Phosphogypsum, is solid waste of the fertilizer, phosphoric acid production emissions. With the development of phosphate fertilizer industry in recent years, emissions of phosphogypsum are increased to more than 10 million tons/y of phosphorus. Those large number of discharged phosphogypsum waste, will take up land, cause serious environmental pollution, so reasonable conversion of phosphogypsum resources is seriously and immediately. Phosphogypsum mill is important.
First, an overview of phosphogypsum:
Phosphogypsum is an important renewable resource, containing phosphorus, fluorine and other magazines, the main chemical components are CaO and SO3. Phosphogypsum 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, phosphogypsum washing the filtration process is not completely and the addition of additive are all reasons of phosphogypsum containing phosphorus, fluorine and other impurities. Phosphogypsum cannot be directly used for the production of gypsum building materials due to those impurities, pretreatment must be carried out in order to put into use.
Second, phosphogypsum recycling method:
Ways and methods of phosphogypsum recycling are: the produce of construction gypsum powder, gypsum board and gypsum block; as cement retarder, production of cement and sulfuric acid and ammonium sulfate; can be made into paper filler; can be used as soil conditioner in agriculture field. Recently, an innovative of new technology is to extract rare earth elements from phosphogypsum. Poland had reported this technology as early as in the 1990s about extracting rare earths from apatite; and our country carried out a experimental study of launched comprehensive utilization of phosphogypsum and extraction of rare earths, it is learned that this innovative technology can solve three problems once: extracting important rare earth metals from industrial waste, gypsum building materials, and waste recycling.
Third, the development prospects of phosphogypsum
In recent years, the government has increased efforts to promote energy saving, making phosphogypsum recycling and other policy and development opportunities, the world gradually get a better understanding of phosphogypsum, also aware of the harm caused to the environment, increasing of research and development efforts has achieved fruitful results. Phosphogypsum not only can be used in cement, gypsum products, but can also be used to produce potassium sulfate, potassium sulfate, ammonium sulfate and cogeneration and NPK compound fertilizer, and can be used for construction of gypsum-based roads embankment, made RCC construction of parking lots. With the development of science and technology, phosphogypsum has turned into valuable secondary resources in people’s daily life, can promote economic and industry development.