Energy consumption of aluminium smelting cells containing solid wetted cathodes

Tests with 10 kA pilot cells show that substituting a wetted, dimensionally stable cathode for the turbulent metal cathode allows the anode-cathode distance (ACD) to be decreased, with an attendant voltage reduction of about 1 V, depending on current density. Since high current efficiency is retained, specific energy consumption is decreased by about 20%. These savings are not as great as anticipated, however, because the effective electrical resistivity of the electrolyte increases as the ACD is lowered. This effect is ascribed to an increased void fraction of anode gas in the interpolar space, which appears to be dependent on anode size.