Characteristics of high-quality silica brick refractory products

Composition of high-quality silica bricks:

The multiphase structure of squamous quartz, cristobalite quartz, a small amount of residual quartz and glass formed at high temperature is the mineral composition of high-quality silica bricks, and the mineral composition of high-quality silica bricks fluctuates greatly according to the production process and the nature of the raw materials used.

High-quality silica brick is an acid refractory material, which has strong resistance to acid slag or acid melt erosion, but has poor resistance to alkaline material erosion, and is easy to be destroyed by oxides such as Al2O3, K2O, Na2O, etc., and has good corrosion resistance to oxides such as CaO, FeO, and Fe2O3.

The high softening temperature under load is an excellent characteristic of high-quality silica bricks, generally at 1640-1680 °C, which is close to the melting point of squamous quartz (1670 °C) and cristobalite (1713 °C). The volume of silica brick is stable between 300 °C and the melting point (scaly quartz or cristobalite quartz), and when heated to 1450 °C, the volume expansion rate of silica brick is about 1.5%~2.2%, which is conducive to ensuring the structural strength and air tightness of the masonry.

The low refractory degree of high-quality silica brick (generally 1690~1730 °C) is relatively large, and the disadvantage is poor thermal shock resistance (the water cooling cycle is generally 1~4 times), which greatly affects the application range of silica brick.

The performance and process of high-quality silica bricks are closely related to the crystallization transition of SiO2, and the true density of silica bricks is one of the important indicators to judge the crystallization degree of SiO2, so the true density is an important quality index of high-quality silica bricks, which is generally required to be below 2.38/cm3. High-quality silica bricks should be below 2.35g/cm3, and the low true density reflects the high content of scale quartz and gold quartz in the bricks, and the amount of quartz residue is small, so the residual expansion is small, and the strength decreases little in use.

Use of high-quality silica bricks:

High-quality silica bricks are mainly used for laying coking chambers, combustion chambers, coke oven partition walls (about 73% of the refractory materials used in coke ovens are silica bricks), glass pool kilns and kiln roofs, pool walls, hot blast furnaces, carbon roasters and other high-temperature bearing parts of hot kilns. In order to increase the production capacity of modern large-scale coke ovens, thin coke oven carbonization chambers, combustion chambers and partition walls are required, hence the need for high-density, high-thermal conductivity silica bricks. There are many types of high-quality silica bricks, which can be divided into coke oven silica bricks, hot blast furnace silica bricks, electric furnace silica bricks, glass kiln silica bricks, etc. According to the complexity of the bricks, they are divided into standard bricks, general bricks, different bricks and special bricks. Pay attention to Baqiu to learn more about high-quality silica bricks.