Effect of Grinding Fineness on Concentrate Grade and Metal Recovery in Copper-molybdenum Ore Beneficiation

This study examines the influence of grinding fineness on concentrate grade, product yield, and copper, molybdenum, and gold recovery during flotation beneficiation of copper-molybdenum ore from the Kalmakyr deposit. Five grinding conditions were compared, corresponding to 57%, 60%, 65%, 70%, and 80% by mass passing 0.074 mm. The evaluation was based on the reported assays, yields, and recoveries of flotation products under the investigated flowsheet. Increasing the proportion of material passing 0.074 mm from 57% to 70% raised copper recovery from 83.79% to 88.73%. At 70% passing 0.074 mm, the combined concentrate yield was 7.76%, with grades of 3.82% Cu, 0.039% Mo, and 5.02 g/t Au; corresponding recoveries were 88.73% Cu, 82.61% Mo, and 77.80% Au. At 80% passing 0.074 mm, copper, molybdenum, and gold recoveries increased further to 89.01%, 83.14%, and 79.67%, respectively, while the combined concentrate yield was 7.72%. Thus, the finer grinding condition delivered the highest reported recoveries, whereas the 70% condition provided a slightly coarser alternative with recoveries close to those obtained at 80%. Without grinding-energy or operating-cost measurements, an economic optimum cannot be demonstrated from these data alone. The manuscript also discusses staged addition of spindle oil, regrinding, and the possible inclusion of centrifugal gravity concentration. These process modifications are distinguished from the grinding-fineness comparison and should not be interpreted as verified improvements without matched experimental controls. The findings provide an experimental basis for comparing practical grinding targets for the investigated ore and identify the additional measurements required before final process optimization.