辉铜矿生物浸出电化学机制及动力学研究  

A Study on Electrochemical Fundamentals and Kinetics of Bioleaching of Chalcocite

作　　者：武彪 廖勃 刘学 温建康 Wu Biao;Liao Bo;Liu Xue;Wen Jiankang(National Engineering Laboratory of Biohydrometallurgy,GRIMAT Engineering Institute Co.,Ltd.,Beijing 101407,China)

机构地区：[1]有研工程技术研究院有限公司生物冶金国家工程实验室

出　　处：《稀有金属》2019年第12期1332-1337,共6页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51574036)资助

摘　　要：采用Tafel法、交流阻抗法和恒电位阶极化法研究了辉铜矿生物浸出过程电化学行为,测定了腐蚀电化学动力学参数,确定了所发生的电化学反应。并结合第一性原理计算,分析了辉铜矿晶体结构性质变化,从电子结构和电化学角度揭示了细菌、 pH值和温度等因素对辉铜矿浸出的影响规律,查明了辉铜矿浸出过程主要影响因素及控制步骤。结果表明, pH值和温度对腐蚀电流和腐蚀电位影响显著,降低pH值和升高温度,降低了化学反应的吉布斯自由能,升高了阳极腐蚀电流密度,有利于辉铜矿电化学腐蚀反应的进行。辉铜矿溶解过程中生成了大量的CunS多硫产物和S膜钝化层,导致电荷传递量较少,是阻碍辉铜矿氧化溶解的关键因素。细菌的存在,氧化Fe2+增加了空穴浓度,提高了反应速率。同时,提高了溶液中的电位,阻抗弧变小,促进了多硫化物和S膜的氧化,从而加速了辉铜矿的氧化溶解。The electrochemical kinetics parameters of corrosion of chalcocite in bioleaching systems were studied by Tafel method, electrochemical impedance spectroscopy(EIS) method and constant electric potential polarization method, and determined the electrochemical reactions. The changes of crystal structure and properties of chalcocite had been ascertained by first-principles calculation. Based on the first-principles calculation, the change of crystal structure and properties of chalcopyrite was analyzed. The reason why bacteria, pH and temperature accelerated the oxidation rate of chalcocite was explored based on electronic microstructure and electrochemical dynamics. The main influencing factors and control steps of leaching of chalcocite were identified. The results showed that pH value and temperature had significant effects on corrosion current and corrosion potential, decreasing pH value and increasing temperature couldreduce Gibbs free energy of chemical reaction and increase current density of anodic corrosion, which was beneficial to the electrochemical corrosion reaction of chalcocite. During the dissolution of chalcocite, a large number of polysulfide intermediate(CunS) layers and S films were formed, the surface passivation resulted in less charge transfer, which was the key factors of hindering the oxidative dissolution of chalcocite. The presence of bacteria could increase the holes concentration and reaction rate. At the same time, the potential of the solution was increased by oxidizing Fe2+, the impedance arc was reduced, the oxidation of polysulfides and S films was promoted, and the oxidative dissolution of chalcocite was accelerated.

关 键 词：辉铜矿 电化学动力学 生物浸出 

分 类 号：TF111.3[冶金工程—冶金物理化学]