Effects of different treatment of phosphogypsum on properties of cement mortar

In this paper, the effects of the phosphogypsum (PG) content at 0%–50% and the calcination at 750°C, 800°C, and 850°C on the properties of cement mortar were studied. It is observed that the optimal mechanical properties of cement mortar are achieved when the PG content is 30% and calcined at a temperature of 800°C. Building upon these findings, further investigations were conducted to explore the effect of 0%–5% quicklime aging treatment combined with calcination on the properties of cement mortar. The results show that the samples prepared with PG aging with 2% lime and calcined at 800°C exhibit the best mechanical properties. In addition, it is revealed that the mechanical strength shows similar trends compared to the activation index for PG cement mortar. Physical properties tests and microstructure observation indicate that combining calcination with quicklime modification represents an effective approach to the use of PG in the field of building materials.