REMCO ENGINEERING ENVIRONMENTAL WATER SYSTEMS AND CONTROLS
REMCO ENGINEERING
ENVIRONMENTAL WATER SYSTEMS AND CONTROLS
METALWINNING SYSTEMS
Remco Engineering manufactures three types
of electrowinning systems, parallel plate, high surface area and
barrel. Each has its special niche that makes it very cost
effective in its special applications. Parallel plate systems
recover very large amounts of metal in very little space. The
maintenance is higher on parallel plate systems, you have to
strip plates but for high volume recovery in minimal space, these
are the champs. The high surface area cell are great for reducing
metals to discharge limits. There efficiency is very high.
Maintenance is reasonable and for systems up to 20 lb/day, they
are cost effective. The barrel systems are very efficient, low
maintenance systems were the product is easily handled. Each
barrel can handle 100-150 amps so multiple barrels are used as
the plating requirements increase. The cost trade offs are about
equal. The parallel plate units use a lot of expensive anodes but
the barrels and required hoist and support systems for the
barrels are also expensive. The high surface area cell are the
most efficient in using the anode surface are and are therefore
the lowest cost system.
DESCRIPTION - Remco Engineering metalwinning systems remove
metals, cyanides, and other organics from electrolytic solutions.
These larger units (see the P-SET literature for small
in-the-tank units) feature very large surface areas in a small
space. Using anode and cathode materials suitable to the
solution, the system features low current density with high
surface flow rates. The low current densities allow good deposits
at low concentrations. High flow rates create turbulent flow
which minimizes the diffusion layer and results in increased
efficiencies.
Barrel systems are unique in that the product is easily handled
and readily recycled. The operation of the barrel results in and
nonadhearent metal being removed immediately so the result is
solid metal balls which are easily recycled. There are no sheets
to strip as with a parallel plate system. There are no very
expensive pads to buy as with a flow through cell. The plating
media is BB size shot and this is built up to about 1/2" in
diameter. The barrel is easily emptied into a tray which drops
the media into a small bucket. "BB's" are placed back
into the barrel and the processes is started again.
While not designed specifically as final treatment before
discharge, parallel plate units can be fitted with high surface
area reticular pads for plating solutions to very low
concentrations. When used with a metal recovery ion exchange
system, regenerant solutions are plated to about 200-400 ppm.
Because the solution is used to elute the resin column and
recover more of the metal, the residual concentration is not very
important. Used as a batch plateout unit with ion exchange, the
parallel plate unit can run to about 150 ppm before efficiency
begins to degrade past the point of usefulness. Adding high
surface area reticulated cell allows metal to be plated down to
about 1-2 ppm but the efficiency is low once metal content is
under 50 ppm.
Our systems feature our all fiberglass skid and superstructure as
found on our ion exchange systems. All controls, recirculation
tanks, plumbing, rectifiers and pumps are mounted on one easily
installed skid. The systems plating cell is a tank within a tank.
The plating cell has a sealed bottom to catch any sludge and is
easily removed from the recirculation tank for cleaning. Each
unit is completely wired, plumbed, and shipped ready to run.
Barrel units have a superstructure and hoist for lifting the
barrel and holding it up so the barrel can be dumped easily.
SIZING -
PARALLEL PLATE SYSTEMS are sized in increments of cathode surface
square feet. Two sizes of standard cell exists, one containing 64
surface square feet of cathode area fits a 36" tank and the
other containing 88 surface square feet of cathode area fits a
48" tank. Current density should be kept as low as
practically possible for maximum efficiency. The lower the
current density (amps/sq. ft.), the easier it is to plate a good
deposit (good adhesion, no burning). When sizing a unit, add
30-50% to theoretical rectifier size for the decrease in
efficiency when plating under 125 meq/l (0.8g/l Cu). You don't
need the extra amperage to plate at low current densities, you
need it to plate faster at the higher metal levels so you have
more time to plate at low metal levels.
BARRELWINNING SYSTEMS are sized by barrel capacity. The standard
system will hold two 12" by 24" barrels with a capacity
of about 6-9 pounds of copper for each barrel (100-150 amps). The
standard tank is 36" by 48" which holds two barrel
modules. Multiple systems are used for higher capacities.
EXAMPLE - For an ion exchange system metal recovery unit required
to recover 40 pounds of copper per regeneration with 3 days
between regenerations -
1. From the electrochemical equivalent table, Copper deposits 4.2
oz/100 amp hours at 100% efficiency. 40 lbs X 16 oz/lb = 640 oz.
2. 3 days X 24 hours = 72 hours.
3. 640 oz / 72 hours = 8.88 ounces/hr.
4. 8.88 / 4.2 ounces per 100 amp hrs = 2.11 (100 amp-hrs) or 211
amps
5. 211 * 1.3 (efficiency loss and margin) = 274 amps
6. Round up to 300 amp rectifier (minimum, for the small cost
difference, 500 amp would be best.)
ELECTROCHEMICAL EQUIVALENTS
Metal Symbol Oz/100 amp hrs Grams/100 amp hrs Cadmium Cd 7.4 209.7 Cobalt Co 3.9 109.9 Copper(2) Cu 4.2 118.6 Gold(troy,+3) Au 7.9 244.9 Lead Pb 13.6 386.5 Nickel Ni 3.9 109.5 Palladium Pd 6.4 198.5 Platinum Pt 5.8 181.9 Silver Ag 12.9 402.4 Zinc Zn 4.3 121.9
