terms of annual production
of recovered zinc, is the predominant method used domestically.
Steel plant EAF dust is transported to the plant and stored
in enclosed storage piles. The lead content of EAF dust varies
between 0.001 percent and 32 percent by weight; the latter end of
the range pertains to dust generated in the manufacture of
specialty steels. The average lead content of EAF dust processed
by one facility was reported as 1.51 percent by weight.3
The material is charged to a weigh hopper and conveyed with
crushed coal or petroleum coke to the Waelz kiln. The included
rotary kiln is charged with the crushed coal/EAF charge. As the
charge is heated in the kiln, oxides of arsenic, cadmium, and
lead are volatilized and collected in a fabric filter. This
material is referred to as steel fume oxide. The nonvolatile
portion of the feed material empties out of the lower end of the
kiln and is called iron-rich material.
The steel fume oxide is fed to a calciner, in which more
impurities are driven off and collected in a fabric filter. This
volatilized material consists largely of lead oxide. The
nonvolatile portion of the calciner feed, known as steel fume
oxide, exits the lower end of the calciner. This material is
approximately 60 percent zinc.
10.2 FUGITIVE EMISSION SOURCES1'3-*
The potential fugitive emission sources for secondary zinc
processing of scrap metal are shown in Figure 10-4. Emission
sources and controls corresponding to the numbers in the figure
can be found in Table 10-5. This figure is intended to be
inclusive of all fugitive emission sources; therefore, may
include sources that are not present at all facilities. In
addition, many of the sources shown may not be significant
sources of lead emissions. The primary fugitive dust emission
sources are paved and unpaved roads; the process fugitive
emission sources include crushing and screening operations,
furnace charging, leakage, and tapping. General descriptions of
fugitive dust sources and process fugitive sources are provided
10-8
-------
O
I
VO
BAnilOUSF.DIIM
REVERBF.RATORY
SWF.AT
FUKNACE
KETTLE (POT)
SWEAT
FURNACE
ROTARY
SWEAT
FURNACE
MUFFLE SWEAT
FURNACE
ELECTRIC
RESISTANCE
SWIiAT
FURNACE
CRUCIBLE
MELTING
R.IRNACE
KETTLE (POT)
MELTING
FURNACE
REVERBERATORY
MULTING
FURNACE
ELECTRIC
INDUCTION
MELTING
FURNACE
MUFH.E
DISTILLATION CONDIiNSOR
FURNACE
ALLOYING
CASTINC,
LEGEND
^ POTENTIAL PM SOURCE
> HKCM'HSSH.OW
Figure 10-4. Process flow diagram for secondary zinc production
showing potential fugitive dust and process fugitive
PM emissions points.4
-------
in Sections 2.1 and 2.2, respectively. Fugitive dust and process
fugitive sources specific to the secondary zinc process are
discussed in Sections 10.2.1 and 10.2.2, respectively.
10.2.1 Fugitive Dust
The fugitive dust sources specific to the secondary zinc
process are listed in Table 10-2. As described in Section 2.1,
fugitive dust sources include paved roads, unpaved roads, and
storage piles. Little information on fugitive dust emission
sources was obtained on secondary zinc processing facilities in
the course of this study. However, at most secondary zinc
processing facilities, the primary fugitive dust sources are
likely to be paved and unpaved roads.
TABLE 10-2. SECONDARY ZINC FUGITIVE DUST EMISSION SOURCES
Fugitive dust sources
Material transfer
Scrap material unloading
Railcar traffic
Vehicular traffic on paved and unpaved roads
Material storage
Flue dust handling and storage
Metal residue storage
Alloy materials storage
Scrap metal storage
The paved roads most likely to have the highest levels of
fugitive emissions are the haul roads to the plant and roads used
to transport scrap and waste materials from storage areas to the
process units. Fugitive dust may be emitted from the handling
and storage of feed materials and from wind erosion of open areas
around the plant. Based on the available information, however,
10-10
-------
the lead content of scrap materials processed at these facilities
is negligible.4 Therefore, it is very likely that fugitive lead
emissions from these sources are negligible.
The primary fugitive lead dust sources at EAF dust
processing plants are likely to be roads on which the EAF dust is
transported to the plant and roads associated with the removal
and transport of dust collected from the calciner fabric filter.
10.2.2 Process Fugitives4
The process fugitive sources for secondary zinc processing
are listed in Table 10-3.
TABLE 10-3. SECONDARY ZINC PROCESS FUGITIVE
EMISSION SOURCES
Process fugitive sources
Scrap metal pretreatment (sorting, cleaning, crushing and
screening, etc.)
Scrap metal pyroprocessing (sweating, leaching)
Sweat furnace charging
Sweat furnace leakage
Sweat furnace tapping
Melting furnace charging
Melting furnace leakage
Melting furnace tapping
Slag/dross tapping
Distillation furnace charging
Distillation furnace leakage
Condenser upsets
Alloying
Casting
Data from earlier studies reports the lead content of two
fugitive PM samples from a sweat furnace as 0.14 and 0.16 percent
by weight.4 However, more recent information on three secondary
zinc facilities indicates that the lead content of scrap material
processed at these facilities is negligible; at one facility the
composition of scrap material includes 0.2 percent impurities,
which consists of copper, lead, cadmium, and magnesium.5'6
10-11
-------
Therefore, the fugitive lead emissions from secondary zinc
processing also are likely to be negligible.
Little information is available on process fugitive lead
emissions from steel EAF dust processing plants. However,
fugitive lead emissions from kilns and calciners are potentially
significant.
10.3 ESTIMATING FUGITIVE EMISSIONS
The following sections discuss procedures for estimating
fugitive lead emissions from various secondary zinc processing
sources. Section 10.3.1 addresses estimating lead emissions from
fugitive dust sources, and Section 10.3.2 addresses estimating
process fugitive lead emissions.
10.3.1 Fugitive Dust
Fugitive dust emissions from paved and unpaved roads and
storage piles can be estimated using the equations provided in
Section 2.1. Because of variations from plant to plant in the
parameters used in these equations, site-specific data should be
used whenever possible to estimate fugitive dust emissions.
Section 2.1 also provides guidelines for obtaining the data
needed for the input parameters for these equations. Sampling
and analytical procedures for road dust and storage pile samples
are provided in Appendices A and B, and analytical methods for
analyzing road and storage pile material samples for lead are
listed in Table 2-3. If plant-specific data are unavailable,
default values for many of the fugitive dust equation parameters
can be taken from the data presented in this report. However,
estimates derived using the default values presented in this
document should be used for preliminary assessment only.
To estimate lead fugitive dust emissions from paved roads
(Equation 2-2), average silt loading, the lead content of the
road dust silt fraction, average vehicle weights, and traffic
volume are required. Tables 2-1, 4-3, 5-4, 5-5, 9-5, and 9-6
include data on silt loadings of paved roads for a number of
industrial facilities. In the absence of plant specific data,
the information in these tables can be used to estimate silt
loadings. Data on the lead content of road silt were not
10-12
-------
available for secondary zinc facilities, and the available data
indicate that the lead content is likely to be negligible.
Therefore, only site-specific data should be used to estimate the
lead content of paved road dust at secondary zinc facilities.
Appendix C provides information on weights of several industrial
vehicles, and Section 2.1.1 describes methods for estimating
traffic volume.
Lead fugitive dust emissions from unpaved roads can be
estimated using Equation 2-4. The input parameters for the
equation include the silt content of the road surface material;
the lead content of the silt; average vehicle speed, weight, and
number of wheels; precipitation frequency; and traffic volume.
No data were available on secondary zinc processing plant unpaved
road dust. However, Tables 2-5, 4-3, and 9-7 include data on the
unpaved road silt content for a number facilities. Because the
available data indicate that the lead content of secondary zinc
feed materials is likely to be negligible, only site-specific
data should be used to estimate the lead content of unpaved road
dust at secondary zinc facilities. Table 5-6 and Appendix C
include data that can be used to estimated vehicle weight, speed,
and number of wheels. Figure 2-1 can be used to estimate the
rainfall frequency, and traffic volume can be estimated using
procedures described in Section 2.1.1.
Equations 2-6 and 2-8 can be used to estimate lead fugitive
dust emissions from storage piles. To estimate emissions related
to storage pile handling and transfer (Equation 2-6), mean wind
speed, material moisture content, and the lead content of the
silt fraction of the storage pile material are required. Mean
wind speeds are readily available from local meteorological
stations, and Appendix D includes data for several cities in the
United States. No data on storage pile material moisture and
lead content were located in the course of this study. The only
available data indicate that the lead content of storage pile
materials is negligible. Therefore, only site-specific data
should be used to estimate the lead content of storage pile
material silt. To estimate wind erosion of active storage piles
10-13
-------
(Equation 2-8), data are needed on silt content, lead content of
the silt fraction of the storage pile material, rainfall
frequency, and percentage of time that wind speed exceeds
5.4 m/sec (12 mph). Data on wind speed and rainfall frequency
can be obtained from local meteorological stations.
Alternatively, Appendix D and Figure 2-1 can be used to estimate
these parameters.
10.3.2 Process Fugitives
The primary sources of process fugitive lead emissions from
the secondary zinc processing sources are likely to be scrap
metal pretreatment,.furnace charging, furnace leaking, furnace
tapping, condenser upsets, alloying, and casting. Emission
factors for PM emissions from secondary zinc smelting are
summarized in Table 10-4. Emission factors for lead emissions
from process fugitive sources for the secondary zinc process are
likely to be negligible Emission factors for fugitive emissions
from steel EAF dust processing plants were not available.
10.4 CONTROLLING FUGITIVE EMISSIONS3'4
General descriptions of fugitive dust and process fugitive
emission controls are provided in Sections 3.1 and 3.2,
respectively. The potential sources of fugitive PM emissions,
and fugitive emission capture and control methods are listed in
Table 10-5.2 Based on a 1975 study, the control techniques in
use at the time of the study and other technically feasible
control techniques are indicated in Table 10-5 for each potential
source of fugitive emissions. Little information is available on
methods used to control fugitive dust emissions at secondary zinc
processing plants. However, the controls described in
Section 3.1 generally should be applicable to these facilities.
Information obtained from one steel EAF dust processing plant
indicates that fugitive dust control measures in practice include
monthly sweeping of paved roads; application of an asphalt-based
dust suppressant on unpaved roads as required; control of plant
traffic entry; water spraying of conveyor transfer points; and
water spraying of crushing and screening operations. In
10-14
-------
Table 10-4.
FUGITIVE PARTICULATE EMISSION FACTORS
SECONDARY ZINC SMELTING*
FOR
Emission source
Reverberatory sweating13
Rotary sweating1*
Muffle sweating13
Kettle (pot) sweating13
Electrical resistance' sweating, per kg
processed13
Crushing/ screening0
Sodium carbonate leaching
Kettle (pot) melting furnace13
Crucible melting furnaced
Reverberatory melting furnace13
Electric induction melting13
Alloying retort distillation
Retort and muffle distillation
Casting13
Graphite rod distillation
Retort distillation/oxidation
Muffle distillation/oxidation
Retort reduction
Emission factor
kg/Mg
0.63
0.45
0.54
0.28
0.25
2.13
ND
0.0025
0.0025
0.0025
0.0025
ND
1.18
0.0075
ND
ND
ND
ND
Ib/ton
1.3
0.90
1-1
0.56
0.50
4.3
ND
0.005
0.005
0.005
0.005
ND
2.4
0.015
ND
ND
ND
ND
aReference 1. ND = no data.
^Estimate based on stack emission factor, assuming fugitive
emissions to be equal to five percent of stack emissions.
GAverage of reported emission factors.
^Engineering judgment, assuming fugitive emissions from
crucible melting furnace to be equal to fugitive emissions.
from kettle (pot) melting furnace.
10-15
-------
DRAFT
chll/leadrpt
12/29/93
TABLE
lXL-
CONTROL TECHNIQUES FOR SECONDARY ZINC PROCESS
' FUGITIVE EMISSION SOURCESa
Fugitive emissions capture ana control metnoas
Preventive
procedures and
'operating enanqes/
Capture
metnoas
/Removal /
equipment • /
<*
Industry Secondary Zinc Production
1 Crushing/screening of residue skimmings
2. Reverberatory sweat tumace
2a. Charging
2b. Tapoing
3. Kettle (pot) sweat furnace
3a. Charging
3b Tapping
* Rotary sweat tumace
4a Charging
4b Tapping
5. Muffle sweat furnace
5a. Charging
So. Tapping
6 Electnc resistance sweat furnace
6a. Charging
6b Tapping
7 Hot metal transfer to melting furnace
8 Cruable melting tumace
3a. Charging
3D Tapping
9 Kettle (pot) melting furnace
9a Charging
9b Tapping
IM
0
//
0
h
0
0
0
0
0
0
0
0
0
0
0
0
0
0
r
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
//
0
0
0
0
0
0
0
0
0
0
0
0
0
0
r
*
*
^
:
•*.
