Andalusite
Andalusite is a naturally occurring alumino-silicate mineral with a high alumina content. Andalusite is a precious raw material in the production of refractories and foundry castings.
Key figures
#1
World’s leading producer of alumino-silicates for the refractory industry.
60%
Up to 60% alumina content
1,200°C
Temperature at which andalusite converts to mullite
Ideal for refractories
Andalusite is a naturally occurring alumino-silicate mineral commonly found in metamorphic rocks. It is a high-purity mineral composed of prismatic and anhydrous crystals.
Containing up to 60% alumina, andalusite transforms into mullite at low temperatures of between 1,200°C and 1,550°C. This refractory mineral offers properties such as high resistance to degradation in extreme temperatures and harsh operating conditions as well as resistance to mechanical failure and corrosion.
Andalusite is prized for the production of high-quality acid refractory products requiring high-alumina content.
In the investment casting market, it is used as well for the production of sand moulds and cores for steel and iron casting.
Andalusite is an alumino-silicate with the chemical formula
Physical properties
- Outstanding creep resistance
- Very good refractoriness under load (RUL)
- Low thermal expansion
- Low thermal conductivity
- Good chemical stability
- Excellent thermo-mechanical stability
- Excellent thermal shock resistance
- Oxidation resistance
Global benchmark
Imerys mines high-quality andalusite from deposits in Brittany (France) and South Africa serving customers worldwide. Imerys andalusites are recognized as the global benchmark for high-temperature industries.
Further upstream, our Technology Centers based in Lyon (France) and Tianjin (China) feature an extensive range of minerals processing, testing and analysis tools focused on high resistance materials.
Robust solution for high-temperature industries
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Imerys andalusite-based refractory solutions are ideal for fired and unfired refractories (Monolithics and bricks) owing to their outstanding creep and high thermal shock resistance as well as resistance to chemical attack, slag and metal penetration.
In modern foundry casting, andalusite sands are ideal solutions for steel and iron casting where they prevent veining and finning in the final product due to their low thermal expansion and high refractoriness.
Andalusite is an excellent natural source of alumina for the production of kiln furniture and ceramic supports.
Harnessing our wide portfolio of andalusite-based products, Imerys will continue to create value for its customers through high-performance, inventive and differentiating solutions.
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