ENVIRONMENTAL HEALTH SERIES
Air Pollution
ATMOSPHERIC
EMISSIONS
FROM THE
MANUFACTURE OF PORTLAND CEMENT
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service .
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ATMOSPHERIC EMISSIONS FROM THE
MANUFACTURE OF PORTLAND CEMENT
Thomas E. Kreichelt
Douglas A. Kemnitz
and
Stanley T. Cuffe
National Center for Air Pollution Control
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Bureau of Disease Prevention and Enviromental Control
Cincinnati, Ohio
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The ENVIRONMENTAL HEALTH SERIES of reports was established
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vironment: The community, whether urban, suburban, or rural, where
he lives, works, and plays; the air, water and earth he uses and reuses;
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Public Health Service Publication No. 999-AP-17
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CONTENTS
Page
Abstract v
Introduction 1
Summary 1
Industry Growth 3
Location of Cement Plants 3
Production 3
Raw Materials 6
Fuel Consumption 8
Cement Production Process 8
Quarrying and Crushing 10
Mixing and Grinding 10
Dry Process 10
Wet Process . . 11
Clinker Production 11
Finish Grinding and Packing 13
Emissions and Their Control 13
Crushing 13
Raw Drying and Grinding Dry Process 15
Raw Grinding - Wet Process 16
Kiln Operation 16
iii
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Gaseous Emissions
Particulate Concentrations Before Dust
Collectors ........................... 18
Dry Process ...................... 19
Wet Process ...................... 19
Evaluation of Dust Control Equipment as it Affects
Kiln Effluent .............................. 22
Grate Preheater Process ..................... 25
Clinker- Cooler Emissions ..................... 26
Finishing and Shipping ....................... 26
Trends ..................................... 26
Acknowledgments ............................... 27
References ................................... 29
Appendix ................................... 31
IV
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ABSTRACT
This report summarizes published and unpublished information on
actual and potential atmospheric emissions resulting from the manu-
facture of cement. Raw materials, process equipment, and production
processes are described, as well as the location of plants, and process
trends. Emission and related operating data are presented, along with
methods normally employed to limit or control emissions from the dry,
semi-dry, and wet processes.
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ATMOSPHERIC EMISSIONS FROM THE
MANUFACTURE OF PORTLAND CEMENT
INTRODUCTION
This report has been prepared to provide reliable information on
actual and potential atmospheric emissions from portland cement man-
ufacturing plants and on methods and equipment normally employed to
limit these emissions to satisfactory levels.
Background information has been included to define the importance
of the cement industry in the United States. Basic characteristics of
the industry are discussed, including projected growth rates, types of
raw materials, and the number and location of cement manufacturing
sites in the United States.
Process descriptions are given for both the wet process and the
dry process to provide a basic understanding of these processes for
those interested in dust emissions originating from the manufacture of
cement. Emissions from both processes are reviewed in detail,
normal ranges are given, and methods of emission control and re-
covery are described.
Because the cement industry in the United States has been a basic
industry for many years with well-established manufacturing proce-
dures, and indications are that the industry growth in recent years
closely parallels the growth curve of the general economy, the infor-
mation provided in this report on emissions and their control may
likely provide characteristic information for a period of 5 to 10 years.
Although this review of the industry has been prepared primarily
for public officials concerned with the control of air pollution, the
information may also be useful to cement plant management and tech-
nical staffs and to other professional people interested in emissions
from portland cement manufacturing plants.
SUMMARY
In 1964, production of portland cement in the United States was
approximately 361,000,000 barrels. Cement production is expected to
increase at the rate of about 5 percent per year, with a comparable
increase in the construction of new plants. (See Figure l.)l>2,3
All portland cement is made by either the wet process or the dry
process. Almost all new plants utilize long kilns (greater than 400
feet) with chain or other preheating systems.
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1,800
1,600
I ,WO
1,200
1,000
800
600
too
200
"1 1 T
1 1 1 1 1 1 1 r
/ (PROJECTED TREND)
I
I
I
I
I
I
I
I
I
I
I
1930 19^0 1950 I960 1970 1980 1990 2000
Figure 1. Portland cement production in the United States (References 1, 2, and 3).
The main source of emissions in the cement industry is the kiln
operation. Dust generated in the dry-process kiln may vary from 1 to
25 percent expressed in terms of finished cement; from the wet pro-
cess, 1 to 33 percent. Sulfur dioxide emissions from the kiln opera-
tion are generally minor; most of the oxides of sulfur in the kiln gases
combine with the alkalies as condensed sulfates. In the wet process,
an odor problem may arise from heating certain types of raw material
such as marine shells, marl, clay, or shale.
Another important source of dust emissions in the cement industry
is the dryer normally used in dry process plants.
ATMOSPHERIC EMISSIONS FROM THE
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Dust can be adequately arrested in the cement industry by proper
plant layout and proper selection of high-efficiency multicyclones,
electrostatic precipitators, or fabric filters. Electrostatic precipita-
tors or fiber-glass fabric filters that have been properly designed,
installed, operated, and maintained will adequately collect the dust
from the hot kiln gases. In many plant designs, multicyclones precede
the precipitator or fabric filter. Precipitators or low-temperature
fabric filters alone may be adequate on other unit operations such as
handling, crushing, grinding, drying, and packaging. Dust emissions
as low as 0.03 to 0.05 grains per standard cubic foot have been obtained
in newly designed well-controlled plants.
INDUSTRY CHARACTERISTICS
LOCATION OF CEMENT PLANTS
The availability of markets and raw materials determines the loca-
tion of a cement plant. The more important considerations are: (1) a
potential market nearby or within the range of low cost transportation;
(2) suitable raw materials sufficient to supply a plant for 50 to 100
years; (3) adequate transportation facilities for shipping the finished
product to its destination; (4) adequate fresh water of a quality suitable
for process use, cooling, cleaning, and washing; (5) adequate uniform-
quality fuels available at attractive prices; (6) available skilled and
unskilled labor; and (7) available electric power at an attractive rate.
To meet these conditions, cement plants are concentrated in certain
groups or patterns (Figure 2): (1) eastern Pennsylvania and the
Hudson River Valley, serving the eastern metropolitan areas; (2)
Birmingham, Alabama, area, serving the central south; (3) St. Louis
and Kansas City, Missouri, areas, serving the midwest; (4) central
Texas; (5) California; and (6) the Pacific Northwest. In addition to
these concentrations, cement plants are located convenient to other
markets and available materials. For example some plants are
located in the Appalachian Mountains because of the availability
of a certain type of limestone, and other plants are located in
West Texas, Oklahoma, Kansas, and Louisiana to take advantage
of available natural gas as fuel.
Table 1 lists districts in which portland cement manufacturing
plants were located in the United States as of December 31, 1964, and
their approximate total capacities.
PRODUCTION
In 1964, the United States produced 361,000,000 barrels of port-
land cement, a 4.3 percent growth over 1963 (see Figure 1). This is
75.5 percent of the 1964 rated capacity of 478,000,000 barrels.4 The
production rates for 1963, estimated percentage of utilization in 1963,
and capacity rates for 1964 are summarized by area location in
Table I.1
MANUFACTURE OF PORTLAND CEMENT 3
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Table 1. PORTLAND CEMENT MANUFACTURING CAPACITY OF
THE UNITED STATES BY DISTRICTS, 1964 (References 4,5, and 6)
District
New York, Maine
Eastern Pennsylvania
Western Pennsylvania
Maryland, West Virginia
Ohio
Michigan
Illinois
Indiana, Kentucky,
Wisconsin
Alabama
Tennessee
Virginia, North Carolina.
South Carolina
Georgia. Florida
Louisiana. Mississippi
Iowa
Minnesota. South Dakota,
Nebraska
Kansas
Missouri
Oklahoma. Arkansas
Texas
Colorado. Arizona, Utah.
Ne\\ Mexico. Nevada
Wyoming. Montana. Idaho
Northern California
Southern California
Oregon. Washington
Hawaii
Total
Approximate capacity
in thousands of
Active barrels, Dec. 31,
plants 1964
14
14
5
4
9
9
4
8
9
6
5
7
5
5
4
6
5
5
17
8
4
6
7
9
o
177
43,406
36,118
11,758
12,150
19,700
35,472
12,250
28,600
19,540
10,024
13,790
20,472
9,800
15,680
10,100
13,440
15,800
15,200
42,650
19,600
4.800
20,800
38.650
11,410
2.700
483,910
Production in
thousands of
barrels, 1963
24,033
30,480
7,956
10,277
16,375
24,388
9,588
19,166
12,575
8,793
8,562
11,288
8,304
12,790
7,856
8,248
12,624
11,282
29,089
13,488
3,614
17,973
28,120
7,799
1,429
346,097
Estimated
percent uti-
lized, 1963
76
84
68
84
72
67
94
85
73
83
78
76
79
87
84
64
76
70
60
84
83
86
72
75
50
73.8
ATMOSPHERIC EMISSIONS FROM THE
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o
H
cl
o
3
f
o
o
Figure 1. Portland cement plant locations in the United States (1965).
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Portland cement is produced by either the dry or the wet process.
In 1964 there were 110 wet-process and 69 dry-process plants in the
United States (see Figure 2). The number of both wet- and dry-process
plants may be expected to increase at a comparable rate. A compari-
son of cement production by the two processes is shown in Table 2.
The individual plants, their locations, process types, and capacities
are listed in the Appendix. Although the plant capacities range from
less than 1,000,000 barrels to almost 14,000,000 barrels per year, over
50 percent of them have capacities ranging from 2,000,000 to 4,000,000
barrels per year.
Table 2. COMPARISON OF WET AND DRY PROCESS
PRODUCTION OF PORTLAND CEMENT (Reference 1)
No. of plants
1964 approximate total
capacity, 1,000 bbl
Percent of
total capacity
1963 total production,
1,000 bbl
Percent of total
production
Wet Process
110
285,270
58.9
202,097
58.4
Dry Process
69
198,640
41.1
144,000
41.6
aTwo plants use both wet and dry processes.