+
*
+
I
r
a
0
0
0
0
0
0
0
0
0
0
*
0
0
0
0
• / t
i *
*
Uj
0 i use control technique
- Technically feasible control technique
.-16
-------
DRAFT
chll/leadrpt
12/29/93
TABLE /1-5. (continued)
Fugitive emissions capture and control methods
Preventive
| procedures and
operating changes/
/Capture / Removal /
methods / equipment /
10. Reveroeratory melting furnace
I0a Charging
10b Tapping
11 . Electric induction melting furnace
11 a. Charging
lib. Tapping
12. Hot metal transfer to retort or alloying
13. Distillation retort and condenser
1 3a. Charging distillation retort
1 3b. Leakage between retort and condenser
1 3c. Upset in condenser
13d. Tapping
14 Muffle distillation furnace and condenser
1 4a. Charging muffle distillation furnace
1 4b. Leakage between furnace and condenser
I4c. Upset in condenser
I4d. Tapping
15. Alloying
16. Casting
1 03
0
0
' •*
0
0
' •*
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
+
•f
0
0
0
0
0
0
0
0
0
b
0
0
•f
•f
+
+
•f
•f
•f
+
+
+
+
+
•f
-»•
+
+
+
0
0
0
0
•f
0
0
0
0
0
0
0
0
-f
+
0 In use control technique
4- Technically feasible control technique
aReterence 2.
1-17
-------
addition, some States require material handling and storage
operations be performed in a totally enclosed area, and fugitive
emissions from these sources can be assumed to be negligible.5
Process fugitives from crushing and screening operations can
be recovered by hooded exhausts used as capture devices and then
controlled with air pollution control devices such as fabric
filters. Although, better control of operating parameters and
procedures such as proper feed rates, operating machinery only
when required, and following proper maintenance schedules will
help alleviate fugitive emissions from crushing/screening
operations.
Fugitive emissions from the various sweating and melting
furnaces can all be controlled in basically the same way. If
primary control systems already are installed, fugitive emission
rates can be reduced by increasing exhaust flow rates. Fixed or
movable hoods over the furnaces are very effective in controlling
fugitive emissions. These hoods are usually very effective if
placed over charging and even more effective if placed over
tapping areas. A capture velocity of 0.5 to 1.0 meters/second
(100 to 200 ft/min) is usually adequate for controlling fugitive
emissions.
Distillation and condensation operations can be controlled
in the same manner. Improved maintenance and construction
materials will help prevent fugitive emissions from escaping from
the connection between the distillation unit and the condenser.
Alloying and casting operations can be controlled by the use
of fixed or movable hoods over the areas involved or by building
evacuations to a baghouse. Curtains that direct emissions into
hoods are also effective control measures. During casting
operations, several steps can be taken to prevent the generation
of fugitive emissions. As long as the temperature of the molten
zinc is kept below 590°C (1100°F) and mold release compounds do
not contain oils or other volatiles, few fugitive emissions will
be generated.
10.5 REFERENCES FOR CHAPTER 10
10-18
-------
1. Compilation of Air Pollutant Emission Factors, Volume I:
Stationary Point and Area Sources, AP-42,
U. S. Environmental Protection Agency, Research Triangle
Park, North Carolina, September 1993.
2. Jolly, James H, Zinc, 1991 Annual Report, U. S. Department
of the Interior, Bureau of Mines, Washington, D.C.,
December 1992.
3. Written communication, M. Martin, Illinois Environmental
Protection Agency, to R. Marinshaw, Midwest Research
Institute, Information on processes and emissions for the
Horsehead Resource Development Company, Inc., Calumet,
Illinois, December 22, 1993.
4. Technical Guidance For Control of Industrial Process
Fugitive Particulate Emissions, EPA-450/3-77-010, prepared
by PEDCo Environmental, Inc. for U. S. Environmental
Protection Agency, March 1977.
5. Facsimile from M. Maillard,, Air Quality Division, Michigan
Department of Natural Resources, to R. Marinshaw, Midwest
Research Institute, Information on Interamerican Zinc,
Incorporated, Adrian, Michigan, November 30, 1993.
6. Telephone communication from Q. Baig, Wayne County Health
Department, Detroit, Michigan, to R. Marinshaw, Midwest
Research Institute, Information on Arco Alloys Corporation,
Detroit, Michigan, and Huron Valley Steel Corporation,
Belleville, Michigan, December 14, 1993.
10-19
-------
11.0 SOLDER AND AMMUNITION MANUFACTURING
This section describes fugitive emission sources and
controls for lead-based solder and ammunition manufacturing.
Solder and ammunition manufacturing plants can be classified
generally as lead rerneIting facilities, and many of the processes
in both industries are similar. During the course of this study,
little information was collected on ammunition manufacturing;
most of the material presented in this section is based on
information obtained on the solder manufacturing industry.
However, a number of lead remelting facilities produce both
solder and ammunition in addition to other lead-based products,
and sources and emissions for both solder and ammunition
manufacturing are likely to be comparable.
11.1 PROCESS DESCRIPTION
Process descriptions for solder manufacturing and ammunition
manufacturing are presented below in Sections 11.1.1 and 11.1.2,
respectively.
11.1.1 Solder Manufacturing1'5
Lead-based solder is manufactured using tin and lead, and
sometimes includes other metals such as antimony and silver. In
general, virgin metals are used, but solder also may be produced
from scrap materials. Solder generally can be classified
according to the manufacturing process as either extruded/cast
solder or paste solder. Extruded/cast solder is manufactured by
melting solder alloys in kettles and then either casting the
molten material into solder ingots or extruding or stamping the
molten material. Paste solder is manufactured by mixing alloys
with resins to form a paste. Paste solder generally is used in
ll-l
-------
the production of electronic circuit boards. Typical alloys used
to manufacture solder include 5 to 63 percent tin, up to
5 percent antimony and silver, and 37 to 95 percent lead.
Table 11-1 lists the facilities that were the major domestic
consumers of lead for solder in 1987. Six of these facilities
accounted for 76 percent of 19,758 Mg (21,734 tons) of lead used
to manufacture solder in 1987. Domestic consumption of lead for
solder and ammunition in 1992 totalled 6,006 Mg (6,607 tons) and
51,542 Mg (56,696 tons), respectively.6
Some solder manufacturing facilities produce only cast
solder ingots, whereas other facilities may manufacture cast
solder, extruded and stamped solder, and solder paste.
Facilities that manufacture solder may also produce other cast
lead products such as shot for ammunition and lead sheathing, in
addition to cast products of other alloys. The.manufacturing
processes for cast/extruded solder and paste solder are described
in more detail in Sections 11.1.1.1 and 11.1.1.2, respectively.
11.1.1.1 Cast/Extruded Solder Production. Tin and lead are
weighed out in the desired amounts and are melted in melting
kettles. Melting kettle temperatures range from 182° to 482°C
(360° to 900°F), but generally are maintained no higher than
about 371°C (700°F), depending on the composition of the alloy.
The melting point of lead is 327°C (621°F). The melting
temperature of the alloy decreases as the amount of tin in the
alloy increases. The melting process used in the manufacture of
solder is similar to the grid casting step used in lead acid
battery manufacturing, which is described in Section 6.1.1 of
this report.
Once the alloy is molten, small amounts of antimony and
silver can be added, and these small amounts dissolve in the
molten alloy even though the alloy temperature is well below the
melting point of these two metals. After the desired alloy is
produced, the molten metal is poured into a mold or transferred
to an extruder. Depending on its size, the melting kettles may
be turned (emptied) 4 to 6 times per hour. The molten material
11-2
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TABLE 11-1. CONSUMERS OF LEAD FOR SOLDER IN 1987*
Facility/location
Los Angeles Water and Power Company, Los Angeles, CA
National Can Corp., Chicago, IL
Peerless Alloy Company, Denver, CO
Gardiner Metal Company, Chicago, ILa
Kester Solder Company, Chicago, IL
Ames Metal Product Company, Chicago, IL
Tara Corp., Granite City, ILb
Chicago CY Water and Sewer, Chicago, IL
Division Lead Company, Summit, IL
Johnson Manufacturing Company, Princeton, IA
Somerville Smelting Company, Somerville, MA
Detroit Metro Water Service, Detroit, MI
Kester Solder Company, Newark, NJ
Alpha Metals, Inc., Jersey City, NJ
Canfield MC Sons Company, Newark, NJ
Belmont Smelting and Ref. Works, Brooklyn, NY
Ney Smelting and Ref. Company, Inc, Brooklyn, NYb
Rochester Lead Works, Rochester, NY
New York Solder Company, Inc., Bronx, NY
Willard Lead Products Company, Charlotte, NCb
Avril GA Lead Products, Cincinnati, OH
GM Corp.-Packard Electric, Warner, OH
Oatey L R Company, Cleveland, OH
Victory White Metal Company, Cleveland, OHb
Rockwell International Corp., Dubois, IA
Acme Alloys, Philadelphia, PA
Pittsburgh Smelting and Ref. Company, Pittsburgh, PA
Crown Cork and Seal Company, Spartanburg, SC
Gen Dynamics, Ft. Worth, TX
Lead^Products^ Inc., Houston, TX
Multicore Solders, Inc., Richardson, TX
Murmur Corp., Dallas, TX
American National Can Company, Chicago, IL
Canaco Corp., Burbank, CA
Contl^ Can CG^ Inc., Norwalk CT
Reference 1.
^Facilities indicated accounted for 76 percent of total
consumption of lead for solder.
11-3
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may be ladled to molds for casting into bulk solder. However,
some facilities pipe the molten material directly to an extruder.
Bulk solder, in the form of bars and.ingots, is produced in
several ways. Most bulk solder is manufactured by simply casting
the alloy in a mold or by casting followed by extrusion. Some
manufacturers use rolling mills and stamping, which make solder
"preforms." Rolling and stamping are cold processes.
Wire solder is produced by extruding the alloy through
one-half inch diameter (or other small diameter) holes. The
molten solder may be transferred directly from the melting kettle
to the extruder or first may be cast into billets approximately
30 to 40 centimeters (12 to 16 in.) in length. The billets then
are pressed and extruded. Flux, which consists of a mixture of
melted rosin and activators, may be added to the solder at the
extruder. Following extrusion, the wire may be spooled or drawn
down to smaller sizes and then spooled prior to packing and
shipping. In general, extruding, drawing, and spooling also are
cold processes.
Drosses and slag produced during the manufacture of solder
may be recycled into the process or sold to other facilities for
refining and extraction.
11.1.1.2 Paste Solder Production. To produce paste solder,
an alloy first is formed by melting various amounts of tin and
lead in a melting kettle. The alloy then is converted into
powder form by spraying or centrifuging in an enclosed tank or
vessel. This process is similar to the process of producing lead
oxide for lead acid batteries (Section 6.1.5) or lead-based
pigments (Section 13.1.1). However, unlike lead oxide
production, oxygen is not introduced to the process. At least
one facility produces solder alloy powder in an atmosphere of
nitrogen. Following powder production, resins are added and
mixed with the powder in a closed container to produce a paste.
Waste generated from solder powder production can be recycled in
melting kettles.
11-4
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11.1.2 Ammunition Manufacturing7-8
To manufacture ammunition, lead alloy is put into a
gas-heated pot or'melting kettles that are operated at a
temperature of approximately 205°C (400°F). The base melting
kettle is perforated with a series of holes smaller than the shot
desired. The pot bottom is covered with a sludge of oxidized
lead so molten metal will ooze slowly through and form round
drops. During stirring of the pasty metal, spheres of molten
alloy flow through the sieve, break into individual drops, and
fall to the bottom of the shaft (mining shaft or tower) where
they are caught in a tank of water, which cools and solidifies
the shot into spherical shot. The shot then may be polished and
dried. Shot tumblers also may be used to further shape the shot.
The dross from the melting kettles is cooled and sold as scrap.
In bullet core manufacture, the lead is extruded as wire and
cut to length then swaged to the approximate shape of the bullet.
