Aqueous Pretreatment Effect to Improve Au, Ag, and Pt Recovery from Spent Automotive Catalysts

Automotive catalysts represent a secondary source for precious metals recovery. These elements are usually obtained from minerals. Recently, methods have been sought to recover them waste materials. The main route consists of pyrometallurgical treatments at high temperatures with the generation other pollutants and very energy consumption. With hydrometallurgy, routes can be developed which favor aqueous extraction said room temperature. In an automotive catalyst, there different interfere in recovery process. this study, sodium citrate (Na3C6H5O7•H2O), nitric acid (HNO3), hydrochloric (HCl) were evaluated as hydrometallurgical pretreatment dissolve Fe, Zn, Pb contained spent catalyst improve subsequent therein (Au, Ag, Pt). Afterwards, thiourea (SC(NH2)2) was carried out, comparing effect reagents. Finally, feasibility each analyzed aim avoid processes temperatures.