A recycling process for thermoelectric devices developed with the support of statistical entropy analysis

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Resources, Conservation and Recycling, Volume 159
Thermoelectric devices (TEDs) are solid-state devices capable of converting a temperature gradient into electric power. Due to their robust physical composition, the importance of TEDs has increased recently as their applications have broadened from the aerospace industry to the recovery of waste energy from heat sources. As a consequence, an increase in their consumption and future disposal is expected. Nowadays, there is no recycling process designed for TEDs, thus representing an open-loop stream of end-of-life products, which results in the loss of valuable materials. This work aims to address this future problem. Hereby, commercial thermoelectric devices were mechanically processed and characterised. With the experimental results thus produced, statistical entropy analysis was performed to propose a suitable recycling process. Three different mechanical processing systems are compared by their liberation and concentration efficiencies. Based on the final values of statistical entropy, a final mechanical processing system is proposed consisting of grinding in a ring mill, followed by sieving with 3350 µm and 1000 µm openings. Furthermore, the characterization results suggest the possible addition of a dense media separation step to enrich the different material present in the fraction <1000 µm. The recommended system achieves a significant entropy reduction of Cu and separation of plastics from ceramics and semiconductors in only four steps. The final recoveries are TED components that may be suitable for metal refinement by other metallurgical means.
Circular economy, Recycling, Statistical entropy analysis, Thermoelectric devices
Other note
Velázquez-Martinez, O, Kontomichalou, A, Santasalo-Aarnio, A, Reuter, M, Karttunen, A J, Karppinen, M & Serna-Guerrero, R 2020, ' A recycling process for thermoelectric devices developed with the support of statistical entropy analysis ', Resources, Conservation and Recycling, vol. 159, 104843 . https://doi.org/10.1016/j.resconrec.2020.104843