title: Assessing the Influence of Calcium Fluoride on Pyrite Electrochemical Dissolution and Mine Drainage pH.
abstract: We investigated the influence of dissolved calcium fluoride, CaF(aq), on the electrochemical dissolution of pyrite and the corresponding environmental effects on acid mine drainage (AMD). The experimental results showed that CaF(aq) promotes pyrite electrochemical dissolution. When the CaF(aq) concentration increased from 0 to 10 mg L up to saturation, the promoting efficiency was 15.80 and 57.25%, respectively. The reason for this phenomenon is that F and Fe form FeF, and at a higher scan potential, F and Fe form the ion complex FeF. 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 CaF(aq) promoted the pyrite electrochemical dissolution.
authors.forename: Luying
authors.initials: L
authors.lastname: Wang
authors.forename: Qingyou
authors.initials: Q
authors.lastname: Liu
authors.forename: Kai
authors.initials: K
authors.lastname: Zheng
authors.forename: Heping
authors.initials: H
authors.lastname: Li
mesh_terms: D002124:Calcium Fluoride / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007501:Iron; D008906:Mining; D012995:Solubility; D013440:Sulfides; D014873:Water Pollutants / Q000737:chemistry*
chemical_list: D013440:Sulfides; D014873:Water Pollutants; C011342:pyrite; D007501:Iron; D002124:Calcium Fluoride