Recovery of Copper, Nickel and Zinc from Sulfate Solutions by Solvent Extraction Using LIX 984N

Recovery of valuable metals such as copper, nickel and zinc from synthetic sulfate solutions using LIX 984N as the extractant dissolved in kerosene was investigated. The metals get extracted at different equilibrium pH of the aqueous phase and thus the pH of the aqueous solutions forms the basis of their separation. Copper was extracted at an equilibrium pH of 3.5, while nickel and zinc get extracted at an equilibrium pH of 7.3 and 8.8 respectively. The extraction isotherms of copper, nickel and zinc were obtained by contacting the respective metal solutions and 0.05 M LIX 984N at different A:O phase ratio at their respective equilibrium pH of maximum extraction. A two-stage counter-current extraction simulation was done to achieve quantitative extraction of the metals. Furthermore, a two-stage counter-current stripping simulation yielded quantitative recovery of the individual metals, from their loaded organic phases. On the basis of the results, a flow sheet of the process has been developed.