Effect of mechanical activation on thiosulfate leaching of gold from complex sulfide concentrate

The use of mechanical activation to enhance gold recovery from a CuPbZn complex sulfide concentrate was investigated. The effects of milling time, ball size, sample to ball ratio and milling speed on thiosulfate leaching were studied. Under optimum conditions of milling time 1 h, ball size 20 mm, sample to ball ratio 1/15 and mill speed 600 r/min, nearly 78% of sample is amorphized, particle size decreases from d(100)=30 mu m to d(100)=8 mu m, specific surface area increases from 1.3 m(2)/g to 4.6 m(2)/g and gold recovery enhances from 17.4 % in non-activated sample to 73.26 %.