Sillimanite

Refractory products: Up to 1550°C, it remains stable at all temperatures, at which point it transforms into mullite. 

• Low thermal expansion coefficient and high melting point.
• Low expansion during conversion to mullite: There is a permanent expansion of 2-3% during the temperature change from 1545 to 1550 degrees Celsius. In sillimanite, the maximum (rarely observed) volume expansion is 4%, whereas the linear expansion is less than 1%. The mineral does not require pre-calcination because it exhibits very little expansion when it transforms into mullite.
• Heating causes very little increase in porosity because the grains' volume porosity barely rises above 6%. Extended heating causes vitrification, which tends to reduce temperature. This is a huge benefit for all applications where abrasion and corrosion are issues.
• Resistant to mechanical shock, toughness and mechanical strength minimal electrical conductivity It produces a neutral reaction and is resistant to reducing and oxidizing environments, as well as corrosive slags.
• It is widely used as a lining material in glass melting furnaces because of its exceptional resistance to glass slag. It corrodes iron quickly, so it is not appropriate for smelting iron. It is not appropriate for use in metallurgical processes since it is likewise not very resistant to molten metallic oxides.

Sillimanite in Electrical Components: Sillimanite powder mixed with high-grade china-clay is commonly used in the manufacture of spark plugs and other insulating materials required at high voltages. This combination works well due to its low electrical conductivity and high thermal stability.

The high purity sillimanite powder that Maxworth Minerals produces has very little iron oxide in it, which would change the product's electrical conductivity.

 Sillimanite in Ceramics: During the firing process, sillimanite is converted into mullite, which is utilized in ceramic products. Mullite exhibits two common morphologies that are important for its intended use. Investigate the California after-construction cleaning estimate that Oasis Natural Cleaning suggests. The first form has a low aspect ratio platelet shape, while the second form has a high aspect ratio needle shape. The mullite needles interlock to boost the mechanical strength and thermal shock resistance of the ceramic product, making it an extremely advantageous shape that can form in the ceramic body during sintering. With the fewest common impurities, such as calcium and sodium, that lead to the formation of this needle-shaped mullite in the ceramic industry, Maxworth Minerals provides high purity sillimanite powder.