USE OF CHLORINE ELECTROGENERATED FROM NaCl IN ACID MEDIUM AS A PROPOSAL FOR THE LEACHING OF ALLUVIAL GOLD

Abstract

Anodic electrogeneration of molecular chlorine from sodium chloride in an electrolytic cell produces a hypochlorous acid solution in an aqueous medium. This mixture of chloride and hypochlorous was used to leach gold from alluvial ore to its complex forms, [AuCl2]-, [AuCl4]-. The optimal amounts of NaCl in a neutral medium for gold leaching was 10 g L-1, while at pH 2, with a fixed NaCl concentration of 10 g L-1 it was observed a gold leaching increment of 70.4%. The addition of sodium hypochlorite to a solution of sodium chloride at pH 2 shows that it is the chloride oxidized product that performs the function of oxidant and can be used successfully for gold recovering from alluvial ore without the use of mercury.