A method of extracting Te and bismuth oxide and recovering byproduct comprises: leaching raw materials with a Te content of ≧1.8% by utilizing a leaching system containing H 2 SO 4 , Cl − , Br − , NH 4 + and NaClO 3 , reducing leach solution with SO 2 gas by precipitation method after separating impurities from it, washing with concentrated hydrochloric acid to obtain tellurium precipitation (18), purifying to obtain Te with a purity of higher than 99.99%. The filtrate produced is used for extracting Bi 2 O 3 with a purity of higher than 99.99% when Bi content in the raw material is ≧2%. Acidic waste solution produced during the process could be returned to the leaching step for recycle.

Method of extracting Te and bismuth oxide and recovering byproducts

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 + Fe = Te + Fe .

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

PURPOSE: To recover TeO 2 with high efficiency by adjusting the pH of extracted liquid obtd. by treating anode slime with mineral acid to adjust the pH to a specified value, and adding a specified amt. of sodium sulfite to form precipitate. CONSTITUTION: Anode slime is deposited on the surface of an insoluble anode when tellurium is obtd. by electrowinning of electrolytic liquid of sodium tellurite. The anode slime is treated with mineral acid (e.g. H 2 SO 4 ) and the solid is separated from the liquid to prepare extracted liquid, and alkali (e.g. NaOH) is added to the extracted liquid to adjust the pH to 4W8. The extracted liquid is stirred while maintaining the pH, and 0.7W1.5 times weight (basing on the amt. of tellurium contained in the extracted liwuid) of sodium sulfite is added and the mixture is stirred for ca.2W3hr. The temp. at this stage is held at below ca.30°C. The liquid is then allowed to stand or filtered and generated precipitate is separated. Thus, TeO 2 having high purity is recovered at high yield. COPYRIGHT: (C)1987,JPO&Japio

Hiroshi Furumi

Papers

Method for recovering tellurium from anode slime produced by electrolysis of tellurium