FIELD: metallurgy.
SUBSTANCE: method involves melting of rejects in the furnace in inert atmosphere in presence of sodium tetraborate and boric anhydride at melting temperature or higher than melting temperature of aluminium; at that, at the beginning of the process the sodium borate is loaded to the furnace on the basis of 10-15% of the aluminium rejects mass expected to be loaded, boric acid the weight of which is calculated by the formula: m"нзвоз" = 0.0246 · mreject · X (1), where m"нзвоз" - weight of boric acid, which is loaded to the furnace, kg; mreject - weight of aluminium rejects loaded to the furnace, kg; X - content of aluminium oxide in aluminium reject, wt %; then, aluminium reject is loaded to the furnace on the basis that molten aluminium shall achieve the height of 800-1000 mm and exposed in the furnace during 45 minutes at temperature of 880-900°C. After exposure of molten aluminium in the furnace the temperature is decreased to 680-700°C and at this temperature the molten aluminium is drained to casting forms, first through the top taphole located at the height of 100 mm from the furnace melting pot bottom, then through lower taphole located on the level of the furnace melting pot bottom. Furnace has gas dead-end burners arranged in the chambers interconnected with the furnace melting pot by means of openings in the melting pot brickwork, and two tapholes.
EFFECT: invention allows obtaining high-quality aluminium from aluminium rejects, and reducing capital and operating costs.
4 cl, 1 dwg, 1 tbl
