BACKGROUND REPORT
AP-42 SECTION 12.8
SECONDARY ALUMINUM
Prepared for
U.S. Environmental Protection Agency
OAQPS/TSD/EIB
Research Triangle Park, NC 27711
1-103
Pacific Environmental Services, Inc.
P.O. Box 12077
Research Triangle Park, NC 27709
919/941-3536
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1-103
AP-42 Background Report
TECHNICAL SUPPORT DIVISION
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
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This report has been reviewed by the Technical Support Division of the Office of Air Quality
Planning and Standards, EPA. Mention of trade names or commercial products is not intended to
constitute endorsement or recommendation for use. Copies of this report are available through the
Library Services Office (MD-35), U.S. Environmental Protection Agency, Research Triangle Park,
NC 27711.
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TABLE OF CONTENTS
1.0	INTRODUCTION	 1
2.0	INDUSTRY DESCRIPTION	 2
2.1	GENERAL 	 2
2.2	PROCESS DESCRIPTION	 2
2.3	EMISSIONS AND CONTROLS	 10
2.4	REVIEW OF REFERENCES	 15
2.5	REFERENCES FOR CHAPTER 2 	16
3.0	GENERAL EMISSION DATA REVIEW AND ANALYSIS
PROCEDURES	 19
3.1	LITERATURE SEARCH AND SCREENING	 19
3.2	EMISSION DATA QUALITY RATING SYSTEM	 20
3.3	EMISSION FACTOR QUALITY RATING
SYSTEM	 22
3 .4	REFERENCES FOR CHAPTER 3 	 24
4.0	POLLUTANT EMISSION FACTOR DEVELOPMENT		25
4.1	CRITERIA POLLUTANT EMISSIONS DATA 		25
4.2	NONCRITERIA POLLUTION EMISSION DATA		32
4.3	REVIEW OF SPECIFIC DATA SETS 		32
4.4	DATA GAP ANALYSIS		35
4.5	REFERENCES FOR CHAPTER 4 		38
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LIST OF TABLES
TABLE 2.3-1 (METRIC): PARTICULATE EMISSION FACTORS FOR
SECONDARY ALUMINUM OPERATIONS	 12
TABLE 2.3-1 (ENGLISH): PARTICULATE EMISSION FACTORS FOR
SECONDARY ALUMINUM OPERATIONS	 13
TABLE 2.3-2. (METRIC): PARTICLE SIZE DISTRIBUTION AND SIZE-
SPECIFIC EMISSION FACTORS 	 17
TABLE 2.3-2. (ENGLISH): PARTICLE SIZE DISTRIBUTION AND
SIZE-SPECIFIC EMISSION FACTORS	 18
TABLE 4.1-1 (METRIC): CARBON MONOXIDE	 26
TABLE 4.1-1 (ENGLISH): CARBON MONOXIDE	 27
TABLE 4.1-2 (METRIC): TOTAL SUSPENDED PARTICULATE AND
P\1 	 30
TABLE 4.1-2 (ENGLISH): TOTAL SUSPENDED PARTICULATE AND
PM 	 31
TABLE 4-4: LIST OF CONVERSION FACTORS	 37
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LIST OF FIGURES
FIGURE 2.2-1A 		4
FIGURE 2.2-IB 		5
FIGURE 2.2-2		7
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1.0	INTRODUCTION
The document "Compilation of Air Pollutant Emission Factors" (AP-42) has been published
by the U.S. Environmental Protection Agency (the EPA) since 1972. Supplements to AP-42 have
been routinely published to add new emission source categories and to update existing emission
factors. AP-42 is routinely updated by the EPA to respond to new emission factor needs of the
EPA, State, and local air pollution control programs and industry.
An emission factor relates the quantity (weight) of pollutants emitted to a unit of activity of
the source. The uses for the emission factors reported in AP-42 include:
1.	Estimates of area-wide emissions;
2.	Emission estimates for a specific facility; and
3.	Evaluation of emissions relative to ambient air quality.
The purpose of this report is to provide background information from process information
obtained from industry comment and one test report to support future revision of emission factors
for secondary aluminum industry.
Including the introduction (Chapter 1) this report contains four chapters. Chapter 2 gives a
description of the secondary aluminum industry. It includes a characterization of the industry, an
overview of the different process types, a description of emissions, and a description of the
technology used to control emissions resulting from recycling aluminum metal.
Chapter 3 is a review of emissions data collection and analysis procedures. It describes the
literature search, the screening of emission data reports, and the quality rating system for both
emission data and emission factors. Chapter 4 details criteria and noncriteria pollutant emission
factor development. It includes the review of specific data sets and the results of data analysis.
Particle size determination and particle size data analysis methodology are described.
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2.0	INDUSTRY DESCRIPTION
2.1	GENERAL
Secondary aluminum producers recycle aluminum from aluminum-containing scrap, while
primary aluminum producers convert bauxite ore into aluminum. The secondary aluminum
industry was responsible for 27.5 percent of domestic aluminum produced in 1989. There are
approximately 116 plants with a recovery capacity of approximately 2.4 million megagrams (2.6
million tons) of aluminum per year. Actual total secondary aluminum production was relatively
constant during the 1980s. However, increased demand for aluminum by the automobile industry
has doubled in the last ten years to an average of 78.5 kilograms (173 pounds) per car. Recycling
of used aluminum beverage cans (UBC) increased more than 26 percent from 1986 to 1989. In
1989, 1.3 billion kilograms (2.9 billion pounds) of UBCs were recycled, representing over 60
percent of cans shipped. Recycling aluminum requires only five percent of the energy required to
refine primary aluminum from bauxite ore, making the secondary aluminum economically viable.
2.2	PROCESS DESCRIPTION
Pacific Environmental Services (PES) contacted the following sources to obtain the most up-
to-date information on process descriptions and emissions for this industry:
1)	ALCOA, Pittsburgh, PA.
2)	Noranda Aluminum, Inc., Brentwood, TN.
3)	Chas Licht Engineering Assoc., Inc., Aurora, IL.
4)	Noranda Aluminum, Inc., New Madrid, MO.
5)	Reynolds Aluminum Recycling, Richmond, VA.
6)	U.S. Reduction, Inc., Munster, IN.
The Aluminum Association, Washington, DC.
The Aluminum Recycling Association, Washington, DC.
ALCAN Aluminum Corporation, Cleveland, OH.
10)	Metallics Systems, Inc., Solon, OH.
11)	The Carborundum Company, Solon, OH.
12)	Ross Brothers Smelting Corporation, East Syracuse, NY.
13)	State of New Jersey, Dept. of Environmental Protection.
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Responses have primarily been related to process operations, with receipt of one emission
