EPA-600/2-76-036h
February 1976
Environmental Protection Technology Series
DESIGN AND OPERATING PARAMETERS
FOR EMISSION CONTROL STUDIES:
Phelps Dodge, Douglas, Copper Smelter
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate 'urther development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment, and methodology to repair or prevent
environmental degradation from point and non-point sources of pollution. This
work provides the new or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental
Protection Agency, and approved for publication. Approval
does not signify that the contents necessarily reflect the
views and policy of the Agency, nor does mention of trade
names or commercial products constitute endorsement or
recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service,-Springfield, Virginia 22161.
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EPA-600/2-76-036h
February 1976
DESIGN AND OPERATING PARAMETERS
FOR EMISSION CONTROL STUDIES:
PHELPS DODGE, DOUGLAS, COPPER SMELTER
by
I. J. Weisenberg and J, C. Serne
Pacific Environmental Services, Inc.
1930 14th Street
Santa Monica, California 90404
Contract No. 68-02-1405, Task 5
ROAP No. 21ADC-061
Program Element No. 1AB013
EPA Project Officer: R. D. Rovang
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
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TABLE OF CONTENTS
Page
A. INTRODUCTION AND SUMMARY 1
B. PLANT LOCATION, ACCESS AND OVERALL GENERAL ARRANGEMENT . 1
C. PROCESS DESCRIPTION 5
D. EMITTING EQUIPMENT 6
a. Roasters 6
b. Reverberatory Furnaces 8
c. Converters 15
d. Sponge Iron Plant 16
e. Anode Furnaces 17
f. Other Emitting Equipment 18
E. EXISTING CONTROL EQUIPMENT 18
F. GAS SYSTEM DUCTWORK 20
G. SULFUR BALANCE AND GAS COMPOSITION AT SYSTEM EXIT .... 20
H. GAS CHARACTERISTIC VARIATION 28
I. STACK DESCRIPTION 29
J. PRESENT TECHNIQUE FOR SOLID WASTE HANDLING 30
K. FOOTING AND STRUCTURAL REQUIREMENTS 30
L. EXISTING AND POTENTIALLY AVAILABLE UTILITIES 30
M. POTENTIAL NEW CONTROL EQUIPMENT INSTALLATION PROBLEMS . . 31
REFERENCES 32
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LIST OF FIGURES
PAGE
1. LAND CONTOUR MAP OF SMELTER AREA (USGS MAP) 2
2. OVERALL SMELTER GENERAL ARRANGEMENT .... 3
3. PROCESS FLOWSHEET AND SULFUR BALANCE 7
4. ROASTER DUST & GROUND SMOKE COLLECTION SYSTEM ...... 21 '
5. REVERBERATORY PRECIPITATORS & ROASTER PRECIPITATORS & FLUES 22
6. WASTE HEAT BOILER DOWNCOMERS - GENERAL ARRANGEMENT ... 23
7. ELECTROSTATIC PRECIPITATORS - GENERAL ARRANGEMENT .... 24
LIST OF TABLES
1. GAS STREAM CHARACTERISTICS 26
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A. INTRODUCTION AND SUMMARY
The purpose of this report is to present background design data on
the Phelps Dodge Douglas smelter operation at Douglas, Arizona in
sufficient detail to allow air pollution control system engineering
studies to be conducted. These studies are primarily concerned with
lean S0_ streams that are currently not being captured.
Physical layout of the smelter and surrounding area along with existing
smelter and control equipment is presented. Ductwork that would be
considered for future system tie-in is defined. Emissions from operating
equipment, gas flow rates, temperatures, sulfur balance and process flow
sheet are included. Utilities, stack dimensions, footing requirements,
and solid waste handling are defined. Available area for new control
equipment, gas characteristic variation and potential new control
equipment installation problems are discussed.
There is presently no S0_ control at this smelter. The major uncontrolled
sources of SO. and particulate being the roasters, reverberatory furnaces
and the converters. Approximately 488,852 tons per year of SCL (Ref. 1)
and 13,634 tons per year of particulate are emitted. There appears to
be sufficient space and utility availability to install additional
control equipment although distance from the smelting operation
and structural interferences could increase cost and operational
problems.
B. PLANT LOCATION, ACCESS AND OVERALL GENERAL ARRANGEMENT
The Phelps Dodge Douglas smelter is located approximately 1^ miles from
the town of Douglas, Arizona and less than 1 mile from the Mexican border.
Figure 1, reproduced from a USGS map, shows the topography of the
immediate area. The plant site elevation is 3,945 feet MSL. The plant
site coordinates are latitude 31° - 21' N and longitude 109° - 35' W.
The overall plant site is shown in Figure 2.
