Anode reaction in aluminium electrolysis prior to and during anode effect

Komin Shu, Jomar Thonstad

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Citations (Scopus)

Abstract

A laboratory study was conducted on the anode reaction in aluminium electrolysis prior to and during anode effect at voltages up to 12 V. The experimental methods used were cyclic voltammetry and gas chromatography, and the contents of AlF 3, CaF 2 and Al 2O 3 were varied. Three voltammetric peaks at around 2.2 V, 2.6 V and 4.3 V were observed in all low-alumina melts, except in a highly acidic melt. An additional peak at around 3.3 V was observed in Na 3AlF 6 and Na 3AlF 6 - 5 wt% CaF 2 melts. The peak currents observed in low-alumina melts were all low (< 80 mA cm -2). The peak currents of the first two peaks (at around 2.2 V and 2.6 V) increased sharply by the addition of alumina to the melts. CO was the dominant oxygen-containing gas in low-alumina melts. CO 2 was only found at low potentials (< 4 V). CF 4 generation was detected at potentials above 2.8 V. The rate of CF 4 generation was similar in the various melts, and it was in all cases low (< 40 mA cm -2). It has been shown elsewhere that alumina depletion precedes a potential shift in the positive direction, to reach the potential region for generation of CF 4. This is accompanied by a sudden drop in current, marking the onset of the anode effect.

Original languageEnglish
Title of host publicationTMS Light Metals
EditorsP.N. Crepeau
Pages343-349
Number of pages7
Publication statusPublished - 2003 Dec 1
Externally publishedYes
EventLight Metals 2003: Proceedings of the technical sessions presented by the TMS Aluminium Committee at the 132nd TMS Annual Meetings - San Diego, CA, United States
Duration: 2003 Mar 22003 Mar 6

Publication series

NameTMS Light Metals

Other

OtherLight Metals 2003: Proceedings of the technical sessions presented by the TMS Aluminium Committee at the 132nd TMS Annual Meetings
Country/TerritoryUnited States
CitySan Diego, CA
Period03/3/203/3/6

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Metals and Alloys
  • Materials Chemistry

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