Separation and purification Sb2S3 from stibnite by vacuum distillation

Stibnite is the main raw material employed to produce antimony. With the excessive exploitation of high-grade stibnite, low-grade stibnite become more and more important. This study aimed to introduce a vacuum process for recovering and enriching antimony from low-grade stibnite. At the pressure of 10 Pa, by controlling heating temperature, Sb2S3 and Sb2O3 from stibnite (12.8 wt% Sb) was evaporated and enriched. We investigated the influence of vacuum distillation temperature and time on the recovery of low-grade Sb2S3. The result indicated antimony recovery could reach about 97% for suitable vacuum distillation conditions, and the purity of Sb2S3 was about 95 wt%. As for high-grade stibnite, through two-step vacuum distillation, Sb could not only be recovered in the form of Sb2S3, but also purified to commercial Sb2S3 with a purity about 99.5 wt%. The results demonstrated that vacuum distillation is a possible way to recover antimony from low-grade stibnite and purify Sb2S3 from high grade stibnite.