ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
PHELPS DODGE
AJO
NATIONAL ENFORCEMENT INVESTIGATIONS CENTER
DENVER, COLORADO
A 1
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STATE IMPLEMENTATION PLAN
INSPECTION OF
PHELPS DODGE CORPORATION
NEW CORNELIA BRANCH SMELTER
Ajo, Arizona
May 1976
ENVIRONMENTAL PROTECTION AGENCY
NATIONAL ENFORCEMENT INVESTIGATIONS CENTER
Denver
OFFICE OF AIR QUALITY PLANNING AND STANDARDS
Durham
REGION IX
San Francisco
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CONTENTS
INTRODUCTION ...... 1
PROCESS DESCRIPTION 2
EMISSION SOURCES AND RELATED
CONTROL EQUIPMENT 7
EMISSIONS DATA 11
BIBLIOGRAPHY 16
TABLES
1 Smelter Process Equipment and
Operating Data 4
2 Smelter Air Pollution Control
Equipment and Operating Data .... 9
3 Particulate Matter Emissions Test
Results 14
FIGURES
1 Phelps Dodge, Ajo Process Flow
Diagram 3
2 Phelps Dodge, Ajo Plant Layout,
Process Exhaust Flow and Air
Pollution Control Systems 8
APPENDICES
A NEIC Information Request
Letter to Phelps Dodge .... 18
B Phelps Dodge Response to
NEIC Information Request .... 29
C SIP Regulation Applicable to
Phelps Dodge 51
D Example Calculations of Gas
Flow Rates 53
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PHELPS DODGE
AJO, ARIZONA
SUMMARY AND CONCLUSIONS
Phelps Dodge Corporation operates a mine, concentrator, and smelter
in Ajo, Arizona. An inspection to acquire data with which to evaluate
the design and operation of existing particulate matter air pollution
control equipment at the smelter and to survey the suitability of the
smelter to be emission tested was conducted by Federal and State personnel
on January 15, 1976. Substantial amounts of process, control equipment,
and stack sampling information were requested of, and received from,
Phelps Dodg'e.
The following conclusions are based on the inspection and a review
of the information obtained:
1. The two reverberatory furnace ESP's do not appear to have
sufficient capacity to handle the gas volumes coming to them.
Calculations from data provided show that the ESP's may be trying
to handle gas volumes perhaps 10% greater than they were designed
to handle - 2,200 m^/min (77,900 scfm) as compared to 2,000 m^/min
(70,400 scfm).
2. The DMA SO^ absorption plant was not in operation and had not
been for considerable time. Since this control system treats half
of the reverberatory furnace ESP exhaust gas volume, adequate
particulate matter and S0£ control depends on its operation. If
problems with the DMA plant's operation continue, consideration
should be given to using the gas cleaning system preceding the DMA
plant as an additional particulate matter control system.
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3. Phelps Dodge has concluded it must conduct specific process
operations in harmony with its air pollution control system. For
example, only one converter is operated at a time at the Ajo
smelter. Although the converter ESP's can handle larger gas
volumes, the acid plant and the preceding gas cleaning system
cannot.
4. Three source tests have been conducted at the Ajo smelter, two
by Engineers Testing Laboratories, Phoenix, and one by Stearns-
Roger, Denver. With the possible exception of the latter test,
procedural errors were made to invalidate the test results.
However, all three tests indicate that the smelter is not in
compliance with the applicable process weight regulation. None of
the source test reports contain an adequate description of methods
and procedures employed by the test teams.
5. Sufficient process data was not acquired by the source test
teams to compare process occurrences with source test results.
Because of the complexity of smelter process operations, specific
process data must be logged simultaneously with data acquired
during source testing. Conclusions such as data comparability,
equivalency, precision, and accuracy cannot" be made without both
data sets.
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INSPECTION OF
PHELPS DODGE CORPORATION
NEW CORNELIA BRANCH
Ajo, Arizona
January 15, 1976
602/387-7451
INTRODUCTION
The Phelps Dodge Corporation, New Cornelia Branch, operates a mine,
concentrator, and smelter at Ajo, Arizona, to produce anode copper from
a chalcopyrite (copper-iron sulfide) concentrate. Average anode copper
production during 1975 was 165 m. tons (185 tons)/day.
On December 16, 1975, the manager of the New Cornelia Branch was
requested by letter to provide process and air pollution control in-
formation on the New Cornelia operation and informed of a planned plant
inspection [Appendix A]. On January 15, 1976, the following EPA and
State personnel conducted a process inspection: Mr. Meade Stirland,
Arizona Department of Health; Mr. Lloyd Kostow, USEPA, Region IX; Mr.
Reid Iversen, USEPA, ESED; Mr. Gary D. Young, USEPA, NEIC; Mr. Jim V.
Rouse, USEPA, NEIC. The requested data were not available at the time
of the inspection, but were subsequently furnished by letter dated
February 2, 1976 [Appendix B].
The purpose of the inspection was to acquire data with which to
evaluate the design and operation of existing particulate matter air
pollution control equipment and to survey the suitability of the smelter
to be emission tested. The inspection focused primarily on the smelter,
although the mine and concentrator were both inspected. Also examined
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were the process equipment, the particulate matter emission sources, and
the air pollution control equipment. The inspection team surveyed the
existing smelter source testing facilities and locations for accessibility
and capability to be source tested.
Company personnel were cooperative throughout the inspection. All
the information requested was supplied during the inspection, the exit
interview, or by subsequent letter or telephone call. Company personnel
participating included: Mr. David H. Orr, Plant Manager; Mr. Forrest R.
Rickard, Smelter Superintendent; Mr. James E. Foard, Metallurgist,
Phelps Dodge Western Corporate Office.
The applicable regulation contained in the Arizona State Implemen-
tation Plan (SIP) of specific interest for this inspection was the
process weight regulation [Appendix C]. This regulation was promulgated
as 40 CFR §52.125 on May 14, 1973, to replace the State's process weight
regulation, which was determined by EPA to be not sufficiently stringent.
The regulation provides for an allowable emission rate for each process
unit based upon the production feed rate to the unit.
PROCESS DESCRIPTION
Figure 1 is a simplified process flow diagram for the smelter.
Table 1 is a list of the smelter process equipment and operating data.
Concentrate is delivered from the New Cornelia concentrator to the
smelter by a 61 cm (24 in) belt conveyor. Along the way, concentrate is
dried in a rotary drier, which is fired by either natural gas, when
available, or diesel fuel.
Upon entering the smelter building, the belt-delivered concentrate
is mixed with limestone flux in predetermined proportions and bedded.
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SLAG
CONCENTRATES
REVERBERATORY
FURNACE
PREC IP ITATES
LIM EROCK
MATTE
BLISTER
Cu f
LI6HT
ANODE
CONVERTERS (3)
Cu
FURNACE
B LISTER
Cu
SILICA FLUX
SLAQ
OXID IZING
FURNACE
CASTING WHEEL
REFORMED GAS
AIR
Figure 1. Phelps Dodge, A/o Process Flow Diagram
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4
Table 1
SMELTER PROCESS EQUIPMENT AND OPERATING DATA
PHELPS DODGE CORPORATION
Ajoj Arizona
Parameter
Reverberatory
Furnace
Converters
No. of Units
1
3
Feed Constituents^
C,P,R,
,L,CS
M,F,R
Feed Rate
C,P,R,L
(m. tons/day)(tons/day)
613 676
(m.tons/day)(tons/day)
725 799
CS
431
475
Total
1,044
1,151
Size of Unit
width
length
height
(meters)
9
30
3
(feet)
30
100
11
(meters) (feet)
diameter 4 13
length 9 30
Hours of Operation/month
Gas Volume Generated
624
Exit Gas Temperature
ft
(m /min)
2,200
(°C)
309*
(scfm)
77,900
(°F)
588*
522
n]
1,100
(°C)
340**
(scfm)
39,500
(°F)
650**
i Concentrates, Precipitates3 Reverts3 Limestone3 Matte, Converter
Slagj Flux (siliceous)
tt Recordings* or estimate** following waste heat boilers
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As available, dusts from dust collection facilities are also added to
the concentrate and crushed limestone. Concentrates from other copper
concentrators -- notably Tyrone, Baghdad, and Bruce, together with
copper precipitates from the Phelps Dodge Tyrone operation -- are also
bedded as available.
The various materials to be smelted are put into 9 m. tons (10
tons) "cans," which are large cylindrical containers used in charging
the reverberatory furnace. The filled can is moved by an overhead crane
either to storage or to one of six furnace charging stations for the
single reverberatory furnace.
The reverberatory furnace is 30 m (100 ft) long and 9 m (30 ft)
wide, inside dimensions, mounted on a heavily reinforced concrete
fouhdation. The reverberatory furnace is fired with natural gas, or
with fuel oil if natural gas delivery is interrupted.
The reverberatory furnace walls are made of silica brick, with an
interior protective surface of basic brick and, in the area of the
crucible, a mixture of tamped periclase and firebrick. The walls also
include 51 cm (20 in) high copper water jackets immediately above the
crucible. The reverberatory furnace roof is a sprung arch constructed
of silica brick. The furnace walls and arch are maintained by hot
patching with silica slurry.