RAW MATERIALS
The raw materials required to make cement may be divided into the
following components: lime (calcareous), silica (siliceous), alumina
(argillaceous), and iron (ferriferous). In the United States more than
30 different types or classes of raw materials are used to manufacture
cement. To produce one barrel of cement weighing 376 pounds, approx-
imately 600 pounds of raw materials (not including fuel) are required.*
(Approximately 35 percent of the raw material by weight is volatilized
as carbon dioxide and water vapor.) The total tonnages of raw materials
used in producing portland cement in the United States are shown in
Table 3.
Approximately 73 percent of the domestic output of portland cement
in 1962 was made from a combination of limestone and clay or shale.
Cement rock (argillaceous limestone), a low-magnesium limestone-
containing clay, was used in about 19 percent of the portland cement
produced.1 The Jacksonburg limestone of the Lehigh Valley area of
ATMOSPHERIC EMISSIONS FROM THE
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Pennsylvania is a well-known source of cement rock. Quarry materials
are corrected to the desired composition for kiln feed by adding small
amounts of clay or high-calcium limestone.
Along the Gulf Coast of the United States, oyster or clam shells are
used as sources of calcareous material; in San Francisco oyster shells
occurring in brackish water deposits have been found suitable for ce-
ment manufacture. Other forms of calcium carbonate of relatively high
purity, such as coral rock in Florida, chalk in Alabama and Arkansas,
and alkali waste in certain parts of the United States may be used.
Where alumina, silica, and iron oxide are not present in the lime-
stone in sufficient amounts, and this is true in most cases, clay, shale,
or iron ore must be added to adjust the composition. Both clays and
shales display wide variations in mineralogical and chemical content;
some consist essentially of aluminum silicates and others may contain
more than 50 percent free silica or quartzite. Adjustment of the silica
content may be necessary.
Table 3. RAW MATERIALS USED IN PRODUCING PORTLAND
CEMENT IN THE UNITED STATES DURING 1962 (Reference 1)
Raw material Thousands of tons
Cement rock 20,829
Limestone (including oyster shell) 69,456
Marl 1,689
Clay and shale 9,943
Blast-furnace slag 1,119
Gypsum 2,826
Sand and sandstone (including silica and quartz) 1,423
Iron materials 659
Miscellaneous 105
Total 108,049
Basic blast-furnace slag may be substituted in part for the raw mate-
rials used in the production of portland cement. Where the slag is used,
the fluxing stone charged to the blast furnace must necessarily be lime-
stone with high calcium content and not dolomite with its objectionable
magnesium content. The slag is mixed with limestone and serves to in-
troduce a part of the lime, silica, alumina, and iron oxide. Another raw
material is fly ash from coal-fired power stations.
MANUFACTURE OF PORTLAND CEMENT 7
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FUEL CONSUMPTION
In the United States, coal, oil, and natural gas are used, singly or in
combination with one fuel as the main supply and the other as a standby.
Cost, availability, and convenience of handling determine the fuels used.
Only coal requires extensive preparation; a supply is kept in covered
storage bins or in piles out in the open to ensure against supply inter-
ruption, and to permit blending for the sake of uniformity. As in the
grinding of dry-process raw materials, coal may be dried in separate
driers or in a combined dry ing-grinding mill. After being ground to a
fineness of about 80 to 90 percent minus 200 mesh, the coal may be
stored in bins and withdrawn by automatic feeders for injection into the
kilns with a stream of preheated primary air. Most plants use direct-
firing-unit pulverizers, with which the dried and powdered coal is swept
through and out of the grinding mills by the heated air stream and blown
directly into the kiln. Any dust released from the coal-handling system
can be efficiently controlled by a fabric filter.
Heated fuel oil is injected into the kilns with or without the primary
air by means of compressed air or fluid-pressure-steam atomizers.
Natural gas is simply reduced in pressure before passing directly into
a kiln with or without the addition of primary air.
The amount of fuel used to manufacture cement varies with the effi-
ciency of the kiln, the composition of raw materials, the process used,
and many other operational factors. In 1963, on the average, one barrel
of finished cement required about 92.3 pounds of coal, or 8.27 gallons of
fuel oil, or 1140 cubic feet of natural gas--the equivalent of approxi-
mately 1,200,000 Btu per barrel of cement produced.*• This figure is
the statistical mean of data compiled on all makes and models of kilns
used today. Modern plants would be expected to consume much less
fuel. Long-dry-process kilns utilize about 900,000 Btu per barrel, short-
dry-process kilns with vertical suspension preheaters utilize 540,000 to
640,000 Btu per barrel, and grate-preheater-process kilns utilize approx-
imately 600,000 Btu per barrel.1 Although the wet-process kiln has a
higher heat requirement than the dry-process kiln, the fuel consumption
difference, in many cases, is partially offset by the heat consumed in
the dryers preceding the dry-process kiln. This is not the case in in-
stances where dryers do not precede dry-process kilns.
CEMENT PRODUCTION PROCESS
There are four major steps in the production of portland cement:
quarrying and crushing, grinding and blending, clinker production, and
finish grinding and packaging. Flow charts depicting the various steps
in cement production are shown in Figures 3-A, B, C, and D.
ATMOSPHERIC EMISSIONS FROM THE
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RAW MATERIALS CONSIST OF
COMBINATIONS OF LIMESTONE,
CEMENT ROCK, MARL OH OYSTER SHELLS,
AND SHALE, CLAY, SAND, OR IRON ORE PRIMARY CRI
Figure 3A. Quarrying and crushing operation of portland cement production.
RAW MATERIALS D li ]
ARE PROPORTIONED GRINDING MILL
DRY MIXING AND GROUND RAW
BLENDING SILOS MATERIAL STORAGE
RAW MATERIALS ARE GROUND TO POWDER AND BLENDED
Figure 3B. Grinding and blending operation of portland cement production.
FAN DUST
Figure 3C. Kiln operation of portland cement production.
CEMENT BULK STORAGE BULK BULK BOX PACKAGING TRUCK
GRINDING MILL
Figure 3D. Fine grinding and packaging operation of portland cement production.
MANUFACTURE OF PORTLAND CEMENT
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QUARRYING AND CRUSHING
The production of cement begins in the quarry. Although there are
numerous methods of obtaining the cement rock, limestone, clay, and
shale from the earth, most deposits are worked in open quarries with a
face height ranging from 30 to 200 feet. In many cases, heavy overbur-
den, which may run as much as 50 to 100 feet in depth, requires exten-
sive stripping and must be relocated.
Rock must be transported to crushing plants located either at or re-
mote from the quarry. The types of primary crushers used depend on
the hardness, lamination, and size of rock produced at the quarry, and
include gyratory crushers, jaw crushers, roll crushers, and heavy ham-
mer mills or impact mills.
After the rock has been broken in the primary crusher, it is carried
by conveyors to the secondary crusher where crushing may be com-
pleted in one, two, or three steps. Typical crushers are hammer mills
that reduce the rock to a maximum of 3/4 inch.
In a typical crushing plant a primary crusher may reduce the rock
from as large as 4 to 5 feet across to 6 to 10 inches, and the secondary
crusher may again reduce this product to 3/4 to 1 inch. Crushed mate-
rial is generally transported to the raw material storage area by eleva-
tor and belt-conveyor systems and deposited in piles or compartments.
MIXING AND GRINDING
The various crushed raw materials must be properly proportioned,
mixed, and pulverized to prepare them for heat treatment or clinkering
in the kiln. The crushed materials are generally proportioned prior to
the grinding operation, following which the finely ground raw mix is
blended as required. In some plants, principal raw material compo-
nents are ground separately, with both proportioning and blending ac-
complished after grinding. Product of the raw grinding circuit is so
fine that 70 to 90 percent will pass through a 200-mesh sieve. Two
grinding processes are used—dry and wet.
Dry Process
In the dry process, free moisture content of crushed materials is
reduced to less than 1 percent prior to or during grinding. The drying
may take place in direct-contact cylindrical rotary dryers, typically
6 to 8 feet in diameter and 60 to 150 feet long, or in "dry-in-the-mill"
combined drying and grinding units that utilize a mill drying compart-
ment or air separator for heat transfer. The hot gases may be provided
by direct dryer firing, from separately fired furnaces, or by hot-kiln
exit gases (waste heat). Pulverized coal, oil, or gas fuels are used.
10 ATMOSPHERIC EMISSIONS FROM THE
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The dried materials are ground to final product fineness in one or
more stages. Preliminary or first stage grinding may utilize a cylin-
drical ball mill, rod mill, or ring-roller mill. The second- or final-
stage unit is usually a ball mill or a "tube" mill, which is a ball mill
with a higher length-to-diameter ratio. Most of the more recent instal-
lations follow the secondary or tertiary crushing operation with single-
stage grinding with a combined ball-tube mill unit known as a compart-
ment mill. Some plants operate single-stage vertical ball-race mills.
Modern dry-process grinding units are usually operated in a closed
circuit with air separators that split the mill output into coarse and
fine fractions. The coarse fraction is returned to the mill for further
grinding, and the fine fraction becomes finished raw-mix. Various
types of closed circuits have been used, with units in parallel, or series,
or combinations thereof, but the basic purpose is to minimize objection-
able oversize and develop a product fineness best suited for effective
combinations in the kiln.
This finished finely ground raw mix is conveyed by pneumatic pumps
or by mechanical means to blending, homogenizing, and/or storage silos
from which it is withdrawn as kiln feed.
Wet Process
Wet-process grinding uses ball mills or compartment mills that are
essentially the same as those used in the dry process except for feed-
ing and discharge arrangements. Water is added to the mill with the
crushed feed to form a slurry. Where clay is used as a raw material,
it is generally added in suspension as a slip. Grinding may be done in
one or two stages. Some installations are closed circuited with bowl-
rake classifiers that return the oversize to the mill as "sands" and dis-
charge the finished product as a very dilute overflow. Excess water in
this overflow is removed in thickeners.
In other plants, mills are closed circuited with cyclones or screens
that produce a final more viscous slurry that does not require thick-
eners. The various crushed materials may be proportioned ahead of
grinding, as in the dry process, or each major component may be ground
into separate slurries that are then proportioned and blended. Finished
slurry fed to kilns may contain 30 to 40 percent water, or it may be fur-
ther de-watered in vacuum filters and fed to the kiln as a "cake" con-
taining about 20 percent water."7
CLINKER PRODUCTION
Clinker production is one of the most important functions in a cement
plant; the quality of the finished cement largely depends upon proper
burning conditions in the kiln.
