Preparation of high-purity copper through vacuum distillation

Copper is capable of maintaining strong competitiveness in the metal materials market for its prominent ductility, thermal conductivity, and electrical conductivity. As more rigorous purity requirements of industrial sputtering targets and aerospace have been raised, the clean and efficient production of high-purity copper turns out to be an urgent problem over the past few years. In this paper, the possibility of removing impurities from copper melt was investigated by integrating theoretical calculations and experiments, and the separation coefficient and vapor-liquid equilibrium phase diagram of copper and impurity elements were determined and plotted using the molecular interaction volume model (MIVM). Moreover, the effects of the distillation temperature, the holding time, and the system pressure on the experimental results were discussed. As indicated by the results, with the rise of the temperature and with the extension of the holding time, the purity of copper was first increased and then decreased, and the purity of residual copper reached 99.9993% at 1473 K temperature, 1.5 h holding time, and 5 Pa pressure, and the method effectively separated impurities from copper raw materials. Besides, no waste water or waste gas emission was generated in the experiment.