Study on the mineral processing technology of low-grade refractory leadzinc oxide ores containing argillaceous and carbonated gangue in Yunnan

Both sandstone and limestone ores, investigated in this paper, are two types of low-grade complex lead-zinc oxide ores from Yunnan province, China. Because of higher acid consumption (H2SO4 250 kg/t for sandstone ore and 450 kg/t for limestone ore) and lower efficiency of liquid-solid separation, the process to handle these two types of ores has been a challenge. Although wet metallurgy can be considered, the high cost and low revenue limit this technology to be put into practice in large-scale. In order to solve this problem, a new technology combining mineral processing method with metallurgy technique is studied, which is used to process this refractory ore that consists of sandstone ore with 5.84 per cent Zn, 0.95 per cent Pb and limestone ore with 6.50 per cent Zn, 0.92 per cent Pb. The results of flotation closed-circuit tests showed that zinc and lead can effectively be recovered from two types of the ores by using the reasonable process flowsheet of flotation technology, and high-efficiency regulators and collectors simultaneously. For sandstone sample, totally 82.48 per cent Zn and 41.19 per cent Pb were recovered from the feed material. For limestone sample, 84.45 per cent Zn and 40.16 per cent Pb were recovered from the feed material. One merit of this process flow sheet is that the zinc and lead sulfides and oxides can be recovered in the flotation cells at the different stage and make sure the concentrate products as a good feed for hydrometallurgical technology. This study provided pretty good technical support for tapping low-grade refractory lead-zinc oxide ores.