METHOD OF DESULFIRIZATION OF PIG IRON AND CHARGE FOR PRODUCTION OF SLAG DESULFURIZER Russian patent published in 1997 - IPC

FIELD: ferrous metallurgy, particular, desulfurization of liquid pig iron with slag desulfurizers; compositions of slag desulfurizers. SUBSTANCE: pig iron is treated with slag desulfurizer with basicity of 0.90-1.45 and sulfur content of 0.002-0.200% with total consumption of 1.5-4.5% of pig iron mass in two stages. During the first stage, pig iron is treated with slag desulfurizer of fraction +3.0-80.0 mm, which is supplied to ladle bottom and/or stream of pig iron in the amount of 30-80% of the total consumption. At the second stage, pig iron is treated with slag desulfurizer of fraction +0.2-3.0 mm which is supplied in jet of carrier gas inside the melt in the amount of 20-70% of the total consumption. Slag desulfurizer is produced from mixture containing 2.8% of sodium carbonate, 5-15% of lime and desulfurized blast-furnace slag. Mixture may additionally contain slag of production of secondary aluminium in the amount of 5-25%. Slag desulfurizer may be used in form of desulfurized blast- furnace slag. EFFECT: higher efficiency. 5 cl, 2 tbl