Slag Resistance of High Alumina Brick

The slag resistance of high alumina brick refers to its ability to resist the chemical corrosion and penetration of slags. It is one of the important indicators for the quality of high alumina bricks. 

In various refining furnaces, the chemical corrosion and penetration of slags is one of the reasons for the damage of the linings. So, the slag resistance of lining bricks is important for the service life of the furnace. The slag resistance is up to the chemical composition and structure of bricks and the alkalinity and temperature of slags. 

 

The main components in high alumina bricks are MgO and CaO. The two components show different slag resistance. MgO has good slag resistance. It is difficult to react with slags. Even if it reacts with slags, there is no substance with low melting points produced. MgO can form solid solution with FeO without the formation of liquid phase. MgO can greatly resist the SiO2 in slags. However, MgO has bad penetration resistance to slags. The slags can easily penetrate into MgO and form a variant layer. 

 

The alkalinity (CaO + MgO /SiO2) and temperature of slags have great impact on the slag resistance of high alumina bricks. High alumina bricks have bad resistance to acid slags, but good resistance to alkali slags which increases with the increasing of alkalinity. With the increasing of temperature, the corrosion of slags becomes more aggressive and the viscosity of slags is lower. So, the corrosion and penetration of slags are more serious. 

 

So, in the refining furnace, changing the temperature and alkalinity of slags is an effective way to reduce the corrosion and penetration to high alumina bricks and prolong the service life of the furnace.