The reverberatory furnace is charged by positioning a can of
concentrate at one of the six charging stations. A door covering the
charge port is opened and a short feeder conveyor, located under the
charge hopper, is started. The bottom gates of the can are then opened
and the charge falls into a small feed hopper of the charging machine
immediately below the can. The charging machine, referred to as a
"slinger," is a short, high-speed, portable belt conveyor pivoted on a
vertical shaft to permit lateral swinging. The concentrate falls from
the feed hopper onto the rapidly moving belt; as the concentrate moves
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over the belt head pulley, it is discharged into the furnace. The usual
charge is 1.8 to 3.6 m. tons (2 to 4 tons) at an average rate of approxi-
mately 0.9 m. ton (1 ton)/min.
The normal molten material depth in the reverberatory furnace is
approximately 120 cm (46 in), of which 66 to 76 cm (26 to 30 in) is
matte. Slag is tapped through the side wall and flows through a launder
into slag pots which are hauled by rail to the slag dump. Matte is
tapped as required by the converter or reverberatory furnace conditions
into ladles resting on electric-powered trucks which can be moved into
the converter aisle.
The matte ladles are picked up by overhead crane and are charged to
one of three Pierce-Smith 4 x 9 m (13 x 30 ft) converters. An initial
charge to a converter normally consists of four 14 m. ton (16 ton)
ladles of matte. Air through tuyeres is blown into the charge, flux is
added to the charge, and slag produced is skimmed into a ladle. The
converter slag is then returned to the reverberatory furnace by the
overhead crane. Additional matte is added to the converter to produce a
total of approximately 50 m. tons (55 tons) of light blister copper.
The light blister copper is poured into ladles and carried by
overhead crane to the 4 m (12 ft) diameter Great Falls converter which
has been modified to serve as an oxidizing furnace. The charge in the
oxidizing furnace is blown with air through tuyeres to complete the
sulfur removal. This use of the holding furnace for the final oxidation
is considered necessary to prolong brick life in the converters and
anode furnace.
Following completion of oxidation in the Great Falls converter, the
copper is transferred to the anode furnace, which is 9 m (30 ft) long
and 4 m (13 ft) in diameter. Reformed natural gas (cracked methane) is
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introduced through tuyeres for final copper reduction. The anode-grade
molten copper is cast into 330 kg (720 lb) anodes on a 22-mold casting
wheel. Anodes are cooled, inspected, and loaded on railroad flat cars
for shipment to the Phelps Dodge refinery in El Paso, Texas.
EMISSION SOURCES AND RELATED CONTROL EQUIPMENT
The primary particulate matter sources at the Ajo smelter are the
reverberatory furnace and the converters. The majority of the exhaust
gas volumes produced by these sources is treated by control systems
which are discussed below. However, fugitive emissions from feeding
concentrates, skimming converter slag, or returning converter slag are
neither collected, nor treated, but are exhausted directly to the
atmosphere. The reverberatory furnace matte and slag tap areas are
hooded, and collected gases containing particulate matter are exhausted
untreated directly to the smelter main stack. Similarly, converter
"smoke" not collected by the primary hood system, is collected by a
secondary hood system and exhausted untreated directly to the smelter
main stack. The oxidizing and anode furnaces also emit some untreated
particulate matter directly to the atmosphere above the converter aisle;
the former probably emits the greater amount, however, the concentrations
are indeterminate.
Figure 2 is a diagram of the Ajo plant layout, the air pollution
control systems, and the exhaust gas flow. Table 2 summarizes certain
design and operating data for the individual air pollution control
systems. Appendix A contains more specific information on each control
system.
Reverberatory Furnace Control System
The principal reverberatory furnace exhaust gases pass through a
pair of waste heat boilers which partially cool the gases and then enter
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MAIN STACK
REVERBERATORY
FURNACE
ESP
EXHAUS
WASTE
HEAT
BOILERS
ANODE
CONVERTERS
O)
FURNACE
OXIDIZING
FURNACE
CASTING 'WHEEL
WASTE HEAT BOILERS
CATALYST CHAMBER
MIST ESP
ESP
(2)
DRYING TOWER
\
HUMIDIFYING
.TOWERS ^ -
MIST, ESP
IEAT EXCHANGERS
ABSORBING TOWER
COOLING TOWERS
I
r ~
I
EXHAUST,
DMA STRIPPING TOWER
DMA ABSORBING TOWER
Figure 2. Phelps Dodge, A/o Plant Layout, Process Exhaust Flow,
and Air Pollution Control Systems
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Table 2
SKELTER AIR POLLUTION CONTROL EQUIPMENT AND OPERATING DATA
PHELPS DODGE CORPORATION
Ajo, Arizona
Control Manufacturer
Device
Date of
Installation/ No. of
Modification Units
Gas Flow Operating Pressure Drop Collection Velocity Retention
Rate Temperature Area Time
m3/min scfm °C °F cm H2° fn
2 2
m ft m/sec ft/sec
sec
ESP Western
Precipitator
(Type R)
Scrubbers
a b
Reverberatory Furnace
8/73 2 2,200 77,900 309 588 1.3
(with 2 inlet
sta9«) 230 4 SO
outlet
1/75 1 700- 25,000- 200- 400- 3.8
1,200 43,000 290 550
inlet
0.5 1,927 20,738 0.9 3.0
1.5
NA
NA
6.6
NA
52-66 125-150
outlet
Liquid
S02 plant
ESP
Western
Precipitator
(Type R)
7/74
1.100 38,500 32
90
Unknown
NA
NA
NA
Converter
2 g
1972 (with 3 1,100 39,500 340 650 1.3 0.5 2,890 31,104 1.3 4.2
stages) inlet
7.1
Scrubbers
t b
1/75
230 450
outlet
700- 25,000- 200- 400- 3.8
1,200 43,000 290 550
inlet
1.5
NA
NA
NA
Acid Plant 9
7/74
52-66 125-150
outlet
990- 35,000- 39 102 Unknown
1,200 42,000 inlet
NA
NA
NA
a Only includes humidifying touer, not the cooling tower, preceding DMA plant
b Design and construction by Stearna-Rogcr in collaboration with Monsanto; no special type or model number designated
c SA " Hot applicable
d DMA process developed by ASARCO; engineering and construction by .Steprns-Roner , \
e With one converter in operation (dfouJo QBMtytr tO -rfT 0**")
I Only includes humidifying touer, not the cooling touer, preceding the acid plant
g Design by Monsanto; no model number
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a common plenum chamber for the two independent, parallel, electrostatic
precipitators (ESP's). The two ESP's were designed to handle 4,200
m3/min (150,000 acfm) at 315°C (600°F) and 1.0 kg/cm2 (13.8 psia) [1,990
m /min (70,400 scfm)]. [See Appendix D for example calculations of gas
flow rates.] However, the typical gas flow is 4,640 m /min (164,000
acfm) at about 309 °C (588°F) [2,200 (77,900 scfm)]. Each ESP
2
consists of two stages with a total collection area of 1,930 m (20,700
2
ft ). Gas treatment retention time is less than 7 seconds with an
average gas velocity of 0.9 m (3 ft)/sec. The pressure drop across the
unit is 1.3 cm (0.5 in) of water maximum.
About 50% [1,100 m3/min (38,500 scfm)] of the gas stream can be
directed through gas cleaning equipment prior to the DMA (dimethyl -
aniline) S0£ absorption plant. The other part of the gas stream is
exhausted to and discharged from the 110 m (360 ft) smelter main stack.
The gas stream directed to the DMA plant first enters a humidifying
tower where the gases are evaporatively cooled by a weak acid solution
and some of the remaining particulate matter is removed. The gases then
enter a cooling tower in which a weak acid solution percolating down
through packing cools the ascending gases and removes more of the re-
maining particulate matter. The gases then enter the mist precipitator
in which any acid mist or remaining dust particles are removed. The
clean gas stream then enters the DMA absorption tower in which S0£ is
removed. Any acid mist formed is removed in the acid scrubbing section
of the DMA absorption tower before the gas stream is discharged to the
atmosphere through a 15 m (50 ft) stack atop the tower.
Converter Control System
The principal converter particulate matter-laden exhaust gases are
produced when air is blown into the converter through the tuyeres to
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oxidize the iron and copper sulfides. Approximately 100% additional air
infiltrates around the primary hoods. This additional air becomes a
part of the converter exhaust gas stream ducted to a waste heat boiler
which further cools the gas stream. The gases then enter a common
balloon flue and are carried to two independent, parallel ESP's. The
two ESP's were designed to handle a total of 5,900 m^/min (210,000 acfm)
at 340°C (650°F) and 1.0 kg/cm^" (13.8 psia) [2,660 m^/min (94,100
scfm)]. Phelps Dodge normally only operates one converter which, with
infiltration air, produces a total gas volume of 1,120 m /min (39,500
scfm). Each ESP consists of three stages with a total collection area
2 2
of 2,890 m (31,100 ft J. Gas treatment retention time is about 7
seconds with an average gas velocity of just over 1.2 m/sec (4 ft/sec).
The pressure drop across the unit is 1.3 cm (0.5 in} of water maximum.
