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; ${\mathrm{SO}}_4^{2-}$ 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.

This manuscript describes molybdenum recovery from copper Pregnant Leaching Solutions (PLSs) in the copper oxide mining industry with high contents of chloride ions. This product was recovered from the copper leaching pond solutions of the Chilean National Copper Mining Corporation (CODELCO) using the ion exchange process. This process recovered molybdenum from initial Mo concentrations of 50 mg/L using two different anion−exchange resins. The first experiments, with 1 g/L Cl⁻, achieved recovery yields of 90% and molybdenum concentrates as CaMoO₄. However, the process was permanently halted because of the early saturation of the ion exchange resins given by high chloride concentrations (10 g/L Cl⁻) of the original copper PLS and the significant reagent consumption given by the low adsorption capacity. Static studies were developed to determine the adsorption isotherms, followed by continuous molybdenum recovery tests. The Langmuir adsorption parameters were determined as a function of the chloride concentration, giving absorption capacities from 180 to 250 mg Mo/gram of resin and recoveries from 63% to 90%. The breakthrough values for the DOWEX and Lewatit resins for chloride contents of 10 g/L were 180 and 245 BV, respectively, while for 1 g/L, these values were 620 and 890 BV. This allowed obtaining elution solutions of 890 mg Mo/L for the DOWEX resin and 1000 mg Mo/L for the Lewatit resin.