BLAST SMELTING METHOD Russian patent published in 2004 - IPC

FIELD: ferrous metallurgy, in particular, blast furnace smelting method.

SUBSTANCE: method involves charging burden into blast furnace, with burden comprising agglomerate and pellets, coke, fluxes, metal admixtures; controlling chemical composition of burden components and amounts; controlling amounts and composition of cast iron and slag at discharge end; determining alkalinity of slag from ratio: B=z·(15.446k2-3.873k+1.211)±c, where k is coefficient calculated as weighted mean of weight ratio of (SiO₂+Al₂O₃)/Fe_tot in mixture of ore materials of agglomerate burden and regulating said ratio within the range of 0.05-0.12 at the ratio of Al₂O₃/SiO₂ ≤ 0.20, domensionless; c ≤ 0.10; z is coefficient expressing influence of sulfur delivered into blast furnace in conjunction with burden onto slag alkalinity. Slag alkalinity is regulated by altering consumption of fluxes in burden, said fluxes including precalcined and live limes, dolomite, dolomitized lime, at weight ratio of components of MgO/CaO=0.15-0.30, with number of components being set by predetermined ratio.

EFFECT: improved quality of cast iron.

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