Anhydrous sodium sulfate, whose mineral form is Thénardite, is also called sodium sulfate when it is highpurity and fine particle, and is a crystal composed of rhombic crystal system. It is widely used in various industrial fields: as a cooking agent for kraft pulp in the papermaking industry; Replacing soda ash in the glass industry; In the chemical industry, it is used to manufacture Sodium sulfide and Sodium metasilicate; Serve as a dyeing aid in the dye industry, etc.