Gold recovery from alkaline cyanide solutions by electrochemical elution of strong-base anionic polymeric resins

This work presents experimental results for the recovery of gold present in alkaline cyanide solutions by using the electroelution technique of strong -base anionic polymeric resins IRA 402-CL from Rhom and Haas-Brazil Ltd. lo aded with gold. This technique of electroelution of anionic polymeric resin s is based on the removal of metal ions adsorbed to the resin, resulting fr om a potential difference applied between the cathode and anode in an elect rolytic cell. The electrolytic cell was composed of an aqueous solution wit h suitable chemical characteristics and an anionic polymeric resin bed load ed with gold. The resin used in the experiments was loaded using synthetic alkaline gold cyanide solution with 1.0 g/L of gold. The variables studied were electroelution time, cathode current density, distance between cathode and anode and the electrolyte chemical composition. Statistical methods ma de it possible to establish the optimum conditions that would achieve satis factory gold recoveries by the electroelution technique. The statistically predicted response for the resin loaded with gold by percolation was 16.5% gold recovery, 2.0 A/m(2) cathode current density, 20-mm distance between e lectrodes and 6.0 hrs electroelution time. For the centrifuging system, the statistically predicted response was 7.41% gold recovery under the followi ng conditions: 0.25A/m(2) cathode current density,1-mm distance between ele ctrodes, 3.5 hrs electroelution time and 10.9% NaOH in the electrolyte chem ical composition.