Role of MgO in prevention of lining corrosion in converters Mar06

Role of MgO in prevention of lining corrosion in converters...

        Role of MgO in prevention of lining corrosion in converters In the present day primary steelmaking processes, magnesia carbon bricks are the most commonly used refractory material for lining of the primary steel making furnace. The lining life differs from steel plant to steel plant because of refractory, operation and maintenance practices (Fig. 1). Fig 1 Effects of various refractory wear factors The effect of different parameters on the lining life is elaborated in Table 1 Table 1 Effects of different parameters on lining life Sl.No. Parameter Effect on life Severity of influence 1 Hot Metal Si Negative Medium Mn Positive Low Ti Negative Low 2 Slag Total Fe Content Negative High Basicity(CaO/SiO2) Positive Medium CaF2 Addition Negative Medium MgO content Positive High Al2O3 Content Negative Low Lime Addition Positive Medium 3 Blowing End point Temperature Negative High Blowing duration Negative Medium Production rate (Heats/day) Positive Medium Slag Volume Negative Low Atmosphere (CO/CO2) Positive Medium Delay in charging lime Negative Medium 4 Design of Converter Vessel volume Positive Low Cone angle Positive Low Multi hole blow lance Positive high The relationship of some of the parameters influencing the lining life of the converter is shown in Figure 2.   Fig 2 Relationship of the parameters affecting the lining life During the process of steel making, the main wear mechanisms are impact, corrosion, thermo-mechanical stresses and erosion. Though all the factors are important but corrosion due to dissolution of refractory material in the slag has a major effect on the lining life. During the process of steel making various oxides are produced which are fluxed with calcined lime to produce steel making slag. This slag is corrosive in nature and is in continuous touch with the surface of the converter lining. Due...