Abstract: High-purity copper has been widely used in semiconductor materials, optoelectronics and other fields due to its excellent physical and chemical properties such as ductility, thermal conductivity and electric conductivity. With the rapid development of electronic information industry, the copper product with high purity is pressing needed. Numerous methods such as zone melting, electron beam melting and electrolytic refining have been developed for the preparation of high-purity copper. Among these technologies, electrolytic refining has been investigated extensively and used in the industrial production for high-purity copper owing to its operation flexibility, simple-process and environmental-friendliness. In general, the electrolytic refining methods for the preparation of high-purity copper could be divided into nitric acid system and sulfuric acid system electrolytic refining. The electrolytic refining for high-purity copper preparation in sulfuric acid system has been widely used in industry. However, the high-purity copper prepared in sulfuric acid system generally contains the higher content of impurity elements such as S than in nitric acid system. Therefore, in this study, the 5N purity of copper was prepared from the raw materials of 4N copper in nitric acid system by one-step electrorefining. The effects of H2O2 addition, current density, electrolyte pH, Cu2+ concentration during the electrorefining process were systematically studied. Under the optimum conditions of Cu2+ concentration of 80 g/L, pH of 1.0, H2O2 addition of 0.10 mL/100 mL, and current density of 200 A/m2, the electrolytic product deposited on the cathode surface exhibited the smooth morphology, and the current efficiency during the electrorefining process was over 97%. Furthermore, the impurity elements including S, Ni, Se, As, Sb, Pb, Bi in the electrolytic product were detected by ICP-MS. The results showed that the purity of the copper prepared under the optimum conditions reached the 5N grade, which was consistent with the national standard of 5N high-purity copper.

Key words: high-purity copper, electrolytic refining, nitrate system, current efficiency, cathodic deposition

摘要： 高纯铜具有优良的延展性、导热性、导电性及较为稳定的化学性质，在半导体材料、光电子等领域应用广泛。本研究采用硝酸体系作为电解质，以4N金属铜为原料，一步电解精炼制备纯度为5N的高纯铜，系统研究了H2O2添加量、电流密度、电解液pH、Cu2+浓度等因素对电解过程的影响。结果表明，硝酸体系电解精炼制备高纯铜的最佳工艺条件为Cu2+浓度为80 g/L、pH=1.0、H2O2加入量为0.10 mL/100 mL、电流密度为200 A/m2。在该条件下进行电解精炼，阴极沉积的高纯铜表面光滑平整，电流效率达到97%以上。对最佳条件下获得的阴极产物进行ICP-MS检测，其中S, Ni, Se, As, Sb, Pb, Bi等常见杂质元素含量均符合5N高纯铜的国家标准。

关键词: 高纯铜, 电解精炼, 硝酸体系, 电流效率, 阴极沉积