Mullite insulation brick is a high alumina refractory material with mullite (3Al2O3-2SiO2) as the main crystalline phase. The general alumina content is between 65% and 75%. Mineral composition in addition to mullite, which contains low alumina also contains a small amount of glass phase and square quartz; high alumina also contains a small amount of corundum. Mullite insulation brick can be directly used for high-temperature kiln lining, has been widely used in shuttle kiln, roller kiln, glass and petrochemical kiln lining.
Product characteristics of mullite insulation brick.
1、Low thermal conductivity, with good thermal insulation and heat preservation effect.
2, Mullite insulation brick low thermal fusion, due to the low thermal conductivity, mullite series of lightweight insulation bricks accumulate little thermal energy, energy-saving effect in the intermittent operation is obvious;.
3, Low impurity content has a very low content of iron box alkali metal and other oxides, therefore, high refractoriness; higher aluminum content makes it still maintain good performance in the reducing atmosphere.
4, Mullite insulation brick hot state high compressive strength.
5、Accurate appearance size, speed up the masonry, reduce the use of refractory clay, ensure the strength and stability of the masonry, thus extending the life of the lining.
6, Mullite insulation bricks can be processed into special shapes. To reduce the number of bricklaying blocks and masonry joints.
Classification of mullite insulation bricks.
Mullite insulation bricks are mainly divided into light and heavy mullite bricks according to the density, and mainly divided into: 1350 mullite insulation bricks, 1450 mullite insulation bricks, 1550 mullite bricks, etc. according to the use of different temperatures.
Performance of mullite insulation brick and its application.
Higher fire resistance, up to 1790 ℃ or more. Load softening start temperature 1600～1700℃. Normal temperature compressive strength 70～260MPa. good thermal shock resistance. There are two kinds of sintered mullite bricks and electrofused mullite bricks. Sintered mullite bricks are made of high alumina clinker as the main raw material, with a small amount of clay or raw bauxite as binding agent, and are formed and fired. Electrofusion mullite brick with high bauxite, industrial alumina and refractory clay as raw materials, adding charcoal or coke fine particles as reducing agent, molding and then using reduction electrofusion method to manufacture. The crystallization of electrofused mullite is larger than that of sintered mullite, and the resistance to thermal shock is better than that of sintered products. Their high temperature performance mainly depends on the content of alumina and the uniformity of mullite phase and glass distribution. It is mainly used in hot blast furnace roof, blast furnace body and bottom, glass kiln heat storage chamber, ceramic sintering kiln, dead-end furnace lining of petroleum cracking system, etc.