Estimating perfluorocarbon emission factors for industrial rare earth metal electrolysis

Cai, Bofeng, Liu, Helin, Kou, Fan, Yang, Youming, Yao, Bo, Chen, Xiping, Wong, David S., Zhang, Lizhi, Li, Jianzhong, Kuang, Guochun, Chen, Liqu, Zhang, Jinwen, Guan, Dabo and Shan, Yuli (2018) Estimating perfluorocarbon emission factors for industrial rare earth metal electrolysis. Resources, Conservation and Recycling, 136. pp. 315-323. ISSN 0921-3449

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Rare earth (RE) metals have been widely applied in new materials, leading to their drastic production increase in the last three decades. In the production process featured by the molten-fluoride electrolysis technology, perfluorocarbon (PFC) emissions are significant and therefore deserve full accounting in greenhouse gas (GHG) emission inventories. Yet, in the ‘2006 IPCC Guidelines for National Greenhouse Gas Inventories’, no method currently exists to account for PFC emissions from rare earth metal production. This research aims to determine emission factors for industrial rare earth metals production through on-site monitoring and lab analysis of PFC concentrations in the exhaust gases from rare earth metal electrolysis. Continuous FTIR measurements and time-integrated samples (analysed off-site by high-precision Medusa GC–MS) were conducted over 24–60 h periods from three rare earth companies in China, covering production of multiple rare earth metals/alloys including Pr-Nd, La and Dy-Fe. The study confirmed that PFC emissions are generated during electrolysis, typically in the form of CF4 (∼90% wt of detected PFCs), C2F6 (∼10%) and C3F8 (<1%); trace levels of c-C4F8 and C4F10 were also detected. In general, PFC emission factors vary with rare earth metal produced and from one facility to another, ranging from 26.66 to 109.43 g/t-RE for CF4 emissions, 0.26 to 10.95 g/t-RE for C2F6, and 0.03 to 0.27 g/t-RE for C3F8. Converted to 211.60 to 847.41 kg CO2-e/t-RE for total PFCs, this emissions intensity for rare earths electrolysis is of lower (for most RE production) or similar (Dy-Fe production) level of magnitude to industrial aluminium electrolysis.

Item Type: Article
Uncontrolled Keywords: pfc,greenhouse gas,emission factor,rare earth metal,electrolysis,sdg 13 - climate action ,/dk/atira/pure/sustainabledevelopmentgoals/climate_action
Faculty \ School: Faculty of Social Sciences > School of Global Development (formerly School of International Development)
Faculty of Science > School of Environmental Sciences
UEA Research Groups: Faculty of Social Sciences > Research Centres > Water Security Research Centre
Depositing User: LivePure Connector
Date Deposited: 25 Jul 2018 14:05
Last Modified: 22 Oct 2022 03:59
DOI: 10.1016/j.resconrec.2018.04.018


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