PARALLEL PLATE METALWINNING SYSTEMS

DESCRIPTION - Remco Engineering metalwinning systems remove metals and cyanides 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.

While not designed specifically as final treatment before discharge, they can be fitted with high surface area reticular pads for plating solutions to very low concentrations. When used with an 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.

SIZING - 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 rectifer 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

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. 40lbs 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