Introduction of mullite lightweight insulating fire brick 1

Mullite lightweight insulating fire brick is a kind of high alumina refractory material with mullite(3Al2O3·2SiO2) as its main crystal phase. Normally its alumina content is 65&-75%. According to bulk density, mullite lightweight insulation brick can be classified into three types: 0.8, 1.0, 1.2.
Introduction of mullite
Mullite is a kind of andalusite which is colorless and rich in alumina content. Its crystal is column-like or needle-like, melting temperature is 1910 °C. It is the main component of ceramic products. Mullite is mainly aluminosilicate minerals, and its natural minerals are rare in the earth’s crust. Because it was discovered in the island of Moray Scotland, it is known as mullite. Mullite is a kind of high-quality refractory raw material. It has uniform expansion, good thermal shock resistance, high load softening temperature, low creep value under high temperature, high hardness, good chemical resistance etc.
The active constituents of mullite are alumina and silica. Among various raw materials, the alumina content determines the refractoriness of the material. Therefore, in actual production, we generally adjust content of alumina to control the production process to guarantee the quality of mullite products. The refractory bricks produced have high refractoriness. Its refractoriness can be up to 1790 °C. The load softening temperature can reach 1600~1700 °C. The compression strength can reach 70~260MPa. Thermal shock resistance is good.
This issue we mainly introduced mullite. Hope this can bring help to furnace builders. Next issue we will continue to introduce the six characteristics of mullite insulation brick. Please stay tuned.