Method for reducing material containing iron oxides

Abstract

A method of reducing a pulverized material containing iron oxides mixed with carbonaceous material wherein: (a) a circulating fluidized bed is maintained in a vertically elongated reaction zone by supplying it with suitable quantities of pulverized material containing iron oxides, pulverized solid carbonaceous material and optionally liquid carbonaceous material, and gas containing molecular oxygen and that gas and solid material leaving the reaction zone are separated, the solid material being returned to the reaction zone; (b) the pulverized material containing iron oxides, the carbonaceous material and the gas containing molecular oxygen are supplied to an intermediate section of the reaction zone; (c) the flow of carbonaceous material fed to the bed is controlled so that there is always sufficient coke in the bed to prevent interference of the fluidization caused by sticking or agglomeration; (d) gas and solid material leaving the reaction zone are extracted from the upper part of the reaction zone, the solid material being separated from the gas and being returned to the intermediate section of the reaction zone; (e) a portion of the gaseous reaction zone exhaust, after dust separation and elimination of most of carbon dioxide and water, is fed to the lower part of the reaction zone as fluidizing and reduction gas; and (f) solid material containing completely or partially reduced iron oxides is drawn from the lower part of the reaction zone.