Investigation to Determine the Performance of Acid Leaching for Metal Recovery from Copper Tailing

Abstract

It has been reviewed that the Cu, Fe, and Mn are harmful to our environment, it needs our consideration to recover the water which has been contaminated by these metals and as well as when released without being treated and recovered, it will be harmful to the land and the soil and can be unfriendly for our environment. Toxic mining waste is a problem of more serious concern for both industries and the government. Several copper tailings dumps have been abandoned and not sufficiently stabilized. Once the tailings containing toxic minerals and residual metals contact diluents like rainwater, it forms acid mine water that can leach metals into groundwater, rivers, and streams. The effect of the different HCl addition was investigated under a fixed S: L of 1:2. The leaching temperature was set to 40°C, and leaching occurred for 2h. As presented in Tables 1 & 2, the leaching efficiency of the metals increased gradually with an increasing amount of HCl. The AAS method showed the leaching efficiency of 0.03±0.01% and 0.04±0.02% for Cu with the addition of 1.5 and 2 mL/g of HCl. For Fe, leaching efficiencies of 17.38±3.55% and 15.94±2.41% were obtained with the addition of 1.5 and 2mL/g of HCl. However, 0.39±0.02% and 0.38±0.01% for Mn were leached when adding 1.5 and 2mL/g of HCl. Statistically, there was a non-significant (p<0.05) difference in the leaching efficiency of Cu, Fe, and Mn among the different concentrations of HCl. Using the XRF method, the leaching efficiency of 12.09±2.40% and 9.5±1.84% for Cu was obtained by adding 1.5 and 2mL/g of HCl. For Fe, leaching efficiencies of 1.5±0.11% and 1.35±0.05% were obtained with the addition of 1.5 and 2mL/g of HCl. However, 16.54±5.21% and 15±2.49% for Mn were leached when adding 1.5 and 2mL/g of HCl. Statistically, there was a non-significant (p<0.05) difference in the leaching efficiency of Cu, Fe, and Mn among the different concentrations of HCl. It is concluded that Cu, Fe, and Mn from the low-grade copper tailing are successfully recycled via H2SO4 leaching and subsequent fractional precipitation technology. Based on the mineral composition analysis results, leaching temperature, the amount of H2SO4 added, leaching time, and S:L have been evaluated for leaching efficiencies. The amount of H2SO4 added, and S:L have strongly influenced the leaching efficiency.