test. Process information and source emission data was requested from each of the above
organizations. Respondents included ALCOA, The Aluminum Association, U.S. Reduction, The
Carborundum Company, Ross Brothers Smelting Corporation, and the State of New Jersey. The
State of New Jersey sent an excellent source emission test using EPA method 5. Pacific
Environmental Services has incorporated relevant information received from these sources into the
AP-42 background report.
Secondary aluminum production involves two general categories of operations, scrap
pretreatment and smelting/refining. Pretreatment operations include sorting, processing and
cleaning scrap. Smelting/refining operations include cleaning, melting, refining, alloying, and
pouring of aluminum recovered from scrap. The processes used to convert scrap aluminum to
products such as lightweight aluminum alloys for industrial castings are presented in Figures 2.2-
1A and 2.2-1B. Some or all the steps in these figures may be involved at any one facility. Some
steps may be combined or reordered, depending on scrap quality, source of scrap, auxiliary
equipment available, furnace design, and product specifications. Plant configuration, scrap type
usage, and product output varies throughout the secondary aluminum industry.
Scrap Pretreatment
Aluminum scrap comes from a variety of sources. "New" scrap is generated by pre-
consumer sources, such as drilling and machining of aluminum castings, scrap from aluminum
fabrication and manufacturing operations, and aluminum bearing residual
material (dross) skimmed off molten aluminum during smelting operations. "Old" aluminum scrap
is material that has been used by the consumer and discarded. Examples of old scrap include used
appliances, aluminum foil, automobile and airplane parts, aluminum siding, and beverage cans.
Scrap pretreatment involves sorting and processing scrap to remove contaminants and to
prepare the material for smelting. Sorting and processing separates the aluminum from other
metals, dirt, oil, plastics, and paint. Pretreatment cleaning processes are based on mechanical,
pyrometallurgical and hydrometallurgical techniques.
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PRETREATMENT
BALING
FUEL
FUEL
FLUX
DRY MILLING
LEACHING
WATER
FUEL
FOIL
ROASTING
FUEL
CABLE
SWEATING
RESIDUES
INSPECTION
SORTING
BULK SCRAP
HIGH IRON
SCRAP
CRUSHING
SCREENING
BORINGS,
TURNINGS
BURNING,
DRYING
HOT DROSS
PROCESSING
SHREDDING/
CLASSIFYING
CRUSHING,
SCREENING
NEW CLIPPINGS,
FORGINGS
OLD SHEET
CASTINGS
CLIPPINGS
TREATED
ALUMINUM
SCRAP
HEAVY METALLIC
SKIMS
Figure 2.2-1 A Typical process diagram for secondary aluminum processing industry
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SMELTING/REFINING
PRODUCT
	CHLORINE
I	FLUX
r-FUEL
I	FLUORINE
|	FLUX
r—fuel
•FLUX
•FUEL
I—FLUX
	FUEL
SHOT
BILLETS
NOTCHED
BARS
HARDENERS
HOT
METAL
ALLOY
INGOTS
TREATED
ALUMINUM
SCRAP
REVERBERATORY
(FLUORINE)
SMELTING/REFINING
REVERBERATORY
(CHLORINE)
SMELTING/REFINING
CRUCIBLE
SMELTING/REFINING
INDUCTION
SMELTING/REFINING
Figure 2.2-IB Typical process diagram for secondary aluminum processing industry
(continued)
Mechanical Cleaning
Mechanical cleaning includes the physical separation of aluminum from other scrap, with
hammer mills, ring rushers, and other machines to break scrap containing aluminum into
smaller pieces. This improves the efficiency of downstream recovery by magnetic removal of iron.
Other recovery processes include vibratory screens and air classifiers.
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An example of mechanical cleaning is the dry milling process. Cold aluminum-laden dross
and other residues are processed by milling and screening to obtain a product containing at least 60
to 70 percent aluminum. Ball, rod or hammer mills can be used to reduce oxides and nonmetallic
particles to fine powders for ease of removal during screening.
Pyrometallurgical Cleaning
Pyrometallurgical techniques (called drying in the industry) use heat to separate aluminum
from contaminates and other metals. Pyrometallurgical techniques include roasting and sweating.
The roasting process involves heating aluminum scrap that contains organic contaminates in rotary
dryers to temperatures high enough to vaporize or carbonize organic contaminates, but not high
enough to melt aluminum (660°C; 1220°F). An example of roasting is the APROS delacquering
and preheating process used during the processing of used beverage cans (shown in Figure 2.2-2).
The sweating process involves heating aluminum scrap containing other metals in a sweat furnace
to temperatures above the melting temperature of aluminum, but below that of the other metal. For
example, sweating recovers aluminum from high iron content scrap by heating the scrap in an open
flame reverberatory furnace. The temperature is raised and maintained above the melting
temperature of aluminum, but below the melting temperature of iron. This condition causes
aluminum and other low melting constituents to melt and trickle down the sloped hearth, through a
grate and into air cooled molds or collecting pots. This product is called "sweated pig." The
higher-melting materials, including iron, brass, and the oxidation products formed during the
sweating process, are periodically removed from the furnace.
In addition to roasting and sweating, a catalytic technique may also be used to clean
aluminum dross. Dross is a layer of impurities and semisolid flux that has been skimmed from the
surface of molten aluminum. Aluminum may be recovered from dross by batch fluxing with a
salt/cryolite mixture in a mechanically rotated, refractory-lined barrel furnace. Cryolite acts as a
catalyst that decreases aluminum surface tension and therefore increases recovery rates. Aluminum
is tapped periodically through a hole in the base of the furnace.
Hydrometallurgical Cleaning
Hydrometallurgical techniques use water to clean and process aluminum scrap.
Hydrometallurgical techniques include leaching and heavy media separation. Leaching is used to
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Scrap
Aluminum
Dust Collector

