Product characteristics and classification of mullite insulation fire refractory bricks for furnace

Mullite insulation brick is a high alumina refractory material with mullite (3Al2O3 2SiO2) as the main crystal phase. Generally, the alumina content is between 65% and 75%. In addition to mullite, the mineral composition contains a small amount of vitreous phase and cristobalite with a lower alumina content; a small amount of corundum is also contained in the higher alumina content. Mullite thermal insulation bricks can be directly used in the lining of high temperature kilns, and have been widely used in the lining of shuttle kilns, roller kilns, glass and petrochemical kilns.

One,Product characteristics of mullite insulation bricks:

1. Low thermal conductivity, with good thermal insulation effect;

2. The mullite thermal insulation brick has low thermal melting. Due to the low thermal conductivity, the mullite series lightweight thermal insulation brick accumulates little heat energy, and the energy saving effect is obvious in intermittent operation;

3. Low impurity content has a very low content of oxides such as alkali metals in iron boxes, therefore, high refractoriness; higher aluminum content enables it to maintain good performance in a reducing atmosphere;

4. The mullite insulation brick has high thermal compressive strength;

5. Accurate appearance size, speed up the masonry, reduce the use of refractory mud, ensure the strength and stability of the masonry, thereby prolonging the life of the lining;

6. Mullite insulation bricks can be processed into special shapes. To reduce the number of bricks and joints.

Second, the classification of mullite insulation bricks:

Mullite insulation bricks are mainly divided into light and heavy mullite bricks according to different densities, and are mainly divided into: 1350 mullite insulation bricks, 1450 mullite insulation bricks, 1550 mullite bricks, etc. .

The performance and application of mullite insulation brick: high refractoriness, up to 1790 ℃ or more. The starting temperature of softening under load is 1600-1700 ℃. The compressive strength at room temperature is 70 to 260 MPa. Good thermal shock resistance. There are two types of sintered mullite bricks and fused mullite bricks. Sintered mullite brick is made of high alumina bauxite clinker as the main raw material, adding a small amount of clay or raw bauxite as a binder, and is made by molding and firing. Fused mullite bricks use high bauxite, industrial alumina and refractory clay as raw materials, add charcoal or coke fine particles as reducing agents, and use reduction electrofusion method to manufacture after molding. The crystallinity of fused mullite is larger than that of sintered mullite, and its thermal shock resistance is better than that of sintered products. Their high temperature performance is mainly determined by the alumina content and the homogeneity of the mullite phase and glass distribution. Mainly used for hot blast stove top, blast furnace shaft and bottom, glass melting furnace regenerator, ceramic sintering kiln, dead angle lining of petroleum cracking system, etc.