中国科学院地球化学研究所机构知识库

We investigated the influence of dissolved calcium fluoride, CaF2(aq), on the electrochemical dissolution of pyrite and the corresponding environmental effects on acid mine drainage (AMD). The experimental results showed that CaF2(aq) promotes pyrite electrochemical dissolution. When the CaF2(aq) concentration increased from 0 to 10 mg L-1 up to saturation, the promoting efficiency was 15.80 and 57.25%, respectively. The reason for this phenomenon is that F- and Fe2+ form FeF2, and at a higher scan potential, F- and Fe3+ form the ion complex FeF63- The mechanisms include: (i) the decreasing charge transfer resistance at the double layer due to the iron fluorine complex formation; and (ii) the decreasing passivation resistance at the cover layer due to the strong penetration of F-ions through it into the double layer. Although the hydrolysis reaction of F-in solution could increase the pH value of mine drainage, the AMD was significantly aggravated because CaF2(aq) promoted the pyrite electrochemical dissolution.