Features of Using Modified Carbon-Graphite Lining Materials in Aluminum Electrolyzers.

Penetration of sodium into carbon-graphite material (CGM) specimens previously modified with lithium is studied. Sodium diffusion coefficients are calculated after treating CGM with lithium vapor and values are determined for activation energy of diffusion under different conditions. The kinetic dependences obtained make it possible to determine the sodium diffusion mechanism in modified CGM. The efficiency is demonstrated of preliminary treatment with lithium vapor that makes it possible to prevent aluminum electrolyzer cathode lining surface layer breakdown during operation. The tests on CGM specimens performed make it possible to create prerequisites for developing technology for hearth surface protection from sodium penetration during electrolysis in molten cryolite-alumina. [ABSTRACT FROM AUTHOR]