MANUFACTURE OF PORTLAND CEMENT 11
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The rotary kiln used in most plants in the United States is a steel
cylinder with a refractory lining. Kilns may be 6 feet in diameter by
60 feet in length (a size almost extinct) to as large as 25 feet in diame-
ter by 760 feet in length. The kiln is erected horizontally with a gentle
slope of 3/8 to 3/4 inch per foot of length, and rotates on its longitudi-
nal axis.
The kiln feed, commonly referred to as "slurry" for wet-process
kilns or "raw meal" for dry-process kilns, is fed into the upper end of
the revolving sloped kiln. As the feed flows slowly toward the lower
end, it is exposed to increasing temperatures. During passage through
the kiln (1 to 4 hours), the raw materials are heated, dried, calcined,
and finally heated to a point of incipient fusion at about 2,900° F, a tem-
perature at which a new mineralogical substance called clinker is pro-
duced. At the lower end of the kiln, the combustion of coal, fuel oil, or
gas must produce a process temperature of 2,600° to 3,000° F. The
combustion gases pass through the kiln counterflow to the material, and
leave the kiln, along with carbon dioxide driven off during calcination,
at temperatures of 300° to 1,800° F, depending on the kiln length and
the process used.
In the grate preheater system or "semidry" system, which was de-
veloped in Europe as the Lepol system, the feed is composed of raw
meal mixed with 10 to 12 percent water and is formed into pellets of
about 1-inch maximum size. These pellets are dried and preheated on
a slowly traveling grate through which the hot gases from the rotary
kiln are passed. The pellets are then fed directly into the rotary kiln.
As the hot waste gases pass through the kiln exit, they are some-
times utilized in preheat systems. These preheat systems can affect
the quantity of emissions released from the kiln. The grate preheater
method uses a double-pass system whereby the gaseous effluents pass
countercurrently through the wet (12 percent water) mix twice: first
to preheat the mix and second to dry and partially calcine the mix.
The suspension preheater system has been adapted to short, dry-
process kilns. In this system, the dry mix is preheated by direct con-
tact with waste gases in a multistage cyclone-suspension process. The
waste gases pass through one or more cyclones through which the mix
passes countercurrently.
Two basic types of wet-process kilns are in use in the United States.
Around 1930, short wet-process kilns were installed with waste-heat
boilers similar to the waste-heat boilers in the short (250 feet) dry
kilns. Shortly thereafter, the construction of short wet-process kilns
yielded to the building of long (350 feet) wet-process kilns with internal
chain preheaters. Most of the new wet-process kilns utilize a chain sys-
tem to heat and convey the feed. The system consists of a large number
of chains suspended in the drying zone of the kiln and so arranged that
in addition to lifting the slurry into the path of the hot gases, they con-
vey the raw material to the burning zone. The feed on the large exposed
surface of the chains is in intimate contact with the combustion gases.^
12 ATMOSPHERIC EMISSIONS FROM THE
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As the clinker is discharged from the lower end of the kiln it is
passed through a clinker cooler that serves the dual purpose of reduc-
ing the temperature of the clinker before it is stored and recovering
the sensible heat for reuse inside the kiln as preheated primary or
secondary combustion air. Rotary, planetary, vibrating, or grate type
air-quenching coolers are used to permit a blast of cooling air to pass
through a slowly moving bed of hot clinkers. The cooled clinker is then
conveyed by drag chains, vibrating troughs, or conveyor belts to storage.
FINISH GRINDING AND PACKAGING
In the final stage of cement manufacture, the clinker is ground into
cement. Interground with the clinker is a small amount of gypsum (4 to
6 percent), which regulates the setting time of the cement when it is
mixed with water and aggregate to make mortar or concrete.
Various grinding circuits are in use. The system may be two stage,
with preliminary and secondary mills, or the entire process may be
performed in a single compartment mill. Ball mills or tube mills
normally are used. Crushers may be used ahead of the ball or tube
mills. The grinding system may be open circuit, but most of the mills
are closed-circuited with air separators. The final product has a fine-
ness of 90 to 100 percent minus 325 mesh. The average size of a ce-
ment particle reportedly is about 10 microns. The finished cement is
transported by screws, belt conveyors, or pneumatic pumps to silos for
storage until it is shipped.
Some portland cement is packaged in 94-pound bags, which is one-
quarter of the 376-pound "barrel." In bulk, however, most cement is
transported in trucks, hopper cars, railway box cars, barges, and ships.
EMISSIONS AND THEIR CONTROL
Particulate matter is the primary emission in the manufacture of
Portland cement. There are also the normal combustion products of the
fuel used to supply heat for the kiln and drying operations, including
oxides of nitrogen and small amounts of oxides of sulfur.
For dust control, the cement industry generally uses mechanical col-
lectors, electrical precipitators, and fabric filter (baghouse) collectors
or combinations thereof, depending upon the emission and the tempera-
tures of the effluents in the plant in question and the particulate emis-
sion standards in the community. Gaseous emissions are controlled
only when an odor problem arises.
CRUSHING
Dust production in the crusher area depends on the type and moisture
content of the raw material, and the characteristics and type of crusher.
If the material has a high moisture content, it may not be necessary to
MANUFACTURE OF PORTLAND CEMENT 13
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provide dust control for plants located in a relatively isolated location.
Where dust generation from crushing is a problem, the entrained dust
is normally collected by centrifugal collectors or cloth filters. In some
cases dust-suppressive aqueous solutions are applied to control dust in
the crushing circuit.
In the process of conveying the crushed material to storage silos,
sheds, or open piles, dust is generated at various conveyor transfer
points. A hood is normally placed over each of these points to control
particulate emissions (see Figure 4). A face velocity of 200 feet per
minute is normally necessary to control the dust emitted at the trans-
fer points.9 Cloth filters have been used extensively and are very effec-
tive in recovering the dust.
Figure 4. Arrangement of dust collectors at transfer points of belt conveyors
and screw conveyors.
Storage silos are under slight pressure as a result of material dis-
placing air during the filling operation. In modern installations dis-
placed dust-laden air is normally vented to a bag-type dust collector.
This is especially true for silos with pneumatic loading and circulating
systems.
Where sheds are used for the storage of raw materials, and dust
emission is a problem, they should be as completely enclosed as pos-
sible. Dust-suppression methods on open or semi-open piles include
spraying the pile with water or dust-suppressive aqueous solutions,
(e.g., wetting agents or detergents), discharging the contents of the' con-
veyors onto the piles through telescoping spouts close to the top of the
pile rather than with a long free fall, and placing wind breakers such as
trees and fences around the piles.
14
ATMOSPHERIC EMISSIONS FROM THE
-------
RAW DRYING AND GRINDING - DRY PROCESS
The hot gases passing through a rotating cylindrical dryer will en-
train dust from the limestone, shale, or other materials being dried.
The concentration of dust in the exit gases is related to the velocity of
the gases, the quantity and size of the fine particles, and their degree of
dispersion in the gas stream. A heavier dust concentration may be ex-
pected in dryers utilizing kiln exit gases (waste-heat dryers) because of
the dust carry-over from the kilns.
Dust concentrations of 5 to 10 grains per cubic foot of rotary-dryer-
discharge gas prior to treatment can normally be expected.10 In one
example, data for two tests of an older dryer showed 13,000 cubic feet
per minute of exit gas at 200° F, carrying 6.0 grains per cubic foot.11
In another case, a number of rotary dryers discharged exit gases through
individual multicyclones followed by a common electrostatic precipita-
tor. Tests indicated 150,000 cubic feet per minute at 150° F discharged
from the precipitator with inlet and outlet loadings of 3.50 and 0.20 par-
ticulate grains per cubic foot, respectively. This is equivalent to 94.2
percent collection efficiency of the electrostatic precipitator. At an
estimated collection efficiency of 70 percent for the multicyclones, the
3.5 grains per cubic foot loading discharged by them is equivalent to
11.8 grains per cubic foot loading in the dryer discharge gases.12 The
type of dust control equipment used at this plant would be considered
adequate in that the gases from the drying - grinding operation were
processed through a multicyclone followed by an electrostatic precipi-
tator. In this particular case, however, the combined collection effi-
ciency of the multicyclone and precipitator was not sufficient to preclude
a dust nuisance problem in a residential area 1 mile downwind from the
cement plant. A design for greater dust collection efficiencies could
have precluded this problem.
The rotary dryer, like the rotary kiln, is a major source of dust gen-
eration in a cement plant and requires collecting systems designed for
higher temperatures. Systems in common use generally include multi-
cyclones or other type mechanical collectors, electrostatic precipitator
or combinations thereof. Where cloth filters are applied to drying op-
erations, they must be the glass-fiber type suitable for temperatures
above 250° F.
The most common dry grinding circuits, whether they use ball mills,
compartment mills, or vertical units, are vented from mill discharge
points to provide some air sweep through the mills to prevent mill
dusting during grinding. In the normal closed circuits, vents may also
be connected to mill discharge elevators, conveyors, and air separators
to maintain the entire system under negative pressure. The heavily
dust-laden air from these vents is conducted to dust-collecting appara-
tus, generally low temperature cloth filters.
Dusts collected from mill systems, raw or finish transfer points,
and conveyors present only minor air pollution problems as these are
MANUFACTURE OF PORTLAND CEMENT 15
-------
essentially closed systems and the dust collected is returned into the
unit from which it was collected, or to the mass of material in transit
at the appropriate stage of the process.
Data on dust loading from mill vent circuits are not readily available,
but the loading may be considered extremely high. One test on a verti-
cal ring roller mill showed an exit dust loading of 50 grains per cubic
foot at 139° F in a gas flow of 1,460 cubic feet per minute. These data
are of only academic significance, however, because the low tempera-
ture cloth collectors used for this service, when properly maintained,
will essentially collect 99.9 percent of the dust--which is returned to
the circuit. For extremely heavy dust concentrations, pre-cleaning
cyclonic collectors are normally used ahead of and in series with the
cloth filters.
