Cell voltage in aluminum electrolysis: A practical approach

During aluminum electrolysis there must be an optimum cell voltage for a given cell design at constant amperage. This optimum-voltage target depends on the goal, which may change with economic conditions. Although cell voltages have been reduced steadily during the last 50 years, they now seem to have reached a constant level at 4.1 V to 4.2 V, at least for cells larger than 200 kA. Efforts to reduce cell voltage will continue to show incremental improvements; however, it will be difficult to achieve major voltage reductions without a drained cathode combined with inert sidewalls to permit increased thermal insulation. Warren Haupin is retired from Alcoa. For more information, contact H. Kvande, Hydro Aluminium Metal Products, N-0246, Oslo, Norway; telephone 47-22-73-91-55; fax 47-22-73-77-78; e-mail Halvor.Kvande@hydro.com.