Investigating the high temperature properties of MgO-CaO Refractories through the Addition of Nano- and Micro-Sized ZrO۲

The present study investigated the effect of ZrO۲ powders of different sizes on the performance of MgO-CaO refractories by sintering them together at ۱۶۰۰°C. The densification of the refractories was found to increase with an increase in ZrO۲ content, owing to a reaction between the added ZrO۲ and CaO, which resulted in volume expansion and subsequently led to the formation of CaZrO۳. Such formation caused microstructural modification by introducing CaZrO۳ particles at grain boundaries and triple points throughout the microstructure, thereby enhancing the thermal shock resistance (TSR) of the MgO-CaO refractories. According to the study, ZrO۲ nanoparticles demonstrated superior efficacy due to their improved dispersion at a smaller amount of ۶ mass%. Inclusion of nano- and micro- sized ZrO۲ led to a decrease in amount of free CaO particles in the refractories, resulting in densification increase from ۳.۲۷ to ۳.۵۸ and ۳.۵۳ g/cm۳, respectively. Additionally, nano-sized ZrO۲ enhanced the thermal shock resistance of refractory from ۱۱ to ۴۲ cycles which showed better performance in comparison with micro-sized ZrO۲ (۳۵ cycles). Moreover, inclusion of ZrO۲ increased slag corrosion resistance by increasing viscosity of liquid phase, thus inhibiting additional slag penetration at high temperatures

کلیدواژه ها:

zirconium dioxide ، MgO–CaO ، CaZrO۳ ، slag corrosion ، Thermal shock resistance