Low temp sintering mulite kiln furnitures

Abstract

The present invention relates to a kind of low-temp. sintered mullite kiln furniture, belonging to refractory material product. It is characterized by that it uses mullite granules and fine powder asmain material, its composition also contains amorphous alumina and superfine quartz powder, and the described amorphous alumina is obtained by using industrial aluminium hydroxide through the processes of suspension heating to 650 deg.C, dewatering and air quenching, and the described superfine quartz powder is obtained by using quartz sand through the process of pneumatic vibration grinding. Said invention utilizes the raise of activity of forming mullite component to reduce firing temp. and ensure the service performance of mullite kiln furniture.

Description

technical field [0001] The invention relates to a refractory material product, especially a mullite kiln furniture. technical background [0002] Mullite kiln furniture is generally combined with mullite by reaction sintering. There are three main methods. First, high-purity clay is used as the binder for high-temperature firing. The problem is that the Na + 、K + Such impurity ions are brought into the glass phase during the sintering process to form ceramic liquid phase sintering, which affects the performance of kiln furniture products. In addition, the sintering temperature of this method is close to 1600 ° C, while the kiln temperature commonly found in my country's refractory material factories is only More than 1400 degrees; second, mullite, corundum, quartz particles and fine powder are high-pressure molded and fired at high temperature. Although the incorporation of impurities is avoided, the mullite crystal of the product can develop well and have excellent performa...

AI Technical Summary

Problems solved by technology

[0002] Mullite kiln furniture is generally combined with mullite by reaction sintering. There are three main methods. First, high-purity clay is used as the binder for high-temperature firing. The problem is that the Na + 、K + Such impurity ions are brought into the glass phase during the sintering process to form ceramic liquid phase sintering, which affects the performance of kiln furniture products. In addition, the sintering temperature of this method is close to 1600 ° C, while the kiln temperature commonly found in my country's refractory material factories is only More than 1400 degrees; second, mullite, corundum, quartz particles and fine powder are high-pressure molded and fired at high temperature. Although the incorporation of impurities is avoided, the mullite crystal of the product can develop well and have excellent performance, but it still needs The sintering can only be completed at a very high sintering temperature, and it needs to be kept at a high temperature for a long time; third, similar to the second one, the quartz fine powder is changed into active silica powder, and the sintering temperature is lowered by the activity of silica powder. down to 1450°C, but the added active silica powder is a by-product of ferroalloy production, and its silica composition only accounts for more than 90%. Even if high-purity active silica powder is used, its silica composition is only Can be greater than about 95%, and the rest of the impurity components are Na + 、K + and CaO and Fe 2 o 3 Etc., more glass phases are produced during the sintering process, which reduces the performance of the product

[0003] The components that produce mullite are aluminum oxide and silicon dioxide. Only by increasing the activity of the mullite-producing components can the sintering temperature be reduced. Although the above third method reduces the sintering temperature by increasing the activity of silicon dioxide, due to The source of raw materials is limited, so that the performance of mullite kiln furniture is not good

Domestic aluminum oxide powder is generally passed through α-Al 2 o 3 It is prepared by fine grinding, even if it is finely ground to below μm level, its activity is quite limited, and the synthesis of mullite with silica at high temperature still needs extremely high temperature to complete