United States
Environmental Protection
Agency
EPA-600/2-90-044
Control Technology
Center
Research Triangle Park NC 27711 August 1990
EMISSION FACTORS
FOR IRON FOUNDRIES--
CRITERIA AND TOXIC POLLUTANTS
PREPARED FOR:
Hamilton County
Chattanooga. Tennessee
control ^technology center
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development. U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
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The nine series are:
1. Environmental Health Effects Research
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3. Ecological Research
4. Environmental Monitoring
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This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
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This report has been reviewed by the U.S. Environmental Protection Agency, and
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This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-90-044
August 1990
EMISSION FACTORS FOR IRON FOUNDRIES
CRITERIA AND TOXIC POLLUTANTS
by
Gerhard Gschwandtner and Susan Fairchild
E.H. Pechan & Associates, Inc.
3514 University Drive
Durham, North Carolina 27707
EPA Contract No. 68-D9-0168
Work Assignment No. 5
EPA Project Officer:
Robert C. McCrillis
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
Prepared for:
U.S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460
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CONTROL TECHNOLOGY CENTER
SPONSORED BY:
Emission Standards Division
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Air and Energy Engineering Research Laboratory
Office of Research And Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Center for Environmental Research Information
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
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FOREWORD
During the past several years, attention has mostly focused
on emissions of criteria pollutants. These pollutants include
particulate matter, sulfur dioxide, carbon dioxide, nitrogen
oxides, volatile organic compounds, and lead. More recently,
attention has focused on air toxic pollutants. These pollutants
include many different compounds. This report summarizes the
information available for both types of pollutants for iron
foundry sources. It serves as a guide for estimating the
emissions when emission measurements are not available.
ill
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ABSTRACT
This report provides a comprehensive list of criteria
toxic pollutant emission factors for. sources commonly found in
iron foundries. Emission factors are identified for process
sources and process fugitive emissions. The emission factors
represent uncontrolled emissions. These factors may be used to
estimate emissions when site-specific information is not
available.
IV
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TABLE OF CONTENTS
Foreword iii
Abstract iv
Figures vi
Tables vii
1. Introduction 1
2. Pollutant Emitting Processes 2
Raw Material Handling and Preparation 2
Metal Melting 5
Cupolas 5
Electric Arc Furnaces 6
Electric Induction Furnaces 6
Inoculation 7
Mold and Core Production 7
Casting and Finishing 8
Greensand Shakeout 9
3. Criteria Pollutant Emission Factors 11
4. Toxic Pollutant Emission Factors 15
Metal Melting 15
Cupolas 15
Electric Arc Furnaces 19
Electric Induction Furnaces 20
Mold and Core Production 22
Inoculation 25
Pouring 25
Greensand Shakeout 26
Air Toxic Emission Factor Rating 26
References 28
Appendix
A. AP-42 Section on Gray Iron Foundries A-l
B. Toxic Air Pollutant Emission Factors for Iron
Foundries B-l
C. Criteria Air Pollutant Emission Factors for Gray
Iron Foundries C-l
D. Threshold Limit Values and Biological Exposure
Indices for 1989 - 1990 D-l
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FIGURES
Number ^~~
1 Emission Points in a Typical Iron Foundry-
4
2 Typical Iron Foundry Diagram
A-3
7.10-1 Typical Iron Foundry Diagram
7.10-2 Emission Points in a Typical Iron Foundry. . A~4
7.10-3 Particle Size Distribution for Uncontrolled
Cupola A
7.10-4 Particle Size Distribution for Baghouse
Controlled Cupola A-15
7.10-5 Particle Size Distribution for Venturi Scrubber
Controlled Cupola A-16
7.10-6 Particle Size Distribution for Uncontrolled
Electric Arc Furnace A-17
7.10-7 Particle Size Distribution for Uncontrolled
Pouring and Cooling A-18
7.10-8 Particle Size Distribution for Uncontrolled
Shakeout A-19
VI
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TABLES
Number Page
1 Chemical Composition of Ferrous Castings by
Percentage 5
2 Criteria Emissions, mg/Mg Metal Melted 14
3 Organic Emissions, mg/Mg Iron Produced 16
4 Inorganic Emissions, mg/Mg Iron Produced .... 17
5 Induction Furnace Emissions 22
6 Some Foundry-Atmosphere Contaminants Evolved
During Mold and Core Making, Casting, and
Cooling 24
7.10-1 Chemical Composition of Ferrous Castings by
Percentage A-5
7.10-2 Emission Factors for Gray Iron Furnaces A-9
7.10-3 Gaseous and Lead Emission Factors for Gray Iron
Foundries A-10
7.10-4 Particulate Emission Factors for Ancillary
Process Operations and Fugitive Sources at Gray
Iron Foundries A-11
7.10-5 Particle Size Distribution Data and Emission
Factors for Gray Iron Foundries A-12
VII
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SECTION 1
INTRODUCTION
Iron foundries have been identified in certain areas of the
country to be potentially significant sources of air pollution.
The Control Technology Center of the U.S. Environmental
Protection Agency, in response to a request for air toxic
emission factors by the Hamilton County Air Pollution Control
Bureau of Chattanooga, Tennessee, commissioned this report. The
report is an attempt to compile all current emission factor
information that may be used by state and local agencies in
estimating emissions from iron foundries. This report is a
follow-on to a previous report on emission factors for iron and
steel manufacturing facilities.
The objective of this study is to provide a comprehensive
set of emission factors for sources of both criteria and toxic
air pollutants in *gray' and ductile iron foundries. Emission
factors are identified for process sources, process fugitive and
open source fugitive emissions. The emission factors are not
specific to any one facility.
During the past several years, attention has mostly focused
on emissions of criteria pollutants. These pollutants include
particulate matter, sulfur dioxide, carbon dioxide, nitrogen
oxide, volatile organic compounds, and lead. More recently,
attention has focused on air toxic pollutants. These pollutants
include many different compounds. This report summarizes the
information available for both types of pollutants. It serves as
a guide for estimating the emissions when emission measurements
are not available.
This study was accomplished by conducting a literature
search of 'the library of the U.S. EPA and the American
Foundrymen's Society. Articles were reviewed for any information
that could be used to develop emission factors for any of the
processes associated with iron foundries. The emission factors
are presented in terms of an average value or range of values
together with a rating of quality or reliability.
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SECTION 2
POLLUTANT EMITTING PROCESSES
Iron foundries produce iron castings from scrap iron, pig
iron, and foundry returns by melting, alloying, and molding. The
major operations include 1) raw material handling and
preparation, 2) metal melting, 3) mold and core production, and
4) casting and finishing.
RAW MATERIAL HANDLING AND PREPARATION
Handling operations include receiving, unloading, storing,
and conveying of all raw materials for both furnace charging and
mold and core preparation. The major groups of raw materials
required for furnace charging are metallics, fluxes, and fuels.
Metallic raw materials include pig iron, iron and steel scrap,
foundry returns, and metal turnings. Fluxes include carbonates
(limestone, dolomite), fluoride (fluorspar), and carbide
compounds (calcium carbide). Fuels include coal, oil, natural
gas, and coke. Coal, oil, and natural gas are used to fire
reverberatory furnaces. Coke, a derivative of coal, is used as a
fuel in cupola furnaces. Although not a true fuel, carbon
electrodes are required for heat production in electric arc
furnaces.
As shown in Figures 1 and 2, the raw materials, metallics,
and fluxes are added to the melting furnaces directly- For
electric induction furnaces, however, the scrap metal added to
the furnace charge must first be pretreated to remove any grease
and/or oil, which can cause explosions. Scrap metals may be
degreased with solvents, by centrifugation, or by preheating to
combust the organics.
In addition to the raw materials used to produce the molten
metal, a variety of materials are needed to prepare the sand
cores and molds used to form the iron castings. Virgin sand,
recycled sand and chemical additives are combined in a sand
handling system typically composed of receiving areas, conveyors,
storage silos and bins, mixers (sand mullers), core and mold
making machines, shakeout grates, sand cleaners, and sand
screening.
Raw materials are transported in ships, railroad cars,
trucks, and containers, and then are transferred by truck
loaders, and conveyors to both open piles and enclosed storage
areas. When needed, the raw materials are transferred from
storage to process areas by similar means.
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METAL
MELTING J*&
DUCTIIE IRON
IHHOCULAT10N
CASTING
SHAKEOUT
COOLING AND
CLEANING
CORE
MAKING
SAND
PREPARATION
Figure 1. Emission points in a typical iron foundry.
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Furnace Charge Preparation
Melting and Catling
Waite Sand
Polleim
Figure 2. Typical iron foundry diagram.
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METAL MELTING
The furnace charge includes metallics, fluxes, and fuels.
The composition of the charge depends upon the specific metal
characteristics required. Table 1 lists the different chemical
compositions of typical irons produced. The three most common
furnaces used in the gray iron foundry industry are cupolas,
electric arc, and electric induction furnaces.
TABLE 1. CHEMICAL COMPOSITION OF FERROUS CASTINGS
BY PERCENTAGES
Gray Malleable iron
Element iron (as white iron;
Carbon 2.5-4.0 1.8-3.6
Silicon 1.0 - 3.0 0.5 - 1.9
Magnesium
Manganese 0.40-1.0 0.25-0.80
Sulfur 0.05 - 0.25 0.06 - 0.20
Phosphorus 0.05-1.0 0.06-0.18
Ductile
) iron
3.0 - 4.0
1.4 - 2.0
0.01 - 1.0
0.5 - 0.8
<0.12
<0.15
Steel
<2.0a
0.2 - 0.8
0.5 - 1.0
<0.06
<0.05
'Steels are classified by carbon content: low carbon; <0.20
percent, medium carbon; 0.20 - 0.5 percent, high carbon; >0.50
percent.
Cupolas
The cupola, which is the major type of furnace used in the
foundry industry today, is typically a vertical cylindrical steel
shell with either a refractory lined or water cooled inner wall.
Refractory linings usually consist of silica brick, or dolomite
or magnesium brick. Water cooled linings, which involve
circulating water around the outer steel shell, are used to
protect the furnace wall from interior temperatures. The cupola
is charged at the top with alternate layers of coke, metallics,
and fluxes.
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The cupola is the only furnace type to use coke as a fuel;
combustion air used to burn the coke is introduced through
tuyeres located at the base of the cupola. Cupolas use either
cold blast air, air introduced at ambient temperature, or hot
blast air which may be heated with a regenerative system which
utilizes heat from the cupola exhaust gases to preheat the
combustion air.
Iron is melted by the burning coke and flows down the
cupola. As the melt proceeds, new charges are added at the top.
The flux removes non-metallic impurities in the iron to form
slag. Both the molten iron and the slag are removed through tap
holes at the bottom of the cupola. Periodically, the heat period
is completed, and the bottom of the cupola is opened to remove
the remaining unburned material.
Cupola capacities range from 1 to 27 megagrams per hour (1
to 30 tons per hour), with a few larger units approaching 90
megagrams per hour (100 tons per hour). Larger furnaces operate
continuously and are inspected and cleaned at the end of each
week or melting cycle.
Electric Arc Furnaces
Electric arc furnaces (EAF) are large, welded steel
cylindrical vessels equipped with a removable roof through which
three retractable carbon electrodes are inserted. The electrodes
are lowered through the roof of the furnace and are energized by
three phase alternating current, creating arcs that melt the
metallic charge with their heat. Additional heat is produced by
the resistance of the metal between the arc paths.
The most common method of charging an electric arc furnace
is by removing the roof and introducing the raw materials
directly. Alternative methods include introducing the charge
through a chute cut in the roof or through a side charging door
in the furnace shell. Once the melting cycle is complete, the
carbon electrodes are raised, and the roof is removed. The
vessel is tilted, and the molten iron is poured into a ladle.
Electric arc furnace capacities range from 0.23 to 59 megagrams
(0.25 to 65 tons). Nine to 11 pounds of electrode are consumed
per ton of metal melted.
