Recycling of enamelled copper wire from end-of-life electric motor via room temperature methanolysis

Widijatmoko, Samuel D., Cui, Zhehao (john), Agalit, Hassan, Li, Yongliang and Leeke, Gary A. (2024) Recycling of enamelled copper wire from end-of-life electric motor via room temperature methanolysis. Resources, Environment and Sustainability, 15. ISSN 2666-9161

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Abstract

Polyester enamelled copper wire plays an important role in the manufacturing of electric motors. In line with the electrification of transport, the demand for electric motors and the future waste generated from their end-of-life cannot be ignored. The waste from the polyester enamelled copper wire is expected to increase steadily. Methods proposed by researchers are mainly focused on thermal treatment to either pyrolyse or burn off the polyester enamel. However, thermal treatments fail to consider the potential risk of air pollution and to recover the polyester enamel. In this manuscript, we propose two-stage processes comprised of methanol washing and room temperature methanolysis with dichloromethane as co-solvent and K 2CO 3 as catalyst to delaminate multilayered type enamelled copper wire. The methanol washing recovers polyvinyl butyral as it is, via dissolution. Whereas the methanolysis products are dimethyl terephthalate (DMT) and dimethyl isophthalate (DMI) which are precursors to the polyester and could be used to make new polyester. At room temperature, the parameters of solid to liquid, DCM to methanol, and K 2CO 3 to Cu wire ratio, of 500 g/L, 1.00 mol/mol, and 0.10 wt%, respectively, allow complete removal of polyester enamel in 24 h. The methanolysis parameters described manage to give a modest DMT and DMI yield of 86.0% and 92.2%, respectively. The reaction time can be sped up by increasing the temperature by 10 °C, leading to complete depolymerisation in 4 h. Compared to thermal treatment, the proposed method requires 80.7% lower energy with the products contained within the solution.

Item Type:	Article
Official URL:	https://www.sciencedirect.com/journal/resources-en...
Additional Information:	© 2023 The Author(s)
Divisions:	Grantham Research Institute
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences T Technology > TP Chemical technology
Date Deposited:	11 Jan 2024 12:24
Last Modified:	21 Mar 2024 10:36
URI:	http://eprints.lse.ac.uk/id/eprint/121346

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