11.2 FUGITIVE EMISSION SOURCES4-5-7-8
General descriptions of fugitive dust sources and process
fugitive sources are provided in Sections 2.1 and 2.2,
respectively. Fugitive dust and process fugitive sources
specific to lead-based solder and ammunition manufacturing are
discussed in Sections 11.2.1 and 11.2.2, respectively. Little
information on fugitive emission sources was obtained on solder
and ammunition manufacturing facilities in the course of this
study. The following sections describe the most likely sources
of fugitive emissions based on information available.
11.2.1 Fugitive Dust
As described in Section 2.1, fugitive dust sources include
paved roads, unpaved roads, and storage piles. At most solder
and ammunition manufacturing facilities, the primary fugitive
dust sources are likely to be paved and unpaved roads.
The paved roads most likely to have the highest levels of
fugitive lead emissions are the haul roads to the plant and roads
used to transport virgin lead and scrap materials from storage
areas to the melting units. In addition, traffic areas in the
11-5
-------
vicinity of lead powder production units are likely to have high
fugitive lead emissions.
Lead fugitive dust may be emitted from the handling and
storage of feed materials and from wind erosion of open areas
around the plant. However, the fugitive lead emissions from
these sources are likely to be negligible.
11.2.2 Process Fugitives
Information on prpcess fugitive emissions from solder and
ammunition manufacturing is limited. Descriptions of the general
types of process fugitive emission sources can be found in
Section 2.2. The process fugitive lead emission sources at
solder manufacturing plants generally are associated with the
melting kettles and the powder production units used to
manufacture paste solder. The primary fugitive lead emission
sources associated with ammunition manufacturing are likely to be
the melting pot/shot tower and shot polishers and tumblers.
The primary source of lead emissions from solder and
ammunition manufacturing is the melting kettle. Emissions from
melting kettles generally are captured and ducted to a baghouse,
ESP, or are released to the atmosphere uncontrolled. Lead
emissions are typically in the form of PM, because the melting
kettle temperatures are usually not hot enough to cause the lead
to volatilize.
The paste solder production process is another potential
source of lead emissions. The spraying and centrifuging
operations typically are housed in enclosed tanks or vessels,
which limit the potential for lead emissions. However, when the
lead powder is added to the resin, there is some potential for
handling and spilling. Fabric filters, ESP's, and wet scrubbers
are used at some facilities to control emissions from this
process.
Lead emissions from rolling mills, extrusion, and stamping
operations are negligible because these operations are performed
after the processed alloy has cooled and is in solid form.
11-6
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11.3 ESTIMATING FUGITIVE EMISSIONS
The following sections discuss procedures for estimating
fugitive lead emissions from various lead-based solder and
ammunition manufacturing sources. Section 11.3.1 addresses
estimating lead emissions from fugitive dust sources, and
Section 11.3.2 addresses estimating process fugitive lead
emissions.
11.3.1 Fugitive dust
Lead emissions from paved and unpaved roads and storage
piles can be estimated using the equations provided in
Section 2.1. Because of variations from plant to plant in the
parameters used in these equations, site-specific data should be
used whenever possible to estimate fugitive dust emissions.
Section 2.1 also provides guidelines for obtaining the data
needed for the input parameters for these equations. Sampling
and analytical procedures for .road dust and storage pile samples
are provided in Appendices A and B, and analytical methods for
analyzing road and storage pile material samples for lead are
listed in Table 2-3. If plant-specific data are unavailable,
default values for many of the fugitive dust equation parameters
can be taken from the data presented in this report. However,
estimates derived using the default values presented in this
document should be used for preliminary assessment only.
To estimate lead fugitive dust emissions from paved roads
(Equation 2-2), average silt loading, the lead content of the
road dust silt fraction, average vehicle weights, and traffic
volume are required. Tables 2-1, 4-3, 5-4, 5-5, 9-5, and 9-6
include data on silt loadings of paved roads for a number of
industrial facilities. In the absence of plant specific data,
the information in these tables can be used to estimate silt
loadings. Data on the lead content of road silt were not
available for solder and ammunition manufacturing facilities.
However, the lead content in Table 5-4 for secondary lead
smelters could be used to estimate an upper limit to road silt
lead content. Appendix C provides information on weights of
11-7
-------
several industrial vehicles, and Section 2.1.1 describes methods
for estimating traffic volume.
Lead fugitive dust emissions from unpaved roads can be
estimated using Equation 2-4. The input parameters for the
equation include the silt content of the road surface material;
the lead content of the silt; average vehicle speed, weight, and
number of wheels; precipitation frequency; and traffic volume.
No data were available on solder manufacturing plant road dust.
However, Tables 2-5, 4-3, and 9-7 include data on the unpaved
road silt content for a number facilities. In the absence of
other data, the silt lead content presented in Table 5-4 can be
used to provide an upper limit to the lead content of unpaved
road silt. Table 5-6 and Appendix C include data that can be
used to estimated vehicle weight, speed, and number of wheels.
Figure 2-1 can be used to estimate the rainfall frequency, and
traffic volume can be estimated using procedures described in
Section 2.1.1.
Equations 2-6 and 2-8 can be used to estimate lead fugitive
dust emissions from storage piles. To estimate emissions related
to storage pile handling and transfer (Equation 2-6), mean wind
speed, material moisture content, and the lead content of the
silt fraction of the storage pile material are required. Mean
wind speeds are readily available from local meteorological
stations, and Appendix D includes data for several cities in the
United States. No data on storage pile material moisture and
lead content were located in the course of this study. The lead
content of storage pile material silt can be estimated from the
type of material stored. Because solder and ammunition
manufacturing facilities use virgin lead or scrap materials that
have very high lead contents, the lead content of storage pile
silt also can be expected to have a very high lead content. To
estimate wind erosion of active storage piles (Equation 2-8),
data are needed on silt content, lead content of the silt
fraction of the storage pile material, rainfall frequency, and
percentage of time that wind speed exceeds 5.4 m/sec (12 mph).
Data on wind speed and rainfall frequency can be obtained from
11-8
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local meteorological stations. Alternatively, Appendix D and
Figure 2-1 can be used to estimate these parameters.
11.3.2 Process Fugitives
The primary sources of process fugitive lead emissions from
solder manufacturing facilities are the melting kettles and
spraying, centrifuging, and lead powder transfer associated with
paste solder production. 'Emission factors for PM and lead
emissions from solder manufacturing sources are summarized in
Table 11-2. In general, the emission factors presented in the
table are based oh limited test and process data. Some tests
consisted of a single run, and some emission factors are based on
maximum production rates rather than on production rates measured
during the tests. Therefore, the emission factors presented in
Table 11-2 should be used with caution. Table 11-2 includes an
emission factor for fugitive emissions from the entire
melting/casting process. However, because of the questionable
quality of the data on which the process fugitive emission factor
is based, a more representative estimate of process fugitive
emission rates may be obtained by assuming the process fugitive
emission rates are a percentage of the stack emission rates.
No information was obtained on fugitive lead emission rates
for ammunition manufacturing facilities. However, because of
similarities in the processes, the emission factors presented in
Table 11-2 for solder melting kettle charging, melting, tapping,
and pouring should provide order-of-magnitude estimates of
process and fugitive lead emissions from ammunition
manufacturing.
11.4 CONTROLLING FUGITIVE EMISSIONS4'5'7'8
General descriptions of fugitive dust and process fugitive
emission controls are provided in Sections 3.1 and 3 ..2,
respectively. Little information on measures used to control
fugitive dust and process fugitive emissions at solder and
ammunition manufacturing plants was obtained in the course of
this study. The information that was obtained is summarized in
the following paragraphs.
11-9
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TABLE 1X-2,
SUMMARY OF EMISSION FACTORS FOR
MANUFACTURING
SOLDER
Source
Pollutant
Control device
No. of
tests
Emission factor
kg/Mg
Cast/extruded solder-virgin material-process emissions
Charging & melting
Refining
Tapping & pouring
Entire process
Entire process
Charging & melting
Refining
Tapping & pouring
Entire process
Charging & melting
Refining
Tapping & pouring
Entire process
Entire process
Charging & melting
Refining
Tapping & pouring
Entire process
Filt. PM
Fill. PM
Filt. PM
Filt. PM
Filt. PM
Filt. PM
Filt. PM
Fitt. PM
Filt. PM
Lead
Lead
Lead
Lead
Lead
Lead
Lead
Lead
Lead
None
None
None
None
Baghouse
ESP
ESP
ESP
ESP
None
None
None
None
Baghouse
ESP
ESP
ESP
ESP
1
1
1
1
2
1
i
1
1
1
1
1
1
2
1
1
1
1
0.40
0.22
0.17
0.78
0.038
0.0090
0.011
0.0090
0.029
0.0010
0.0012
0.0012
0.0033
0.0016
3.7xlO-5
2.4xia5
l.SxlO"5
0.00008
Ib/ton
0.80
0.43
0.33
1.6
0.077
0.018
0.022
0.018
0.058
0.0020
0.0023
0.0023
0.0066
0.0032
7.4X10"5
0.000047
0.000035
0.00016
Ref.
5
5
5
5
4
5
5
5
5
5
5
5
5
4
5
5
5
5
Cast/extruded solder— virgin material— process fugitives
Entire processa
Entire processa'b
Filt. PM
Lead
*
0.065
0.0044
0.13
0.0087
5
5
Cast/extruded solder— recycle material— 60% lead/40% tin— process emissions
Charging & melting
Defining
Tapping & pouring
Entire process
Filt. PM
Filt. PM
Filt. PM
Filt. PM
ESP
ESP
ESP
ESP
1
1
1
1
0.070
0.026
0.026
0.12
0.14
0.052
0.052
0.24
4
4
4
4
>aste solder— process emissions
'owder production unit
'owder production unit
'owder production unit
'owder production unit
Filt. PM
Filt. PM
Lead
Lead
None
Wet scrubber
None
Wet scrubber
1
1
1
1
49
0.41
1.7
0.012
97
0.81
3.3
0.024
5
5
5
5
Filt. PM = filterable PM as measured using EPA Method 5.
aBased on vacuum station catch with estimated 50 percent
capture efficiency.
bBased on lead:PM ratio of 0.067.
11-10
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The available information indicates that paved roads at some
solder and ammunition manufacturing facilities are swept with
industrial sweepers or watered at regular intervals to control
fugitive dust emissions. Unpaved areas are sprayed with a
chemical dust suppressant for fugitive dust control. The control
measures described in Section 3.1 generally should be applicable
to solder manufacturing facilities.
The available information indicates that some melting
kettles or pot furnaces are hooded and vented to control devices
to control fugitives from these sources. Other applicable
control measures are described in Section 3.2 of this report.
11.5 REFERENCES FOR CHAPTER 11
1. Technical Memorandum, C. Hester, Midwest Research Institute
to Deborah Michelitsch, U. S. Environmental Protection
Agency, Research Triangle Park, North Carolina, Assessment of
Lead Emissions from the Manufacture of Solder, May 5, 1989.
2. Hester, C., Assessment of Lead Emissions from the Manufacture
of Solder, Interim Report—March 31, 1989, prepared for
Deborah Michelitsch, U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina.
3. Neil V. Maresca, Small Businessmanfs Guide to the OSHA Lead
Standard, International Lead Zinc Research Organization Inc.,
New York, July 30, 1983.
4. Written Communication, M. Allen, Illinois Environmental
Protection Agency, to R. Marinshaw, Midwest Research
Institute, Information on Lead Processes and Emissions for
Taracorp Industries, Incorporated, Granite City, Illinois,
December 10, 1993.
5. Written Communication, M. Allen, Illinois Environmental
Protection Agency, to R. Marinshaw, Midwest Research
Institute, Information on Lead Processes and Emissions for
Kester Solder, Des Plaines, Illinois, December 15, 1993.
6. Mineral Industry Surveys—Lead in June 1993, Bureau of Mines,
U. S. Department of the Interior, Washington, D.C.,
September 23, 1993.
7. Hester, C., Assessment of Lead Emissions from the Manufacture
of Solder, Interim Report—March 31, 1989, prepared for
Deborah Michelitsch, U. S. Environmental Protection Agency,
Research Triangle -Park, North Carolina.
11-11
-------
8. Written Communication, M. Martin, Illinois Environmental
Protection Agency, to R. Marinshaw, Midwest Research
Institute, Information on Lead Processes and Emissions for
Olin Corporation, East Alton, Illinois, December 17, 1993.
11-12
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12.0 LEAD-BASED INORGANIC PIGMENT MANUFACTURING
12.1 PROCESS DESCRIPTION1
The major lead-based inorganic pigment is "red lead" (Pb3O4),
which is used principally in ferrous metal protective paints.
