金氰化溶解过程的电化学行为及形貌特征  

Electrochemical Performance and Morphology of Gold Dissolved in Cyanide Solution

作　　者：陈利娟 李骞[2] 杨永斌[2] 钟强[2] 何威[1] 王明[1] CHEN Li-juan;LI Qian;YANG Yong-bin;ZHONG Qiang;HE Wei;WANG Ming(Hunan Nonferrous Metals Vocational and Technical College,Zhuzhou 412006,Hunan,China;School of Minerals Processing&Bioengineering,Central South University,Changsha 410083,Hunan,China)

机构地区：[1]湖南有色金属职业技术学院,湖南株洲412006 [2]中南大学资源加工与生物工程学院,湖南长沙410083

出　　处：《矿冶工程》2021年第4期88-92,共5页Mining and Metallurgical Engineering

基　　金：国家自然科学基金(51574284)。

摘　　要：运用三电极体系的动电位法测定金氰化溶解过程的电位-时间曲线、交流阻抗曲线、循环伏安及Tafel曲线,结合微观检测,研究了金在NaCN溶液中的电化学行为。结果表明,金电极表面保护性产物生成、附着、沉积成膜,但沉积膜不断发生溶解,当成膜速度与溶解速度达到平衡时,金表面被钝化,因而金在NaCN溶液中具有较好的耐腐蚀性能;金在NaCN溶液中发生3次不同氧化溶解反应,3个峰对应的电位分别为-0.25 V,0.3 V和0.7 V,对应的峰电流强度依次为0.45 mA,0.5 mA和1.2 mA;金氰化溶解过程形成中间产物(AuCNads)并在电极表面累积成为保护膜,而羟基基团(—OH)在其表面或金电极上直接吸附,使电极表面失活,避免金电极进一步溶解;CN-与Au的电化学反应步骤是金电极溶解过程的控制步骤。The electrochemical performance of gold in NaCN solution was studied based on measuring and plotting the potential vs time curve,AC impedance curves,cyclic-voltammetry curve and Tafel curve by using the dynamic potential method with three-electrode system.Results show that,a kind of protective matter is generated and attached to the surface of the gold electrode,forming a heavy layer of deposited film or passivation film,which,however,is continuously dissolved.As the filming speed and the dissolving rate are in equilibrium,the gold electrode surface is gradually deactivated,resulting in the gold with better corrosion resistance in NaCN solution.The cyclic-voltammetry curve shows that three peaks occur at the potential of-0.25 V,0.3 V and 0.7 V respectively,with the corresponding current intensity of 0.45 mA,0.5 mA and 1.2 mA,indicating that the gold electrode undergoes three different modes of oxidative dissolution in NaCN solution.It is found that with gold in the cyanide solution,the AuCNads is generated and deposited on the surface of the electrode,forming a protective film,while the—OH is adsorbed on the surface of AuCNads or gold electrode,resulting in gradual deactivation of the electrode surface,which hinders the further dissolution of gold electrode.Besides,the dissolution process is controlled by the electrochemical reaction of CN-and Au.

关 键 词：金 金电极 氰化浸金 电化学行为 溶解 钝化 

分 类 号：TF111[冶金工程—冶金物理化学]