SPA-450/3-74-012
[ay 1973
NATIONAL EMISSIONS
INVENTORY
OF SOURCES
AND EMISSIONS
OF
CHROMIUM
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Water Programs
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
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EPA-450/3-74-012
NATIONAL EMISSIONS INVENTORY
OF
SOURCES AND EMISSIONS
OF
CHROMIUM
by
GCA Corporation
GCA Technology Division
Bedford, Massachusetts 01730
Contract No. 68-02-9601
EPA Project Officer: David Anderson
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Water Programs
Office of Air Quality Planning and Standards
Research Triangle Park, N. C. 27711
May 1973
-------
This report is issued by the Environmental Protection Agency to report technical
data of interest to a limited number of readers. Copies are available free of
charge to Federal employees, current contractors and grantees, and nonprofit
organizations - as supplies permit - from the Air Pollution Technical Information
Center, Environmental Protection Agency, Research Triangle Park, North
Carolina 27711, or from the National Technical Information Service, 5285 Port
Royal Road, Springfield, Virginia 22151.
This report was furnished to the Environmental Protection Agency by GCA Corp-
oration, Bedford, Massachusetts, in fulfillment of Contract No. 68-02-9601. The
contents of this report are reproduced herein as received from GCA Corporation.
The opinions, findings, and conclusions expressed are those of the author
and not necessarily those of the Environmental Protection Agency. Mention of
company or product names is not to be considered as an endorsement by the
Environmental Protection Agency.
Publication No. EPA-450/3-74-012
11
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ABSTRACT
A national inventory of the sources and emissions of the element
chromium was conducted. The study included the preparation of an over-
all material flow chart depicting the quantities of chromium moving
from sources of mining and importation through all processing and repro-
cessing steps to ultimate use and final disposition. All major sources
of chromium-containing emissions were identified and their chromium
emissions into the atmosphere estimated. A regional breakdown of these
sources and their emissions was also provided. The physical and chemi-
cal nature of the chromium-containing emissions was delineated to the
extent that information was available, and a methodology was recommended
for updating the results of the study every 2 years.
Ill
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ACKNOWLEDGEMENT
The continued cooperation and dedication of Mr. Carl Spangler of
EPA, who served as Program Monitor until his death, is deeply appreci-
ated.
GCA would like to extend thanks to Mr. David Anderson and
Mr. James Southerland of EPA for their cooperation in the prep-
aration of this study.
In addition, special thanks are also due to Mr. John Morning,
Commodity Specialist, Bureau of Mines, who provided significant tech-
nical inputs to this program.
IV
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TABLE OF CONTENTS
SECTION TITLE PAGE
I . INTRODUCTION 1
A. PURPOSE AND SCOPE 1
B. CONCLUSIONS 2
II OVERALL U.S. MATERIAL FLOW CHART FOR
CHROMIUM 5
A. U.S. PRODUCTION AND ORE PROCESSING 5
B. IMPORTS OF CHROMIUM-CONTAINING ORE 5
C. GOVERNMENT AND INDUSTRIAL STOCKPILE
CHANGES 5
D. EXPORTS AND RE-EXPORTS OF CHROMITE 6
E. CONSUMPTION 6
III SOURCES AND ESTIMATES OF CHROMIUM-CON-
TAINING EMISSIONS 8
A. DATA PRESENTATION AND ACCURACY 8
B. DEVELOPMENT OF EMISSIONS ESTIMATES - 1970 11
C. SUMMARY OF PRINCIPAL EMISSIONS 19
IV REGIONAL DISTRIBUTION OF PRINCIPAL SOURCES
AND EMISSIONS 21
V NATURE OF EMISSIONS 25
A. FERROCHROMIUM PRODUCTION EMISSIONS 25
B. REFRACTORY PRODUCTION EMISSIONS 26
C. CHROME STEEL PRODUCTION EMISSIONS 27
D. COAL COMBUSTION EMISSIONS 27
E. OIL COMBUSTION EMISSIONS 27
F. CEMENT PRODUCTION EMISSIONS 28
G. AMBIENT CHROMIUM AND TOXICITY 28
VI UPDATING OF EMISSIONS ESTIMATES 29
A. VERIFICATION OF CURRENT ESTIMATES 29
B. PERIODIC REVIEW OF ESTIMATES 29
VII REFERENCES 31
V
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LIST OF TABLES AND FIGURES
TABLE NO.
TITLE
PAGE
NATIONAL STOCKPILE ORE-PURCHASE
SPECIFICATIONS (Weight-percent,
dry basis)
SOURCES AND ESTIMATES OF CHROMIUM-
CONTAINING EMISSIONS
SUMMARY OF PRINCIPAL SOURCES AND
EMISSIONS OF CHROMIUM
REGIONAL DISTRIBUTION OF PRINCIPAL
SOURCES AND EMISSIONS
SOME PHYSICAL PROPERTIES OF CHROMIUM
AND ITS COMPOUNDS
12
20
22
25
FIGURE NO.
CHROMIUM MATERIAL FLOW - 1970
VI
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I. INTRODUCTION
A. PURPOSE AND SCOPE
The Monitoring and Data Analysis Division, Office of Air
Quality Planning and Standards of the U.S. Environmental Protection
Agency (EPA) has contracted with GCA Technology Division to conduct a
national inventory of the sources and emissions of the element chrom-
ium. The purpose of the study was to define as accurately as possible,
based on existing and available published and unpublished information,
the levels, nature and sources of chromium-containing emissions for de-
fined geographic regions throughout the United States.
The scope of this program is outlined below:
. Develop an overall material flow chart
depicting the quantities of chromium
moving from sources of mining and impor-
tation, through all processing and re-
processing steps, to ultimate use and
final disposition as far as the move-
ments can be traced.
. Identify all major potential chromium-
containing emission sources and estimate
the total quantity of chromium emitted
to the atmosphere from each source. Emis-
sion factors and level and types of air
pollution control will also be provided
for each of these sources to the extent
that available information permits.
. Define those sources which contribute at
least 80 percent of the total emissions
of chromium.
. Provide a regional breakdown of these
major sources and their emissions.
. Present the nature of the chromium-
containing emissions for each of these
major sources including a delineation of
their physical and chemical forms and
particle size distribution to the extent
that information is available.
. Provide recommendations as to a methodology
for updating the results of this study
every 2 years.
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B. CONCLUSIONS
1. Material Flow
Based on all available data, 428,000 tons of chromium in
ore form was consumed in the U.S. in 1970. As shown in Figure 1, this
was nearly all new material with very little scrap being recycled. All
new material was imported, there being no domestic mining of chromium
ore.
Nearly all the chromium was used for metallurgical pro-
ducts, chiefly ferrochromium and subsequently for stainless and other
grades of steel containing chromium.
