Utilization of waste heat for pre-heating of anodes

• Main Authors: Grimstad, Martin, Elstad, Kim Ronny, Solheim, Asbjørn, Einarsrud, Kristian Etienne
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2020
• Subjects: Energy efficiency; Waste heat; Anode pre-heating; Grimstad; Mosjøen; Solheim
• Online Access: https://hdl.handle.net/11250/2685504; https://doi.org/10.1007/978-3-030-36408-3_108

This is the accepted manuscript. The final publication is available at: Grimstad M., Elstad K.R., Solheim A., Einarsrud K.E. (2020) Utilization of Waste Heat for Pre-heating of Anodes. In: Tomsett A. (eds) Light Metals 2020. The Minerals, Metals & Materials Series. Springer, Cham. https://doi.org/10.1007/978-3-030-36408-3_108 Carbon anodes are replaced on a regular basis in Hall–Héroult cells as they are consumed by electrochemical reactions. Upon insertion of new anodes, bath will freeze locally as a result of low bath superheat and comparatively low anode temperature, creating an insulating layer on the anode surface, thereby delaying further production. In the current work the potential for pre-heating anodes directly utilizing waste heat from off-gas and spent anode butts is investigated using a numerical model realized in COMSOL and industrial measurements at the Alcoa Mosjøen smelter. Anode core temperatures over 150 ∘ C and surface temperatures over 250 ∘ C were found when using butts as a direct heat source. Frozen bath samples from both pre-heated and regular anodes were collected and analysed using computer tomography (CT) in order to assess how various heating strategies influences frozen bath morphology. acceptedVersion