基于黏性蒸馏-气相分离的冶金级粗碲提纯方法

Purification of metallurgical-grade crude tellurium based on viscous distillation and gas-phase separation

开发一种基于黏性蒸馏-气相分离的高纯碲材料制备方法。通过调节冷凝器结构和冷凝温度,达到黏性蒸馏、控制碲优势冷凝区的目的,使挥发性差的物质留在残留物中,而硒在气相中与碲分离,实现冶金级粗碲的提纯。研究饱和蒸气压、碲分子平均自由程、不同冷凝位置的杂质分布特征以及冷凝物形貌。500 g级的实验结果表明,在5 Pa、773 K和90 min的最佳实验条件下,碲的直收率为83.40%,纯度高于99.9996%,碲优势冷凝区冷凝物中硒含量降低至2.76×10^(-4)%(质量分数)。

A method for preparing high-purity tellurium based on viscous distillation and gas-phase separation was developed.By adjusting the condenser structure and condensing temperature to achieve viscous distillation,the dominant condensation zone for tellurium was controlled;hence,poorly volatile substances remained in the crucible,while selenium was separated from tellurium in the gas phase to achieve the purification of metallurgical-grade crude tellurium.Specifically,the saturated vapor pressure,mean free path of tellurium,impurity distribution,and morphologies of the condensate at different locations were investigated in detail.The results for a 500 g upscaled experiment showed that the direct yield of Te was 83.40%,the purity of Te reached higher than 99.9996 wt.%and the selenium content in the dominant condensation zone was reduced to 2.76×10^(-4) wt.%under the optimal experimental conditions of 5 Pa,773 K and 90 min.