- Time:Apr 23, 2023
magnesia alumina brick is an important refractory material, and its firing atmosphere has an impact on its physical and chemical properties. In general, the firing atmosphere of magnesia alumina bricks is a reducing atmosphere, that is, the gas in the furnace is rich in reducible gases, such as CO, H2, etc.
In the production process of magnesia alumina bricks, it is necessary to control the redox conditions of the sintering atmosphere to achieve the required physical and chemical properties. The method of adding a reducing agent is usually used to improve the firing atmosphere, such as adding coke powder, wood chips, etc. to the sintered material to decompose it at high temperature to generate reducible gas.
The reducing atmosphere can promote the reduction of alumina and the reaction of magnesium in magnesia alumina bricks, and generate more MgAl2O4 phases, thereby improving the compactness, strength and corrosion resistance of the bricks. At the same time, it can also reduce the pores and defects in the brick body, and improve its wear resistance and fire resistance.
The manufacturing process of fired magnesia bricks is the same as that of other refractory bricks, including crushing, crushing, mixing of ingredients, molding, drying and firing. However, the firing temperature of magnesia bricks is higher than that of other bricks, generally 1550-1600°C, and the firing temperature of high-purity products is 1750°C or even higher.
In short, the firing atmosphere of magnesia alumina bricks should be a reducing atmosphere, and proper redox control is required to ensure its excellent physical and chemical properties.
