Beneficiating quartz-contg. oxide iron ore - by roasting with reductant and chlorine-source in closed furnace

摘要

The process comprises charging the ore, together with less than 15% (by wt. of ore) of a chlorine source and an excess (w.r.t. iron redn.) of a carbonaceous reductant, into a reaction vessel, indirectly heating the mixt. to max. 950 deg. C, and maintaining the reaction gases in intimate contact with the ore to produce an agglomerate of iron-free ore particles and reductant, bonded together by a matrix of intermeshed fine fibres of mainly metallic iron. Pref. the chlorine source is a metal chloride, and the reductant is coal, coke, charcoal or lignite used in amt. greater than 10% (by wt. of ore). The process is used for concentrating oxidic iron ores with a high quartz content, in which the iron mineral is finely dispersed in the gangue, e.g. Clear Hills ores, Maquette ores and Snake River ores. Chlorine, from the chlorine source, acts as a catalyst for transport of the iron mineral to the surface of theore particles where it is reduced to metallic iron. The resulting agglomerate is relatively easily concentrated, e.g. by magnetic separation, to give a high yield of high grade iron concentrate.