The Development Of Zirconia Refractories

Due to the strong corrosion resistance, zirconia refractories have been developing rapidly and found their wide application in many industries. Besides traditional products like fused cast AZS and sintered AZS block, some novel products has been developed.

Fused cast high zirconia blockIn the fused cast AZS block, ZrO2 is the oxide with the strongest corrosion resistance. in recent years, fused cast high zirconia block has been developed for the production of non-alkali and borate glass. However, compared to fused cast AZS, it has a larger volume expansion when cooled. Zirconia-containing monolithic refractoryZirconia-containing monolithic refractory has been developed early. Recently, it has some new development. Zirconia-containing castable and ramming masses have been widely used in the lings of the glass furnace and ladles. Zirconia-containing Al2O3 refractoryZirconia-containing Al2O3 refractory is made of high sintered bauxite, sintered corundum and fused corundum as the main raw materials, with addition of zirconite, zircon brick or monolithic materials. With the presence of ZrO2 aggregates, the aggregates forms micro-cracks with the surrounding mullite and corundum, with Tabular alumina and ZrO2 interspersing among them, forming a composite reinforcing structure. ZrO2 itself has radial micro-cracks, which contributes to the release and dispersion of thermal stress. This type of zircon refractory, known as spalling-resistance high alumina brick, has been used in cement kilns. By adding ZrO2 to corundum sagger for the precision ceramic industry and corundum brick for the petroleum cracking furnace, their operating temperature, thermal stability and service life can be improved significantly. In addition, the continuous casting skateboard also uses zirconia-containing Al2O3 refractory. Zirconia-containing CaO refractoryZirconia-containing CaO refractory mainly consist of CaO and ZrO2. They are mainly used in immersion nozzles and can effectively suppress clogging of Al2O3. CaZrO3 can react with Al2O3 in the molten steel and forms a smooth layer, which can prevent the adhesion of Al2O3. Zirconia-containing magnesium spinel refractoryZirconia-containing magnesium spinel refractory is mainly used in the burning zone of the large dry-process cement kiln. It is developed by Japan. By adding ZrO2 to magnesium spinel, it has dense structure, high temperature strength and good volume stability, which grant the brick good corrosion resistance, spalling resistance and material adhesion resistance. Zirconia-containing MgO refractoryBy adding ZrO2, the thermal stability and strength can be improved. Compared to magnesium chrome brick, it is environment friendly. It is expected to replace magnesium chrome brick in the cement kiln burning zone. It can also be used in other thermal equipment instead of magnesia bricks. Zirconia-containing aluminum carbon refractoryAluminum carbon refractory is a kind of metallurgical refractory widely researched and developed. It is mainly used for the skateboard and tundish outlet. To improve the corrosion resistance and thermal stability of the skateboard and tundish outlet, ZrO2 can be added to aluminum carbon refractory. Monoclinic zirconia crystals has a low thermal expansion coefficient and the phase change can generate micro-cracks. The addition of ZrO2 can reduce the content of SiO2, thus the performance of the skateboard is improved. Zirconia-containing MgO CaO refractoryBy adding ZrO2 to calcareous dolomite, its structure becomes more impact, CaO and periclase grains are well-developed, the boundaries are more obvious, and the direct bonding between CaO grains becomes much firmer, which greatly promoted the solid-state sintering of CaO. By adding ZrO2 to dolomite, CaO particles is enclosed in the network of periclase and periclase particles, which greatly contributes to the solid-state sintering of dolomite. It can significantly improve the softening temperature under load. Zirconia-containing magnesia carbon refractoryThe magnesia carbon refractory has good resistance to basic slag at high temperature, but its surface is easy to crack due to thermal stress and the carbon is easy to be oxidized. Adding zircon can reduce the thermal stress and the oxidization of carbon. Zhengzhou Sunrise is a refractory material supplier from China, offering high quality refractory materials for glass furnaces, including fused cast AZS block, fused cast alumina block, fused cast high zirconia block, mullite brick, zircon brick, alumina bubble brick, magnesia brick, sillimanite brick, corundum brick, low porosity fireclay brick, high alumina brick, all kinds of glass furnace ramming masses, etc..

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