Electric Induction Furnaces
Electric induction furnaces are either cylindrical or cup
shaped refractory lined vessels that are surrounded by electrical
coils which, when energized with high frequency alternating
current, produce a fluctuating electromagnetic field to heat the
metal charge. For safety reasons, the scrap metal added to the
furnace charge is cleaned and heated before being introduced into
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a furnace. Any oil or moisture on the scrap could cause an
explosion in the furnace. Induction furnaces are kept closed
except when charging, skimming, and tapping. The molten metal is
tapped by tilting and pouring through a hole in the side of the
vessels. Induction furnaces also may be used for metal refining
in conjunction with melting in other furnaces and for holding and
superheating the molten metal before pouring (casting).
The basic melting process operations are 1) furnace
charging, in which metal, scrap, alloys, carbon, and flux are
added to the furnace; 2) melting during which the furnace remains
closed; 3) backcharging, which involves the addition of more
metal and alloys, as needed; 4) refining and treating, during
which the chemical composition is adjusted to meet product
specifications; 5) slag removing; and 6) tapping molten metal
into a ladle or directly into molds-.
Inoculation
Inoculation is the process whereby magnesium and other
elements are added to molten gray iron, to produce ductile iron.
Ductile iron is formed as a steel matrix containing
spheroidal particles (or nodules) of graphite. Ordinary cast
iron, that is, gray cast iron, contains flakes of graphite. Each
flake acts as a crack, with the result that cast iron is well
known for its brittleness. Ductile irons are very silvery in
appearance and are noted for their tensile strength.
Inoculation of the molten iron has been accomplished in many
diverse ways, however the two most common methods are plunging
and pour over. In plunging, magnesium or a magnesium alloy is
loaded into a graphite "bell" which is plunged into the ladle of
molten iron. A turbulent reaction takes place as the magnesium
boils under the heat of the molten iron. As much as 65 percent
of the magnesium may be lost in the inoculation process, as the
magnesium vapor issuing from the iron ignites in air, creating
large amounts of smoke.
In the pour over method, the magnesium alloy is placed in
the bottom of a vessel and molten iron is poured over it.
Although this method produces more emissions and is less
efficient than plunging, it requires no capital equipment other
than air pollution control.
MOLD AND CORE PRODUCTION
Molds are forms used to shape the exterior of castings.
Cores are molded sand shapes used to make the internal voids in
castings. Cores are made by mixing sand with organic binders or
organic polymers, molding the sand into a core, and baking the
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core in an oven. Molds are prepared of a mixture of wet sand,
clay and organic additives to make the mold shapes, which are
usually dried with hot air. Cold setting binders are being used
more frequently in both core and mold production. The green sand
mold, the most common type, uses moist sand mixed with 4 to 6
percent clay (bentonite) for bonding. The mixture has a water
content of 4 to 5 percent. Added to the mixture, to prevent
casting defects from sand expansion when the hot metal is poured,
is about 5 percent organic material, such as sea coal (a
pulverized high volatility bituminous coal), wood flour, oat
hulls, pitch or similar organic matter.
Common types of gray iron cores include the following:
- Oil core, with typical sand binder of 1.0 percent core oil,
1.0 percent cereal, and 0 to 1 percent pitch or resin. Cured
by oven baking at 205 to 314°C (400 to 600°F), for 1 to 2
hours.
- Shell core, with sand binder typically 3 to 5 percent phenolic
and/or urea formaldehyde, with hexamine activator. Cured as a
thin layer on a heated metal pattern at 205 to 315°C (400 to
600°F), for 1 to 3 minutes.
Hot box core, with sand binder typically 3 to 5 percent furan
resin, with phosphoric acid activator. Cured as a solid core
in a heated metal pattern at 205 to 315°C (400 to 600°F), for
0.5 to 1.5 minutes.
Cold set core, with typical sand binder percents of 3 to 5
furan resin, with phosphoric acid activator; or 1 to 2 core
oil, with phosphoric acid activator. Hardens in the core box.
Cured for 0.5 to 3 hours.
Cold box core, with sand binder typically 1 to 3 percent of
each of two resins, activated by a nitrogen diluted gas.
Hardens when the green core is gassed in the box with
polyisocyanate in air. Cured for 10 to 30 seconds.
Used sand from castings shakeout is recycled to the sand
preparation area and cleaned to remove any clay or carbonaceous
buildup. The sand is then screened and reused to make new molds.
Because of process losses and discard of a certain amount of sand
because of contamination, makeup sand is added.
CASTING AND FINISHING
After the melting process, molten metal is tapped from the
furnace. Molten iron produced in cupolas is tapped from the
bottom of the furnace into a trough, then into a ladle. Iron
produced in electric arc and induction furnaces is poured
8
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directly into a ladle by tilting the furnace. At this point, the
molten iron may he treated with magnesium to produce ductile
iron. The magnet_um reacts with the molten iron to nodularize
the carbon in the molten metal, producing a less brittle iron.
At times, the molten metal may be inoculated with graphite to
adjust carbon content. The treated molten iron is then ladled
into molds and transported to a cooling area, where it solidifies
in the mold and is allowed to cool further before separation
(shakeout) from the mold and core sand.
In larger, more mechanized foundries, the molds are conveyed
automatically through a cooling tunnel. In simpler foundries,
molds are placed on an open floor space, and the molten iron is
poured into the molds and allowed to cool partially. Then the
molds are placed on a vibrating grid to shake the mold and core
sand loose from the casting. In the simpler foundries, molds,
core sand and castings are separated manually, and the sand from
the mold and core is then returned to the sand handling area.
When castings have cooled, any unwanted appendages, such as
spurs, gates, and risers, are removed. These appendages are
removed with oxygen torches, abrasive band saws, or friction
cutting tools. Hand hammers may be used, in less mechanized
foundries to knock the appendages off. The castings are then
subjected to abrasive blast cleaning and/or tumbling to remove
any remaining mold sand or scale.
Another step in the metal melting process involves removing
the slag in the furnace through a tapping hole or door. Since
the slag is lighter than molten iron, it remains atop the molten
iron and can be raked or poured out of cupola furnaces through
the slag hole located above the level of the molten iron.
Electric arc and induction furnaces are tilted backwards, and
their slag is removed through a slag door.
Greensand Shakeout
The most elementary method of removing castings from a mold
is to dump the mold, and hook, or pull out, the casting from the
sand. When significant production is required, the molds are
automatically inverted and dumped onto a vibrating grating which
shakes out the sand and separates the casting. The sand falls
through the grating and onto a conveyor belt which carries it to
the conditioning and reprocessing system. In some cases the
shakeout can be a long vibrating grate (30 meters), such as for
gasoline engine blocks and heads, where much internal core sand
must be removed. There are many variations of shakeout systems,
including heavy screen drums that rotate batches of castings and
long cylindrical perforated cylinders that tumble the parts and
process parts continuously.
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The shakeout has the potential to generate the most fumes of
the many foundry operations (except melting). By the time the
mold assembly reaches the shakeout, the bulk of the thermal
decomposition of the mold/core materials has occurred. The
products of thermal decomposition will tend to be lower molecular
weight materials and will vaporize and diffuse away from the hot
metal-sand interface into the cooler sand. Some of the organic
emissions will condense and adsorb on the cooler sand of the
mold. Most compounds with boiling points below 100°C will be
either emitted during the cooling process or undergo chemical
reactions and released as other pollutants. During shakeout, the
cooler sand comes into contact with the hot sand surrounding the
metal, and the metal itself. This causes a flash boiling,
thereby producing an emission of the pyrolysis products. In
addition, there will be a lesser amount of decomposition (than
occurs during pouring) of the organic constituents.
10
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SECTION 3
CRITERIA POLLUTANT EMISSION FACTORS
U.S. EPA publication AP-42, Compilation of Air Pollutant
Emission Factors provides the best guidance on emission factors
for criteria pollutants. The AP-42 section on iron foundries is
provided in Appendix A.
To help users understand the reliability and accuracy of AP-
42 emission factors, each table in an AP-42 section (and
sometimes individual factors within a table) is given a rating (A
through E, with A being the best) which reflects the quality and
the amount of data on which the emission factors are based.
In general, factors based on many observations or on more
widely accepted test procedures are assigned higher ratings. For
instance, an emission factor based on ten or more source tests on
different plants would likely get an A rating, if all tests were
conducted using a single valid reference measurement method or
equivalent technique. Conversely, a factor based on a single
observation of questionable quality, or one extrapolated from
another factor for a similar process, would probably be labeled D
or E. Several subjective schemes have been used in the past to
assign these ratings, depending upon data availability, source
characteristics, etc.
Because these ratings are subjective and take no account of
the inherent scatter among the data used to calculate factors,
they should be used only as approximations, to infer error bounds
or confidence intervals about each emission factor. At most, a
rating should be considered an indicator of the accuracy and
precision of a given factor used to estimate emissions from a
large number of sources. This indicator will largely reflect the
professional judgement of the authors and reviewers of AP-42
Sections concerning the reliability of any estimates derived with
these factors.
The rating scheme used in this report is summarized below.
A Developed from A-rated test data taken from many
randomly chosen facilities in the industry population.
B Developed only A-rated test data from a reasonable
number of facilities.
C Developed only from A- and B-rated test from a
reasonable number of facilities.
D Developed from only A- and B-rated test data from a
small number of facilities.
11
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E Developed from C- and D-rated test data and there may
be reason to suspect that the facilities tested do not
represent a random sample of the industry.
Most of the information available from AP-42 regarding
criteria pollutant emissions from iron foundries pertains to
particulate matter.
Appendices B, C, and D are the sources of the emission
factors presented in Table 2 and portions of Table 3, as
indicated. Appendix B, Toxic Air Pollutant Emission Factors for
Iron Foundries, gives emission factors for various foundry
furnaces under controlled and uncontrolled conditions. This
report uses the uncontrolled emissions factors, which have-been
expressed as units mg/Mg metal melted (tapped from furnace).
Appendix C, Criteria Air Pollutant Emission Factor for Gray
Iron Foundries, presents uncontrolled emissions of criteria
pollutants from various processes in iron foundries. The
criteria pollutants are total particulates, particulate matter
less than ten microns (PM,0), oxides of sulfur (SC^), oxides of
nitrogen (NC^), volatile organic compounds (VOC), carbon monoxide
(CO), and lead. Where applicable, emission factors are expressed
as mg/Mg metal melted, and presented in Table 2.
Appendix D, Threshold Limit Values and Biological Exposure
Indices for 1988-1989, presents substances common to foundry
processes and their effects on humans in the work environment.
This information serves to qualify the pollutant emission factors
in this report into human exposure terms, and explains their
effects on the human body.
Additional emission factors for criteria pollutants
(especially non-particulate pollutants) have been developed as
part of the National Acid Precipitation Assessment Program
(NAPAP). The major objective of NAPAP was to develop volatile
organic compound (VOC) emission factors for Source Classification
Codes (SCC) that had no emission factors in either AP-42 (4th
Edition) or AP-42, Supplement A. Also included in that work was
the development of nitrogen oxides (NOX) and sulfur dioxide (SCfe)
emission factor estimates for SCC's which were included in
reports submitted by States that previously lacked these factors.
The new emission factors that resulted from the NAPAP effort
are typically not of the same quality as those found in AP-42.
The NAPAP factors represent best estimates and were generated
from estimates taken from the literature, from averaging data
submitted by 13 State air quality offices, and through technology
transfer of emission factors for SCC's from similar industries.
The emission factors generated in the NAPAP work have been rated
E due to lack of rigorous quality assurance.
12
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The emission factors developed for the NAPAP emission
inventory normally represent uncontrolled emissions. For PM,0
emission factors, AP-42 should be consulted since the particulate
emission factors developed as part of the NAPAP effort were for
total suspended particulates (TSP), not PM,0.
