Abstract
The productivity of copper electrorefining cells can be significantly increased if the applied current density is increased. Pulsating currents (PC) or periodic current reversal (PCR) allow a three-fold increase in the normal current density used in refining plants. The productivity of the cell is increased and a satisfactory quality of cathodic deposit can be maintained. Laboratory-scale tests with PC and PCR techniques were performed with current efficiencies of 100% and 85%, respectively. In both cases the cathode quality was quite satisfactory. The microstructure and surface morphology of the deposits are illustrated. The presence of impurity cations, such as Fe, Zn and Sn, is shown to have only a limited effect on the quality of the cathode. It is concluded that, in general, the PC technique is more suitable than PCR for the electrorefining of copper.