(中南工业大学冶金物理化学研究所, 长沙410083)
摘 要: 以高温合成法制备了FeS,用电位扫描、 旋转电极、恒电位电解等技术研究了FeS在电解液0.5 mol/L H2SO4+0.5mol/L K2SO4 (25℃, pH=0.70)中的阳极氧化过程。结果表明, FeS阳极氧化过程遵循“活性氧化—钝化—活性氧化”规律,在0.7~1.4 V (vs SCE)之间出现钝化区。第一个活性氧化区的Tafel方程为η=0.468+0.0289 lnJ, 在高过电位区, FeS阳极反应受固相扩散传质步骤控制,有少量高价态的S化合物生成。
关键字: FeS; 磁黄铁矿; 阳极氧化
(Institute of Metallurgical Physiochemistry,
Central South University of Technology, Changsha 410083,P.R.China)
Abstract:FeS was synthesized with Fe and S at high temperature. The electrochemical techniques, such as potential sweep, rotated disc electrode, and coulometry, were employed to probe the anodic oxidization behavior of FeS in the solution of 0.5 mol/L H2SO4+0.5 mol/L K2SO4 (0.25℃, pH=0.70). Experimental results demonstrated that the anodic oxidization behavior obeys the mode of activation oxidization—passivation—activation oxidization. Passivation occurs in the range of 0.7~1.4 V (vs SCE). The Tafel equation for the first activation oxidization zone isη=0.468+0.0289lnJ. Under the condition of higher overpotential, the anodic reactions are controlled by the step of the Fe solid diffusion. The products in anodic process are Fe3+ and S, and a small amount of sulfur compound with high valence is produced under higher overpotential.
Key words: FeS; pyrrhotite; anodic oxidization