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32'3
ARIZONA
SONORA
Figure 1
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FIGURE 2
OVERALL SMELTER GENERAL ARRANGEMENT DRAWING
( Located in pocket inside of back cover)
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The Douglas Reduction Works consists of the smelter and allied
facilities required for the treatment of the direct smelting under-
ground ores, concentrates, and precipitates produced by the Copper
Queen Branch of Phelps Dodge Corporation. In addition to these
materials, the smelter treats a considerable tonnage of custom and
toll materials which include scrap brass, refinery slags and copper
precipitates. Production is shipped by rail to Phelps Dodge Corporation
refineries at El Paso, Texas and Laurel Hill, New York.
The mine receipts are in general low grade and have a considerable
excess of sulfur over that required for efficient reverberatory
furnace and converter operation. For this reason it is necessary
for this smelter to roast the greater part of the mine receipts.
Major units in the smelter include:
1. Preparation Department and
Scrap Brass Plant
2. Roasters (24)
3. Reverberatory Furnaces (3)
4. Converters (5)
5. Sponge Iron Plant (Now on Standby)
6. Anode Plant
7. Power House
1
Much of the following is taken verbatim from Reference 2.
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The pollution control equipment consists of four parallel electro-
static precipitators handling the gases from the 24 roasters, a
balloon flue and three parallel electrostatic precipitators for
the gases from the reverberatory furnaces and a balloon flue and
four parallel electrostatic precipitators for the gases from the
converters. Roaster and reverberatory furnace gases are discharged
to a 544 foot stack. Converter gases are discharged to a 564 foot
stack.
As seen in Figure 2, available space for new control equipment can
be found adjacent to the roaster-reverb stack. Space east of the
old roaster Cottrell precipitator or north of the new roaster and
reverberatory furnace precipitators could be utilized. Distance from
the smelting operations will require additional connecting duct-
work resulting in additional initial cost and possible operational
problems.
C. PROCESS DESCRIPTION
Feed to this smelter consists primarily of ore from Phelps Dodge at
Tyrone and custom ore from the Cypress - Pima Mines.
The prepared and mixed feed is fed from separate 100 ton feed bins
by two vane drum feeders controlled by variable speed adjustment on
the feeder drive.
There are 24 seven hearth Herreschoff roasters arranged in two parallel
rows of 12. Gases from the roasters pass to recently installed electro-
static precipitators (99% efficiency) and then are combined with the
reverberatory furnace offgases and pass to the 544 foot stack. Dust
collected in the precipitators is returned to the roasters. Calcines
from the roasters are taken by electric trolley to three reverberatory
furnaces; two bath smelting and one side-charge. Furnace charging
rates are in the range of 900 to 960 tons of calcine per day. The
furnaces use natural gas fuel.
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Gases from the reverberatory furnaces pass through waste heat
boilers and then to a balloon flue and finally are treated in
new electrostatic precipitators to remove 99% of the dust
(neglecting sulfates). Dust from the precipitators and from the
balloon flue is returned to the roaster.
Matte from the reverberatory furnaces is converted to medium blister
copper in five 13' x 30' Peirce-Smith converters. Normal operation
requires 3 operating converters with service rotated among four hot
converters to maximize blowing time. The blister copper from the
converters is taken by ladle and charged to anode furnaces. Reducing
gas and air are charged to these furnaces for further refinement of
the blister copper. Copper from the anode furnaces is cast. Gases
from the converters are collected by conventional overhead hoods and
pass through a balloon flue to electrostatic precipitators before
going to the 564 foot converter stack. A collection efficiency of
96.5% (neglecting sulfates) is reported for this precipitator.
The dust collected in this precipitator is recycled back to the
roasters. Slag from the anode furnaces is returned to the converters.
Slag from the converters is returned to the reverberatory furnaces.
Slag from the reverberatory furnaces is taken to the dump by electric
car. Temperatures, volumetric gas flows and SO^ percentages are
shown on the process flow sheet, Figure 3. .
D. EMITTING EQUIPMENT
a. Roasters
The Roaster Plant consists of twenty-four, seven-hearth Herreschoff
roasters arranged in two parallel rows of twelve roasters. Only
18 are normally in operation at a time.
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Converter Off-Gas\
210-265,000 SCFM \
1.1 TPD Du
245.7 TPD
1.4-1.8Z SO_ /.
lust I ».
i-S as SO /
en /
PACIFIC ENVIRONMENTAL SERVICES, INC
Process Flow & Sulfur Balance Sheet
Phelps Dodge Corp./Douglas Branch
prepared 10/75
Figure 3.
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Each roaster is fed from a separate 100-ton feed bin by two
vaned drum feeders, controlled by a variable speed adjustment
on the feeder drive. The feed bins are equipped with air
vibrators which automatically rap the bins on a timed sequence
to aid in feeding.
