Silica refractory materials refer to refractory materials with over 93% silicon dioxide (SiO?) content. They are the primary raw materials for acid refractory materials, with the main product being fired silica bricks, although there are also loose materials.

Silica bricks mainly consist of tridymite, cristobalite, residual quartz, and glassy phase. During production, a small amount of lime and iron phosphate is added as a flux to promote the transformation of quartz into tridymite in the body. The bricks are typically fired slowly at temperatures between 1350 and 1430 degrees Celsius in a reducing atmosphere. During the firing process, the quartz in the body first transforms from the low-temperature form to the high-temperature form, and then into cristobalite and tridymite. Upon cooling, the cristobalite and tridymite also transform from their high-temperature forms to the low-temperature forms. The crystalline transformations during silica brick production also cause the true specific gravity to decrease from around 2.65 to between 2.23 and 2.42, depending on the degree of quartz transformation, while also causing volume expansion.

Silica bricks are acid refractory materials with strong resistance to acids and slags. They have excellent high-temperature strength, with a load-softening temperature close to their refractoriness, generally between 1620 and 1660 degrees Celsius. They have the advantage of not deforming during long-term use at high temperatures. Above 600 degrees Celsius, silica bricks generally do not undergo crystalline transformations, have a low coefficient of expansion, and exhibit good thermal shock resistance. Below 600 degrees Celsius, the properties are the opposite. They are mainly used for constructing coke ovens and are also used in the arches and other load-bearing parts of various glass, ceramic, and refractory material kilns. They are also used in the high-temperature bearing parts of hot blast stoves but are not suitable for thermal equipment with temperature fluctuations below 600 degrees Celsius.