METHOD OF PREPARING PURIFIED LITHIUM ALUMINUM CHLORIDE

Purified lithium aluminum chloride (LiAlCl4) is prepared by passing hydrogen chloride gas through a melt of lithium aluminum chloride containing impurities such as water, hydroxides or other inorganic oxygen-containing salts, carbon and iron, to remove at least a portion of the water and oxygen-containing impurities. Thereafter, the melt is heated to a temperature of from about 425 DEG to about 540 DEG C. and chlorine gas is passed through the melt to remove carbon impurities. The melt is cooled to about 190 DEG C. to 260 DEG C. and contacted with aluminum to replace the iron in solution because of its higher electrochemical potential. The purified melt is filtered and cooled. Analysis of a typical product shows less than 300 parts per billion of impurities. The starting lithium aluminum chloride may advantageously be prepared by melting admixture of reagent grade lithium chloride and reagent grade aluminum chloride. Mixture of lithium aluminum chloride and aluminum chloride can be prepared using an excess of reagent grade aluminum chloride reactant.