Criteria air pollutant emission factors for foundry
processes are presented in Table 2. Those emission factors
derived from AP-422 represent a range of emissions, samples and
foundries under which testing was conducted. Those emission
factors derived from NAPAP were developed from States files,
published reports from both industrial and government sources,
AP-42, engineering estimates, and personal communication with
various industry representatives. In the instances where NAPAP
used AP-42 data, the AP-42 data range was averaged to present a
single value.
13
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TABLE 2. CRITERIA EMISSIONS, ng/Mg METAL MELTED
6.2 x 10C
6.2 x 10C
VOC 9 x 10
NOX 5 x 10*
CO
7.25 x 10'
7.25 x 10'
Electric Arc Furnace
5.8 x 106
5.7 x 106
9 x 10*
1.5 x 105
9.0 x 10*
2 x 10* -
3 x 105
9.5 x 106
5 X 10* -
1.9 X 105
Inoculation
1.6 x 10C
2.5 x 10-
a
Pouring
1.03 x 10C
2.5 x 10C
7 x 10*
5 x 10-
Greensand Shakeout
1.12 x 106
1.12 x 106
6x105
Neg
Notes/References
AP-422
NAPAP3
NAPAP3
AP-422
NAPAP-
AP-A2'
'NAPAP-
AP-A2'
SO 1.8x10-
Neg
1.25 x 10"
1.0 x 10
Neg
AP-42'
NAPAP-
Units are expressed as mg/Hg metal inoculated.
Neg = negligible
Dash = no data
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SECTION 4
TOXIC POLLUTANT EMISSION FACTORS
Iron foundries produce toxic pollutants from five major
processes. These processes include metal melting, mold and core
production, inoculation, pouring, and greensand shakeout.
Baldwin4'5 measured concentrations of toxic air emissions for
different foundry processes; from these concentration
measurements, sampling data, and site parameters, emission
factors have been calculated which give a breakdown of the
emissions from iron foundries.
The toxicity of a material and the extent to which that
material is present merits a corresponding "level of concern";
the primary level of concern is noted for different foundry
process. Emissions may be discharged both directly and
indirectly into the surrounding air. Toxic organic emissions are
presented in Table 3 for each of these processes. Toxic
inorganic emissions are presented in Table 4. Since magnesium
(abbreviated Mg) is a major toxic pollutant, and emission factors
are reported as mg/Mg (milligrams per megagram iron produced),
the element magnesium will be spelled out to avoid confusion.
METAL MELTING
Cupolas
Toxic emissions from cupolas include both organic and
inorganic materials, which may be emitted directly or indirectly.
Cupolas are the primary process of melting in foundries and also
produce the most toxic emissions. It is estimated that 68.8
percent of all the health risk from foundries is from foundries
with cupolas.6 The cupola organic emissions factors which are of
primary concern are:
o halogenated hydrocarbons 1.92 mg/Mg
o aromatic hydrocarbons 1.70 mg/Mg
o halogenated aromatics 1.70 mg/Mg
o silicones 0.43 mg/Mg
o heterocyclic N compounds 0.16 mg/Mg
o amines 0.14 mg/Mg
15
-------
TABLE 3. ORGANIC EMISSIONS, mg/Hg IRON PRODUCED
Aliphatic Hydrocarbons
Halogenated Hydrocarbons
Aromatic Hydrocarbons
Fused Aromatics
C>216 HU)
Halogenated Aromatics
.Heterocyclic N Compounds
Heterocyclic S Compounds
Alcohols
Phenols
Ketones
Amines
Si Iicones
Heterocyclic 0 Compounds
Nitroaromatics
Ethers
Aldehydes
Phosphates
Nltriles
Alkyl S Compounds
Sulfonic Acids
Sulfoxides
Amides
Carboxylic Acids
Esters
Haloaliphatics
Electric Arc
Furnaces a
4.94
4.94
3.41
3.41
0.12
0.12
0.40
0.12
0.84
0.40
0.37
1.63
0.00
0.02
0.00
0.82
0.00
0.12
0.12
0.12
0.12
0.4
0.12
Cupola8
1.92
1.92
1.70
1.70
0.16
0.16
0.14
0.14
1.51
0.14
0.43
1.01
0.11
1.10
0.11
0.16
0.11
0.14
0.14
0.14
0.14
0.14
0.89
Inoculation
0.08
0.08
0.19
0.05
0.01
0.01
0.01
0.06
0.01
0.01
0.18
0.00
0.05
0.01
0.01
0.00
0.01
0.01
0.01
0.01
0.01
0.01
0.02
Pouring"
0.78
0.78
0.56
0.56
0.14
0.14
0.26
0.05
0.42
0.31
0.07
0.47
0.03
0.2
0.03
0.06
0.03
0.08
0.06
0.05
0.09
0.26
0.22
Green Sand
Shakeoutb
0.39
1.34
1.34
0.13
0.56
0.05
0.31
0.31
0.05
0.31
0.05
0.01
0.05
0.05
0.01
0.03
0.03
0.23
0.25
0.15
0.12
"Baldwin
K 4
DBaldwin
NOTE: Emission factors for organic emissions from electric induction furnaces are not presently
available. 7
16
-------
TABLE 4. INORGANIC EMISSIONS, mg/Mg IRON PRODUCED*
Electric Arc
Element Cupola Furnace Inoculation Pouring
Ag 8.7 1.0
Al 55 >66
AS 26.1 7.3-26.8 0.1
B 81 56 57
Ba 55 65
Be 0.02 0.04
Bi 3.6 0.1
Ca 56 >66
Cd l,654a 1.5 0.8
Ce >66 3.1
Co 0.1 0.35
Cr 97 4.0 >66
Cs 0.7
CU 850° 11.7 14.7
EU 0.04
F 6,614a >66
Fe 55.8 >66
Ga 1.2 0.7
Ge 0.06
Hg 36 22 11
K 56 >66
La 9.4 2.6
Li 3.4
Magnesium 56 >66
Mn 125,000 65 35 >66
Mo 5.1 6.7
Na 56 >66
Nb 0.5
Nd 0.1
Ni 0.31 25
P 15 >66
Pb 5 x 104 - 323 56 11
5.5 X 10bC
2.6 X 105d
Pr o.i
Rb 9.4 0.2
S 56 >66
Sb 159 0.8
Sc 0.04 0.13
Se 5.8 0.1
Si 56 >66
Sm 0.2
Sn 18 1.0
Sr 72.5 4-0
17
-------
TABLE 4. (Continued)
Element
Cupola
Electric Arc
Furnace
Inoculation
Pouring
Te
Th
Ti
U
V
W
Y
Zn
Zr
1.5
56
56
0.7
56
29
0.
1.
>66
0.
>66
0.
0.
>66
4.
2
1
4
1
8
0
All emission factors are calculated from Baldwin 1982, except
as noted:
aN.D. Johnson
Toxic Air Pollution Emission Factors
c 2
AP-42 (source of data in AP-42 is Reference 8) .
Criteria Air Pollution Emission Factors for the 1985 NAPAP
Emission Inventory.
A blank value indicates only that no data is available in the
literature and does not mean that this element is not present.
A > indicates upper limit of measurement apparatus.
18
-------
Inorganic emission factors for cupolas could not be obtained
for most elements, however, the following emission factors are
available:
o Arsenic 26.1 mg/Mg
o Lead 5 x 104 - 5 .5 x 105 mg/Mg
o Manganese 1.25 x 105 mg/Mg
o Copper 8.5 x 102 mg/Mg
It is well known that toxic inorganics such as cadmium and
mercury are emitted during melting processes, notably the cupola,
if present in the raw materials charged into the furnace.
However, emissions data are incomplete, with the result that
these emission factors do not appear in this report.
Individual cupola emissions vary widely, depending on the
blast rate, blast temperature, melt rate, the coke to melt ratio
and raw material composition. Although emission factors are not
applicable to all cupolas because of this wide variation,
emissions data per specific cupola may be used to project future
emissions in the presence of process changes.
The impurities in raw materials may contribute to higher
emission factors for halogenated hydrocarbons in cupolas and
EAFs. High emission readings for chromium, lead and mercury are
probably related to scrap quality and cleanliness. Dirty, oily
and low quality metallic raw materials fed to the furnace charge
preparation process will result in more emissions from the
melting unit.
Emission reduction efforts include the use of bag houses,
wet scrubbers, and afterburners to reduce particulates, carbon
monoxide (CO) and VOCs in cupola off-gases. Fabric filters are
most effective in controlling cupola emissions, reducing
manganese emissions from 250,000 to 300 mg/Mg. High energy
scrubbers, impingement scrubbers and wet caps are used with less
favorable results.
Use of gas for heat and graphite for carbon may reduce
emissions due to coke, which contributes to organics and trace
inorganics.
Electric Arc Furnaces
EAFs are also sources of organics and inorganics which are
released both directly and indirectly. Uncontrolled, indirect
emissions have been observed at very high levels for both organic
and inorganic emissions.
19
-------
Organic emission factors which are of primary concern are:
o halogenated hydrocarbons 4.94 mg/Mg
o aromatic hydrocarbons 3.'41 mg/Mg
o halogenated aromatics 3.41 mg/Mg
o amines 0.40 mg/Mg
Inorganic emission factors for EAFs are:
o tin 1,654 mg/Mg
o antimony 3 mg/Mg
o silver 36 mg/Mg
o lead 323 mg/Mg
o mercury 35 mg/Mg
o boron 81 mg/Mg
o fluorine 6,614 mg/Mg
o chromium 97 mg/Mg
o manganese 65 mg/Mg
Of these emission factors, chromium and lead are of primary
concern.
Raw material quality control in this phase may help
eliminate these emissions. Although uncontrolled manganese
emissions from EAFs have been measured to be 75,000 mg/Mg. The
use of a fabric filter can reduce these emissions by 99 percent.9
Electric Induction Furnaces
Electric induction furnaces using clean steel scrap produce
particulate emissions comprised largely of iron oxides. High
emissions from clean charge materials are due to cold charges.
When contaminated charges are used, higher emission rates result.
According to Shaw1 , contamination on charge materials may
originate from:
o rust on pig iron and scrap;
o adhering dirt;
20
-------
o paint on scrap;
o various deposits on scrap, e.g. oil and fuel breakdown
products in internal combustion engine scrap, putty on scrap
window frames, grease and paint on machinery scrap and
engine parts;
o molding materials adhering to returns and foundry scrap
o carbon or graphite or other additions in powder form, or
other additions containing powder;
o cutting-oils on steel turnings and cast iron borings;
o zinc on galvanized scrap, or contained in zinc die castings
and,
o iron and steel scrap containing nonferrous alloys or
plating, e.g. bearing materials, brass inserts, soldered
joints.
Dust emissions from electric induction furnaces are
dependant upon the charge material composition, the melting
method (cold charge or continuous), the melting rate, and the
purity of the materials used.
The results available of measurements taken on furnaces
usinq clean scrap show a range of total dust emissions from 3.12
x 10 to 1.82 x 105 mg/Mg metal melted.10 Where contaminated
charges are used, much higher emission rates are found.
The highest emissions occur during a cold charge, (usually
the first charge of the day), in combination with a high
percentage of uncleaned steel scrap. The emissions presented in
Table 5 resulted from cold charge conditions using two-thirds
returns and one-third uncleaned steel, at a 3.6 kg/hour melting
rate, as measured by the CIATF Commission 4 Environmental
Control.
Oxidation of the exposed molten metal surface produces the
metallurgical smoke constituents in the table above. Molecular
weight conversion may be used to determine the elemental metal
content of the emissions.