The roasters are standard Herreschoff with a shell diameter
of 21* - 7". The seven roaster hearths consist of a dry floor
and six inside hearths. Natural gas is introduced on the fifth,
or next to bottom, hearth for supplemental heat in roasting.
Column air is discharged into the roaster on the bottom or sixth
hearth. Calcine discharges from each roaster into a holding
hopper over the calcine haulage tracks.
Sixteen to twenty roasters are usually in operation. Charge
averages 170 to 180 dry tons per roaster day at a fuel ratio
of 0.41 to 0.48 million BTU per ton.
Present practice is to use castable refractories in making hearth
replacements. Sidewalls remain fireclay brick. The rabble arms
and rabbles on the lower three hearths are heat resistant cast
steel.
Calcine produced in the roaster plant is transferred to the
reverberatory furnace by rail. Two trains of two and four 15-ton
calcine cars are used to pull the calcine hoppers fifteen times a
shift, weigh the calcine on track scales and spot the cars for
unloading at the reverberatory furnaces.
b. Reverberatory Furnaces
Three reverberatory furnaces are used for smelting operations;
two bath smelting furnaces and one side-charge. All furnaces
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have the nominal inside dimensions of 26' x 103' to 107'. The
two bath smelting furnaces are of sprung silica arch construction
whereas the side-charge is a suspended basic roof furnace.
All reverberatory charge, except for some cold silica flux, is
calcined. Since the side charge furnace operates on a relatively
coarse charge, and the bath smelting furnaces operate better on
a fine charge, two roaster charges are used, fine charge contains
approximately 50% concentrates and coarse charge containing about
20 to 25% concentrates. The charge to the roasters contains
28% - 30% sulfur, and the calcine to the furnaces contains 14 -
14.5% sulfur. Calcine temperatures are maintained at 1050 to
1100°F.
No. 8 Side-Charge Furnace
Construction
The roof is a flat roof of Detrick construction. Lengthwise,
the roof is horizontal with the exception of twelve feet at the
firing end which was sloped down to clear the calcine haulage
track support structure. Furnace sidewalls and uptake walls
are basic magnesite-chrome brick. Alternating clad - unclad
construction was used in the roof and exposed interior furnace
walls. The bottom is 2' - 2" of poured slag.
A single Babcock-Wilcox four drum Sterling waste heat boiler,
rated at 2568 BHP - 85,000 pounds steam per hour, is superimposed
over the end of the furnace. The furnace opens directly into
the boiler with no provision for bypassing the boiler. Retractable,
air motor driven soot-blowers and hand lancing are used to maintain
the boiler passages.
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Charging Calcine
The side-charge charging system consists of two enclosed
drag-chain conveyors at the sides of the furnace running 60
feet from the bridgewall. Distribution of calcine is through
gate valves and charge pipes spaced at four foot intervals
between the buckstays the length of the drag box. Both sides
are charged at the same time on a 32 minute cycle. Charge gates
are operated using air pistons controlled either manually or by
use of an automatic, cycled timing system.
Matte Tapping
Matte is tapped through the sidewalls beyond the charge zone
into launders which carry it to ladles in the converter aisle.
Tapping is alternated among four tap holes, two to a furnace
side.
Converter Slag
Converter slag is charged through two fixed launders at the
sides of the bridgewall.
Furnace Slag
Furnace slag is skimmed through the center of the end wall
under the boiler into a short launder leading to the slag car.
Water cooled jackets are used to maintain the notch.
10
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Firing
The side-charge furnace is fired with natural gas through
the bridgewall using four high pressure 10-in. inspirating
burners at a rate of 125,000 to 135,000 CFH. Smaller
supplemental burners are used in the sidewalls to maintain
bath temperature at the boiler end. An emergency fuel oil
system can be used in place of the natural gas.
Bath Smelting Furnaces - No. 9 and No. 10
Construction
Sidewalls and arch are of silica brick with the arch drooping
down as it approaches the boiler uptake.
The furnace hearth consists of a fused impervious layer of chrome
ore and magnetite approximately six to seven inches thick placed
on top of a poured slag subjacent hearth.
The matte retaining crucible consists of an 18-inch thick tamped
periclase lining backed by silica brick supported by the buckstays.
The slag zone above the crucible falls within a water jacketed
wall. Jackets are cast copper, 20 inches high, with cooling coils
embedded in them. The cooling water is circulated in a closed
system between the furnace and power house heat exchangers and
pumps.
Two separate 1120 BHP waste heat boilers rated at 34,000 pounds
per hour steam are used for waste heat recovery from the No. 9
furnace, while the No. 10 boilers are rated at 30,000 pounds
steam. Gases pass from the furnace uptake through short cross-over
11
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flues into each boiler which can be isolated from the furnace
by use of dampers. Air operated soot blowers are installed on
each boiler. Those on the No. 10 boilers are the retractable type.