Airlock
Fines
Hot Gas
Recycle Fan
Rotary Kiln
Discharge
Airlock
Reverberatory
Furnace
Heated, Recycle Gas
Combustor
Fuel
Figure 2.2-2 APROS delacquering and preheating process
recover aluminum from dross, furnace skimmings, and slag. It requires wet milling, screening,
drying, and finally magnetic separation to remove fluxing salts and other waste products from the
aluminum. First, raw material is fed into a long rotating drum or a wet ball mill where water
soluble contaminants are rinsed into waste water and removed (leached). The
remaining washed material is then screened to remove fines and undissolved salts. The screened
material is then dried and passed through a magnetic separator to remove ferrous materials.
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The heavy media separation hydrometallurgical process separates high density metal from
low density metal using a viscous medium, such as copper and iron, from aluminum. Heavy media
separation has been used to concentrate aluminum recovered from shredded cars. The cars are
shredded after large aluminum components have been removed (shredded material contains
approximately 30 percent aluminum) and processed in heavy media to further concentrate
aluminum to 80 percent or more.
Smelting/Refining
After scrap pretreatment, smelting and refining is performed. Smelting and refining in
secondary aluminum recovery takes place primarily in reverberatory furnaces. These furnaces are
brick-lined and constructed with a curved roof. The term reverberatory is used because heat rising
from ignited fuel is reflected (reverberated) back down from the curved furnace roof and into the
melted charge. A typical reverberatory furnace has an enclosed melt area where the flame heat
source operates directly above the molten aluminum. The furnace charging well is connected to the
melt area by channels through which molten aluminum is pumped from the melt area into the
charging well. Aluminum flows back into the melt section of the furnace under gravity.
Most secondary aluminum recovery facilities use batch processing in smelting and refining
operations. It is common for one large melting reverberatory furnace to support the flow
requirements for two or more smaller holding furnaces. The melting furnace is used to melt the
scrap, remove impurities and entrained gases. The molten aluminum is then pumped into a holding
furnace. Holding furnaces are better suited for final alloying, and for making any additional
adjustments necessary to insure that the aluminum meets product specifications. Pouring takes
place from holding furnaces, either into molds or as feed stock for continuous casters.
Smelting and refining operations can involve the following steps: charging, melting, fluxing,
demagging, degassing, alloying, skimming, and pouring. Charging consists of placing pretreated
aluminum scrap into a melted aluminum pool (heel) that is maintained in melting furnaces. The
scrap, mixed with flux material, is normally placed into the furnace charging well, where heat from
the molten aluminum surrounding the scrap causes it to melt by conduction. Flux materials
combine with contaminates and float to the surface of the aluminum, trapping impurities and
providing a barrier (up to 6 inches thick) that reduces oxidation of the melted aluminum. To
minimize aluminum oxidation (melt loss), mechanical methods are used to submerge scrap into the
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heel as quickly as possible. Scrap may be charged as high density bales, loosely packed bales, or as
dry shredded scrap that is continuously fed from a conveyor and into the vortex section of the
charging well. The continuous feed system is advantageous when processing uniform scrap directly
from a drier (such as a delacquering operation for UBCs).
Demagging reduces the magnesium content of the molten charge from approximately 0.5
percent to about 0.1 percent (a typical product specification). In the past, when demagging with
liquid chlorine, chlorine was injected under pressure to react with magnesium as the chlorine
bubbled to the surface. The pressurized chlorine was released through carbon lances directed under
the heel surface, resulting in high chlorine emissions.
A more recent chlorine aluminum demagging process has replaced the carbon lance
procedure. Molten aluminum in the furnace charging well gives up thermal energy to the scrap as
scrap is melted. In order to maintain high melt rates in the charging well, a circulation pump moves
high temperature molten aluminum from the melt section of the reverberatory furnace to the
charging well. Chlorine gas is metered into the circulation pump's discharge pipe. By inserting
chlorine gas into the turbulent flow of the molten aluminum at an angle to the aluminum pump
discharge, small chlorine-filled gas bubbles are sheared off and mixed rapidly in the turbulent flow
found in the pump's discharge pipe. In actual practice, the flow rate of chlorine gas is increased
until a slight vapor (aluminum chloride) can be seen above the surface of the molten aluminum.
Then the flow rate is decreased until no more vapor is seen. It is reported that chlorine usage
approaches the stoichiometric relationship using this process. Stack tests showing chlorine
emissions resulting from this procedure have not been made available. It is anticipated that
reductions of chlorine emissions will be reported in the future.
Other chlorinating agents or fluxes, such as anhydrous aluminum chloride or chlorinated
organics, are used in demagging operations. Demagging with fluorine is similar to demagging with
chlorine, except that aluminum fluoride (A1F3) is employed instead of chlorine. The A1F3 reacts
with magnesium to produce molten metallic aluminum and solid magnesium fluoride salt that floats
to the surface of the molten aluminum and is trapped in the flux layer.
Degassing is a process used to remove gases entrained in molten aluminum. High pressure
inert gases are released below the molten surface to violently agitate the melt. This agitation causes
the entrained gasses to rise to the surface to be absorbed in the floating flux. In some operations,
degassing is combined with the demagging operation. A combination demagging and degassing
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process has been developed that uses a ten percent concentration of chlorine gas mixed with a
nonreactive gas (either nitrogen or argon). The combined high pressure gases are force through a
hand held nozzle that has a designed distribution pattern of hole sizes across the face of the nozzle.
The resulting high turbulent flow and the diluted chlorine content primarily degasses the melt.
Chlorine emissions resulting from this process are not available.
Alloying combines aluminum with an alloying agent in order to change its strength and
ductility. Alloying agents include zinc, copper, manganese, magnesium, and silicon. The alloying
steps include an analysis of the furnace charge, addition of the required alloying agents, and then a
reanalysis of the charge. This iterative process continues until the correct alloy is reached.
The skimming operation physically removes contaminated semisolid fluxes (dross, slag or
skimmings) by ladling them from the surface of the melt. Skimming is normally conducted several
times during the melt cycle, particularly if the pretreated scrap contains high levels of
contamination. Following the last skimming, the melt is allowed to cool before pouring into molds
or casting machines.
The crucible smelting/refining process is used to melt small batches of aluminum scrap,
generally limited to 500 kg (1,100 lb) or less. The metal-treating process steps are essentially the
same as those of reverberatory furnaces.
The induction smelting and refining process is designed to produce aluminum alloys with
increased strength and hardness by blending aluminum and hardening agents in an electric
induction furnace. The process steps include charging scrap, melting, adding and blending the
hardening agent, skimming, pouring and casting into notched bars. Hardening agents include
manganese and silicon.
2.3	EMISSIONS AND CONTROLS
The major sources of emissions from scrap pretreatment processes are scrap crushing and
screening operations, scrap driers, sweat furnaces, and UBC delacquering systems. Although each
step in scrap treatment and smelting/refining is a potential source of emissions, emission factors for
scrap treatment processes have not been sufficiently characterized and documented and are
therefore not presented below.
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Smelting and refining emission sources originate from charging, fluxing, and demagging
processes. Table 2.3-1 presents emission factors for sweating furnaces, crucible furnaces,
reverberatory furnaces, and chlorine demagging process.
Scrap Pretreatment Emissions
Mechanical cleaning techniques involve crushing, shredding, and screening and produce
metallic and nonmetallic particulates. Burning and drying operations (pyrometallurgic techniques)
emit particulates and organic vapors. Afterburners are frequently used to convert unburned VOCs
to carbon dioxide and water vapor. Other gases that may be present, depending on the composition
of the contaminants, include chlorides, fluorides and sulfur oxides. Specific emission factors for
these gases are not presented due to lack of data. Oxidized aluminum fines blown out of the dryer
by the combustion gases contain particulate emissions. Wet scrubbers or fabric filters are
sometimes used in conjunction with afterburners.
Mechanically generated dust from rotating barrel dross furnaces constitutes the main air
emission of hot dross processing. Some fumes are produced from the fluxing reactions. Fugitive
emissions are controlled by enclosing the barrel furnace in a hood system and by ducting the
emissions to a fabric filter. Furnace offgas emissions, mainly fluxing salt fume, are often controlled
by a venturi scrubber.
Emissions from sweating furnaces vary with the feed scrap composition. Smoke may result
from incomplete combustion of organic contaminants (e.g., rubber, oil and grease, plastics, paint,
cardboard, paper) that may be present. Fumes can result from the oxidation of magnesium and zinc
contaminants and from fluxes in recovered dross and skims.
In dry milling, large amounts of dust are generated from the crushing, milling, screening, air
classification and materials transfer steps. Leaching operations (hydrometallurgic techniques) may
produce particulate emissions during drying. Particulate emissions from roasting result from the
charring of carbonaceous materials (ash).
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TABLE 2.3-1 (METRIC UNITS)
PARTICULATE EMISSION FACTORS FOR
SECONDARY ALUMINUM OPERATIONS3
All Emission Factors are in kg/Mg of Product
Ratings (A-E) Follow Each Factor
Operation
SCC's
Uncontro
led
Baghou
se
Electrc
precip
static
itator
Sweating furnaceb
3-04-001-01
7.25
E
1.65
E


