Separation of copper, iron (III), zinc and nickel from nitrate solution by solvent extraction using LK-C2

After leaching of the waste printed circuit boards with HNO3, the leach liquor bearing 5.13 kg/m3 Cu, 0.63 kg/m3 Fe (III), 0.36 kg/m3 Zn, 1.31 kg/m3 Ni and 34.59 kg/m3 nitrate was obtained. Development of a solvent extraction flow chart for the separation and recovery of Cu, Ni and Fe (III) using LK-C2 as the extractant from nitrate solution was investigated. Extraction of the metals depends on the equilibrium pH in the aqueous phase and the increases with rise in equilibrium pH. Based on the difference in their extraction behavior as a function of equilibrium pH in the aqueous phase, it was possible to separate and recover copper, nickel and iron. Copper is extracted using 15% LK-C2 in kerosene at two stages at initial pH of 2.60 and the extraction percentage is 99.98%. Copper is stripped by 2.00 mol/L H2SO4 at three stages and the stripping percentage is 97.51%. Fe and Ni are extracted using 20% LK-C2 in kerosene at two stages at initial pH of 3.00 and 10.00, and the extraction percentages are 96.14 and 99.35%, respectively. Fe is stripped by 2.00 mol/L HCl at two stages and the stripping rate is 99.18%. Ni is stripped by 3.00 mol/L H2SO4 at three stages and the stripping percentage is 98.32%.