The gas stream is then directed through gas cleaning equipment
prior to the single-contact acid plant. Following the ESP's, the gas
stream enters a humidifying tower, a cooling tower, and a pair of mist
precipitators which are designed and function identically to the gas
cleaning system preceding the DMA SO2 absorption plant. The clean gas
stream then enters the acid plant where it is dried, the SO2 converted
into S0g, and the S0^ absorbed in acid to form stronger acid. Between
180 and 380 m. ton (200 to 425 tons) of 92 to 97% strength acid is
produced daily. The exit gas from the absorption tower passes through a
mist eliminator before it enters a duct which carries the exhaust gases
to the smelter main stack.
EMISSIONS DATA
Three separate source tests were conducted at the Phelps Dodge, Ajo
smelter during 1975. The first two were performed by the Engineers
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Testing Laboratories (ETL), Phoenix, in April and September; the third
was performed by Stearns-Roger (S-R), Denver, in November. All of the
tests were conducted at the 39 m (127 ft) elevation of the smelter main
stack where the stack diameter is 6.4 m (20 ft 10 in). Each test was
attempted as a compliance test following the prescribed methods (Methods
1-5) in the regulation [Appendix C]. The stack has four sampling parts,
however, only two are at 90° angles. During the source tests ETL used
the two at 90° angles, while S-R used three ports. The sampling ports
are located approximately four stack diameters downstream from the point
at which the exhausts enter the smelter main stack, requiring a minimum
of 36 traverse points.
Individual hourly process weights were determined by dividing the
daily tonnage fed to each process unit by 24. The allowable emissions
were calculated as the sum of the allowable emissions for the reverbera-
tory furnace and converters, taken as separate processes as prescribed
by the applicable process weight regulation. The sampling results were
then compared with the allowable emissions; in every case the measured
emission exceeded the allowable emission.
Following is a summary of each test, containing comments regarding
the methods, procedures, and results of each test.
ETL: April 22-24, 1975
Sample points were calculated for 12 points on each of the two
diameters, instead of for 18 points as Method 1 prescribes for a sampling
station four duct diameters downstream from a flow disturbance. In
addition, a 2.4 m (8 ft) probe was used because of the apparent limitation:
of the support monorail. Therefore, only the first 5 traverse points
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13
could be sampled on each diameter. In fact, only traverse points #1 and
#2 were used in the first run and only traverse points #3, #4, and §5 in
the second and third run. The sampling train used was a Method 5
configuration with 10% hydrogen peroxide in the impingers. Stack
moisture was obtained by impinger weight gain corrected for sulfur
compounds. The DMA absorption plant was not in operation during
this test. The results of the three runs are presented in Table 3.
ETL: September 17-19, 1975
Sample points were calculated for 32 points for each diameter.
However, during each of the three runs only traverse points #4 through
#16 were used on each of the two diameters. Traverse points #1 through
#3 could not be reached because the monorail support was too short for
the probe length they were using. The sampling train and the method of
moisture determination were the same as those used in the April test.
All the particulate matter control equipment was in operation during
each of the runs. The third run was abruptly terminated when the
reverberatory furnace arch collapsed, but not before a sample volume had
been collected which meets the minimum requirements for the test procedure.
Isokinetic variation was within prescribed Method 5 tolerances. The
results of the three runs are presented in Table 3.
S-R: November 10-13, 1975
Three of the four sampling ports were used for this test — the two
at 90° and the third which is about 135° from the other two. Twelve
traverse points were calculated and used on each of the three radii. A
Method 5 sampling train was used with 80% isopropanol in the first and
second impingers, nothing in the third impinger, and 5% hydrogen peroxide
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Table 3
PARTICULATE MATTER EMISSIONS TEST RESULTS
PHELPS DODGE CORPORATION
Ajoj Arizona
Test Date Stack Gas Moisture Actual Allowable
Run Temperature Volume Content Emissions Emi ssions
°F °C acfm m^/min % lb/hr kg/hr lb/hr kg/hr
ETL
1
4-22-75
254
123
390,000
11,000
4.0
214
97
61
28
2
4-23-75
252
122
443,000
12,500
4.1
173
78
61
28
3
4-24-75
255
124
473,000
13,400
4.0
207
94
59
27
12
9-17-75
213
101
337,000
9,540
3.5
280
127
63
29
13
9-18-75
212
100
309,000
8,750
3.2
151
68
61
28
14
9-19-75
212
100
348,000
9,850
2.6
164
74
61
28
S-R
1
11-10-75
205
96
311,800
8,830
2.3
295
134
ND+
2
11-12-75
215
102
350,200
9,920
2.5
647
293
ND
3
11-13-75
212
100
335,800
9,510
3.5
409
186
ND
7
t Not Determined
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15
in the fourth impinger. Moisture content was acquired simultaneously
with each particulate run by a separate train run according to Method 4
in the fourth sampling port. Stack gas pressure and Orsat samples were,
obtained at the same sampling port. The results of the three runs are
presented in Table 3.
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BIBLIOGRAPHY
1. Letter from D. H. Orr, Manager, New Cornelia Branch, Phelps Dodge
Corporation to Thomas P. Gallagher, Director, EPA-NEIC, Denver, Feb.
2, 1976.
2. Operations at New Cornelia Copper Smelter of Phelps Dodge Corporation.
James W. Byrkit, 1952; Forrest R. Rickard, 1965.
3. Gas Treatment Facilities at the New Cornelia Branch of Phelps Dodge
Corporation, Ajo, Arizona. Forrest R. Rickard, Smelter Superin-
tendent, Apr. 26, 1974.
4. SOp Absorption Plant at the New Cornelia Branch of Phelps Dodge
Corporation, Ajo, Arizona. W. J. Chen, Gas Treatment Plant Foreman,
Apr. 26, 1974.
5. Engineering Drawing AS-09-1-02, Revision 4. Gas Systems Modifications,
General Plot Plan. Stearns-Roger Corporation, Denver, Jan. 2,
1975.
6. Compilation and Analysis of Design and Operating Parameters of the
Phelps Dodge Corporation New Cornelia Branch Smelter, Ajo, Arizona
for Emission Control Studies. Pacific Environmental Services,
Inc., Santa Monica Jan. 1976.
7. Particulate Emissions Analysis, Reverberatory Furnace and Converters,
22 through 24 April 1975." Engineers Testing Laboratories, Inc.,
Phoenix, May 2, 1975.
8. Particulate Emissions Analysis, Reverberatory Furnace and Converters,
Ajo Smelter, September 17, 18, and 19, 1975. Engineers Testing
Laboratories, Inc., Phoenix, Sept. 25, 1975.
9. Ajo Copper Smelter Tests for Particulate Emission, Phelps Dodge
Corporation, New Cornelia Branch, November 10-13, 1975. Stearns-
Roger Incorporated, Denver, Dec. 1, 1975.
10. Letter from James E. Foard, Metallurgist for Western Operations,
Phelps Dodge Corporation to Gary D. Young, EPA-NEIC, Denver, Apr.
6, 1976.
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APPENDICES
A NEIC Information Request
Letter to Phelps Dodge
B Phelps Dodge Response to
NEIC Information Request
C SIP Regulation Applicable to
Phelps Dodge
D Example Calculations of Gas
Flow Rates
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Appendix A
NEIC Information Request
Letter to Phelps Dodge
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ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
NATIONAL FIELD INVESTIGATIONS CENTER-DENVER
BUILDING 53, BOX 25227. DENVER FEDERAL CENTER
DENVER, COLORADO 80225
December 17, 1975
D. H. Orr
Manager
New Cornelia Branch
PJielps-Dodge Corporation
Ajo, Arizona 85231
Dear Mr. Orr:
The Environmental Protection Agency has undertaken a program to
evaluate the performance characteristics of particulate control facilities
at the copper smelters in Arizona and Nevada. Representatives of EPA
will observe each smelter's process operations and air pollution control
facilities, review source test data, examine appropriate records, etc.,
during a site inspection of each smelter.
In anticipation of such a site inspection of your smelter, we have
prepared the attached list of detailed information needs which we intend
to use as a discussion outline during our inspection. We would appreciate
it if you could inform the appropriate company personnel about the
attached list and the forthcoming inspection of your facility so that
the necessary information will be readily available and the inspections
can be expedited.
We are conducting these inspections under the authority of Section
114(a)(ii) of the Clean Air Act, which authorizes representatives of EPA
to enter facilities for the purpose of determining whether the facility
is in violation of any requirement of a state implementation plan. At
your facility, we anticipate that EPA or a contractor hired by EPA will
be conducting an emissions source test for particulate matter within the
next few months. Therefore, EPA will make a source test pre-survey,
either separately or in conjunction with our site inspections, prior to
performing such a source test.
If you have any questions concerning the purpose of these site
inspections, please feel free to contact Mr. Gary D. Young of my staff
(303/234-4658) or Mr. Larry Bowerman, EPA Region IX (415/556-6150). Mr.
Young will be in contact with you within the next few weeks concerning a
site inspecton of your smelter during January or early February.
Sincerely,
Thomas P. Gallagher
Director
Attachment
cc: Richard O'Connell
Bruce Scott
-------
20
COPPER SMELTER INFORMATION NEEDS
A. GENERAL
1. Plant location
2. Person to contact regarding plant survey information needs, his
telephone number and address
3. Simple block flow diagram showing smelter process equipment, air
pollution control devices, and stack configuration
B. PROCESS
1. General
a. Detailed description of the process, including flow diagrams,
unique features, and how the process operates
b. Definition of normal operation
c. Actual production rate (lbs blister copper/hr and percent Cu)
d. Type and quantity of fuel consumed
Oil
- i.
