Zircon is chemically inert with good erosion resistance to high temperature molten glass and slag solution. High dense zircon brick made of zircon powder as the main raw material has good high temperature strength and strong resistance to glass liquid, so it is widely used as the bottom paving block and back lining structure in the glass furnaces and the lining of the glass furnaces for producing glass fiber. 

During the use, some parts of the glass furnace are required to have good thermal shock resistance. Since the thermal shock stability of the dense zircon brick is bad, it reduces the service life of glass furnaces and increases the repair cost of glass furnaces. 

Zircon can improve the properties of dense zircon brick. The dense zircon brick is made of zircon powder by adding high pure industrial zirconia, fused stabilized zirconia and desilicated zirconia. After Formulating according to the amount of the added zirconia, wet-mixing, spray granulation, isostatic pressing and sintering at 1530 ℃ and 12h insulation, 69% dense zircon brick is made. 

Research about these three different samples of zirconia on the apparent porosity, bulk density, firing shrinkage and thermal shock stability and a scanning electron microscope (SEM) on the microstructure and fracture surface samples are carried out. 

The results showed that: compared to 65 dense zircon brick without ZrO2 added, the samples with ZrO2 added have higher apparent porosity, bulk density, firing shrinkage and thermal shock stability.