METHOD OF PROCESSING ZINC WASTES Russian patent published in 2000 - IPC

FIELD: non-ferrous metallurgy; processing zinc wastes in form of dross after zinc plating of iron and oxidized wastes. SUBSTANCE: wastes are charged into melt of equimolar mixture of sodium and potassium chloride at addition of sodium or aluminum fluorides at temperature of 740 to 790 C and after 15 to 30 minutes metallic zinc is extracted. Operation is repeated for 3 to 5 times, then 5 to 15 % of aluminum (of mass of melt of salts) is added and alumo-zinc alloy is extracted; sediment of oxides and intermetallic compound of iron with aluminum and zinc is extracted, after which operation is repeated. NaF or AlF₃ in the amount of 10 to 15% of mass of equimolar mixture of sodium and potassium chlorides is added as fluorides; single charge of zinc wastes is equal to 0.12 to 0.20 of mass of salt melt. Process is performed in one unit possessing high capacity; zinc is extracted not only from intermetallic compound but from zinc wastes. EFFECT: enhanced efficiency; increased productivity. 4 cl, 1 tbl, 3 ex