DOI: https://doi.org/10.55373/mjchem.v26i1.240

Keywords: Gold; recovery; thiosulfate; hydrogen peroxide; yield

Abstract

Gold recovery from pregnant leach solutions like pregnant thiosulfate leach solutions from gold-containing solid wastes (e.g., e-waste) has gained considerable research attention in recent years due to the high market value and limited supply of gold. Although hydrogen peroxide (H2O2) is known as a green reducing agent since it liberates water and oxygen only as reaction by-products, recovery of gold from thiosulfate solutions via H2O2 reduction is still scarce. Hence, this work aimed to recover gold from thiosulfate solutions using H2O2 as a reducing agent. The reduction experiments were carried out by mixing gold(III)-containing thiosulfate solutions with H2O2, and the effects of different initial gold(III) concentrations (10-500 ppm), H2O2 concentrations (0.05-2 M), reaction temperatures (25-65°C) on the gold recovery yield were investigated. The highest gold yield of over 98% was achieved with an initial gold(III) concentration of 500 ppm and a H2O2 concentration of 2 M at 60°C. Therefore, H2O2 is a potential reducing agent for the recovery of gold from thiosulfate solution.