Natural versus synthetic pyrrhotite oxidation by dissolved oxygen

Abstract

The reaction of pyrrhotite with dissolved oxygen was studied at pH 2.5 and 25oC by electrochemical methods (potentiodynamic polarization, Electrochemical Impedance Spectroscopy (EIS) or Cyclic Voltammetry (CV)). It was found that there are differences between the reactivity of the natural and synthetic pyrrhotite, respectively. The natural pyrrhotite is more resistant to oxidation than the synthetic counterpart. The lower reactivity of the natural pyrrhotite can be explained by the formation of a higher amount of S(0) on its surface. EIS spectra indicate that the characteristics of the pyrrhotite/solution interface are essentially identical for both natural and synthetic pyrrhotite electrodes.