Sulphurous acid as anodic depolarizer in copper electrowinning Part II

Abstract

The growing interest in the electrowinning of copper has lead to several modifications including anodic reactions proposed to reduce the high energy requirement. The addition of sulphurous acid to a copper sulphate electrolyte has been studied to avoid oxygen evolution at the anode which requires a potential in excess of 2 V. In particular, the effect of different anode materials, concentration of sulphurous acid, current density, copper and sulphuric acid concentrations in the electrolyte have been investigated. Measurements of anode potential, cell voltage, current efficiency and energy consumption during the electrowinning of copper have been made using a diaphragm cell. It was found that graphite and lead coated with Ir-O-2 are better electrode materials than lead and DSA anodes and sulphurous acid can be used as anodic depolarizer.