Aluminum production by carbothermo-chlorination reduction of alumina in vacuum

Aluminum production by carbothermo-chlorination reduction of alumina in vacuum was investigated by XRD, SEM, EDS and thermodynamic analysis. Thermodynamic calculations indicate that AlCl（g） generated by carbothermo-chlorination process among Al2O3-C-AlCl3 system should be at 1377-1 900K （100 Pa） and AlCl（g） will disproportionate into aluminum and AlCl3（g） below 950-1 050 K at 10-102 Pa. Experimental results demonstrate that Al4O4C and Al4C3 begin to be formed by Al2O3-C system over 1698 K （40-150Pa）. It is Al4O4C and Al4C3 but not Al2O3-C that participate in the carbothermic-chlorination reaction. Temperature for AlCl（g） generated by Al4O4C-AlCl3-C, Al4C3-Al2O3-AlCl3 and Al4OC-Al4C3-Al2O3-AlCl3-C system is 1 703-1853 K （40-150 Pa）. Aluminum metal is produced by AlCl（g） disproportionation process below 933 K. The average purity of aluminum metal reaches 95.32%, which has perfect crystallization and uniform grain size.