不同细度和煅烧温度下磷石膏的基本性能及砂浆强度研究

Study of properties of phosphogypsum and phosphogypsum mortar strength under different fineness and calcination temperature

为在建筑行业中大量地使用湿法磷酸生产过程中产生的磷石膏,通过球磨、筛选不同细度的磷石膏,采用TG/SEM等技术,研究不同煅烧温度对磷石膏性能及微观结构的影响,并分析不同煅烧温度对磷石膏砂浆强度的影响。结果表明:磷石膏存在典型的结晶水和共晶磷,微观形貌主要以菱片状和板片状为主,目数越大,颗粒尺寸越小,厚度也越薄。经过高温煅烧后,二水磷石膏向半水石膏和硬石膏转化,温度越高,转化效果越明显,共晶磷的去除越显著,比表面积越大。磷石膏颗粒的最大厚度和径厚比分别为2.56μm和13.993,纯磷石膏砂浆养护90 d时的最大抗折强度和抗压强度分别为1.23 MPa和23.1 MPa。因此,磷石膏砂浆可用于承载力要求为C20的墙体和梁以及非承重填充墙、抹灰等工程。

In order to popularize the use of phosphogypsum produced in the production of wet process phosphoric acid in the construction industry,phosphogypsum with different fineness was selected by ball milling.The effects of different calcination temperatures on the properties and microstructure of phosphogypsum were studied by TG/SEM,and the effects of different calcination temperatures on the strength of phosphogypsum mortar were analyzed.The results show that there are typical crystalline water and eutectic phosphorus in phosphogypsum.The micro morphology is mainly rhombic and plate.The larger the mesh number,the smaller the particle size and the thinner the thickness.After high temperature calcination,dihydrate phosphogypsum is transformed into hemihydrate gypsum and anhydrite.The higher the temperature,the more obvious the transformation effect,the more significant the removal of eutectic phosphorus and the larger the specific surface area.The maximum thickness and diameter thickness ratio of phosphogypsum particles are respectively 2.56μm and 13.993.The maximum flexural strength and compressive strength of pure phosphogypsum mortar cured for 90 days are 1.23 MPa and 23.1 MPa respectively.Therefore,phosphogypsum mortar can be used for walls and beams with bearing capacity of C20,non bearing infilled walls,plastering and other works.