The clay is an important mineral raw materials. The by various hydrated silicate and a certain amount of alumina, alkali metal oxides and alkaline earth metal oxides, and contains quartz, feldspar, mica, and sulfates, sulfides, carbonates and other impurities. Small clay mineral particles in crystalline or amorphous, often in the colloidal size range, most flake, a small number of tubular, rod. Plasticity clay minerals water wet, can be deformed under small pressure and can remain for long, and large specific surface area, with negatively charged particles and therefore have a good physical adsorption and surface chemical activity, with other cations the ability to exchange.