Heating value (BTU's/gal)
ii.
Percent sulfur (by weight)
iii.
Percent ash (by weight)
iv.
Specific gravity
v.
Consumption (gals or bbls/yr)
Gas
- i.
Type of gas (constituents in percent by weight)
ii.
Density (lbs/SCF)
iii.
Heating value (BTU's/SCF)
iv.
Percent sulfur (by volume and grains/SCF)
v.
Consumption (SCF/yr)
Coal
- i.
Heating value (BTU's/T)
ii.
Percent sulfur (by weight)
iii.
Percent ash (by weight)
iv.
Consumption (lbs/unit/hr)
e. Ore composition, including a typical percent and range of
percentages for each chemical constituent
f. Flux composition, including a typical percent and range of
percentages for each chemical constituent
g. Standard conditions - pressure (psi) and temperature (°F). -
used to calculate SCFM
-------
21
2. Concentrators
a. Design process feed rate (lbs raw ore/hr)
b. Actual process feed rate (lbs raw ore/hr), including method
and estimated accuracy of measurement
c. Average number of hours of operation per month
d. Process instrumentation used, including data for a typical
reading and range of readings
e. Description of where and how samples of process material can
be collected
f. Description of typical types of process fluctuations and/or
malfunctions, including frequency of occurrence and anticipated
emission results
g. Expected life of process equipment (years)
h. Plans to modify or expand process production rate
3. Roasters
a. Design process feed rate (lbs concentrate/hr)
b. Actual process feed rate (lbs concentrate/hr), including
method and estimated accuracy of measurement
c. Design process gas volumes (SCFM)
d. Actual process gas volumes (SCFM), including method of
determination, calculation, or measurement
e. Actual process temperature (°F)
f. Average number of hours of operation per month
g. Process instrumentation used, including data for a typical
reading and range of readings
h. Description of where and how samples of process material
can be collected
i. Description of typical types of process fluctuations and/or
malfunctions, including frequency of occurrence and anticipated
emission results
-------
22
j. Expected life of process equipment (years)
k. Plans to modify or expand process production rate
Reverberatory furnaces
a. Design process feed rate (lbs calcine/hr + lbs flux/hr +
lbs converter slag/hr)
b. Actual process feed rate (lbs calcine/hr + lbs flux/hr +
lbs converter slag/hr), including method and estimated
accuracy of measurement
c. Design process gas volumes (SCFM)
d. Actual process gas volumes (SCFM), including method of
determination, calculation, or measurement
e. Actual process temperature (°F)
f. Average number of hours of operation per month
g. Process instrumentation used, including data for a typical
reading and range of readings
h. Description of where and how samples of process material can
be collected
i. Description of typical types of process fluctuations and/or
malfunctions, including frequency of occurrence and anticipated
emission results
j. Expected life of process equipment (years)
k. Plans to modify or expand process production rate
Converters
a. Design process feed rate (lbs matte/hr + lbs slag/hr +
lbs flux/hr)
b. Actual process feed rate (lbs matte/hr 4- lbs slag/hr +
lbs flux/hr), including method and estimated accuracy of
measurement
c. Design process gas volumes (SCFM)
d. Actual process gas volumes (SCFM), including method of
determination, calculation, or measurement
e. Actual process temperature (°F)
-------
23
f. Average number of hours of operation per month
g. Process instrumentation used, including data for a typical
reading and range of readings
h. Description of where and how samples of process material can
be collected
i. Description of typical types of process fluctuations and/or
malfunctions, including frequency of occurrence and anticipated
emission results
j. Expected life of process equipment (years)
k. Plans to modify or expand process production rate
6. Refining Furnaces
a. Design process feed rate (lbs blister copper/hr)
b. Actual process feed rate (lbs blister copper/hr), including
method and estimated accuracy of measurement
c. Design process gas volumes (SCFM)
d. Actual process gas volumes (SCFM), including method of
determination, calculation, or measurement
e. Actual process temperature (°F)
f. Average number of hours of operation per month
g. Process instrumentation used, including data for a typical
reading and range of readings
h. Description of where and how samples of process material can
be collected
i. Description of typical types of process fluctuations and/or
malfunctions, including frequency of occurrence and anticipated
emission results
j. Expected life of process equipment (years)
k. Plans to modify or expand process production rate
-------
24
C. EMISSIONS
1. List of sources of particulate emissions in the plant (including
fugitive emissions)
2. Level of uncontrolled particulate emissions by source (lbs/hr or
T/yr)
3. Existing source test data employed for particulates by stack,
process unit, or control device, including:
a. Test method
b. Data acquired
c. Operating process weight rate
d. Calculations
e. Test results
A. Particle size and chemical composition of uncontrolled particulate
emissions, including method of determination
5. Level of uncontrolled visible emissions by source (percent opacity)
and method of determination
6. Extent of and reason for variance of particulate emissions with:
a. Process design parameters
b. Process operating parameters
c. Raw material composition or type
d. Product specifications or composition
e. Production rate
f. Season or climate
g. Sulfur dioxide control
D. CONTROL SYSTEMS
1. Detailed description of the particulate and sulfur dioxide emissions
control systems, including:
a. Process treated
-------
25
b. Type of fuel consumed per unit
c. Quantity of fuel consumed per unit
d. Method of determination of design parameters
e. Engineering drawings or block flow diagrams
f. Expected life of control system
g. Plans to upgrade existing system
Electrostatic precipitators
a. Manufacturer, type, model number
b. Manufacturer's guarantees, if any
c. Date of installation or last modification and a detailed
description of the nature and extent of the modification
d. Description of cleaning and maintenance practices, including
frequency and method
e. Design and actual values for the following variables:
i.
Current (amperes)
ii.
Voltage
iii.
Rapping frequency (times/hr)
iv.
Number of banks
v.
Number of stages
vi.
Particulate resistivity (ohm-centimeters)
vii.
Quantity of ammonia injected (lbs/hr)
viii.
Water injection flow fate (gals/min)
ix.
Gas flow rate (SCFM)
X.
Operating temperature (°F)
xi.
Inlet particulate concentration (lbs/hr or grains/SCFM)
xii.
Outlet particulate concentration (lbs/hr or grains/SCFM)
xiii.
Pressure drop (inches of water)
Fabric filters
a. Manufacturer, type, model number
b. Manufacturer's guarantees, if any
c. Date of installation or last modification and a detailed
description of the nature and extent of the modification
-------
26
d. Description of cleaning and maintenance practices, including
frequency and method
e. Filter material
f. Filter weave
g. Bag replacement frequency
h. Forced or induced draft
i. Design and actual values for the following variables:
i. Bag area (ft^)
ii. Bag spacing (inches)
iii. Number of bags
iv. Gas flow rate (SCFM)
v. Operating temperature (°F)
vi. Inlet particulate concentration (lbs/hr or grains/SCF)j
vii. Outlet particulate concentration (lbs/hr or grains/SCF)
viii. Pressure drop (inches of water)
Scrubbers
a. Manufacturer, type, model number
b. Manufacturer's guarantees, if any
c. Date of installation of last modification and a detailed
description of the nature and extent of the modification
d. Description of cleaning and maintenance practices, including
frequency and method
e. Scrubbing media
f. Design and actual values for the following variables:
i. Scrubbing media flow rate (gals/min)
ii. Pressure of scrubbing media (psi)
iii. Gas flow rate (SCFM)
iv. Operating temperature (°F)
v. Inlet particulate concentration (lbs/hr or grains/SCF)
vi. Outlet particulate concentration (lbs/hr or grains/SCF)
vii. Pressure drop (inches of water)
Sulfuric acid plants
a. Manufacturer, type, model number
-------
27
b. Manufacturer's guarantees, if any
c. Date of installation or last modification and a detailed
description of the nature and extent of the modification
d. Description of cleaning and maintenance practices, including
frequency and method
e. Frequency of catalyst screening
f. Type of demister
g. Design and actual values for the following variables:
i. Production (T of acid/day)
ii. Conversion rate (percent)
iii. Acid strength (percent H2SO4)
iv. Number of catalyst beds
v. Gas flow rate (SCFM)
vi. Operating temperature (°'F)
vii. Inlet SO2 concentration (ppm)
viii. Outlet SO2 concentration (ppm)
ix. Acid mist (lbs H2SO4/T of acid)
x. Blower pressure (psi)
6. Liquid SO2 plants
a. Manufacturer, type, model number
b. Manufacturer's guarantees, if any
c. Date of installation or last modification and a detailed
description of the nature and extent of the modification
d. Description of cleaning and maintenance practices, including
frequency and method
e. Absorbing media
f. Design and actual values for the following variables
i. Production (T of S02/day)
ii. Conversion rate (percent)
iii. Gas flow rate (SCFM)
iv. Operating temperature (°F)
v. Inlet SO2 concentration (ppm)
vi. Outlet S0~ concentration (ppm)
vii. Acid mist (lbs H2SO4/T of SO2)
-------
28
7. Detailed description of how the particulate and sulfur dioxide
emission control systems operate
8. Description of instrumentation (flow meters, continuous monitors,
opacity meters, etc.) used, including manufacturer and model
number, data for typical and range of readings, and identification
of location by process unit, control system unit, or by stack
9. Description of typical types of control system malfunctions,
including frequency of occurrence and anticipated emission results
E. STACKS
1. Detailed description of stack configuration, including process
and/or control system units exhausted
2. Identification by stack of:
a. Heights (ft above terrain)
b. Elevation of discharge points (ft above sea level)
c. Inside diameters (ft)
d. Exit gas temperatures (°F)
e. Exit gas velocities (ft/sec)
-------
Appendix B
Phelps Dodge Response
To NEIC Information Request
-------
30
'Corporation New Cornelia Branch. Ajo, Arizona 85321
February 2, 1976
Mr. Thomas P. Gallagher, Director
Environmental Protection Agency
Office of Enforcement
National Field Investigations Center
Building 53, Box 25227,
Denver Federal Center
Denver, Colorado 80225
Dear Mr. Gallagher:
As promised at the time of the on-site inspection of the New Cor-
nelia Branch Smelter on January 15, attached is the response to the
questionnaire that accompanied your letter to me dated December 17, 1975.