Charging Calcine
The bath smelting furnaces are each equipped with four Wagstaff
feeders located two on each sidewall of the furnace near the
bridgewall. Charging ports are covered with air-operated, cast-
refractory doors when not in use. Charging is rotated among the
guns on 16 minute cycles.
Matte Tapping
Matte is tapped through the sidewalls near the burner end of the
furnace. Each furnace has four tap holes among which tapping is
alternated.
Converter Slag
Converter slag is charged through two launders at the sides of
the bridgewall. Launders are fixed in position, angled to toe
in slightly toward the center of the furnace. Heat resistant
cast steel lips are used within the bridgewall.
Furnace Slag
Slag skimming is similar to the side-charge furnaces.
12
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Firing
Firing is with natural gas at a rate of 135,000 CFH through
six high-pressure 8-in. inspirating burners located in the
bridgewall, augmented by sidewall burners. A standby oil
burner system can be used in place of natural gas.
Operation of Furnaces
All three operating furnaces receive the same charge, the
calcine trains being rotated through the operating roasters
to minimize charge variation. Charging rates are currently:
Tons Calcine/Furnace Day Mil. BTU/Ton
Side Charge 910-930 3.78
Bath Smelting 900-960 3.50
Furnace combustion is controlled to maintain 0.4 to 0.5% 0_ at
a point within the furnace approximately 10 feet from the uptake.
All furnaces have automatic draft controllers operating dampers
on the boiler outlets. Side-charge furnace pressure is maintained
at 0.005 inches of water draft, the bath furnaces at 0.015 draft.
Slag disposal in the past was a major problem due to a very low
grade smelter input. Increased grade of input in recent years
has lessened the materials handling problem, but an average of
150-170 pots of slag a day is taken from the furnaces. Slag
haulage is done by two 25-ton diesel-electric locomotives
operating in tandem working with six 225 cu. ft. slag cars.
The locomotives push a loaded train of three pots to the dump
each trip and leave three empty pots under the furnace slag
launders for filling. Through the use of spring switches and
13
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a reversing track layout, the slag train is reversed on the
return trip so that the locomotive can pick up the now loaded
pots and leave the emptied pots.
Furnace gases pass through a flue system to the roaster-reverb
stack which is 544' high with a 22'-7" diameter discharge.
Maintenance of Furnace Refractories
Sprung Silica Arch Furnaces
The silica .arches and sidewalls of the furnaces are maintained
by hot patching with a silica slurry, a method developed at the
former United Verde Branch.
At this smelter, the barren 90 to 93% silica rock used as flux
is used for hot patching. The crushed rock is ground in a ball
mill to 86 to 90% minus 200 M to produce a slurry containing
53 to 60% solids.
The slurry is stored in a 10,000 gallon tank containing an agitator
from which it is pumped into a 4-inch rubber lined distribution
loop over the top of the furnaces. Distribution to the work
areas is through down-comers located at the furnace sides and
rubber hoses.
The slurry is sprayed through pipe nozzles onto the brickwork by
the use of plant air at the nozzle.
14
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Converters
Matte from the reverberatory furnaces is converted to medium
blister copper in five 13 x 30 ft. Peirce-Smith converters.
Normal operation requires three operating converters with
service rotated among four hot converters to maximize blowing
time. Additional converter shifts are scheduled as needed.
Converters No. 1 through 4 have 42 two-inch tuyeres spaced on
six inch centers. Riding rings placed within the shell limit
the number of tuyeres. These converters are equipped with
Gaspe mechanical tuyere punchers. The No. 5 converter, with
riding rings at the ends of the shell, has 24 three-inch tuyeres
and is equipped with the Mprenci style hydraulic tuyere puncher.
Blowing air at the converter is approximately 12.7 psi. The
Morenci puncher will be replaced in the near future with
standardization on the Gaspe puncher for this operation.
Four overhead cranes service the converter aisle. The two
center cranes have 60 ton capacity hoists, where the outer
cranes are of 40 ton capacity. The cabs are air conditioned.
Operational communications use a low power FM radio system.
Material handling boats, clamshells and not metal ladles are
so designed that nearly all hookups may be made from the crane
eliminating dangerous floor work by men.
Siliceous flux is charged to the converters in the slaging blow
through the mouth from an inclined chute fed by a pan feeder under
the flux bin. Flux charging is controlled by the skimmer.
Oxygen enrichment of the blowing air is practiced on a limited
scale to aid in smelting secondaries.
15
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The Converter Department makes a minor amount of shot copper
for use in Phelps Dodge Corporation refineries.
d. Sponge Iron Plant
Two 25 TPD sponge iron plants have been operated at this smelter.
They are currently on stand-by status.
