AZS fused cast zirconium corundum brick is commonly known as white iron brick or cast zirconia corundum brick. It is an important refractory material to ensure the normal operation of the glass melting furnace. At present, the glass melting furnace at home and abroad increases the melting rate, prolongs the kiln age, and reduces the fuel consumption mainly because of the use of this refractory material.
Electrofused zirconium corundum brick-fused Zirconium corundum brick-AZS electrofusion brick can also be called corundum-oblique zircon product. Its main chemical composition Al2O3 is 50% to 70%, ZrO2 is 20% to 40%, and the rest is SiO2. The main mineral composition is oblique zircon (ZrO2), corundum (α-Al2O3) and glass phase. The oblique zircon crystal forms a brick body backbone. ZrO2 has a high melting point (2715 ° C), good chemical stability, and strong resistance to acidic and alkaline media, especially against glass.
The fused zirconium corundum brick-fused Zirconium corundum brick AZS electrofusion brick has improved performance with the increase of ZrO2 content. Generally, the zirconium corundum brick is divided into several grades according to the amount of ZrO2, such as 33%, 36. %, 41% of the three levels, there are also divided into 30%, 40X, 50% level, not yet unified. At present, more products are used containing 33% zirconium, the density is 3.65-3.7 g/cm3, and the use temperature is about 1700 °C.
Electrofused zirconium corundum brick-fused Zirconium corundum brick-AZS electrofusion brick is used in industrial furnaces such as glass melting furnace. The use part in glass melting furnace is to build upper wall, small furnace, small furnace and tongue. and the chest wall and so on.
The following problems should be noted in the use of fused zirconium corundum brick-fused zirconium corundum brick-AZS electrofusion brick:
(1) Irregular change of thermal expansion The expansion curve of fused zirconia corundum brick has an anomaly near 1000 °C, and the internal ZrO2 crystal undergoes reversible crystal transformation, which has a large volume change. Therefore, products containing ZrO2 should not be used. At temperatures around 1000 °C, there are often sharp fluctuations in the temperature. When the oven is baked, the temperature change at 900~1150 °C should not be too large, generally it can't exceed 15 °C/h, and it requires a steady temperature rise. Some parts should be protected from blowing cold air and protected by other bricks to prevent cracking.
(2) When the shrinkage hole is cast, the shrinkage hole often appears at the casting port. Here, the brick body has more pores and the density is poor. Therefore, when the glass wall of the glass melting part is made, the shrinkage hole is directed toward the direction of the kiln. When the mouth is facing outward, when the brick is eroded to a very thin surface, it will cause a leakage of glass liquid. When used in the upper flame space of the kiln, the service life is very long, and there is no problem of running the glass. Therefore, the casting port is used outward to extend the service life.
(3) The eutectic fused zirconium corundum brick is in contact with the clay refractory brick. The eutectic phenomenon occurs at 1300 °C. Therefore, when refractory material is selected, the two refractory materials with severe eutectic phenomenon should be avoided. Buildings, such as silica bricks, are easily eroded by fused zirconia corundum bricks under fused zirconium corundum bricks.