Smelting
Crucible furnaceb
Reverberatoryc







3-04-001-02
0.95
E




3-04-001-03
2.15
E
0.65e
E
0.65
E
Chlorine demaggingd
3-04-001-04
500
E
25
E

E
Reference 2. Emission factors for sweating and smelting furnaces expressed as units per unit
weight of metal processed. For chlorine demagging, emission factor is kg/Mg (lb/ton) of chlorine
used.
b
Based upon averages of two source tests.
Uncontrolled, based on averages of ten source tests. Standard deviation of uncontrolled emission
factor is 1.75 kg/Mg that of controlled factor is 0.15 kg/Mg.
d
Based on average of ten source tests. Standard deviation of uncontrolled emission factor is 215
kg/Mg of control factor, 18 kg/Mg.
e
This factor may be lower if a coated baghouse is used.
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TABLE 2.3-1 (ENGLISH UNITS)
PARTICULATE EMISSION FACTORS FOR
SECONDARY ALUMINUM OPERATIONS3
All Emission Factors are in lb/ton of Product
Ratings (A-E) Follow Each Factor
Operation
SCC's
Uncontro
led
Baghou
se
Electrc
precip
static
itator
Sweating furnaceb
3-04-001-01
14.5
E
3.3
E


Smelting
Crucible furnaceb
Reverberatoryc







3-04-001-02
1.9
E




3-04-001-03
4.3
E
1.3e
E
1.3
E
Chlorine demaggingd
3-04-001-04
1000
E
50
E


Reference 2. Emission factors for sweating and smelting furnaces expressed as units per unit
weight of metal processed. For chlorine demagging, emission factor is kg/Mg (lb/ton) of chlorine
used.
b
Based upon averages of two source tests.
Uncontrolled based on averages of ten source tests. Standard deviation of uncontrolled emission
factor is 3.5 lb/ton, that of controlled factor is 0.3 lb/ton.
dBased on average of ten source tests. Standard deviation of uncontrolled emission factor is 430
lb/ton; of control factor, 36 lb/ton.
e
This factor may be lower if a coated baghouse is used.
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Smelting/Refining Emissions
Emissions from reverberatory furnaces represent a significant fraction of the total particulate and
gaseous effluent generated in the secondary aluminum industry. Emissions from the charging well
consist of organic and inorganic particulate, unburned organic vapors, and carbon dioxide.
Emissions from furnace burners contain carbon monoxide, carbon dioxide, sulfuric oxide, and
nitrogen oxide. Furnace burner emissions are usually separated from process emissions.
Emissions that result from fluxing operations are dependent upon both the type of fluxing agents
and the amount required, which are a function of scrap quality. Emissions may include common
fluxing salts such as sodium chloride, potassium chloride, and cryolite. Aluminum and magnesium
chloride also may be generated from the fluxing materials being added to the melt. Studies have
suggested that fluxing particulate emission are typically less than one micron in diameter. Specific
emission factors for these compounds are not presented due to lack of information.
In the past, demagging represented the most severe source of emissions for the secondary
aluminum industry. A more recent process change where chlorine gas is mixed into molten
aluminum from the furnace circulation pump discharge may reduce chlorine emissions. However,
total chlorine emissions are directly related to the amount of demagging effort and product
specifications (the magnesium content in the scrap and the required magnesium reduction). Also, as
the magnesium percentage decreases during demagging, a disproportional increase in emissions
could result due to the decreased efficiency of the scavenging process.
Both the chlorine and aluminum fluoride demagging processes create highly corrosive emissions.
Chlorine demagging results in the formation of magnesium chloride that contributes to fumes
leaving the dross. Excess chloride combines with aluminum to form aluminum chloride, a vapor at
furnace temperatures, but one that condenses into submicron particles as it cools. Aluminum
chloride has an extremely high affinity for water (hygroscopic) and combines with water vapor to
form hydrochloric acid. Aluminum chloride and hydrochloric acid are irritants and corrosive. Free
chlorine that does not form compounds may also escape from the furnace and become an emission.
Aluminum fluoride (A1F3) demagging results in the formation of magnesium fluoride as a
byproduct. Excess fluorine combines with hydrogen to form hydrogen fluoride. The principal
emissions resulting from aluminum fluoride demagging is a highly corrosive fume containing
aluminum fluoride, magnesium fluoride, and hydrogen fluoride. The use of A1F3 rather than
chlorine in the demagging step reduces demagging emissions. Fluorides are emitted as gaseous
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fluorides (hydrogen fluoride, aluminum and magnesium fluoride vapors, and silicon tetrafluoride)
or as dusts. Venturi scrubbers are usually used for gaseous fluoride emission control.
Table 2.3-2 presents particle size distributions and corresponding emission factors for
uncontrolled chlorine demagging and metal refining in secondary aluminum reverberatory furnaces.
According to the VOC/PM Speciate Database Management System (SPECIATE) database, the
following hazardous air pollutants (HAPs) have been found in emissions from reverberatory
furnaces: chlorine, and compounds of manganese, nickel, lead, and chromium. In addition to the
HAPs listed for reverberatory furnaces, general secondary aluminum plant emissions have been
found to include HAPs such as antimony, cobalt, selenium, cadmium, and arsenic, but specific
emission factors for these HAPs are not presented due to lack of information.
In summary, typical furnace effluent gases contain combustion products, chlorine, hydrogen
chloride and metal chlorides of zinc, magnesium and aluminum, aluminum oxide and various
metals and metal compounds, depending on the quality of scrap charged.
2.4	REVIEW OF REFERENCES
Specific changes to the process description expands the industry description and discusses the
newest method of demagging with chlorine using a circulation pump. In addition, process
information was expanded using published EPA documents and Shreve's Chemical Process
Industries, fifth edition, McGraw Hill, 1984.
Emission factors contained in emission tables in the section are downgraded to E. The reasons for
this change is discussed in Chapter 4.3.
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2.5	REFERENCES FOR CHAPTER 2
1.	W.M. Coltharp, et al., Multimedia Environmental Assessment of the Secondary Nonferrous
Metal Industry. Draft Final Report, 2 vols., EPA Contract No. 68-02-1319, Radian
Corporation, Austin, TX, June 1976.
2.	W.F. Hammond and S.M. Weiss, Unpublished report on air contaminant emissions from
metallurgical operations in Los Angeles County, Los Angeles County Air Pollution Control
District, July 1964.
3.	Emission test data from Environmental Assessment Data Systems, Fine Particle emission
Information System (EPEIS), Series Report No. 231, U. S. Environmental Protection
agency, Research Triangle Park, NC, June 1983.
4.	Environmental Assessment Data Systems, op.cit.. Series Report No. 331.
5.	Danielson, John., "Secondary Aluminum-Melting Processes." Air Pollution Engineering
Manual. 2nd Ed., U. S. Environmental Protection Agency, Washington, D.C., Report
Number AP-40, May 1973.
6.	Secondary Aluminum Reverberatory Furnace, Speciation Database. U.S. Environmental
Protection Agency. Research Triangle Park, NC. Profile Number 20101. 1989.
7.	Secondary Aluminum Plant—General, Speciation Database. U.S. Environmental Protection
Agency. Research Triangle Park, NC. Profile Number 90009. 1989.
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TABLE 2.3-2. (METRIC UNITS)
PARTICLE SIZE DISTRIBUTION AND SIZE-SPECIFIC EMISSION
FACTORS FOR UNCONTROLLED REVERBERATORY FURNACES IN
SECONDARY ALUMINUM OPERATIONS3
Ratings (A-E) Follow Each Factor

