Preparation of high pure tellurium from raw tellurium containing Cu and Se by chemical method

High pure tellurium was prepared from raw tellurium containing copper and selenium by chemical method containing oxidation with concentrated nitric acid, leaching with hydrochloric acid, reducing with sulfur dioxide and treating in hydrogen atmosphere at high temperature. Removal ratio of Cu in raw tellurium reaches 99% after raw tellurium is oxidized and leached with HNO3(69%) under the following conditions: 0.96 times stoichiometric quantity of concentrated nitric acid, 4:1 of ratio of liquid to solid, 20 °C of reaction temperature and 30 min of reaction time. Leaching ratio of Te reaches 99% after Te is leached with hydrochloric acid under the following conditions: 1.67 times stoichiometric quantity of hydrochloric acid, 4:1 of ratio of liquid to solid, 20 °C of reaction temperature and 30 min of reaction time. Tellurium powder(99.95%) is obtained when Te(IV) in leachate is reduced with sulfur dioxide. The purity of tellurium increases from 99.954% to 99.999 6% after tellurium(99.95%) is treated in hydrogen atmosphere at 723.15 K for 30 min.