Study of Copper Leaching Technology from Copper Ores by Biochemical Method

The article presents the research results on the processing of dump ores of copper production from one of the deposits of Kazakhstan. The copper content in various rock formation samples and from different sampling points varies from 0.2 to 0.9%. On average, the calculated copper content on the southern side of the dump was 0.3%, and on the northern side, 0.28%. Phase analysis of the dump samples revealed that the bulk of the rock is represented by quartz, albite, muscovite, clinochlorite, and noticeable amounts of malachite and atacamite were noted from copper dumps in many areas. Detailed mineralogical analysis, in addition to oxidized forms of minerals, also recorded fragments of sulfide mineral formations such as pyrite, chalcopyrite, chalcosine, etc. For this type of deposit, the most effective method of processing will be the use of biohydrometallurgical heap leaching technology. According to percolation leaching, the use of trichloroisocyanuric acid (TСCА) as a chemical oxidant was considered, and an adapted culture of A.Ferrooxidans was also used as a biooxidant. According to percolation leaching, the use of trichloroisocyanuric acid (TСCА) as a chemical oxidant was considered, and an adapted culture of A.Ferrooxidans was also used as a biooxidant. Standard sulfuric acid leaching served as a control option. As a result of the application of the chemical oxidation method using TСCА, an increase in copper extraction into solution compared with other options was observed only during the first 7 cycles. The highest efficiency was observed in the variant of preliminary bacterial oxidation, 76.08% copper was extracted into the productive solution over 28 irrigation cycles. The resulting productive solutions of all variants were subjected to a full technological cycle of hydrometallurgical copper production. As a result of the extraction and re-extraction processes, electrolyte solutions were developed that fully correspond to the qualitative parameters necessary for electrolysis. At the electrolysis stage, 30.8 g of copper was deposited on the cathode from the accumulated electrolyte solutions, which gives a current recovery equal to 94.6%.