The information requested in paragraph A(3) of the questionnaire
was given to your Mr. Gary D. Young during the Ajo visit and is not in-
cluded in this packet.
Very truly yours,
fJ. O_
D. H. Orr,
Manager
DHO:tjp
cc: W/0 A(3) information and test data
FRR
J MS
MPS
JHD
JFB
Nils I. Larson
¦?»
3 FEB1975
I K;\£:YED
^ NEIG
CEKVtR
-------
31
COPPER SMELTER INFORMATION NEEDS
Phelps Dodge Ajo Smelter
A. General
1. Phelps Dodge Corporation
New Cornelia Branch
Ajo, Arizona 85321
See Stearns-Roger Drawing No. AS 09-1-02
2. David H. Orr, Manager
P. O. Drawer 9
Ajo, Arizona 85321
(602) 387-7151
3. See following papers and drawings:
i) "Operations at New Cornelia Copper Smelter of Phelps
Dodge Corporation"
ii) Drawing AS 09-1-02
lii) "Gas Treatment Facilities at the New Cornelia Branch of
Phelps Dodge Corporation"
iv) "Use of the Gas Coolers (Waste Heat Boilers) in the
Converter Department at the New Cornelia Branch of
the Phelps Dodge Corporation".
v) "SO2 Absorption Plant at the New Cornelia Branch of
Phelps Dodge Corporation"
B. Process
1. General
a) See Item (3i 1 above.
b) Operations are normal whenever process units scheduled for
use achieve their nominal daily level of performance or availability.
-------
32
c) Copper Production
i) Anode Copper (99.75% Cu)
ii) Range : 125-210 tpd
iii) Average (1975) 185 tpd
6) Fuels
See Attachment 1 - Fuel Summary
Coal - None
g} See Attachment 2 - Composition of Materials Treated.
f} See Attachment 2 - Composition of Materials Treated.
g) Standard conditions*
14.7 psi (29.92 inches mercury)
70° F
* Except as noted.
2. Concentrators
(a) - (c)
Design
Actual
Feed Rate
(tpd)
32,000
32,300
Operation
(Hr./Mo.
NA
625
Weightometer
Accuracy (%)
+ 1.5
d) Weightometers are used to measure the ore into the plant. The
weightometers have limits of 0-200 T/hr. No other instrumentation
is used for accounting purposes. Grinding circuits are instrumented
to indicate conditions in each individual grinding circuit and to
control the feed rate, i.e. .. classifier load, classifier overflow
density, section feed rate.
e) Process samples are taken automatically during the operating
period at various control points in the Concentrator - Feed, Rougher
Concentrate, Cleaner Tail, Final Concentrate, and Tails.
f) Fluctuations in process may occur when the ore delivering from the
mine is interrupted or when hardness varies. The feed rate to
the ball mills will be varied accordingly. The hardness of the ore
can change doily. Emi;.sions are not affected as there are none.
-------
33
g) Many years - no firm figure.
h) None
3. Roasters
None
4. Reverberatory Furnaces
(a) - (d)
Feed Rate Converter Reverb Cas
Solid chg. (tpd) * Slag (tpd) Volume (ACFM)
Design
Actual
Maximum
700
676
863
NA
475
NA
150,000 @ 600°F
164,000 @ 588°F
NA
* Includes flux, concentrates, precipitates, dusts
Solid charge weighed in feed containers on platform scales. Accuracy
+ 3.0%.
Converter slag is unweighed and is estimated on basis of number ladles
(each estimated to hold 14.5 tons of slag when full) returned to the
furnace. Accuracy + 10%.
Cas volumes obtained from pitot traverse of flue.
e) QF
Furnace smelting zone 2650
Waste heat boiler outlet 580-620
f) Monthly operation - 624 hours (1975)
g) Readings
Instrumentation
Range
Typical
Furnace draft gauge
Fuel flow meters
0.0-pos. 0.1" wc +.03
Oil
Gas
228-1140 gph 1140
55000-177,000 cfm 177,000
Temperature recorder
Boiler Outlet
580-620
600
-------
h)
i)
Material
Sampling
Location
Reverb slag
Matte
Ajo concentrates
Custom conc.
Limerock
Causeof
Fluctuation
Charging cycle
Change in character
of feed
Power outage
Misc. mechanical
fai lures
Skim hole
Matte launder
Ahead & after fiIters
At dryer discharge
In railroad cars
At crushing plant
Frequency
Every 1 5 min.
Twice a week
Once a year
Twice a week
34
Sampling Method
Crab sample in steel cup
Crab sample in steel cup
Automatic samplers
Crab sample from belt
Slit pipe driven thru material
Automatic samplers
Emission
Effect
Peak emissions during charging
Reduced smelting rate reduces
emissions
Reduces emissions
Reduces emissions
j) Indefinite
k) None
Converters
(a) - (0
Design
Actual
Feed Rate
Ctpd)
NA
799*
Cas Converter Operating
Vol. (scfmj ** Temp. (°F) Time (hr. /mo.)
39500
35-42,000
NA
1900-2250
NA
522
* Includes matte, flux, and reverts.
** One converter operation.
Matte to converter is estimated by number of ladles (each containing approxi-
mately 15. 75 tons). Accuracy + 10%. Flux and reverts estimated on assumed
weight per container added. Accuracy +_ 10%.
Cas volumes calculated from pitot tube traverse of exit duct to acid plant.
g)
Readings
Instrumentation
Range
Typical
Blast air flow meter 15-35000 scfm
Temperature Recorder 1900-2250°F
SO2 Recorder 0.0-13.0%
20,000
2150
3-9
-------
35
h)
Material
Sampling
Location
Matte
Slag
Flux
Reverts
Blister Copper
At reverb furnace
At converter
Al crushing plant
Not sampled
Not sampled
Sampling Method
As previously described
Rod sample during skim
Automatic
0
Cause of
Fluctuation
Frequency
Emission Effect
Changing matte grade
Changing air blasts
Matte shortage
A4echanical failure
j) Indefinite - no firm figure.
k) None
Refining Furnaces
(a) - (d)
Feed Rate
(tpd)
Twice a week Low grade prolongs blowing,
increases emissions
Directly related
Curtailment reduces emissions
Emissions may drop to zero
Continually
Twice a week
Once a month
Gas Volumes (scfm)
Oxidizing Reducing
Design
Actual
250
185
NA
NA
1500
7200-1300
Anode product is weighed on platform scales. Error is negligible,
e} Process temperatures are not measured.
f) Refining time - 530 hours per month.
g) None
h)
Sampling
Material Location Sampling Method
Refined copper Casting wheel Crab sample caught in steel spoon
during copper pour.
-------
'i) No fluctuations affecting emissions.
3.6
j) Indefinite
k) None.
C. Emissions
(I) - (3)
Particulate Loading flb./hr)
Emission Sources
Crushing Plant
Reverberatory Process Gas
i) Portion not treatec' in DMA
plant. Vented to main stack
ii) Portion treated in DMA plant.
Converter Process Gas
i) Portion not treated in acid
plant. Vented to main stack.
ii) Portion treated in acid plant.
Vented to main stack.
Fugitive Gas
i) Portion captured by launder
and converter hoods. Vented
to main stack.
ii) Portion escaping hoods
To Control
System
NA
350.6
Nil
NA
NA
Nil
From Control
System
NA
34.2
Nil
108
6.13
Nil
NA
NA
Source of
Test Data
None
(a)
Assumed
(b)
(c)
Assumed
None
None
* Vented fugitive gas does not pass through control systems.
(a) Western Precipitation Inc. precipitator efficiency tests, 10/21-11/2/72.
WP Method 50 test method used, measuring hard particulates only.
(b) Engineering Testing Laboratories tests, 5/19-29/75.
EPA Method 5 used, measuring hard particulates plus acid mist
and metallic sulfates.
(c) Stearns-Roger test (1975), using WP method 50. Hard particulates only.
Main Stack
1) Collects all vented gas except DMA plant gas.
2) Test results by Method 5 have shown particulate loadings of stack
discharge to range between 151 and 647 lbs. /hr., and higher, if
post filter catchments are included.
3) See Attachments (3), (4), (5) for test methods, test data. etc.
