磷渣粉改性磷石膏基砂浆机理研究

Mechanism Study on Mortar Based on Phosphorus Slag Powder Modificated Phosphogypsum

以磷建筑石膏为主要原料,研究化工试剂对石膏砂浆工作性能、力学性能和微观性能的影响。采用扫描电镜(SEM)分析微观结构。结果表明,FDN减水剂掺量从0增至1.5‰,石膏砂浆标准稠度从75%减至54%,减水率达28%,石膏砂浆强度在掺量为0.3‰时增加10%;缓凝剂SG-12添加量从0增至0.3%,初凝时间大于100 min,添加量为0.2%时,初凝时间达到40 min以上,可满足砂浆施工要求;改性磷渣粉掺量从0增至15%,石膏砂浆24 h强度出现先升高后下降趋势,当掺量达10%时,磷石膏基砂浆产品抗折强度达到6.2 MPa,比空白组提高138%,抗压强度达到16.3 MPa,比空白组提高90%。由SEM对比分析可知,磷建筑石膏粉添加磷渣复配材料后,磷石膏基砂浆水化后的晶体形貌从原来条状或片状变化为短柱状和中空管状结构,该结构力学性能较未添加磷渣复配材料效果好,有利于磷石膏的综合利用。

In this paper,phosphogypsum was used as the main raw material and the effects of chemical reagents on the working performance,mechanical properties and micro-properties of gypsum mortar were studied.The results showed that the dosage of FDN increased from 0 to 1.5‰,the standard consistency of gypsum mortar decreased from 75%to 54%,the water reduction rate reached 28%,the strength of gypsum mortar increased 10%at the dosage of 0.3‰.The dosage of SG-12 increased decreased from 0 to 0.3%,the initial setting time was greater than 100 min,when the dosage reached 0.2%,the initial setting time reached more than 40 min,which could meet the requirements of mortar construction.When the content of modified phosphorus slag powder increased from 0 to 15%,the 24 h strength of gypsum mortar showed a trend of first increasing and then decreasing.When the dosage reached 10.0%,the flexural strength of phosphogypsum based mortar products reached 6.2 MPa,which was 138%higher than the blank,and the compressive strength reached 16.3 MPa,which was 90%higher than the blank.Through SEM analysis,it was found that the phosphorus slag modified materials was added,the crystal morphology of phosphogypsum based mortar after hydration changed from the original strip or sheet shape to the existing short column and hollow tube structures.The mechanical properties of this structure were better than those of the non added phosphorus slag modified materials,which is conducive to the comprehensive utilization of phosphogypsum.