Ferramag, a mixture of iron oxides is produced by blowing a
converter charge of matte without adding silica flux. The
ferramag is granulated by pouring into a water stream with the
resultant product serving as the feed to the sponge iron plant.
The sponge iron plant converts the ferramag to approximately
60% metallic iron by reducing with air reformed natural gas in
a reducing furnace. The sponge iron was used in the Copper
Queen Branch precipitation plant at Bisbee.
Each plant includes the following:
1. A 40-foot long, four-foot diameter kiln for
drying and preheating ferramag.
2. A vertical reducing furnace.
3. A natural gas-air reformer.
4. Auxiliary materials handling equipment.
16
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Anode Furnaces
The anode furnaces oxidize the blister copper to remove the
remaining sulfur and slag forming impurities. The oxidized
copper is then reduced using reformed gas to less than 0.10
per cent oxygen and cast as 750 pound anodes for shipment
to the Phelps Dodge Corporation refinery at El Paso, Texas.
Anodes average 99.6% copper. The anode furnaces generate a
small amount of S0_ and particulate matter.
The department has two 13 x 28 ft. basic lined furnaces similar
in design to the Peirce-Smith converters, a circular 22-mold
casting wheel, and a natural gas-air reformer.
The oxidation and reducing steps are accomplished by introducing
plant air or reformed gas into the bath through two 1-% in.
tuyeres at a pressure of 15 to 20 pounds. A four-way valve is
used to change from one gas to the other or to vent to atmosphere.
Reformer operation is automatic. Two operating panels with
start-stop buttons, equipment signal lights and gas flow recorders
are used to control reformer operation from the anode furnace floor.
A pressure-loss, fail-safe design will introduce natural gas into
the tuyeres should there be a failure. Approximately 0.324 million
BTU are required per ton anode copper.
The use of reformed gas for the anode copper reduction step was
developed at this plant in 1958. The present plant has been in
operation since early 1959 with no significant interruption in
anode production due to reformer maintenance.
The finished anode copper is poured from the anode vessel into
a tilting spoon which in turn is tilted to fill the molds.
Furnace movement, positioning of the reversible casting wheel,
17
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spoon operation and mold washing are controlled by one man.
Pulverized silica or zinc oxide is used as the mold wash and
water sprays and air jets are used to cool the molds. The
solidified copper anodes are broken from the mold and transferred
to a bosh tank for final cooling using air operated hoist and
hooks. Casting rate is approximately 25 tons per hour.
Anodes are removed from the bosh tank by use of an overhead
crane. Following trimming and inspection, the anodes are loaded
for shipment.
f. Other Emitting Equipment
Material handling mixing and preparation in the bedding plant
can produce some fugitive particulate.
Leaks in ducts, roasters, and at the reverberatory furnace openings
can generate SCL and particulate. The condition of the roasters is
particularly poor and they do generate fugitive SO- emissions.
Ladles holding matte and slag produce visible emissions.
E. EXISTING CONTROL EQUIPMENT
Gas from the 24 roasters is drawn into a brick and tile lined flue
running the length of the building and discharging into the header
flue. Initial dust collection is made in the series of dust hoppers
forming the flue bottom.
18
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Four new parallel electrostatic precipitators have been installed,
replacing an old six chamber Cottrell precipitator, for treatment of
the roaster gases.
Cleaned gas from the precipitators discharges into a flue leading to
the roaster-reverberatory furnace stack. Approximately 99% of the
dust entering the precipitators (neglecting sulfates) is recovered
and transported by conveyors back to the roaster plant where it is
charged on to the fifth hearth of six of the roasters or pugged and
returned to a dust hopper from which it can be pulled directly into
the calcine trains.
Three new parallel electrostatic precipitators have been installed
to treat the reverberatory furnace gas steam.
Gas from the converters passes through a balloon flue and four
parallel electrostatic precipitators to the separate converter stack.
Each converter is equipped with a hood and a jug damper, permitting
the closing off of inactive converters. Balloon flue dust is returned
to the converters while precipitator dust is placed on the roaster beds
in the bedding plant. The converter hood system is currently being
replaced.
There is presently no SCL control employed at this smelter even though
a large chamber sulfuric acid plant had been built in 1917. This
plant was used until 1945 when it was shut down and later dismantled
because it was making only low-grade acid and there was not sufficient
market to justify its operation. Also, it was necessary to feed the
roasters with an ore high in pyrite which was mined separately at
Bisbee for acid production. (Reference 3).
19
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F. GAS SYSTEM DUCTWORK
The layout of the gas system ductwork is shown on Figure 2.
Roaster gases are collected and pass through a common flue to
four parallel electrostatic precipitators as shown in Figure 4.