In the case of "dry-in-the-mill" combination drying and grinding cir-
cuits, the final vent from the drying or closed-circuit separator or cy-
clone would be treated similarly with cloth filters or with electrostatic
precipitators in cases where moisture content of gases is too great to
assure operation of the filters above the dew point. Dust-collector gas
volumes for ginding circuits depend on the productive capacity and type
of circuit; they range from 2,500 to 50,000 cubic feet per minute per
unit.
RAW GRINDING WET PROCESS
Inasmuch as the raw materials are not dried, but are ground in the
presence of water as a slurry, no dust is generated.
KILN OPERATION
The largest source of emissions within cement plants is the kiln oper-
ation, which may be considered to have three units: the feed system, a
fuel-firing system, and a clinker-cooling and handling system. The kiln
itself (fuel-firing system) has three functions: drying, calcining, and
clinkering.
While the same general objective prevails with a closed system for
return of collected dust to the kiln, the complications of kiln burning and
the larger volumes of material to be handled have led to many systems
of dust collection and return.
Attention has been given to containing within the kiln some portion of
the dust generated. This may range from simple dust curtain chain sys-
tems (a dense curtain of light-weight chain hung close to the kiln exit)
to still highly experimental closed systems of fluidized bed calcination
sintering of clinker. Enlargement of the kiln diameter at the feed end,
which reduces gas velocities, improves the situation slightly by entrain-
ing less dust in the emitting gases. Most modern kilns are so con-
structed.
16 ATMOSPHERIC EMISSIONS FROM THE
-------
Modifications of a rotary kiln system or the addition of a suspension
preheater that uses cyclones or moveable grate preheaters are partially
effective in controlling dust generated in the kiln. Additional control
equipment such as cyclone collectors and electrostatic precipitators,
fabric filters, or scrubbers are normally used for satisfactory collec-
tion of kiln dust.
The most desirable method for disposing of the collected dust is to
return it to the kiln. The alkali content of the cement product, however,
must often be less than 0.6 percent by weight (calculated as sodium).
Where the alkali content of the raw material going into the kiln is high,
e. g. greater than 1 percent sodium and potassium feldspar, then leaching
of the collected dust may be required to reduce the alkali content in
order to return the dust to the kiln. Methods of returning dust to the
kiln are:
1. Direct dust return to kiln feed prior to kiln entry by mixing dry
dust and kiln feed either wet or dry.
2. Direct dust return to the kiln parallel to the kiln feed either wet
or dry.
3. In multiple kiln installations, collection of all dust from the group
of kilns for use as dry kiln feed for a single kiln.
4. Dust return by scoop feeders located in front of the chain system
as dry dust usually on a wet process kiln.
5. Leaching systems where the collected dust is mixed with large
volumes of water and then dewatered by thickener or mechanical
filters or centrifuges to remove water soluble alkalies. The re-
sultant slurry of reduced alkali dust may subsequently be remixed
with kiln feed, introduced parallel to kiln feed, spray impinged
onto the chain system, or in some cases used as slurry for wet
process raw milling. The leaching process has been applied to
collected dust from both wet and dry process kilns when low alkali
requirements are mandatory, when raw materials are alkali bear-
ing, and when high-efficiency dust collection systems entrap the
alkalies in the emission gases.
6. Insufflation, which is the return of dry dust into the burning zone
either through the fuel pipe, as is frequently the case in coal fired
kilns on unit coal pulverizers, or by a separate pipe parallel to
the burner pipe. Here the dust entering the burning zone sinters
into small grains of clinker and is discharged with the clinker to
the cooler. In this process the collected dry dust is usually
pumped from the collecting unit at the feed end to the burner floor
and into the burning zone through the kiln hood.
There is no one satisfactory method of returning the collected dust to
the kiln; as a result, to control alkalies or improve kiln operation, part
of the dust is disposed of in other ways.
MANUFACTURE OF PORTLAND CEMENT 17
-------
Disposal of dust, unless it can be sold as a substitute for agricultural
limestone, fertilizer, or as a mineral filler, presents problems. Since
the collected dust may range from a few hundred pounds per hour to
many tons, disposal requires a waste area and a means of moving dust
from the collector to the waste area. The collected dust may be mixed
with water and pumped to waste ponds in a manner similar to fly ash
disposal commonly practiced in power generating stations. It may be
dry pumped or truck hauled to worked-out quarry areas where rain and
weather concrete the disposal pile into a monolithic mass. Where open
truck haul to waste is practiced, usually the dust is dampened in a pug
screw as it is discharged into the truck.
If multistage dust collectors are installed on a kiln, it is common to
return the first stage or stages to the kiln and discard the final stages.
Because the alkalies tend to concentrate in the final stage (the finest-
size particle of dust), low alkali cement can be produced with minimum
dust disposal.
Gaseous Emissions
Gaseous emissions from the combustion of fuel in the kiln are usually
not sufficient to create significant air pollution problems. Most of the
sulfur dioxide formed from the sulfur in the fuel is recovered as it com-
bines with the alkalies and also with the lime when the alkali fume is
low.13'1 Tests of the kiln exit gases from one portland cement plant
burning 2.8 percent sulfur coal showed a concentration of sulfur dioxide
ranging from 6 to 39 parts per million.15 Nitrogen oxides can form at
kiln temperatures of 2,600° to 3,000° F, and may be of some concern
in areas that experience photochemical-type air pollution. Odoriferous
hydrogen sulfide and polysulfides may also be produced in the drying of
the slurry or in the drying of the dry-process raw material when the
latter is composed of marl, sea shells, shale, or clay. No data on the
amount of nitrogen oxides or polysulfides produced are available at this
time.
Particulate Concentrations Before Dust Collectors
To determine an average particulate emission rate for kiln opera-
tions is often impractical because of the diversity of kiln sizes, firing
rates, types of preheaters and clinker coolers, and feed characteristics
(wet or dry). Different types of feed composition also affect emission
rates. In fact, one of the most important causes of dust emissions is
the way in which gases are liberated and expelled from the raw feed
during the calcination of limestone. Some raw materials remain rela-
tively calm while the liberated gases escape; others appear to expand
and explode, throwing the material into the gas stream. This may ex-
plain why some wet-process plants have a higher dust loss than some
dry-process plants.-^
18 ATMOSPHERIC EMISSIONS FROM THE
-------
Ranges of particulate emission rates for kiln operations are presented
here along with generalized emission rates for certain specific kiln oper-
ations. The two basic processes, wet and dry, and the grate preheater
or semi-dry process are discussed.
Dry Process
Data are presented in Table 4 for the following three basic types of
dry-process kilns: 1) the short rotary kiln with or without a waste heat
boiler, 2) the suspension preheater system, and 3) the long rotary kiln
without a built-in preheater.
The concentration of dust leaving the kiln and entering the dust collec-
tion systems for all of the dry-process kilns ranged from 1.1 to 12.4
grains per cubic foot. The arithmetic average concentration for all
tests was 6.4 grains per cubic foot. No appreciable difference in the
range of dust loadings was apparent for the different types of dry-process
kilns.
The amount of dust in the exit gases from dry-process kilns ranged
from 1 to 25 percent expressed in terms of the finished cement, or from
4 to 94 pounds per barrel. The arithmetic average for dust loading in
the kiln exit gases is 11.3 percent of the equivalent finished cement based
on available data for nine dry-process kilns. Note that several kilns are
considerably below and above this figure. The average weight of dust
collected from the kiln exit eases per barrel of clinker has been reported
by Kannewarf and Clausen1" to be 48.1 pounds. This value would be
equivalent to 46 pounds of dust per barrel of finished cement if 5 percent
of the finished cement was gypsum.
Wet Process
Emission and operating data for the wet rotary process kilns are
shown in Table 5. The concentrations of dust leaving the kilns and
entering the dust collection systems ranged from 0.995 to 13.51 grains
per cubic foot for all of the wet-process kilns. The arithmetic average
for all tests was 5.7 grains per cubic foot. Again, no appreciable dif-
ference in the range of dust leadings is apparent for kilns of different
lengths.
The amount of dust in the exit gases from wet process kilns ranged
from 1 to 33 percent of the finished cement. This is equivalent to 4 to
124 pounds per barrel. The arithmetic average for dust loadings in the
exit gases from the 13 wet-process kilns is 10.1 percent of the equiva-
lent finished cement. This is slightly lower than the average for dry-
process kilns despite the abnormally high values for plant 21. According
to Kannewarf and Clausen1^ the average weight of dust collected per
barrel of clinker is 39.8 pounds. This is equivalent to about 38 pounds
of dust per barrel of finished cement.
