Method for extracting tellurium dioxide from anode slime produced through tellurium electro-deposition

Abstract

The invention discloses a method for extracting tellurium dioxide from anode slime produced through tellurium electro-deposition. The method comprises the following steps that 1, the anode slime is put into a reaction kettle, water and sodium hydroxide are added, heating and mixing are performed for two hours, and filter pressing is performed to obtain filter residues, namely the tellurium dioxide; 2, the filter residues are put into the reaction kettle, water is added, a PH value is regulated to be 1.0-1.5 by using sulfuric acid, heating is performed to reach 85 DEG C, stirring is performed for two hours, and filter pressing is performed to obtain filtrate; 3, the filtrate is added into the reaction kettle, and iron powder is added and stirred for three hours; 4, sodium hydroxide is added after the solution is clarified and transparent, the PH value is regulated to be 7.0, then sodium hydroxide with the tellurium metal content 70% is added and stirred for an hour, filter pressing is performed to obtain a sodium tellurite solution, the PH value is regulated to be 5-5.5 by using sulfuric acid, and filter pressing is performed to obtain tellurium dioxide. In the step 3, the amount of the iron powder is determined according to the tellurium content in the filtrate and meets the requirements of a reaction equation: Te<6+> + Fe<0>= Te<4+> + Fe<2+>.

Description

technical field [0001] The invention relates to a method for extracting tellurium dioxide, in particular to a method for extracting tellurium dioxide from anode slime produced by tellurium electrowinning. Background technique [0002] The anode slime produced during the production of refined tellurium by electrowinning contains a large amount of tellurium trioxide and a small amount of tellurium dioxide, which can be utilized in advance. [0003] At present, the method of extracting tellurium dioxide from the anode slime produced in the process of producing refined tellurium by electrowinning is mainly: using high-concentration sulfuric acid to convert tellurium trioxide into tellurium sulfate solution, and then adding a large amount of sodium chloride. Adding sodium sulfite under chemical conditions reduces hexavalent tellurium ions to tetravalent tellurium ions, and then adjusts the pH value with alkali to extract tellurium in the form of tellurium dioxide. The disadvanta...

AI Technical Summary

Problems solved by technology

The disadvantage of using this method is that the conversion rate of tetravalent tellurium is low, and the conversion rate is generally about 60%. A large amount of tellurium remains in the slag in the form of zero-valent tellurium and hexavalent tellurium, and high acid and high chlorination are used, and the working conditions are harsh. , equipment corrosion, high cost