Recovery of a low-grade refractory copper sulfide ore by flotation in Dongchuan, Yunnan province

A certain copper ore in Dongchuan, Yunnan province, with the copper content of only 0.65%, the distribution rate of secondary copper sulfide reaching as high as 85.6% and the copper oxidation rate of 9.6%, having the high content of pyrite which could lead to a difficulty in copper-sulfur separation, containing some easily-sliming gangue minerals, belongs to the low-grade refractory copper sulfide ore. Flotation recovery study based on the ore’s properties shows that, grinding fineness is more appropriate to be chose as 80%-74um, Na₂S, at the mount 600g/t, has the better multi-function including precipitation, dispersion and activation, PAC should be chose as collector with optimal amount of 120g/t when CaO is chose as pH regulator and depressant of copper-sulfur separation, meanwhile, Na₂SiO₃is used as depressant and dispersant. Finally, by adopting the closed-circuit flowsheet of “one roughing - two cleaning - two scavenging”, the better technical index that copper grade and recovery of the final concentrate can reach up to 20.12% and 90.39% respectively, was obtained under the optimum condition.