Nitrous Oxide Emissions: A Long-Neglected Challenge in the Aluminum Electrolysis Industry

Le résumé fourni par la source

Greenhouse gas emissions (GGE) have crucial effects on the global climate. Although prior research on GGE in the aluminum electrolysis industry (AEI) focused on carbon dioxide (CO 2 ) and perfluorocarbon (PFC) emissions, we have discovered significant nitrous oxide (N 2 O) emissions from this sector, which has been overlooked until now. In this work, we found that N 2 O had a CO 2 equivalent (CO 2eq ) emission factor twice that of CO 2 or PFCs. We also identified a significant linear relationship between the N 2 O emission factor and the product of the electrolysis cell number, the anode effect coefficient, and the duration. Based on the above results, we estimated that global N 2 O emissions from the AEI reached 65.1 ± 6.4 Mt of CO 2eq /year in 2018. The newly discovered N 2 O emissions constituted 27.4–52.2% of total GGE in the AEI and 15.7–65.1% of existing industrial N 2 O emissions. These findings highlighted that the AEI was a long-neglected source of N 2 O emissions. The N element content control in carbon anodes may be an effective measure to reduce N 2 O emissions during the processing of the anode effect. Additionally, the molten salt electrolysis process for production of metals such as sodium, magnesium, and lithium may also be a potential source of N 2 O emissions and is necessary to further investigate N 2 O reduction technologies.

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