Particle size distribution13
Size specific emission factor0. ks/Ms
Aerodynamic
particle
diameter (um)
Chlorine
demagging
Refining
Chlorine
demagging
Rating
Refining
Rating
2.5
19.8
50.0
99.5
E
1.08
E
6.0
36.9
53.4
184.5
E
1.15
E
10.0
53.2
60.0
266.0
E
1.30
E
References 3-4.
bCumulative weight percent is less than the aerodynamic particle diameter, (jm.
cSize-specific emission factor equals total particulate emission factor multiplied by particle size
distribution, (percent)/100. From Table 12.8-1, total particulate emission factor for chloride
demagging is 500 kg/Mg chlorine used, and for refining, 2.15 kg/Mg aluminum processed.
17

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TABLE 2.3-2. (ENGLISH UNITS)
PARTICLE SIZE DISTRIBUTION AND SIZE-SPECIFIC EMISSION
FACTORS FOR UNCONTROLLED REVERBERATORY FURNACES IN
SECONDARY ALUMINUM OPERATIONS3
Ratings (A-E) Follow Each Factor

Particle size distribution13
Size specific emission factor0, lb/ton
Aerodynamic
particle
diameter (wm)
Chlorine
demagging
Refining
Chlorine
demagging
Rating
Refining
Rating
2.5
19.8
50.0
398
E
2.12
E
6.0
36.9
53.4
738
E
2.3
E
10.0
53.2
60.0
1,064
E
2.6
E
References 3-4.
bCumulative weight percent is less than the aerodynamic particle diameter, (jm.
cSize-specific emission factor equals total particulate emission factor multiplied by particle size
distribution, (percent)/100. From Table 2.3-1, total particulate emission factor for chloride
demagging is 1,000 lb/ton chlorine used, and for refining, 4.3 lb/ton aluminum processed.
18

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3.0
GENERAL EMISSION DATA REVIEW AND ANALYSIS PROCEDURES
3.1	LITERATURE SEARCH AND SCREENING
The first step of this investigation involved a search of available literature relating to criteria and
noncriteria pollutant emissions associated with secondary aluminum production. This search
included, but was not limited to, the following references:
1)	AP-42 background files maintained by the Emission Factor and Methodologies Section. This
is the source of the six air tests that are reviewed below.
2)	Files maintained by the Emission Standards Division. Although no files are available at this
time, the ESD is currently collecting emission rates from the individual corporations that
comprise the secondary aluminum industry. This information may be available by the end of
1992.
3)	"PM10 Emission Factor Listing Developed by Technology Transfer" (EPA-450/4-89-022).
Reviewed but not used due to uncertain quality of data.
4)	Background Information Documents for NSPS and NESHAPS. No emission source tests
included in the documents reviewed.
5)	Information in the Air Facility Subsystems (AFS) of the EPA Aerometric Information
Retrieval System (AIRS). Three and a half boxes of computer printouts were reviewed. PES
was unable to retrieve any useful information for this application.
6)	Handbook of Emission Factors, Parts I and II, Ministry of Health and Environmental
Protection, The Netherlands, 1980/1983. This information substantiated existing AP-42
Section information. No actual emission test data available.
7)	The EPA Clearinghouse for Inventories and Emission Factors (CHIEF). CHIEF
referenced emission source data as coming from AP-42. No new information.
8)	The EPA databases, including Speciation Database Management System (SPECIATE), the
Crosswalk/Air Toxic Emission Factor Data Base Management System (XATEF). Both of
these database systems were reviewed without tangible benefits.
9)	A literature search was conducted in the Duke University library, including a computer
network search of the University of North Carolina and the North Carolina State University.
In addition, the USEPA Environmental Research Center library was visited in an attempt to
19

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get primary emission source tests for secondary aluminum facilities. No primary emission
source tests for secondary aluminum were found.
To reduce the amount of literature collected to a final group of references pertinent to this
report, the following general criteria were used:
1.	Emissions data must be from a primary reference, i.e. the document must constitute the
original source of test data. For example, a technical paper was not included if the
original study was contained in the previous document.
2.	The referenced study must contain test results based on more than one test run.
3.	The report must contain sufficient data to evaluate the testing procedures and source
operating conditions.
If no primary data was found and the previous update utilized secondary data, this
secondary data was still used and the Emission Factor Rating lowered. A final set of reference
materials was compiled after a thorough review of the pertinent reports, documents, and
information according to these criteria. The final set of reference materials is given in Chapter 4.0.
3.2	EMISSION DATA QUALITY RATING SYSTEM
As part of Pacific Environmental Services' analysis of the emission data, the quantity and
quality of the information contained in the final set of reference documents were evaluated. The
following data were always excluded from consideration.
1.	Test series averages reported in units that cannot be converted to the selected reporting
units;
2.	Test series representing incompatible test methods (i.e., comparison of the EPA
Method 5 front-half with the EPA Method 5 front- and back-half);
3.	Test series of controlled emissions for which the control device is not specified;
4.	Test series in which the source process is not clearly identified and described; and
5.	Test series in which it is not clear whether the emissions were measured before or after
the control device.
20

