Cordierite Raw Materials
Introduction
Cordierite Raw Materials, The basic raw materals 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 aluminium cyclosilicate. Cordierite has excellent thermal properties. On the air, however, leads to its transformation into a muscovite, biotite and chlorite. An alternative to the 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 at 1435°C is produced by decay of magnesium and kaolinitic materials during firing near 1400°C.
Cordierite is commonly used for production of special refractory ceramics (burning utilities, etc.) and electro technical 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 temperature 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.
Features
· Good thermal shock resistance.
· Low thermal expansion.
· Low thermal conductivity.
· High dielectric strength.
Fired Temperature (°C) | Thermal Expansion Coefficient(x10-6/°C) |
1250 | 3.10 |
1300 | 3.16 |
1350 | 4.52 |
1400 | 2.98 |
Sizes
Section Sand Size: 1-0mm 3-1mm 5-3mm 8-5mm
Fine Powder Size: 200Mesh 325Mesh
Chemical & Physical Index
Property | Unit | Non-Porous Cordierite | Porous Cordierite | |
DIN EN 60 672 Identification | C410 | C511 | ||
Composition | % | MgO•SiO2•Al | MgO•SiO2•Al | |
Density | g/cm3 | > 2.1 | > 1.9 | |
Bulk Porosity | % | <0.5 | <20 | |
Colour | yellow, brown, white | yellow, brown, white | ||
Mechanical Characteristics at 20 °C | ||||
Hardness on Vickers’ Scale HV10 | MPa | - | - | |
Compressive Strength | MPa | > 300 | > 200 | |
Flexural Strength | MPa | > 60 | > 25 | |
Elastic Modulus | GPa | - | - | |
Thermal Characteristics | ||||
Max. Operating Temperature | °C | 1,000 | 1,200 | |
Specific Warmth at 20 °C | J K−1 kg−1 | 800-1,200 | 750-850 | |
Thermal Conductivity at 100 °C | W.m-1.K-1 | 1.5-2.5 | 1.3-1.8 | |
Expansion Coefficient from 20 to 1,000 °C | 10-6/K-1 | 2-4.5 | 4-6 | |
Electrical Characteristics | ||||
Electrical Resistivity | at 20 °C | Ω.m | > 1010 | - |
at 600 °C | > 103 | > 103 | ||
Dielectric Strength | kV/mm | > 10 | - | |
Application :
Taking advantage of its good resistance to thermal shocks, cordierite is used in the field of electrical insulation, burner pipes or kiln furniture in the ceramics industry. This refractory material is also used as raw material in stoneware oven dishes or glass-ceramic cooker hobs.
Package
1MT Big Bag