MANUFACTURE OF PORTLAND CEMENT 19
-------
Table 4. EMISSION AND OPERATING DATA FOR DRY-PROCESS ROTARY CEMENT KILNS AND DUST COLLECTORS
Feed preheat method3
Kiln length, feet
Number of kilns per test
Number of tests averaged
Total production rate, bbl/day
Stack gas volume, 1,000 cfm
Stack gas temperature, °F
Method of dust collection,13 primary
secondary
Inlet dust loading, grains/ft3
{stack conditions)
Outlet dust loading, grains/ft3
(stack conditions)
Outlet dust loading, grains/ft3
(60°F)
Outlet dust quantity, Ibs/day
Dust collector catch, Ibs/day
primary
secondary
Dust collector efficiency, percent
primary
secondary
overall
Dust loss before collection,
percent clinker
Dust emission, percent product
W0tle S"P N°ne None None None DP Cross None None None None None None
140 15° 323 314 380 150 118 400 365 125 400 125
200
2 1 1
113 - 2 1 1 1 10 1 1
33 - 1 31213 2
4,000 1,880 5,260 9,580 4,800 2,150 3,800 1,668 6,100 3,300 504 2,900 2,750
48'7 40'4 202-° 300.0 196.6 - 233.7 104.9 421.0 129.0 40.3 122 125
5 375 50° 500 510 150 200 467 497 565 550 845 600 560
WHB MC , Much MC MC MC MC MC
Mc £p MC ™ Hone EP
Bag EP EP EP EP EP
6'91 7'01 8.61 5.51 9.69 12.43 - - 1.H6 1.6 8.5 2.41
°'23 0'84 i-66 0.02 0.47 - 0.041 0.084 0.022 0.684 2.41 0.013 0.136
ll95 0'37 '-55 3-06 0-039 0.55 - 0.073 0.154 0.043 !.3 6.05 0.0265 0.267
8l™ 2l2SO 9'3M 67'9°0 1,264 19,000 2,830 1.970 1,790 1,910 18,216 20,280 326 3,500
M'2°° 430,000 300,000 - 63 600 - - -
68,000 62,200 161,000 9d nfl-, T, A*n
nr rinf. ^4,083 1J.400
' 167,000 183,000 - - 144,000
30 - TT
„ , ~ - 71 60 - - 77.7 - -
~ 86.9 70.2 99.3 90 6 63 5
81'9 96'8 86-9 ™.2 =3-8 %.2 - - 93.0 98.6 SI. 3
4'9 10'7 1Z'2 "-5 29.3 - _ ,.35 O.TOS 27.6 n.3
°'151 ^^ 3-43 O'0351 1-04 0.35 0.138 0.286 0.083 1.47 10.7 0.03 0.34
18 I2 19 28 28 28 28 28 28 28
-------
Table 5. EMISSION AND OPERATING DATA FOR WET-PROCESS ROTARY CEMENT KILNS AND DUST COLLECTORS
Test number 1 2
Feed preheat method3- None
Kiln length, feet 160 350
Number of kilns per test 3 4
Number of tests averaged 2 1
Total production rate, bbl/day 3,980 5,000
Stack gas volume, 1,000 cfm 155.0 186,0
Stack gas temperature, "F 363 290
Percent moisture In stack
gas (volume percent)
Method of dust collection13
primary
EP
secondary EP#1&2
Inlet dust loading, grains/ft3
(stack conditions) 6.50 J-.97
Outlet dust loading, grains /ft3
(stack conditions) 0.22 0.15
Outlet dust loading, grains/ft3
(60°F) 0.35 0.22
Outlet dust quantity, Ibs/day 6,940 5,720
Dust collector catch, primary
Ibs/day 200,000 69,500
secondary
Dust collector efficiency, primary
percent secondary 96. 5 96-90
overall 96.5 92.4
Dust loss before collection,
percent clinker 14.6 4.2
Dust emission,
percent product 0.463 0. 304
Reference 17 21
3 4 5 G 7 3
CB,C -
460 310
1 1141 1
1 2222 4
4,500 - 2,200
146.0 72.2 97.5 72.4 155.9 98.6
320 293 390 450 450 550
36.8 37 29 20 32.5 25-30
MC
Bag EP EP EP EP
EP
.1.1.75 8.47 3.21 3.77 4.99 3.63
0.0098 0.0220 0.0520 0.0194 0.0434 0.0648
0.0148 0.0360 0.0850 0.0339 0.0760 0.126
296 327 1,042 289 1,391 1,314
75,400 70,000
307,000 55,800 161,000 72,300
49,900 45,400
_
99.9 99.74 99. 1 99.49 99.13 98.21
19.1 - 9.4
0.0175 - - - - 0.159
22 23 23 23 23 23
9 10
None
2@380
2@220
1 4
3 8
7,500
155.5 445.0
550 350
25-35
EP EP
3.14,3,31;
11.44 7.21,8.28
0.104 0.469
0.211 0.730
3,383 14,000
-
357,000
"
-.
99.05 97,73
^
0.497
23 28
11 12 13 14 15 16 17 18 19 20 21 22
None C C C C,CB -
475 425 300-425 300-425 423 425 175 600
4 - - - 1 2 3 3 2 1 31
34244411
5,600 2,500 1,900 3,475 3,900 7,067 6,250 7,600 6,861 3,600 2,825 8,269
277.0 141.5 95.0 166.5 84-4 229.9 207.5 448.3 369.8 152.8 209.0 279.0
355 385 450 330 285 343 525 460 450 547 352 390
40.3 36.7 30.2 23.7 35.0 22.9 35.6
MC
EP EP EP EP EP EP EP EP EP EP EP
EP
4.6 0.995 5.28 1.49 3.86 13.51 1.80 4.03
0.091 0.390 0.250 0.069 0.022 0.058 0.030 0.0695 0.034 0.108 0.070 0.028
0.1425 0.634 0.485 0.105 0.032 0.089 0.057 0.123 0.053 0.208 0.110 0.046
5,260 11,400 4,930 2,350 384 2,725 1,296 6,425 2,332 3,395 3,024 1,622
_
44,260 224,000 130,570 291,350 421,630 74,280 229,680
99. 51 94. 2 99.4 95.4 99. 2 99. 17 96. 1 99. 3
5.8 1.8S 10.0 5.0 j.1.9 33.0 7.6 7.7
0.25 1.21 0.69 0.18 0.0261 0.1025 0.551 0.225 0.09 0.250 0.285 0.052
28 28 28 28 28 28 28 28 28 28 28 28
1 C = Chain; CB *= Cross-baffle.
3 MC - Multicyclones; EP - Electrostatic precipitators; Bag = Glass fabric baghouse.
-------
EVALUATION OF DUST CONTROL EQUIPMENT AS IT AFFECTS KILN
EFFLUENT
The data in Tables 4 and 5 show that dust collection equipment is
necessary on all cement kilns in the United States. The method and
degree of control vary with the type of plant and its location. Ranges of
dust emissions from control systems serving wet- and dry-type cement
kilns are shown in Table 6.
Table 6. RANGES OF DUST EMISSIONS FROM CONTROL
SYSTEMS SERVING DRY- AND WET-TYPE CEMENT KILNS
Source
a
Kiln- dry type
b
Kiln-wet type
Type of dust collector
Multicyclones
Electrical
precipitators
Multicyclone and
electrical
precipitators
Multicyclone and
cloth filter
Electrical
precipitators
Multicyclone and
electrical
precipitators
Cloth filter
Range of dust emissions from collector
grain /scfc
1.55 - 3.06
0.04 - 0.15
0.03 - 1.3
0.039
0.03 - 0.73
0.04 - 0.06
0.015
Ib/ton of cement
26.2 - 68.6
1.7 - 5.7
0.6 - 29.4
0.7
0.52 - 9.9
4.3 - 24.2
0.35
aBased on data from Table 4.
bBased on data from Table 5.
cGrains/scf Grains per standard cubic foot of
gas corrected to 60°F and 1 atmosphere pressure.
It is recommended that the particulate matter be collected by a high-
efficiency collector because of the small particle size of the emitted
dust (see Table 7). As much as 55 percent of the kiln dust particles may
be smaller than 10 microns.
22
ATMOSPHERIC EMISSIONS FROM THE
-------
Table 7. EXAMPLE OF SIZE DISTRIBUTION OF DUST
EMITTED FROM KILN (Reference 24)
Particle size,
micron
60
50
40
30
20
10
5
2.5
Kiln dust finer
than respective particle size,
%
97 to 100
95 to 100
85 to 95
70 to 90
50 to 70
30 to 55
20 to 40
10 to 35
Although a number of types of dust collectors are used in the cement
industry, only the high-efficiency collectors such as the electrostatic
precipitator and fabric filter, sometimes used in series with inertial
collectors, effectively collect fine dust. The 60 to 87 percent efficiency
of the multicyclone collector results in a minimum grain loading of 1.55
grains per standard foot (Table 4). Consequently, the multicyclone alone
is not an acceptable means of reducing dust emission from the kiln to
the atmosphere.
Electrostatic precipitators or glass-fabric filters, sometimes pre-
ceded by mechanical collectors, are necessary to reduce emissions to
a satisfactory level. Results (Tables 4 and 5) of tests made on inlet and
exit ducts of older electrostatic precipitation units indicate that even
though precipitator efficiencies of 96 to 97 percent are obtainable on
large volumes of kiln gas the exit grain loading may still range from 0.2
to 0.3 grains per standard cubic foot. Although these emission rates
may be acceptable in nonurban areas, they would probably result in dust
nuisance problems if located in or near urban areas. New, well designed
and maintained precipitators can remove 99 plus percent of the dust
loading (Test 15, Table 5), and reduce grain loading to 0.05 grains per
standard cubic foot. At least two manufacturers guarantee at least 99.5
percent collection efficiency.20,25
Glass-fabric filters can reduce dust loading 99.5 plus percent, or
below 0.02 grains per standard cubic foot. Figures 5 and 6 show a fab-
ric filter installation. These collectors can reduce the plume to less
than 10 percent equivalent opacity when properly maintained. One test
(Test 3, Table 5) with a kiln that utilized a glass-fabric baghouse shows
grain loadings as low as 0.01 grains per cubic foot.
Although some plants have experienced problems from moisture con-
densation in glass-fabric filters, other plants have been successful in
precluding this condition. Dewpoint temperatures in glass-fabric col-
MANUFACTURE OF PORTLAND CEMENT 23
-------
lectors are normally avoided by proper application of insulating mate-
rial on drop-out hoppers, ducting, fan casings, and compartment sepa-
rators. When it is necessary to shut a kiln down for repairs, the forced
draft fan and baghouse should be kept operating to keep air moving
through the fabric filters and thus avoid condensation.^6
Figure 5. Feed end of rotary kilns showing multicyclone dust collectors,
draft fans, and stacks.
The data in Tables 4 and 5 indicate that high-efficiency electrostatic
precipitators, glass-fabric baghouses, or mechanical collectors followed
by precipitators or baghouses can lower dust grain loadings to below
0.05 grains per standard cubic foot. Data illustrating the dust grain
loadings and dust collection efficiencies needed to meet particulate emis-
sion limitations based on process weight are presented in Table 8.