Other lead-based inorganic pigments include white lead and lead
chromates. There are several commercial varieties of white lead
including leaded zinc oxide, basic carbonate white lead, basic
sulfate white lead, and basic lead silicates.
The manufacturing of lead-based inorganic pigments begins
with the production of lead oxide. Lead oxide is a general term
and can mean either lead monoxide or "litharge" (PbO); lead
tetroxide or red lead; or "black" or "gray" oxide, which is a
mixture of 70 percent lead monoxide and 30 percent metallic lead.
Litharge is used primarily in the manufacture of various ceramic
products. However, litharge also is used in a number of other
products, including white lead-based inorganic pigment.
Black lead is made for specific use in the manufacture of
lead-acid storage batteries. Because of the size of the lead-
acid battery industry, lead monoxide is the most important
commercial compound of lead, based on volume. Lead oxide
production for uses other than for storage batteries totalled
63,225 Mg (69,548 tons) in 1992.2 These other uses included the
production of paint, ceramics, glass, pigments and other
chemicals.
The various processes used to produce lead oxide and lead-
based inorganic pigments are described in Sections 12.1.1 and
12.1.2, respectively.
12-1
-------
12.1.1 Lead. Oxide Production
Commercial lead oxides all can be prepared by wet chemical
methods. However, with the exception of lead dioxide, lead oxides
generally are produced by thermal processes in which lead is
directly oxidized with air. These processes may be classified
according to the temperature of the reaction: (1) low
temperature, below the melting point of lead; (2) moderate
temperature, between the melting points of lead and lead
monoxide; and (3) high temperature, above the melting point of
lead monoxide.
12.1.1.1 Low Temperature Oxidation. Low temperature
oxidation of lead is accomplished by tumbling slugs of metallic
lead in a ball mill through which continuous air flow is
maintained. The air flow provides oxygen and is used as a
coolant. If the process were not cooled, the heat generated by
the oxidation of the lead plus the mechanical heat of the
tumbling charge would raise the charge temperature above the
melting point of lead. The ball mill product is a lead oxide
that is 20 to 50 percent free lead.
12.1.1.2 Moderate Temperature Oxidation. Three processes
are used commercially in the moderate temperature range:
(1) refractory furnace, (2) rotary tube furnace, and (3) the
Barton Pot process. The refractory furnace process uses a cast
steel pan equipped with a rotating vertical shaft and a
horizontal crossarm mounted with plows. The plows move the lead
charge continuously to expose fresh surfaces of metallic lead for
oxidation. The charge is heated by a gas flame on its surface.
Oxidation of the charge supplies much of the reactive heat as the
reaction progresses. A variety of products can be manufactured
from pig lead feed by varying the feed temperature and the time
in the furnace. Yellow litharge can be made in a refractory
furnace by heating the charge for several hours at 600°C to 700°C
(1112°F to 1292°F). However, the yellow litharge produced may
contain traces of red lead and/or free metallic lead.
In the rotary tube furnace process, molten lead is
introduced into the upper end of a refractory-lined inclined
12-2
-------
rotating tube. An oxidizing flame in the lower end maintains the
desired temperature of reaction. The tube is long enough so that
the charge is completely oxidized when it emerges from the lower
end. This type of furnace commonly has been used to produce lead
monoxide, but it is not unusual for the final product to contain
traces of both free metallic and red lead.
LEAD
FEED
LEAD OXIDE
AIR
LEAD
GAS STREAM
CONVEYER
(PRODUCT TO STORAGE)
Figure 12-1. Lead oxide Barton Pot process.1
The Barton Pot process, shown in Figure 12-1, uses a cast
iron pot with an upper and lower stirrer rotating at different
speeds. Molten lead is fed through a port in the cover into the
pot, where it is broken up into droplets by high-speed blades.
Heat is supplied initially to develop an operating temperature
from 370°C to 480°C (698°F to 896°F). The exothermic heat from
the resulting oxidation of the droplets is usually sufficient to
maintain the desired temperature. The oxidized product is swept
out of the pot by an air stream.
The operation is controlled by adjusting the rate of molten
lead feed, the speed of the stirring blades, the temperature of
the system, and the rate of air flow through the pot. The Barton
Pot can be used to produce litharge, black lead oxide, or gray
lead oxide.
12-3
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12.1.1.3 High Temperature Oxidation. High temperature
oxidation is a fume-type process. A very fine-grained, high-
purity litharge is made by burning a fine stream of molten lead
in a special blast-type burner, which maintains a flame
temperature of approximately 1200°C (2192°F). The fume is swept
out of the chamber by an air stream, cooled in a series of
"goosenecks," and collected in a baghouse. The median particle
diameter is from 0.50 to 1.0 /im, as compared with 3.0 to 16.0 /an
for lead monoxide manufactured by other methods.
12.1.2 Lead-Based Inorganic Pigment Production
Basic carbonate white lead production is based on the
reaction of litharge with acetic acid or acetate ions. This
product is then reacted with carbon dioxide to form lead
carbonate. White leads (other than carbonates) are made either
by chemical, fuming, or mechanical blending processes. Red lead
is produced by oxidizing litharge in a reverberatory furnace.
Lead chromate pigments have been prepared by a variety of
methods, most of which involve precipitation of the lead chromate
pigment from aqueous solutions of its constituent ions in amounts
that vary according to the shade of pigment desired. The
constituent ions may be lead, chromate, sulfate, or molybdate.
Conventionally, an aqueous solution containing the soluble
anionic salts is mixed with a lead salt in the form of an aqueous
slurry or an aqueous solution. After precipitation, but prior to
isolation, the lead chromate pigment is commonly treated with a
variety of hydrous oxides to provide a loose porous coating on
the surface of the pigment to enhance properties such as
lightfastness. Metal chromate pigments, manufactured in aqueous
systems, are commonly dried to a powder prior to shipment and use
in coating compositions.3
12.2 FUGITIVE EMISSION SOURCES
The primary fugitive dust emission sources at lead-based
inorganic pigment manufacturing facilities are paved and unpaved
roads; the primary process fugitive emission sources at these
facilities include charging and tapping refractory furnaces,
12-4
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reverberatory furnaces, rotary tube furnaces, and Barton Pots.
General descriptions of fugitive dust sources and process
fugitive sources are provided in Sections 2.1 and 2.2,
respectively. For the purposes of this study, little information
was available on fugitive emissions from lead-based inorganic
pigment manufacturing. Table 12-1 lists the fugitive dust
emission sources that characterize facilities that produce lead
oxide and lead-based inorganic pigments; the potential process
fugitive sources for lead oxide and lead-based inorganic pigment
manufacturing are listed in Table 12-2.
TABLE 12-1. FUGITIVE DUST EMISSION SOURCES FOR THE
PRODUCTION OF LEAD OXIDE AND PIGMENTSa
Fugitive Dust Sources
Material Transfer
Outdoor bulk loading stations
Outdoor bulk unloading stations
Spills as a result of feed material transfer
Railcar traffic
Vehicular traffic on paved and unpaved roads
Material Storage
Feed material storage
Dried metal chrotnate pigment packaging, pouring, and handling
aReference 4.
12.3 ESTIMATING FUGITIVE EMISSIONS
The following sections discuss procedures for estimating
fugitive lead emissions from various lead oxide and pigment
production sources. Section 12.3.1 addresses estimating lead
emissions from fugitive dust sources, and Section 12.3.2
addresses estimating process fugitive lead emissions.
12.3.1 Fugitive Dust
Lead emissions from paved and unpaved roads and storage
piles can be estimated using the equations provided in
Section 2.1. Because of variations from plant to plant in the
parameters used in these equations, site-specific data should be
used whenever possible to estimate fugitive dust emissions.
Section 2.1 also provides guidelines for obtaining the data
12-5
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TABLE 12-2. PROCESS FUGITIVE EMISSION SOURCES
FOR THE PRODUCTION OF LEAD OXIDE AND PIGMENTSa
Process Fugitive Sources
Chemical processes (production of non-carbonate white lead)
Fuming processes (production of non-carbonate white lead)
Mechanical blending processes (production of non-carbonate white lead)
Reverberatory furnace charging (production of red lead)
Reverberatory furnace tapping (production of red lead)
Reverberatory furnace leaking (production of red lead)
Thermal processes (production of lead oxides)
Ball mill (low-temperature oxidation of lead)
Refractory furnace feed (moderate temperature oxidation of lead)
Rotary tube furnace feed (moderate temperature oxidation of lead)
Barton pot process feed (moderate temperature oxidation of lead)
Lead oxide and lead fed to the settling chamber of the Barton process
Burner feed (high temperature oxidation of lead)
Furnace leakage
aReference 4.
needed for the input parameters for these equations. Sampling
and analytical procedures for road dust and storage pile samples
are provided in Appendices A and B, and analytical methods for
analyzing road and storage pile material samples for lead are
listed in Table 2-3. If plant-specific data are unavailable,
default values for many of the fugitive dust equation parameters
can be taken from the data presented in this report. However,
estimates derived using the default values presented in this
document should be used for preliminary assessment only.
To estimate lead fugitive dust emissions from paved roads
(Equation 2-2), average silt loading, the lead content of the
road dust silt fraction, average vehicle weights, and traffic
volume are required. Table 2-1 includes data on silt loadings of
paved roads for a number of industrial facilities. In addition,
Tables 4-3, 5-4, 5-5, 9-5, and 9-6 include data on silt loadings
at some of the industries addressed in this report. In the
absence of plant specific data, the information in these tables
can be used to estimate silt loadings. Data on the lead content
12-6
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of road silt were not available for lead-based inorganic pigment
manufacturing facilities. However, the lead content in Table 5-4
for secondary lead smelters could be used to estimate an upper
limit to road silt lead content. Appendix C provides information
on weights of several industrial vehicles, and Section 2.1.1
describes methods for estimating traffic volume.
Lead fugitive dust emissions from unpaved roads can be
estimated using Equation 2-4. The input parameters for the
equation include the silt content of the road surface material;
the lead content of the silt; average vehicle speed, weight, and
number of wheels; precipitation frequency; and traffic volume.
No data were available on lead-based inorganic pigment
manufacturing plant road dust. However, Table 2-5 includes data
on the unpaved road silt content for a number facilities. In
addition, Tables 4-3 and 9-7 include data on unpaved road silt
content at some of the industries addressed in this report. In
the absence of other data, the silt lead content presented in
these tables can be used to estimate the lead content of unpaved
road silt. Table 5-6 and Appendix C include data that can be
used to estimated vehicle weight, speed, and number of wheels.
Figure 2-1 can be used to estimate the rainfall frequency, and
traffic volume can be estimated using procedures described in
Section 2.1.1.
Equations 2-6 and 2-8 can be used to estimate lead fugitive
dust emissions from storage piles. To estimate emissions related
to storage pile handling and transfer (Equation 2-6), mean wind
speed, material moisture content, and the lead content of the
silt fraction of the storage pile material are required. Mean
wind speeds are readily available from local meteorological
stations, and Appendix D includes data for several cities in the
United States. No data on storage pile material moisture and
lead content for lead-based inorganic pigment manufacturing
facilities were located in the course of this study. The lead
content of storage pile material silt can be estimated from the
type of material stored. Because lead-based inorganic pigment
manufacturing facilities use virgin lead, the lead content of
12-7
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storage pile silt can be expected to have a very high lead
content. To estimate wind erosion of active storage piles
(Equation 2-8), data are needed on silt content, lead content of
the silt fraction of the storage pile material, rainfall
frequency, and percentage of time that wind speed exceeds
5.4 m/sec (12 mph). Data on wind speed and rainfall frequency
can be obtained from local meteorological stations.
Alternatively, Appendix D and Figure 2-1 can be used to estimate
these parameters.
12.3.2 Process Fugitives
Emission factors for lead emissions from process fugitive
sources for the lead-based inorganic pigment manufacturing were
not available. However, order of magnitude estimates of fugitive
lead emissions from furnaces can be made using emission factors
for lead emissions from process sources and estimates of the
capture efficiency of control devices used. Lead emission
factors for lead oxide and pigment production process sources are
given in Table 12-3.
TABLE 12-3.
EMISSION FACTORS FOR LEAD EMISSIONS FROM LEAD
OXIDE AND PIGMENT PRODUCTION3
Process
Lead emission factor
kg/Mg of product
Ib/ton of product
Lead oxide production
Barton pot*3
Calciner, uncontrolled
Calciner with baghouse
0.22
7.00
0.024
0.44
14.00
0.05
Pigment production
Red lead production,
entire process with
baghouseb
White lead production,
entire process with
baghouse"
Chrome pigments
0.50
0.28
0.065
0.90
0.55
0.13
aReference 1. Emission factors are for total lead emissions,
The percentage of fugitive lead emissions is not known.
