Removal of impurity Pb during crude selenium purification by controlling potential oxidation and vacuum distillation

A removal route of impurity Pb in crude selenium, controlling potential oxidation and vacuum distillation process was presented based on Eh-pH diagram of Pb-Se-H2O and Pb-Te-H2O system. Pb removal mechanism and behavior in the purification of selenium were investigated. The results showed PbSe and PbTe in crude selenium were oxidized to PbSeO3 and Pb2+, which effectively refrained volatilization of element Pb in the following vacuum distillation. Finally, 99.988% selenium product with 13.20 ppm Pb was obtained at 523 K, 60 min, 10 Pa. The study provides a theoretical basis and method for removing impurity Pb and has a potential application in deep eliminate impurity Pb from crude selenium in the future.

Automated summary

The study presents a removal route for impurity Pb in crude selenium, controlling potential oxidation and vacuum distillation process based on the Eh-pH diagram of Pb-Se-H2O and Pb-Te-H2O system. The results showed that PbSe and PbTe in crude selenium were oxidized to PbSeO3 and Pb2+, effectively preventing the volatilization of lead during vacuum distillation, leading to a high purity selenium product with low Pb content under specific conditions. This study provides a theoretical basis and method for removing impurity Pb and has potential applications in eliminating impurities from crude selenium in the future.