Solvent extraction and separation of copper and zinc from a pickling solution

Solvent extraction studies of copper and zinc have been carried out using Versatic 10 acid and Cyanex 272 separately from a model brass pickle liquor. Various parameters for the extraction and separation of copper and zinc such as effect of pH, extractant concentration, phase ratio etc. have been optimized. It was observed that copper was almost completely extracted into the organic phase comprising of 30% Versatic 10 acid at the equilibrium pH of 5.0 using the phase ratio of 1:1 whereas, zinc extraction was noticed at above pH 5.0. On the other hand the pH0.5 values were 3.5 and 4.6 for zinc and copper respectively with 20% Cyanex 272. The difference in pH0.5 value of 1.10 indicated the possible separation of Zn and Cu. By McCabe Thiele diagram number of stages required for the counter current extraction of copper and zinc has been determined for both the solvents. The stripping study showed that 1 mol/L H2SO4 was sufficient to strip metal ions in a single contact from each of the extractant.