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EPA
TECHNOLOGY
TRANSFER
us
ENVIRONMENTAL
POI 11 ITI^K i PROTECTION
-POLLUTION AGFNCY
ABATEMENT INDUSTRIAL
^A DEMONSTRATION
COPPER GRANT WITH
WIRE VOLCO BRASS &
COPPER COMPANY
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EPA
TECHNOLOGY
TRANSFER
POLLUTION
ABATEMENT
COPPER
WIRE
MILL
US.
ENVIRONMENTAL
PROTECTION
AGENCY
INDUSTRIAL
DEMONSTRATION
GRANT WITH
VOLCO BRASS &
OOPPEROOMPANY
REGIONS LIBRARY
U. S. ENVIRONMNTAL PROTECTION
AGENCY
1445 ROSS AVENUE
DALLAS, TfWS 75?Q?
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Fine wire following peroxide bright pickling
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All wire drawing operations require cleaning
of the metal surfaces before drawing to
prevent surface impurities from being pulled
into the drawn wire. This cleaning or
"pickling" is usually accomplished by the
use of sulfuric or hydrochloric acid. To maintain
good pickling activity the solution must be
replaced when it reaches a minimum
concentration. This depleted pickling solution
is then a waste disposal problem.
The metal must also be washed free of
pickling solution. The resulting rinse waters
contain metal salts. Because of the low
concentration of these contaminants the
rinses are difficult to treat economically.
In the case of the production of copper
wire, additional complications are present
because of the chemical reduction of cupric
oxide to a cuprous oxide coating which
cannot be removed by sulfuric acid. This
coating has normally been treated by a
"secondary pickle" of chromic acid-sulfuric
acid, chromic acid-ammonium bifluoride
mixtures, or by nitric acid. All of these techniques
produce additional pollutants. Each of the
3 to 4 drawing steps required to produce
fine copper wire from copper rod requires
these pickling and rinse steps.
The waste from such an operation, if treated
by conventional precipitation techniques
without an examination of the manufacturing
process itself, would impose a severe cost
on the manufacturing operation and produce
large amounts of sludge for disposal.
In this EPA demonstration grant, the
Volco Brass and Copper Company, of
Kenilworth, New Jersey, with Lancy
Laboratories as consultants, demonstrated
that water consumption could be reduced by
90% from 200,000 gallons per day to 20,000
gallons per day by chemical rinsing and water
reuse. The sulfuric acid pickle was regenerated
and high purity metallic copper recovered by
continuous electrolysis, thereby eliminating
the dumping of spent pickle liquor. Hydrogen
peroxide was proven to be an improved
secondary pickle and the chromates and
fluorides previously used were eliminated.
Total solids leaving the plant in the rinse
waters were reduced from 2500 Ibs/day to
less than 100 Ibs/day. Metal losses in the
effluent were reduced to less than one pound
per day compared to the previous 600-700
pounds per day.
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I FROM DEIONIZER |"
mm mm ymummum •
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The pollution control system which is
integrated into the manufacturing process
consists of three basic steps:
1. The regeneration and copper recovery
system for the primary pickle bath
2. The chemical rinse system
3. The use of hydrogen peroxide plus
proprietary additives for the secondary
pickle.
Figure 1 illustrates the final process with
each section highlighted by separate color.
The top block ("A") shows the work flow
through the new system. After the hot sulfuric
acid pickle and the secondary pickle of 2.5%
hydrogen peroxide in sulfuric acid, the work
passes through a chemical rinse step which
neutralizes the acid drag out. It also precipitates
any copper salts by reduction of cupric (Cu"1"4")
ions to cuprous (Cu+) ions which are insoluble
at the pH of the chemical rinse. The work
then goes to a cold rinse using city water,
a hot rinse using deionized water, and finally
a lubricant bath prior to the drawing operation.
The portion of the flow diagram enclosed
as Block "B" shows the electrolytic copper
recovery cell, which recovers metallic copper
and regenerates sulfuric acid from the metal
salts in the hot sulfuric acid pickle solution. It
was originally felt that the trace metals (zinc,
tin, lead) would interfere with the recovery of
pure copper. By controlling current density
at five to ten amperes per square foot,
however, pure copper can be recovered while
maintaining the copper concentration in the
pickle bath at fifteen grams per liter.
