Cristin-resultat-ID: 890951
Sist endret: 13. desember 2012, 10:41
NVI-rapporteringsår: 2012
Resultat
Vitenskapelig artikkel
2012

Chemical Degradation of Cathode Linings in Hall-H,roult Cells-An Autopsy Study of Three Spent Pot Linings

Bidragsytere:
  • Kati Tschøpe
  • Christian Schøning
  • Jørn Lone Rutlin og
  • Tor Grande

Tidsskrift

Metallurgical and Materials Transactions B
ISSN 1073-5615
e-ISSN 1543-1916
NVI-nivå 2

Om resultatet

Vitenskapelig artikkel
Publiseringsår: 2012
Volum: 43
Hefte: 2
Sider: 290 - 301

Importkilder

Scopus-ID: 2-s2.0-84861829099
Isi-ID: 000301778200008

Beskrivelse Beskrivelse

Tittel

Chemical Degradation of Cathode Linings in Hall-H,roult Cells-An Autopsy Study of Three Spent Pot Linings

Sammendrag

Cathode autopsies are used frequently in the aluminum industry to investigate pot failure and the degradation of the cathode lining. The materials observed in spent pot lining (SPL) has so far been assumed to reflect the sequence of layers from the cathode to the nonreacted refractory lining as present during the operation of the cell. Here, we demonstrate that the thermal gradient in the lining is reversed during cooling and that the physical appearance of the SPL is caused both by processes taking place during operation and cooling of the shutdown cell. X-ray diffraction and microscopy of the SPL from three shutdown cells revealed that sodium metal is the main component responsible for the chemical degradation of the refractory lining. Two distinct reaction fronts were identified in the three SPL showing that sodium is penetrating deeper down into the lining than the molten fluorides from the electrolyte. The mechanisms for the transport of sodium and bath components in the refractory lining are proposed based on the experimental observations. The sodium penetration is inhibited by the formation of a viscous barrier as suggested previously, but the current findings suggest that the barrier retards diffusion of O2– and F– anions rather than Na+ as proposed previously.

Bidragsytere

Kati Tschöpe

Bidragsyterens navn vises på dette resultatet som Kati Tschøpe
  • Tilknyttet:
    Forfatter
    ved Institutt for materialteknologi ved Norges teknisk-naturvitenskapelige universitet

Christian Schøning

  • Tilknyttet:
    Forfatter
    ved Metallproduksjon og prosessering ved SINTEF AS

Jørn Lone Rutlin

  • Tilknyttet:
    Forfatter
    ved Norsk Hydro ASA

Tor Grande

  • Tilknyttet:
    Forfatter
    ved Institutt for materialteknologi ved Norges teknisk-naturvitenskapelige universitet
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