黄铁矿在酸性体系下的电化学研究

Electrochemical Study on Pyrite in Acidic Medias

在酸性体系下运用循环伏安、稳态极化扫描、Tafel曲线和交流阻抗等多种电化学方法对黄铁矿电极的电化学氧化机理及电化学腐蚀动力学进行了研究。结果表明:黄铁矿在氧化电位较低时首先被氧化成FeS,覆盖于电极表面,使电极表面发生钝化,随着电位的继续升高,黄铁矿氧化形成Fe2+;不同pH、不同温度下的Tafel曲线研究表明,降低体系的pH值和升高体系温度均有利于提高腐蚀电流密度,即有利于黄铁矿的氧化;不同电位下电极表面所处的控制过程也不相同,测定结果与循环伏安曲线的研究结果相吻合。

The electrochemical oxidation behavior and corrosion kinetics of pyrite in acidic media was investigated by cyclic voltammetry,polarization curves,Tafel curves and electrochemical impedance spectroscopy.The results show that pyrite is oxidized to FeS,which makes electrode passivated;as the potential continue to increase,pyrite is oxidized to Fe2＋.The research of corrosion kinetics at different pH values and temperature shows that the corrosion current density decreases as pH values increase;the corrosion current density increases as the temperature rises.It furtherly indicates that decreasing pH value or increasing temperature in the study range of pH value and temperature accelerates the corrosion process of pyrite.The study o f electrochemical impedance spectroscopy indicates controlling step of pyrite oxidation is different at different potentials,which is consistent with the result of cyclic voltammetry.