TABLE 8. ESTIMATED DUST GRAIN LOADINGS AND COLLECTION
EFFICIENCIES NEEDED TO MEET SELECTED EMISSION REGULATIONS
Capacity of
kiln,
bbl/day
2,000
2,000
4,000
4,000
6,000
6,000
8,000
8,000
Type
of
fuel
coal
oil or gas
coal
oil or gas
coal
oil or gas
coal
oil or gas
Process weight,
raw material
plus solid fuel,
Ib/hr
57,600
50,000
115,000
100,000
173,000
150,000
230,000
200,000
Allowable dust
emission rate,
Ib/hr
La Bb
38.6 38.6
34.3 35.4
40.0 45.8
40.0 44.6
40.0 44.9
40.0 48.5
40.0 52.6
40.0 51.2
Approximate dust
grain loading to
meet ordinance,
grains/scf
La Bb
0.08 0.08
0.08 0.08
0.05 0.06
0.05 0.05
0.03 0.04
0.03 0.04
0.02 0.03
0.02 0.03
Approximate dust
collection efficiency
needed to meet
ordinance, %
La Bb
98.3 98.3
98.5 98.4
99.6 99.6
99.6 99.6
99.7 99.6
99.7 99.6
99.8 99.7
99.8 99.7
a Los Angeles Air Pollution Control District.
b Bay Area Air Pollution Control District (San Francisco).
c Grains per standard cubic foot at 60° F and 1 atmosphere pressure.
24
ATMOSPHERIC EMISSIONS FROM THE
-------
These data are based on averaged emission and gas-flow information
from Tables 4 and 5, applied to particulate emission limitations for Los
Angeles and the Bay Area (San Francisco) Air Pollution Control Dis-
tricts.
Figure 6- Inside of baghouse dust collector showing siliconized glass-fiber
bags m position.
Approximate dust-grain loadings needed to meet these California
ordinances vary from 0.08 grain per standard cubic foot for small kilns
(i. e., 2,000 barrels per day capacity) to 0.02 grain per standard cubic
foot for large units (i. e., 8,000 barrels per day capacity). The approxi-
mate corresponding dust collection efficiencies range from 98.3 percent
for small kilns to 99.8 for large units. Kilns of up to 4,000 barrels per
day capacity could meet the process weight limitations for Los Angeles
and for the Bay Area with exit dust loadings of 0.05 grains per standard
cubic foot. A dust collection efficiency of approximately 99.6 percent
would be required, however. For large kilns (8,000 barrels per day)
lower exit dust loadings of 0.02 to 0.03 grain per standard cubic foot
would be required to meet the emission regulations of Los Angeles and
of the Bay Area, respectively.
GRATE PREHEATER PROCESS
Although the grate preheater is used presently by only two plants in
the United States, it is briefly discussed here because of its low emis-
sion rates. The advantages of the grate preheater system are twofold:
first, the fuel requirement is approximately 30 to 40 percent less than
that for the other long-dry-process kilns; and second, expressed in
terms of finished cement, the kiln dust losses are equivalent to only
0.05 to 1.0 percent. ' Test 7 in Table 4 shows data on the grate pre-
MANUFACTURE OF PORTLAND CEMENT
25
-------
heater process that utilized no dust collection equipment. For the three
tests, the dust emissions averaged only 0.35 percent of the cement clinker.
Application of the grate preheater process is often limited to raw mate-
rials with low alkali values.
CLINKER-COOLER EMISSIONS
The clinker coming from the kiln is normally cooled in rotary-drum,
shaking, inclined, horizontal, or traveling grate coolers. Cooling air
induced through the rotary-drum cooler may be utilized in the kiln as
secondary combustion air, whereas air drawn through the grate cooler
can only be partially used as secondary combustion air. The excess
air from the grate cooler can be used for drying purposes, or it can be
discharged to the atmosphere; before discharge to the atmosphere, the
excess air passes through a mechanical collector that is very effective
in removing the clinker dust, which is normally of large particle size.
Only 10 to 15 percent of cement clinker-cooler dust is below 10 microns
in size.
FINISHING AND SHIPPING
Clinkers are ground in the same type of mills in which raw materials
are ground. The discharge from these mills is elevated to an air sepa-
rator in closed-circuit grinding. The cement with the proper fineness
is sent to storage, and the oversize is sent back to the mill for regrind-
ing. The circuit may be cooled by air passing through the mill and sepa-
rator and into a fabric-filter dust collector.
Cement-material handling (such as pneumatic conveying of finished
material, bagging, and bulk loading) is a potential source of dust emis-
sions. The high salvage value of the escaping material makes dust col-
lection an economic necessity. Almost all dust control equipment is of
the fabric-filter type. Normally material transfer points are hooded,
which prevents escape of most of the dust.
Although most plants adequately control emissions from their finish-
ing and shipping operations by the methods mentioned, some plants still
emit dust. These emissions may create extreme nuisances, not only at
cement plants but also at cement distribution centers.
TRENDS
The manufacture of portland cement has changed enormously in the
past several decades. The cement industry of the past produced 0.45
ton of clinker per ton of raw material at a fuel-use rate of 1.5 million
Btu's per barrel of cement. Today the same capacity plant produces
0.60 to 0.65 ton of clinker per ton of raw material at a fuel-use rate of
less than 1 million Btu's per barrel.29
26 ATMOSPHERIC EMISSIONS FROM THE
-------
Although emissions from many plants have been partially or wholly
controlled, a few older plants still discharge as much as 3 percent of
their kiln product into the atmosphere. These older plants are gradually
being replaced with new, modern plants that utilize larger units; the
resulting fewer emission points are equipped with high-efficiency dust-
emission-control equipment.
Cloth filter bags adequately clean the gases drawn from crushers,
grinders, dryers, and material transfer points. Glass-fiber filter bags
or electrostatic precipitators adequately clean the hot kiln gases.
Cement plants are expected to continue this modern trend toward
more efficient production through centralized and effective dust control.
Although the economic benefits resulting from the reuse of collected
dust do not completely offset the cost of the dust-collection equipment,
the esthetic value to the community plus a compliance with certain munic-
ipal and state air pollution control ordinances make these advances in
dust arrestment worthwhile.
ACKNOWLEDGMENTS
The authors are grateful for the assistance given them by many indi-
viduals and organizations. Appreciation is extended to Mr. R. Emmet
Doherty, Director of the Lehigh Valley Air Pollution Control Agency for
his generous contribution of knowledge and time in the review of this
report.
Grateful appreciation is also extended to the technical representa-
tives of several major portland cement manufacturing companies for
their valuable assistance in the review of this report and in supplying
needed emission and operating data.
MANUFACTURE OF PORTLAND CEMENT 27
-------
REFERENCES
1. Rick, R. Ed. Pit and Quarry Handbook and Purchasing Guide:
1964. 57th ed. Pit and Quarry Publications, Chicago, 111.
2. U. S. Bureau of the Census. Statistical Abstract of the United
States: 1962. 83rd ed. Washington, B.C. 1963.
3. Landsberg, H. H., L. L. Fischman, and J. L. Fisher. 1970-2000:
Medium Projections. Resources in America's Future. The Johns
Hopkins Press, Baltimore, Md. 1963.
4. Trauffer, W E. Cement. Pit and Quarry, pp. 86-110. January 1965,
5. Cement Production and Distribution. Map. Copyright Pit and
Quarry Publications. 1961.
6. Trauffer, W. E. Cement. Pit and Quarry. January 1963, January
1964.
7. Clausen, C. F. Cement Materials, Chapter 9 in: Industrial Min-
erals and Rocks. 3rd ed. American Institute of Mining, Metallur-
gical and Petroleum Engineers, New York. 1960.
8. Cement. Encyclopedia Britannica, Vol. 5, pp. 153-158. Copyright
1963.
9. Industrial Ventilation Manual. 3rd ed. American Conference of
Government Industrial Hygienists. 1964.
10. Personal communication from control equipment manufacturer.
October 1961.
11. Personal communication from control equipment manufacturer.
September 1965.
12. Personal communication from Stanley T. Cuffe, Division of Air
Pollution, U. S. Public Health Service, Robert A. Taft Sanitary
Engineering Center, Cincinnati, Ohio. March 15, 1965.
13. Personnal communication from Frederick A. Rohrman, Division of
Air Pollution, U. S. Public Health Service, Robert A. Taft San-
itary Engineering Center, Cincinnati, Ohio. April 23, 1965.
14. Plass, R. J., and H. H. Haaland. Electrostatic Precipitators in the
Cement Industry. Presented at the Electrostatic Precipitation Sem-
inar, Pennsylvania State University. June 16-21, 1957.
15. Personal communications from Canada Cement Company Limited,
Montreal, Quebec, Canada. June 9, 1966.
29
-------
16. Kannewarf, A. S., and C. E. Clausen. What Do You Know About
Cement Kilns? Rock Products. May 1962.
17. Personal communication from R. E. Doherty, Lehigh Valley Air
Pollution Control, Northampton, Pennsylvania. March 15, 1965.
18. Harrison, B. P., Jr. Baghouse Cleans 500°+Cement Kiln Gases.
Air Engineering. Vol. 5, pp. 14-16. March 1963.
19. Burnett, C. E., and E. C. Mertz. Progress of the ACL System.
Presented at the National Lime Association, Operating Division
Meeting, Austin, Texas. October 8, 1957.
20. Personal communication from Re search-Cottrell, Inc. September
3, 1965.
21. Wisconsin State Board of Health, State of Wisconsin. Cement Stack
Dust Study. Unpublished report. July 22, 1953.
22. Personal communication from cement plant official. April 23,
1965.
23. Personal communication from Koppers Company, Inc. September
10, 1965.
24. Burke, E., J. L. Murray, and K. R. Johnson. Practical Aspects of
Dust Control in the Cement Industry. In: Mechanical Engineers
Contributions to Clean Air, pp. 103-117. February 1957.
25. Personal communication from American-Standard, Industrial Divi-
sion. September 13, 1965.
26. Doherty, R. Emmet. Current Status and Future Prospects -
Cement Mill Air Pollution Control. Presented at the National Con-
ference on Air Pollution, Washington, D. C. December 12-14, 1966.
27. Cronon, C. S. Two U. S. Cement Mills Now Save Fuel, Avoid Dust
Losses with New ACL Calcining Systems. Chemical Engineering.
April 18, 1958.
28. Personal communications from cement plant officials. June 21,
1966.
29. Bergstrom, J. H. Cement Plants of the 60's. Rock Products.
May 1964.
