Propagation of Solid-Phase Iron Reduction in a Layer of Ilmenite Concentrate

Abstract

Processing of titanium-containing ores together with the extraction of all the major elements is currently an urgent problem for the usage of mineral products. It is shown that none of the existing processing schemes allows the simultaneous extraction of all the major useful elements such as iron, titanium and vanadium from titanium-containing iron ores. This problem can be solved using a selective extraction of these elements based on ideas regarding the electron reduction mechanism. The following has been experimentally studied: the reaction propagation of solid-phase selective iron reduction that is deep in the grain layer of ilmenite concentrate from the surface of its contact with the powder of carbon-containing material. The results are presented for determining the amount of released metal phase depending on the distance from the concentrate–reducing agent contact boundary. Based on the results regarding the amount of the released metal phase, a conclusion was made for the diffusion processes in a layer of concentrate grains that contact only between themselves, thus determining the rate of iron reduction process. It is shown that near the contact surface between the solid reducing agent and the layer of concentrate grains, the rate of iron reduction is higher than the formation rate of the phases with high iron content from ilmenite. Deep in the ilmenite concentrate layer, the process of iron reduction is preceded by the formation of an iron-containing silicate phase from the concentrate grains, where iron is reduced earlier than it is in the ilmenite grains. The formation of iron-containing silicate phase promotes ilmenite grains to be sintered. Thus, upon the concentrate layer contacting with solid reducing agent in the absence of contact between each ilmenite grain and solid reducing agent, the point contact between grains and void presence within the layer do not prevent the reduction process propagation in the grain layer that contact only with each other.