Jewel

A high-quality hard refractory clay produced in Zhangqiu, Shandong, China. The standard coke gem ore contains 38% Al2O3, about 45% Al2O3 after calcination, Fe2O3 < 0.8%, and its bulk density is not less than 2.55-2.58 g/cm3.

Another: K2O+Na2O+CaO+MgO:0.5 ~ 1% below. It has stable composition, uniform texture, compact structure, shell-like section and white color. It is used to produce high-quality clay refractories. The technical term is first-class hard clay clinker, the main chemical composition is AL2O3 and SiO 2, accompanied by a small amount of Fe2O3 and trace Na2O, K2O, the main mineral is kaolin. Generally calcined as raw material for common ceramic fibers.