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Utilization of waste heat for pre-heating of anodes

Abstract

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
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Category

Academic article

Language

English

Author(s)

Affiliation

  • SINTEF Industry / Metal Production and Processing
  • Norwegian University of Science and Technology
  • Alcoa Norway

Year

2020

Published in

The Minerals, Metals & Materials Series

ISSN

2367-1181

Page(s)

811 - 816

View this publication at Norwegian Research Information Repository