Improved Refractory Aluminosilicate Bricks Through Nano Zirconia Additions

The physico-mechanical and refractory properties of refractory bricks, prepared from 50 wt.% kaolin and 50 wt.% alumina, were improved through the addition of different contents (2, 4, 6, 8 and 10 wt. %) of nano zirconia powder. The densification parameters (bulk density and apparent porosity), mechanical properties (cold crushing strength) and refractory properties (thermal shock resistance) were tested for the prepared refractory bricks fired at 1500 oC. The mineralogical composition of the prepared zirconia and the refractory bricks were followed by X-ray diffraction analysis (XRD) whereas while their microstructure and chemical constituents were depicted using scanning electron microscope attached with energy dispersive x-ray unit (SEM + EDAX). The refractory brick samples containing 8 wt. % of nano zirconia was considered as the optimum among the investigated samples as it shows the best sintering, mechanical and refractory properties, these were correlated with their recognized assemblage of minerals; mullite-cristobalite-zirconia