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.