30 REFERENCES
GPO 803—789-5
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APPENDIX
PORTLAND CEMENT ESTABLISHMENTS IN THE UNITED STATES
The main purpose of this tabulation of portland cement manufac-
tures is to indicate the wide distribution and the principal areas of con-
centration of this industry throughout the country. Information was
drawn from various sources, particularly Pit and Quarry magazine and
in some cases cement companies, and is believed to represent the in-
stallations operating as of September 1, 1966. As a result of sale, mer-
ger, or lease, company identifications may in some cases differ from
those presently in use, but this tabulation should serve the intended
purpose of general identification.
31
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PLANTS PRODUCING PORTLAND
CEMENT IN THE UNITED STATES
Capacities Stated in Barrels Per Year (1966).
ALABAMA
Birmingham
Alpha Portland Cement Co.
Wet process; 1,800,000 bbl.
Lehigh Portland Cement Co.
Wet process; 1,840,000 bbl.
Lone Star Cement Corp.
Wet process; 1,900,000 bbl.
Southern Cement Co.
Div. American-Marietta Corp.
Finish grinding plant - no
kiln operation
Ragland
National Cement Co.
Dry process; 1,500,000 bbl.
Roberta
Southern Cement Co.
Division American-Marietta Corp.
Dry process; 2,600,000 bbl.
ARIZONA
Demopolis
Lone Star Cement Corp.
Dry process; 1,500,000 bbl.
Leeds
Universal Atlas Cement Div.
U. S. Steel Corp.
Wet process; 2,000,000 bbl.
Clarkdale
Phoenix Cement Co.
Div. of American Cement Corp.
Dry process; 2,600,000 bbl.
Rillito
Arizona Portland Cement Co.
Dry process; 2,700,000 bbl.
Mobile
Ideal Cement Co.
Wet process; 2,800,000 bbl.
33
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ARKANSAS
Foreman
Arkansas Cement Corp.
Wet process; 2,800,000 bbl.
(5,000,000 bbl. in 1966)
Okay
Ideal Cement Co.
Wet process; 1,850,000 bbl.
CALIFORNIA
Colton
California Portland Cement Co.
Dry process; 4,500,000 bbl.
Davenport
Pacific Cement and
Aggregates, Inc.
Dry process; 2,800,000 bbl.
Lebec
Pacific Western Industries
Dry process; 3,000,000 bbl.
(To be completed in 1966)
Lucerne Valley
Permanente Cement Co.
Cushenbury Plant
Wet process; 5,400,000 bbl.
Monolith
Monolith Portland Cement Co.
Wet process; 4,000,000 bbl.
Pro Grande
Riverside Cement Corp.
Div. American Cement Corp.
Dry process; 6,500,000 bbl.
Permanente
Permanente Cement Co.
Wet process; 8,500,000 bbl.
Reddir
Calaveras Cement Co.
Dry process; 1,500,000 bbl.
Redwood City
Ideal Cement Co.
Wet process; 2,550,000 bbl.
Riverside
Riverside Cement Co.
Div. American Cement Corp.
Dry process; 4,750,000 bbl.
(gray)
Mojave
California Portland Cement Co.
Dry process; 6,000,000 bbl.
34
ATMOSPHERIC EMISSIONS FROM THE
-------
Riverside Cement Co.
Div. American Cement Corp.
Dry process; 650,000 bbl.
(white)
San Andreas
Calaveras Cement Co.
Wet process; 4,500,000 bbl.
San Juan Bautista
Ideal Cement Co.
Wet process; 950,000 bbl.
Victorville
FLORIDA
Bunnell
Lehigh Portland Cement Co.
Wet process; 3,350,000 bbl.
Miami
Southwestern Portland Cement Co.
Wet process; 6,000,000 bbl.
COLORADO
General Portland Cement Co.
Florida Division
Wet process; 2,500,000 bbl.
Lehigh Portland Cement Co.
Wet process; 2,500,000 bbl.
Tampa
General Portland Cement Co.
Florida Division
Wet process; 7,000,000 bbl.
Florence
Ideal Cement Co.
Wet and dry process;
2,150,000 bbl.
Fort Collins
Ideal Cement Co.
Dry process; 2,800,000 bbl.
GEORGIA
Atlanta
Southern Cement Corp.
Div. American-Marietta Co.
Dry process; 1,200,000 bbl.
Clinchfield
Perm-Dixie Cement Corp.
Wet process; 2,372,000 bbl.
Rockmart
Marquette Cement Mfg. Co.
Dry process; 1,250,000 bbl.
MANUFACTURE OF PORTLAND CEMENT
35
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HAWAII
Waianau, Honolulu
Permanente Cement Co.
Wet process; 1,700,000 bbl.
Oglesby
Marquette Cement Mfg. Co.
Dry process; 4,250,000 bbl.
Waipahu, Oahu
Hawaiian Cement Corp.
Dry process; 1,000,000 bbl.
Joppa
Missouri Portland Cement Co.
Dry process; 3,000,000 bbl.
IDAHO
INDIANA
Inkom
Idaho Portland Cement Co.
Wet process; 800,000 bbl.
Buffington
Universal Atlas Cement Div.
U. S. Steel Corp.
Dry process; 9,700,000 bbl.
ILLINOIS
Clarksville
Dundee Cement Co.
Wet process; 7,000,000 bbl.
(To be completed in 1966)
Dixon
Medusa Portland Cement Co.
Dry process; 3,500,000 bbl.
La Salle
Alpha Portland Cement Co.
Dry process; 1,500,000 bbl.
Greencastle
Lone Star Cement Corp.
Wet process; 2,700,000 bbl.
Logansport
Louisville Cement Co.
Wet process; 1,200,000 bbl.
(2,400,000 bbl. in 1966)
Mitchell
Lehigh Portland Cement Co.
Dry process; 2,500,000 bbl.
36
ATMOSPHERIC EMISSIONS FROM THE
-------
Speed
Louisville Cement Co.
Dry process; 5,250,000 bbl.
IOWA
KANSAS
Bonner Springs
Lone Star Cement Corp.
Wet process; 2,400,000 bbl.
Davenport (Linwood)
Chanute
Dewey Portland Cement Co. Ash Grove Lime and Portland
Div. American-Marietta Corp. Cement Co.
Wet process; 3,200,000 bbl. Wet process; 2,800,000 bbl.
Des Moines
Marquette Cement Mfg. Co.
Wet process; 4,500,000 bbl.
Mason City
Lehigh Portland Cement Co.
Dry process; 3,340,000 bbl.
Northwestern States Portland
Cement Co.
Dry process; 4,000,000 bbl.
West Des Moines
Penn-Dixie Cement Corp.
Wet process; 2,340,000 bbl.
Fredonia
General Portland Cement Co.
Victor Division
Wet process; 2,300,000 bbl.
Hum bolt
Monarch Cement Co.
Dry process; 2,400,000 bbl.
Independence
Universal Atlas Cement Division
U. S. Steel Corp.
Dry process; 2,200,000 bbl.
lola
Lehigh Portland Cement Co.
Wet process; 1,340,000 bbl.
MANUFACTURE OF PORTLAND CEMENT
37
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KENTUCKY
MARYLAND
Kosmosdale
Lime Kiln
Kosmos Portland Cement Co., Inc. Alpha Portland Cement Co.
Dry process; 4,000,000 bbl. Wet process; 2,250,000 bbl.
LOUISIANA
Baton Rouge
Ideal Cement Co.
Wet process; 3,000,000 bbl.
Lake Charles
Lone Star Cement Corp.
Wet process; 2,000,000 bbl.
New Orleans
Lone Star Cement Corp.
Wet process; 1,500,000 bbl.
Security
Marquette Cement Manufacturing Co.
Dry process; 2,200,000 bbl.
Union Bridge
Lehigh Portland Cement Co.
Dry process; 3,500,000 bbl.
MICHIGAN
Alpena
Huron Portland Cement Co.
Sub. National Gypsum Co.
Dry process; 13,800,000 bbl.
MAINE
Thomaston
Bay City
Aetna Portland Cement Co.
Div. American Marietta Corp.
Wet process; 8,800,000 bbl.
Dragon Cement Co.
Div. American-Marietta Corp. Cement City
Wet process; 2,000,000 bbl.
General Portland Cement Co.
Peninsular Div.
Wet process; 1,200,000 bbl.
38
ATMOSPHERIC EMISSIONS FROM THE
GPO 8O3—789—4
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Detroit
MISSISSIPPI
Peerless Cement Co.
Div. American Cement Corp.
Wet process; 3,700,000 bbl.
Peerless Cement Co.
Div. American Cement Corp.
Wet process; 1,800,000 bbl.
Dundee
Dundee Cement Co.
Wet process; 6,000,000 bbl.
Brandon
Marquette Cement Manufacturing Co.
Wet process; 1,300,000 bbl.
Redwood
Mississippi Valley Portland
Cement Co.
Wet process; 2,000,000 bbl.
Petoskey
Penn-Dixie Cement Co.
Wet process; 3,000,000 bbl.
Port Huron
Peerless Cement Co.
Div. American Cement Corp.
Wet process; 1,000,000 bbl.
MISSOURI
Cape Girardeau
Marquette Cement Mfg. Co.
Wet process; 1,200,000 bbl.
Marquette Cement Mfg. Co.
Dry process; 1,800,000 bbl.
Wyandotte
Wyandotte Chemicals Corp.
Wet process; 2,000,000 bbl.
Festus
River Cement Co.
Div. Missouri River and Fuel
Dry process; 3,000,000 bbl.
MINNESOTA
Duluth
Universal Atlas Cement Div.
U. S. Steel Corp.
Dry process; 2,000,000 bbl.
Hannibal
Universal Atlas Cement Div.
Wet process; 2,200,000 bbl.
(4,000,000 bbl. in 1966)
MANUFACTURE OF PORTLAND CEMENT
39
-------
Lemay
Alpha Portland Cement Co.
Wet process; 2,600,000 bbl.
Superior
Ideal Cement Co.
Wet process; 1,300,000 bbl.
St. Louis
Missouri Portland Cement Co.
Wet process; 5,000,000 bbl.
Sugar Creek
Missouri Portland Cement Co.
Dry process; 3,000,000 bbl.
NEVADA
New Fanley
Nevada Cement Co.
