Study on physical and chemical characteristics of β-hemihydrate phosphogypsum
Xuemei Chen, Yuanzheng Liu, Qihong Wu, Yi Ding, Qingyuan Wang, Wenjie Tang, Baiyu Zhu
Abstract
Calcium sulfate hemihydrate is the most widely used binder for gypsum-based materials. This paper investigates the physical and chemical characteristics of β-hemihydrate phosphogypsum aiming to promote the utilization of phosphogypsum on a large scale. A comparative study of HPG, HFG and HNG based on particle characteristics, composition analysis, hydration characteristics, microstructure, and compatibility with admixtures was performed. The results show that the acidic hydration environment and co-crystallized phosphate are particular for HPG. The optimal admixtures for HPG are protein retarder and polycarboxylate superplasticizer. Besides, an increase in HPG particle fineness would promote hydration and improve mechanical strength in the presence of a water reducer. The comparable strength and the same hydration mechanism support that HPG is a competitive binder with HFG and HNG. These findings are desirable for industrial application.