Certain assumptions made in preparing the above estimates,
due to a deficiency of data in certain areas, are explained in detail
in Section II.
2. Principal Emission Sources
Just over one half of the total estimated U.S. atmospheric
emissions of chromium are estimated to be from ferrochromium production.
Another 20 percent results from the production of refractory materials
and chromium steels. About 20 percent results from processes outside
the chromium industry, including the combustion of coal and oil, and
the production of cement.
3. Regional Estimates
The region of the U.S. in which most of the chromium is
estimated to be emitted is Regions* (Ohio and vicinity). Region 2 (New
York and New Jersey) is estimated to contain the largest total emission
of chromium per average square mile. These findings are partly weighted
by the emissions from ferrochromium production, which are substantial in
both of these regions.
4. Nature of Emissions
Based on the principal emitting processes, most of the
chromium is estimated to be emitted in micrometer-sized particles
*See page 21 for a list of regions.
2
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CoMuapt Ion
mat 'or
Proc *••!(«
fturUl
J
residue
rat lea
Figure 1. Chromium 1970 material flow
(Thousand Short Tons contained Cr)
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and smaller. The chemical forms of the emissions from these processes
are not established, although some forms are stated in the literature
to be toxic.
5. Degree of Control
The overall level of control of chromium emission is es-
timated to have been about 54 percent in 1970. The estimated degree
of control would have been greater, but for the relatively low control
of ferrochromium processes estimated at 40 percent in 1970. More re-
cent reports in 1973 indicate, however, that a 76 percent degree of
control has been achieved in the ferrochromium industry, resulting in
a current overall level of control of 72 percent.
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II. OVERALL U.S. MATERIAL FLOW CHART FOR CHROMIUM
Figure 1* presents a flow diagram depicting the total quantities
of chromium products moving from sources of mining and importation
through the processing and reprocessing steps to ultimate use and final
disposition. Each of these sources is discussed below.
A. U.S. PRODUCTION AND ORE PROCESSING
There has been no mining or ore processing of chromite in the
U.S. since 1961 when the Government's Defense Production Act sponsor-
ship was phased out. There are known deposits of possible future
commercial value in the northwest and Alaska, the largest being the
Stillwater Complex in Montana.
B. IMPORTS OF CHROMIUM-CONTAINING ORE
Total imports of chromite in 1970 totaled 1,405,000 short
(2\
tons. ' The total Cr^O- content of the ore varies, depending on con-
sumption usage of the ore, from 30 to 50 percent. The total Cr90, con-
/2) J
tent of the ore was 647,000 short tonsv averaging 46 percent. Based
on chromium content in CrJD, of 68 percent by weight, 443,000 tons of
chromium in ore form was imported in 1970.
C. GOVERNMENT AND INDUSTRIAL STOCKPILE CHANGES
Due to the politically unstable nature of the supply of
chromium ore, stockpiles tend to be larger than ordinarily expected;
hence, shifts in stockpiles must also be considered to justify consump-
tion figures. The National Stockpile re-evaluated its needs and re-
duced its inventories of chromium in 1970 by an estimated 44,000 tons
of contained chromium.
Industrial stocks rose in the metallurgical industry, dropped
in the chemical industry and remained relatively constant in the
Data in Figure 1 and in this section are left rounded, for purposes
of information control. On average, the typical statistic is accur-
ate to within 10 percent, in the opinion of the authors.
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refractory industry resulting in a net increase of 69,000 short tons of
(2)
chromite ore stocks containing 23,000 tons of chromium.
D. EXPORTS AND RE-EXPORTS OF CHROMITE
Exports and re-exports of ore have been primarily for the
production of chromite based in Canadian or South American plants owned
by U.S. firms. ' There is little processing of this ore except per-
(2)
haps some finer crushing. In 1970, 114,000 tons were exportedv ' with
a chromium content of 36,000 tons.
E. CONSUMPTION
Chromite ore is classified into three major categories based
on its composition. Table 1 contains the National Stockpile specifi-
cations for stockpile grade ore. Based on chromium content, 70 percent
of the ore in 1970 was consumed by the metallurgical industry, 16 per-
cent by the refractory industry, and 14 percent by the chemical indus-
try.
TABLE 1
NATIONAL STOCKPILE ORE-PURCHASE SPECIFICATIONS
(Weight-percent, dry basis)
Grade
Metallurgical
Refractory
Chemical
Cr: Fe
Ratio
Mini-
mum
3.1
Cr203
Mini-
mum
48.0
31.0
44.0
Fe
Maxi-
mum
12.0
Cr203
A1203
Mini-
mum
58.0
Si02
Maxi-
mum
8.0
6.0
5.0
S
Maxi-
mum
0.08
P
Maxi-
mum
0.04
CaO
Maxi-
mum
1.0
1. Metalurgical Industry
Chromite ore of metallurgical grade is converted entirely
to various grades of ferrochromium and to chromium additives and metal.
Metallurgical consumption of goods totaled 300,000 tons of contained
(2)
chromium of which 290,000 tons, or 96 percent was in ferrochromium.
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2. Refractory Industry
The refractory industry is a major consumer of chromite
ore using it in the production of chrome brick, chrome-magnesite brick
and magnesite-chrome brick. Chrome ore is also used as patching mater-
ial for refractories. Consumption totaled 278,000 short tons of chro-
(2)
mite containing 67,000 tons of chromium.
3. Chemical Industry
Chemical processing of chromite ore into various indus-
trial chemicals proceeds from sodium dichromate or sodium chromate
which are the primary products. The chromate chemical industry is ex-
tremely vertically integrated and four processing plants produce all
the chromium containing chemicals in the country.
The chemical industry consumed 213,000 fcon^ of chromite
ore containing 61,000 tons of chromium to produce 148,000 t;ons of
chemicals (sodium dichromate equivalent). These chemicals were consumed
in a host of industries. Metal plating, paints and pigments, and
leather tanning were the predominant uses, cpnsuming about 6Q percent
of the total chromium used by the chemical industry.
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III. SOURCES AND ESTIMATES OF CHROMIUM-CONTAINING EMISSIONS
A. DATA PRESENTATION AND ACCURACY
Table 2 presents a summary of the data from which emissions
were estimated for all major potential sources. Each of the col-
umns comprising this table will be discussed below.
1. Emission Factors
Except where indicated, this gives the pounds of total
particulate emitted per ton of production. Such considerations as:
. variations in process conditions
among individual plants comprising
a source category
. inaccuracies in existing data
. a limited quantity of existing data,
may, however, result in an average emission factor for a source cate-
gory varying by more than an order of magnitude from the value pre-
sented. In recognizing the need to indicate the level of accuracy of
these emissions factors, a reliability code is presented along with
each emission factor value appearing in the table. This reliability
code system is described below and is based on the system utilized in
(4)
EPA Document No. AP-42, "Compilation of Air Pollutant Emission Factors":
A: Excellent
This value is based on field measure-
ments of a large number of sources.
