Preparation and characterization of phosphogypsum based type II anhydrous calcium sulfate cementitious material
CAO Hong1， WANG Haiyang1， WU Jing2， LI Lei1， MA Huijuan3， XUE Jun1， JIANG Jizhou1
(1.School of Materials Science and Engineering， School of Environmental Ecology and Biological Engineering， Novel Catalytic Materials of Hubei Engineering Research Center， Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education， Wuhan 430205， China； 2. Key Laboratory of Rare Mineral， Ministry of Natural Resources， Geological Experimental Testing Center of Hubei Province， Wuhan， 430034， China； 3. Hubei Three Gorges Laboratory， Yichang， 443000， Hubei， China)
Abstract：Large-scale non-hazardous and resourceful utilization of phosphogypsum is crucial for addressing the “three phosphorus” issues， promoting the reduction and emission mitigation of phosphogypsum at the source， and facilitating the green development of the phosphorus chemical industry. The development of Type II anhydrous calcium sulfate gelling materials can effectively broaden the application fields and scale of phosphogypsum， thereby accelerating the resolution of phosphogypsum-related issues. Using phosphogypsum-based Type II anhydrous calcium sulfate as the primary raw material， and through extreme vertices design experiments， the relationship between raw material proportions and the properties of gelling materials was explored. Cementitious materials with a softening coefficient of at least 0.8 and strength levels such as A40， A30， and A20 were generated， and phosphogypsum-based type II anhydrous calcium sulfate cementitious materials apt for various application contexts were prepared. The P and F acids in the leachate of the cement-based materials were assessed against national norms， and the results showed that both indicators were below the pollutant concentration control standards for Class I general industrial solid waste specified in GB 18599—2020. Therefore， phosphogypsum-anhydrite-hydrate (PAH) gelling materials could be used as filling and cementing materials for mine shafts (pits)， as well as cementing materials for outdoor and general building materials， offering more possibilities for expanding the green application scenarios of phosphogypsum and potentially increasing its utilization volume.
2025, Vol. 59 
