High Temperature Creep Behaviour of Carbon-Based Cathode Material for Aluminum Electrolysis

The creep strain of the semi-graphitic commercial cathode material used for aluminum production was measured on solid cylinder sample. Experimental results were obtained using a modified Rapoport equipment for the cathode material during aluminum electrolysis with a cryolite mole ratio (NaF/AlF3) of 2.5 and at a temperature of 950 °C under different stress levels. The coincident method proposed previously was applied to model the creep strain of carbon-based cathode material. The test data were processed, and the creep characteristics of the cathode material were determined based on Graham creep equation. A relationship between creep coefficients and stress has been developed. Then, the creep characteristics of the cathode material were obtained by finite element numerical simulations. The model results were in accordance with the experimental ones. This work will contribute to controlling the quality of the carbon cathode and improving the cell design.