Carbon Side Lining Causes for Decay

According to the HaU-Heroult reduction cell heat balance [136, 137], approximately 35 % of heat is transferred away through the sides (Fig. 2.6). 

Consequently, the requirements for the side Uning materials of a reduction cell are 

Carbon anthracite side-wall blocks were used for a long time. The reactimi between air oxygen and the carbon starts begiiming at 400-500 °C at 900 °C, the reaction rate is considerable. Additives to the material of carbon side-wall blocks make oxidation slower. The carbon side lining deteriorates due to oxygen in the upper part (Fig. 2.63) or in the lower part from the side of the shell (in case of air leakage through busbar windows). 

Bath and aluminium circulation enhance the wear of carbon side-wall blocks due to erosion, so the combination of chemical attack and erosion takes place. The biggest wear is at the border of bath and aluminium, as the formation of aluminium carbide is enhanced in the presence of cryolite, which acts as a solvent for oxide layers and aluminium. Chain reactions (2.27, 2.28, 2.29 and 2.30) are in Sect. 2.3. 

The producers of carbon materials offered several decisions to increase the properties of carbon side lining (Table 2.12). There were variants of anthracite- 

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