-------
37
4. No definitive testwork has been carried out.
5. See Attachment 6- opacity readings.
6. Variances have been due to the following factors:
a) Expected performance of parttcufate control equipment was based on
the ability of this equipment to collect hard particulates only, as deter-
mined by ASTM approved methods of measurement. EPA's prescribed
Method 5, when applied to most smelter gas streams, will collect
sulfuric acid mist and other sulfates as well, which are.weighed as
particulate matter.
b) Stack temperatures on SO2 controlled gas streams are generally
lower than on untreated streams, which aggravates the sulfate con-
densation problem. Intentions to re-heat these gases have been
thwarted by energy restrictions and burner problems.
c) The process weight tables used to determine compliance are inappro-
priate for application to the Ajo smelter.
d) The fluctuating nature of normal smelter operation, plus the ups
and downs in the SO2 control trains, is hard on electrostatic precipi-
tators and tends to reduce their efficiency and accelerate their
deterioration.
There have been no deviations from design specifications or changes in
operating parameters which would significantly contribute to the variances
which have been experienced.
D. Control Systems
1. Descriptions
a) Process treated.
i) Reverberatory furnace gas
The gas stream is first treated for particulate removal in an electro-
static precipitator (see following section) .
At present, approximately 50% of this gas can be further treated
for removal of particulate matter in the scrubbing section of the
DMA (dimethylaniline) absorption plant for SO2 removal. This
equipment consists of a spray chamber, a packed cooling tower,
and an acid mist precipitator. Very efficient particulate removal
is obtained. Tests indicate excellent SO2 removal as well
(165 ppm output) .
Many problems oave been encountered in running this plant.
We are still gathering data to determine the plant's shortcomings
-------
38
D. 1. a) i) Cont'd
Meanwhile, equipment breakdowns are costly and are prevent-
ing operation, thereby removing part of the particulate control
and all of the SO2 control from the reverberatory furnace gases.
ii) Copper converter off gases.
Treated for particulate removal by an electrostatic precipitator
described in a following section.
The gas is scrubbed for further particulate removal and cooling.
A spray chamber (humidifying tower) washes and cools the gas.
A packed cooling tower condenses moisture and removes any
residual solids. Electrostatic mist precipitators are utilized to
remove acid mist droplets. Essentially all of the particulate
material is removed before the gas enters the acid plant for SO2
removal.
SO2 control of the converter gases is achieved with varying
success as the SO2 percentage in the gas varies.
(b) - (c)
Unit Fuet Type Fuef Quantity
Acid Plant Natural gas or No.2 600m cfd natural gas
Diesel Oil or equivalent -
Oil (160-170 gph) .
Although equipped with burners which can burn either natural
gas or No. 2 diesel oil, the electrostatic precipitators are not con-
suming any fuel because of fuel restrictions and mechanical difficul-
ties in the burners themselves.
d) Design parameters (such as the volume, chemical content, and
particulate loading of various process gas streams) were for the
most part established theoretically, although backed up by actual
measurement and experience in some cases. The newly adopted
control processes introduced many new parameters, for which
actual advance measurement would have been impossible.
e) See references in paragraph A (3) above.
f) Normal life of about 20 years will probably be reduced because
of accelerated deterioration due to many process upsets.
g) None.
-------
2. Electrostatic Precipitators
Electrostatic Precipitators
Reverberatory
Converter
a. Manufacturer, type and model
number
b. Manufacturer's guarantees, if any
c. Date of installation or last
modification and a detailed de-
scription of the nature and extent
of the modification:
Western Precipitation, Div.
Joy Manufacturing Company
Type R - No model number.
96.83% of entering particulate subject to
following:
1. At the option of the Company, an outlet
loading of 40 jfhr. will satisfy the
guarantee.
2. The determination of collection efficiency
will be by the Company's standard pro-
cedure as described in Bulletin WP-50.
3. Maximum inlet grain loading of 2 . 25
grains per scf (32°F S 14.7 psia) .
Last modification was addition of Trans-
former-Rectifier unit, Aug. 23, 1973.
Original precipitator had two T-R units, full
wave 45 KV, 1100 MA, voltage primary: 400.
Additiona I T-R uni t added was 87. 5 KVA
with 440V and 210 maximum amperage (1400
MA T-R) . The original installation consisted
of two, one-chamber-wide, two-field-deep
precipitators in parallel. The inlet field of
each precipitator was energized by a common
1100 MA T-R which energised the inlet fields
of both precipitators was replaced with a
1400 MA T-R. The 1100 MA T-R originally
energizing the inlet fields was installed
above the outlet field of one precipitator and
the other 1.100 MA T-R unit that energized
both outlets was reconnected to energize one
outlet field.
Western Precipitation Div.
Joy Manufacturing Company
Type R - No model number.
Converter Cases
97.5% and 41#/hr. under same
statements as for reverb electro-
static precipitator. Maximum inlet
grain loading of 2.10 grains/scf.
No modifications since installed
in 1972.
Ol>
<*o
-------
TF iYJ IS nti
2. Electrostatic Precipitators
Electrostatic Precipitators
Reverberatory
Converter
Description of cleaning and
maintenance practices, including
frequency and method.
Design and actual values for the
following variables: Current -
(amperes)
Voltage -
Rapping frequency (times/hr.)
Removal of dust is done by screw conveyor
which operates with an electric timer set at
30 minutes on and 30 minutes off throughout
the 24 hours.
The collecting plates, discharge electrodes,
and gas distribution plates use MD 850A elec-
tric rappers. The hoppers have been equipped
with air vibrators - hand operated during the
day to eliminate build-ups that may cause
shorts in the electrodes. During shut down
period, (about once per month) the hoppers are
inspected and cleaned out, if necessary.
Broken insulators are changed immediately
upon being detected. Broken wire electrodes
require more time since the chamber must be
isolated and cooled off so that men may go
inside. However, most often, wire electrodes
break and fall clear and do not cause shorts.
1. Two T-R sets rated 45 kv-400 volts,
1100 MA
One T-R sets rated 87.5 kva-400 volts,
1400 MA
2. 440 volts primary-maximum; actual
256 volts primary,
3. Intermittent rapping with 28 electric
rappers complete 15 cycles per hour.
Removal of dust by screw conveyors
continuously. The collecting
plates, discharge electrodes, and
gas distribution plates use MD-8?0A
electric rappers; the hoppers have
been equipped with air vibrators
which are manually operated to
avoid dust build ups .
Hoppers are inspected and cleaned
once per month. Broken insulators
are changed immediately. Broken
wire electrodes require more time
since chamber must be isolated and
allowed to cool. However, wire
electrode breaks are infrequent,
most of the time these fall clear.
1. Three T-R sets rated 45 kv-
400 volts, 1100 MA
Actual amperes: 53 average
2. 440 volts, 3 phase; actual
228 volts primary
3. Intermittent rapping with
40 electric rappers complete
12 cycles per hour.
o
-------
r.DMTROL SYSTEMS - Continued
2. Electrostatic Precipitators
Electrostatic Precipitators
Reverberatory
Converter
(Continued)
Number of banks.
4.
Two
4.
Two
Number of stages
5.
Two
5.
Three
'articulate resistivity
(ohm-centimeters)
6.
We do not have this information.
6.
We do not have this information.
Quantity of ammonia injected (Ibs/hr)
7.
No ammonia is injected.
7.
No ammonia is injected.
I'ater injection flow rate (gals/min)
8.
No water is injected.
8.
No water is injected.
3as flow rate (scfm)-3.02 ft/sec.
9.
Design: 1 50,000 acfm @ 600OF.
Actual: 164,000 acfm @ 588°F.
9.
Design: 210,000 acfm @ 650°F.
Actual: 39,500 scfm (1 converter
)perating temperature (OF)
10.
Design: 600°F maximum
Actual: 450-550°F
10.
Design: 650OF
Actual: 450-650°F
nlet particulate concentration
(Ibs/hr or grains/scfm)
11 .
Design: 2.25 grains max. scf (32°F and
14.7 psia)
Actual: 421 lbs. perhr.*
11 .
Design: 1,079 Ibs/hr.
Actual: 246 Ibs/hr.***
)utlet particulate concentration
(Ibs/hr or grains/scfm)
12.
Design: 0.063 particulate concentration
Actual: 47 lbs. per hour (1975)**
12.
Design: 41 Ibs/hr.
Actual: 6.13 Ibs/hr.***
5ressure drop (inches of water)
13.
0.5 inches of water
13.
0. 5 inches of water negative
* 1975 Tests by Engineering Testing Laboratories, using WP Method 50. Hard particulates only.
** 1975 Tests by Engineering Testing Laboratories, using EPA Method 5 with sulfates deducted.
***1975 Tests by Steams-Roger, using WP Method. Hard particulates only.
-------
D. .Control Systems - Continued
42
3. Fabric Filters
None
4. Scrubbers
Scrubbers are installed after the reverberatory and converter electrostatic
precipitators as further steps in cleaning the gases before their entry into
the DMA and acid plants. Scrubbers of two types are used in series: an
open -type spray chamber (humidifying tower) , followed by a packed
tower (cooling tower). Since the cooling tower performs a very minor
role in particulate removal, information on the humidifying tower only
is reported.
a) The humidifying towers were designed and constructed by Stearns-
Roger, Inc. in collaboration with Monsanto Enviro-Chem Systems, Inc.