B: Above Average
This value is based on a limited number
of field measurements.
C: Average
This value is based on limited data
and/or published emission factors where
the accuracy is not stated.
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D: Below Average
This emission factor is based on
engineering estimates made by know-
ledgeable personnel.
2. Level of Production Activity
This column depicts the quantity of material produced
(unless otherwise stated)' annually. When multiplied by the emission
factor, an estimate of the total particulate emissions for that source
in pounds per year is obtained.
The values in this column are based on the material, flow
calculations presented in Section II. Consequently, they have the same
accuracy as those material flow values which is estimated at + 10 per-
cent.
3. Percent Metal in Emissions
The method of analyzing or assaying a dust sample for the
amount of metal it contains determines to a large extent the reliabil-
ity of the data. For example, analytical chemistry techniques for dust
containing substantial fractions of metal can be accurate to within a
small percentage. On the other hand, optical spectroscopy methods for
determining concentrations on the order of parts per million can be in-
accurate by a factor of 2. Because of this variability, the reliabil-
ity codes discussed above for the emission factors are also utilized
to estimate the relative accuracy of the percentage values listed in
this column.
4. Level of Chromium Emissions Before Control
The values in this column are derived by multiplying the
values in columns 1 through 3. The result is converted to tons/year
of emissions before control.
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5. Estimated Level of Emission Control
The overall effectiveness of control for a source cate-
gory is based on two factors:
. the portion of the processes which
are under control
. the typical degree of control
For example, if 60 percent of vertical roasters have some type of par-
ticulate emission control, and these include both scrubbers and pre-
cipitators such that the apparent weighted average efficiency of con-
trol is 85 percent, the overall control effectiveness is estimated to
be 60x85 = 51 percent.
The accuracy of control efficiency data varies with the
degree of control. For a wet scrubber operating at 80 percent effi-
ciency; i.e., passing 20 percent material, the actual emission may
safely be assumed to be between 15 and 25 percent because of the rela-
tive ease of making determinations at this level. Thus the emissions
after control may be assumed to accurate within + 5/20 or 25 percent.
On the other hand, for a baghouse reported as being 99 percent effi-
cient, or passing only 1 percent of the material, the actual emission
may vary from 0.5 percent to perhaps 2 percent because it is frequent-
ly difficult to make low-level measurements with accuracy. In such
case, the resulting emission data could be in error by a factor of 2.
Unless otherwise specified, it is assumed that the re-
ported overall level of particulate control applies equally to all
chromium-containing particles, independent of size, resistance, and
other important collection parameters. This assumption results in a
correct estimate of chromium emissions after control when the particu-
late is chemically homogeneous; i.e., the chromium is contained in the
same concentration in all particles. If however, chromium is concen-
trated in certain particles and in addition, the efficiency of the con-
trol equipment is not uniform for all particles, then the utilization
of an average control level is less valid for calculating chromium
10
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emissions after control. Data on the preferential control of chromium-
containing particles is seldom available, but is included in this re-
port when possible.
The accuracy of estimating the level of control for a
specific source category is dependent on the quality of available data.
The investigators feel that, in general, the level of control data will
contribute an accuracy to the resulting emissions estimates within + 25
percent.
6. Level of Metal Emissions After Control
The values in this column are derived by multiplying the
values in column 4 by the value (100 minus estimated Level of Control).
B. DEVELOPMENT OF EMISSIONS ESTIMATES - 1970
Estimates of particulate emissions containing chromium in the
U.S. atmosphere are developed in the following paragraphs, and in Table
2. The table indicates that metallurgical and refractory processes
produce most of the emissions, as will be shown.
1. Mining and Ore Processing
There are presently no operating mines for chromium in
the United States. There are various low-grade ore deposits in the
United States predominantly in the Northwest and in Alaska.
2. Metallurgical Processing
The use of chromite ore is divided into three major cate-
gories, the largest of which, metallurgy, accounts for 70 percent of
chromium consumption. The major primary products are various grades
of ferrochromium, ferrochromium-silicon, and chromium metal.
a. Ferrochromium
The production of high carbon ferrochromium involves
smelting of chromite ore with coke, and tapping of the ferrochromium
from the bottom of the furnace. Low carbon ferrochromium can be pro-
duced by the use of quartz in place of coke to form ferrochromium-
11
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-,:^LB 2
SOURCES AND ESTIMATES OF CHROXIUM-CONTAINING EMISSIONS IN 1970
Source
MINING
None in U.S.A.
REFINING
Farrochr outturn:
Electric Furnace
Material Handling
Electrolytic Chromium
REFRACTORY
Non-Cast
Electric Cast
CHEMICAL PROCESSING
Dichr ornate
Other Chemicals
STEEL AND ALLOYS
Chromium Steels
Cast Iron
Super Alloys and
Alloys
General Steel making
INADVERTENT SOURCES
Coal Combustion
Oil Combustion
Cement Production
Incineration
Asbestos
Total
Uncontrolled
Emission
Fac tor
•t
lb/ton kg/10 kg
(200-830)
500"
10
0.048
150
225
30
...
25
75
25
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
(100-415)
250'
5
0.024
75
112 •
15
...
12
38
12
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
Tr
"t V
11
9 U
c
B
C
C
C
C
-
C
c
c
Production
Level
ftons/yr)
375,500
375.500
9,000
60,300
6,700
61,000
...
189,000
5,000
12,000
N.A.
,
33,800.000*
287,000°
934,000e
931,000°
6.579
Percent
Cr In
22
65
51
b
b
b
--
b
b
b
N.A.
0.026
0.13
0.03
0.017
0.15
*•
>H «
as
a u
B
C
A
A
B
C
C
C
Emissions of
Cr Before
Controls
(tons/yr)
0
20,600
1,220
(neg)
4,500
754
920
...
2,362
188
150
N.A.
8,700
370
N.A.
N.A.
10
39,774
Estimated
Level of
Emission
Control
407.
32*
951
641
77X
901
--
781
99X
781
N.A.
821
0
N.A.
N.A.
99*
541
Emissions
of Cr After
Controls
(tons/vr)
0
12,360
830
(neg)
1.630
173
92
24C
520
2
33
iood
1,564
370
280
158
0
18,136
Intermediate value (see text )
Emission factor multiplier equal to tons of Cr processed or handled annually.
See text for explanation.
Tteedi further investigation
Emissions, after control.
Emissions, before control.
N.A. - Not applicable.