21
-------
TABLE 5. INDUCTION FURNACE EMISSIONS
Malleable Iron
mg/Mg
SiC^
ZnO
A^q,
Cr2Q3
CaO
MnO
MoO
TiO
NiO
BA
PbO
SnCl,
B^ Ps
V2°5
CuO
CoO
BaO
6.5 x
5.2 x
2.6 x
1.3 x
6.5 x
1.3 x
2.6 x
1.3 x
1.3 x
2.6 x
1.3 x
2.6
2.6
7.8
1.3
2.6
2.6
104
104
104
103
102
103
102
102
102
101
101
10
Ductile Iron
mg/Mg
1.3 x
7.8 x
5.2 X
2.0 x
2.6 x
1.3 x
2.6 x
5.2
1.3 x
2.6
1.3 x
2.6
2.6
7.8
2.6
2.6
2.6
104
103
104
103
102
103
101
102
101
MOLD AND CORE PRODUCTION
In addition to organic binders, molds and core? may be held
together in the desired shape by means of a cross-linked organic
polymer network. This network (of polymers) undergoes thermal
decomposition when exposed to the very high temperatures of
22
-------
casting (typically 1400°C for iron castings). At these
temperatures it is likely that pyrolysis of the chemical binder
will produce a complex of free radicals which will recombine to
form a wide range of chemical compounds having widely differing
concentrations. In order to assess the environmental
implications of these thermal-decomposition products, it is
necessary to identify and quantify each of the compounds
liberated. Each of the chemical binder systems gives rise to a
number of different thermal-decomposition products, these
products being characteristic of the different binder system.11
There are many different types of resins currently in use
having diverse and toxic compositions. In spite of an intensive
literature search, there are no data currently available for
determining the toxic compounds in a particular resin which are
emitted to the atmosphere, and to what extent these emissions
occur. Toxic compounds are contained in resins and some are
presumably emitted to the atmosphere but at an undetermined rate.
Toxic compounds contained in resins may include:
o 4, 4' diphenylmethane diisocyanate
o kerosene
o polymethylene polyphenylene isocyanate
o catalytic reformer fractionator residue (petroleum
derivative)
o methylene bis(phenylisocyanate) (MBI)
o diethylene glycol
o nickel soaps of fatty acids
o hydrotreated light distillates (petroleum derivative)
o formaldehyde
o phenol
o ethyl-3-epoxypropionate
The mix of pollutants liberated during core and mold making
are a result of complex chemical reactions which are directly
related to the quantity and composition chemicals present in the
uncured resin.11 Some foundry atmosphere contaminants commonly
encountered during mold and core making are given in Table 6.
23
-------
TABLE 6.
PROCESS
Shell
SOME FOUNDRY-ATMOSPHERE CONTAMINANTS EVOLVED DURING MOLD AND CORE MAKING, CASTING, AND COOLING
11
Hot-box
BINDER INGREDIENTS
Ammonia
Phenol
Hexamethylene tetramine
Stearates
Fatty acids
Formaldehyde
Phenol
Urea
Furfuryl alcohol
POTENTIAL EMISSIONS
Ammonia
Aromatic hydrocarbons (benzene, toluene, xylene, etc.)
Phenol and homologues (phenol, cresol, xylenol, etc.)
Hexamethylene tetramine
Other amines (e.g. trimethylamine)
Hydrogen cyanide
Aromatic hydrocarbons
Phenol and homologues
Ammonia
Chlorinated hydrocarbons
Hydrogen cyanide
to
Cold-set
Formaldehyde
Furfuryl alcohol
Phenol
Benzene )
Toluene ) depends on catalyst
Xylene )
Sulphur dioxide
Hydrogen sulphide
Mercaptans (e.g. methyl, ethyl mercaptan)
Aromatic hydrocarbons
Phenol and homologues
Furan and homologues (furan, methyl furan, etc.)
Carbonyl sulphide
Carbon disulphide
Aromatic sulphur compounds
( Methyl ethyl ketone
( Acetone - from S02 - gassed system only)
Cold-box
(amine-gassed)
Carbon dioxide
Triethyl amine
Dimethyl ethyl amine
MDI
Phenol
Resin solvents (e.g. trimethyl
benzene, isophorone)
Naphthalene and homologues
Hydrogen cyanide
Phenol and homologues
Aromatic hydrocarbons
Aniline and homologues (aniline, toluidine, etc.)
Aliphatic amines
Resin solvents (e.g. trimethyl benzene, isophorone)
Isocyanates (e.g. methyl, phenyl isocyanate)
Benzoquinolines
-------
INOCULATION
Particulates, arsenic, chromium, halogenated hydrocarbons,
and aromatic hydrocarbons are released in the inoculation
process.
Inorganic emission factors pertaining to inoculation have
been calculated for most elements. Those which are of primary
concern are:
o boron 56 mg/Mg
o vanadium 56 mg/Mg
o chromium 4 mg/Mg
o arsenic 7.3 - 26.8 mg/Mg
o lead 56 mg/Mg
Emission factors have been calculated for organics released
in the inoculation process. Emission factors for halogenated
hydrocarbons, 0.08 mg/Mg, and halogenated aromatics, 0.05 mg/Mg,
are of primary importance.
POURING
The pouring (and cooling) process takes place after melting
and inoculation. Emissions are related to mold size, mold
composition, sand to metal ratio, pouring temperature and pouring
rate. Organic compounds in the emissions due to the presence of
sea coal and chemical binders in the sand are evolved into the
surrounding environment during the pouring process. During this
process, PM,0 emission factors ranged from 2.5 x 103 to 4.2 x 106
mg/Mg (see Table 2).
Emissions during pouring include decomposition products of
resins (CO, carbon dioxide (COj), phenols, hydrogen cyanide,
ammonia, benzo(a)pyrene), other organic compounds, and
particulate matter.
Emission factors have been calculated for inorganics evolved
during the pouring process. The emission factor for nickel has
been calculated at 25.3 mg/Mg, and for lead at 11.3 mg/Mg.
Emission factors for boron, 11 mg/Mg and chromium, 66 mg/Mg were
of primary concern.
Emission rates were measured for aliphatic hydrocarbons,
halogenated hydrocarbons, aromatic hydrocarbons, fused aromatics,
halogenated aromatics, heterocyclic N compounds, heterocyclic S
compounds, alcohols, phenols, ketones, amines, silicones,
25
-------
heterocyclic 0 compounds, nitroaromatics, ethers, aldehydes,
phosphates, nitriles, alkyl S compounds, sulfonic acids,
sulfoxides, amides, carboxylic acids, and esters. The emission
factors for these compounds are presented in Table 6.
Polynuclear aromatic organics (PNA) and fused aromatic
organics are significant because these emissions may be present
during cooling processes, where they can be formed and released,
rather than in the pouring process. At present there are no
emissions measurements for PNAs.
GREENSAND SHAKEOUT
The removal of castings from a sand mold releases moisture
that has been trapped in the mold, dust from the sand and binders
which have dried during pouring, and products of thermal
decomposition of the chemical binders as they are4 exposed to air.
Available emissions test data range from 8.5 x 10 mg/Mg to 9 x
10 mg/Mg of iron castings with an average of about 1.5 x 10
mg/Mg of iron castings. The data indicate a wide variation in
the emission rate.4
As reported by Baldwin4 the experiments of Bates and Scott12
showed higher peak hydrocarbon concentrations (1500 ppm) during
shakeout than during pouring and cooling, although the average
concentrations were lower during shakeout. The particulate
emissions during these laboratory tests were 55 percent higher
with a 10 fold particle count increase over those of pouring.
Toeniskoetter and Schafer13 sampled many foundries for selected
emissions from different binder systems. Their results show that
the isocyanate concentration is frequently greater at shakeout
than at the pouring station.
AIR TOXIC EMISSION FACTOR RATING
The emission factors presented in this report originated
from diverse sources, and therefore have variable reliability
(see Section 3 for rating scheme used in this report). The
emission factors are rated according to source.
o All emission factors from Criteria Air Pollutant Emission
Factors, prepared for the 1985 NAPAP Emissions Inventory,
October 1988, are rated E.
o All emission factors calculated from the work by Baldwin,
1980; and Baldwin, 1982; are rated D.
o The emission factors from AP-42 for
o VOC, NCy, CO, and SC^ are rated B for all sources
26
-------
o PM^ from cupolas are rated C
o PM,0 from pouring are rated D
o PM,0 from EAF and Greensand Shakeout are rated E
27
-------
REFERENCES
1. Air Pollution Aspects of the Iron Foundry Industry. APTD-
0806 (NTIS PB 2 04 712), U.S. Environmental Protection
Agency, NC, 1971.
2. Compilation of Air Pollutant Emissions Factors, AP-42, (NTIS
PB89-128631), Supplement B, Volume I, Fourth Edition. U.S.
Environmental Protection Agency, 1988.
3. Stockton, M.B., and J.H.E. Stelling. Criteria Pollutant
Emission Factors for the 1985 NAPAP Emissions Inventory.
EPA-600/7-87-015 (NTIS PB87-198735), U.S. Environmental
Protection Agency, 1987.
4. Baldwin, V.H. Jr. Environmental Assessment of Iron Casting.
EPA-600/2-80-021 (NTIS PB8Q-187545), U.S. Environmental
Protection Agency, 1980.
5. Baldwin, V.H. Environmental Assessment of Melting,
Inoculation, and Pouring. American Foundrymen's Society.
153:65-72, 1982.
6. Temple Barker and Sloane, Inc. integrated Environmental
Management Foundry Industry Study, Technical Advisory Panel.
Presentation to the U.S. Environmental Protection Agency,
April 4, 1984.
7. Johnson, N.D. Consolidation of Available Emission Factors
for Selected Toxic Air Pollutants. ORTECH International,
1988.
8. Jeffrey, J-, J. Fitzgerald, and P- Wolf. Gray Iron Foundry
Industry Particulate Emissions: Source Category Report.
EPA-600/7-86-054 (NTIS PB87-145702), U.S. Environmental
Protection Agency, 1986.
9. Pope, A.A., P.A. Cruse, and C.C. Most. Toxic Air Pollutant
Emission Factors - A Compilation for Selected Air Toxic
Compounds and Sources. EPA-450/2-88-006a (NTIS PB89-
135644), U.S. Environmental Protection Agency, 1988.
10. Shaw, F.M. CIATF Commission 4 Environmental Control:
Induction Furnace Emission. Commissioned by F.M. Shaw,
British Cast Iron Research Association, Fifth Report. Cast
Metals Journal 6:10-28, 1982.
11. Ambidge, P.F. and P.D.E. Biggins. Environmental Problems
Arising From the Use of Chemicals in Moulding Materials.
BCIRA Report, 1984.
28
-------
12. Bates, C.E., and W.D. Scott. The Decomposition of Resin
Binders and the Relationship Between Gases Formed and the
Casting Surface Quality. Part 2 - Gray Iron. American
Foundrymen's Society, Des Plains, Illinois, 1976. pp. 793
804.
13. Toeniskoetter, R.H., and R.J. Schafer. Industrial Hygiene
Aspects of the Use of Sand Binders and Additives. BCIRA
Report 1264, 1977.
14. Threshold Limit Values and Biological Exposure Indices for
1989-1990. In: Proceedings of American Conference of
Governmental Industrial Hygienists, Ohio, 1989.
UNCITED REFERENCES
1. AIRS Facility Subsystem. Source Classification Codes and
Emission Factor Listing for Criteria Air Pollutants. EPA-
450/4-90-003, U.S. Environmental Protection Agency, 1990.
2. ACGIH. Particle-Size-Selective Sampling in the Workplace
Cincinnati, OH, 1984. pp. 80.
29
-------
APPENDIX A
AP-42 Section on Gray Iron Foundries
AP-42 Section
7.10 Gray Iron Foundries A-2
A-l
-------
(copied from Compilation of Air Pollutant Emission Factors,
Ap-42 Supplement B, Volume 1, Fourth Edition
U.S. Environmental Protection Agency, 1988)
7.10 GRAY IRON FOUNDRIES
7.10.1 General1-5
Gray iron foundries produce gray iron castings from scrap iron, pig iron
and foundry returns by melting, alloying and molding. The production of gray
iron castings involves a number of integrated steps, which are outlined in
Figures 7.10-1 and 7.10-2. The four major production steps are raw materials
handling and preparation, metal melting, mold and core production, and casting
and finishing.
