Somnath Sinhamahapatra

Refractories of alumina-silica system

The inorganic phases belonging to the binary alumina-silica system exhibit a plethora of excellent high temperature properties that make them useful for refractory applications. Synthesized from abundant aluminosilicate minerals, these refractories are ubiquitous in high temperature industrial applications. The refractories of alumina-silica system can be engineered to generate a range of high temperature properties by varying the Al2O3/SiO2 ratio, presence of other oxides and texture. This versatility is unique to this system and is reflected in widely varied fields of applications of these refractories. Composed predominantly of mullite and corundum phases, the non crystalline phases also play important role in determining the property and end use of these refractories. This review covers different theoretical and practical aspects of refractories of aluminosilicate system spanning 30-100% alumina. Important role of microstructure in aluminosilicate refractory has been discussed in light of phase diagram, raw materials and thermo-chemical reactions. The applications of these refractories in different areas have been discussed in detail with structure-property correlation.