A systematic review of cemented paste backfill technology for cleaner and efficient utilization of phosphogypsum in China

Abstract

Utilization of phosphogypsum (PG) with cleaner and efficient approach has always been a global challenge. Cemented PG backfill (CPGB) technology uses a cleaner filling material mixed with a large amount of PG to support the surrounding rock of mine goaf, which not only can efficiently solve the environmental problems during PG stacking, but also can suppress the goaf collapse. After more than 20 years of development, China has now become most popular country in CPGB technology research. This paper provided the first systematic overview of the recent research of CPGB in China in terms of cemented PG filling materials (CPGFM), environmental impacts, case studies, and challenges and prospects. Firstly, the preparation of CPGFM was introduced around the role of PG in the CPGFM, and the influencing factors and control measures of CPGFM performance were elaborated. Then, the highly anticipated environmental impacts of CPGFM were summarized based on hazardous gases emissions, phosphate and fluoride leaching and control measures. Subsequently, three engineering cases corresponding to PG utilization methods were presented. Finally, the challenges and prospects of CPGB were discussed. The results show that the use of PG as aggregate in CPGFM is an effective way to quickly reduce the stockpiles. The risk of secondary release of fluoride in various pollutants needs to be strengthened control. The existing pollutant control methods mostly use acid-base neutralization method. This comprehensive review of CPGB in China can provide valuable reference for cleaner and efficient utilization of PG worldwide.