METHOD OF PREPARING LITHIUM-CONTAINING FLUORIDE SALTS FOR ELECTROLYTIC ALUMINUM PRODUCTION Russian patent published in 2002 - IPC

FIELD: nonferrous metallurgy. SUBSTANCE: invention, in particular, relates to those salts that can be used as complex additives in molten salt electrolysis-mediated production of aluminum and involves mixing - and fluoride-containing components. The former is lithium chloride solution obtained by selective sorption of lithium from naturally-occurring brine on inorganic sorbent. Sorbent is washed to remove brine, after which lithium chloride is desorbed by water. The latter operation is continued until residual content of brine in sorbent bed attains a value ensuring percentage of lithium chloride in desorbed phase with respect to the total chloride content therein to be 50 to 86%. Desorbed phase is concentrated to concentration of LiCl 40-50 kg/cu.m and then, for 40-60 min, solution containing stoichiometrically required amount of fluoride-containing reagent is added to precipitate lithium, calcium, and magnesium fluorides. Resulting sludge containing insoluble fluorides is thickened during 60 to 90 min, chloride- containing mother liqueur is discarded and resulting precipitate is dehydrated and dried on heating. As fluoride- containing reagent, sodium fluoride is used. EFFECT: enhanced process efficiency due to reduced cost price pf lithium- containing raw material. 3 cl, 1 dwg, 1 tbl