No special type designation or model number were specified.
b) Dust collection efficiency of 98% is guaranteed under the specified
operating conditions.
c) The revisions to the towers were completed the week of January 22,
1975 and included: the complete removal of the tray portions of the
towers on the upper dome, the replacement of the stainless steel upper
dome with a carbon steel shell lined with lead and acid brick; and a
complete new spray system with plastic fog spray nozzles.
d) Units are inspected annually. The buiId-up of scrubbing liquid
(weak acid solution) is purged along with the concentrator tailings to
the tailings dam. Repairs to fiberglass weak acid piping and the
Worthington pumps are made as required during operations. As
inspections indicate, plans are made for internal repairs during sched-
uled shut down periods.
e) Scrubbing medium: Weak sulfuric acid at abc-ut 125° F and 0.7%
H2SO4.
Design
Actual
i)
Scrubbing media flow rate (gpm)
1,400
NA
ii)
Scrubbing media pressure (psi)
30
45-50
iii)
Gas flow rate (scfm)
39,800
25-43,000
iv)
Operating temperature (°F)
Inlet
600-700
400-550
Outlet
150
125-150
v)
Inlet particulate loading (Ib/hr)
NA
6.13
vi)
Outlet particulate loading (Ib/hr)
NA
NA'
vii'
I Pressure drop (" WC)
0.27
1.5
-------
43
D. Control Systems - Continued
5. Sulfuric acid plant
a) Plant designed by Monsanto Enviro-Chem Systems, Inc. Single
contact plant. No model number.
b) Guaranteed to produce 7'10 short tons of H2SO4 (100% equivalent)
when supplied with adequate volume of 9.8% SO2.
Effluent gas not to exceed 2500 ppm SO2 when operating at designed
condition.
c) One significant modification has previously been covered in the
description of the changes to the humidifying towers (scrubbers) .
It was determined soon after startup that one mist precipitator was
insufficient for removal of acid mist from the process gas. The two
mist precipitators in the two gas cleaning systems were connected in
series for use in the acid plant gas cleaning train. This gave the
acid plant adequate mist elimination and required the construction
of two additional mist precipitators for the SO2 plant gas cleaning
train. Modification to the acid plant was completed in early July 1974.
d) The plant was originally intended to have a preventative maintenance
program in force at all times. For the most part this has never mater-
ialized. As the acid plant is an integral part of the entire Ajo operation,
major or minor repairs requiring skilled tradesmen must be scheduled.
There is a crew of two full time repairmen that repair and maintain
spare equipment and work on faulty operating equipment as the plant
operations permit.
Three full time instrument men are also employed to keep essential
instrumentation in proper repair.
Each year the entire operation is shut down for major repairs. A
previously arranged private contract is carried out with plant super-
vision to complete a list of repairs and inspections. This repair
period lasts three weeks, normally.
Depending on the smelter operating schedule, the acid plant may
experience two to four shut down days per month. The repairmen and,
if required, tradesmen are scheduled to work on these days to correct
problems or potential problems. Also, there are emergency shut downs
for maintenance.
-------
44
D. Control Systems - Continued
5. Sulfuric acicl plant
e) Catalyst screening should be carried out when needed. Due to prob-
lems in operation which fouled the catalyst, screening has been done
during the annual shut down each of the past three years.
f) York demister pads are used in the absorption tower.
Design
Actual
Production (tpd)
mo
200-425
Conversion (%)
97-98
96-97
Acid strength (%)
93
92-97
Catalyst beos (No.)
4
4
Cas flow rate (scfm)
39,800
35-42,000
Inlet gas temp. (°F) *
102
102
Inlet S02 (%)
6.8-9.8
0-13
Outlet SO2 (ppm)
2500
2400
Acid mist {lb./ton acid)
NA
6.46
Blower pressure ("WC)
\00 Wax.
60-80
* From cooling tower.
6. Liquid SO2
a) Absorption of SO2 by dimethyianaline (DMA) process as developed by
ASARCO. Engineering and construction by Stearns-Roger
Corporation.
fc>) None
c) The addition of a stand-by compressor for SO2 gas was completed in
April of 1975. This spare compressor was intended to reduce
down time due to frequent required repairs of the compressor in
service.
Previous modifications entailed the addition of another two mist pre-
cipitators and the rebuilding of the top of the humidifying (scrubber)
tower. Both of these changes have already been covered.
Construction of the plant was initially completed in November of 1972.
d) There has not been enough operation of the plant to establish definite
practices. When in operation, the plant is washed down as often
as needed to prevent excessive buildup from acid spills or dimethyi-
analine spi lis.
-------
45
D, Control Systems - Continued
6.-d) Cont'd.
Periodic equipment inspection and instrument readings give
indications of possible problems or needed repairs. Repairs that
can be delayed until scheduled shut downs are completed at these
times; otherwise, the plant is shut down when problems occur and
the required personnel are brought in to do the repairs.
A certain amount of preventative maintenance is carried out by two
repairmen who serve both the SO2 and acid plants.
e) DimethylanaIine (DMA) .
f) Design Actual
Production (tpd) 60-90 Uncertain
Gas flow rate (scfm) 41 ,000 NA
Operating temperature* 90 90
Inlet SO2 concentration 1-10 0.5-1.5
Outlet SO2 concentration 500 165 ppm
Acid mist (lbs.H2SO4)/ton SO2** Nil Nil
* From cooling tower.
**Assumed.
7. Refer to references in paragraph A (3) .
8. Instrumentation
a) Acid Plant
Inlet: i) DuPont SO2 Analyzer Model 160 B.
0-15% SO2 (instrument range)
3-6% SO2 (typical matte blow)
5-9% SO2 (typical copper blow)
Location: On converter precipitator discharge.
ii) Leeds & Northrup SO2 Analyzer
Model 7802-D-A2
0-15% SO2 (instrument range)
Typical range: as above
Location; discharge of acid plant blower.
Outlet: DuPont SO2 Analyzer Model 100
0-0.5% SO2 (instrument range)
0-2-0.3% SO2 (typical)
Location: Tjil gas duct about 100' from absorbing tower.
-------
D. Control Systems - Continued
46
8. Instrumentation (Cont'd)
b) S02 Plant
Inlet: i) Served by same DuPont instrument as inlet acid plant
whenever converter gas is diverted to SO2 plant,
ii) DuPont SO2 Analyzer Model 460B
0-15% SO2 (instrument range)
1. 5-2.5% SO2 (typical)
Location: Discharge of SO2 plant blower.
Outlet: DuPont SO2 DMA Analyzer Model 461 C
0-2000 ppm SO2 instrument range
0-50 ppm DMA instrument range
150-200 ppm SO2 (typical)
15-20 ppm DMA (typical)
Location: Top of SO2 pJant absorption tower.
c) Main Stack
Outlet (Located 127' up on 360' stack)
i) DuPont SO2 Analyzer Model 460
0-10% SO2 (instrument range)
1-1.5% S02 (typical)
ii) Lear Siegler Optical Transmitter,
. Model #20-200
0-100% opacity (instrument range)
100% (typical)
9. Acid Plant
a) Possible flame out in heating unit for acid plant catalyst chamber.
If there is insufficient feed gas for autothermal operation (continuous
supply-39,000 scfm of 6.5% SO2 gas), the plant operating heat will be
lost and a period of time is required to refire the heater and build up
the plant heat. During this time any converter gases will have no SO2
control and reduced particulate control. This may occur at any time,
but is infrequent.
b) Insufficient heat exchanger capacity to cool the amount of acid being
produced will cause a reduction in production. This will require sorru
of the converter gas to be released to the atmosphere, giving slightly
less SO2 and particulate control. This is a frequent occurrence.
c) One of the acid circulation pumps could fail. This causes a shut down
of the acid plant and SO2 plant as well. No SO2 control will be
achieved until a crane can be scheduled to install the spare pump.
This has occurred approximately five times in three years.
-------
47
D. Control System - Continued
9. Acid Plant (Cont'd)
d) If one of the two primary gas blowers should fail for any reason,
production would be reduced to about one-third of normal. The pro-
cess gas emitted from the smelter converters would be higher in
SO2 and particulate matter until the problem was corrected. On
several occasions this mishap has occurred.
e) Electrical shorts could negate the particulate recovery from the
electrostatic precipitators serving the acid plant. This could cause
a reduction in acid production or even a complete stoppage if the
problem were serious enough. Shorts have been frequent but have
never caused the plant to be shut down.
f) A leak in any one of the many acid lines would cause an immediate halt
or curtailment in production. Reduced SO2 control and reducted par-
ticulate control would be the result until the leak could be fixed. This
problem has been bad at times and non-existent at others. The problem
may occur as frequently as once a week.
SO2 Absorption Plant
The plant could shut down for any of the following reasons:
a) Blower failure
b) Critical pump failure (8 pumps are critical)
c) Compressor failure, unless the spare is available.
d) Loss of steam.
e) Leaks in the acid, DMA, soda ash, water, or SO2 gas or liquid lines.
All of these have been troublesome. The most frequent are compressor
failure and acid leaks which may happen once or twice a week. The
effect of these problems is to reduce the SO2 and particulate control.
