TREATMENT OF COPPER CYANIDE WASTEWATERS IN ELECTROCHEMICAL BATCH REACTOR WITH STAINLESS STEEL ELECTRODES

Much attention has been paid to the study of the electrochemical oxidation of cyanide in metal electrowining and mining industry from metal cyanide solutions. Galvanostatic batch electrolyses of strong alkaline copper cyanide wastewaters have been carried out in an undivided cell using stainless steel plates as electrodes at different current densities as a function of electrolysis time. The influence of these variables on cell voltage, energy consumption, chemical oxygen demand (COD) reduction, removal efficiency of copper and cyanide was reported. At current density of 10 mA cm(-2) for 90 min of treatment, cyanide and copper removal efficiency was 87.2 and 89.1%, respectively, and COD reduction was 81.5% at pH 13 and 25 degrees C. Complete removal of copper is achieved during the 100 min of electrolysis at the above-mentioned conditions. Experimental data show that it is possible to perform efficient oxidation of cyanide and simultaneous regeneration of copper in the form of pure deposits on the cathode and reduce COD using electrochemical batch reactor with stainless steel electrodes.