The secondary pickle reservoir is also shown
in Block "B". Copper sulfate accumulates in
this bath and eventually crystallizes out. These
crystals can be recovered and sold as a copper
rich sludge or added to the electrolytic copper
recovery loop.
The chemical rinse reservoir is maintained
at the proper pH and composition by the
addition of caustic, sodium carbonate, and a
reducing agent, in this case hydrazine. The
sludge draw off along with the flow from the
floor spill neutralization first goes to a sludge
filter to recover salvage copper sludge and
then to a final sump for discharge.
The rinse flows go to a pH adjustment tank,
a settling tank and finally to the rinse water
sump where the bulk of the flow is recirculated
to the first water rinse tank.
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Heavy wire drawing
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PjREWOUS EFFLUENT WS, THE NEW AT VOLCO KENILWORTH
75 TPD of Finished Wire
(Pickled 3-4 Times to obtain Final Product)
Ibs/ton finished wire
unless otherwise noted
Water Usage
pH
Total Cr.
Zn
Cu
Suspended Solids
Dissolved Solids
OLD
24000 (150 GPM)
3.8
2.2 (90 ppm)
4.8 (200 ppm)
2.4 (100 ppm)
.7 (30 ppm)
36 (1500 ppm)
NEW
1600 (10 GPM)
7.5-8.5
0
.002(1 ppm)
.002 (1 ppm)
.03 (20 ppm)
1.3 (800 ppm)
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gTS
$3.60/h
Sendees
hr.
Sanitary Sewer Charges 150 CPM
$ 1,500
14,00)
Gal
Sludge Haulage @ 8C/Gal
III. Maintenance, 3% of Inv.
IV. Labomtoiy 2 hr/day
@'$3.60/hr
V. Overhead @ 125% of
Qper. & Main. Labor
VL Raw Materials
Primary Pickle Chemicals
Bright Pickle Chemicals
Treatment Chemicals
TOT£L Materials
TOTAL Operating Costs
F»ed Charges
Depreciation @ 15 yrs,
Ta&es^ Insurance @ 5%oflnvest
TOTAL Rxed Charges
Credife
Copper at 5G£/R>,
.
Reducs^l 0le Maintenance
14,000
14,000
6,300
1,900
8,000
8,100
16,100
53,800
—
__
53JW)
14,000
6,300
18,000
1,800
32,300
8400
32,000
48,100
156,100
4QtOQO
_
.199,100
900
4,200
1,800
10,400
36,000
13,000
49,000
74,100
9,300
700
, 10,000
(10,000)
( 8,000)
130,000)
36400
TofesI annual cxlatsof pcftittoa abatement Astern unth&ut credit for
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Peroxide bright pickle reservoir tank (left). Floor spill
The economics for this project are presented
in comparison to the previous operating
situation with essentially no waste treatment,
and to estimated costs if a conventional
precipitation and neutralization waste
treatment system had been installed without
modifying the manufacturing process itself.
The approach taken for this project gave a
major reduction in pollutants, including
sludge, at a.slight profit, while the isolated
installation of a waste treatment system
would have resulted in a major cost to the
company.
neutralization tank (right).
Several changes were made in the plant
operation simultaneously with the installation
of the pollution abatement system resulting in
a total of $100,000 annual savings cost in
the drawing operation. The credit of $30,000
annually for increased die life taken for this
project is an estimate by the Volco staff.
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•y Electrolytic Copper
S Recovery Cell
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Intermediate wire following peroxide bright pickling
This process is currently being used at five
other installations manufacturing copper and
copper-alloy products. The chemical rinse
technique is applicable to electroplating
operations and has gained wide acceptance
there. Any facility utilizing a fluoride-chromate
bright pickle should consider the use of a
hydrogen peroxide-sulfuric acid mixture as an
alternative to treatment.
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For further
information:
Detailed information
on this project,
is available from
the Superintendent of
Documents as
EPA Report 12010 DPF
"Brass Wire Mill
Process Changes and
Waste Abatement,
Recovery and Reuse"
Or write:
Technology Transfer
Environmental
Protection Agency
Washington, D.C.
20460
U.S. GOVERNMENT PRINTING OFFICE. 1973 0-727-913
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