为探究柠檬酸水溶液预处理磷石膏作为充填体材料的可行性，试验采用质量浓度为4%的柠檬酸水溶液对磷石膏进行浸泡预处理，将处理后的磷石膏与未处理的磷石膏分别制备成6种不同配比的试样，先后对标准养护条件下的样本进行了剪切流变测试，7 d、14 d和28 d的单轴抗压强度测试，以及扫描电镜（SEM）测试。试验结果表明：柠檬酸浸法预处理磷石膏充填体较未处理磷石膏充填体单轴抗压强度明显提高，且主要强度形成期在0~7 d，同时，预处理磷石膏可以降低浆体屈服应力，提高浆体易泵性；SEM结果显示，预处理磷石膏充填体的微观结构与未处理磷石膏相比其标志性水化产物的产生量更多，微观结构更加致密。

In order to explore the feasibility of citric acid Immersing pre-treated phosphogypsum as the cemented paste backfill material,the phosphogypsum was pretreated with citric acid aqueous solution with a mass concentration of 4%. The treated phosphogypsum and the untreated phosphogypsum were respectively prepared into cemented backfill test pieces having a mass concentration of 62% and 64% and a lime-sand ratio of 1∶7，1∶9 and 1∶11. The samples under standard curing conditions were subjected to shear rheology tests，uniaxial compressive strength（UCS） tests at 7 d，14 d，and 28 d，and scanning electron microscopy （SEM）tests. The experimental results show that the uniaxial compressive strength of the pre-treated phosphogypsum filling body is significantly higher than that of the untreated phosphogypsum filling body，and the main strength formation period is 0~7 d. At the same time，the pretreatment of phosphogypsum can reduce the yield stress of the slurry. The SEM results show that the microstructure of the pretreated phosphogypsum filling body is more than that of the untreated phosphogypsum，and the microstructure is more compact. Based on the above research，the use of citric acid leaching to pretreat phosphogypsum in practical industrial applications can greatly reduce the amount of cementitious materials，and improve the slurry transport performance and thus significantly reduce the filling cost，but specific industrial applications need further exploration.