Method and apparatus for reducing iron-oxides-particles having a broad range of sizes

Abstract

Methods and apparatus for the reduction into metallic iron of iron-oxides-containing particles having a broad range of sizes. Particles, typically within a broad range of sizes of about 0.1 mm to about 50 mm, are reduced by contact with a hot reducing gas, preferably from a horizontal gas distributor which defines the bottom of the reduction zone by supplying a uniform upflow of gas mainly composed of hydrogen (and/or carbon monoxide) within a temperature range of 650° C. to 1050° C. and at a velocity of about 0.5-0.7 m/s to fluidize at least some of the particles of a size of about 1.0 mm or less (when present). The reducing gas flows upwardly through a descending moving bed of coarser particles and forms thereabove a fluidized bed of fines, all in a single chamber in a reduction reactor, where the particles charged to the reactor are fed into the fluidized bed, preferably at the lower portion thereof at or near the interface with the moving bed, and the lighter reduced fluidized fines are withdrawn from the reactor from the upper portion of the fluidized bed. The spent reducing gas from the reactor passes through at least one cyclone separator with the fines entrained therein being normally returned to the reactor or optionally being subjected to a lower velocity fluidization in a separate reduction chamber of the reactor.