Aging of Insulating Linings in Aluminium Electrolysis Cells

Dimensional stability of materials used in aluminium electrolysis cells are important for stable cell operation. The observed compression of insulating linings from autopsies of industrial cells are in many cases much higher than would be expected from laboratory creep tests of the corresponding materials. Creep in compression of three commercial insulating materials for aluminium electrolysis cells, produced from diatomite, perlite and calcium silicate, respectively, has been studied. The creep rates were measured versus temperature and load on as received materials, after additional heat treatment, and materials contaminated with KF and NaF. Refiring the as received materials resulted in a substantial decrease in the creep rate.