Leaching kinetic of copper oxide ore containing carbonate gangue in the acid condition

This article is focused on the leaching kinetic of copper oxide ore containing carbonate gangue.The effects of temperature,acid concentration,particle size,liquid-to-solid ratio and stirring rate on leaching of the copper oxide ore were determined.The results show that high temperature,high acid concentration,high liquid-to-solid ratio,low particle size and high stirring rate benefit the copper leaching.However,the carbonate gangue leads to a high consumption of acid.In consideration of leaching cost,the proper leaching condition is the temperature of 303 K,acid concentration of 35 g·L^-1,particle size of 0.074-0.125 mm,liquid-to-solid ratio of 3:1,and stirring rate of 180 r·min^-1.After leaching for 180 min,the copper leaching rate reaches 53.6%.The morphologies of the ore surface before and after leaching were investigated and the results reveal that the carbonate gangue dissolves in the acid solution and CaSO₄·2H₂O precipitation forms on the ore surface,which limits the development of porosity and cracks.Based on the shrinking core model,the leaching kinetic was analyzed.It is found that the precipitation on the ore surface hinders the leaching reaction.The diffusion across the product layer is the rate-controlling step and the activation energy is determined to be 8.65 kJ·mol^-1.