# Evaluation of Factors Affecting the MgO-C Refractory Lining Degradation in a Basic Oxygen Furnace
## 3 Results
### Analysis of the Influence of Slag Viscosity on the Wear of the BOF MgO-C Refractory Lining  
Viscosity, a vital converter slag parameter, influences clogging in pores and cracks, impacting MgO-C refractory. It is determined by chemical composition. Understanding component influence is crucial for controlling slag composition during steelmaking and the entire BOF campaign. The average proportion of CaO in the BOF slag during the campaign was 46.12%, which means that the CaO compound also has the largest representation in the BOF slag; therefore, the variance of the CaO values also has the largest effect on the dynamic viscosity of the BOF slag. The large variance of the CaO values (Figure 20a) significantly affected the slag viscosity evolution during the campaign. The average MgO content of the BOF slag during the campaign was 8.27%. The dispersion rate of the MgO content (Figure 20b) was in the average range; hence, the variation of the MgO content during the campaign did not have a major influence on the BOF slag viscosity. The evolution of the MgO content is mainly related to the control of the slag basicity value during the smelting process and, therefore, throughout the campaign. It can be seen from Figure 21a that significant fluctuation occurred in the FeO content of the BOF slag during the campaign. Chemically, this resulted in significant variation in the dynamic viscosity value of the BOF slag, while the average FeO content of the BOF slag during the campaign was 12.75%; thus, the overall effect on the dynamic viscosity was moderate. In the case of MnO (Figure 21b), much less variation in MnO content can be seen during the campaign. The average MnO content in the BOF slag was only 3.81%; thus, MnO contributed less to the evolution of the dynamic viscosity of the BOF slag than other compounds. During the campaign, the average SiO\({}_{2}\) content in the BOF slag was 11.37%. Therefore, together with the variance of the FeO content in the BOF slag (Figure 22a), SiO\({}_{2}\) content had the greatest chemical influence on the dynamic viscosity value during the campaign. However, due to its average content in the BOF slag, the overall influence on the final slag viscosity was suppressed by the CaO content. In the case of P\({}_{2}\)O\({}_{5}\) as a component of the BOF slag (Figure 22b), the magnitude of the influence of P\({}_{2}\)O\({}_{5}\) on the viscosity of the slag during the campaign was small; likewise, the average P\({}_{2}\)O\({}_{5}\) content of the BOF slag during the campaign had a very low value of 0.94%.  
Figure 19: Technology solution of adding fluxes via chute to the BOF. (**a**) Top view of impacted S3 zone; (**b**) side view of falling direction of added fluxes with impact zone in slag line area.  
Figure 21: Comparison of converter slag viscosity at maximum and minimum slag component levels during the campaign as a function of temperature. (**a**) FeO in slag; (**b**) MnO in slag.  
Figure 22: Comparison of converter slag viscosity at maximum and minimum slag component levels during the campaign as a function of temperature. (**a**) SiO\({}_{2}\) in slag; (**b**) P\({}_{2}\)O\({}_{5}\) in slag.  
Figure 20: Comparison of converter slag viscosity at maximum and minimum slag component levels during the campaign as a function of temperature. (**a**) CaO in slag; (**b**) MgO in slag.