Raw Materials Handling And Preparation - Handling operations include re-
ceiving, unloading, storing and conveying of all raw materials for both furnace
charging and mold and core preparation. The major groups of raw materials re-
quired for furnace charging are metallics, fluxes and fuels. Metallic raw
materials include pig iron, iron and steel scrap, foundry returns and metal
turnings. Fluxes include carbonates (limestone, dolomite), fluoride (fluor-
spar), and carbide compounds (calcium carbide).^ Fuels include coal, oil,
natural gas and coke. Coal, oil and natural gas are used to fire reverberatory
furnaces. Coke, a derivative of coal, is used as a fuel in cupola furnaces.
Carbon electrodes are required for electric arc furnaces.
As shown in Figures 7.10-1 and 7.10-2, the raw materials, raetallics and
fluxes are added to the melting furnaces directly. For electric induction
furnaces, however, the scrap metal added to the furnace charge must first be
pretreated to remove any grease and/or oil, which can cause explosions. Scrap
metals may be degreased with solvents, by centrifugation, or by preheating to
combust the organics.
In addition to the raw materials used to produce the molten metal, a
variety of materials is needed to prepare the sand cores and molds that form
the iron castings. Virgin sand, recycled sand and chemical additives are
combined in a sand handling system typically comprising receiving areas, con-
veyors, storage silos and bins, mixers (sand mullets), core and mold making
machines, shakeout grates, sand cleaners, and sand screening.
Raw materials are received in ships, railroad cars, trucks and containers,
then transferred by truck, loaders and conveyors to both open piles and enclosed
storage areas. When needed, the raw materials are transferred from storage to
process areas by similar means.
Metal Melting - The furnace charge includes metallics, fluxes and fuels.
The composition of the charge depends upon the specific metal characteristics
required. Table 7.10-1 lists the different chemical compositions of typical
irons produced. The three most common furnaces used in the gray iron foundry
industry are cupolas, electric arc, and electric induction furnaces.
The cupola, which is the major type of furnace used in industry today, is
typically a" vertical cylindrical steel shell with either a refractory lined or
water cooled inner wall. Refractory linings usually consist of silica brick,
or dolomite or magnesium brick. Water cooled linings, which involve circulating
10/86 Metallurgical Industry 7.10-1
A-2
-------
o
O
z
3
o
CO
futcHoted
Scrap
, ,
Melodies 1 1
Fluxet
S"nL. I
1
Pf
^
i r*"
*
Cupolo
Induction
lUverbtrolcxy
Ductile
Iron |
|
e»
Ollxi
-^
ond
Cooling
furnace Chotg« ficpoiatlon
Melting aitd Coiling
Slag
J
Scion
R*
So
A«,allon/ 1
"* * Cooling |
lutn
nd
Sand 1
r ~
1
to
Sand
Blndert
Mixer
Muller
Soiid
Ditcardi
Good
Scrap
Mela)
Cleaning and Finltliing
T
Pollern«
Core ond
Mold Pieparalion
O
00
Figure 7.10-1. Typical iron foundry diagram.
-------
MCTALllCf
o
00
n
t
s
CD
rt
SAND
PREPARATION
FINISHING
Er'DUSI
CAS AND
FAITICUIAII
{MISSIONS
DUCTILE IRON
INNOCULATION
COOLING AND
CLEANING
Figure 7.10-2. Emission points in a typical iron foundry
2-3
o
u>
-------
TABLE 7.10-1.
CHEMICAL COMPOSITION OF FERROUS CASTINGS
BY PERCENTAGE
Element
Gray iron
Malleable iron
(as white iron)
Ductile iron3
Steel
Carbon
Silicon
Manganese
Sulfur
Phosphorus
2.5 -
1.0 -
0.40 -
0.05 -
0.05 -
4
3
1
0
1
.0
.0
.0
.25
.0
1.8
0.5
0.25
0.06
0.06
- 3
- 1
- 0
- 0
- 0
.6
.9
.80
.20
.18
3.0 - 4.0
1.4 - 2.0
0.5 - 0.8
<0.12
<0.15
<2
0.2
0.5
<0
<0
.Ob
- 0
- 1
.06
.05
.8
.0
^Necessary chemistry also includes 0.01 - 1.0% Mg.
bSteels are further classified by carbon content: low carbon, <0.20%;
medium carbon, 0.20 - 0.50%; high carbon, >0.50%.
water around the outer steel shell, are used to protect the furnace wall from
interior temperatures. The cupola is charged at the top with alternate layers
of coke, metallics and fluxes.2 The cupola is the only furnace type to use
coke as a fuel; combustion air used to burn the coke is introduced through
tuyeres located at the base of the cupola. 2 Cupolas use either cold blast air,
air introduced at ambient temperature, or hot blast air with a regenerative
system which utilizes heat from the cupola exhaust gases to preheat the com-
bustion air.^ Iron is melted by the burning coke and flows down the cupola.
As the melt proceeds, new charges are added at the top. The flux removes non-
metallic impurities in the iron to form slag. Both the molten iron and the slag
are removed through tap holes at the bottom of the cupola. Periodically, the
heat period is completed, and the bottom of the cupola is opened to remove the
remaining unburned material. Cupola capacities range from 1.0 to 27 megagrams
per hour (1 to 30 tons per hour), with a few larger units approaching 90 mega-
grams per hour (100 tons per hour). Larger furnaces operate continuously and
are inspected and cleaned at the end of each week or melting cycle.
Electric arc furnaces (EAF) are large, welded steel cylindrical vessels
equipped with a removable roof through which three retractable carbon electrodes
are Inserted. The electrodes are lowered through the roof of the furnace and
are energized by three phase alternating current, creating arcs that melt the
metallic charge with their heat. Additional heat is produced by the resistance
of the metal between the arc paths. The most common method of charging an
electric arc furnace is by removing the roof and introducing the raw materials
directly. Alternative methods include introducing the charge through a chute
cut in the roof or through a side charging door in the furnace shell . Once
the melting cycle is complete, the carbon electrodes are raised, and the roof
is removed. The vessel is tilted, and the molten iron is poured into a ladle.
Electric arc furnace capacities range from 0.23 to 59 megagrams (0.25 to 65
tons). Nine to 11 pounds of electrode are consumed per ton of metal melted.
7.10-4
EMISSION FACTORS
A-5
10/86
-------
Electric induction furnaces are either cylindrical or cup shaped refractory
lined vessels that are surrounded by electrical coils which, when energized with
high frequency alternating current, produce a fluctuating electromagnetic field
to heat the metal charge. For safety reasons, the scrap metal added to the
furnace charge is cleaned and heated before being introduced into the furnace.
Any oil or moisture on the scrap could cause an explosion in the furnace.
Induction furnaces are kept closed except when charging, skimming and tapping.
The molten metal is tapped by tilting and pouring through a hole in the side of
the vessel. Induction furnaces also may be used for metal refining in conjunc-
tion with melting in other furnaces and for holding and superheating the molten
metal before pouring (casting).
The basic melting process operations are 1) furnace charging, in which
metal, scrap, alloys, carbon, and flux are added to the furnace; 2) melting,
during which the furnace remains closed; 3) backcharging, which involves the
addition of more metal and alloys, as needed; 4) refining and treating, during
which the chemical composition is adjusted to meet product specifications; 5)
slag removing; and 6) tapping molten metal into a ladle or directly into molds.
Mold And Core Production - Molds are forms used to shape the exterior of
castings. Cores are molded sand shapes used to make the internal voids in cast-
ings. Cores are made by mixing sand with organic binders, molding the sand into
a core, and baking the core in an oven. Molds are prepared of a mixture of wet
sand, clay and organic additives to make the mold shapes, which are usually
dried with hot air. Cold setting binders are being used more frequently in both
core and mold production. The green sand mold, the most common type, uses
moist sand mixed with 4 to 6 percent clay (bentonite) for bonding. The mixture
is 4 to 5 percent water content. Added to the mixture, to prevent casting
defects from sand expansion when the hot metal is poured, is about 5 percent
organic material, such as sea coal (a pulverized high volatility bituminous
coal), wood flour, oat hulls, pitch or similar organic matter.
Common types of gray iron cores are:
- Oil core, with typical sand binder percents of 1.0 core oil, 1.0 cereal,
and-0 to 1 pitch or resin. Cured by oven baking at 205 to 315°C (400 to
600°F), for 1 to 2 hours.
- Shell core, with sand binder typically 3 to 5 percent phenolic and/or
urea formaldehyde, with hexamine activator. Cured as a thin layer on a
heated metal pattern at 205 to 315°C (400 to 600°F), for 1 to 3 minutes.
- Hot box core, with sand binder typically 3 to 5 percent furan resin, with
phosphoric acid activator. Cured as a solid core in a heated metal pat-
tern at 205 to 315°C (400 to 600°F), for 0.5 to 1.5 minutes.
- Cold set core, with typical sand binder percents of 3 to 5 furan resin,
with phosphoric acid activator; or 1 to 2 core oil, with phosphoric acid
activator. Hardens in the core box. Cured for 0.5 to 3 hours.
- Cold box core, with sand binder typically 1 to 3 percent of each of two
resins, activated by a nitrogen diluted gas. Hardens when the green core
is gassed in the box with polyisocyanate in air. Cured for 10 to 30
seconds.
10/86 Metallurgical Industry 7.10-5
A-6
-------
Used sand from castings shakeout is recycled to the sand preparation area
and cleaned to remove any clay or carbonaceous buildup. The sand is then
screened and reused to make new molds. Because of process losses and discard
of a certain amount of sand because of contamination, makeup sand is added.
Casting And Finishing - After the melting process, molten metal is tapped
from the furnace. Molten iron produced in cupolas is tapped from the bottom of
the furnace into a trough, thence into a ladle. Iron produced in electric arc
and induction furnaces is poured directly into a ladle by tilting the furnace.
At this point, the molten iron may be treated with magnesium to produce ductile
iron. The magnesium reacts with the molten iron to nodularize the carbon in
the molten metal, giving the iron less brittleness. At times, the molten metal
may be inoculated with graphite to adjust carbon content. The treated molten
iron is then ladled into molds and transported to a cooling area, where it
solidifies in the mold and is allowed to cool further before separation (shake-
out) from the mold and core sand. In larger, more mechanized foundries, the
molds are conveyed automatically through a cooling tunnel. In simpler found-
ries, molds are placed on an open floor space, and the molten iron is poured
into the molds and allowed to cool partially. Then the molds are placed on a
vibrating grid to shake the mold and core sand loose from the casting. In the
simpler foundries, molds, core sand and castings are separated manually, and
the sand from the mold and core is then returned to the sand handling area.
When castings have cooled, any unwanted appendages, such as spurs, gates,
and risers, are removed. These appendages are removed with oxygen torch,
abrasive band saw, or friction cutting tools. Hand hammers may be used, in
less mechanized foundries, to knock the appendages off. After this, the cast-
ings are subjected to abrasive blast cleaning and/or tumbling to remove any
remaining mold sand or scale.
Another step in the metal melting process involves removing the slag in the
furnace through a tapping hole or door. Since the slag is lighter than molten
iron, it remains atop the molten iron and can be raked or poured out of cupola
furnaces through the slag hole located above the level of the molten iron.
Electric arc and induction furnaces are tilted backwards, and their slag is
removed through a slag door.
7.10.2 Emissions And Controls
Emissions from the raw materials handling operations are fugitive particu-
late generated from the receiving, unloading, storage and conveying of raw mate-
rials. These emissions are controlled by enclosing the major emission points
(e. g., conveyor belt transfer points) and routing air from the enclosures
through fabric filters or wet collectors. Figure 7.10-2 shows emission points
and types of emissions from a typical foundry.
Scrap preparation with heat will emit smoke, organic compounds and carbon
monoxide, and scrap preparation with solvent degreasers will emit organics.
Catalytic incinerators and afterburners can control about 95 percent of organic
and carbon monoxide emissions. (See Section 4.6, Solvent Degreasing.)