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silicon, followed by further smelting with additional chromite. In
every case, ferrochromes are produced in an electric arc furnace. Emis-
sions have previously been estimated at 200 Ib/ton of product, '
based on electric furnace emissions for other than ferrochromium pro-
duction, because no ferrochromium data was available at that time. More
recently, emission factors of 330 Ib/ton of high carbon ferrochromium
and 830 Ib/ton of low carbon ferrochromium or ferrochrome silicone have
been reported based on tests of specific ferrochromium furnaces.
Other data indicate a wide range of emission factors, but lack adequate
process descriptions to make the data useful. '
The overall level of control effectiveness has been
estimated at 40 percent, based on about 50 percent application of ap-
proximately 80 percent control equipment. These estimates were based
on a survey of the ferroalloy industry in 1969-70 (11 companies, 22
(5,8)
(3)
plants, 127 furnaces included in the survey). More recently, re-
ports of a typical 95 percent control efficiency have been reported.
It is estimated that the level of application is now at least 80 per-
cent, giving an overall control effectiveness of about 76 percent at the
present time (1973).
Using a mean emission factor value of 500 Ib/ton, a
40 percent level of control in 1970, and a production level of 375,500
tons of ferrochromium in 1970 results in 56,325 tons of particulate
emissions after control. The fume emitted during ferrochromium produc-
tion is reported to contain 15 to 30 percent chromium, depending on
the type of ferrochrome being produced. An average content of 22
percent is assumed. The resulting estimated emission from ferrochromium
production of all kinds, is 12,360 tons of chromium emitted to the atmo-
sphere .
Further emissions occurred in ferroalloy production
from material handling estimated at 10 Ib/ton of product with a control
(3 4)
of 32 percent. ' Composition of these emissions was estimated to
be equivalent to the amount of chromium in the ferroalloy, about 65
percent. Total emissions are estimated at 830 tons.
13
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b. Chromium Metal
Production of chromium metal is done predominantly by
electroplating of the chromium from a chrome-alum solution. Approxi-
mately 75 percent of the metal or 9,000 tons were produced in this man-
ner. Practically no emissions data were found for chrome plating or
even for electroplating in general. One reference reported that chromic
acid mist from chrome plating was reduced from 42.65 MG/CU M (presumed
milligrams per cubic meter, rather than micrograms) to 0.077 MG/CU M
(9)
by "washing with water." Using an estimated gas release rate of
1000 CU M per ton of metal plated, ' a pre-control emission of 0.094
pounds of acid or 0.048 pounds of chromium per ton of chromium plated,
is obtained. This reference indicates an estimated degree of control
of 95 percent. This results in a negligible level of emissions. The
(9)
form of the chromium, HCrO,,, is toxic. '
The remaining chromium metal is produced by an alumino-
thermic reaction in which chromite is crushed and intimately mixed with
powdered aluminum and ignited. The aluminum replaces the chromium form-
ing Al^O- and Cr metal. Due to the explosive nature of the reactions,
the process is carefully regulated. No data was found that would allow
estimation of an emission factor for this process. However, metal pro-
duction by this process totaled only 3,000 tons in 1970, indicating a
negligible quantity of emission, at most.
3. Refractory Processing
The production of refractory brick consumed 67,000 tons
of chromium in 1970, or 16 percent of the total product. The three
major types of brick produced were chrome, composed almost totally of
chromite ore; chrome-magnesite, composed predominantly of chrb-
mite with some magnesite ore; and magnesite-chrome, comprised predomin-
antly of magnesite with some chromite ore. The bricks produced are
either fired, unfired, or electric cast. The emissions from firing alone
are reported as negligible (one source reported 0.2 Ib/ton uncontrolled),
and so fired and unfired brick emissions are treated together as "non-cast."
The preliminary processing includes fine crushing and careful sizing and
mixing to obtain appropriate porosity, and drying. Uncontrolled emissions
14
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from these processes have been estimated at 150 Ib/ton. ' Production
statistics are not sufficiently detailed, so it is estimated that 90
percent of the chromium used in refractory materials is used in non-cast
materials. The concentration of chromium in the emitted particulate is
assumed to be in the same proportion as the chromium in the product.
(4)
Overall control effectiveness is reported as 64 percent, giving an
estimated emission of 1630 tons of chromium in 1970.
Electric casting includes, in addition to material prepa-
ration, melting in an electric arc furnace and pouring into molds. An
(4)
emission factor of 225 Ib/ton is estimated. An estimated 10 percent
of the chromium used in refractory materials is used in cast bricks.
The concentration of chromium in the particulate is assumed to be the
same as in the product. Overall control effectiveness is reported as
(4)
77 percent, giving an estimated emission of 170 tons of chromium.
4. Chemical Processing
All chemical products containing chromium are made from
either dichromate or chromate as the primary ingredient. Chromite ore
is roasted with soda ash or lime to form a soluble chromate. This is
leached, precipitated, and dried as a crystaline sodium dichromate.
Ore containing an estimated 61,000 tons of chromium was
roasted in 1970. Typical emissions are reported to be 11 Ib/ton before
control and in one other case, 62 Ib/ton. A weighted average of
15 Ib/ton is utilized. The chromium content of the particulate is re-
ported to be about 15 percent. It is estimated that the level of
control effectiveness was about 90 percent in 1970. This results
in an estimated emission of 46 tons of chromium.
Handling the roasted material preparatory to leaching
(12)
generates enough particulate to be controllable by scrubbing.v ' The
net emission is believed to be negligible in comparison with other
sources. Drying of the precipitate in a kiln also generates some emis-
sions. No data are available on these operations, but the net emission
to the atmosphere is probably of the same magnitude as the roasting
15
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process. In effect, therefore, the overall emission factor is estimated
to be 30 lb/ton, giving a net emission estimate of 92 tons of chromium
in the preparation of dichrornate. This estimate for 1970 may be higher
than appropriate for 1973. It is reported that one of the newer plants
passes all its exhaust gases through one stack, after scrubbing plus
electrostatic precipitation, with an effective control of 98 percent
efficiency.
Subsequently, dichromate and chromate are made into other
chemicals and used in a wide variety of applications, including tanning,
chrome plating, paints and pigments, and other applications. In general,
reliable emissions data are not available for these many processes. For
chrome plating, an emissions factor of 0.048 lb/ton (Cr/Cr) is developed
in a previous section of this report. It is estimated that among the
approximately 1400 plating plants in the U.S., the level of control ef-
fectiveness is only half as good as in the production of chromium metal;
that is, an effectiveness of 90 percent is assumed. This results in a
net emission estimate of only 0.04 tons of chromium. As for paints and
pigments, using an estimated 0.1 percent emission factor and assuming 50
percent control results in only 6 tons of chromium emission. At the same
rate, tanning and other uses of dichromate would produce about 18 tons
of emissions, for a total estimate of 24 tons.
