Study of the feasibility of hydrometallurgical processing of oxidized copper ores of the Kalmakyr deposit

Uzbekistan holds substantial reserves of oxidized and mixed copper ores at the Kalmakyr deposit, exceeding 120 million tons, with plans for future development at the Dalneye deposit, which also contains these ore types in its upper layers. This paper provides an analysis of global practices in processing oxidized copper ores. Currently, the most advanced technology for producing cathode copper is solvent extraction and electrowinning (SX-EW), which accounts for 16–17 % of global copper production. This process involves heap leaching of low-grade, off-balance oxidized copper ores, followed by solvent extraction and electrowinning. The study focuses on technological samples of oxidized and mixed copper ores from the Kalmakyr deposit. The mineral composition of these ores was analyzed, revealing the presence of copper minerals such as chalcopyrite, chalcocite, covellite, malachite, and azurite, with micaceous minerals posing a challenge to ore enrichment. Associated minerals include apatite, rutile, zircon, sphene, epidote, and zoisite. Industrial tests, including both heap and vat leaching with sulfuric acid solutions, were conducted. Key variables such as sulfuric acid concentration, ore particle size, process duration, temperature, and the solid-to-liquid (S : L) ratio were adjusted in the experiments. Under optimal conditions, copper recovery reached 65.9 % with heap leaching and 80 % with vat leaching. Based on these findings, the agitation vat leaching method is recommended due to its significant advantages over other hydrometallurgical techniques, particularly for processing refractory ores.