Distribution of solid-phase reduction of iron in a layer of ilmenite concentrate

Abstract

Processing of titanium-containing ores with extraction of all the major elements is an urgent task of minerals rational use. It is shown that none of the existing processing schemes allows extracting of all the major useful elements at the same time from titanium-containing iron ores, i.e. – iron, titanium and vanadium. This problem can be solved using selective extraction of these elements based on new ideas about electronic reduction mechanism. Propagation of the process of solid-phase selective reduction of iron with the powder of carbon-containing material deep into the layer of grains of ilmenite concentrate from the surface of its contact was experimentally studied. The results of determining the amount of metal phase released as it moves away from the concentrate – reducing agent contact boundary are presented. Based on the results concerning amount of precipitated metal phase, a conclusion was made about diffusion processes in a layer of concentrate grains contacting only between themselves, limiting process of iron reduction. It is shown that near the plane of contact of solid reducing agent with the layer of concentrate grains, the rate of iron reduction is higher than the rate of high iron content phase precipitation from ilmenite. In depth of ilmenite concentrate layer, process of iron reduction is preceded by formation of iron-containing silicate phase from concentrate grains, where iron is reduced earlier than in ilmenite grains. Formation of iron-containing silicate phase contributes ilmenite grains sintering. It was concluded that in the concentrate layer in contact with solid reducing agent layer in absence of contact of each ilmenite grain with solid reducing agent, the point contact of grains and presence of voids between them in the layer do not prevent propagation of reduction process in the layer of grains contacting with each other only.