Electrochemical dissolution of chalcopyrite in the presence of thiourea and formamidine disulfide

The effects of thiourea (TU) and formamidine disulfide (FDS) on the electrochemical dissolution of chalcopyrite in sulfuric acid solution and at ambient temperature were assessed. The corrosion current densities of a CuFeS2 electrode were estimated using electrochemical impedance spectroscopy and linear polarization. TU and FDS enhance the dissolution kinetics of CuFeS2. TU may adsorb on the surface of the electrode and favor the formation of pits and the dissolution of the passive film, thus forming sites that are more electrochemically active. FDS behaves as an oxidant and can leach chalcopyrite in the absence of other oxidizers. Electrochemical results are compared to column leaching results where it is shown that the effects of TU are qualitatively similar.