Silica mullite brick, also called high wear-resistant refractory brick, is a refractory brick made of mullite, andalusite, silicon carbide and super-grade homogenized bauxite as the main raw materials, after mixing, high-pressure molding, and high-temperature firing.
Silica mullite brick usage:
Silica mullite brick has the high temperature resistance of mullite, but also has the advantages of wear resistance, corrosion resistance, and good thermal conductivity of sillimanite. In addition to good high temperature resistance and corrosion resistance, silica mullite bricks also have better thermal shock resistance than high alumina bricks. The practice of many cement plants has proved that it is used in the upper transition zone of 5000t/d new dry-process water kilns. A 12-month life span can be obtained; it can be used in the upper transition zone of a 2500t/d new dry-process cement kiln, and a life span of 1 to 2 years can be obtained.
Silica mullite brick advantages:
After high alumina bricks are added with silicon carbide, the wear resistance, thermal shock resistance, load softening temperature and corrosion resistance of high alumina bricks can be greatly improved, and a new type of refractory brick with superior comprehensive performance can be manufactured.
The Mohs hardness of silicon carbide is as high as 9.5. Adding silicon carbide to high alumina bricks improves the hardness of refractory bricks. In this way, when the abrasive particles are in contact with the refractory bricks, the depth of the abrasive particles chiseled into the refractory bricks is limited, and the possibility of cutting certain substances from the surface of the refractory bricks when the abrasive particles slide on the surface of the refractory bricks is reduced, thereby improving the refractory bricks Abrasion resistance. Silicon carbide has a high thermal conductivity [84W/(m.K)] and a moderately low thermal expansion coefficient (4.7×10-6/K). Adding silicon carbide to high alumina bricks improves the thermal conductivity of the material and reduces the thermal expansion coefficient of the material. Thus, the thermal shock resistance of the high alumina brick can be significantly improved.
Silicon carbide is oxidized to form SiO2 and CO, and SiO2 reacts with Al2O3 to form mullite. Both of these reactions are accompanied by a large volume increase. The reaction product mullite also has good high temperature performance. Therefore, adding an appropriate amount of silicon carbide helps to compensate for the shrinkage of refractory bricks after re-firing, and to increase the softening temperature and creep resistance of the refractory bricks.
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