Chlorination reaction of alumina coated with carbon by thermocatalytic cracking

Abstract

For the production of aluminum chloride, chlorination behaviors of sandy alumina coated with pyrolytic carbon have been examined by changing the amount of carbon coated, coating temperature, and specific surface area of alumina etc. The experimental results obtained are summarized as follows:
(1) The chlorination reaction of alumina was affected by the characteristic of carbon pyrolytically coated and the crystallization of γ-alumina.
(2) The chlorination reaction rate of alumina having the specific surface area of 100-200 m²/g was faster than that of 10-100 m²/g.
(3) For the complete recovery of aluminum chloride at 600°C, it was required to deposit carbon of about 17.2wt% on alumina by thermocatalytic cracking. At temperature of 500°C600°C, the carbon consumption increased by 5wt% as the temperature increased by 25°C.
(4) For the effective utilization of chlorine, the bed height of sample in chlorination reactor had to be adjusted by considering the chlorination temperature.
(5) Chlorination reaction of alumina coated with pyrolytic carbon was accelerated by the addition of a small amount of NaCl or KCl. However, the chlorination reaction was decreased when these salts were excessively added because the contact of chlorine with alumina particle was prevented by NaAlCl₄ or KAlCl₄ formed.