Chemical Degradation of Cathode Linings in Hall-Héroult Cells—An Autopsy Study of Three Spent Pot Linings

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