5. Steel and Alloys
Emissions from the steel industry's use of ferrochromium
and chromium metal are based on a weighted average of emissions from the
production of steel. It is assumed that chromium is emitted to the same
extent as the other constituents, based on the fact that the vaporiza-
tion temperature of chromium (2665 C, Section V) is not extremely dif-
ferent from those of iron and nickel, all of which are well above the
typical steel production temperature of about 1500 C. The level of con-
trol is also a weighted average of control in the iron and steel indus-
try. Emissions from alloy and superalloy (high chrome) productions are
judged to be comparable to steel production in that the types of pro-
cesses employed are similar. Similar control methods are used and
16
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consequently the control factor is estimated to be the same. The re-
sult of these assumptions is an estimated 555 tons of chromium emitted
to the atmosphere. Most of this emission is contributed by the produc-
tion of steel containing chromium as an ingredient (predominantly stain-
less steels; also tool steels).
Not included above is the production of ferrous products
including iron and steel in which chromium or ferrochromium is not a
deliberate ingredient. Chromium must be a trace metal in most steel
products, particularly those containing scrap. Chromium is also a trace
metal in coke, one of the ingredients utilized in steel manufacturing.
Furthermore, a large tonnage of chromium-containing refractory materials
is consumed by the steel industry for furnace lining and patching. In
1970, open hearth steel making consumed 60,000 tons of chrome-predominant
basic brick, while electric furnace and basic oxygen furnace steel making
consumed about 230,000 tons of unspecified basic brick. Possibly one
half of these materials are consumed in producing the steel, while the
remaining brick is replaced periodically. The fate of the chromium in
these furnace linings is not reported, but some may be emitted. There-
fore, since scrap, coke, and refractory materials may possibly each con-
tribute to chromium emissions, and since the tonnages are potentially
large, a token 100 tons emission is included in Table 2 from this gener-
al source, subject to further investigation.
6. Inadvertent Sources
a. Coal Combustion
The concentration of chromium in coal ash has been reported
as 0.026 percent (73 Appalachian coal ash samples, spectrographic analy-
ses), as 0.019 (four samples, emission spectrographic analyses),
and as 0.013 percent (survey of about 15 U.S. and European investiga-
tions). ' The number 0.026 percent was utilized as the largest and
therefore most conservative estimate. Coal consumption in 1970 amounted
(2)
to about 517,000,000 tons. ' The particulate generated has been esti-
mated at 33,800,000 tons, of which 82 percent was controlled, leaving
17
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(3)
6,100,000 tons of emission to the atmosphere. This results in an
estimated emission of chromium to the atmosphere of 1,564 tons in 1970.
Section V-D, presented later, indicates that chromium
is more concentrated in particles smaller than 1.7 micrometers diameter
than in larger particles. Control equipment is often less efficient on
smaller particles, although this depends on the equipment and on other
properties of the particles, as well as size. If flyash particles under
1.7 micrometers are less well controlled than average, then more chromium
will be emitted than is indicated in Table 1.
b. Oil Combustion
An estimated 287,000 tons of flyash from the combus-
(3)
tion of residual oil has been estimated which escapes to the atmo-
sphere almost completely uncontrolled. The amount of chromium in the
(3)
ash varies considerably: 0.11 percent (two oils, method unspecified),
0.27 percent (three oils, atomic absorption spectrophotometry);
0.0064 percent (three oils, optical emissioij spectroscopy);^ ' and
0.12 percent (one oil, method unknown). Using 0.13 percent as the
average percentage of chromium in residual oils, an estimated 370 tons
of chromium were emitted to the atmosphere in 1970.
c. Cement Production
An estimated 934,000 tons of particulate emission
(3")
after control has been found for cement production. ' Again the concen-
tration of chromium in the particulate varies. A preliminary survey re-
/T Q \
ported 41 ppm, or 0.0041 percent content (method unspecified);
tests of dusts from three kilns and three clinker coolers indicated
0.17 percent; and tests from several cement mills, air separators, and
bagging operations indicated an average of 0.039 percent (spectrographic
analyses). ' Using a median 0.03 percent results in an estimated 280
tons of chromium emitted to the atmosphere in 1970.
18
-------
d. Incineration
An estimated 931,000 tons of particulate are released
to the atmosphere from all types of incineration sources. Based on a
single determination of chromium content in incinerator ash of 0.017
percent (spectrographic analyses), a chromium emission of 158 tons is
estimated.
e. Asbestos
Based on an estimated pre-control national emission
(19)
of 6579 tons of asbestos and a concentration of chromium in chryso-
lite, the chief constituent in asbestos, 0.15 percent, the net chrom-
ium emission is estimated at 10 tons. This however is before control,
which is estimated to be sufficiently close to 100 percent that negli-
gible chromium emissions result.
C. SUMMARY OF PRINCIPAL EMISSIONS
Table 3 summarizes the major sources and estimated emissions
of chromium, as developed in Table 2 and accompanying discussion. The
sources are grouped in two categories; those directly originating with
the chromium industry and those having no relationship to the chromium
industry, called inadvertent sources. The latter category represents
about 12 percent of the total estimated emission.
These principal estimates are examined further in later sec-
tions of this report.
19
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TABLE 3
SUMMARY OF PRINCIPAL SOURCES AND EMISSIONS OF CHROMIUM
Source
Chromium Industry Sources
Ferrochromium production
Refractory production
Chromium steel production
Inadvertent Sources
Coal combustion
Oil combustion
Cement
U.S. Tons/Year of Cr
12,360
1,800
520
1,564
370
280
% of U.S. Total
68.3
9.9
2.. 9
8.6
2.0
1.5
20
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IV. REGIONAL DISTRIBUTION OF PRINCIPAL SOURCES AND EMISSIONS
For the purpose of showing geographical distribution, the U.S. was
divided into ten regions identical to the Regional Branches of EPA.
States
Connecticut, Maine, Massachusetts, New Hampshire,
Rhode Island, Vermont
II New Jersey, New York, Puerto Rico, Virgin Islands
III Delaware, Maryland, Pennsylvania, Virginia, West
Virginia, District of Columbia
IV Alabama, Florida, Georgia, Kentucky, Mississippi,
North Carolina, South Carolina, Tennessee
V Illinois, Indiana, Michigan, Minnesota, Ohio,
Wisconsin
VI Arkansas, Louisiana, New Mexico, Oklahoma, Texas
VII Iowa, Kansas, Missouri, Nebraska
VIII Colorado, Montana, North Dakota, South Dakota,
Utah, Wyoming
IX Arizona, California, Nevada, Hawaii, and the South
Pacific
X Alaska, Idaho, Oregon, Washington
Emissions from the principal sources listed in Table 3 are distributed
among these ten regions, as shown in Table 4. Also, the number of
plants producing the emissions are shown in the table when such inform-
ation is available.
