粗锡真空蒸馏精炼的研究

Refinement of Crude Tin by Vacuum Distillationon Industrial Scale

针对粗锡火法精炼工艺中砷、锑无法有效开路的问题，采用“真空挥发-分级冷凝”技术，对粗锡进行真空蒸馏精炼工业试验，控制炉内残压10～30Pa，蒸馏温度1200～1400℃，日处理量18～20t，可得到含锡99．575％的产品粗锡，超过70％的砷锑可以蒸馏脱除，得到金属砷和锡铅锑合金，从而减少精炼渣的产生，大大降低环境与安全风险。

A novel environmental friendly technique was developed to remove the As and Sb impurities from the crude tin （with Cu and Fe removed in advance） on industrial scale by a combination of vacuum distillation and multi- stage condensation. The impact of the distillation conditions, including but not limited to the distillation temperature and time, pressure, daily-processing capacity, and multi-stage condensation, on the removal rates of As and Sb and extraction rate of Sn were theoretically analyzed and experimentally evaluated. The preliminary results show that the new technique is capable of refining the crude tin by removing most of As and Sb impurities. For instance, under the conditions： a tempera- ture in 1200 ～ 1400℃ range,a pressure in 10 ～ 30 Pa range and with a daily-processing capacity of 18 - 20 t/d,the pu- rity of the distilled Sn was 99.575% （wt）, because over 70% of the As and Sb impurities were removed and turned into metallic As and Sn-Pb-Sb alloy.