电位对天然黄铜矿表面膜层性质的影响

采用循环伏安（CV）、扫描电子显微镜（SEM）和电化学阻抗谱（EIS）研究黄铜矿在含有5×10-4mol/L乙黄药溶液中的电化学行为以及电位对黄铜矿表面膜层成分和性质的影响。结果表明：在开路电位（OCP）下,天然黄铜矿表面发生黄药阴离子的吸附过程;在阳极电位范围-0.11～0.2V内,主要发生黄药阴离子氧化形成疏水双黄药膜层的电化学过程。形成的双黄药膜层在电位为0V时具有较高覆盖度和较大的厚度,随着电位的增加表面双黄药膜层的覆盖度和厚度减小。当电位高于0.2V时,黄铜矿表面发生以自身活化溶解为主的电化学过程,黄铜矿表面由双黄药膜层转化成为大量具有多孔和疏松结构的含有Cu（Ⅱ）和Fe（Ⅲ）的氧化物。

Effect of potential on characteristics of surface film on natural chalcopyrite

Electrochemical behavior of natural chalcopyrite in electrolyte solution containing 5×10⁻⁴ mol/L ethyl xanthate, and the effect of potential on the composition and characteristics of surface film were studied by cyclic voltammetry (CV), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The adsorption of xanthate (X⁻) occurred on the mineral surface at open-circuit potential (OCP). In the potential range from −0.11 to 0.2 V, the electrochemical reaction related to the formation of the hydrorphobic film of dixanthogen (X₂) occurred on natural chalcopyrite surface. This surface film had high coverage and large thickness at the potential of 0 V, but it had low coverage and small thickness at the potentials of 0.1 V and 0.2 V. Electrochemical activation started to occur when the potential was higher than 0.2 V, and the film of X₂ transformed to plenty of Cu(II) and Fe(III) oxygen-containing species which had the porous and loose characteristics.