Separation behavior of trace impurities during deep purification of zone-fused germanium tailings via vacuum distillation

Germanium is an important semiconductor material. With its wide application in high precision industries such as infrared optics, photovoltaics and semiconductor devices, the purity of elemental germanium has been put forward with higher requirements. This research focuses on the environmentally friendly vacuum distillation purification of zone-fused germanium tailings (99.98 %) to separate low-boiling-point trace impurities such as Zn, In, and Mg. These impurities hinder the preparation of ultrapure germanium (7 N). We propose a novel vacuum distillation-based deep purification process to effectively separate trace impurities in the zone-fused germanium tailings. The initial germanium and purified germanium are comprehensively analyzed using glow discharge mass spectrometry. Our vacuum purification results indicate that the impurity content is below 0.05 ppm for all elements except As. The As content reaches 0.87 ppm with a removal ratio of 96.1 %, resulting in elementary germanium with 99.9995 % purity. This method considerably increases the recovery ratio of germanium-rich secondary resources to over 95 % while efficiently eliminating low-boiling-point trace impurities such as Zn, Mg, and Pb from the zone-fused germanium tailings. The findings suggest the method's substantial potential for industrial application. This study offers valuable insights into the deep purification and front-end preparation of high-purity germanium.