Zircon is the main component of refractories. It contains 67.23% zirconia and 32.77% silicon oxide. Orthorhombic, usually tetragonal. The coefficient of expansion is 4.2 × 10-6 / ℃ at 20-1000 ℃. Melting point 2430 ℃. The bulk density is 3.60-4.3g/cm3. The apparent porosity was 0% ~ 18%. Load softening temperature > 1550 ℃. It is made by semi dry pressing and calcining at 1600 ℃. It is mainly used for lining of steel drum and sizing nozzle for continuous steel injection.