An elevation drawing of the reverberatory furnace and roaster
precipitator flues is presented in Figure 5. The cleaned
roaster gases are discharged to a 544 foot stack. Fugitive
emissions from the roaster building are controlled by a pair of
baghouses in parallel. An old six chamber Cottrell precipitator,
currently being bypassed, can be used in emergency situations
to treat roaster gases. Reverberatory furnace gases pass
through waste heat boilers and travel through a common flue to
three parallel electrostatic precipitators. An elevation view
of the waste heat boiler downcomers and reverberatory furnace
flue is shown in Figure 6. The cleaned reverberatory furnace
gases are discharged to the 544 foot stack. The roaster and
reverberatory furnace gases enter at opposite sides of the stack.
Converter gases, collected in hoods, pass through a balloon flue
to four parallel electrostatic precipitators and are discharged
from a 564 foot stack. The converter precipitator inlet and
outlet ductwork is shown in Figure 7.
G. SULFUR BALANCE AND GAS COMPOSITION AT SYSTEM EXIT
Based upon reference 1, a typical dust and sulfur emission calcu-
lation is as follows:
Input Process Weight
Roaster and Reverberatory - 2,984 tons/day
Converter - 1,508 tons/day
Sulfur - 771 tons/day
20
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FIGURE 4
ROASTER DUST & GROUND SMOKE COLLECTION SYSTEM
(Located in pocket inside of back cover)
21
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.
O INDICATES EXPANSION JOINT NUMBER,
INDICATES ANCHOR OR FIXED POINTS.
I. WORK THIS DW6. WIT/-/ DW6.42-S-I5.
DOUGLAS REDUCTION WORKS
PL VERBERA TOR Y PRECIPITA TORS
ROASTER PRECIPITATORS i FLUES
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DOUGLAS REDUCTION WORKS
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REVISIONS
FOR
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REFERENCE DRAWINGS
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WASTE HEAT 30ILEH
SECTIONS C-C'
LOOKING "WEST AT
i C,-C,
*" 3 W.H. 'BOILER
PHELPS DODGE CORPORATION
COPPER OUEEN BRANCH- DOUGLAS, ARIZONA
'/16*. I'-O"
Stearns-jtoger
OKDO* N
3-36&00
D.R.
41-1-05
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23
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NU . ' \
. JS.YflfH
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1 t I- ,-.' ^V 7
DOUGLAS REDUCTION WORKS
d-d £6OMN6 W
PHELPS DODGE CORPORATION
COPPER QUEEN BRANCH-DOUGLAS,ARIZONA
FIGURE 7
gtearns-fioger
-------
Process Emissions
Roaster and Reverb dust - 39.0 tons/day
Converter dust - 1.1 tons/day
Sulfur Emissions
Roaster Dust - 4.9 tons/day
Roaster Gas - 345.0 tons/day
Roaster Ground Smoke - 7.8 tons/day
Reverberatory Furnace Dust - 3.4 tons/day
Reverberatory Furnace Gas - 97.4 tons/day
Reverberatory Furnace Ground Smoke - 1.0 tons/day
Converter Ground Smoke - 22.0 Ibs/day
Anode Gas - 0.3 tons/day
Total 727.5 tons/day
Table 1 is a summary of gas stream characteristics from Reference 4
showing SO- source, flow rate, concentration, particulate loading
and disposition of gas stream.
A single calcine charge, whose makeup is primarily dependent upon
inventory balances of smelter receipts is used for all the reverbera-
tory furnaces. Variations are usually gradual and surge capacity is
such that a relatively standard mix can be maintained over large
periods of time.
All materials bedded are assayed for SiO?, Al«0., Fe, CaO, MgO, S
and metal values. Bedding of the various materials follows the
current standard mix. Barren silica and lime rock are used for
fluxing.
The amount of sulfur left in the calcine following roasting is
dependent upon grade of copper in the bed mix and converter smelting
requirements. With the large amount of scrap materials and secondaries
being smelted, it is desirable to maintain a matte balance which will
keep the converters operating at near capacity. Sufficient sulfur
2 5
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GAS STREAM CHARACTERISTICS
OF
PHELPS DODGE CORPORATION
DOUGLAS COPPER SMELTER
SO, Source
Weak
Roaster
Reverb.
Conv.
Strong
Flow Rate
Scfm @
70° F 14. 7 Psi
250-265,000
145-156,000
210-265,000
Concentration
Percent
S00
1.0
1-2
2-4
SO
--
0.1
0.2
°2
15.2
5-7
12
Particulate
Treatment
Precipit.
Precipit.
Precipit.
Outlet
Loading
gr/AFC
.01 fir
.01 qr
.02 gr
Disposition of
Gas Stream
Emitted throuah stack
Temp. 305° F
Emitted through stack
n ii it
Temp. 340° F
Plant
Age
1903
Difficulty of
Retrofitting
Control
Extremely
Difficult
Remarks
Old plant
Installation of
Control facilities
would not be
feasible
Note: The plant generates its own power from waste heat steam and direct fired boilers. Water supply is limited. Highly variable
smelting charge characteristics.
