Direct copper recovery from pregnant leaching solutions (PLS), using a custom electrolytic cell, based on reactive electrodialysis (RED)

Abstract

ABSTRACT This study shows the feasibility of recovering copper directly from Pregnant Leaching Solutions (PLS), using the reactive electrodialysis technique, without the need of solvent extraction. The copper PLS contained the following ion concentrations: Cu2+ 2.0–2.5 g/L; pH 1.5–1.8; 90–95 g/L; Cl− 8–10 g/L and total iron of 8–10 g/L. The copper electrowinning process is limited by the mass transport capacity of the system and by impurities that decrease the yield. To increase the selectivity and the copperproduction rate, a reactive electrodialysis (RED) cell was developed. The cell contained four compartments, two anion-exchangemembranes and a bipolar electrode to increase the production rate. This cell recovered copper and sulfuric acid at the anolytes. Thebest result was a current efficiency of 99% and specific energy consumption of 2.11 Wh/kg Cu using a current density of 80 A/m2 at 55°C and flow of 100 mL/s.