Aluminum (Al) is a light metal, and its compounds are widely distributed in nature. The resources of aluminum in the crust are about 40~50 billion tons, ranking third only after oxygen and silicon. It is the first major metal category among metal varieties. Aluminum has special chemical and physical properties. It is not only light in weight and hard in texture, but also has good ductility, conductivity, thermal conductivity, heat resistance and nuclear radiation resistance. It is an important basic raw material for national economic development.