^Baghouse is considered process equipment.
12-8
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12.4 FUGITIVE EMISSION CONTROLS
General descriptions of fugitive dust and process fugitive
emission controls are provided in Sections 3.1 and 3.2,
respectively. The following paragraphs describe some of the
measures used to control fugitive emissions at specific lead-
based inorganic pigment manufacturing facilities.
12.4.1 Fugitive Dust Emission Controls4"7
The following fugitive lead dust control methods are some of
the methods implemented by lead oxide and pigment manufacturing
facilities.
1. Outdoor storage of lead-containing powder material takes
place in closed containers. To prevent high concentrations of
lead dust escaping into the atmosphere, one State does not permit
facilities to create or maintain outdoor storage of bulk
materials if the fraction that is less than 0.075 mm (200 mesh)
contains more than 1.0 percent lead by weight.
2. For trailer loading operations, the connection between
the loading spout and .the trailer hatch must be air-tight. The
loading spout is designed to provide a smooth uninterrupted
material flow path to prevent escape of fugitive emissions. The
loading operation and associated conveyers are totally enclosed
and vented through a baghouse. Fabric collectors are also
installed to draft the bulk loading system and trailer. The bulk
loading system is purged to clear the residual material into the
loaded trailer. The spout is vibrated to dislodge any left over
material, and the trailer hatch is closed. The loading spout and
hatch are vacuumed to capture any remaining material.
3. Building floors and equipment are cleaned on a daily
basis in the loading area.
4. For litharge bulk truck unloading, a pulsaire filter is
activated while the litharge is being unloaded.
5. If an outdoor spill occurs, a vacuum cleaning device is
used to clean up the spill to minimize lead fugitive emissions to
the atmosphere.
12-9
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6. Drums of product are wet-wiped after packing is
complete.
7. HEPA filters are installed on all stacks.
8. All outdoor paved surfaces are maintained to minimize
accumulation of lead dust.
9. The trailer parking lot is chipped and sealed every
spring and swept on a regular basis.
10. All access roads to the public highway are paved.
An operation and maintenance plan, can also reduce the risk
of fugitive lead emissions caused by malfunctions of process or
control equipment. "Good housekeeping" is essential to limiting
the escape of fugitive lead emissions.
12.4.2 Process Fugitive Emission Controls'
Collection of dust and.fumes from the production of lead
pigments is an economic necessity, because PM emissions, although
small, are as much as 90 percent lead. For that reason, process
operations generally are well controlled. Automatic shaker-type
fabric filters, often preceded by cyclone mechanical collectors
or settling chambers, are the common control devices for
collecting lead oxides and pigments. Control efficiencies of
99 percent are achieved with these control device combinations.
Where fabric filters are not appropriate scrubbers may be used to
achieve control efficiencies from 70 to 95 percent. Lead
recovered from PM control devices is recycled in ball mill and
Barton Pot processes of black oxide manufacturing. Emissions
data from the production of white lead pigments are not
available. The emissions from dryer exhaust scrubbers account
for over 50 percent of the total lead emitted in lead chrornate
production.
12.5 REFERENCES FOR CHAPTER 12
1. Compilation of Air Pollutant Emission Factors, Volume I:
Stationary Point and Area Sources, AP-42, U. S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
September 1993.
2. Mineral Industry Surveys—Lead in June 1993, Bureau of Mines,
U. S. Department of the Interior, Washington, D.C.,
September 23, 1993.
12-10
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3. Inorganic Pigments, Manufacturing Processes, Edited by M. H.
Gutcho, Noyes Data Corporation, 1980, pp. 70-99.
4. Written Communication, S. Patel, Hammond Lead Products,
Hammond, Indiana, to J. Ziga, Hammond Department of
Environmental Management, Hammond, Indiana, Revised fugitive
dust program, August 29, 1991.
5. Written Communication, T. Method, Indiana Department of
Environmental Management, to R. Turner, Oxide & Chemical
Corporation, Amendment to operation permit No. 11-03-89-0046
for Oxide & Chemical Corporation, August 4, 1989.
6. Written Communication, T. Method, Indiana Department of
Environmental Management, to R. Turner, Oxide & Chemical
Corporation, Amendment to operation permit No. 11-03-89-0046
for Oxide & Chemical Corporation, September 26, 1989.
7. Written Communication, R. Lindsay, U. S. Environmental
Protection Agency, Region 5, Chicago, Illinois, to R.
Marinshaw, Midwest Research Institute, Information on Indiana
lead rules and fugitive dust control measures, September 17,
1993.
12-11
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13.0 PRESSED AND BLOWN GLASS MANUFACTURING
13.1 PROCESS DESCRIPTION1
Commercially produced glass can be classified as soda-lime,
lead, fused silica, borosilicate, or 96 percent silica.
Soda-lime glass, since it constitutes 77 percent of total glass
production, is discussed here. Soda-lime glass consists of sand,
limestone, soda ash, and cullet (broken glass). Soda-lime glass
manufacturing consists of the following four phases:
(1) preparing the raw material, (2) melting in a furnace,
(3) forming and (4) finishing. Figure 13-1 is a diagram for
typical glass manufacturing.
The products of this industry are flat glass, container
glass and pressed and blown glass. The procedures for
manufacturing glass, except forming and finishing, are the same
for all products. Container glass and pressed and blown glass,
51 and 25 percent, respectively, of total soda-lime glass
production use pressing, blowing, or pressing and blowing to form
the desired product. Flat glass, 24 percent of soda-lime glass
production, is formed by float, drawing or rolling processes.
13.1.1 Raw Materials
The sand, limestone and soda ash raw materials are received,
crushed and stored in separate elevated bins. These materials
are then transferred through a gravity feed system to a weigher
and mixer, where the material is mixed with cullet to ensure
homogeneous melting. The mixture is conveyed to a batch storage
bin and held until dropped into the feeder to the melting
furnace. All equipment used in handling and preparing the raw
material is housed separately from the furnace and is usually
13-1
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RAW MATERIAL
HANDLING
SCC: 3-05-014-10
i
MELTING
SCC: 3-05-014-02, 03,04
A A
A A
GLASS FORMING
SCC: 3-05-014-06, 07, 08
GULLET CRUSHING
SCC: 3-05-014-13
Recycle
Undesirable
Glass
ANNEALING
I
INSPECTION
AND TESTING
I
PACKING
FINISHING
SCC: 3-05-014-06,07,08
FINISHING
SCC: 3-05-014-06,07,08
KEY
Q PM emissions
(2) Gaseous emissions
STORAGE OR
SHIPPING
Figure 13-1. Process flow diagram for the glass manufacturing.
13-2
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referred to as the batch plant. Figure 13-2 is a flow diagram of
a typical batch plant.
13.1.2 Furnace
The furnace most commonly used is a continuous regenerative
furnace capable of producing between 45 and 272 megagrams (Mg)
(50 and 300 tons) of glass per day. A furnace may have either
side or end ports that connect brick checkers to the inside of
the melter. The purpose of brick checkers (Figures 13-3 and
13-4) is to conserve fuel by collecting furnace exhaust gas heat
which, when the air flow is reversed, is used to preheat the
furnace combustion air. As material enters the melting furnace
through the feeder, it floats on the top of the molten glass
already in the furnace. As it melts, it passes to the front of
the melter and eventually flows through a throat leading to the
refiner. In the refiner, the molten glass is heat-conditioned
for delivery to the forming process. Figures 3 and 4 show side-
port and end-port regenerative furnaces.
13.1.3 Material Shaping
After refining, the molten glass leaves the furnace through
forehearths (except in the float process, in which molten glass
moves directly to the tin bath) and goes to be shaped by
pressing, blowing, pressing and blowing, drawing, rolling or
floating to produce the desired product. Pressing and blowing
are performed mechanically, using blank molds and glass cut into
sections (gobs) with a set of shears. In the drawing process,
molten glass is drawn upward in a sheet through rollers, with the
thickness of the sheet determined by the speed of the draw and
the configuration of the draw bar. The rolling process is
similar to the drawing process except that the glass is drawn
horizontally on plain or patterned rollers and, for plate glass,
requires grinding and polishing. The float process is different
from the drawing process, having a molten tin bath over which the
glass is drawn and formed into a finely finished surface
requiring no grinding or polishing. The end product undergoes
finishing (decorating or coating) and annealing (removing
unwanted stress areas in the glass) as required and is then
13-3
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GULLET
RAW MATERIALS
RECEIVING HOPPER
//nn\\
FILTER
VENTS
TO ATM
STORAGE BINS MAJOR
RAW MATERIALS
BELT CONVEYOR
BATCH
STORAGE
BIN
GLASS
MELTING
FURNACE
Figure 13-2. General diagram of a batch plant.
13-4
-------
GLASS SURFACE IN REFINER
WELTER SIDE WALL
REFINER SIDE WALL
THROAT
GLASS SURFACE IN MELTER
ATURAL DRAFT STACK
BACK WALL
'EEOEH
COMBUSTION AIR BLOWER BLOWER
MOVABLE REFRACTORY BAFFLE
RIDER ARCHES
HARD WALL
Figure 13-3. Side port continuous regenerative furnace,
13-5
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GLASS SURFACE IN
MELTEH REFINER SIDE WALL
INDUCED DRAFT FAN
PARTING WALL'
FOREH EARTH
BACK WALL
PRIMARY CHECKERS .
CURTAIN WALL
SECONDARY CHECKERS
RIDER ARCHES
Figure 13-4. End port continuous regenerative furnace.
13-6
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inspected and prepared for shipment to market. Any damaged or
undesirable glass is transferred back to the batch plant to be
used as cullet.
13.2 EMISSIONS AND CONTROLS1
Fugitive dust can be controlled with 99 to 100 percent
efficiency by enclosing all possible dust sources and using
baghouses or cloth filters. Another way to control dust
emissions, also with an efficiency approaching 100 percent, is to
treat the batch to reduce the amount of fine particles present by
presintering, briquetting, pelletizing, or liquid alkali
treatment.
The melting furnace contributes over 99 percent of the total
emissions from a glass plant, both PM and gaseous pollutants.
Particulate matter results from volatilization of materials in
the melt that combine with gases and form condensates. These
either are collected in the checker work and gas passages or are
emitted to the atmosphere. Serious problems arise when the
checkers are not properly cleaned, in that slag can form, clog
the passages, and eventually deteriorate the condition and
efficiency of the furnace. Proper maintenance and firing of the
furnace can control emissions, add to the efficiency of the
furnace, and reduce operational costs. Low-pressure wet
centrifugal scrubbers have been used to control PM, but their
inefficiency (approximately 50 percent) indicates their inability
to collect particulate matter of submicron size. High-energy
venturi scrubbers are approximately 95 percent effective in
reducing PM emissions. Baghouses, with up to 99 percent PM
collection efficiency, have been used on small regenerative
furnaces, but fabric corrosion requires careful temperature
control. Electrostatic precipitators have an efficiency of up to
99 percent in collecting particulate matter.
Emissions from the forming and finishing phase depend upon
the type of glass being manufactured. For container, press, and
blow machines, the majority of emissions results from the gob's
coming into contact with the machine lubricant. Emissions, in
13-7
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the form of a dense white cloud that can exceed 40 percent
opacity, are generated by flash vaporization of hydrocarbon
greases and oils. Grease and oil lubricants are being replaced
by silicone emulsions and water-soluble oils, which may virtually
eliminate this smoke. For flat glass, the only contributor to
air pollutant emissions is gas combustion in the annealing lehr
(oven), which is totally enclosed except for product entry and
exit openings. Because emissions are small and operational
procedures are efficient, no controls are used on flat glass
processes.
No data are available of the magnitude of fugitive emissions
from the manufacture of leaded glass. However, AP-42 includes an
emission factor for lead emissions from the overall leaded glass
process of 2.5 kg/Mg (5 Ib/ton) and indicates that the PM
emissions contain 23 percent lead by weight.
13.3 REFERENCES
1. Supplement E 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.
S eptember 1990.
13-8
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APPENDIX A
PROCEDURES FOR SAMPLING SURFACE AND BULK MATERIALS
This appendix presents procedures recommended for the
collection of material samples from paved and unpaved roads and
from storage piles. Appendix B presents analogous information
for the analyses of the samples. These recommended procedures
are based on a review of American Society for Testing and
Materials (ASTM) methods such as C-136 (sieve analysis) and
D-2216 (moisture content). The recommendations follow ASTM
standards where practical, and where not, an effort was made to
develop procedures consistent with the intent of the pertinent
ASTM standards.
