# Evaluation of Factors Affecting the MgO-C Refractory Lining Degradation in a Basic Oxygen Furnace
## 3 Results
### Refractory Lining Wear Mechanism in Basic Oxygen Furnace
#### 3.6.2. Wear Mechanism of MgO-C Refractory in the Basic Oxygen Furnace  
The wearing mechanism of MgO-C refractory in the BOF comprises the following steps:  
* Decarburization of MgO-C refractory layer by oxygen: The decarburized refractory layer is created by saturation of free oxygen dissolved in metal, the oxide form of oxygen in molten slag, or blown oxygen into the upper refractory layer. This forms a decarburized layer saturated with slag oxides.
* Reaction of refractory and slag through the glass phase
* Partial dissolution of iron oxides in periclase: Partial dissolution of iron oxides in MgO creates a solid Fe\({}_{2}\)MgO\({}_{4}\) solution. This process reduces the amount of iron oxides in BOF slag and inhibits the effects of refractory corrosion.
* Formation of magnesium silicate: BOF slag also contains a noticeable amount of SiO\({}_{2}\), which causes significant periclase corrosion. Based on the thermodynamic calculations, the most expected chemical products are given in Table 11.  
* Formation of dicalcium silicate coating: Dicalcium silicate is formed by the interactive reaction of slag and periclase (Table 12) and forms a coating above the refractory. This shield slows the corrosive action of the BOF slag into the refractory.
* Reaction of iron oxides with carbon: Carbon from the refractory material reduces iron oxides from slag. The most expected results of carbon and iron oxides are given in Table 13.
* Solid solution formation: Iron oxides react with carbon and periclase (MgO). The reaction of iron oxides with periclase produces solid solutions (melting point 1750 \({}^{\circ}\)C) according to the formula Fe\({}_{2}\)O\({}_{3}\) + MgO = MgFe\({}_{2}\)O\({}_{4}\).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Name**} & **Chemical** & \multicolumn{2}{c}{**\(\Delta\)G kJ.mol\({}^{-1}\)**} & **Melting** \\ \cline{3-5}  & **Formula** & **1300 \({}^{\circ}\)C** & **1700 \({}^{\circ}\)C** & **Point \({}^{\circ}\)C** \\ \hline Gehlenite & Ca\({}_{2}\)Al\({}_{2}\)SiO\({}_{7}\) & \(-1278.827\) & \(-1911.329\) & \(1584\) \\ \hline – & Ca\({}_{2}\)P\({}_{2}\)O\({}_{7}\) & \(-520.103\) & \(-529.981\) & \(1353\) \\ \hline – & Mg\({}_{3}\)(PO\({}_{4}\))\({}_{2}\) & \(-419.220\) & \(-430.862\) & \(1353\) \\ \hline Dicalcium/ferrite 1  & Ca\({}_{2}\)Fe\({}_{2}\)O\({}_{5}\) & \(-342.090\) & \(-290.176\) & \(1477\) \\ \hline Akermanite & Ca\({}_{2}\)MgSi\({}_{2}\)O\({}_{7}\) & \(-146.355\) & \(-126.345\) & \(1454\) \\ \hline Diopside & CaMgSi\({}_{2}\)O\({}_{6}\) & \(-139.683\) & \(-166.519\) & \(1391\) \\ \hline Anorthite & CaAl\({}_{2}\)Si\({}_{2}\)O\({}_{8}\) & \(-138.618\) & \(-147.361\) & \(1550\) \\ \hline Monticellite & CaMgSiO\({}_{4}\) & \(-101.513\) & \(-101.158\) & \(1503\) \\ \hline Cordierite & Mg\({}_{2}\)Al\({}_{4}\)Si\({}_{2}\)O\({}_{18}\) & \(-98.826\) & \(-155.127\) & \(1467\) \\ \hline Dicalcium/ferrite 2  & \(-76.285\) & \(-106.286\) & \(1477\) \\ \hline Fayalit & Fe\({}_{2}\)SiO\({}_{4}\) & \(-21.446\) & \(-31.835\) & \(1217\) \\ \hline \hline \end{tabular}
\end{table}
Table 10: List of the most expected reaction products within the gunning material.