氨络合物体系中杂质Zn²⁺对电沉积镍的影响

来源期刊：中国有色金属学报2009年第11期

论文作者：郑国渠 曹华珍 秦爱玲 杜征峥

文章页码：2044 - 2049

关键词：镍；锌；氨络合物；阴极过程；电结晶

Key words：nickel; zinc; ammonia complex; cathodic process; electrocrystallization

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。

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.

基金信息：国家自然科学基金资助项目
浙江省重大科技专项基金资助项目