The accuracy of the distribution by region varies with the cate-
gory. The number of plants per category varied from one to several thou-
sand in this study. When the number of plants was less than 100, an
attempt was made to identify each plant and plant location, and include
it in one of the ten regions. When production or capacity figures for
these plants were available, total production or capacity for each re-
tion was computed, and the U.S. emission estimate for that category was
distributed by region accordingly. When production or capacity figures
were not available, the emission was distributed by the number of plants
21
-------
NJ
Si
TABLE 4
REGIONAL DISTRIBUTION OF PRINCIPAL SOURCES AND EMISSIONS
EPA Region
Principal Sources
Chromium Industry Sources
Per ro chrome Production
Refractory Production
Chrome Steel Production
Inadvertent Sources
Coal Combustion
Oil Combustion
Cement Production
TOTALS
1
0
0
0
0
33
9
11
0.7
67
18.0
2
1
113
~5~6-
2
2852
3
180
4
204
56
89
5.7
108
29.1
20
13
3453
I9"76"
3
1902
2
675
15
120
33
339
21.7
55
15.0
~28
3134
ITT
4
2852
3
90
2
10
3
328
21.0
35
9.6
42
27
3357
IS??
5
3803
4
630
14
120
33
643
44.1
28
7.6
45
^5269
2"9~76~
6
0
0
0
0
4
1
22
1.4
14
3.7
42
27
82
TTT
7
0
0
90
2
7
2
64
4.1
3
0.9
31
20
195
TT
8
0
0
45
1
0
0
52
3.3
7
1.8
14
9
118
9
0
0
90
2
18
5
11
0.7
43
11.6
30
19
192
1.1
10
951
1
0
0
4
1
5
0.3
10
2.7
11
7
981
5.4
Total
12360
13
1800
40
520
143
1564
100
370
100
280
181
16894
Units Reference
CTPY)
(No. Plants)
(TPY)
(No. Plants)
(TPY)
(No. Plants
(TPY)
(7. Coal)
(TPY)
tt Oil)
(TPY)
(No. Plants)
2
20
21
2
17_
22_
(TPY)
93.2 (7. of U.S.)
-------
in each region. If the number of plants was very small or there was
reason to believe that certain plants were larger or produced more emis-
sion, distributions were weighted accordingly.
On the other hand, when the estimated number of plants was greater
than about 100, and the distribution of plants was not known, the re-
gional breakdown was made on a different basis, such as population, geo-
graphical area, or shipments reported, as most appropriate for that cate-
gory. Whether the distribution was by plant size, number of plants, or
another statistic, the distribution is believed to be accurate-to within
10 percent in most cases.
As indicated in Table 4, the distribution of ferrochromium emissions
was according to number of plants, on the assumption that all plants are
about the same size and produce similar emissions. Due to the large
total estimated emission from ferrochromium production, this assumption
is rather critical to the conclusions of the study, as a single ferro-
chromium plant is thereby assumed to emit about 4.4 percent of the total
U.S. emissions of chromium.
The distribution of emissions from production of chromium-containing
refractory materials is according to the number of plants. Somewhat more
than the 40 plants identified in this study may produce these materials,
(23)
according to the Bureau of Mines. However, the principal plants
should be included in the present distribution, and any small plants in-
advertently omitted may be assumed to be distributed in about the same
proportions as the large plants, to a first approximation.
Emissions from the production of chromium-containing steels are
also distributed by number of plants. The reference used to identify
these plants purports to survey all alloys made in the U.S. Most of
the plants identified are located in the eastern U.S., however, which
is where the survey is headquartered, indicating that possibly the sur-
vey does not truly cover the U.S. uniformly. In addition, parts of the
survey date back to 1952. Thus the confidence in this particular dis-
tribution of emissions is relatively low.
23
-------
The inadvertent emission sources are distributed as follows: Coal
emissions are distributed according to tonnage of coal shipped, by
state of destination. Oil emissions are distributed by total sales of
residual oil, for all uses, by states. Cement emissions are distributed
by number of producing plants, based on a fairly accurate survey which
does, however, omit cement handling plants (loading, unloading, wet
mixing stations, etc.), which are widely distributed across the U.S.
As a result of these distributions of the six principal emissions
categories, Region V (Ohio-Minnesota) is estimated to have the "largest
emission of chromium (29 percent of U.S.), followed by Regions II, III,
and IV (the eastern seaboard states). This distribution is largely the
result of the estimated emissions from the production of ferrochromium,
which makes up about half the total estimated U.S. emission of
chromium.
Considering the geographical areas of the ten regions. Region II
has the most concentrated emission of chromium with an average 0.05?
tons of chromium emitted per square mile-year.
24
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V. NATURE OF EMISSIONS
The physical and chemical properties of the emitted particles con-
taining chromium are the direct results of the processes causing the
emission, the types of feed materials, and the characteristics of chrom-
ium and its compounds. Some of the latter are summarized in Table 5.
Of those listed, the boiling (vaporization) point for chromium of
2665 C may be the most important, in that temperatures below this point
may be expected to produce relatively little chromium or chrornate fume,
while higher temperatures can produce substantial amounts of fume par-
ticulate. With this brief background, the emissions from the principal
sources will be examined in turn.
TABLE 5
SOME PHYSICAL PROPERTIES OF CHROMIUM AND ITS COMPOUNDS*
Melting point: 1875°C
Boiling point: 2665°C (for Cr,0,:4000°C)
3
Density: 7.2 g/cm
Atomic weight: 52.0 a.w.u.
Heat of vaporization: 73.0 kg-cal/g-atom
Mineral hardness of chromite: 5.5 (Std. minerology scale)
Reference 24, Table 3-169.
A. FERROCHROMIUM PRODUCTION EMISSIONS
Emissions from high-carbon ferrochrome furnaces are reported
as follows:
. 1.07 grains/SCF,' ' before scrubber control at 98.2
percent efficiency
. Approximately 1.0 micrometer diameter particles
containing 29.3 percent Cr^O,
. Dust collected by an electrostatic precipitator con-
tained 4 percent Cr, and 15 percent Mg' '
25
-------
quartz; 21 percent Si02; 11 perc
MgO; 29.3 percent Cr90^; etc.^3)
An unspecified type of ferrochrome furnace emitted
particulate varying from 1 to 2 micrometers in
diameter. Control by electrostatic precipitator
did not alter the relative concentration of chrom-
ium and other metals in the dust, which included
14 percent chromium and 8.9 percent magnesium. ^ '
A maximum of 1.0 micrometer in diameter, with most
particles from 0.1 to 0.4 micrometers; amorphous,
spherical particles, including traces of spinel and
ent FeO; 15 percent
9^ etc.
