The chemical attack of slag on MgO-C brick is mainly through the dissolution of MgO and the oxidation of carbon in MgO-C brick matrix

1. The influece of basicity: the lower the basicity of slag is, the more favorable the erosion of MgO-C brick is. If the basicity of slag increases, the activity of SiO2 in slag will decrease, which can reduce the oxidation of carbon. Meanwhile, with the increase of basicity, the activity of FeO in slag will decrease, which will slow down the erosion behavior of slag to MgO-C brick;

2. Influence of MgO: when osbom analyzed the composition of LF slag line, it was found that MgO content in slag layer was as high as 30%. It was considered that the higher the MgO content in slag, the slower the erosion of MgO-C brick, and the higher alkalinity, the corrosion of magnesia carbon brick was also slowed down

3. The influence of Al2O3: Al2O3 in slag will reduce the melting point and viscosity of slag, increase the wettability between slag and refractory, make slag more easily penetrate from magnesia grain boundary, and make periclase separate from magnesia carbon brick matrix.

4. The influence of FeO: firstly, FeO in slag is easy to oxidize with graphite in MgO-C brick at high temperature and produce bright white iron bead to form decarburization layer. Secondly, periclase in MgO-C brick reacts with FeO in slag to form low melting point product.

In the process of repeated heating and cooling of the ladle, the MgO on the refractory surface is broken and the brick body is dissolved due to the inconsistency of the thermal expansion rate between the magnesium iron compound low melting point product and the magnesite. Foreign scholars also believe that the increase of iron content in steel slag is unfavorable to the service life of MgO-C brick. Firstly, iron FeO accelerates the oxidation of carbon on the surface of MgO-C brick, and secondly, FeO reacts with MgO to loosen the structure of working face of MgO-C brick. Under the joint action of these two points, the erosion of MgO-C brick is accelerated.