The processing of a Fe-containing anolyte produced by a copper electro winning process carried out in a reactive electro dialysis (RED) cell has been studied. The resulting anolyte was an acidic aqueous solution which contained FeIII species. This solution can be used: (a) as a leaching agent or (b) as a source of commercially valuable ferric sulfate. Two operations were studied in this work: (i) leaching of metallic copper and (ii) crystallization of iron sulfates. In both cases, the kinetics, optimum operating conditions, mass balance and efficiency were determined. As a result, two conceptual flow diagrams for copper electro winning-anolyte processing were proposed to help the development of new hydrometallurgical processes. (C) 2007 Elsevier Ltd. All rights reserved.