COPPER RECOVERY AND CYANIDE DESTRUCTION WITH A PLATING BARREL CATHODEAND A PACKED-BED ANODE

A batch electrochemical cell, consisting of a plating barrel cathode a nd a packed-bed anode, was used to recover copper from a waste acid co pper sulfate solution and simultaneously to recover copper and destroy cyanide in a waste copper cyanide solution. The cyanide destruction e xperiments were carried out with and without the addition of NaCl. The concentrations of total cyanide, free cyanide and copper were measure d as a function of electrolysis time at various solution temperatures, cell currents, barrel rotation speeds, barrel loadings, and barrel im mersion levels. The total cyanide concentration was reduced from 580 p pm to less than 10 ppm. The average energy consumption was 80 to 340 k Wh/kg of total cyanide destroyed, depending upon the operating conditi ons. A cost analysis indicates that the present electrolytic method is more cost effective than the conventional alkaline chlorination treat ment for waste cyanide solutions. It also offers a cost advantage over a commercial carbon fiber electrolytic process because of a lower cap ital investment.