1 f\
. Fume resistivity: 9.4 x 10 ohm-cm, 200OOO°F; or
with conditioning of gas to 20 percent moisture,
21 x 1010 ohm- cm.
. Emissions from ferrochrome silicon furnaces are re-
ported as follows:
, (8)
1.43 grains/SCF before scrubber control
at 92.6 percent efficiency.
0.245 grains/SCF from a hooded furnace
without control equipment. This particulate
described as non-crystalline fused silica
and impurities, the fume containing 1.3 per-
cent chromium and 6.8 percent magnesium.
0.65 micrometer mass median 'diameter.
B. REFRACTORY PRODUCTION EMISSIONS
No useful description of these emissions was found, and conse-
quently the following estimates are made. Most of the emissions from
refractory production operations are from grinding, screening, mixing,
and drying'. All except grinding are relatively low- intensity opera-
tions which are therefore expected to generate particles and agglomer-
ates roughly 5 micrometers in diameter arid larger, having relatively
short distances of travel before disposition. Grinding material having
the moderate hardness of chromite is expected to generate moderately
small rough- shaped particles, perhaps 1 micrometer in diameter and
larger, of which the smallest may travel distances up to a few miles
before disposition. Most of the chromium emitted ;Ls expected to be in
the chromite form; i.e., FeO ' Cr-O.,.
26
-------
C. CHROME STEEL PRODUCTION EMISSIONS
Emission characteristics are known to be highly dependent on
(3)
the material charged to the furnace. Probably some particles con-
sisting almost entirely of Cr20- will be emitted, while other particles
will contain Fe?0_ and FeO up to 50 percent, plus numerous other metal-
lic oxides. Most particles will be spherical, and submicrometer in size,
although seme will exceed 1 micrometer in diameter.
D . COAL COMBUSTION EMISSIONS
Analyses of flyash give average particle diameters from 2 to
30 micrometers (mass median diameter) depending on the type of feed to
the furnace. From 1 to 10 percent of the particle mass may be submi-
crometer. The concentration of chromium in flyash as a function of
(25)
particle size is reported:
Particles less than 1.7 micrometers: 0.4 percent chromium
Particles 1.7 to 4.1 micrometers: 0.05 percent chromium
Particles 4.1 to 30 micrometers in
6 increments and over 30 microm-
eters: 0.02 perc.ent chromium
This indication that chromium is concentrated in the smaller particles
is not explained by the vaporization temperature of chromium, which is
well above the combustion temperature of coal (about 1500 C).
E. OIL COMBUSTION EMISSIONS
Most particles are between 0.01 and 1 micrometers in diameter,
depending on the atomization and combustion processes. Thus, these
particles tend to travel long distances (tens to hundreds of miles) be-
fore being removed from the atmosphere by natural processes (settling,
washout, agglomeration). The chemical form of the chromium contained
in these emissions is not stated, although one report gives "chromium
as CrOJ1 data of 0.06 and 0.3 percent of ash, indicating that this may
(3)
be the chemical form.
27
-------
F. CEMENT PRODUCTION EMISSIONS
Most emissions from cement plants come from the kilns from
(3)
which 5 percent of the material may be submicrometer. Up to 50 per-
cent of the particulate can be CaO; and silicon, iron, and aluminum
oxides represent a large portion of the remaining particle contents.
G. AMBIENT CHROMIUM AND TOXICITY
Analyses of the air in and near Cincinnati is reported to con-
tain 0.28 and 0.31 micrograms of chromium per cubic meter, in particles
of average size 1.5 and 1.9 micrometers (mass median diameter). Of the
particles containing chromium, 45 and 74 percent were greater than 1 mi-
crometer, somewhat larger than would be predicted from the preceding
A- • (26>
discussions.
Although not a principal source of emissions, chromium plating re-
leases chromic acid particles in the form of chromium trioxide which is
(9)
said to be poisonous and injurious to the kidneys. Dust from cement
plants is said to cause skin problems with some workers, due to the
chromium contained in the dust. Chromium-containing chemicals are used
as preservatives of wood, slimicides, and herbicides, indicated a po-
tential toxicity to organisms in at least some chemical forms.
28
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VI. UPDATING OF EMISSIONS ESTIMATES
The following recommendations are made for periodically updating
the estimates made in this study:
A. VERIFICATION OF CURRENT ESTIMATES
1. Verify the estimates of chromium emission from the produc-
tion of ferrochromium and ferrochrome silicon. Following the publica-
tion of Reference 5, comment should be obtained from the manufacturers
of these products regarding the data and estimates contained in these
two reports.
2. The refractory industry has not published much informa-
tion establishing either particulate emission nor the form and content
of chromium contained in the particulate. In view of the size of the
emissions estimated here, a brief study should be made of this industry.
3. In view of the apparent toxicity of certain forms of chrom-
ium, and perhaps the non-toxicity of other forms, representative par-
ticulate samples from the six principal sources identified in this study
should be analyzed to determine the form of chromium contained therein.
B. PERIODIC REVIEW OF ESTIMATES
1. The Bureau of Mines estimates for material flow, industry
practices, and trends provide the best estimates of the size of the
industry.
2. EPA activities are currently generating the best emissions
data and should be reviewed using:
a. Overall industry studies; e.g., Reference 5.
b. The Source Test Program, in which specific in-
dividual plant emissions are measured. This
information provides emission factors for spe-
cific examples of typical industrial opera-
tions; and also provides some analyses of the
particulate usually including trace metal con-
tent and particle size.
29
-------
c. NEDS (National Emissions Data System) is
steadily being enlarged and improved. This
system can provide emission factors for
specific plants and plant operations, the
type of particulate control equipment in
use, and the actual, or estimated, control
efficiency. The system may eventually be
expanded to include description of the
emissions.
3. The chromium industry should be consulted for its opinion
and suggestions on the most recently published estimates. This may
be best accomplished by interviewing the Chromium Commodity Specialist,
Division of Non-ferrous Metals, Bureau of Mines in Washington; or, by
interviewing one or more of the principal companies in the industry.
4. The literature should be reviewed using (a) industrial
views as published from time to time in Chemical Engineering, for ex-
ample; and (b) environmental views as summarized in Pollution Abstracts,
for example.
5. Individual companies or plants .may be approached for opin-
ions, data, or cooperative tests of their own operations. This is a
difficult approach to the problem of obtaining of fresh information
due to the natural reluctance of the plants to discuss environmental
problems. However, data thus obtained have a relatively high degree of
reliability.