Dry process; 3,000,000 bbl.
MONTANA
Helena
Permenente Cement Co.
Wet process; 1,400,000 bbl.
NEW MEXICO
Tijeras
Ideal Cement Co.
dry process; 2,700,000 bbl.
Trident
Ideal Cement Co.
Dry process; 1,500,000 bbl.
NE BRASKA
Louisville
Ash Grove Lime and Portland
Cement Co.
Wet process; 3,500,000 bbl.
NEW YORK
Alsen
Lehigh Portland Cement Co.
Dry process; 2,650,000 bbl.
Buffalo
Lehigh Portland Cement Co.
Wet process; 2,340,000 bbl.
40
ATMOSPHERIC EMISSIONS FROM THE
-------
Cat skill
Kingston
Alpha Cement Co.
Wet process; 3,000,000 bbl.
Marquette Cement Mfg. Co.
Wet process; 2,500,000 bbl.
(3,300,000 bbl. in 1966)
Cementon
Alpha Portland Cement Co.
Dry process; 1,700,000 bbl.
Hudson Cement Corp.
Wet process; 4,000,000 bbl.
Ravena
Atlantic Cement Co., Inc.
Wet process; 10,000,000 bbl.
NORTH CAROLINA
Glens Falls
Glens Falls Portland Cement Co.
Wet process; 1,850,000 bbl.
Castle Hayne
Ideal Cement Co.
Wet process; 3,500,000 bbl.
Howes Cave
Penn-Dixie Cement Corp.
Dry process; 1,650,000 bbl.
Hudson
Lone Star Cement Corp.
Wet process; 3,000,000 bbl.
Universal Atlas Cement Div.
U. S. Steel Corp.
Dry process; 4,300,000 bbl.
Jamesville
Alpha Portland Cement Co.
Wet process; 900,000 bbl.
OHIO
Barberton
Pittsburgh Plate Glass Co.
Chemical Division
Wet process; 1,500,000 bbl.
Fair born
Southwestern Portland Cement Co.
Wet process; 3,300,000 bbl.
Universal Atlas Cement Div.
U. S. Steel Corp.
Wet process; 2,500,000 bbl.
tronton
Alpha Portland Cement Co.
Dry process; 1,200,000 bbl.
MANUFACTURE OF PORTLAND CEMENT
41
-------
Middle Branch Tulsa
Diamond Portland Cement Co. Dewey Portland Cement Co.
Div. Flintkote Company Div. American-Marietta Corp.
Dry process; 3,000,000 bbl. Dry process; 2,800,000 bbl.
Paulding
OREGON
General Portland Cement Co.
Wet process; 2,500,000 bbl.
Gold Hill
Silica
Ideal Cement Co.
Medusa Portland Cement Co. Wet process; 700,000 bbl.
Dry process; 1,450,000 bbl.
Lime
Superior
Oregon Portland Cement Co.
Marquette Cement Manufacturing Wet process; 1,200,000 bbl.
Co.
Dry process; 1,250,000 bbl.
Lake Oswego
Zanesville Oregon Portland Cement Co.
Wet process; 2,000,000 bbl.
Columbia Cement Mfg. Co.
Sub. Pittsburgh Plate Glass Co.
Wet process; 3,000,000 bbl.
PENNSYLVANIA
OKLAHOMA Bath
Keystone Portland Cement Co.
Ada Wet process; 3,300,000 bbl.
Ideal Cement Co.
Wet process; 4,150,000 bbl. Bessemer
Bessemer Limestone
Pryor and Cement Co.
Wet process; 3,000,000 bbl.
Oklahoma Cement Co.
Dry process; 2,000,000 bbl.
42 ATMOSPHERIC EMISSIONS FROM THE
-------
Bethlehem
Neville Island
National Portland Cement Co.
Wet process; 2,000,000 bbl.
Marquette Cement Mfg. Co.
Wet process; 1,750,000 bbl.
Cementon
Whitehall Cement Mfg. Co.
Dry process; 3,000,000 bbl.
Northampton
Dragon Cement Co.
Div. American-Marietta Corp.
Dry process; 2,000,000 bbl.
Coplay
Universal Atlas Cement Div.
Coplay Cement Manufacturing Co. U. S. Steel Corp.
Dry process; 2,250,000 bbl. Wet process; 2,900,000 bbl.
Egypt
Giant Portland Cement Co.
Dry process; 1,850,000 bbl.
Evansville
Allentown Portland Cement Co.
Dry process; 2,572,000 bbl.
(5,000,000 bbl. in 1966)
Fogelsville
Lehigh Portland Cement Co.
Dry process; 2,210,000 bbl.
Nazareth
Lone Star Cement Corp.
Dry process; 3,600,000 bbl.
Nazareth Cement Co.
Dry process; 2,400,000 bbl.
Perm-Dixie Cement Corp.
Dry process; 1,836,000 bbl.
Stockertown
Hercules Cement Co.
Div. American Cement Corp.
Dry process; 3,500,000 bbl.
Universal
Universal Atlas Cement Div.
U. S. Steel Corp.
Dry process; 2,600,000 bbl.
Wampum
Medusa Portland Cement Co.
Dry process; 2,500,000 bbl.
West Conshohocken
Allentown Portland Cement Co.
Wet process; 2,100,000 bbl.
MANUFACTURE OF PORTLAND CEMENT
43
-------
West Winfield
Penn-Dixie Cement Corp.
Wet process; 1,908,000 bbl.
King sport
Penn-Dixie Cement Corp.
Wet process; 1,620,000 bbl.
SOUTH CAROLINA
Harleyville
Giant Portland Cement Co.
Carolina Giant Division
Wet process; 4,000,000 bbl.
Holly Hill
Santee Portland Cement Corp.
Wet process; 2,000,000 bbl.
(To be completed in 1966)
SOUTH DAKOTA
Rapid City
South Dakota Cement Plant
Wet process; 3,300,000 bbl.
TENNESSEE
Cowan
Marquette Cement Mfg. Co.
Wet process; 1,020,000 bbl.
Knoxville
Volenteer Portland Cement Co.
Div. of Ideal Cement Co.
Wet process; 2,800,000 bbl.
Nashville
Marquette Cement Mfg. Co.
Wet process; 1,200,000 bbl.
North Chattanooga
General Portland Cement Co.
Signal Mountain Div.
Wet process; 1,750,000 bbl.
Richard City
Penn-Dixie Cement Corp.
Wet process; 1,584,000 bbl.
TEXAS
Amarillo
Southwestern Portland Cement Co.
Wet process; 1,200,000 bbl.
Cementville
San Antonio Portland Cement Co.
Wet process; 2,500,000 bbl.
44
ATMOSPHERIC EMISSIONS FROM THE
-------
Corpus Christ!
Halliburton Portland Cement Co.
Wet process; 1,400,000 bbl.
Eagle Ford (P. Q. Dallas)
General Portland Cement Co.
Wet process; 3,650,000 bbl.
Gulf Coast Portland Cement Co.
Wet process; 1,500,000 bbl.
Maryneal
Lone Star Cement Corp.
Dry process; 2,900,000 bbl.
Midlothian
Dallas
Lone Star Cement Corp
Wet process; 4,000,000 bbl.
El Paso
Southwestern Portland Cement Co.
Dry process; 1,800,000 bbl.
Forth Worth
General Portland Cement Co.
Trinity Division
Wet process; 4,000,000 bbl.
Gelena Park
Ideal Cement Co.
Wet process; 4,075,000 bbl.
Houston
General Portland Cement Co.
Trinity Division
Wet process; 3,650,000 bbl.
Lone Star Cement Corp.
Wet process; 3,300,000 bbl.
Texas Industries, Inc.
Wet process; 1,400,000 bbl.
Gifford-Hill and Co., Inc.
Wet Process; 1,500,000 bbl.
(To be completed in 1966)
Odessa
Southwestern Portland Cement Co.
Dry process; 1,200,000 bbl.
Orange
Texas Portland Cement Co.
Wet process; 2,000,000 bbl.
San Antonio
Longhorn Portland Cement Co.
Wet process; 2,700,000 bbl.
Capitol Aggregates, Inc.
Wet process; 1,000,000 bbl.
MANUFACTURE OF PORTLAND CEMENT
45
-------
Waco
University Atlas Cement Div.
U. S. Steel Corp.
Dry process; 2,000,000 bbl.
UTAH
Devil's Slide
Ideal Cement Co.
Wet process; 2,000,000 bbl.
Salt Lake City
Portland Cement Co. of Utah
Wet process; 1,000,000 bbl.
VIRGINIA
Fordwick
Lehigh Portland Cement Co.
Dry process; 1,690,000 bbl.
Lone Star
Lone Star Cement Corp.
Dry process; 3,500,000 bbl.
Norfolk
Lone Star Cement Corp.
Wet process; 2,300,000 bbl.
WASHINGTON
Bellingham
Permanente Cement Co.
Olympic Plant
Wet process; 1,900,000 bbl.
Concrete
Lone Star Cement Corp.
Wet process; 1,700,000 bbl.
Grotto
Ideal Cement Co.
Wet process; 675,000 bbl.
Metaline Falls
Lehigh Portland Cement Co.
Dry process; 1,290,000 bbl.
Seattle
Lone Star Cement Corp.
Wet process; 1,300,000 bbl.
Spokane
Ideal Cement Co.
Dry process; 700,000 bbl.
46
ATMOSPHERIC EMISSIONS FROM THE
GPO 8O3—789—3
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WEST VIRGINIA
Martinsburg
Capital Cement Co.
Div. American-Marietta Corp.
Wet process; 4,200,000 bbl.
WISCONSIN
Manitowac
Manitowac Portland Cement Co.
Sub. Medusa Portland Cement Co.
Wet process; 2,000,000 bbl.
Milwaukee
Marquette Cement Mfg. Co.
Dry process; 1,250,000 bbl.
WYOMING
Laramie
Monolith Portland Midwest Co.
Wet process; 1,100,000 bbl.
MANUFACTURE OF PORTLAND CEMENT 47
GPO 603—789-2 * U. S. GOVERNMENT PRINTING OFFICE : 1 968 — 3C*-8l(5/<3
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