Copper leaching from electronic waste for the improvement of gold recycling

Gold leaching from EW-PBC, using 0.4 M Thiourea solutions at pH 1.5, during three hours. Pretreatment conditions: HCl: copper leaching for six hours with solution 0.5 M HCl with air sparging. Citrate: copper leach for six hours with 0.5 M citrate solution at pH 4.5 and addition of peroxide. M: Material without any preliminary treatment.88