Method of separating and purifying Se and Te from Se/Te mixture

The invention discloses a method of separating and purifying Se and Te from a Se/Te mixture, which includes the following steps: 1) Se/Te mixture leaching: firstly slurrying the Se/Te mixture and then adding hydrochloric acid and an oxidant into slurry to perform water-dissolving and chlorination leaching, and filtering a leached product, wherein filter residues are fed back to selenium reduction and a filtrate is used for later use; 2) primary reduction of the filtrate: heating the filtrate with vapor, adding SO2 to perform the primary reduction of the filtrate, and after a certain time, filtering the reduced filtrate to generate selenium powder and a primary reduced solution; and 3) secondary reduction of the primary reduced solution: heating the primary reduced solution with vapor, feeding SO2 to perform the secondary reduction, and after a certain time, filtering the primary reduced solution to obtain crude tellurium and a secondary reduced solution. The method is carried out in a manner of leaching the Se/Te mixture and reducing the leachate in sections, so that the grade of selenium reaches 95-99% and the grade of tellurium reaches 90-95% after reduction, thereby greatly increasing the purities of Se and Te after recycling.