Aluminum Reduction Technology: Joint Session on Cell Lining Materials
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Mark Dorreen, Light Metals Research Centre, The University of Auckland

Tuesday 8:30 AM
February 28, 2017
Room: 2
Location: San Diego Convention Ctr

Session Chair: Stephan Broek, Hatch


8:30 AM Introductory Comments

8:35 AM  
Chemical Stability of Thermal Insulating Materials in Sodium Vapour Environment: Raymond Luneng1; Søren N. Bertel2; Jørgen Mikkelsen2; Arne P. Ratvik3; Tor Grande1; 1NTNU; 2Skamol A/S; 3SINTEF Materials and Chemistry
    The most typical thermal insulating materials used in the cathode lining in aluminium electrolysis cells are moler, calcium silicate or vermiculite based materials. The thermal insulation is important for the overall thermal and dimensional stability of the cell. A refractory layer protects the thermal insulation layer, but recently it has become important to investigate the chemical stability of these thermal insulating materials. Here we report on the chemical degradation, caused by sodium vapour, of thermal insulating materials in a laboratory test resembling the environments in the cathode lining. The exposed materials were investigated with respect to changes in the microstructure, chemical and mineralogical composition by a combination of optical and electronic microscopy and powder X-ray diffraction. These investigations revealed different reaction patterns for the three materials and the formation of new mineralogical phases were identified. Finally, these findings were compared with chemical reactions with sodium based on computational thermodynamics.