砷黄铁矿在酸性体系下的电化学氧化

在酸性体系下研究砷黄铁矿的电化学氧化。结果表明:砷黄铁矿首先被氧化为As2S2,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,As2S2被氧化生成亚砷酸,随后亚砷酸被氧化为砷酸,亚铁离子被氧化成铁离子。不同pH和温度下的腐蚀动力学研究表明,随着pH值的增大,体系的腐蚀电位正移,腐蚀电流密度减小;随着温度的升高,砷黄铁矿的腐蚀电位负移,腐蚀电流密度增大。说明在研究的pH及温度范围内,降低体系的pH或提高温度都有利于砷黄铁矿的氧化。交流阻抗研究结果表明,不同电位下电极表面发生的电化学反应机理不同,测定结果与线性扫描的研究结果相吻合。

Electrochemical oxidation of arsenopyrite in acidic media

The electrochemical research of arsenopyrite in acidic solution shows that arsenopyrite is firstly decomposed to As_2S_2, which coveres on the electrode and the dissolution of arsenopyrite is hence retarded. Then the As_2S_2 is oxidized to H_3AsO_3, H_3AsO_3 to H_3AsO_4, and Fe~ 2 is oxidized to Fe~ 3 with the increase of potential. The results attained at different pH and temperature show that the corrosion potential is positively shifted and the corrosion current density decreases with the increase of pH. While temperature increasing, the corrosion potential is negatively shifted and the corrosion current density increases. The results show that reducing the pH or raising the temperature of the system are advantageous to the oxidation of arsenopyrite. AC impedance measurements show that under different potentials, the mechanism of the arsenopyrite is different, which confirms satisfactorily the result obtained in linear polarization.