Reference 4.
26
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content in the calcine is maintained to give the required matte
plus the excess required for reduction of magnetite in the
reverberatory furnaces.
The fluxing of each bed mix is dependent upon the calcine sulfur
to be obtained and upon the plant metallurgical balance. Silica
and lime are placed on the roaster beds to produce a final
reverberatory furnace slag with a silicate degree of 1.45 to 1.50
when the charge is roasted to the correct sulfur.
Converter flux usually contains over 68% SiCL which was determined
by experience to give satisfactory fluxing with a maximum use of
secondaries and reasonable refractory life. Converter slag generally
averages 23% Si02 with 30% Fe 0,.
Magnetite control is quite important at this smelter due to the long
furnace operating periods between major repairs. Magnetite buildup
in the reverberatory furnaces is controlled through adjustment of
calcine sulfur, charge fluxing and furnace heat.
The sulfur balance summary follows:
Input sulfur 771.1 TPD
Roaster 349.9 TPD (1.8% S0? bv)
Reverberatory furnaces 100.8 TPD (1.1% SO. bv)
Converter 245.7 TPD (1.8% S02 bv)
Slag and Tailings 22.0 TPD
Fugitive emissions 52.7 TPD
As can be seen, the percent S0? is quite low for both the converters
and the roasters. This can partially be explained by the fact that
the condition of the roasters is quite poor which results in
considerable air leakage. The excess dilution air results in
27
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converter and roaster offgas SO- concentrations below what would
normally be observed. The converters have hoods that are mounted
such as to result in a fairly large gap between the top of the
converter and the bottom of the hood, thereby allowing an excess
of dilution air to enter the converter gas system. In addition,
there are leaks in the existing ductwork. The condition of the
roasters is such that they cannot be repaired.
A typical gas composition leaving the roasters, reverberatory
furnaces, and converters follows:
Roaster Offgas 290,000 SCFM @ 1.7% S02
Reverberatory Furnace Offgas 150,000 SCFM @ 1.0% SO-
Total R & R Offgases 440,000 SCFM @ 1.46% SO.
Converter Offgas 125,000 SCFM @ 6% SO,
H. GAS CHARACTERISTIC VARIATIONS
As in all smelters using a reverberatory furnace, it can be expected
that the SO. concentration in the offgas will vary significantly with
time. This results from the variations in time required for
decomposition of reaction from the various sulfite ores charged to
the furnace. The SO- concentration has been known to vary as much
as 10 to 1 within a given charging time cycle. While no data are
yet available from this smelter concerning this point, it should
be considered for control system design.
The SO. concentration in the converter offgas will also vary
considerably because of the intermittent operation of the converters.
Generally, two slag blows and one copper blow will take place with
the converter being rolled out for slag pouring or material charging
between these blows. While an attempt is made to maintain at least
28
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one converter blowing at any given time, this does not always
occur. Usually, a converter will be provided with 18,000 to
20,000 SCFM to the tuyeres. An additional 100-120% dilution
air is generally estimated to be added to this gas flow resulting
in a total gas flow from each converter in the range of 35,000 to
40,000 SCFM. With the converter hoods gap being as large as it is
at this smelter, much larger quantities of air tend to be induced,
causing a reduction in the S0« concentration as well as loading the
flow system. With four converters operating, it would be expected
that no more than 160,000 SCFM would be observed in the converter
flue system. However, 210,000 to 265,000 SCFM occur, indicating
excess air leakage and dilution.
I. STACK DESCRIPTION
There are two main stacks at this smelter, one handling the roaster
and reverberatory furnace offgases and the other handling the converter
offgases.
Roaster and Reverberatory Furnace Stack
Height 544 feet
Diameter 22.65 feet Top (22.0 feet liner (I.D.)
Stack diameter at flue inlet 32.7 feet
Converter Stack
Height 564 feet
Diameter 19.0 feet Top.(18.0 feet liner I.D.)
Stack inside liner diameter at flue inlet 33.0 feet
29
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J. PRESENT TECHNIQUE FOR SOLID WASTE HANDLING
All dusts collected in the precipitators treating roaster,
reverberatory furnace, and converter gases are returned to
the roasters. Slag from the anode furnaces is returned to
the converters. Slag from the converters is transported to
the reverberatory furnaces. Reverberatory furnace slag is
hauled by electric car to the slag dump.
K. FOOTING AND STRUCTURAL REQUIREMENTS
No local codes apply. National Uniform Building Code is used.
Seismic zone 2, a wind load of 20 PSF, and a snow load of 10 PSF are
used for design. Ambient temperature is 20° F to 108° F.
