Effect of MnO on Sintering and Microstructure of Al2O3-MgO-CaO Refractories

In the current study, Al₂O₃-MgO-CaO refractories were prepared at 1400–1600°Cby the addition of MnO micro-powders, and the effect of MnO addition on densification behavior of the refractory was discussed. The results showed that the doped MnO dissolved to MgAl₂O₄ phase, and promoted the growth of MgAl₂O₄ grains by the formation of MgAl₂O₄ solid solution. As a result, the dense microstructure was obtained, with the apparent porosity decreased from 19.2% to 5.4% and the bulk density increased from 2.78g/cm3 to 3.15g/cm3 after firing at 1600°C for 2h by the addition of 4% MnO. In addition, a texture microstructure was observed, which is considered to be favorable to improve mechanical properties and the service life of Al₂O₃-MgO-CaO system refractories.