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+>.