A method for separating and purifying selenium and tellurium from a mixture of selenium and tellurium

Abstract

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.

Description

technical field [0001] The invention relates to the technical field of hydrometallurgy, in particular to a method for separating and purifying selenium and tellurium from a selenium-tellurium mixture. Background technique [0002] In the process of copper anode slime treatment, the selenium in the anode slime exists in the chlorinated liquid after chlorination, and the chlorinated liquid is reduced by sulfur dioxide in one stage to produce crude selenium, and the reduced liquid in the first stage is reduced to produce crude selenium in the second stage. A selenium-tellurium mixture containing about 20-30% selenium, 15-25% tellurium, and 20-30% copper is produced. The crude selenium produced by the first-stage reduction is refined by vacuum melting to produce selenium products, while for the second-stage reduction product For the selenium-tellurium mixture, there is no mature process for the separation and purification of selenium and tellurium, but the existing technology ha...

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Problems solved by technology

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method for separating and purifying selenium and tellurium from a mixture of selenium and tellurium, aiming to solve the problems in the prior art that the extraction rate of selenium and tellurium is low, the mixture of selenium and tellurium is difficult to separate, etc.

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