(浙江工业大学 化学工程与材料学院，杭州 310032)
摘 要: 通过霍尔槽试验研究氨络合物体系中杂质Zn2+对镍电沉积的影响，采用电化学工作站测试不同Zn2+浓度时的循环伏安曲线、稳态极化曲线及电流时间暂态曲线。结果表明：杂质Zn2+的含量为0.1 g/L时，在小于2.78 A/dm的电流密度范围内可正常沉积出金属镍；杂质Zn2+含量大于0.5 g/L时，在较大的电流密度范围内均无法正常沉积出金属镍；过电位小于640 mV时，Zn2+的存在不影响阴极反应的传递系数，且不改变阴极反应机理；当过电位大于640 mV，且杂质Zn2+的浓度大于0.5 g/L时，阴极反应的传递系数减小，阴极反应机理发生改变；杂质Zn2+浓度大于0.5 g/L时，严重影响镍电结晶过程的成核速率，这是其抑制金属镍电沉积的主要原因。因此，采用镍氨络合物体系电积金属镍，应控制杂质Zn2+的含量小于0.1 g/L。
关键字: 镍；锌；氨络合物；阴极过程；电结晶
（College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, China）
Abstract:In nickel ammonia system, the influence of impurity Zn2+ on the nickel electrodeposition was studied intensively by Hull Cell experiments, and the cyclic voltammetry, cathodic polarization and chronoamperometric curves were tested at different Zn2+ concentration by electrochemistry working station. The results show that nickel can be deposited normally when the concentration of impurity Zn2+ is 0.1 g/L and the cathodic current density is less than 2.78 A/dm. When the concentration of impurity Zn2+ is greater than 0.5 g/L, nickel can’t be deposited normally in a wide range of current density. The cathodic transfer coefficient α and reaction mechanism will not change with the addition of impurity Zn2+ when the overpotential is less than 640 mV. The cathodic transfer coefficient α decreases and the reaction mechanism changes when the overpotential is greater than 640 mV and the concentration of impurity Zn2+ is greater than 0.5 g/L. The nucleation rate during nickel electrocrystallization is restrained greatly when the impurity Zn2+ concentration is greater than 0.5 g/L, which is the main reason that inhibits the nickel electrodeposition. So, during electrowinning nickel from ammonia system, the content of purity Zn2+ should be controlled less than 0.1 g/L.
Key words: nickel; zinc; ammonia complex; cathodic process; electrocrystallization
