GB818236A - Method and apparatus for reduction of metal oxides - Google Patents

Abstract

818,236. Reducing iron and other metallic oxides. TAYLOR, C. A. May 18, 1956 [June 1, 1955], No. 15651/56. Classes 72 and 82(1) [Also in Group XII] 4 A method of continuously reducing metallic oxides to metals comprises feeding particles of oxide of size 100 to 500 mesh to a vertical reaction zone for free gravitation at descent while free hydrogen passes upwardly in contact with the particles, maintaining a temperature gradient increasing downwardly of the reaction zone from the reaction temperature to a temperature not exceeding the sintering temperature of the metal particles, adding selectively hydrogen, oxygen, or combustion air, or cooling gas to the reaction zone at a plurality of levels, and removing the metal through a cooling zone from the lower end of the reaction zone. As shown, applied to the reduction of iron ore, the ore is "supplied, preferably preheated, to a feed mechanism 2, to which free hydrogen may be added, and discharged to the top of a shaft 1 lined with refractory material and having constrictions 5 dividing it into zones A, B, C and D. Each zone is provided with gas inlets, preferably in the form of three rings each having a plurality of nozzles, those in the outer two rings being horizontal and those in the centre inclined upwardly, for the addition as required, of hydrogen, oxygen or combustion air, or a cooling gas, e.g. nitrogen, the amount of each gas being so controlled that the temperatures in the zones A, B and C are, zone C-250 to 300‹C., zone B-300 to 600‹C. and zone A-850 to 1000‹C. The iron produced in zone A falls through a restriction 5 into zone D where it is cooled by a gas at 15‹C and finally removed from the shaft to storage or to a melting furnace. The gases fed to the shaft are controlled by thermostats and control gear and the waste gases, part of which may be removed from the bottom of the furnace, may be recycled through a regenerating system.