Preparation of Superconcentrate and Chromium Powder from Chromite Ore

Abstract

Non-traditional metallurgical technology of comprehensive processing of Sevan chromite (with a 43–46% Cr₂O₃ content) is developed allowing chromium extraction from local chromite in the form of more expensive chromium powder. The process of increasing the reactivity of chromite concentrate (with a Cr₂O₃ content of 53%) as a result of thermal and mechanochemical treatment both in the presence and in the absence of chlorides has been investigated for this purpose. It is found that in both cases, with heating and with grinding in the presence of chlorides, selective chlorination occurs similar to high-temperature chlorination. The resultant iron and magnesium chlorides are removed after washing, and the remaining residue after drying is a super-concentrate with a Cr₂O₃ content of 74.12% in the case of firing and 77.23% in the case of mechanochemical activation, with a low iron and magnesium content. The possibility of obtaining powder chromium with low content of iron and magnesium by processing the super-concentrate obtained by extra-furnace aluminothermic reduction is demonstrated.