The following emphasizes that, prior to the start of any
field sampling program, one must first define the study area of
interest and determine the number of samples that can be
collected and analyzed within the constraints of time, labor and
money available. For example, the study area could be defined as
an individual industrial plant with its network of paved/unpaved
roadways and material piles. In that instance, it is
advantageous to collect a separate sample for each major dust
source in the plant. This level of resolution is useful in
developing cost-effective emission reduction plans. On the other
hand, the area of interest may be geographically large (say, for
example, a city or county with its network of public roads) so
that collection of at least one sample from each source would be
highly impractical. For example, one may be interested in
inventorying emissions from public paved and unpaved roads in one
county of a western state. In that case, it would be important
to obtain .samples that are representative of different source
types within the area.
A-l
-------
Left blank for production
A-2
-------
SECTION A.l
SAMPLES FROM UNPAVED ROADSOBJECTIVE
OBJECTIVE
The overall objective in an unpaved road sampling program is
to inventory the mass of particulate matter (PM) emissions from
the roads. This is typically done by
1. Collecting "representative" samples of the loose
surface material from the road,
2. Analyzing the samples to determine silt fractions, and,
3. Using the results in the predictive emission factor
model given in AP-42 Section 11.2.1 together with
traffic data (e.g., number of vehicles traveling the
road each day).
Prior to any field sampling program, it is necessary to
define the study area of interest and to determine the number of
unpaved road samples that can be collected and analyzed within
the constraints of time, labor and money available. For example,
the study area could be defined as a very specific industrial
plant in which there is a network of roadways. In that instance,
it is advantageous to collect a separate sample for each major
unpaved road in the plant. This level of resolution is useful in
developing cost-effective emission reduction plans involving dust
suppressants or traffic rerouting. On the other hand, the area
of- interest may be geographically large, and well-defined traffic
information may not be easily obtained. In that case., resolution
of the PM emission inventory to specific road segments would not
be feasible, and it would be more important to obtain samples
that are representative of road types within the area by
aggregating several sample increments.
A-3
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PROCEDURE
For a network consisting of many relatively short roads
contained in a well-defined study area (as would be the case at
an industrial plant), it is recommended that one collect a sample
for each 0.8 km (0.5 mi) length, or portion thereof, for each
major road segment. Here, the term "road segment" refers to the
length of road between intersections (the nodes of the network)
with other paved or unpaved roads. Thus, for a major segment
1 km (0.6 mi) long, two samples are recommended.
For longer roads in study areas that are spatially diverse.
it is recommended that one collect a sample for each 4.8 km
(3 mi) length of the road. Composite the sample from a minimum
of three incremental samples. Collect the first sample increment
at a random location within the first 0.8 km (0.5 mi), with
additional increments taken from each remaining 0.8 km (0.5 mi)
of the road up to a maximum length of 4.8 km (3 mi). For a road
less than 1.5 mi in length, an acceptable method for selecting
sites for the increments is based on drawing three random numbers
(xl, x2, x3) between zero and the length. Random numbers may be
obtained from tabulations in statistical reference books, or
scientific calculators may be used to generate pseudorandom
numbers. See Figure A-l.
The following steps describe the collection method for
samples (increments).
1. Ensure that the site offers an unobstructed view of
traffic and that sampling personnel are visible to
drivers. If the road is heavily traveled, use one
person to "spot" and route traffic safely around
another person collecting the surface sample
(increment).
2. Using string or other suitable markers, mark a 0.3 m
(1 ,ft) width across the road. (WARNING: Do not mark
the collection area with a chalk line or in any other
method likely to introduce fine material into the
sample.)
A-4
-------
Ul
L = 4.8km (3 Mi.)
W = 9.1m (30 ft.)
Sample Strip
20cm (8 in.) Wide
L = 1.6km (1 Mi.)
Figure A-l. Sampling locations for unpaved roads.
-------
3. With a whisk broom and dustpan, remove the loose
surface material from the hard road base. Do not
abrade the base during sweeping. Sweeping should be
performed slowly so that fine surface material is not
injected into the air. NOTE: Collect material only
from the portion of the road over which the wheels and
carriages routinely travel (i.e., not from berms or any
"mounds" along the road centerline).
4. Periodically deposit the swept material into a clean,
labeled container of suitable size (such as a metal or
plastic 19 L [5 gal] bucket) with a scalable
polyethylene liner. Increments may be mixed within
this container.
5. Record the required information on the sample
collection sheet (Figure A-2).
SAMPLE SPECIFICATIONS
For uncontrolled unpaved road surfaces, a gross sample of
5 kg (10 Ib) to 23 kg (50 Ib) is desired. Samples of this size
will require splitting to a size amenable for analysis (see
Appendix B). For unpaved roads that have been treated with
chemical dust suppressants (such as petroleum resins, asphalt
emulsions, etc.), the above goal may not be practical in well-
defined study areas because a very large area would need to be
swept. In general, a minimum of 400 g (1 Ib) is required for
silt and moisture analysis. Additional increments should be
taken from heavily controlled unpaved surfaces, until the minimum
sample mass has been achieved.
A-6
-------
Date Collected
SAMPLING DATA FOR UNPAVED ROADS
. Recorded by
Road Material (e.g., gravel, slag, dirt, etc:):1
Site of sampling:
METHOD:
1. Sampling device: whisk broom and dustpan
2. Sampling depth: loose surface material (do not abrade road base)
3. Sample container: bucket with scalable liner
4. Gross sample specifications:
a. Uncontrolled surfaces - 5 kg (10 Ib) to 23 kg (50 Ib)
b. Controlled surfaces — minimum of 400 g (1 Ib) is required for analysis
Refer to procedure described in Section 1.0 of "Appendix D to AP-42" for more detailed
instructions.
Indicate any deviations from the above
SAMPLING DATA COLLECTED:
Sample
No.
Time
Location +
Surf.
Area
Depth
Mass of
Sample
'Indicate and give details if roads are controlled.
+ Use code given on plant or road map for segment identification. Indicate sampling location
on map.
Figure A-2. Example data form for unpaved road samples,
A-7
-------
left blank for production
A-8
-------
SECTION A.2
SAMPLES FROM PAVED ROADS
OBJECTIVE ' '
The overall objective in a paved road sampling program is to
inventory the mass of particulate emissions from the roads. This
is typically done by
1. Collecting "representative" samples of the loose
surface material from the road,
2. Analyzing the sample to determine the silt fraction,
and,
3. Combining the results with traffic data in a predictive
emission factor model.
The remarks made earlier about definition of the study area
and the appropriate level of resolution are equally applicable to
paved roads. Prior to the field sampling program, it is
necessary to first define the study area of interest and to then
determine the number of paved road samples that can be collected
and analyzed. For example, it is advantageous to collect a
separate sample for each major paved road in a well-defined study
area (e.g., an industrial plant) because the resolution can be
useful in developing cost-effective emission reduction plans.
Similarly, in geographically large study areas, it may be more
important to obtain samples that are representative of road types
within the area by aggregating several sample increments.
In comparison to unpaved road sampling, planning for a paved
road sample collection exercise necessarily involves greater
consideration as to types of equipment to be used. Specifically,
provisions must be made to accommodate the characteristics of
the vacuum cleaner chosen. For example, paved road samples are
collected by cleaning the surface with a vacuum cleaner using
"tared" (i.e., weighed before use) filter bags. "Stick broom"
vacuums use relatively small, lightweight filter bags, while bags
A-9
-------
for "industrial-type" vacuums are bulky and heavy. Stick brooms
are thus well suited for collecting samples from lightly loaded
road surfaces because the mass collected is usually several times
greater than the bag tare weight. On the other hand, the larger
industrial-type vacuum bags are easier to use on heavily loaded
roads and can be more readily used to aggregate incremental
samples from all road surfaces. These features are discussed in
greater detail in the Appendix.
PROCEDURE
For a network consisting of many relatively short roads
contained in a well-defined study area (as would be the case at
an industrial plant), it is recommended that one collect a sample
for each 0.8 km (0.5 mi) length, or portion thereof, for each
major road segment. For a 1 km (0.6 mi) long segment, then,
two samples are recommended. As before, the term "road segment"
refers to the length of road between intersections (the nodes of
the network) with other paved or unpaved roads.
For longer roads in spatially heterogeneous study areas, it
is recommended that one collect a sample for each 4.8 km (3 mi)
of sampled road length. Create a composite sample from a minimum
of three incremental samples. Collect the first increment at a
random location within the first 0.8 km (0.5 mi), with additional
increments taken from each remaining 0.8 km (0.5 mi) of the road
up to a maximum length of 4.8 km (3 mi.) For a road less than
2.4 km (1.5 mi) in length, an acceptable method for selecting
sites for the increments is based on drawing three random numbers
(xl, x2, x3) between zero and the length (See Figure A-3).
Random numbers may be obtained from tabulations in statistical
reference books, or scientific calculators may be used to
generate pseudorandom numbers. See Figure A-3.
The following steps describe the collection method for
samples (increments).
1. Ensure that the site offers an unobstructed view of
traffic and that sampling personnel are visible to
drivers. If the road is heavily traveled, use one crew
member to "spot" and route traffic safely around
A-10
-------
8km (5 Mi.) of similar road type
H
H
Increment 1
8
Figure A-3. Sampling locations for paved roads.
-------
another person collecting the surface sample
(increment).
Using string or other suitable markers, mark the
sampling width across the road. (WARNING: Do not mark
the collection area with a chalk line or in any other
method likely to introduce fine material into the
sample.) The widths may be varied between 0.3 m (1 ft)
for visibly dirty roads and 3 m (10 ft) for clean
roads. When using an industrial-type vacuum to sample
lightly loaded roads, a width greater than 3 m (10 ft)
may be necessary to meet sample specifications unless
increments are being combined.
If large, loose material is present on the surface, it
should be collected with a whisk broom and dustpan.
NOTE: Collect material only from the portion of the
road over which the wheels and carriages routinely
travel (i.e., not from berms or any "mounds" along the
road centerline). On roads with painted side markings,
collect material "from white line to white line" (but
avoid centerline mounds). Store the swept material in
a clean, labeled container of suitable size (such as a
metal or plastic 19 L [5 gal] bucket) with a scalable
polyethylene liner. Increments for the same sample may
be mixed within the container.
Vacuum sweep the collection area using a portable
'vacuum cleaner fitted with an empty tared
(i.e., preweighed) filter bag. NOTE: Collect material
only from the portion of the road over which the wheels
and carriages routinely travel (i.e., not from berms or
any "mounds" along the road centerline). On roads with
painted side markings, collect material "from white
line to white line" (but avoid centerline mounds). The
same filter bag may be used for different increments
for one sample. For heavily loaded roads, more than
one filter bag may be required for a sample
(increment).
A-12
-------
5. Carefully remove the bag from the vacuum sweeper and
check for tears or leaks. If necessary, reduce samples
(using the procedure in Appendix B) from broom sweeping
to a size amenable for analysis. Seal broom-swept
material in a clean, labeled plastic jar for transport
(alternatively, the swept material may be placed in the
vacuum filter bag). Fold the unused portion of the
filter bag, wrap a rubber band around the folded bag,
and store the bag for transport.
6. Record the required information on the sample
collection sheet (Figure A-4).
SAMPLE SPECIFICATIONS
Broom swept samples (if. collected) should be at least 400 g
(1 Ib) for silt and moisture analysis. The vacuum swept sample
should be at least 200 g (0.5 Ib); in addition, the exposed
filter bag weight should be at least 3 to 5 times greater than
the weight of the empty filter bag. Additional increments should
be taken until these sample mass goals have been achieved.
A-13
-------
Date Collected
Sampling location*
SAMPLING DATA FOR PAVED ROADS
Recorded by
No of Lanes
Surface type (e.g., asphalt, concrete, etc.)
Surface condition (e.g., good, rutted, etc.)
•Use code given on plant or road map for segment identification. Indicate sampling location
on map.
METHOD:
1. Sampling device: portable vacuum cleaner (whisk broom and dustpan if heavy loading present)
2. Sampling depth: loose surface material (do not sample curb areas or other untravelled portions
of the road)
3. Sample container: tared and numbered vacuum cleaner bags (bucket with scalable liner if heavy
loading present)
4. Gross sample specifications: Vacuum swept samples should be at least 200 g (0.5 Ib), with the
exposed filter bag weight should be at least 3 to 5 times greater than the empty bag tare
weight.
Refer to procedure described in Section 2.0 of "Appendix D to AP-42" for more detailed instructions.
