Silica

Silica (quartzite) quartz as main mineral composition of the siliceous rocks. Manufacture of refractories refractory raw materials. 1820 by the British Young (wwYoun jealous digested first with lime made from silica sand silica, and then with British rock made of silicon silica.
Siliceous refractory silica sand can be used as raw materials for monolithic refractories.
According to the structure of dense silica is generally divided into two types of crystalline silica and silica cementation. Crystalline silica can be divided into veins of quartz and quartzite; cemented with silica quartz sandstone tunnel is divided into Shiyan and so on. By crystal transformation rate can be divided into fast, medium, slow, slow conversion of four special categories.
China Refractory materials zBD53ool at a price of silica quartz is a hexagonal Shao, also known as low-temperature quartz. Quartz is the high temperature quartz. Its crystal transition Fig. The melting point of cristobalite 1713 ℃, tridymite is 1 690 ℃.
Quartz heating process has a volume expansion of the conversion stage. Tridymite which best performance. In a more tridymite the existence of the products to form a strong skeleton. Tridymite easily soluble in the liquid phase, which makes the products, not because of the emergence of a liquid is deformed only when tridymite melted, to make products damage. So close to the softening temperature of the load of silica tridymite melting point. But to make quartz into tridymite mineralizing agent must be added to achieve. When the addition of iron scale (Feo + Fe: Oa) or flat slag can accelerate the transformation, heated to 140. ℃ above conversion intense and accompanied by a large volume expansion (when a mineralization agent), tridymite converted from the quartz, the volume expansion of 12% to 13%, without mineralizing agent, by the quartz British transforming the right volume when the prescription of 17% to 18 expansion write.
China silica rich in resources, mining more, Liaoning, Hebei, Shanxi, Shandong, Henan and other provinces. Silica generated during the grinding dust, easy to make people suffer from silicosis. Fused silica silica brick is mainly used for masonry carbonization chamber coke ovens and glass melting furnace, open-hearth furnace regenerators, etc., in the 1950s and before, are used for open-hearth furnace roof, brick after alkaline replaced.