E. Stacks
I. The 360-foot concrete stack is of tapered reinforced concrete construction.
It is lined with acid-resisting brick laid in acid-proof mortar and has
2-inches of fiber glass insulation between the concrete and the brick lining.
Units exhausted through the stack are: non-treated reverberatory furnace
gases, non-treated converter gases, acid plant tail gases, smoke hood
(hoods over three converter hoods) exhaust system and the exhaust system
for the matte launders, matte ladle tunnel and reverb slag launder.
-------
Stacks - Continued
2.
a) Height (feet above terrain) 360
b) Elevation of discharge points (feet above
sea level) 2104
c) Inside diameters (ft)
Bottom 24.27
Top 10.75
d) Exit gas temperatures (°F) 212
e) Exit gas velocities (ft/sec) 25.8-29.
January 1976
-------
SPECIFICATIONS:
Ajo
No.
BTU/Gal
% Sulfur
% Ash
2 Fuel
Ranee
129,323 - 140,600
.23 - .50
-0- - .01
Specific Gravity: .8155 - .8654
Consumption
37,039 Bbls.
Typical
l'iS.OOO
.31
.01
.8424
Average
j>,/x 10
//
DRW - No. 6 Fuel
Range Typical Average
BTU/Gal : 152,381 - 153,095 153,000
% Sulfur: .90 - .98 .95
% Ash : .03 - .05 .04
Specific Gravity: .9937 - .9951 .9946
Consumption : 103,101 Bbls.
Morenci - Nos. 4 - 5 - 6 - Kerosene:
Range Typical Average
BTU/Gal : 137,038 - 145,693 1*2,000
% Sulfur: .15 - .77 .42
% Ash : -0- - .001 .001
Specific Gravity: .8121 - .9198 .8725
Consumption : 285,281 Bbls.
J SPECIFICATIONS:
Percentage Composition
Helium
Carbon Dioxide
Nitrogen
Methane
Ethane
Propane
Iso-Butane C^
N-Butane
Iso-Pentane i
N-Pentane n C5
Total
S1
c2
C3
n C 4
Cs
Density:
BTU/CF :
Percent Sulfur
Consumption
Ajo
DRW
Morenci
MOL. %
.02
.20
1.28
89.49
7.29
1.48
.08
.14
.01
.01
10 u. UU7«
.047 Lbs./SCF
1,064
0.0006 Grains/SCF
1,547,865 MSCF
3,516,346 "
5,101,069. "
/,bx/o sro6
-------
Attachment 2
Composition of Materials Treated In the Ajo Smelter
Concentrates
Component
Ajo
Tyrone
Bagdad
Bruce
Tyrone
Precipitate
Lime-
Rock
Mixed
Flux
Cu (1)
(2)
30.07
27.16-32.56
19. 36
16.66-23.44
32.5
30.10-33.89
24.99
23.87-25.99
74.79
66.86-81.45
-
-
Si02
8.5
7.4-9.6
4.8
3.1-7.8
5.4
3.6-7.1
1.6
1.2-2.6
1.7
1.1-2.9
3.3
2.4-4.2
79.8
76.6-81.7
ai2o3
3.1
2.6-3.5
2.2
1.8-2.6
2.0
1.1.-3.0
0.5
0.1-0.7
3.0
2.0-4.0
1. 3
0.7-2.2
8.3
5.1-9.7
Fe
24. 7
23.2-25.9
30.8
27.4-32.2
25.9
23.9-27.5
26.0
25.3-27.2
6.3
3.6-9.6
0.5
0.5-0.6
2.2
1.6-3.5
5" "
29.8
28.9-30.4
40. 3
37. 3-41.7
31 .7
30.2-32.6
32. 3
31 .5-32.8
_
—
—
CaO
0.9
0.8-1.1
0.4
0.1-0.6
0.3
0.1-0.9
0.2
0.1-0.9
51 .9
50.2-55.2
1 .4
1.0-1.9
Pb
~ •
:
2.8
1.7-4.0
_
Zn
. —
—
8.6
7.8-9.5
MgO
-
-
7 '
-1
i:
0.8
0.6-1.1
-
(1) ^Averaqe
(2) Range
-------
Appendix C
SIP Regulation Applicable
To Phelps Dodge
-------
RULES AND REGULATIONS
52
Subpart D—Arizona
§ 52.124 [Kcvokcd]
1. Section 52.124 is revoked.
2. Section 52.126 is amended by add-
ing paragraph (b) as follows:
§52.126 Control strategy anil regula-
tions: particulate matter.
• • * » •
(b) Replacement regulation for Regu-
lation 7-1-3.6 of the Arizona Rules and
Regulations for Air Pollution Control,
Rule 31 (E) of Regulation III of the Mari-
copa County Air Pollution Control Rules
and Regulations, and Rule 2ounds (pounds (pounds
per hour) per hour) per hour) per hour)
60 0.30 00,000 29. GO
100 0.55 80.000 31.10
600 1.63 120,000 33.28
]r000 2.25 100.000 3185
6,000 6.3S • 200.000 3fi. 11
10r000 9.73 400,000 40.36
20,0001 14.99 1,000,000 40.72
(i) Interpolation of the data in the ta-
ble for process weight rates up to GO,000
lbs/hr shall be accomplished by use of
the equation:
£ = 3.59 P"-a P< 30 tons/h
and interpolation and extrapolation of
the data for process weight rates in ex-
cess of 60,000 lbs/hr shall be accom-
plished by use of the equation:
£ = 17.31 P».'» P> 30 tons/h
Whero: E^Enilsslons In pounds per hour
P— Process welGht In tons per hour
(il) Frocess weight is the total weight
of all materials and solid fuels introduced
into any specific process. Liquid and
gaseous fuels and combustion air will
not be considered as part of the process
weight. For a cyclical or batch operation,
the process weight per hour will be de-
rived by dividing the total process weight
by the number of hours in one complete
operation from the beginning of the
given process to the completion thereof,
excluding any time during wliich the
equipment Is Idle. For a continuous op-
eration, the process weight per hour will
be derived by dividing the process weight
for a given period of time by the num-
ber of hours in that period.
(iii) For purposes of this regulation,
the total process weight from all similar
units employing a similar type process
shall be used in determining the maxi-
mum allowable emission of particulate
matter.
(2) Paragraph (b)(1) of this section
shall not apply to incinerators, fuel
burning installations, or Portland cement
plants having a process weight rate in
excess of 250,000 lb/h.
(3) No owner or operator of a Port-
land cement plant in the Phoenix-Tucson
Intrastate Region (§81.36 of this chap-
ter) with a process weight rate in excess
of 250,000 lb/h shall discharge or cause
the discharge of particulate matter into
the atmosphere in excess of the amount
specified in § 60.62 of this chapter.
(4) Compliance with this paragraph
shall be in accordance with the provi-
sions of $ 52.134(a).
(5) The test methods and procedures
used to determine compliance with this
paragraph are set forth below. The meth-
ods referenced are contained in the ap-
pendix to part 60 of this chapter. Equiv-
alent methods and procedures may be
used if approved by the Administrator.
(i) For each sampling repetition, the
average concentration of particulate
matter shall be determined by using
method 5. Traversing during sampling
by method 5 shall be according to meth-
od 1. The minimum sampling time shall
be 2 hours and the minimum sampling
volume shall be 60 ft3 (1.70 m1), cor-
rected to standard conditions on a dry
basis.
(ii) The volumetric flow rate of the
total effluent shall be determined by us-
ing method 2 and traversing according to
method 1. Gas analysis shall be per-
formed using the integrated sample
technique of method 3, and moisture
content shall be determined by the con-
denser technique of method 4.
(iii) All tests shall be conducted while
the source is operating at the maximum
production or combustion rate at which
such source will be operated. During the
tests, the source shall burn fuels or com-
binations of fuels, use raw materials, and
maintain process conditions representa-
tive of normal operation, and shall op-
erate under such other relevant condi-
tions as the Administrator shall specify.
3. Section 52.120 Is amended by add-
ing paragraphs (c) and (d) as follows:
FEDERAL REGISTER, VOL. 38, NO. 92—MONDAY, MAY 14, 1973
-------
Appendix D
Example Calculations of
Gas Flow Rates
-------
Mowrate at Standard Conditions
piVi . PsVs or Vs ¦ Pi * Ts x
Ti Ts Ps T1
where: = given pressure
V. = given gas volume
T. = given temperature in ° R
P$ = pressure @ std condns (14.7 psi or 760 mm Hg)
Vs = gas volume @ std condns (in same units as )
Ts = temperature @ std condns (530°R)
Reverb ESP Design^
Vs = 13.8 x 530 x 150,000 acfm
14.7 1,060
Vs = 70,400 scfm
Converter ESP Design^
V„ = 13.8 x 530 x 210,000 acfm
s 14.7 1,110
Vs = 94,100 scfm
Reverb ESP Actual
V. = 13.8 x 530 x 164,000 acfm
s 14.7 1,048
Vs = 77,900 scfm
Reverb ESP Actual w/o Pressure Correction
V = 530 x 164,000 acfm
S 1,048
Vs = 82,900 scfm
X 4-
DMA Plant Corrected for Pressure
V„ = 13.8 x 41,000 acfm
s 14.7
Vs = 38,500 scfm
+ Reference 3
ft Reference 1
------- |