A study of the voltage and current efficiencies of fused salt AlCl3 electrolysis using bench scale cells

The fused salt electrolysis of AlCl₃ dissolved in LiCl-NaCl melts at 700°C was studied using bench scale cells employing graphite electrodes. The effects of AlCl₃ concentration, forced convection, interelectrode spacing, and current density on the voltage, current, and energy efficiencies of the process were investigated. At a practical cell voltage of 3.05 V and current density of 15 kA·m^?2 the electrical energy consumption per kg of aluminum produced by the AlCl₃ process was about 32 MJ, compared with a typical value of 52 MJ·kg^?1 for the Hall-Héroult electrolysis.