Physical and chemical studies of finely-dispersed slurry tailings of the Donskoy Ore Mining and Processing Plant (DMPP) for chemical beneficiation to produce chromium concentrate

Abstract

During the processing of chromium ores, chromite concentrate is obtained for the production of ferrochrome, and waste is also collected - tailings beneficiation. Fragment and sludge tailings depending on the beneficiation technology. Finely dispersed sludge tailings of the Donskoy MPP of Kazchrome JSC are stored at the Dubersay and Akzhar tailings, which are man-made deposits (MMD) or man-made mineral formations (MMF). To develop a technology for processing sludge tailings, which contain up to 30% chromium oxide, their physical and chemical studies were carried out. According to the chemical analysis of sludge tailings, it follows that research should be directed to the removal of magnesium and silicon oxides, thereby increasing the content of chromium oxide to a standard chromium concentrate. A very thin dissemination of chromite with minerals of host rocks necessitates additional grinding of intermediate products, which are intergrowths of chromite with waste rock. According to the results of fractional analysis and IR spectroscopy, the content of a large number of flocculants in the studied sludge tailings and a large number of particles with a particle size of less than 20 μm, which, in heavy liquid solutions, due to its small size, is in suspension and does not stratify, was revealed. According to the granulometric composition, it was determined that the sludge minus 0.071 mm must also be classified into 0.04 and 0.02 mm and enriched each class separately. It has been established that in order to obtain high technological performance, the traditional gravitational beneficiation scheme used at the DMPP is technologically cumbersome, because includes operations of flocculant disintegration, classification, grinding, beneficiation on concentration tables of each size class, regrinding of intermediate products. The results of the physicochemical study of chromium sludge tailings showed the need for a combined beneficiation scheme, including chemical enrichment with finishing of chromium concentrate by gravity beneficiation.