Brief Introduction of Sintered Mullite Brick

Sintered mullite brick is a kind of high-temperature mullite brick. It uses high bauxite, industrial alumina, and refractory clay as raw materials, and adds charcoal or coke fine particles as reducing agents. After forming, it is manufactured by reduction electrofusion The sintering temperature of sintered mullite bricks is usually above 1600°C. Such a high sintering temperature makes it difficult to produce sintered mullite bricks on a large scale. Using the activity of active SiO2, adding an appropriate amount of active SiO2 to the ingredients can make sintered mullite bricks Stone bricks are sintered at 1550°C.

1. Physical indicators of sintered mullite bricks

The apparent porosity of the sintered mullite brick is 20.88%, the bulk density is 2.61g/cm³, the compressive strength at room temperature is 84.4MPa, and the creep rate at 1550°C and 50h high temperature is 0.796%.

2. The difference between sintered mullite bricks and fused mullite bricks

The high-temperature flexural strength of sintered mullite bricks is much higher than that of fused mullite bricks, which is due to the interlacing of some small but well-developed crystal networks in the former structure. The latter has good volume stability and excellent creep resistance due to larger crystals. Moreover, fused mullite bricks have better corrosion resistance than sintered mullite bricks of the same composition. This is because when corroded by alkali substances at high temperatures, mullite will generate corundum and nephrite liquid phases, and the nephrite liquid phase has low viscosity, which is easy to lose and cause brick damage. Due to the relatively high porosity of sintered mullite, the above reaction can be carried out inside the brick body, and the destructive power is much greater; while the fused mullite brick has a high density, the above reaction can only be carried out on the surface of the refractory brick, destroying relatively weaker.

3. Common types of mullite insulation bricks

In addition to sintered mullite bricks, our common mullite bricks include low-creep mullite bricks, low-creep sintered mullite bricks, mullite corundum bricks, mullite sillimanite bricks, sillimanite Bricks, etc. These refractory bricks all contain mullite, but the content of each type is different, and the occasions used are also different.

Although the price of mullite bricks is much higher than that of high alumina bricks, its superior performance determines its wide use. The properties of mullite refractory bricks are mainly determined by the properties of mullite. It has high refractoriness, high load softening temperature, low high-temperature creep rate, excellent thermal shock resistance, slag erosion resistance, high shear modulus, etc. Mullite refractory bricks are widely used, mainly used in high-temperature hot blast stoves, large blast furnace hearths and bottoms, steelmaking electric furnace roofs, ceramic industrial kiln linings, kiln furniture, and glass kiln cement kiln linings, etc.