[Investigation on mechanism of pyrite oxidation in acidic solutions].
[Investigation on mechanism of pyrite oxidation in acidic solutions].
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发表时间：
2012-11
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通讯作者：
Nan Wang;X. Yi;Z. Dang;Yun Liu
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作者：
Nan Wang;X. Yi;Z. Dang;Yun Liu
以黄铁矿-碳糊电极为工作电极，采用开路电位、循环伏安、塔菲尔极化曲线和阳极极化曲线等电化学分析方法研究了酸性溶液中黄铁矿氧化的机理。结果表明，黄铁矿在酸性溶液中的氧化过程为两步反应：第一步是铁的溶解，形成由元素硫、贫金属硫化物和多硫化物组成的钝化膜;第二步是这些中间产物进一步氧化为SO 4（2-）。在酸性条件下，黄铁矿氧化的最终产物为Fe 3+和SO 4（2-）。随着硫酸溶液浓度的增加，开路电位和自腐蚀电位正移，峰电流和自腐蚀电流增大。这表明体系酸度的增加有利于黄铁矿的氧化。
The mechanism of pyrite oxidation in acidic solutions was investigated by electrochemical analysis methods, such as open-circuit potential, cyclic voltammetry, Tafel polarization curve and anodic polarization curve, using a pyrite-carbon paste electrode as working electrode. The results showed that the oxidation process of pyrite in acidic solutions was via a two-step reaction: the first step was the dissolution of iron moiety and formation of a passivation film composed of elemental sulphur, metal-deficient sulfide and polysulfide; the second step was the further oxidation of these intermediate products to SO4(2-). The final reaction products of pyrite oxidation were Fe3+ and SO4(2-) in acidic solutions. In addition, the open-circuit potential and corrosion potential were positively shifted, the peak current and the corrosion current were increased with the increase in concentration of H2SO4 solutions. This indicated that increased acidity of the system was advantageous to the oxidation of pyrite.