Effect of Inorganic Anions on FeS Oxidative Dissolution

The oxidative dissolution of FeS at 30 °C in aerated aqueous solutions in the 5.5-6.0 pH range in the presence of inorganic anions (NO3− and Cl−) was investigated by a potentiodynamic polarization method. The corrosion current Icorr increased with increasing [NO3−] and [Cl−], demonstrating the ionic nature of activated complex of FeS oxidative dissolution. The corrosion potentials (Ecorr) varied between -367.4 mV (in 0.25 M NaCl) and -277.5 (in 0.5 M NaNO3). These results indicate that the FeS stability may be significantly affected by a change in the c omposition of natural water, and imply that any dissolution model at the FeS surface should also take into account the specific impact of these anions.