Efficient Separation and Purification Method for Recovering Valuable Elements from Bismuth Telluride Refrigeration Chip Waste

[Image: see text] Bismuth telluride and its alloys are widely utilized in thermoelectric refrigeration and power generation devices. Waste bismuth telluride-based cooling chips contain valuable elements; however, recycling processes for these materials remain underdeveloped due to their complexity. In this study, we developed a concise and efficient chemical method that does not require expensive reagents or equipment, enabling the separation and purification of tellurium, bismuth, selenium, and antimony from waste bismuth telluride-based cooling chips. Initially, the waste was leached with HCl and NaClO(3) to dissolve primary elements and recover 99.9% of selenium using hydroxylamine hydrochloride. Subsequently, Na(2)S and NaOH were employed for precipitation and leaching, resulting in a solution containing tellurium. The precipitated residue was treated with HNO(3) to oxidize antimony into insoluble SbOHN and dissolve bismuth completely. 99.8% of the bismuth telluride waste was dissolved via oxidative leaching through hydrolysis. A small amount of sodium sulfide reduced the precipitation percentage of tellurium from 11.9% to 7.5% in an alkaline solution, and the direct recovery percentage of tellurium in the form of TeO(2) exceeded 90%, while the purity of TeO(2) reached 99.9%. By adjusting the pH of the bismuth solution to 0.15, 98.9% of the bismuth was able to precipitate and be recovered as BiOCl, with the purity also reaching 99.9%. In summary, this study presents an efficient hydrometallurgical method for treating bismuth telluride waste and provides theoretical guidance for reagent dosage, demonstrating the significant potential for industrial applications.