Emissions released from the melting furnaces include particulate matter,
carbon monoxide, organic compounds, sulfur dioxide, nitrogen oxides and small
quantities of chloride and fluoride compounds. The particulates, chlorides and
7.10-6 EMISSION FACTORS 10/86
A-7
-------
fluorides are generated from incomplete combustion of coke, carbon additives,
flux additions, and dirt and scale on the scrap charge. Organic material on
the scrap, the consumption of coke in the furnace, and the furnace temperature
all affect the amount of carbon monoxide generated. Sulfur dioxide emissions,
characteristic of cupola furnaces, are attributable to sulfur in the coke.
Fine particulate fumes emitted from the melting furnaces come from the
condensation of volatilized metal and metal oxides.
During melting in an electric arc furnace, particulate emissions are gen-
erated by the vaporization of iron and the transformation of mineral additives.
These emissions occur as metallic and mineral oxides. Carbon monoxide emissions
come from the combustion of the graphite lost from the electrodes and the carbon
added to the charge. Hydrocarbons may come from vaporization and partial
combustion of any oil remaining on the scrap iron added to the furnace charge.
The highest concentrations of furnace emissions occur during charging,
backcharging, alloying, slag removal, and tapping operations, because furnace
lids and doors are opened. Generally, these emissions escape into the furnace
building or are collected and vented through roof openings. Emission controls
for melting and refining operations usually involve venting the furnace gases
and fumes directly to a control device. Controls for fugitive furnace
emissions include canopy hoods or special hoods near the furnace doors and
tapping hoods to capture emissions and route them to emission control systems.
High energy scrubbers and baghouses (fabric filters) are used to control
particulate emissions from cupolas and electric arc furnaces in this country.
When properly designed and maintained, these control devices can achieve respec-
tive efficiencies of 95 and 98 percent. A cupola with such controls typically
has an afterburner with up to 95 percent efficiency, located in the furnace
stack, to oxidize carbon monoxide and to burn organic fumes, tars and oils.
Reducing these contaminants protects the particulate control device from poss-
ible plugging and explosion. Because induction furnaces emit negligible amounts
of hydrocarbon and carbon monoxide emissions, and relatively little particulate,
they are usually uncontrolled.2
The major pollutant emitted in mold and core production operations is par-
ticulate from sand reclaiming, sand preparation, sand mixing with binders and
additives, and mold and core forming. Organics, carbon monoxide and particulate
are emitted from core baking, and organic emissions from mold drying. Baghouses
and high energy scrubbers generally are used to control particulate from mold
and core production. Afterburners and catalytic incinerators can be used to
control organics and carbon monoxide emissions.
Particulate emissions are generated during the treatment and inoculation
of molten iron before pouring. For example, during the addition of magnesium
to molten metal to produce ductile iron, the reaction between the magnesium and
molten iron is very violent, accompanied by emissions of magnesium oxides and
metallic fumes. Emissions from pouring consist of hot metal fumes, and carbon
monoxide, organic compounds and particulate evolved from the mold and core
materials contacting the molten iron. Emissions from pouring normally are
captured by a collection system and vented, either controlled or uncontrolled,
to the atmosphere. Emissions continue as the molds cool. A significant quan-
tity of particulate is also generated during the casting shakeout operation.
These fugitive emissions must be captured, and they usually are controlled by
10/86 Metallurgical Industry 7.10-7
A-8
-------
either high energy scrubbers or bag filters.
Finishing operations emit large, coarse particles during the removal of
burrs, risers and gates, and during shot blast cleaning. These emissions are
easily controlled by cyclones and baghouses.
Emission factors for total particulate from gray iron furnaces are pre-
sented in Table 7.10-2, and emission factors for gaseous and lead pollutants
are given in Table 7.10-3. Tables 7.10-4 and 7.10-5, respectively, give factors
for ancillary process operations and fugitive sources and for specific particle
sizes. Particle size factors and distributions are presented also in Figures
7.10-3 through 7.10-8.
TABLE 7.10-2. EMISSION FACTORS FOR GRAY IRON FURNACES3
Process
Cupola
Electric arc furnace
Electric induction
furnace
Reverberatory
Control
device
Uncontrolled*3
Scrubber0
Venturi scrubber**
Electrostatic
precipitator6
Baghouse^
Single wet capS
Impingement scrubberS
High energy scrubberS
Uncontrolled*1
BaghouseJ
Uncontrolledk
Baghouse
Uncontrolled11
Baghouse111
Total Emission
particulate Factor
Rating
kg/Mg Ib/ton
6.9
1.6
1.5
0.7
0.3
4.0
2.5
0.4
6.3
0.2
0.5
0.1
1.1
0.1
13.8
3.1
3.0
1.4
0.7
8.0
5.0
0.8
12.7
0.4
0.9
0.2
2.1
0.2
C
C
C
E
C
B
B
B
C
C
D
E
D
E
Expressed as weight of pollutant/weight of gray iron produced.
bReferences 1,7,9-10.
References 12,15. Includes averages for wet cap and other scrubber types not
already listed.
References 12,17,19.
References 8,11.
References 12-14.
^References 8,11,29-30.
References 1,6,23.
^References 6,23-24.
^References 1,12. For metal melting only.
"Reference 4.
Reference 1.
7.10-8
EMISSION FACTORS
10/86
A-9
-------
o
vo
TABLE 7.10-3. GASEOUS AND LEAD EMISSION FACTORS FOR GRAY IRON FOUNDRIES
EMISSION FACTOR RATING: B
Furnace
type
Cupola
Uncontrolled
High energy
scrubber
Electric arcc
Electric
induction^
Reverberatory
Carbon monoxide Sulfur
kg/Mg Ib/ton kg/Mg
73C 1A5C 0.6Sd
0.3Sd
0.5-19 1-37 Neg
Neg Neg Neg
Volatile organic
dioxide Nitrogen oxides compounds Leadb
Ib/ton kg/Mg Ib/ton kg/Mg Ib/ton kg/Mg Ib/ton
l.2Sd - 0.05-0.6 0.1-1.1
0.6Sd - - -
Neg 0.02-0.3 0.04-0.6 0.03-0.15 0.06-0.3
Neg - - - - 0.005-0.05 0.009-0.1
----- 0.006-0.07 0.012-0.14
in
en
H
§
'Expressed as weight of pollutant/weight of gray iron produced.Dash no data.Neg = negligible.
bReferences 11,31,34.
cReference 2.
^Reference 4. S - Z sulfur in the coke. Assumes 30X of sulfur is converted to SO-.
eReference 4,6.
fReferences 8,11,29-30.
o
CD
-------
TABLE 7.10-4. PARTICULATE EMISSION FACTORS FOR ANCILLARY PROCESS OPERATIONS
AND FUGITIVE SOURCES AT GRAY IRON FOUNDRIES
t>
I
w
CO
in
O
H
O
Process
Scrap and charge
handling, heatlngb
Magnesium treatment0
Inoculation''
Pouring, cooling6
Shakeoutf
Cleaning, finishing*5
Sand handling^
Core making, baking b
Total Emitted to
Control emission factor work environment
kg/Mg Ib/ton kg/Mg Ib/ton
metal metal metal metal
Uncontrolled 0.3 0.6 0.25 0.5
Uncontrolled 0.9 1.8 0.9 1.8
Uncontrolled 1.5 - 2.5 3 - 5
Uncontrolled 2.1 4.2
Uncontrolledc 1.6 3.2
Uncontrolled 8.5 17 0.15 0.3
Uncontrolledc 1.8 3.6
Scrubber" 0.023 0.046
BaghouseJ 0.10 0.20
Uncontrolled 0.6 1.1 0.6 1.1
Emitted to
atmosphere Emission
Factor
kg/Mg Ib/ton Rating
metal metal
0.1 0.2 D
0.2 0.4 E
- - D
D
D
0.05 0.1 D
- - E
D
D
0.6 1.1 D
^Expressed as weight of pollutant/weight of gray Iron produced, except as noted. Daeh - no data.
^Reference 4.
cReferences 1,4.
^Reference 35-
References 1,3,25.
fReference 1.
8Kg of sand/Mg of sand handled.
"References 12,27.
jReference 12.
O
OO
-------
o
00
TABLE 7.10-5. PARTICLE SIZE DISTRIBUTION DATA AND EMISSION FACTORS
FOR GRAY IRON FOUNDRIES3
Emission Particle
Source Factor size
Rating (urn)
Cupola Furnace'5
Uncontrolled C 0.5
1.0
2.0
2.5
5.0
10.0
15.0
Controlled by baghouse E 0.5
1.0
2.0
2.5
5.0
10.0
15.0
Controlled by venturi
scrubber0 C 0.5
1.0
2.0
2.5
5.0
10.0
15.0
Cumulative mass 7.
< stated sizeb
44.3
69.1
79.6
84.0
90.1
90.1
90.6
100.0
83.4
91.5
94.2
94.9
94.9
94.9
95.0
100.0
56.0
70.2
77.4
77.7
77.7
77.7
77.7
100.0
Cumulative mass
kg/Mg metal
3.1
4.8
5.5
5.8
6.2
6.2
6.3
6.9
0.33
0.37
0.38
0.38
0.38
0.38
0.38
0.4
0.84
1.05
1.16
1.17
1.17
1.17
1.17
1.5
emission factor
Ib/ton metal
6.1
9.5
11.0
11.6
12.4
12.4
12.5
13.8
0.58
0.64
0.66
0.66
0.66
0.66
0.67
0.7
1.7
2.1
2.3
2.3
2.3
2.3
2.3
3.0
K
rt
P>
M
M
C
0.
(0
O
-------
TABLE 7.10-5 (cont.).
Process
Electric arc furnaced
Uncontrolled
Pouring, cooling^
Uncontrolled
Shakeoutb
Uncontrolled
Particle
size
(urn)
1.0
2.0
5.0
10.0
15.0
0.5
1.0
2.0
2.5
5.0
10.0
15.0
0.5
1.0
2.0
2.5
5.0
10.0
15.0
Cumulative mass %
< stated sizeb
13.0
57.5
82.0
90.0
93.5
100.0
d
19.0
20.0
24.0
34.0
49.0
72.0
100.0
23.0
37.0
41.0
42.0
44.0
70.0
99.9
100.0
Cumulative mass
kg/Mg metal
0.8
3.7
5.2
5.8
6.0
6.4
-
0.40
0.42
0.50
0.71
1.03
1.51
2.1
0.37
0.59
0.66
0.67
0.70
1.12
1.60
1.60
Emission
emission factor Factor
Ib/ton metal Rating
1.6 E
7.3
10.4
11.4
11.9
12.7
D
0.80
0.84
1.00
1.43
2.06
3.02
4.2
0.74 E
1.18
1.31
1.34
1.41
2.24
3.20
3.20
o
»I
K)
I
I1
LO
CO
CO
M
O
25
O
H
I
00
o.
aExpressed as weight of pollutant/weight of metal melted (produced). Dash = no data. Mass emission
rate data available in Tables 7.10-2 and 7.10-4 to calculate size specific emission factors.
bReferences 13,21-22,25-26. See Figures 7.10-3 through 7.10-8.
cPressure drop across venturi: approx. 102 inches of water.
^Reference 3, Exhibit VI-15. Averaged from data on two foundries. Because original test data could
not be obtained, Emission Factor Rating is E.
-------
H-
Z
UJ
o
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h-
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99.990
99.950
99.90
99.80
99.50
99.
98.
95.
90.
80.
70.
60.
50.
40.
30.
20.
10.
5.
2.
I.
0.5
0.2
0.15
O.I
0.0
TOTAL PARTI CUL ATE
EMISSION RATE
_ 69 Kg PARTICULATE
Mg METAL
MELTED (PRODUCED)
i.2
5.9
5.5
4.8
3.1
M
to
O
cn
or
a.
d
UJ
2
u
UJ
10'
PARTICLE DIAMETER, micrometers
Figure 7.10-3. Particle size distribution for uncontrolled cupola.21-22
10/86
Metallurgical Industry
A-14
7.10-13
-------
99.950
99.90
99.80
99.50
99.
