Selective extraction of copper from Cu-Zn sulfate media by new generation extractants

The selective recovery of copper(II) from Cu-Zn sulfate solutions using solvent extraction and N,N-dialkyl-N'hydroxypyridine-2-carboximidamides as extractants was investigated. Three compounds were synthesized and their extractability toward copper(II) and zinc(II) was studied. The influence of process parameters such as the pH of aqueous phase, shaking time, diluent type and also extractant's structure and concentration on efficiency of both metals ions extraction was presented. Results indicated that the equilibrium pH and type of the organic diluent had the biggest impact on the copper(II) extraction efficiency, its selectivity over zinc(II), and the stoichiometry of formed copper complex. Obtained experimental data were used to develop a method of copper (II) extraction from Zn-Cu sulfate solution composed of 40.9 g/L Zn(II) and 1.2 g/L Cu(II). A flowsheet was tested in laboratory-scale reactors and the conducted test confirmed the possibility to selective recover of Cu(II) over Zn (II), and the concentration of Cu(II).