Explanation

It is customarily called kaolin or kaolinite clay. It is clay specially used for firing ceramics. The mineral composition is mainly kadinite. It is white and can appear gray white, gray, gray yellow, yellow brown, gray green, and gray black when containing impurities. It is earthy or dense block, with a hardness of 1-2.5. It has a clear sense of smoothness when touched by hand. Its density is 2.2-2.6g/Cm3, and it feels sticky when licked with tongue when dry. It has strong water absorption, but does not expand. After being crushed into powder and mixed with water, it has plasticity, insulation and high refractoriness. Its chemical properties are relatively stable and its acid resistance is also good. Chemical composition is an important factor to evaluate the quality of kaolin. The higher the content of Al2 () 3, the higher the refractoriness, and the better the hardness of the product. Many impurities will seriously affect the quality of kaolin, Mainly distributed in the southeastern coastal areas, there are also weathering type kaolin deposits in southern Sichuan, northern Guizhou, western Yunnan, central Hubei, and other places. Sedimentary type is the main type of deposit, followed by hydrothermal type kaolin deposits. The kaolin deposit in Jingdezhen, a famous porcelain capital in China, is a weathering residual type deposit. In addition to being used as raw material for ceramics, kaolin is also a filler for paper making, rubber and plastics. In medicine, kaolin is called Baishizhi. It has a flat nature, and can cure jaundice, diarrhea, and pathogenic carbuncle.

Classification