Silica brick is a refractory material with SiO2 content of more than 93%. It is made of quartz (silica) as raw material, crushed to the appropriate particle size, and then added to an appropriate amount of binder (such as lime) and mineralizer (such as iron powder to promote the formation of quartz), after mixed forming dry blasting and heating up as planned and fired.

(1) Introduction of silicon brick characteristics

1. The chemical composition of silica brick varies with different silica raw materials. In general, the content of SiO2 is 93%~98%, and other impurities, such as SiO2Fe203 and CaO, are 2.0%~7.0%.

2. The mineral composition of silica brick, ordinary silica brick is dominated by scale quartz, accounting for 30%~70%; The high silica and high-density silica bricks mainly consist of square quartz, accounting for 20%~80%. Residual quartz and amorphous quartz glass are in small quantities in any silica brick.

3. Silica brick refractoriness, mainly depends on SO2 content and impurity content, and its nature. The higher the sO2 content, the less the impurity content, and the closer the refractoriness is to the melting point of dry SiO2: on the contrary, the lower the refractoriness is, the refractoriness of silica brick is generally 1690~1730℃.

4. Although there are some impurities, the mass melting point is low, but the dry skeleton has a certain bearing capacity, so its load softening temperature is close to its refractoriness, which is a significant characteristic of silicon brick.

5. Slag resistance of silica brick. The main chemical composition of silica brick is curved acid oxide Si02, which determines its strong resistance to acid slag. At the same time, Fe203, CaO, and SiO2 can form new compounds, so the silica brick still has a certain resistance to the alkaline oxides Fe203 and CaO in the slag.

6. The smaller the true density, the better. The smaller the true density means that the quartz transformation is complete, and the residual expansion generated in the actual use is small.

7. Porosity of silica brick indicates the density of silica brick. The smaller the porosity, the denser the structure. The apparent porosity of silica brick is generally 21%~25%. The size of porosity, in addition to raw materials mainly depends on its technological conditions.

8. Residual expansion of silica brick refers to the irreversible volume expansion of silica brick after re-forging and firing, which is called the residual expansion of brick. The reason is that there is still unconverted quartz in dry silica brick or residual quartz continues to transform. The smaller the residual expansion of silicon brick, the better, otherwise when used in the kiln, it will be caused by its excessive expansion

The destruction of the structure of the empty furnace causes the accident. The silicon brick with low true density has a small residual expansion. The size of residual expansion of silica brick is mainly determined by dry firing conditions. When silica brick is burned to 1450℃ and kept warm, the residual expansion is generally 0.3%~0.8%.

9. The bed strength of silicon brick at room temperature is mainly used to determine the advantages and disadvantages of silicon brick structure. Room temperature bed strength size, often with porosity, and true density are closely related. It also depends on the nature of raw materials and technological conditions. The compressive strength of silicon brick is 19.6~29.4MPa at normal temperature.