METHOD FOR RECOVERING WASTES OF ALUMINUM ELECTROLYTIC REFINING PROCESS Russian patent published in 2004 - IPC

FIELD: nonferrous metal-working industry; recovery of anodic residue in aluminum electrolytic refining. SUBSTANCE: proposed method includes charging and melting of anodic residue, electrolysis and separation of solid and liquid phases; molten residue is heated to 900 - 920 C and subjected to electrolysis in fluoride melt incorporating BaF₂40-45 mass percent, the rest being NaF and AlF₃; cryolite ratio is 1.2 - 1.5 at 960 - 980 C, current density is 0.75 - 0.9 A/sq. cm, back emf is 1.1 - 1.2 V, and pole-to-pole distance is 5 - 8 cm, the result being cathodic and anodic products. Cathodic product is aluminum alloy incorporating 1 to 10 mass percent of silicon. Anodic product is copper alloy incorporating 7 to 15 mass percent of aluminum and 2 to 5 mass percent of iron. FeSi and Fe₃Si₂ base solid phase formed in the process that incorporates iron and silicon compounds is removed through electrolyzer pocket in amount of 2 to 5 kg per 1 t of anodic residue in high-purity aluminum production. Such process enables increase in current yield by 8% and reduction in secondary anodic residue by 95 kg per 1 t of anodic residue in high-purity aluminum production. EFFECT: enhanced current yield and reduced amount of secondary anodic residue formed in the process. 4 cl, 2 tbl