Electrowinning of Copper in the Presence of Anodic Depolarisers - A Review

Abstract

Alternative anodic reactions have been investigated to reduce the cell voltage and hence energy consumption in the electrowinning of copper. It is necessary to avoid oxygen evolution reaction at the anode, which requires a high potential of 2 V in order to reduce the cell voltage. An extensive literature review reveals that the cell voltage can be reduced by using various ionic couples, such as Fe²⁺/Fe³⁺, Cu²⁺/Cu¹⁺. Addition of cobalt, soluble sulfites and sulfur dioxide to the electrolyte modifies the anodic reaction. Examination of several electrode materials for anodic oxidation confirms that graphite is the most suitable material. Some fundamental studies on the anodic oxidation of sulfur dioxide have also been reviewed.