L. EXISTING AND POTENTIALLY AVAILABLE UTILITIES
The power requirements for the smelter and a good share of the
power requirements of the Bisbee operations are produced by an
onsite power plant. Smelter operation requires both AC and DC
electricity and high and low pressure air.
The waste heat boilers produce steam at 350 psi and 660 F, which
is used in power generation by three 5,000 KW turbo-generators with
surface condensers, duplicate condensate pumps, and air ejectors.
The alternators are cooled with integral air coolers. Three pumps
circulate condenser cooling water through a cooling pond with a
surface area of 200,000 square feet. A direct-fired Erie boiler,
rated at 60,000 Ibs. steam/hr is located within the power house
for use in power generation when the waste heat boilers are unable
to meet the requirements.
30
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Boiler feed water is obtained from a preparation unit consisting
of multiple-effect evaporators operated by high-pressure steam.
Distilled water from the evaporators is stored in two tanks. The
feed water is deaerated, conditioned, and heated prior to use.
At times, steam production is in excess of power requirements, and
in such circumstances, the excess steam is condensed and the water
returned to the water system.
The plant DC requirements are generated by two 600 KW motor
generator fly wheel sets and two 300 KW motor generator sets.
Converter air is supplied by three 20,000 CFM electrically
driven turbo blowers and one 30,000 CFM steam turbine turbo blower.
Constant converter air pressure is maintained by an automatic
Askania controller.
With the exception of small compressors at the gas reformers,
100 psi high-pressure plant air is supplied by five electrically
driven air compressors at the power house.
Plant water supply is from three wells on the property. The ground
water is quite soft though high in total solids which are largely
sodium choloride and sodium sulfate.
Three 44,000-volt circuits are available for transmission of power
to the Bisbee operation.
M. POTENTIAL NEW CONTROL EQUIPMENT INSTALLATION AREAS AND PROBLEMS
There appears to be sufficient space adjacent to this smelter for
additional control equipment, although distance from the smelting
operation and structural interferences could increase cost and
operational problems. Water supply may be a problem if the control
system requires a large quantity of makeup water.
31
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REFERENCES
1. Emission Calculations - Douglas Smelter
Phelps Dodge Corporation - by Engineering Services Section
Division of Air Pollution Control - Arizona State Department
of Health 12-70.
2. "A Description of Plant and Operation" Phelps Dodge Corporation,
Douglas Reduction Works, Douglas, Arizona, October 2, 1971.
3. Extractive Metallurgy, Joseph Newton, Wiley, New York, 1959,
"Smelting Practices of Phelps Dodge in Arizona", M.G. Fowler.
4. Letter from John H. Davis, Jr., Chief Mechanical Engineer,
Western Engineering Department, Phelps Dodge Corporation,
February 12, 1975
32
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TECHNICAL REPORT'DATA
(Please read./Kttmctions on the reverse before completing)
1. REPORT NO.
EPA-6QO/2-76-036h
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
Design and Operating Parameters for Emission
Control Studies: Phelps Dodge, Douglas, Copper
Smelter
February 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHORIS)
8. PERFORMING ORGANIZATION REPORT NO.
I. J. Weisenberg and J. C..Serne
9. PERFORMING ORG 1.NIZATION NAME AND ADDRESS
Pacific Environmental Services, Inc.
1930 14th Street
Santa Monica, CA 90404
10. PROGRAM ELEMENT NO.
1AB013; ROAP 21ADC-061
11. CONTRACT/GRANT NO.
68-02-1405, Task 5
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park5 NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Task .Final; 4-10/75 '
14. SPONSORING AGENCY CODE
EPA-ORD
IS. SUPPLEMENTARY NOTES
EPA Task Officer for this report is R.Rovang, 919/549-8411, Ext 2557.
16. ABSTRACT
rep0rt gjyes background design data for a specific copper smelter.
The data is sufficiently detailed to allow air pollution control system engineering
studies to be conducted. These studies will be concerned primarily with lean SO2
streams that currently are not being captured. Physical layout of the smelter and
the surrounding area is presented, along with existing control equipment. Ductwork
that would be considered for future system tie-in is defined. Emissions from
operating equipment, gas flow rates, temperatures, sulfur balance, and a process
flowsheet are included. Utilities, stack dimensions, footing requirements', and
solid waste handling are defined. Available area for new control equipment, gas
characteristic variation, and potential new control equipment installation
problems are discussed.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Air Pollution
Copper
Smelters
Design
Sulfur Dioxide
Utilities
Air Pollution Control
Stationary Sources
Emission Control
Operating Data
Solid Waste Handling
Wastes
13 B
07B
11F
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (Tins Report)
Unclassified
21. NO. OF PAGES
36
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
33
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