(1) Corrosion of magnesia carbon brick by slag:

In the ladle, the lining of the slag line is most vulnerable to damage due to the complex physical and chemical environment. The chemical attack of slag on magnesia-carbon bricks is mainly through the dissolution of magnesia and the oxidation of carbon in the matrix of magnesia-carbon bricks. Under the combined action of the following factors, the magnesia-carbon bricks are damaged:

 

(2) Oxidation of carbon in magnesia carbon brick:

When the magnesia carbon brick is in contact with the molten slag, the carbon will react with FeO and other oxides in the molten slag to form a decarburized layer under certain conditions, resulting in a loose structure of the magnesia carbon brick working surface, which is the damage of the magnesia carbon brick main reason. Carbon reacts with CO2, O2, SiO2 and other oxides and is continuously oxidized by iron oxides in the slag; secondly, the loose structure formed by the decarburization layer produces larger cracks and pores under the action of thermal expansion and scouring of the slag, so that the slag can easily penetrate. It also forms a low-melting phase with MgO. At the same time, under the action of violent mechanical agitation in the molten pool and violent scouring of steel slag, the surface layer structure of the magnesia carbon brick is changed, and it is gradually damaged from the outside to the inside, resulting in serious damage to the magnesia carbon brick. After the temperature exceeds a certain value, the brick structure will be destroyed and rapidly corroded. This is due to the consumable reaction between MgO and graphite at high temperatures.

 

(3) The influence of stomata:

Due to the existence of micro-pores inside and on the surface of the magnesia carbon brick, the erosion of the magnesia carbon brick is more likely to occur. During the use of magnesia-carbon bricks, the pores play an accelerating role in the formation of the decarburized layer, which in turn causes the slag to corrode the magnesia-carbon brick refractories more seriously.