On the Technical Approach of Greening Phosphogypsum Based Cementitious Materials

磷石膏是湿法工艺生产磷酸过程中产生的固体废弃物，目前，我国每年磷石膏的排放量高达75 Mt，但其利用率仅有40%左右。磷石膏的主要组成为二水硫酸钙，可以替代天然石膏应用于水泥缓凝剂、石膏砌块、石膏板等建筑领域，但由于其本身含有大量磷、氟及有机质等杂质，导致其物理力学性能远低于天然石膏和脱硫石膏，故而难以有效利用，改善其胶凝性能是促进其绿色化资源化利用的关键。本文主要讲述关于磷石膏的结构特性和性能、在建材领域的应用以及其预处理和改性三个方面的研究进展情况。Phosphogypsum is a solid waste produced in the process of phosphoric acid production by wet process. At present, the annual emission of phosphogypsum in China is as high as 75 Mt, but its utilization rate is only about 40%. Phosphogypsum is mainly composed of calcium sulfate dihydrate, which can replace natural gypsum applied in cement retarder, gypsum block, gypsum board and other construction fields, but because it contains a lot of phosphorus, fluorine and organic matter and other impurities, resulting in its physical and mechanical properties are far lower than natural gypsum and desulphurized gypsum, so it is difficult to effectively use, improving the gaging performance is the key to promote its green resource utilization. In this paper, the structural characteristics and properties of phosphogypsum, its application in building materials, and its pretreatment and modification are discussed.