Energy Requirements in Electrolytic Winning and Refining of Metals

CIM Bulletin, Vol. 70, No. 783, 1977

V. A. Ettel, Section Head, Electrochemistry, Inco Metais Company, J. Roy Gordon Research Laboratory, Mississauga, Ontario

Current practices in electrolytic winning and refining of copper, nickel and zinc are reviewed from the point of view of their respective energy requirements. The electrical energy requirements of these processes are broken down into the individual components, which belong to two basic categories: (a) thermodynamic energy requirements (AG of the desired reaction); (b) energy losses (anode and cathode polarizations, ohmic drops in the electrolyte and in the cell hardware, energy losses due to unwanted side reactions and electrical shorts). The individual energy components are separately examined for each electrolytic process and the potential for energy saving in these processes is discussed. It is shown that many potential energy-saving measures are uneconomical at the present time, as they increase over-all operating costs. The discussion is focused on those approaches which hold most promise for the future.

Keywords: Hydrometallurgy, Copper refining, Electrowinning, Nickel refining, Zinc refining, Thermodynamic energy, Cathodic over potential, Anodic over-potential, Electrolytes, Aluminum refining.