ИСТИНА

The barrier refractory materials against the penetration of liquid aluminum and cryolite in the lining of the reduction cell have been used for many years. The tested barrier materials include alumina, carbon ramming paste, red brick, silica brick, aluminous brick, castable low-cement slabs, flat glass, steel sheets, etc. The penetration of cryolite and sodium to the refractory layer often results in appearance of the “lens” of reactants under the carbon bottom blocks. The “lens” will cause bending strains in the carbon cathode blocks, that may lead to cracking. The graphite foil is a promising candidate to be a barrier material against the penetration of molten aluminum and cryolite. The graphite foil has a unique structure that results in unique properties. Molten aluminum does not wet graphite foil. The gas permeability of the graphite foil is extremely low due to high tortuosity of pores. Industrial testing shows, that graphite foil in the lining of the reduction cell acts as a semi-transparent barrier, and the height of the lens under the foil decreases considerably.