Experimental study of pyrite–galena mixed potential in a flowing system and its applied implications

Abstract

A three-electrode system was adopted to investigate the corrosion current density and mixed potential of unstrained pyrite–galena and strained pyrite–galena galvanic cells in a flowing system. The results showed that when present in the same solution, strained pyrite produces a lower electrode potential than that of the galena electrode because of its strain energy; moreover, increasing the sodium sulfate solution concentration causes only slight fluctuations in the corrosion current density and mixed potential, while these values clearly increased with increasing ferric sulfate solution concentrations. In addition, for the sodium sulfate solution or ferric sulfate electrolyte, the faster the flow rate, the bigger the corrosion current density and the more positive the mixed potential of the galvanic cell. The experimental results are significant for hydrometallurgy and for controlling environmental pollution in mining activities. By using the galvanic model, mixed potential theory and the Butler–Volmer equation, the experimental results were explained theoretically.