The performance requirements of silica bricks, the appearance of silica bricks are stipulated in the standard as follows: cracks are allowed to cross one edge, and special-shaped and special-shaped bricks with a side width of less than 50mm are allowed to cross two edges. Two points should be paid attention to when using silica bricks: when the silica bricks are at 200~300°C and 573°C, the volume expands suddenly due to the transformation of the crystal form. Severe temperature changes should be avoided.

Silica brick is a refractory product with SiO2 as the main component. Its SiO2 content is generally not less than 93%. Silica brick is an acidic refractory material with strong resistance to acidic slag and good resistance to CaO, FeO, Fe2O3 and other oxides, but poor resistance to alkaline slag erosion, and is easily oxidized by Al2O3, K2O, Na2O, etc. destruction by the action of things. The softening temperature of silica brick under load is as high as 1640~168O℃, and the volume is relatively stable in long-term use at high temperature. However, the thermal shock resistance of silica brick is poor, and the refractoriness is not high enough.

The main component of silica brick is SiO2. SiO2 has 7 variants and 1 phenanthrene crystal variant under normal pressure, namely β-quartz, α-quartz, γ-tridymite, β-tridymite, α-tridymite, β-cristobalite, α-cristobalite and quartz glass. The properties of its variants are shown in the table below. 
SiO2 undergoes crystal transformation when heated, and its process, temperature and volume changes are shown in the following figure.
 
The production process of silica brick is shown in the figure below.