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Data sets that were not excluded were assigned equality rating. The rating system used was
that specified by the OAQPS for the preparation of AP-42 sections. The data were rated as
follows:
A
Multiple tests performed on the same source using sound methodology and reported in
enough detail for adequate validation. These tests do not necessarily conform to the
methodology specified in either the inhalable particulate (IP) protocol documents or the EPA
reference test methods, although these documents and methods were certainly used as a
guide for the methodology actually used.
B
Tests that were performed by a generally sound methodology but lack enough detail for
adequate validation.
C
Tests that were based on an untested or new methodology or that lacked a significant
amount of background data.
D
Tests that were based on a generally unacceptable method but may provide an order-of-
magnitude value for the source.
The following criteria were used to evaluate source test reports for sound methodology and
adequate detail:
1.	Source operation. The manner in which the source was operated is well documented In
the report. The source was operating within typical parameters during the test.
2.	Sampling procedures. The sampling procedures conformed to a generally acceptable
methodology. If actual procedures deviated from accepted methods, the deviations are
well documented. When this occurred, an evaluation was made of the extent such
alternative procedures could influence the test results.
3.	Sampling and process data. Adequate sampling and process data are documented in the
report. Many variations can occur unnoticed and without warning during testing. Such
variations can induce wide deviations in sampling results. If a large spread between test
21

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results cannot be explained by information contained in the test report, the data are
suspect and were given a lower rating.
4. Analysis and calculations. The test reports contain original raw data sheets. The
nomenclature and equations used were compared to those (if any) specified by the EPA
to establish equivalency. The depth of review of the calculations was dictated by the
reviewer's confidence in the ability and conscientiousness of the tester, which in turn
was based on factors such as consistency of results and completeness of other areas of
the test report.
3.3	EMISSION FACTOR QUALITY RATING SYSTEM
The quality of the emission factors developed from analysis of the test data was rated
utilizing the following general criteria:
A (Excellent)
Developed only from A-rated test data taken from many randomly chosen facilities in the
industry population. The source category is specific enough so that variability within the
source category population may be minimized.
B (Above average)
Developed only from A-rated test data from a reasonable number of facilities. Although no
specific bias is evident, it is not clear if the facilities tested represent a random sample of the
industries. As in the A-rating, the source category is specific enough so that variability
within the source category population may be minimized.
C (Average)
Developed only from A- and B-rated test data from a reasonable number of facilities.
Although no specific bias is evident, it is not clear if the facilities tested represent a random
sample of the industry. As in the A-rating, the source category is specific enough so that
variability within the source category population may be minimized.
D (Below average)
The emission factor was developed only from A- and B-rated test data from a small number
of facilities, and there is reason to suspect that these facilities do not represent a random
sample of the industry. There also may be evidence of variability within the source category
22

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population. Limitations on the use of the emission factor are noted in the emission factor
table.
E (Poor)
The emission factor was developed from C- and D-rated test data, and there is reason to
suspect that the facilities tested do not represent a random sample of the industry. There also
may be evidence of variability within the source category population. Limitations on the use
of these factors are always noted.
The use of these criteria is somewhat subjective and depends to an extent on the individual
reviewer.
23

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3.4	REFERENCES FOR CHAPTER 3
1.	Technical Procedures for Developing AP-42 Emission Factors and Preparing AP-42
Sections. U.S. Environmental Protection Agency, Emissions Inventory Branch, Office of
Air Quality Planning and Standards, Research Triangle Park, NC, 27711, April, 1992.
[Note: this document is currently being revised at the time of this printing.]
2.	AP-42. Supplement A, Appendix C.2, "Generalized Particle Size Distributions." U.S.
Environmental Protection Agency, October, 1986.
24

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4.0
POLLUTANT EMISSION FACTOR DEVELOPMENT
4.1	CRITERIA POLLUTANT EMISSIONS DATA
No source test data, fulfilling the requirements of Sections 3.1 and 3.2 on emissions of
volatile organic compounds, lead, sulfur dioxide and nitrogen oxides were found for the secondary
aluminum industry.
Carbon monoxide.
During September 1990 at State Metal Industries, Inc., compliance emission tests were
conducted on a fabric filter serving as a pollution control device for charging wells on three
aluminum scrap smelting furnaces, and each of the three independent uncontrolled smelting furnace
burner exhaust flues (one for each furnace). These compliance tests are "A" rated and listed as
reference 7 for this chapter. Listed below are the carbon monoxide emission rates from each
smelting furnace burner flue. PES believes many more carbon monoxide tests of randomly chosen
smelting furnace burners is appropriate prior to being reported in Section 7-8. This belief is based
on the variation in emissions that occur during batch operations associated with most secondary
smelting operations.
25

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TABLE 4.1-1 (METRIC UNITS)
CARBON MONOXIDE
Control
Equipment
Test
Rating
Test
Method
Run
#
Production
Rate1
Emission
Rateb
Emission
Factor0
1. Plibric
o Flued





None
A

1
2.08
0.054
0.026
2
2.06
0.145
0.071
3
2.08
0.200
0.096
Averag
e
2.07
0.135
0.064
2. North American Flued
None
A

1
0.3
0.018
0.061
2
0.3
0.023
0.076
3
0.3
0.027
0.091
Averag
e
0.3
0.023
0.068
3. United Flued
None
A

1
.72
0.145
0.203
2
.72
0.086
0.121
3
.72
0.091
0.127
Averag
e
.72
0.104
0.150
aUnits in Mg/hr.
bUnits in kg/hr.
cUnits in kg/Mg.
d
Analysis utilized nondispersal infrared techniques. Samples were collected in 80-liter Tedlar bags
at a rate of 0.5 to 0.81 per minute. The measurement instrument was calibrated with EPA
Protocol-1 CO standards.
26

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TABLE 4.1-1 (ENGLISH UNITS)
CARBON MONOXIDE
Source
Test #
Test
Rating
Test
Method
Run
#
Production
Rate1
Emission
Rateb
Emission
Factor0
1. Plihn
ico Flued





None
A

1
2.29
0.12
0.052
2
2.27
0.32
0.141
3
2.29
0.44
0.192
Averag
e
2.28
0.29
0.128
2. North American Flued
None
American
Flued
A

1
.33
0.04
0.121
2
.33
0.05
0.152
3
.33
0.06
0.182
Averag
e
.33
0.05
0.152
3. United Flued
None
A

1
.79
0.32
0.405
2
.79
0.19
0.241
3
.79
0.20
0.253
Averag
e
.79
0.23
0.300
TJnits in ton/hr.
bUnits in lb/hr.
cUnits in lb/ton.
d
Analysis utilized nondispersal infrared techniques. Samples were collected in 80-liter Tedlar bags
at a rate of 0.5 to 0.81 per minute. The measurement instrument was calibrated with EPA
Protocol-1 CO standards.
27

