Erosion of magnesia carbon brick in the ladle furnace

In the ladle, due to the complex physical and chemical environment of the slag line, the furnace lining is the most vulnerable to damage. The chemical attack of steel slag on the magnesia carbon brick is mainly through the dissolution of magnesia and the oxidation of the graphite in the brick body. Under the combined action of two factors, the magnesia carbon brick is damaged.

1. The effect of alkalinity: the lower the alkalinity of the slag, the more beneficial it is to the erosion of magnesia-carbon bricks. The increase in alkalinity of the slag will reduce the activity of FeO in the slag, and the decrease of FeO activity will lead to the diffusion capacity of FeO.

2. The influence of MgO: Osbom et al. found that the MgO content in the reaction layer of the residual bricks of the LF slag line is very high. When the MgO content in the slag is low, it will affect the refractory magnesia carbon brick. The erosion rate of bricks is very large, and the lower the alkalinity, the faster the erosion of magnesia carbon bricks.

3. The influence of Al2O3: Al2O3 in the slag will reduce the melting point and viscosity of the slag, which greatly increases the penetration and erosion of the magnesia carbon brick by the slag, and can also corrode the magnesia from the magnesia grain boundary, making periclase Dissociate.

4. The influence of FeO: Firstly, FeO in the slag easily reacts with the graphite in the magnesia carbon brick at high temperature, and produces bright white iron beads to form a decarburized layer as shown in Figure 1. Secondly, the magnesia will interact with the graphite in the slag. FeO will form a low melting point of rich magnesium. AT&S believes that in the process of repeated heating and cooling of the ladle, due to the phase transformation between the magnesium richite and the mafic ore accompanied by the volume change, the magnesia on the working surface will crack, which will lead to the formation of magnesia. Dissolution, foreign studies believe that the increase in iron content in steel slag is detrimental to the life of ladle magnesia carbon bricks. First, iron oxides accelerate the oxidation of graphite, and secondly, it increases the solubility of MgO in the slag and accelerates the dissolution of periclase. The combined effect of the two is the erosion of magnesia carbon bricks.

Article Source:Erosion of magnesia carbon brick in the ladle furnace
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