Studies on the application of copper(I)-ammune sulphate electrolytes in copper electrorefining

Abstract

The electrolysis of a copper(I)-ammine sulphate electrolyte between copper electrodes has been investigated. A sealed cell and a solution containing 30 g/kg Cu, 95 g/kg NH 3 and 95 g/kg SO 4 were used. Current efficiencies (cathodic and anodic), at current densities over 100 A/m 2, were higher than 95% and were practically independent of the electrolysis variables (25–55°, 100–500 A/m 2 and 70–130 g/kg of NH 3 solution). It was shown that at temperatures over 40°C the energy consumption for electrorefining is lower in the copper(I)-ammine electrolyte than in a typical acidic electrolyte. Contributions to the energy consumption from the electrode processes and the resistance of the electrolyte have been determined from the experimental data.