CHEMICAL DEGRADATION MAP FOR SODIUM ATTACK IN REFRACTORY LININGS

摘要

Here we show by autopsies of spent pot linings that the degradation of the refractory lining in aluminum reduction cells is governed by sodium transport into the lining. The chemical reactions caused by sodium infiltration are qualitatively explained by the construction of a chemical degradation map. The degradation map corresponds to a predominance phase diagram showing the stable compounds present as a function of SiO_2/Al_2O_3 ratio in the refractory lining and the amount of sodium infiltrated in the lining. We demonstrate that the degradation map is a useful tool for the evaluation of autopsies of spent pot linings and the prediction of the mineralogical composition of the spent pot lining.