(中南大學(xué) 資源加工與生物工程學(xué)院， 長沙 410083)
摘 要: 在酸性體系下研究砷黃鐵礦的電化學(xué)氧化。 結(jié)果表明： 砷黃鐵礦首先被氧化為As2S2， 覆蓋于電極表面， 使電極表面發(fā)生鈍化； 隨著電位的繼續(xù)升高， As2S2被氧化生成亞砷酸， 隨后亞砷酸被氧化為砷酸， 亞鐵離子被氧化成鐵離子。 不同pH和溫度下的腐蝕動力學(xué)研究表明， 隨著pH值的增大， 體系的腐蝕電位正移， 腐蝕電流密度減小； 隨著溫度的升高， 砷黃鐵礦的腐蝕電位負移， 腐蝕電流密度增大。 說明在研究的pH及溫度范圍內(nèi)， 降低體系的pH或提高溫度都有利于砷黃鐵礦的氧化。 交流阻抗研究結(jié)果表明， 不同電位下電極表面發(fā)生的電化學(xué)反應(yīng)機理不同， 測定結(jié)果與線性掃描的研究結(jié)果相吻合。
關(guān)鍵字: 砷黃鐵礦； 電化學(xué)； 酸性介質(zhì)
（School of Resources Processing and Bioengineering, Central South University, Changsha 410083）
Abstract: The electrochemical research of arsenopyrite in acidic solution shows that arsenopyrite is firstly decomposed to As2S2, which coveres on the electrode and the dissolution of arsenopyrite is hence retarded. Then the As2S2 is oxidized to H3AsO3, H3AsO3 to H3AsO4, and Fe2+ is oxidized to Fe3+ 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.
Key words: arsenopyrite; electrochemistry; acidic media
