A process for recovering a precious metal from a sulfidic material comprises the steps of preparing an acidic aqueous halide solution having an oxidation potential sufficient to oxidise the sulfidic material and render the precious metal soluble in the solution, adding the material to the acidic aqueous halide solution so that the sulfidic material is oxidised and the precious metal is solubilised and separating the precious metal from the oxidised sulfidic material. In addition, a process for removing a contaminant from a contaminated sulfidic material comprises the steps of mixing the material in an aqueous solution wherein a multi-valent species of a relatively high oxidation state oxidises the contaminant to render it soluble in the solution, produces a contaminant refined material, and is reduced to a relatively lower oxidation state; and removing the contaminant from the solution whilst regenerating the multi-valent species to its relatively high oxidation state.