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Total Suspended Particulate & PM,,..
PM10 is a subset of total suspended particulate (TSP) and consists of particles having a
diameter of less than ten microns ((jm). There is no single method which is universally accepted for
the determination of particle size. A number of different techniques can be used which measure the
size of particles according to their basic physical properties. Since there is no "standard" method
for particle size analysis, a certain degree of subjective evaluation was used to determine if a test
series was performed using a sound methodology for particle sizing.
For pollution studies, the most common types of particle sizing instruments are cyclones,
rotoclones, and cascade impactors. Traditionally, cyclones and rotoclones have been used as a
preseparator ahead of a cascade impactor to remove the larger particles. These devices are of the
standard reverse-flow design whereby the flue gas enters the cyclone through a tangential inlet and
forms a vortex flow pattern. Particles move outward toward the cyclone wall with a velocity that is
determined by the geometry and flow rate in the cyclone and by their size. Large particles reach the
wall and are collected. A series of cyclones with progressively decreasing cut-points can be used to
obtain particle size distributions.
Cascade impactors used for the determination of particle size in process streams consist of a
series of plates or stages containing either small holes or slits with the size of the openings
decreasing from one plate to the next. In each stage of an impactor, the gas stream passes through
the orifice or slit to form a jet directed toward an impaction plate. For each stage, there is a
characteristic particle diameter that has a 50 percent probability of impaction. This characteristic
diameter is called the cut-point (D50) of the stage. Typically, commercial instruments have six to
eight impaction stages with a backup filter to collect those particles which are either too small to be
collected by the last stage or which are re-entrained off the various impaction surfaces by the
moving gas stream.
The tables listed below reflect controlled particulate from a fabric filter that is the control
device for charging wells serving three independent smelting furnaces, and the uncontrolled
particulate emissions from each of three separate smelting furnace burner flues. The source test
used to build these tables is a compliance emission test at State Metal Industries, Inc., during
September 1990. The test data is an "A" rated test and is listed as reference 7. Pacific
Environmental Services did not add this information to Section 7-8 because the data represents
28

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only one company's operation and variations in emission rates reflect the batch operation normally
found in secondary aluminum smelting facilities. Additional random testing at other facilities needs
to be conducted in order to establish a more reliable emission factor.
29

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TABLE 4.1-2 (METRIC UNITS)
TOTAL SUSPENDED PARTICULATE AND PM10
Control
Equipment
Test
Rating
Test
Method
Run
#
Production
Rate1
Emission
Rateb
Emission
Factor0
1. (For 3
charging w
ells)d




Fabric filter
A
5
1
3.12
0.717
0.230
2
3.11
0.229
0.074
3
3.10
0.087
0.028
Averag
e
3.11
0.341
0.110
2. Plibrico Burner Flued
None
A
5
1
2.08
1.773
0.854
2
2.06
0.139
0.067
3
2.08
0.106
0.051
Averag
e
2.07
0.564
0.494
3. North American Burner Flued
None
A
5
1
0.30
0.024
0.082
2
0.30
0.018
0.060
3
0.30
0.020
0.068
Averag
e
0.30
0.020
0.070
4. United Flued
None
A
5
1
0.72
0.380
0.529
2
0.72
0.115
0.160
3
0.72
0.178
0.248
Averag
e
0.72
0.224
0.312
aUnits in kg/hr.
bUnits in kg/Mg.
cUnits in kg/Mg.
d
Analysis utilized nondispersal infrared techniques. Samples were collected in 80-liter Tedlar bags
at a rate of 0.5 to 0.81 per minute. The measurement instrument was calibrated with EPA
Protocol-1 CO standards.
30

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TABLE 4.1-2 (ENGLISH UNITS)
TOTAL SUSPENDED PARTICULATE AND PM10
Control
Equipment
Test
Rating
Test
Method
Run
#
Production
Rate1
Emission
Rateb
Emission
Factor0
1. (For 3
charging w
ells)d




Fabric filter
A
5
1
3.44
1.58
0.459
2
3.43
0.504
0.147
3
3.42
0.192
0.056
Averag
e
3.43
0.752
0.219
2. Plibrico Burner Flued
None
A
5
1
2.29
3.91
1.707
2
2.27
0.306
0.134
3
2.29
0.234
0.102
Averag
e
2.28
1.243
0.545
3. North American Burner Flued
None
A
5
1
.325
0.053
0.163
2
.325
0.039
0.120
3
.325
0.044
0.135
Averag
e
.325
0.045
0.139
4. United Flued
None
A
5
1
0.793
0.838
1.057
2
0.793
0.254
0.320
3
0.793
0.393
0.496
Averag
e
0.793
0.495
0.624
aUnits in lb/hr.
bUnits in lb/ton.
cUnits in lb/ton.
d
Analysis utilized nondispersal infrared techniques. Samples were collected in 80-liter Tedlar bags
at a rate of 0.5 to 0.81 per minute. The measurement instrument was calibrated with EPA
Protocol-1 CO standards.
31

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4.2	NONCRITERIA POLLUTION EMISSION DATA
Hazardous Air Pollutants.
Hazardous Air Pollutants (HAPs) are defined in the 1990 Clean Air Act Amendments. No
source test data fulfilling the requirements of Sections 3.1 and 3.2 for HAPs were found for the
secondary aluminum industry.
Global Warming Gases.
Pollutants such as methane, carbon dioxide, and N20 have been found to contribute to
overall global warming. No source test data fulfilling the requirements of Sections 3.1 and 3.2 for
methane, carbon dioxide, and N20 were found for the secondary aluminum industry.
Ozone Depletion Gases.
Chlorofluorocarbons have been found to contribute to ozone depletion. No source test data,
fulfilling the requirements of Sections 3.1 and 3.2 for chlorofluorocarbons were found for the
secondary aluminum industry.
4.3	REVIEW OF SPECIFIC DATA SETS
Pacific Environmental Services lowered all the emission factors in Table 2.3-1 and Table
2.3-2 to "E" to reflect the reference sources used to build emission rates in the tables. Table 2.3-1
is based upon an unpublished report on contaminates written in July, 1964. Another Table 2.3-1
footnote describing tabulated emission rates as being the average of ten unidentified source tests.
Table 2.3-2 references AP-40 and the Environmental Assessment Data System as the emission rate
sources. In accordance with guidance found in Chapter 3, PES believes it is justified in lowering
the emission factor.
The following air source tests were reviewed by PES for possible use in Section 7-8 of AP-
42. Each source is identified and technical problems discovered during the review are discussed.
Only one of the six tests contained data judged to be accurate.
32

