Gypsum is an important renewable resource, containing phosphorus, fluorine and other magazines, the main chemical components are CaO and SO3. gypsum mainly exist in four types of crystalline needles, tabular crystals, dense crystalline, crystal nuclei form. In phosphoric acid production process, part of the phosphate rock is not decomposed, gypsum washing the filtration process is not completely and the addition of additive are all reasons of gypsum containing phosphorus, fluorine and other impurities. gypsum can be used in pharmacy industry.

Gypsum, is solid waste of the fertilizer, phosphoric acid production emissions. With the development of phosphate fertilizer industry in recent years, emissions of gypsum are increased to more than 10 million tons/y of phosphorus. Those large number of discharged gypsum waste, will take up land, cause serious environmental pollution, so reasonable conversion of gypsum resources is seriously and immediately. gypsum mill is important.