Sillimanite (Chemical Formula: Al2SiO5) is the alumino-silicate mineral, which shares allotropy with Kyanite and Andalusite. Sillimanite is rough, abrasive and scores 6-7 (Moh’s scale of hardness). Fibrolite is the common variety of Sillimanite and it is named after its fibrous structure when seen by the naked eye.
The volume porosity of Sillimanite grains rarely exceeds 6% after heating and it decreases further, when heated for a long time. This compactness makes it perfect for applications where abrasion and corrosion may occur. Sillimanite has many valuable properties such as low thermal conductivity (9.10 W/m/K), high specific heat capacity, bad conductor of electricity, high melting point, neutral reaction and can withstand temperatures up to 1550 o C after which it decomposes to mullite. Sillimanite is non inflammable and non-explosive, which is why it is used in production of refractory products.
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|Note: Sillimanite is a natural product and as such slight variations in the chemical analysis and size distribution should be expected. Special contracts covering guarantees other than those specified can be negotiated.|
Industrial Applications of Sillimanite