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L. Rochester Smelting and Refining Company: October 22. 1976
Coated Baghouse: control of emissions from charging and demagging operations from
secondary aluminum. Smelter work completed on 10/22/76.
This emission test was reviewed by PES and not found acceptable for inclusion because of
radically fluctuating baghouse efficiency data. In addition, daily production information had been
averaged from three smelting furnaces operating during the day and two operating at night. The
baghouse outlet probe was not heated as required by Method 5 during the night collection period.
Chlorine measurements were made over a full particulate collection period, and a second run after
all demagging had been completed. Of five test runs, only three of the five samples were collected
simultaneously. There were also no field notes, equipment calibration documentation, and no real-
time production activity related to emission data. (Reference 2).
2± Vista Metals Corporation: September 1981
A scrubber is used to capture chlorine and chlorine compounds from submerged chlorinator
section of smelting furnace. Tests also includes particle size distribution at scrubber inlet.
This is an excellent source test for what is believed to be a unique chlorine/chloride control
system consisting of a submerged furnace vapor capture area, a settling chamber and scrubber.
PES believes the chlorine/chloride values are accurate, but because of the uniqueness of the
system, that data is not incorporated into the Section or this background report. A copy of the
report is available in the US EPA files at Research Triangle Park, NC as EMB Report 80-GAL-2
of August 1981. (Reference 3).
3^ North American Smelting Company: January 1981
This source test was designed to evaluate stack sampling techniques for secondary
aluminum. The outlets from a coated baghouse for a charging well and an outlet from a high
pressure venturi chlorination scrubber were tested. Production information along with control inlet
data was not included in the testing, so this source test is not incorporated into this report.
(Reference 4).
33

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£L Barnet Industries: April 1978
Dross recovery rotary furnaces with baghouse control.
Available documentation is not enough to document a reliable emission test rating or
emission factor. (Reference 5).
y Hall Aluminum Company: October 1979
This is a compliance test, measuring emissions downstream from an afterburner controlling
a rotary dryer.
The test results showed compliance, but did not include the elements of a source test needed
for AP-42 source tests. (Reference 6).
State Metal Industries. Inc.: September 1990
Compliance emission tests on a fabric filter serving as control for the charging wells of three
aluminum scrap smelting furnaces, and compliance testing each of the three independent
uncontrolled smelting furnace burner exhaust flues (one for each furnace). The fabric filter
emission was tested for particulate, hydrochloric acid and chlorine. Each smelting furnace burner
exhaust flue was tested for nitrogen oxide, total hydrocarbons, carbon monoxide and particulate.
The testing results for hydrochloric acid and chlorine is not used in this chapter because chlorine
emission is normally based upon free chlorine, aluminum chloride, magnesium chloride, and
hydrochloric acid. It should be noted that hydrochloric acid could be derived from other sources
unrelated to demagging (i.e., burning PVC pipe in aluminum scrap charged in the smelter). Total
hydrocarbon samples were taken from each smelting burner flue and tested in accordance with the
principles of NJ Air Test Method 3, Section 3-9. Volatile organic compounds in the sample are not
available as no distinction is made between methane and non-methane hydrocarbons. Nitrogen
oxides are not tabulated in this chapter because out of 9 samples taken, only one sample was found
to exceed the method's detectible level (detection level =1.4 mg/sample) with an emission rate of
2.3 lbs/hr. Therefore, only controlled particulate emission rates (after the fabric filter) and
uncontrolled particulate and carbon monoxide emission rate from each smelting furnace burner flue
are included in chapter 4. Despite these limitations, this compliance test is an "A" rated test
provided by the State of New Jersey. (Reference 7).
34

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4.4	DATA GAP ANALYSIS
Available data for emissions for secondary aluminum industry processes have emission
factor ratings of E. The emission factor is a measure of the confidence level that can be attached to
the reported emission values. The low emission factor ratings are dictated by a deficiency of
quality source tests with accurate production rates that meet the stringent quality control
requirements discussed in Chapter 3. However, low emission factor ratings should not be used to
infer that reported emission rates are in error or are of little value. Emission rates reported in
Chapter 2 are the best information available at this time.
Secondary aluminum emissions are greatly influenced by the quality of scrap metals
processed (the amount of contaminates such as oil, paint, dirt and non- aluminum metals). There
are 116 secondary aluminum recovery facilities in the U.S., each with one or more scrap sources.
Each scrap source may supply multiple scrap streams with varying degrees of contamination and
nonaluminum metal mix. As a result, not only can emissions from similar secondary aluminum
recovery facilities vary, but emissions from an individual plant can vary from day to day depending
on the mix of scrap. The quality of scrap being charged during emission testing should be
monitored and reported as one of the classifications needed when tabulating emissions from the
secondary aluminum industry.
General secondary aluminum plant emissions have been found to include HAPs such as
antimony, cobalt, selenium, cadmium, and arsenic. These elements and their compounds need to be
tested for to establish their emission rates.
In order to assign importance related to future source testing, the following prioritized list
for testing is based upon both quantity and the constituents found in uncontrolled emissions that
have been reported in earlier emission studies. The list includes production equipment that
generates the emission, the emissions generated and pollution equipment normally used to control
that emission. In order to maximize testing resource, reverberatory furnaces should be tested first.
Reverberatory furnaces,
burning and drying operations,
UBC delacquering systems,
rotating barrel dross furnaces,
sweating furnaces,
dry milling and leaching operations
35

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and scrap pretreatment emissions.

-------
TABLE 4-4.
LIST OF CONVERSION FACTORS
Multiply:
by:
To obtain:
mg/dscm
4.37 x 10"4
gr/dscf
m2
10.764
ft2
acm/min
35.31
acfm
m/s
3.281
ft/s
kg/hr
2.205
lb/hr
kPa
1.45 x 101
psia
kg/Mg
2.0
lb/ton
Mg
1.1023
ton
Temperature conversion equations:
Fahrenheit to Celsius:
oC = CF-32)
1.8
Celsius to Fahrenheit:
°F = 1.8(°C) + 32
37

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4.5	REFERENCES FOR CHAPTER 4
1.	Technical Procedures for Developing AP-42 Emission Factors and Preparing AP-42
Sections. U.S. Environmental Protection Agency, Emissions Inventory Branch, Office of
Air Quality Planning and Standards, Research Triangle Park, NC, 27711, April, 1992.
[Note: this document is currently being revised at the time of this printing.]
2.	Rochester Smelting and Refining Company. October 22. 1976. U.S EPA, Office of Air
Quality, Research Triangle Park, NC 27711.
3.	Vista Metals Corporation - September 1981. EMB Report 80-SAL-2 August 1981, U.S
EPA, Office of Air Quality Planning and Standards, Research Triangle Park, NC 27711.
4.	North American Smelting Company. January 1981. Contract No. 68-02-2815, U.S. EPA,
Emission Measurement Branch, Research Triangle Park, NC 27711.
5.	Barnet Industries - April 1978. U.S EPA, Office of Air Quality, Research Triangle Park,
NC 27711.
6.	Hall Aluminum Company. October 1979. U.S EPA, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711.
7.	State Metal Industries. Inc. September 1990. U.S EPA, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711.
38

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