How are silica refractories made from quartzite and silica gravel?

Silica refractories are produced using quartzite and silica gravel deposits that possess low levels of alumina and alkali impurities.1

To manufacture these materials, the raw quartzite is crushed and chemically bonded using 3–3.5 percent lime (often applied as milk of lime). This chemical bonding process is essential for creating the final refractory product, which is valued for its high-temperature load resistance, abrasion resistance, and ability to contain acidic slags.12

Once formed, these bricks are utilized in various industrial applications, including the superstructures of glass-melting furnaces, where high-purity grades are preferred to minimize impurity content.1