Indicate any deviations from the above
SAMPLING DATA COLLECTED:
Sample No.
Vacuum Bag
ID Tare Wgt (g)
Sampling Surface
Dimensions
(Ixw)
Time
Mass of
Broom-Swept
Sample +
+ Enter "0" if no broom sweeping is performed.
Figure A-4. Example data form for paved roads.
A-14
-------
SECTION A.3
SAMPLES FROM STORAGE PILES
OBJECTIVE
The overall objective of an storage pile sampling and
analysis program is to inventory particulate matter emissions
from the storage and handling of materials. This is typically
done by
1. collecting "representative" samples of the material,
2. analyzing the samples to determine moisture and silt
contents, and,
3. combining analytical results with material throughput
and meteorological information in an emission factor
model.
As initial steps in storage pile sampling, it is necessary
to decide (a) what emission mechanisms—material load-in to and
load-out from the pile, wind erosion of the piles—are of interest
and (b) how many samples can be collected and analyzed given time
and monetary constraints. (In general, annual average PM
emissions from material handling can be expected to be much
greater than those from wind erosion.) For an industrial plant,
it is recommended that at least one sample be collected for each
major type of material handled within the facility.
In a program to characterize load-in emissions,
representative samples should be collected from the material
recently loaded into the pile. Similarly, representative samples
for load-out emissions should be collected from the areas that
are worked by the load-out equipment such as front end loaders or
clamshells. For most "active" piles (i.e., those with frequent
load-in and load-out operations), one sample may be considered
representative of both loaded-in and loaded-out materials. Wind
erosion material samples should be representative of the surfaces
exposed to the wind.
A-15
-------
In general, samples consist of increments taken from all
exposed areas of the pile (i.e., top, middle, and bottom). If
the same material is stored in several piles, it is recommended
that piles containing at least 25% of the amount in storage be
sampled. For large piles that are common in industrial settings
(e.g., quarries, iron and steel plants), access to some portions
may be impossible for the person collecting the sample. In that
case, increments should be taken no higher than it is practical
for a person to climb carrying a shovel and a pail.
PROCEDURE
The following steps describe the method for collecting
samples from storage piles:
1. Sketch plan and elevation views of the pile. Indicate
if any portion is inaccessible. Use the sketch to plan
where the N increments will be taken by dividing the
perimeter into N-l roughly equivalent segments.
a. For a large pile, collect a minimum of
10 increments as near to the mid-height of the
pile as practical.
b. For a small pile, a sample should consist of a
minimum of 6 increments evenly distributed among
the top, middle, and bottom.
"Small" or "large" piles, for practical purposes, may
be defined as those piles which can or cannot,
respectively, be scaled by a person carrying a shovel
and pail.
2. Collect material with a straight-point shovel or a
small garden spade and store the increments in a clean,
labeled container of suitable size (such as a metal or
plastic 19 L [5 gal] bucket) with a scalable
polyethylene liner. Depending upon the ultimate goals
of the sampling program, choose one of the following
procedures:
a. To characterize emissions from material handling
operations at an active pile, take increments from
the portions of the pile which most recently had
A-16
-------
material added and removed. Collect: the material
with a shovel to a depth of 10 to 15 cm (4 to
6 in). Do not deliberately avoid larger pieces of
aggregate present on the surface.
b. To characterize handling emissions from an
inactive pile, obtain'increments of the core
material from a 1 m (3 ft) depth in the pile. A
2 m (6 ft) long sampling tube with a diameter at
least 10 times the diameter of the largest
particle being sampled is recommended for these
samples. Note that, for piles containing large
particles, the diameter recommendation may be
impractical.
c. If characterization of wind erosion (rather than
material handling) is the goal of the sampling
program, collect the increments by skimming the
surface in an upwards direction. The depth of the
sample should be 2.5 cm (1 in) or the diameter of
the largest particle, whichever is less. Do not
deliberately avoid collecting larger pieces of
aggregate present on the surface.
In most instances, collection method (a) should be selected.
3. Record the required information on the sample
collection sheet (Figure A-5). Note the space for
deviations from the summarized method.
SAMPLE SPECIFICATIONS
For any of the procedures, the sample mass collected should
be at least 5 kg (10 Ib). When most materials are sampled with
procedures 2.a or 2.b, ten increments normally result in a sample
of at least 2.3 kg (50 Ib) . Note that storage pile samples
usually require splitting to a size more amenable to laboratory
analysis.
A-17
-------
Date Collected
SAMPLING DATA FOR STORAGE PILES
Recorded by
Type of Material samples
Sampling location:*
METHOD:
1. Sampling device: pointed shovel (hollow sampling tube if inactive pile is to be sampled)
2. Sample depth:
For material handling of active piles: 10-15 cm (4-6 in)
For material handling of inactive piles: 1 m (3 ft)
For wind erosion samples: 2.5 cm (1 in) or depth of the largest particle (whichever is less)
3. Sample container: bucket with scalable liner
4. Gross sample specifications:
For material handling of active or inactive piles: minimum of 6 increments with total sample
weight of 5 kg (10 Ib) [10 increments totalling 23 kg (50 Ib) are recommended]
For wind erosion samples: Minimum of 6 increments with total sample weight of 5 kg (10 Ib)
Refer to procedure described in Section 3.0 of "Appendix D to AP-42" for more detailed instructions.
Indicate any deviations from the above
SAMPLING DATA COLLECTED:
Sample No.
Time
Location* of Sample
Collection
Device Used
S/T**
Depth
Mass of
Sample
•Use code given of plant or area map for pile/sample identification. Indicate each sampling location
on map.
Figure A-5. Example data form for storage piles,
A-18
-------
APPENDIX B
PROCEDURES FOR ANALYZING SURFACE AND BULK
MATERIALS SAMPLES
This appendix discusses procedures recommended for the analysis
of samples collected from paved and unpaved surfaces and from
bulk storage piles. (Appendix B presents procedures for the
collection of these samples.) Recommended procedures are based
on a review of American Society for Testing and Materials (ASTM)
methods,1 such as C-136 (sieve analysis) or D-2216 (moisture
content). Recommendations follow ASTM standards where practical,
and where not, the effort was made to develop procedures
consistent with the intent of the pertinent ASTM standards.
B-l
-------
left blank for production
B-2
-------
SECTION B.I
SAMPLE SPLITTING
OBJECTIVE
The collection procedures presented in Appendix A can result
in samples that need to be reduced in size prior to laboratory
analysis. Often, samples are unwieldy and field splitting is
advisable prior to transport of the samples.
The size of the laboratory sample is important. Too little
sample will not be representative and too much sample will be
unwieldy. 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 for
subsequent silt analysis is to have sufficient coarse and fine
portions to be representative of the material and to allow
sufficient mass on each sieve so that the weighing is accurate.
A laboratory sample of 400 to 1,600 g is recommended because of
the scales normally available (1.6 to 2.6 kg capacities). A
larger sample than this may produce "screen blinding" for the
20 cm (8 in) diameter screens normally available for silt
analysis. Screen blinding can also occur for small samples of
finer texture. Finally, the sample mass should be such that it
can be spread out in a reasonably sized drying pan to a depth of
< 2.5 cm (1 in). The appendix presents the result of a limited
laboratory study that addresses sample size issues.
Two methods are recommended for sample splitting—riffles,
and coning and quartering. Both procedures are described below.
PROCEDURE
Figure B-l shows two riffles for sample division. Riffle
slot widths should be at least three times the size of the
B-3
-------
FEED CHUTE
RIFFLE SAMPLER
(A)
RIFFLE BUCKET AND
SEPARATE FEED CHUTE
STRAND
(B)
Figure B-l. Sample riffle dividers.
B-4
-------
largest aggregate in the material being divided. The following
quote from ASTM Standard Method D2013-72 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). 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, 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.1
Coning and quartering is a simple procedure which is
applicable to all powdered materials and to sample sizes ranging
from a few grams to several hundred pounds.2 Oversized material,
defined as > 0.6 mm (3/8 in) in diameter, should be removed prior
to quartering and weighed in a tared container.
Preferably, perform the coning and quartering operation on a
floor covered with clean 10-mil plastic. Take care that the
material is not contaminated by anything on the floor or that a
portion is not lost through cracks or holes. 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.
The procedure for coning and quartering is illustrated in
Figure B-2. The following steps describe the procedure.
1. «Mix the material and shovel it into a neat cone.
B-5
-------
Figure B-2. Procedure for coning and quartering.
B-6
-------
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 0.4 to 1.8 kg (1 to
4 Ib) .
B-7
-------
left blank for production
B-8
-------
SECTION B.2
MOISTURE ANALYSIS
Paved road samples generally are not oven dried because
vacuum filter bags are used to collect the samples. After the
sample has been recovered by dissection of the bag, it is
combined with any broom swept material for silt analysis. All
other sample types are oven dried to determine moisture content
prior to sieving.
PROCEDURE
1. Preheat the oven to approximately 110°C (230°F). Record
oven temperature.
2. Record the make, capacity, and smallest division of the
scale.
3., Weigh the empty laboratory sample containers which will be
placed in the oven to determine their tare weight. Weigh
containers with the lids on if they have lids. Record the
tare weight(s). Check zero before each weighing.
4. Weigh the laboratory sample(s) in the container(s). For
materials with high moisture content, ensure that any
standing moisture is included in the laboratory sample
container. Record the combined weight(s).. Check zero
before each weighing.
5. Place sample in oven and dry overnight. Materials composed
of hydrated minerals or organic material like coal and
certain soils should be dried for only l-i/2 h. •
6. Remove sample container from oven and (a) weigh immediately
if uncovered, being careful of the hot container; or
(b) place the tight-fitting lid on the container and let
cool before weighing. Record the combined sample and
container weight(s). Check zero reading on the balance
before weighing.
B-9
-------
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.
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.
(See Figure B-3.)
B-10
-------
Sample:
Material:
Split sample balance:
Make:
Capacity:
Smallest division:
Total sample weight:
[Excl. container]
No. of spills:
Split sample weight (before drying)
Pan + sampler:
Pan:
Wet sample:
Oven temperature:
Date in Date out
Time in
Date out
Drying time:
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. Example moisture, analysis form.
B-ll
-------
left blank for production
B-12
-------
SECTION B.3
SILT ANALYSIS
OBJECTIVE
Several open dust emission factors have been found to be
correlated with the silt (< 200 mesh) content of the material
being disturbed. The basic procedure for silt content
determination is mechanical, dry sieving. For sources other than
paved roads, the same sample which was oven-dried to determine
moisture content is then mechanically sieved.
For paved road samples, the broom swept particles and the
vacuum swept dust are individually weighed on a beam balance.
The broom-swept particles are weighed in a container. The vacuum
swept dust is weighed in the vacuum bag which was tared prior to
sample collection. After weighing the sample to calculate total
surface dust loading on the traveled lanes, combine the broom-
swept particles and the vacuum swept dust. The composite sample
is usually small and may not require splitting in preparation for
sieving.
PROCEDURE
1. Select the appropriate 20 cm (8-in) diameter, 5 cm (2-in)
deep sieve sizes. Recommended U.S. Standard Series sizes
are: 3/8 in, No. 4, No. 40, No. 100, No. 140, No. 200, and
a pan. Comparable Tyler Series sizes can also be utilized.
The No. 20 and the No. 200 are mandatory. The others can be
varied if 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 without the tapping function.
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
B-13
-------
handling the screen roughly.
4. Obtain a scale (capacity of at least 1,600 g or 10 Ib) and
record make, capacity, smallest division, date of last
calibration, and accuracy.
5. Weigh the sieves and pan to determine tare weights. 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 (preferably immediately
after moisture analysis) into the top sieve. The sample
should weigh between ~ 400 and 1,600 g (0.9 to 3.5 Ib).
This amount will vary for finely textured materials; 100 to
300 g may be sufficient with 90% of the sample passes a
No. 8 (2.36 mm) 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 sieving device and
sieve for 10 min. Remove pan containing minus No. 200 and
weigh. Repeat the sieving in 10-min intervals until the
difference between two successive pan sample weighings
(where the tare weight of the pan has been subtracted) is
less than 3.0%. Do not sieve longer than 40 min.
8. Weight each sieve and its contents and record the weight.
Check the zero reading on the balance before every weighing.
9. Collect the laboratory sample and place the sample in a
separate container if further analysis is expected.
10. Calculate the percent of mass less than the 200 mesh screen
(75 /zm) . This is the silt content. See Figure B-4.
