A novel process for directional impurity removal and preparation of front-end high-purity antimony from crude antimony

Abstract

Aiming to separate the trace impurities in crude antimony and to provide a foundation for the preparation of front-end high-purity antimony, two processes of low temperature-high temperature vacuum distillation (LHVD) and high temperature-low temperature vacuum distillation (HLVD) were performed for the deep purification of crude antimony. The removal rates of Bi, Zn, and Cd from products using LHVD were 77.20 %, 34.78 %, and 27.82 %, respectively, under the optimal conditions of 1–10 Pa, a holding time of 90 min, a low-temperature stage of 873 K, and a high-temperature stage of 923 K. The content of impurities in antimony was 39 ppm, and samples with antimony content 9999.61 ppm were obtained. The removal rates of Bi, Zn, and Cd from products using HLVD were 43.89 %, 83.51 %, and 56.21 %, respectively, under the optimal conditions of 1–10 Pa, a holding time of 90 min, a high-temperature stage of 923 K, and a low-temperature stage of 873 K. The impurity content in antimony was 52.94 ppm, and samples with antimony content 9999.47 ppm were obtained. The trace impurities in crude antimony can be effectively removed via a two-stage vacuum distillation. This study provides a reference for the deep purification and front-end preparation of high-purity antimony.