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High Quality Zircon Mullite Bricks Sold by Sunrise Refractories

By introducing ZrO2 into the A12O3-SiO2 brick to improve the microstructure of mullite, the chemical corrosion resistance, thermal shock resistance and expansion coefficient of mullite can be improved. This mullite brick containing ZrO2 is commonly known as Zirconium mullite bricks, generally produced by electrofusion, are also produced by sintering.
Sintered zirconium mullite brick is a special refractory material made by introducing zirconia into mullite matrix by using industrial alumina and zircon concentrate as raw materials.
The introduction of zirconia into mullite bricks and the use of zirconia phase transformation toughening can greatly improve the high temperature mechanical properties of mullite materials. Zirconium oxide promotes the sintering of mullite materials. The addition of ZrO2 accelerates the densification and sintering process of ZTM materials due to the formation of low melting materials and the formation of vacancies. When the mass fraction of ZrO2 is 30%, the relative theoretical density of the body fired at 1530 ° C reaches 98%, the strength reaches 378 MPa, and the toughness reaches 4.3 MPa·m 1/2.
Zirconium mullite bricks prepared by reaction sintering using industrial alumina and zircon as raw materials are difficult to process due to simultaneous reaction and sintering. Usually, it is first densified at 1450 ° C during firing, and then heated to 1600 ° C for reaction. ZrSiO4 is decomposed into ZrO 2 and SiO 2 at more than 1535 ° C, wherein SiO 2 and Al 2 O 3 react to form mullite, which is decomposed by ZrSiO 4 . A part of the liquid phase appears, and the decomposition of ZrSiO4 can refine the particles and increase the specific surface area, thereby promoting sintering.
Studies have shown that when the addition amount of zircon is less than 54.7%, the microstructure of the sintered sample gradually transitions from a network of columnar corundum to a network structure composed of columnar mullite as the amount of zircon added increases. . The high-temperature flexural strength (1400 °) of the sample also increases with the increase of zirconia content, and a larger value occurs when the zirconia content is 23.7%, and then the strength decreases. The addition of zircon contributes to the improvement of thermal shock resistance.