Abstract
The improper selection of collector type and dosage without considering particle size distribution is a major issue in sulfide mineral flotation. Most studies focus on a single particle size, neglecting potential efficiency improvements with alternative collectors. This research examines the impact of apolar collectors on the selective flotation of copper-molybdenum ore from the Kalmakyr deposit in Uzbekistan.Flotation tests were conducted with two particle sizes, four pH levels, and varying blowing agent concentrations. Results indicate that coarser particles (71 μm) achieved higher copper (84.7%) and molybdenum (70.7%) recoveries than finer particles (44 μm), which yielded 71.6% and 68.5%, respectively. The optimal pH was 11, with a frother concentration of 60 g/t Oxal T-92. Among the tested apolar reagents – kerosene, spindle oil, and transformer oil – the latter provided the highest extraction efficiency.The study confirms a significant relationship between flotation parameters, emphasizing the need to optimize flotation conditions before full-scale application. These findings can aid in improving the flotation efficiency of Kalmakyr deposit ores and similar sulfide deposits.To maintain comparability, all experiments used the same conditioning time, pulp density, and air rate, so the observed trends reflect the effects of size, pH, and collector identity. Mechanistically, the 71 μm fraction showed higher bubble – particle collision efficiency and lower detachment, outweighing any liberation gains for fine particles in this ore. Alkaline conditions at pH 11 promoted selective gangue depression and more persistent hydrophilization of chalcopyrite and molybdenite. Under the optimized regime, transformer oil yielded the most robust Cu-Mo selectivity among apolar reagents, while excessive frother increased water recovery and entrainment of fines. The results support reagent screening before scale-up and provide a reproducible workflow for sulfide circuits.