The electrolysis of Al2S3 in AlCl3-MgCl2-NaCl-KCl melts

Energy consumption of the Hall--Heroult, Alcoa AlCl3 and Al2S3 processes are, respectively, 14.1 and (projected) 9.9, 7.0 kWhr /kg. Experimental results for Al2S3 dissolved in MgCl2--NaCl--KCl eutectic containing 10% AlCl3 at 1023 deg K show that it can be electrolyzed into Al and elemental sulfur. It appears that within the range 0.2-1.2 A/cm exp 2 the cathode current efficiency of the electrolysis of 5% Al2S3 does not vary significantly with the current density. Within that current density range current efficiencies of approx 75-85% were obtained. 20 ref.--EAA/AF.