| 摘要 |
Metal oxide is directly reduced by progressively deeper mixing of a coal layer, a metal oxide/coal mixture layer and an overlying preheated metal oxide layer on a rotary hearth to cause progressive homogenization and reduction of the charge. A metal oxide direct reduction process comprises (a) applying a preferably high volatile matter content coal layer onto the hearth of a rotary hearth furnace; (b) covering the layer with a slightly preheated metal oxide/coal mixture layer and an overlying metal oxide layer preheated to 800 degrees C for immediate start of metal oxide reduction by forced passage of released volatile components (especially hydrogen); and (c) mixing the layers at progressively deeper levels while the hearth rotates to cause homogenization and progressive reduction of the charge. Independent claims are also included for the following: (i) an installation comprising a rotary hearth furnace which includes equipment for progressively mixing overlying layers, the equipment being in the form of tines of rakes which penetrate the layers in a first fixed rake furnace zone and which are arranged radially in the furnace such that successive tines are disposed at progressively increasing depths as the material advances by hearth rotation; and (ii) metal sponge produced by the above process and/or in the above installation, the metal sponge having a better reduction uniformity than that produced by prior art processes and being produced in a short reduction time. |