98.
95.
90.
^_
z
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o
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UJ
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uj 50,
- 40.
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1.
0.5
0.2
0.15
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TOTAL PARTI CULATE A ^ kg PARTI CUL ATE
EMISSION RATE U'* Mg META|_
MELTED (PRODUCED)
^^^^"^
y£>
^^r
Gj
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P*
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-
-
-
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0.36 <
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0.32 V
UJ
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UJ
5
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U
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10
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10° I01 I02
PARTICLE DIAMETER, micrometers
Figure 7.10-4. Particle size distribution for
baghouse controlled cupola.*3
7.10-14
EMISSION FACTORS
A-15
10/86
-------
99.950
99.90
99.80
99.50
99.
98.
95..
90.
i-
LJJ 80.
0
5 70.
a 60.
uj 50.
P 40.
< 30,
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1 20.
j«
iii
tAJ
^
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2
3
U
_l
^
UJ
2
o>
2
10"' 10° 10 ' I02
PARTICLE DIAMETER, micrometers
Figure 7.10-5. Particle size distribution for venturi scrubber
controlled cupola.21-22
10/86
Metallurgical Industry
A-16
7.10-15
-------
Z
UJ
u
cr
u
>
H
<
99.990
99.950
99.90
99.80
99.50
99
98
95
90
80
70
60
50
40
30
20
10
5
2
I
0.5
0.2
0.15
O.I
0.0
10"
TOTAL PARTICULATE= 6.4
I EMISSION RATE
kg PARTICIPATE
Mg METAL
MELTED (PRODUCED)
i i i i i
5.9
5.7
5.2
3.6
0.8
IOW 10' 10'
PARTICLE DIAMETER, micrometers
UJ
V)
V)
V
UJ
o
P
X
<
a.
UJ
>
UJ
2
Figure 7.10-6. Particle size distribution for uncontrolled
electric arc furnace.3
7.10-16
EMISSION FACTORS
A-17
10/86
-------
99.99O
99.950
99.90
99.80
99.50
99
98
95
90
z 80
UJ
o 70
or
uj 60
a.
50
> 40
£ 30
^
_j
=> 20
2
D
o 10
5
2
1
0.5
0.2
0.15
O.I
no
TOTAL PARTICULATE =2.1 kg PARTICIPATE
- EMISSION RATE Mg METAL
-MELTED (PRODUCED)
M
^m
»
»
^
I
1
/
A
A7^
s^
£r^ \
-
_
-
-
-
-
-
iii i i i 1 1 1 1 i i i i 1 1 1 1 1 i i i i i 1 1 1
UJ
N
V>
a
UJ
V)
V
1.51 u
i
r-
^^
1.03 o
P
0.71 ^
a.
0.50
0.42 *
0.40^
UJ
H
|
0
-1
1-
UJ
2
o>
2
10"' 10° 10 ' 10'
PARTICLE DIAMETER, micrometers
Figure 7.10-7. Particle size distribution for uncontrolled
pouring and cooling.25
10/86
Metallurgical Industry
A-18
7.10-17
-------
99.990
99.990
99.90
99.80
99.50
99
98
95
90
z
Ul
u
or
ui
D
2
80
70
60
50
40
30
20
10
5
2
I
6.5
0.2
0.15
O.I
0.0
10*
TOTAL PARTICIPATE = 1.60
EMISSION RATE
kg PARTICULATE
Mg METAL
MELTED/ (PRODUCED)
1.60
UJ
N
CO
a
u
t-
<
to
V
1.12
0.70
0.67
0.66
0.59
0.37
UJ
2
D
U
10° 10' ios
PARTICLE DIAMETER, micrometers
UJ
2
Figure 7.10-8. Particle size distribution for uncontrolled shakeout.26
7.10-18
EMISSION FACTORS
A-19
10/86
-------
REFERENCES FOR SECTION 7.10
1. Summary of Factors Affecting Compliance by Ferrous Foundries, Volume I;
Text, EPA-340/1-80-020, U. S. Environmental Protection Agency,
Washington, DC, January 1981.
2. Air Pollution Aspects of the Iron Foundry Industry, APTD-0806, U. S.
Environmental Protection Agency, Research Triangle Park, NC, February 1971.
3. Systems Analysis of Emissions and Emission Control in the Iron Foundry
Industry, Volume II; Exhibits, APTD-0645, U. S. Environmental Protection
Agency, Research Triangle Park, NC, February 1971.
4. J. A. Davis, et al., Screening Study on Cupolas and Electric Furnaces in.
Gray Iron Foundries, EPA Contract No. 68-01-0611, Battelle Laboratories,
Columbus, OH, August 1975.
5. R. W. Hein, et al., Principles of Metal Casting, McGraw-Hill, New York,
1967.
6. P. Fennelly and P. Spawn, Air Pollution Control Techniques for Electric Arc
Furnaces in the Iron and Steel Foundry Industry, EPA-450/2-78-024, U. S.
Environmental Protection Agency, Research Triangle Park, NC, June 1978.
7. R. D. Chmielewski and S. Calvert, Flux Force/Condensation Scrubbing for
Collecting Fine Particulate from Iron Melting Cupola, EPA-600/7-81-148,
U. S. Environmental Protection Agency, Research Triangle Park, NC,
September 1981.
8. W. F. Hammond and S. M. Weiss, "Air Contaminant Emissions From Metallurgi-
cal Operations In Los Angeles County", Presented at the Air Pollution Con-
trol Institute, Los Angeles, CA, July 1964.
9. Particulate Emission Test Report On A Gray Iron Cupola at Cherryville
Toundry Works, Cherryville, NC, Department Of Natural And Economic Re-
sources, Raleigh, NC, December 18, 1975.
10. J. N. Davis, "A Statistical Analysis of the Operating Parameters Which
Affect Air Pollution Emissions From Cupolas", November 1977. Further
information unavailable.
11. Air Pollution Engineering Manual, Second Edition, AP-40, U. S. Environ-
mental Protection Agency, Research Triangle Park, NC, May 1973. Out of
Print.
12. Written communication from Dean Packard, Department Of Natural Resources,
Madison, WI, to Douglas Seeley, Alliance Technology, Bedford, MA, April
15, 1982. I
13. Particulate Emissions Testing At Opelika Foundry, Birmingham. AL. Air
Pollution Control Commission, Montgomery, AL, November 1977 - January 1978.
14. Written communication from Minnesota Pollution Control Agency, St. Paul
MN, to Mike Jasinski, Alliance Technology, Bedford, MA, July 12, 1982.
10/86 Metallurgical Industry 7 10-19
A-20
-------
15. Stack Test Report, Dunkirk Radiator Corporation Cupola Scrubber, State
Department Of Environmental Conservation, Region IX, Albany, NY, November
1975.
16. Particulate Emission Test Report For A Scrubber Stack For A Gray Iron
Cupola At Dewey Brothers, Goldsboro, NC, Department Of Natural Resources,
Raleigh, NC, April 7, 1978.
17- Stack Test Report, Worthington Corp. Cupola, State Department Of Environ-
mental Conservation, Region IX, Albany, NY, November 4-5, 1976.
18. Stack Test Report, Dresser Clark Cupola Wet Scrubber, Orlean, NY, State
Department Of Environmental Conservation, Albany, NY, July 14 & 18, 1977.
19. Stack Test Report, Chevrolet Tonawanda Metal Casting, Plant Cupola //3 And
Cupola #4, Tonawanda, NY, State Department Of Environmental Conservation,
Albany, NY, August 1977.
20. Stack Analysis For Particulate Emission, Atlantic States Cast Iron Foun-
dry/Scrubber, State Department Of Environmental Protection, Trenton, NJ,
September 1980.
21. S. Calvert, et al., Fine Particle Scrubber Performance, EPA-650/2-74-093,
U. S. Environmental Protection Agency, Cincinnati, OH, October 1974.
22. S. Calvert, et al. , National Dust Collector Model 850 Variable Rod Module
Venturi Scrubber Evaluation, EPA-600/2-76-282, U. S. Environmental Protec-
tion Agency, Cincinnati, OH, December 1976.
23. Source Test, Electric Arc Furnace At Paxton-Mitchell Foundry, Omaha, NB,
Midwest Research Institute, Kansas City, MO, October 1974.
24. Source Test, John Deere Tractor Works, East Moline, IL, Gray Iron Electric
Arc Furnace, Walden Research, Wilmington, MA, July 1974
25. S. Gronberg, Characterization Of Inhalable Particulate Matter Emissions
From An Iron Foundry, Lynchburg Foundry, Archer Creek Plant, EPA-600/X-
85-328, U. S. Environmental Protection Agency, Cincinnati, OH, August 1984.
26. Particulate Emissions Measurements From The Rotoclone And General Casting
Shakeout Operations Of United States Pipe & Foundry, Inc, Anniston, AL,
State Air Pollution Control Commission, Montgomery, AL. Further informa-
tion unavailable.
27. Report Of Source Emissions Testing At Newbury Manufacturing, Talladega, AL,
State Air Pollution Control Commission, Montgomery, AL, May 15-16, 1979.
28. Particulate Emission Test Report For A Gray Iron Cupola At Hardy And New-
son, La Grange, NC, State Department Of Natural Resources And Community
Development, Raleigh, NC, August 2-3, 1977.
29. H. R. Crabaugh, et al., "Dust And Fumes From Gray Iron Cupolas: How Are
They Controlled In Los Angeles County", Air Repair, 4^3): 125-130, November
1954.
7.10-20 EMISSION FACTORS 10/86
A-21
-------
30. J. M. Kane, "Equipment For Cupola Control", American Foundryman's Society
Transactions, £4^525-531, 1956.
31. Control Techniques For Lead Air Emissions, 2 Volumes, EPA-450/2-77-012, U.
S. Environmental Prote^:ion Agency, Research Triangle Park, NC, December
1977.
32. W. E. Davis, Emissions Study Of Industrial Sources Of Lead Air Pollutants,
1970, APTD-1543, U. S. Environmental Protection Agency, Research Triangle
Park, NC, April 1973.
33. Emission Test No. EMB-71-CI-27, Office Of Air Quality Planning and Stan-
dards, U. S. Environmental Protection Agency, Research Triangle Park, NC,
February 1972.
34. Emission Test No. EMB-71-CI-30, Office Of Air Quality Planning And Stan-
dards, U. S. Environmental Protection Agency, Research Triangle Park, NC,
March 1972.
35. John Zoller, et al., Assessment Of Fugitive Particulate Emission Factors
For Industrial Processes, EPA-450/3-78-107, U. S. Environmental Protection
Agency, Research Triangle Park, NC, September 1978.
36. J. Jeffery, et al. , Inhalable Particulate Source Category Report For The
Gray Iron Foundry Industry, TR-83-15-G, EPA Contract No. 68-02-3157, GCA
Corporation, Bedford, MA, July 1986.
10/86 Metallurgical Industry 7.10-21
A-22
-------
Appendix B. Toxic Air Pollutant Emission Factors for Iron Foundries9
nc
COOt (MISSION SCUtCE
sec
POUUTAXT
.CAS
kUHBE* EMISSION fACIO*
NOUS
tri
I
112 Cupola
332 Cupel
332 Cupol*
332 Cupoli
332 CupoU
332 Induction furruct
332 Iltctrle «r« furruct
332 Electric »re furntc*
3321 Cupol.
30400301 MingMtett
30(00301 Htngineit
30400301 M.og.nete
3W0030I M«n«MMit
3M00301 Htngmeti
3M00303 .Ntngtneit
30(003M
30100304
3 M 0030 I Copper
7A3W45 0.25 Ib/ton of Iron
743°96S 0.12 Ib/ton of Iron
7(3°9eS 0.073 Ib/ton of Iron
7439945 0.012 Ib/ton of Iron
7439965 0.003 Ib/ton of Iron.
