Removal of alkali metals and alkaline earth metals from molten aluminium

Abstract From the Canadian patent

For removing contaminant alkali- and alkaline earth metal contaminants, particularly Li, a particulate aluminium fluoride-containing material is introduced into a vortex established in a non-cylindrical body of molten aluminium contained in a vessel. The generation of the vortex establishes currents having both downward and lateral components at the bottom of the vortex and upwardly spiralling currents at the periphery of the vessel, which serve to recirculate suspended matter. The stirring of the molten metal is continued until the contaminant level is reduced to a desired level and then the molten Al is separated from the reaction products. The body of metal is contained in a vessel which …