6. State agencies in which specific plants are located may
be able to provide useful information, and should be contacted.
30
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VII. REFERENCES
1. Mineral Facts and Problems, Bureau of Mines 650, U.S. Govern-
ment Printing Office, Washington, B.C. (1970).
2. Minerals Yearbook, 1970. Bureau of Mines, U.S. Government
Printing Office, Washington, D.C. (1972).
3. Particulate Pollutant Systems Study Volume III; Handbook of
Emission Properties, A.E. Vandegrift, et al., Midwest Re-
search Institute, Kansas City, Mo. (1971).
4. Compilation of Air Pollutant Emission Factors, U.S. Environ-
mental Protection Agency, Research Triangle Park, N.C. (1972).
5. Atmospheric Emissions From the Ferroalloy Industry, a report
to be published by EPA in mid 1973.
6. NEDS (National Emissions Data System) information obtained
from EPA.
7. Source Test Reports of Emissions From Specific Industrial
Operations, obtained in part from EPA.
8. Person, R.A., Control of Emissions From Ferroalloy Furnace
Processing, Union Carbide Corp., Niagara Falls, N.Y., paper
presented at the 27th Electric Furnace Conference, Detroit,
Mich., Dec. 1969.
9. Tokyo Metropolitan Government, Japan, "The Emission Sources
of Nitrogen Oxide and Chromic Acid and Their Standard Con-
trol Equipments," J. Pollution Control 3_, (7) 411 July, 15,
1967. APTIC Abstract No. 15625, EPA.
10. Mantell, C.L., Electrochemical Engineering. 4th Ed., McGraw-
Hill Book Co., New York, 1960.
11. "Pollution Control in Chrome Chemical Plants," Chemical Week,
pp. 77-78 (June 21, 1972).
12. Personal Communication with members of the Chromium industry.
13. Kusler, D.J., and Clarke, R.G., Impact of Changing Technology
on Refractories Consumption, Bureau of Mines I.C. 8494,
Washington, D.C. (1970).
14. Zubovic, P., et al., Distribution of Minor Elements in Coals
of the Appalachian Region, Geological Survey Buileting No.
1117-C, U.S. Bureau of Mines, Washington, D.C. (1966).
15. Abernathy, R.F. and F.H. Gibson, Rare Elements in Coal, U.S.
Bureau of Mines Information Circular IC-^8163 (1963).
31
-------
16. Levy, A., et al., A Field Investigation of Emissions From
Fuel Oil Combustion for Space Heating, Report by Battelle
Inst., Columbus, Ohio to American Petroleum Institute, API
Proj. SS-5, 1 Nov. 1971.
17. American Petroleum Institute, Petroleum Facts and Figures,
1971, The Inst., Washington, D.C.
18. Preliminary Air Pollution Survey of Chromium and Its Com-
pounds, Ralph J. Sullivan, Litton Systems, Inc., Raleigh,
N.C. (1969).
19. National Inventory of Sources and Emissions - 1968: Asbestos,
Davis, W.E. and Associates, Leawood, Kansas (1970)."
20. The Refractories Institute, Product Directory of the Refrac-
tories Industry in the U.S., 1968, The Ref. Inst., 3154 One
Oliver Plaza, Pittsburgh, Penn., 15222.
21. Alloys Digest, a series of descriptions of individual alloy
products and manufacturers, pub. since 1952 by Engineering
Alloys Digest, Inc., Upper Monclair, N.J.
22. Pit and Quarry Publications, Inc., Chicago, 111., Portland
Cement Plants (map) (1969).
23. Discussion with the Chromium Commodity Specialist, Division
of Non-ferrous Metals, U.S. Bureau of Mines, Washington, D.C.
24. Perry's Chemical Engineer's Handbook, 4th Ed., McGraw Hill,
Inc., New York (1963).
25. Lee, R.E., Trace Metals in Fly Ash as a Function of Particle
Size, a single-page table, via personal communication, EPA,
Research Triangle Park, North Carolina.
26. Lee, R.E., "Particle-Size Distribution of Metal Components
in Urban Air," Environmental Science and Technology, 2_, (4)
288, April 1968.
Other References of General Interest
27. Economic Analysis of the Chromium Industry, Charles River
Associates, Inc., Cambridge, Mass. (1970).
28. National Materials Advisory Board, Trends in Usage of Chrom-
ium. Washington, D.C. (1970).
29. Udy, M.J., Chromium Vol 1 Chemistry of Chromium and Its
.Compounds, American Chem. Soc., New York, Rheinhold (1956).
32
-------
30. Udy, M.J., Chromium Vol 2 Metallurgy of Chromium and Its
Alloys, American Chem. Soc., New York, Rheinhold (1956).
31. Air Pollution Aspects of the Iron and Steel Industry, U.S.
Public Health Service Pubs 999-AP-l, Cincinnati, Ohio (1963).
32. Sully, A.H. and E.A. Brandes, Chromium Metallurgy of the
Rarer Metals, Plenum Publishing Corporation, New York (1967).
33. Romagnoli, E., "Chrome Ore," Engineering and Mining J., p.
134-137 (May 1970).
34. Campbell, W.W., and R.W. Fullerton, "Development of an Elec-
tric Furnace Dust Control System," J. of Air Pollution Contr.
Assoc.. p. 574-577 (Dec. 1962).
33
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
I REPORT NO. 2.
1 EPA-450/3-74-012 •
, i. TITLE AND SUBTITLE
\ National Emissions Inventory of Sources and
: Emissions of Chromium
; AUTiHOR(S)
t
1
.'
J. PI RFORMING ORGANIZATION NAME AND ADDRESS
GCA Corporation
GCA Technology Division
Bedford, Massachusetts 01730
'12. SPONSORING AGENCY NAME AND ADDRESS
I
i Environmental Protection Agency
I Research Triangle Park, N. C. 27711
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
May 1973
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
2AE132
11. CONTRACT/GRANT NO.
68-02-9601
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
>
jib. SUPPLEMENTARY NOTES
lib. ABSTRACT
A national inventory of the sources and emissions of the element chromium
was conducted. All major sources of chromium-containing emissions were iden-
tified and their chromium emissions into the atmosphere estimated. Also, a
method for updating the results of the study every two years was recommended.
;i7. KEY WORDS AND DOCUMENT ANALYSIS
,1. DESCRIPTORS
1
i, Chromium
Air Pollution
Emission
Inventories
Sources
(IS. DISTRIBUTION STATEMENT
Release Unlimited
b. IDENTIFIERS/OPEN ENDED TERMS
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS, fffils page)
Unclassified
c. COSATI Field/Group
21. NO. OF PAGES
33
22. PRICE
EPA Form 2220-1 (9-73)
34
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