GB919681A - Improvements in or relating to the reduction of iron oxide - Google Patents

Abstract

Iron oxide is reduced to a lower state of oxidation at a temperature between 750 DEG C. and incipient fusion in the presence of excess carbon and a dolomite or limestone flux, by carbon monoxide generated in situ by partial combustion of the carbon: an auxiliary fuel with the requisite oxygen is fed to maintain a uniform temperature in the reduction zone. The iron oxide is at least 3 mm. in size and may have been pelletted and subjected to an oxidizing roast to remove sulphur. The carbon, e.g. anthracite, has a particle size of 12 mm. or less and the flux, present in at least 4% of the charge, has a particle size of 1 to 3 mm. Reduction is preferably effected in a rotary kiln, the charge being fed countercurrent to the burning auxiliary fuel which may be fed in axially as well as at spaced intervals along the kiln, in the form of oil or gas, for example town gas. The reduced ore is preferably passed through a rotary cooler countercurrent to town gas which is then fed to the output end of the rotary kiln. The reduced ore may be coated with graphite or lime, or both to prevent oxidation.ALSO:Iron oxide is reduced, so that 85-95% of the iron content is metallic, at temperatures between 750 DEG C. and incipient fusion in the presence of excess carbon and a dolomite or limestone flux, by carbon monoxide generated in situ by partial combustion of the carbon; an auxiliary fuel with the requisite oxygen is fed to maintain a uniform temperature in the reduction zone. The iron oxide is at least 3 mm. in size and may have been pelletted and subjected to an oxidizing roast to remove sulphur. The carbon, e.g. anthracite, has a particle size of 12 mm. or less and the flux, present in at least 4% of the charge, has a particle size of 1-3 mm. Reduction is preferably effected in a rotary kiln, the charge being fed countercurrent to the burning auxiliary fuel, which may be fed axially as well as at spaced intervals along the kiln, in the form of oil or gas, for example town gas. The reduced ore is preferably passed through a rotary cooler countercurrent to town gas which is then fed to the output end of the rotary kiln. The pellets of reduced ore may be fed to an iron or steel making furnace.