Regrinding and floc-flotation of silver sulphide scavenger concentrate

Abstract

In flotation circuits, scavenger concentrates are usually treated by recirculation to rougher flotation cells. This treatment is not effective on the scavenger concentrates in which valuable minerals are associated with gangue minerals in the form of fine dispersion. A regrinding and floc-flotation process was studied for the treatment of Fresnillo silver sulphide scavenger concentrate, to increase the silver grade and recovery of the final concentrate in the flotation circuit. The experimental results have shown that the process is very effective in treating the scavenger concentrate, producing a concentrate assaying 33 kg/t Ag with 80% recovery, in comparison with the 6 kg/t Ag and 70% recovery achieved by conventional flotation. Clearly, the substitution of regrinding and floc-flotation for simple recirculation in the flotation circuit will confer economic benefit. It has also been found that dispersion can improve the flotation of the silver sulphide mineral fines.