磷石膏粒径及pH值对其复合胶凝材料的影响

摘要

利用大宗工业固体废物二水磷石膏和粉煤灰，加入少量水泥、生石灰等原料制备磷石膏基复合胶凝材料，研究了磷石膏的粒径以及pH值对胶凝材料凝结时间、强度的影响规律，采用SEM、XRD等测试方法对胶凝材料的水化产物、微观结构进行分析。结果表明：适当减小磷石膏粒径或增加磷石膏pH值，都会降低磷石膏基胶凝材料的用水量，缩短凝结时间，提高强度，并且通过蒸汽养护，最终可制备出28 d强度超过40 MPa，软化系数接近0.9的胶凝材料。%Composite binders based on phosphogypsum(PFLC) were made from phosphogypsum, lfy ash, cement, lime. The inlfuences of the particle size and pH value of phosphogypsum on the setting time and strength of the PFLC were researched. And through XRD, SEM, we studied the hydration products and microstructure on PFLC. The experimental results show that the water dosage, the setting time of PFLC can be reduced and the strength can be improved by appropriately decreasing the particle size or increasing the pH value of phosphorus gypsum.When the particle size of phosphorus gypsum is between 25~20μm and the pH value is greater than 5, compounding lfy ash, cement, lime, by steamcuring, we can prepare composite binders which the compressive strength is higher than 40 MPa at 28 d and the softening coefifcient is close to 0.9.