7O99A5 0.022S Ib/ton of Iron
7U9945 0.15 Ib/ton of Iron
7O99&5 0.0015 Ib/ton of Iron
7U05M 0.0017 kg/Mg «r»r Iron
produced
Uncontrolled, olcuttttd bated on
engineering judgement
Controlled by wet c»p, olculited
btsed on engineering Judgement
Controlled by Irplngenent
tcrufctxr, olcuUtrd baied on
engineering Judgement
Controlled by high energy
icrubber, olcuUled b*:ed on
engineering Judgement
Controlled by febrlc (llttr,
olculited beted on engineering
Judgement
Uncontrolled, cilculitcd luted on
engineering Judgement
Uncontrolled, cilculxtd bated on
engineering judgement
Controlled by f.brlc filter (991),
olculxed tuted on engineering
Judgment
Uncontrolled, copper content
0.021. PH l.clort
-------
Appendix C. Criteria Air Pollutant Emission Factors for Gray Iron Foundries
sec
3-04-003-01
3-04-003-02
3-04-003-03
3-04-003-04
3-04-003-05
3-04-003-10
3-04-003-15
3-04-003-20
3-04-003-25
3-04-003-31
3-04-003-32
3-04-003-33
3-04-003-40
3-04-003-41
3-04-003-42
3-04-003-50
3-04-003-51
3-04-003-52
3-04-003-53
3-04-003-54.
3-04-003-55
3-04-003-56
3-04-003-57
3-04-003-58
3-04-003-60
3-04-003-70
3-04-003-71
3-04-003-98
3-04-003-99
Process
Name
- Cupola
- Reverberator/
Furnace
- Electric Induction
Furnace
- Electric Arc Furnace
- Annealing Operation
Inoculation
- Charge Handling
- Pouring/Catting
- Catling* Cooling
- Casting Shakeout
- Casting Knock Out
- Shakeout Machine
- Grinding/Cleaning
- Casting Cleaning/
Tunblert
- Casting Cleaning/
Chippers
- Sand Grinding /
Handling
- Core Ovens
- Sand Grinding /
Handling
- Core Ovens
Core Ovens
- Sand Dryer
Sand Silo
- Conveyors/Elevators
- Sand Screens
- Castings Finishing
- Shell Core Machine
- Core Machines/Other
- Other Not Classified
- Other Mot Classified
PART
Lbs/Unil
13.8
2.1
0.9
12.7
...
4.0
0.6
2.8
1.4
3.2
* *
...
17.0
*
0.65 (c)
2.71 (c)
40.0
3.6
...
...
...
...
...
0.01 (c)
...
...
XXX
PM10
Lbs/Unlt
12.4
1.7
0.86
11.4
...
3.2
0.36
5.0
10.0
2.24
...
...
1.7
...
...
0.54
2.22
6.0
...
...
...
...
...
...
0.0045
...
...
XXX
SOx
Lbs/Unit
0.9
180.0
0.0
0.25
...
...
0.0
0.02
0.0
0.0
0.0
0.0
0.0
o.b
o.p
0.0
0.32
0.0
0.32
0.33
0.0
0.0
0.0
0.0
0.0
0.32
0.32
...
XXX
NOx
Lbs/Unlt
0.1
5.8
0.0
0.32
1.0
...
0.0
0.01
0.0
0.0
0.0
0.0
0.0
o.p
.0.0
0.0
0.5
0.0
0.5
0.5
1.6
0.0
0.0
0.0
0.0
0.5
0.5
...
XXX
voc
Lbs/Unlt
0.18
0.15
0.0
0.18
0.1
0.005
0.0
0.14
0.0
1.2
1.2
1.2
0.0
0.0
0.0
0.0
0.0008
0.0
0.0008
0.0008
0.004
0.0
0.0
0.0
0.0
0.0008
0.0008
...
XXX
CO LEAD UNITS
Lbs/Unlt Lbs/Unit
145.0 0.51 Tons of Metal Charged
0.0 0.06 Tons of Metal Charged
0.0 0.0425 Tons of Metal Charged
19.0 Tons of Hctol Charged
Tons Processed
--- Tons of Hetal
Inoculated
Tons of Hetal Charged
Tons of Hetal Charged
-- Tons of Hetal Charged
Tons of Hetal Charged
Tons Sand Handled
Tons Sand Handled
0.0 Tons of Metal Charged
Tons Castings Cleaned
.--- --- Tons Castings Cleaned
-- Tons Sand Handled
Tons Sand Handled
--- Tons of Metal Charged
Tons of Hetal Charged
--- Gallons of Core Oil
Used
Tons Sand Handled
Tons Sand Handled
--- Tons Sand Handled
Tons Sand Handled
Tons of Hetal Charged
-'- Tons of Cores
Produced
Tons of Cores
Produced
Gallons
XXX XXX Tons of Hetal Charged
-------
Appendix D.
Threshold
(Copyrighted.
Limit Values and Biological Exposure Indices for 1989 - 1990
Reproduced with permission.)
Particle SIze-Selecllve Sampling Criteria lor
Airborne Participate Mailer
For chemical substances present In Inhaled air as suspen-
sions o( solid particles or droplets, tho potential hazard depends
on particle size as wel as mass concentration because of: 1) effects
ol particle size on deposition site within the respiratory tract, and
2) the tendency (or many occupational diseases to be associated
with material deposited In particular regions ol the respiratory tract.
ACGIH has recommended particle size-selective TLVs lor crys-
talline silica for many years In recognition of the well established
association between sllicosls and resplrable mass concentrations.
It now has embarked on a re-examlnatlon of other chemical sub-
stances encountered In participate form In occupational environ-
ments with the objective of defining: 1) the size-lractlon most closely
associated for each substance with the health olfecl ol concern,
and 2) the mass concentration within that size fraction which should
represent the TLV.
The Particle Size-Selective TLVs (PSS-TLVs) win be expressed
In three forms, e.g.,
a. /nsplraoto Paniculate Mp-« TLVs (IPM-TLVs) for those materials
which are hazardous when deposited anywhere In the respira-
tory tract.
b. Thoracte Paniculate Mass TLVs (TPM-TLVs) (or inose matenali
which are hazardous when deposited anywhere within the lung
airways and the gas-exchange region.
c. Rosplrabto Panlculato Mass TLVs (RPM-TLVs) lor those male-
rials which are hazardous when deposited In the gas-exchange
region.
Tho three paniculate mass fractions described above are defined
In quantitative terms as follows:
o. Insplrable Paniculate Mass consists ortliose particles' that are
captured according to the following collection efficiency regard-
loss ol sampler orientation with respect to wind direction:.
E - 50(1 + cxp[-0.06 d.l) ±10.
forO 100 pm are presently
unknown. E Is collection efficiency In percent and d. Is aero-
dynamic diameter In pm.
b. Thoracic Particulate Mass consists ol those particles that pene-
trate a separator whose size collection efficiency Is described
by * cumulative lognormal function with a median aerodynamic
diameter of 10 pm ±1.0 pm and with a geometric standard
deviation of 1.5 (±0.1).
c. Ftesplrable Particular Mass consists of those particles that
penetrate a separator whose size collection efficiency Is
described by a cumulative lognormal function with a median
aerodynamic diameter of 3.5 nm ± 0.3 jim and with a geometric
standard deviation of 1.5 (±0.1). This Incorporates and clari-
fies the previous ACGIH Resplrable Oust Sampling Criteria.
These definitions provide a range of acceptable performance (or
each type of size-selective sampler. Further information Is availa-
ble on the background and performance criteria for these particle
size-selective sampling recommendations.1'1
References
1. ACGIH: Ptrtidt Sltt-Selectht Sinpfinj In Itie Woritpttoe. 60 pp. OndnnX. Ohio
(ISW).
Chemical Substances and Other Issues Under Study
Information, data especially, nnd comments are solicited to assist
the Committee In Its deliberations and In the possible developmenl
of draft documents. Draft documentations are used by the Com-
mittee to decide what action, II any, to recommend on a given
question.
Chemlctl Substances
Acetaldehyde
Acetomelhylchlorlde
Acetophenone
Acryflc acid
Adlplc acid
Adlponltrile
Benlonlle
Benzyl acetate
Borax and boron compounds
Bromine pentafluoride
Bromochloromelhana
Bromodichloromethane
Bromolorm
n-Butyl acetate
2-l-8utylazc-2-hydroxy-5-
melhylhexane
Cadmium
Carbon disulflde
Carbon monoxide
Chromium
Chrysene
Dlbutyl phenyl phosphate
Dlchlorodlphenyl sulfone
Dlchlorocyclopenladlene
2,4-D (2,4rDlchlorophenoxy
acetic acid)
1,3-Olchloropropene
Dichlorvos
Dlethylamlne
Dimelhylamlm
Dimethyl acelamldo
Dimethyl formamlde
Dimethyl disulflde
Dinllrololuene
Eplchlorohydrln
EPN
Ethyl bromide
2-Elhyt hexanolc acid
Gallium arsenide
Gasoline (unleaded)
Glutaraldehyde
Glycol ethers
Graphite libers
Heplachlor
Hoxachlorobonzono
Hexachlorocyclopentadiene
Hexamethylene diamlne
Jet, petroleum and dlesel fuel
Inorganic lead
Malalhloh
Man-made mineral fibers
2-Melhoxyelhanol
Methyl bromide
Melhylene diamine
4,4'-Melhy1ene dianiline
Methyl lert-bulyl ether
Mineral spirits
Naled
Nilromolhanc
Penlachlorophenol
2,4-Pentanedione
Perchloroelhylene
Periluorolsobutylene
Persulfales
Pelroleum solvents
Propylene dichloride
Sulfur telrafluorlde
Sulfuryl (luorido
Tantalum
Terphenyls
Terephlhalic acid
1.1.1,2-Telrachloro-
2.2-dilluoroelhane
1.1.2.2-Telrachloro-
1,2-dilluoroolhano
1,1,2,2-Tolrachlofoelhano
Telrakls phosphonlum
chloride
Tetrakis phosphonlum sulfale
Telrasodium pyrophosphale
Tobacco smoke
Trichloroelhylene
Trielhanolamine
Trielhylamine
Vinyl cyclohexcnc
Uranium
Other Issues
1. Solubility.
2. Should the TLVs currenlly expressed as "total dust" be
changed lo "inspirable paniculate mass." as defined In Ap-
pendix D, without changing the numerical value?
3. Two working groups have been formed lo address questions ol:
a. Altered work shifts.
b. Skin notation criteria.
4. Excursion limits
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-90-044
2.
3. RECIPIENT'S ACCESSION.NO.
4. TITLE AND SUBTITLE
Emission Factors for Iron Foundries--Criteria and
Toxic Pollutants
5. REPORT DATE
August 1990
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Gerhard Gschwandtner and Susan Fairchild
t. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
E. H. Pechan and Associates, Inc.
3514 University Drive
Durham, North Carolina 27707
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D9-0168, Task 5
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air and Energy Engineering Research Laboratory
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD. CQ1
Task Final; 11/89 - 5/90
VERED
14. SPONSORING AGENCY CODE
EPA/600/13
is. SUPPLEMENTARY NOTES AEERL project officer is Robert C. McCrillis, Mail Drop 61,
919/541-2733.
is. ABSTRACT
report iis^s criteria and toxic pollutant emission factors for sources
commonly found in gray and ductile iron foundries. Emission factors are identified
for process source and process fugitive emissions,. The emission factors, represen-
ting uncontrolled emissions, may be used to estimate emissions when site- specific
information and data are not available.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution
Foundries
Emission
Toxicity
Pollution Control
Stationary Sources
Emission Factors
Criteria Pollutants
Toxic Pollutants
13B
131
14G
06T
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport/
Unclassified
21. NO. OF PAGES
62
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
iPA Form 2220-1 (9-73)
D-2
------- |