Industrial heap bioleaching of arsenic-bearing low-grade copper sulfide ore

Industrial heap bioleaching tests of 300 t Cu and 1000 t Cu per year were done for low-grade copper sulfide ore bearing arsenic from Zijinshan Copper Mine in Fujian Province,China.The results of the industrial tests indicate that the copper leaching rate increases with the decrease of ore grain size and the leaching rate of 80.58% is obtained during the leaching cycle of 270 d at the particle size of -30 mm.The copper extraction rate and electrowinning current efficiency reduce with the decrease in pH values of the pregnant leaching solution and the increase in mass concentration of iron ions in the electrowinning solution.The copper extraction rate declines to 50% when the pH value of the pregnant leaching solution fells to 1.19.After the innovation process,such as raise of heap height,periodical neutralisation of raffinate solution,load increase of organic phase scrubbing,and removing organic matter from the electrowinning original solution with activated carbon,sand filtration and air flotation column,the consumptions of extractant,kerosene and electrical energy drop and the copper leaching rate is enhanced.The copper leaching rate of 81.31% and the cost of RMB 10500 per ton high-purity cathode copper were gained during the leaching cycle of 200 d with the power consumption of 2 679.98 kW·h·t^-1.