B-14
-------
Sample No.:
Material:
Material weight (after drying)
Pan + material:
Pan:
Split sample balance;
Make: ,
Capacity:
Smallest division:
Dry sample:
Final weight;
Net weight <200 mesh
% silt = * 100
Total net weight
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)
Rnal weight
(screen +
sample)
Net weight
(sample)
%
•
Figure B-4. Example silt analysis form.
B-15
-------
left blank for production
B-16
-------
SECTION B.4
REFERENCES
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-17
-------
APPENDIX C
INDUSTRIAL VEHICLE WEIGHTS
TABLE C-l. INDUSTRIAL VEHICLE WEIGHTS
Typical equipment weight analysis from equipment specifications
Provided by Catepillar, Inc.
FORKLIFT:
Series
M Series: Cusion tire-electric
F Series: Pneumatic tire-electric
V Series: Pneumatic tire-gas/
LP/diesel
T Series: Cusion tire-gas/LP/
diesel
El Series: Pneumatic tire-gas/
diesel
No. of
wheels
4
4
4
4
4
No. of
models
13
8
25
22
7
Shipping weight, Ib
Min
6,080
6,400
5,700
5,600
10,700
Med
9,500
8,850
13,100
11,400
12,700
Max
16,000
10,550
37,200
19,700
16,000
Rated capacity, Ib
Min
2,500
2,500
2,500
2,500
4,000
Med
5,000
4,000
8,000
6,000
6,000
Max
10,000
6,000
33,000
15,000
8,000
Total
loaded
weight, Ib
12,000
10,850
17,100
14,400
15,700
Average: 14,010 Ib
6,361 kg
For each series, typical loaded equipment weight equals median shipping weight plus half of median rated capacity (assuming loading at
rated capacity for half the time of equipment operation).
WHEEL LOADER (FRONT-END LOADER):
Model
926E
936E
950F
966F
980F
988B
No. of wheels
4
4
4
4
4
4
Operating weight,
Ib
20,946
26,929
35,668
45,500
61,046
95,602
Lower bucket
capacity, yd5
2
3
3
4
5
7
Higher bucket
capacity, yd1
' 3
3
4
5
7
8
Estimated bucket
load, Ib
6,250
7,500
10,000
12,500
17,500
20,625
Typical loaded
equipment
weight, Ib
24,071
30,679
40,668
51,750
69,796
105,915
Average: 53,813 Ib
24,431 kg
Estimated bucket load is based on 2,500 Ib per cubic yard of higher bucket capacity.
For each model, typical loaded equipment weight equals operating weight plus half of estimated bucket load (assuming loading at bucket
capacity for half the time of equipment operation).
C-l
-------
APPENDIX D
METEOROLOGICAL DATA FOR SECONDARY LEAD SMELTER LOCATIONS
D-l
-------
TABLE D-l. METEOROLOGICAL DATA FOR SECONDARY LEAD SMELTER LOCATIONS
Facility name, city, State
Interstate Lead Company,
Inc., Leeds, AL
Sanders Lead Company,
Inc., Troy, AL
GNB, Inc., Vemon, CA
RSR Corp., City of
Industry, CA
Gulf Coast Recycling,
Inc., Tampa, FL
GNB, Inc., Columbus,
GA
Chemetco, Inc., Hartford,
IL
Exide Corp., Muncie, IN
Refined Metals Corp.,
Beech Grove, TN
RSR Corp., Indianapolis,
IN
Butler-McDonald,
Indianapolis, IN
Metals Control of Kansas,
Hfflsboro, KS
Delatte Metals,
Ponchatoula, LA
Schuylkill Metals Corp.,
Baton Rouge, LA
Climates of the States8
Meteorological
station location
Birmingham, AL
Vlunic. Airport
Montgomery, AL
Los Angeles,
CA-Civic Center
Los Angeles,
CA-Civic Center
Tampa, FL
Columbus, GA
St. Louis, MO
Indianapolis, IN
Memphis, TN
Indianapolis, IN
Indianapolis, IN
Wichita, KS
Baton Rouge, LA
Baton Rouge, LA
Mean No. of
d/yr of precip.
>0.01 in.
117
108
36
36
107
111
110
124
106
124
124
85
108
108
Annual mean
wind speed, mph
7.3
6.7
6.2
6.2
8.6
6.7
9.6
9.6
9.0
9.6
9.6
12.4
7.7
7.7
Annual mean
wind speed,
m/sec
3.3
3.0
2.8
2.8
3.8
3.0
4.3
4.3
4.0
4.3
4.3
5.5
3.4
3.4
Climatic Atlasb
Meteorological
station
Birmingham, AL
Montgomery, AL
Los Angeles, CA
Los Angeles, CA
Tampa, FL
Macon, GA
St. Louis, MO
Indianapolis, IN
Memphis, TN
Indianapolis, IN
Indianapolis, IN
Wichita, KS
Baton Rouge, LA
Baton Rouge, LA
Percentage of
time wind
speed exceeds
12 mph
21
14
12
12
18
18
25
35
26
35
35
53
20
20
Mean wind
speed, mph
7.9
6.9
6.8
6.8
8.8
8.9
9.3
10.8
9.4
10.8
10.8
13.7
8.3
8.3
-------
TABLE D-l. (continued)
7acility name, city, State
Gopher Smelting and
defining Company,
lagan, MN
Doe Run Company, Boss,
MO
Schuylkill Metals Corp.,
Forest City, MO
RSR Corp., Middletown,
NY
Beneficial Recycling
Company, Charlotte, NC
Master Metals, Inc.,
Cleveland, OH
PBX, Inc., Norwalk, OH
Metal Control, Muskogee,
OK
East Penn Manufacturing
Company, Lyon Station,
PA
Exide Corp., Reading, PA
Federated-Fry Metals,
Altona, PA
General Smelting and
Refining, Inc., College
Grove, TN
Climates of the States3
Meteorological
station location
rfinneapolis-St.
Paul, MN
St. Louis, MO
Kansas City,
VlO-International
Airport
Newark, NJ
Charlotte, NC
Cleveland, OH
Mansfield, OH
Tulsa, OK
Allentown, PA
Allentown, PA
Harrisburg, PA
Nashville, TN
Mean No. of
d/yr of precip.
>0.01 in.
114
110
104
121
112
155
139
89
124
124
121
119
Annual mean
wind speed, mph
10.5
9.6
10.6
10.2
7.5
10.8
11.0
10.5
9.3
9.3
7.7
8.0
Annual mean
wind speed,
ml sec
4.7
4.3
4.7
4.6
3.4
4.8
4.9
4.7
4.2
4.2
3.4
3.6
Climatic Atlasb
Meteorological
station
Minneapolis, MN
St. Louis, MO
Kansas City, MO
Newark, NJ
Charlotte, NC
Cleveland, OH
Akron-Canton, OH
Tulsa, OK
Philadelphia, PA
Philadelphia, PA
Harrisburg, PA
Nashville, TN
Percentage of
time wind
speed exceeds
12 mph
39
25
29
30
16
40
32
34
27
27
17
16
Mean wind
speed, mph
11.2
9.3
9.8
9.8
7.9
11.6
10.4
10.6
9.6
9.6
7.3
7.2
-------
TABLE D-l. (continued)
Facility name, city, State
Refined Metals Corp.,
Memphis, TN
Ross Metals, Inc.,
Mossville, TN
GNB, Inc., Frisco, TX
Tejas Resources, Terrell,
TX
Climates of the States9
Meteorological
station location
Memphis, TN
Memphis, TN
Dallas-Ft. Worth,
TX
Dallas-Ft. Worth,
TX
Mean No. of
d/yr of precip.
>0.01 in.
106
106
78
78
Minimum: 36
Maximum: 155
Mean: 106.8
Std. Dev.: 24.6
Annual mean
wind speed, mph
9.0
9.0
10.8
10.8
9.05
Annual mean
wind speed,
m/sec
4.0
4.0
4.8
4.8
2.8
5.5
4.05
0.7
Climatic Atlas'5
Meteorological
station
Memphis, TN
Memphis, TN
Dallas, TX
Dallas, TX
Percentage of
time wind
speed exceeds
12 mph
26
26
38
38
12
53
26.8
9.6
Mean wind
speed, mph
9.4
9.4
11
11
9.42
o
I
aReference 1.
Reference 2.
-------
REFERENCES FOR APPENDIX D
1. Climates of the States, Third Edition, Volumes 1 and 2, Gale
Research Company, Detroit, Michigan, 1985.
2. Climatic Atlas of the United States, U.S. Department of
Commerce, 1968.
D-5
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APPENDIX E
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, 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.
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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. Fugitive 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)
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 fugitive dust
sources and the emission factors for process fugitive sources
presented in Section 2.1 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.
Ept, = 1.0 x iOA (C) (sL)065 (W)1-5 (VMT)
where:
Epb = lead emissions, Ib/yr;
C = average percent of lead by weight in the silt
fraction;
sL = road surface silt loading, g/m2;
W = average vehicle weight, tons; and
VMT = vehicle miles travelled per year.
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M
to
I
N
1 Main plant roadway
2 Noilh plant yard
3 Casting building
4 Raw material storage
5 Battery breaking building
6 South plant yard
Figure E-l. Plot plan for Facility A.1
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Slag storage pile (handling)
Ep., = 7.7 x 10'6 (C) — (P)
\M 1.4
IY1
where:
Epb = lead emissions, Ib/yr;
C = percent by weight of lead in the silt fraction;
U = mean wind speed, mph;
M = material moisture content, percent; and
P = process rate, ton/yr.
Slag storage and north yard (wind erosion)
Ep,, - 3.2 X 10^ (C) (s) (365-p) (f) (A)
where:
Epb = lead emissions, Ib/day;
C = lead content of surface, percent;
s = silt content, percent;
p = number of days with >0.0l 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
Ept = 3.2 P to 7.0 P
where:
Ept, = lead emission rate, Ib/yr, and
P = production rate (tons Pb produced/yr).
Refining kettle
Epb = 0.012 P
where:
£,,, = lead emission rate, Ib/yr, and
P = finished lead production rate, tons/yr.
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Casting
Ej,, = 0.0014 P
where:
Ept, = 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 performing 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. 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 10 g/m2 for the road and 32g/m2
for the plant yard. These dust loadings convert to salt loadings
of 1.5 g/m2 for the roadway and 6.7 g/m2 for the plant yard.
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 o.n plant
records and conversations with plant personnel. The average
number of delivery trucks that trave.l on plant roads are shown in
Table E-l. The travel pattern results in approximately
3,900 trips per year. Examination of plant maps indicates that
each round trip is about 400 ft or 0.076 miles in length. Hence,
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total vehicle miles traveled per year is about 295. 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 are in
motion about 10 percent of the time and at speeds of about
5 mi/hr. These vehicles account for about 20 vehicle miles per
day, or about 7,300 vehicle miles per year.
TABLE E-l. SUMMARY OF DELIVERY TRUCK TRAFFIC AT FACILITY A
Material
1.
2.
3.
4.
5.
6.
Batteries
Battery scrap
Coke
Scrap iron
Lime stone
Lead ingots to customer
Frequency
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).
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
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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 lead fugitive dust 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 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 E-2.
REFERENCES FOR APPENDIX E
1. 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, U. S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, July 1986, p. 4-6.
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TABLE E-2. CALCULATION OF FUGITIVE EMISSION RATES
Raw material and product delivery trucks
Ep,, = 1.0 X 10"* (C) (sL)065 (W)1-5 (VMT)
= 1.0 X 10" (34) (1.5)065 (40)1'5 (295)
= 330 Ib/yr
Internal material transfer
En, - 1.0 x 10" (C) (sL)065 (W)1-5 (VMT)
= 1.0 X 10" (32) (6.7)065 (12)1-5 (7,300)
= 3,340 Ib/yr
— Slag storage pile -r handling
JPb
7.7 X 10'6 (C) — (P)
M
= 7.7 X 10'6 (42) *•*' (8,600)
(3)14
=4.8 Ib/yr
— Slag storage pile: wind erosion
E^ = 3.2 X 10-6 (C) (s) (365 - p) (f) (A)
= 3.2 x ID"6 (42) (12) (365 - 115) (1.2) (0.034)
= 0.016 lb/day
=6.0 Ib/yr
— North yard: wind erosion
£„, = 3.2 X 10^ (C) (s) (365 - p) (f) (A)
= 3.2 X ID"6 (43) (13) (365 - 115) (0.4) (0.25)
= 0.045 lb/day
= 16.4 Ib/yr
Blast furnace charging and tapping
E = 5.1 P
= 5.1 (23,000)
= 117,300 Ib/yr
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TABLE E-2. (continued)
— 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
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