A method for PURIFYING a Molten Mass com - Light Metal aluminum or other metal contaminated with Cerium Rare Earth

摘要

A method of purifying aluminum contaminated with cerium or other rare earth metal comprises bringing the molten metal into contact with a halogenating agent. Preferred halogenating agents are aluminum 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 aluminum fluoride may be introduced into the vortex of a stirred body of the molten metal. The controlled addition of chlorine may be effected 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 aluminum reduction cell.