铜离子对银电解的影响

采用电导率仪测定不同Cu2+浓度下AgNO3溶液的电导率,应用扫描伏安法研究Cu2+对阴极极化的影响,通过恒电流电解精炼研究Cu2+浓度对电解银粉含铜量的影响。结果表明:AgNO3溶液的电导率随着Cu2+浓度的增加而逐渐升高;Cu2+对银的析出具有抑制作用,随着其浓度的增加银的析出电位负移;电解液Cu2+浓度超过21.3 g/L时,银粉铜含量便会超标;银电解液中的Cu2+浓度在10~20 g/L范围时,对银粉中其他杂质元素Bi、Fe、Pb、Te的析出具有抑制作用。

The Effect of Copper Ion on Silver Electrolysis

Theconductivity of AgNO3 solution with different Cu²⁺ concentration was measured by conductivity meter. The effect of Cu²⁺ on cathodic polarization of Ag was investigated by the liner sweep voltammetry. Constant current deposition experiments were used to study the effect of Cu²⁺ concentration on copper contamination of silver power. The results showed that theconductivity of AgNO3 solution increased with increasing Cu²⁺ concentration. The Cu²⁺ has an inhibition effect on reduction of Ag. The cathodic reduction potential of Ag shifted to negative-direction with the increment of Cu²⁺ concentration. The silver contains an excessive level of copper when Cu²⁺ concentration is above 21.32 g/L. The content of impurity elements such as Bi, Fe, Pb and Te are lower when Cu²⁺ concentration is between 10~20 g/L.