was approximately minus 6 plus 16 to minus 12 plus 30 mesh although other convenient sizes used in industrial adsorption processess can be used the carbon particles were packed to provide an intimate contact individually and to the anode cylinder this requirement however does not appear to be too critical because well packed carbon columns used to adsorb precious metals can also be used as the anode assembly after the adsorption step the electrolyte was comprised of an equal volume mixture of 0 5n sodium hydroxide and 0 1n sodium cyanide although electrolyte of other combinations can also be used if the alkalinity is maintained as required by equation 1 electrolysis was conducted at temperatures of 40 u00b0 and 86 u00b0 c however temperature apparently had no effect on the deposition of the precious metals furthermore it was found that the voltage and current are not critical so long as they are sufficient to maintain a good mass transfer from the anode to the electrolyte and a good formation of precious metal deposits on the cathode in the cell used in the examples set forth below the cathode and anode distance was approximately 3 4 inch apart however other distances can be employed to obtain the best mass transfer in the electrolytic reactions stirring was not found to be important because good mixing of the electrolyte was provided by the generation of anodic oxygen the aforementioned condenser was necessary to prevent the loss of water through evaporation especially when the electrolysis was conducted at a temperature of greater than 50 u00b0 c activated carbon suitable for use in the present invention is a widely available material that is conventionally used in adsorption processes including precious metal adsorption it may be.