Dehydrofluorination behavior of poly(vinylidene fluoride) during thermal treatment using calcium carbonate

• Published in: Thermochimica acta 2021-08, Vol.702, p.178977, Article 178977
• Main Authors: Tanaka, Futoshi, Gungaajav, Lkhagvasuren, Terakado, Osamu, Kuzuhara, Shunsuke, Kasuya, Ryo
• Format: Article
• Language: English
• Subjects: Alkaline earth carbonate; Fluorine; Lithium-ion batteries; PVDF; Thermal decomposition
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2021.178977

•Thermal pretreatment was applied to recover various metals from spent lithium ion batteries (LIBs).•Thermal treatment of spent LIBs emits toxic hydrogen fluoride (HF) from electrolyte and binders.•Thermal dehydrofluorination of representative binder, poly(vinylidene fluorides) (PVDF), was studied.•Calcium carbonate (CaCO3) addition mostly inhibited HF emission from PVDF. Various fluorine compounds types, such as electrolytes and binders, are present in lithium-ion batteries (LIBs). The novel pyrometallurgical process is applicable for metal recovery from spent LIBs; however, it results in the emission of toxic fluorides such as hydrogen fluoride (HF). For the safe treatment of spent LIBs, we investigated HF emission behavior during thermal treatment of poly(vinylidene difluoride) (PVDF) as the binder model. To suppress the emission of HF, we also examined the effect of calcium carbonate (CaCO3) addition. It was found that HF emission was suppressed from 72% of total F for pure PVDF to 0.8% through CaCO3 addition. Fluorine was fixed as stable calcium fluoride.