Investigation of low-cost, simple recycling process of waste thermoelectric modules using chemical reduction

Abstract

A low-cost and simple recycling process of waste thermoelectric modules has been investigated using chemical reduction methods. The recycling is separated by two processes, such as dissolving and reduction. When the waste thermoelectric chips are immersed into a high concentration of HNO3 aqueous solution at 100 °C, oxide powders, e.g., TeO2 and Sb 2O3, are precipitated in the Bi3+ and HTeO 2+ ions contained solution. By employing a reduction process with the ions contained solutions, Bi2Te3 nanoparticles are successfully synthesized. Due to high reduction potential of HTeO2+ to Te, Te elements are initially formed and subsequently Bi2Te3 nanoparticles are formed. The average particle size of Bi2Te3 was calculated to be 25 nm with homogeneous size distribution. On the other hand, when the precipitated powders reduced by hydrazine, Sb2O3 and Te nanoparticles are synthesized because of higher reduction potentials of TeO2 to Te. After the washing step, the Sb2O3 are clearly removed, results in Te nanoparticles. Copyright © 2005 KCSNET.