The production line of kaolin produced by calcining gangue, built by Zhengzhou Jiutian, was officially put into operation in Russia. Gangue is a solid waste produced in the process of coal mining. The production of kaolin from gangue requires processes such as proportioning, grinding, calcination, and purification. The pre-treated kaolin enters the rotary kiln for deep processing at high temperature. The crystals undergo physical changes due to heat, and the structure is rearranged, eventually becoming ultra-fine calcined kaolin. Making kaolin from gangue is actually a process of turning waste into treasure. It is widely used in ceramics, papermaking, coatings and other industries.