半水磷石膏参与固化原状磷石膏制备复合胶凝材料

利用半水磷石膏（HPG）协同灰钙粉和水泥固化原状磷石膏（RPG）制备磷石膏基复合胶凝材料（PBCM）。采用单因素实验探究了HPG掺量对PBCM浆体性能的影响,并通过正交实验进一步探究各掺合料对PBCM强度及耐水性的影响。结果表明：HPG可作为RPG的固化材料,既高效又环保,掺量在20%（质量分数,下同）以上的HPG可彻底解决PBCM浆体的泌水问题,显著缩短浆体凝结时间,掺量在40%以上的HPG可有效改善浆体流动性;HPG、灰钙粉和水泥可有效提高PBCM强度,其中水泥对耐水性影响显著。微观形貌分析显示,PBCM的主要水化物二水硫酸钙和钙矾石晶体交织生长于RPG晶体之间,从而实现了对RPG的有效固化。

Hemihydrate phosphogypsum as used to solidify the raw phosphogypsum to prepare composite cementitious material

The phosphogypsum-based composite cementitious material（PBCM）was prepared by using hemihydrate phospho-gypsum（HPG）with ash calcium powder and cement to solidify the raw phosphogypsum（RPG）.The single factor experiments was carried out to investigate the influence of HPG content on PBCM slurry performance,and the effects of various admixtures on the strength and water resistance of PBCM were further explored through orthogonal experiments.The results showed that HPG was an effective and environmental solidification material for RPG,more than 20%（mass fraction）of HPG could com-pletely solve the bleeding problem and significantly shorten the setting time of PBCM slurry.The slurry fluidity was effectively improved by more than 40%（mass fraction）of HPG.The HPG,ash calcium powder and cement could effectively improve the strength of PBCM.The effect of cement on water resistance was significant.Microscopic analysis was revealed that the main hydrates of PBCM were CaSO₄·2H₂O and ettringite,which were interweaved with each other and grow between the RPG crystals,so as to realize the effective solidification of RPG.