An Investigation into Pre-concentration of Low-Grade Silica-Rich Malanjkhand Copper Ore by Wilfley Table

Pre-concentration stages are generally employed to process base and precious metals where the feed grades are inferior. The pre-concentration could remove major gangue minerals and enrich the desired metal content. Further, it improves the efficiency of subsequent concentration stages. In the present investigation, pre-concentration studies were carried out on the mixed copper ore from Malanjkhand, India, containing 0.48% Cu and 74.12% SiO2 contents. Mineralogical characterization revealed that chalcopyrite is the major copper contributing mineral along with a minor amount of malachite. The major gangue minerals present in the ore are quartz, feldspar and mica. Liberation studies of the feed material indicate that around 75% of gangue minerals (mainly quartz) are liberated at 150 µm. Pre-concentration studies were carried out using a Wilfley shaking table, wherein deck angle and wash water rate were varied to achieve the maximum recovery and grade. Optimum results were achieved at a wash water rate of 3.5 lpm and deck angle of 4.9°, wherein the silica rejection and separation efficiency of 52.19% and 53.68% were achieved. The final product assays 2.79% Cu grade and 66.32% copper recovery. The investigation results indicate that the shaking table could be used to pre-concentrate Malanjkhand copper ore.