Effects of Calcium Zirconate on Properties of Dispersed Gas-permeable Magnesia Refractory

The dispersed gas-permeable magnesia refractories with different calcium zirconate content were prepared by adding calcium zirconate with three methods of in-situ synthesis, direct addition and composite addition with pure magnesia as aggregates. The effects of the addition amount and addition method of calcium zirconate on the performance of the refractories were studied. The results show that with the increase of calcium zirconate amount by direct addition, the gas permeability, apparent porosity and bulk density of the samples increased and the linear shrinkage and strength decreased while the thermal shock resistance first increased and then decreased and reached the highest value with the calcium zirconate addition of 9wt%. Among the three addition methods, the gas permeability, apparent porosity, bulk density and linear shrinkage of the samples by in-situ synthesis were the highest and the strength was the lowest; while the sintering performance of that by composite addition was good and the strength and thermal shock resistance were the highest.