Experimental method for direct electrorefining of both copper and copper alloy scrap

The electrorefining of primary copper is a well known technology: in this work copper scrap was directly processed in the same way. The copper and copper alloy scrap was previously pressed by means of a 20 tons apparatus in order to avoid pyrometallurgical operations. The samples obtained in this manner showed a good compactness so that they were used as anodes in the electrorefining tests. The tests were carried out on anodes made by copper scrap, copper alloy scrap and a mixture of the two. The electrorefining tests were performed at both 303 and 333 K, in a perspex cell having a volume of 500 ml using a current density of 250 A/m(2). The cathode used was always a sheet of pure copper and the electrolyte composition was 40-50 g/l Cu as CuSO4 and 150-200 g/l H2SO4. Current efficiency in the range of 92-97% and specific energy consumption ranging from 0.14-0.20 kWh/kg of copper were reached in all the tests. The refined copper deposits were analyzed by AAS to verify their purity and observed by SEM to highlight their morphology.