Silicon carbide brick

Although many different types of investigations in the area of alkali corrosion of refractories have been performed, there still appears to be doubt regarding the best method for testing. In addition, there are few comparative studies in the literature showing the differences in alkali corrosion of the different alumino-silica refractories. Studies concerning silicon carbide bricks exposed to alkalies are practically nonexistent. 

Refractory bricks and other materials are used, both with and without a lining between the steel and bricks, to enclose reaction chambers. Depending on the conditions to be withstood, the products used include basic and neutral materials with high silicon carbide bricks. The structure of a chemically resistant brick lining is shown schematically in Figure 20.80. 

Silicon carbide brick are suitable for high temperature applications. They are also a high abrasion resistant brick. These brick are made to fireclay sizes. 

According to Konopicky (1957), the expansion joints should, as a rule of thumb, be designed to absorb half the thermal expansion that develops up to the service temperature of the refractory lining. Approximate values to be adopted are 0.5% for fireclay and silicon carbide brick, and 1.2% for magnesite-chrome and dolomite brick. The expansion joints are filled with cardboard, which burns away when the kiln is heated, leaving the joints clear. In general, it is more favourable to provide a larger number of narrower expansion joints than a smaller number of wider ones. 

Ceramic liners vary in thickness from about 6 to 25 millimeters, depending on the type of installation and the severity of service. In some large-scale cyclones, silicon carbide bricks have been installed. Most ceramics have a density of about 3800 kg/m (240 Ib/ft ) and can withstand temperatures up to about 1500°C. 

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