Method of purifying aluminium.

摘要

A method of purifying aluminium contaminated with cerium or other rare earth metal comprises bringing the molten metal into contact with a halogenating agent. Preferred halogenating agents are aluminium fluoride for reducing cerium levels to around 0.1 % to 0.3%, and chlorine gas for reducing cerium levels still further, and these may advantageously be used in sequence. Particulate aluminium fluoride may be introduced into the vortex of a stirred body of the molten metal. The controlled addition of chlorine may be affected by bubbling a mixture of chlorine and an inert gas into a body of the molten metal. The cerium contamination may arise from the use of a dimensionally stable anode comprising cerium dioxide in an aluminium reduction cell.