Targeted recovery of metals from thermoelectric generators (TEGs) using chloride brines and ultrasound

Zante, G., Daskalopoulou, E., Elgar, C. E., Marin Rivera, R., Hartley, J., Simpson, K., Tuley, R., Kettle, J. and Abbott, A. P. (2023) Targeted recovery of metals from thermoelectric generators (TEGs) using chloride brines and ultrasound. RSC Sustainability, 1(4), pp. 1025-1034. (doi: 10.1039/D3SU00087G)

Abstract

Recovery of elemental copper, bismuth, tellurium, antimony and tin from thermoelectric generators (TEGs) is vital to recover the high content of critical metals and potential risk of environmental pollution as a result of incorrect disposal of TEGs and to enable the circular economy. In this work, aqueous choline chloride and calcium chloride hexahydrate brines were characterised and used in combination with copper(II) as an oxidising agent to leach copper and tin from TEGs. This permitted the Bi2−xSbxTe3 legs to be readily separated from the ceramic substrates by filtration. It was shown that at low chloride content, surface passivation and solubility of the oxidised species were the limiting factors towards oxidation, whereas solvent viscosity (mass transport) was the limiting factor at high chloride content. The copper(II) species formed in the different brines were determined via UV-vis spectroscopy. The redox potentials of the oxidising species were found to be significantly altered by choline chloride content, but not so much by calcium chloride hexahydrate content, suggesting variation in chloride activity within the different brines. The developed approach has been shown to be a viable and scalable method to recover high value critical metals from e-waste containing TEGs.

• Item Type: Articles
• Additional Information: This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement number 101026159. The authors would also like to thank the Faraday Institution (Faraday Institution grant code FIRG027, project website https://relib.org.uk), and the UKRI Interdisciplinary Circular Economy Centre for Technology Metals, Met4Tech project (EP/V011855/1) for funding this work.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kettle, Professor Jeff
• Authors: Zante, G., Daskalopoulou, E., Elgar, C. E., Marin Rivera, R., Hartley, J., Simpson, K., Tuley, R., Kettle, J., and Abbott, A. P.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: RSC Sustainability
• Publisher: Royal Society of Chemistry
• ISSN: 2753-8125
• ISSN (Online): 2753-8125
• Published Online: 30 May 2023
• Copyright Holders: Copyright © 2023 Royal Society of Chemistry
• First Published: First published in RSC Sustainablity 1(4):1025-1034
• Publisher Policy: Reproduced under a Creative Commons license