THE EFFECT OF NANO METER SIZE ZRO۲ PARTICLES ADDITION ON THE DENSIFICATION AND HYDRATION RESISTANCE OF MAGNESITE– DOLOMITE REFRACTORIES

In this study the effect of nano meter size ZrO۲ particles on the microstructure, densification and hydration resistance of magnesite –dolomite refractories was investigated. ۰, ۲, ۴, ۶ and ۸ wt. % ZrO۲ particles that were added to magnesite –dolomite refractories containing ۳۵ wt. % CaO. The Hydration resistance was measured by change in the weight of specimens after ۷۲ h at ۲۵℃ and ۹۵% relative humidity. The results showed with addition of nano meter size ZrO۲ particles, the lattice constant of CaO increased, and the bulk density and hydration resistance of the specimens increased while apparent porosity decreased. With the addition of small amount ZrO۲ the formation of CaZrO۳ phase facilitated the sintering and the densification process. The mechanism of the nano meter size ZrO۲ particles promoting densification and hydration resistance is decreasing the amount of free CaO in the specimens.

Keywords:

MMagnesite-Dolomite Refractories , Nano Meter Size ZrO۲ , Hydration resistance , Densification