CONTINUOUS ELECTROLYTIC TREATMENT OF COMPLEX METAL CYANIDES WITH A ROTATING BARREL PLATER AS THE CATHODE AND A PACKED-BED AS THE ANODE

A continuous electrolytic process consisting of a plating barrel catho de and a packed-bed anode was used to recover metals and to destroy cy anide in waste silver, copper and cadmium cyanide solutions. The exper iments were carried out with and without the addition of NaCl to the f eed solutions. The effluent concentrations of total cyanide, free cyan ide and metal ions were examined for various cell currents, solution t emperatures, solution feed rates, solution recirculation rates, barrel rotation speeds, and barrel loadings. The total cyanide concentration was reduced from 520 ppm to fewer than 10 ppm, and metal concentratio ns from 225-486 ppm to less than 1 ppm. The average energy consumption per kilogram of total cyanide destroyed was: 80 to 490 kWh for silver cyanide, 80 to 520 kWh for copper cyanide, and 50 to 330 kWh for cadm ium cyanide.