GB1213641A - Production of iron, steel and ferrous alloys - Google Patents

Abstract

1,213,641. Reducing iron ores. BRITISH IRON & STEEL RESEARCH ASSOCIATION. Jan. 4, 1968 [Jan.4, 1967], No.518/67. Heading C7D. Iron, steel or ferrous alloy is manufactured by, in a first stage, injecting a first hydrocarbon, e.g. through tuyeres 25 fed via line 1, and an O2 - containing gas, e.g. through lances 27 and tuyeres (26, Fig. 2) fed via line 3 into and/or over a molten iron bath 28, e.g. in a stationary, tilted or rotated converter or shaft kiln, to crack the first hydrocarbon to produce an H2-containing gas and reduce any iron oxides e.g. wustite to molten iron, passing the H2- containing gas, e.g. through a hollow trunnion 22 of the converter, in countercurrent to iron ore e.g. haematite in a second stage, e.g. in a shaft kiln, fluidized bed-containing vessel or rotary kiln 13 to reduce the ore at least partially, the reduced ore e.g. sponge iron/ wustite bed 10 being fed to the first stage, injecting a second hydrocarbon (the same or different from the first) e.g. from pipe 2 into the second stage to quench the H2 - containing gas stream passing therethrough so that incipient fusion of the ore is inhibited and its pore structure maintained, and tapping off molten iron 28 and slag 29 from the first stage. Effluent gas from the second stage drawn from offtake nipple 17 may be recycled to the first stage and burnt with the first hydrocarbon via line 6 to burner 5 and/or introduced into the second stage with the second hydrocarbon to provide the quenching stream, preferably after passing through a dust cyclone and water washer 14, and tubular heater 8, e.g. to heat the quenching stream to 225-725‹C. Either hydrocarbon may be gaseous, liquid or solid, or mixture thereof, e.g. methane, butane and/or naphtha. The carbon (smoke) simultaneously formed by the cracking dissolves in the molten bath to be burnt-off with the O2- containing gas injected. An electric furnace may be incorporated in the first stage to supplement the heat requirements. The ore, charged through feed hopper 15, may be initially beneficiated by magnetic separation, and comprise partially reduced ore and/or iron scrap, carbonaceous material such as coke or coal and/or a flux; the latter may be fed to the first stage into the molten iron, Specification 1, 187, 781 is referred to.