METHOD OF PRODUCING ALUMINIUM OF THE SPECIAL PURITY Russian patent published in 1995 - IPC

FIELD: nonferrous metallurgy. SUBSTANCE: aluminium of special purity is produced by by-stage decrease of impurity of different classes. Purification from alkaline and earth-alkaline metals is carried out by aluminium stirring with flux consisting of fluoride and/or chloride salts at concentration 0.1-0.3% of aluminium mass, at 680-800 C, at mixer number revolution 400-800 rev/min. Then boron-containing compounds or master alloy were added to aluminium at concentrations that 1.5-3 times exceed of required by stoichiometry, at 680-800 C, at stirring at the angle rate 400-800 rev/min to remove peritectic impurities. Fractional crystallization is carried out on the cooling body rotating at the angle rate 500-2000 rev/min. EFFECT: improved method of aluminium production. 3 tbl