Application of a biconical dense medium cyclone to pre-treat a low-grade Pb-Zn sulfide ore

A biconical dense medium cyclone (BDMC) was applied to reject the gangue from a low-grade Pb-Zn sulfide ore for the first time. Based on mineralogy and heavy liquid separation tests, it was found that the rejection of gangue by the BDMC prior to grinding and flotation was promising. The results revealed that the particle size clearly affected the heavy liquid separation process. The effects of several parameters, such as medium specific gravity (SG), spigot diameter, tilt angle, cone angle and medium/ore mass ratio, on the yield of floats and on the metal recoveries in the floats were examined and the optimal parameters were determined. The results showed that 51.22% of floats were obtained with a lead recovery of 7.92% and a zinc recovery of 12.50%. The extended tests were further carried out with the BDMC being capable of throughputs about 3 t/h, which verified the results obtained in the laboratory experiments. The use of this equipment to pre-treat the refractory ore is promising.