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Effect of composition and temperature on current efficiency for aluminium electrolysis from cryolite-based molten alumina electrolytes

Abstract

The current efficiency (CE) for aluminium electrolysis in modern cells can be as high as 96 %. The main reason for loss in current efficiency is the so-called back reaction between dissolved metal and the anode product of CO2. Decreasing temperature of the cell may give higher current efficiency. However, low superheat may cause solidification of melt. A laboratory cell to determine the current efficiency was recently modified to obtain more reliable results. Electrolysis was performed at constant current density and the current efficiency was determined from the weight of deposited aluminium. Effects of electrolyte composition by addition of LiF and temperature were studied. The loss in current efficiency is strongly related to the content of dissolved metal in the electrolyte. The effect of LiF addition on the current efficiency was discussed in this study.
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Category

Academic article

Language

English

Author(s)

Affiliation

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

Year

2017

Published in

ECS Transactions

ISSN

1938-5862

Volume

77

Issue

11

Page(s)

997 - 1002

View this publication at Norwegian Research Information Repository