Cordierite Raw Materials

Cordierite Raw Materials, The basic raw materials for cordierite refractory products are cordierite fireclay and special MgO-substrates which contribute to the cordierite formation (2MgO·2 Al₂O₃·5SiO₂) at the point of an Al₂O₃ and SiO₂ surplus, in particular in the bonding matrix. Usually, shaping is done by hydraulic dry pressing, in particular for the manufacture of large-shaped kiln furnace covers.

Nature cordierite is a magnesium-iron aluminum cyclosilicate. Cordierite has excellent thermal properties. On the air, however, leads to its transformation into muscovite, biotite, and chlorite. An alternative to natural cordierite is cordierite ceramics - synthetic cordierite. Material containing over 10% of MgO and over 34% of Al₂O₃ is typical for its low thermal expansion coefficient, hardness, and stability. Stable α-cordierite with a melting point of 1435 °C is produced by the decay of magnesium and kaolinitic materials during firing near 1400 °C.

Cordierite is commonly used for the production of special refractory ceramics (burning utilities, etc.) and electrotechnical applications (electrical insulators, contactors, heaters carriers, etc.) due to its low thermal expansion coefficient and high resistance to sudden temperature changes. A suitable composition of cordierite with other types of refractory grog can get good thermally stable materials appropriate for higher temperatures than the own melting point of cordierite pottery. Cordierte-rich products are characterized by their excellent thermal shock resistance due to their very low reversible heat expansion. Their main area of use in kiln cars and as kiln furniture for ceramic firing furnaces relies on the latter.