Selective and efficient extraction of Cu(II) from a complex sulfate solution containing Co(II), Fe(II), Cu(II), and Zn(II) using DZ988N

DZ988N, a kind of chelating extractant, was used to separate copper from the sulfuric acid leaching solution of a polymetallic residue containing Co(II), Fe(II), Cu(II) and Zn(II), and its chelating mechanism was investigated. In order to optimize the DZ988N extraction process, the effects of DZ988N concentration (v/v), pH value of aqueous phase, extraction temperature, time and phase volume ratio (O/A) on metal extraction efficiency (eta(M)) and separation coefficient (beta(A/B)), were determined in detail. It was found that, under the optimal extraction conditions of DZ988N concentration (v/v) of 25%, pH value of aqueous phase of 2.0, extraction temperature of 25 degrees C, time of 6 min, and phase volume ratio (O/A) of 1/1.5, the single-stage extraction efficiency of Cu(II) was 97.53%, while Fe(II), Co(II) and Zn(II) were basically remained. In addition, extraction isotherms diagram (McCabe-Thiele diagram) was built to determine that a two-stage counter-current extraction is needed. Under the optimal conditions, the copper extraction efficiency was 99.92% and stripped rate was 99.2%. Finally, 99.63% Cu was enriched into the stripped solution with 7.85 g/L Cu2+, and 0.38% was lost.

Automated summary

DZ988N, a chelating extractant, was used to separate copper from a sulfuric acid leaching solution containing Co(II), Fe(II), Cu(II), and Zn(II), and its chelating mechanism was investigated. The optimal extraction conditions were determined to be a DZ988N concentration (v/v) of 25%, pH value of 2.0, extraction temperature of 25 degrees C, time of 6 min, and phase volume ratio (O/A) of 1/1.5. Under these conditions, the single-stage extraction efficiency of Cu(II) was 97.53%, while Fe(II), Co(II), and Zn(II) remained mostly unaffected. A two-stage counter-current extraction was determined to be necessary based on the extraction isotherms diagram. The copper extraction efficiency under the optimal conditions was 99.92% and the stripped rate was 99.2%, with a loss of 0.38%.