Evaluation of the protective effect of polysiloxane coating on pyrite with electrochemical techniques

The efficiency of polysiloxane coating to suppress the pyrite oxidation under environmentally relevant conditions was investigated with electrochemical techniques. Cyclic voltammogram, Nyquist plot or Tafel test were preformed in the conditions of different polysiloxane proportions in modifying agent, pH values, Fe3+ concentrations and volumes of water impact. The increased proportion of polysiloxane in the modifying agent would enhance the protective effect of the coating. The modifying agent with the least proportion of polysiloxane was used in subsequent experiments to illustrate the excellent passivation of polysiloxane. The results indicated that coating on the pyrite had good protective effect to resist the oxidation of pyrite in the aggressive condition of pH 2. Moreover, there were no distinctive differences in coated pyrite behaviors during anodic oxidation in solutions with different pH values. Furthermore, in a wide range of Fe3+ concentrations, the coating on the pyrite still showed good effect to retard the pyrite oxidation. Finally, the coating on the pyrite possessed good washing durability. Therefore, polysiloxane coating had great potential to develop a new AMD suppression strategy. (C) 2013 Elsevier Ltd. All rights reserved.