Processing Hard Coal Mining Wastes of the Luhansk Region as Man-Made Metal Deposits

Abstract

Coal mining waste rock dumps contain a lot of rare and precious microelements and are a single complex mechanism of the chemical and biochemical transformations of substances, and the key role in such transformations belongs to sulfuric acid formed as a result of the vital functions of thionic bacteria Th. Ferrooxidans. The aim of the present work was to develop an environmentally friendly biotechnology for processing coal mining waste rock dumps of the Luhansk Region as man-made metal deposits. The spectral analysis of the waste rocks of the Luhansk Region revealed high concentrations of precious, rare-earth, and trace elements. A high prevalence of gallium and germanium clarkes was found, and their actual concentration in the waste was close to the minimum industrial concentration. The results of chemical analysis of the waste rock for Al₂O₃ showed that its concentration was close to that in poor bauxites, a traditional raw material for alumina. A method and technology of the biochemical leaching of aluminum, gallium, and germanium, which make use of the natural processes of sulfuric acid formation in waste rock were proposed, and their efficiency was experimentally confirmed. The proposed biochemical technology for the processing of coal mining waste rocks can serve as the basic method for diminishing their environmental impact and rational use of natural resources.