Development of flotation technology for processing refractory gold-bearing ores from the Aktobe deposit

The quest for cost-effective methods to process gold-bearing ores is inextricably linked to a series of preliminary studies, including ore composition analysis, evaluation of the occurrence forms of valuable components, and assessment of the impact of impurity elements and ore physical characteristics on gold recovery. Flotation remains a cornerstone technology in the gold mining industry, essential for the beneficiation of gold-bearing ores. Central to this process is the selection of flotation reagents, which enable effective separation of gold from gangue and associated minerals. This study focuses on the flotation of previously unexamined low-sulfide gold-bearing ore from the Aktobe deposit in the Republic of Kazakhstan. Mineralogical and X-ray phase analyses identified quartz, potassium feldspar, calcite, mica, limonite, and sulfides as the principal minerals in the ore. Phase analysis further revealed that 46.47 % of the gold occurs as free cyanidable gold in open intergrowths, while 37.61 % is locked within sulfides, and 15.92% is finely disseminated in waste rock. To optimize the flotation process, the influence of critical parameters such as grinding size, reagent dosages, flotation time, and flotation machine type on gold recovery was systematically investigated. Closed-circuit tests with one and two cleaner flotation stages were performed using the optimized reagent regime. The results have demonstrated that a single cleaner flotation stage achieved a 1.14 % higher gold recovery, reaching 89.84 %. The concentrate obtained after the cleaner flotation contained 23.01 g/t of gold, making it suitable for subsequent hydrometallurgical processing.This research was funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (grant No. AP19680182).