Bentonite (Bentonite) is a water bearing clay mineral dominated by montmorillonite. The chemical composition of montmorillonite is: (Al2, Mg3) Si4O10 OH2. NH2O, because of its special properties. Such as swelling, caking, adsorption, catalysis, thixotropy, suspension and cation exchange. So it is widely used in various industrial fields. The montmorillonite structure of bentonite is a 2:1 type crystal structure consisting of two silica tetrahedrons and a layer of alumina octahedron. Some cations, such as Cu, Mg, Na, K, exist in the layered structure formed by the montmorillonite cell, and the interaction between these cations and the montmorillonite cell is very unstable and easy to be exchanged by other cations. It has better ion exchange property. Overseas, it has been applied in more than 100 departments in 24 fields of industry and agriculture, with more than 300 products. Therefore, it is called "universal soil".