用电化学研究表面膜抑制黄铁矿氧化效果

Electrochemical study on suppression of pyrite oxidation by coating

运用伏安法研究了表面包膜后的黄铁矿电极的电化学行为。黄铁矿电极在 0 2 0mol/LNa2 SO4 溶液 (pH4 5 )中 ,扫描电势在 0 15～ 0 5 5V (相对于标准氢电极SHE)内 ,无明显的阳极氧化电流出现 ;而当电势大于 0 6 0V时 ,电流呈指数式的急剧增加 ,作为阳极的黄铁矿电极发生强烈的氧化反应。黄铁矿电极表面经pH 3 ,5和 7的 0 10mol/LH2 O2 与0 0 5 %配合剂混合液成膜处理 2和 6h后 ,电流—电势曲线上的电流明显减小。上述结果表明 ,表面膜有显著抑制黄铁矿氧化的作用 ,但阳极氧化电流不能消失。说明矿石表面形成的难溶膜不能杜绝黄铁矿的氧化 。

Electrochemical behavior of pyrite eletrodes treated with chelating agent was studied using voltammetry in 0 20 mol/L Na 2SO 4 solution(pH 4 5).Small currents were observed on the voltammograms of pyrite electrodes during the linear potential scan from 0 15 to 0 55 V vs.SHE(standard hydrogen eletrode),indicating that no anodic oxidation took place.When the scan potential was higher than 0 60 V vs.SHE,an expotential increase in current was observed,indicating occurence of pyrite oxidation.When the pyrite electrodes were treated with the solution containing 0 10 mol/L H 2O 2 and 0 05% chelating agent for coating at pH3,5 and 7 in 2 hours and 6 hours,the anodic current decreased obviously.The results showed that the coating on pyrite surface could suppress the electrochemical oxidation of pyrite effectively.But,the coating could not eliminate pyrite oxidation completely,which was dependent on the quality of coating and impurity on pyrite surface.