磷建筑石膏的特性及其改性

磷建筑石膏在组成和结构上与天然建筑石膏不同,对其加以改性后能更好地代替天然建筑石膏使用。采用激光粒度分析仪和扫描电子显微镜,结合物理力学性能测试发现磷建筑石膏颗粒分布集中,平均粒径约为30μm,晶体多呈板柱状;浆体显酸性,初凝时间短,标准稠度需水量大,性能波动不定。在生产磷建筑石膏时,通过粉磨改性控制其比表面积在3500～4500 cm2/g;通过添加Ca(OH)2调整浆体的pH值;加缓凝剂对凝结时间加以改性,但需要调整浆体的pH值。

Research on Characteristics of Phosphorus Building Gypsum and Its Modification

The composition and structure of phosphorus building gypsum are significantly different with that of natural gypsum so it will better replace the natural gypsum when it is modified.The performance of phosphorous building gypsum and its modification were investigated with a laser apparatus for particle measurement and SEM.Experimental results showed the particle size distribution of phosphorus building gypsum is concentrate,its average size is about 30 μm,its crystals display lath shaped or prismatic shaped,its paste pH value is acidity,its initial setting time is shorter,the water demand of standard consistency is higher and its property is not steady.Grinding phosphorus building gypsum with the specific surface area of 3500-4500 cm2/g when it was produced and adjusting the slurry pH value can improve its physical and mechanical properties.Retarders used in phosphorus building gypsum has a certain pH value scope.