GB441429A - Process and apparatus for the reduction of fine iron ores - Google Patents

Abstract

441,429. Metallurgical furnaces. WINTERSHALL AKT.-GES., 139, Hohenzollernstr., Cassel, Germany. Dec. 10, 1934, Nos. 35487, 35488, and 35489. Convention dates, Dec. 12, 1933, July 23, 1934, and July 23, 1934. [Classes 51 (i) and 51 (ii)] In the reduction of pulverized iron ores to iron powder in a rotary furnace, the reaction temperature is obtained by partial combustion of the reducing gases with pure oxygen, the escaping gases being treated for the removal of combustion products and returned to the furnace together with the requisite quantity of fresh gases. The reduction gases employed are preferably substantially free from hydrocarbons and may consist, for example, of water gas or cracked coke oven gas. As shown, a compressor g sucks the gases escaping at e from the furnace b through a cooler f and forces them, at a pressure of from 5 to 30 atmospheres, through a carbon dioxide washing tower h; the gases thus freed from carbon dioxide and steam, after reheating in the tubes of the cooler f and passage through a pressurereducing device l, are returned through pipe m to the discharge end of the furnace, the necessary fresh gases being added at o. The oxygen for combustion is delivered through a series of inclined nozzles v, Fig. 2, extending from pipes u through apertures d in the furnace shell, the supply being so controlled that oxygen is discharged only through those nozzles disposed in the upper half of the furnace. This control is effected by a device comprising rotary and fixed parts w, z, the former having cells communicating with the pipes u and the latter being fitted with an obturating flange in its lower half. When a mixture of carbon monoxide and hydrogen is used for the reduction, the process may be modified by converting the carbon monoxide to carbon dioxide and washing out the latter before the gas is supplied to the furnace ; in this case, the gas actually entering the furnace consists of substantially pure hydrogen and steam only has to be removed from the escaping gases before their re-delivery to the furnace.