The comprehensive disposal and resource utilization of phosphogypsum has always been a worldwide problem. Most foreign countries also treat phosphogypsum mainly in storage. At present, there are huge phosphogypsum storage yards in more than 50 countries including the United States, France, Brazil, and Australia. Among many developed countries, Japan is one of the more advanced countries in the comprehensive utilization of phosphogypsum. Due to the shortage of phosphate rock resources in Japan and the low production capacity of phosphate fertilizers, the rational use of phosphate rock is fully considered when designing the phosphoric acid process, and higher quality phosphogypsum can finally be obtained. The utilization rate of phosphogypsum in Japan is as high as 90%, and 75% of the phosphogypsum is used to produce building materials such as gypsum board and plaster powder.

 

China is a large agricultural country and the world's largest producer of phosphate fertilizers. The emissions of phosphate fertilizer by-product phosphogypsum ranks first in the world. At present, the amount of phosphogypsum stacked in China has reached more than 600 million tons. It is still growing at a rate of more than 70 million tons per year. China's phosphoric acid production enterprises and scientific research institutions.


        A lot of research and production practices have been done in the field of comprehensive utilization of phosphogypsum, and the finished products include water Mud retarder, β-building gypsum powder, paper-faced gypsum board, gypsum block, plastering mortar, self-leveling mortar, etc. The use of phosphogypsum in the field of building materials is the main way for China to absorb phosphogypsum in addition to storage and disposal . Facing industry problems such as the lack of phosphorus-rich resources and the backward technology of phosphogypsum utilization, phosphogypsum upstream and downstream enterprises have strengthened scientific research and industrial chain extension, increased the added value of products, and improved resource utilization efficiency; the government has also successively formulated guiding policies and guidelines Enterprises have refined plans for the discharge of phosphogypsum, and actively cultivated demonstration enterprises, which promoted advanced and applicable large-scale use. The development and application of comprehensive utilization technology of high-quality and high-value phosphogypsum.

 

The production method of cement retarder made from phosphogypsum is as follows: transport phosphogypsum to the raw material storage shed, transport the phosphogypsum and calcium carbide slag to the granulation equipment for mixing and granulation through metering and mixing. Enter the steam curing kettle for 2 to 3 hours of steam curing. After the steam curing is completed, the material is transferred to the maturing shed through the belt, and the material is matured in the maturing shed for about 7 days. After the maturation, the material is a qualified cement retarder. It can completely replace natural gypsum and desulfurized gypsum.