磷石膏-水泥基复合充填材料的综合性能和细观水化机理

Comprehensive Performance and Microscopic Hydration Mechanism of Phosphogypsum-Cement Based Composite Filling Material

为提高矿山充填膏体的性能与环保效益,采用磷石膏-水泥复合胶凝剂制备了胶结充填膏体,分析了坍落度、干燥收缩率、渗透系数与强度等指标受胶凝剂配比和骨料性质的影响规律,并对充填膏体的细观水化机理进行了分析。结果表明:磷石膏-水泥胶凝剂对充填膏体流动性、收缩性和强度均有改良效果;磷石膏掺量是影响膏体性能的重要因素,当磷石膏掺量为20%时,充填膏体抗压、抗折强度最高,渗透率和收缩率最低,耐久性最好;一定比例的含钢渣粗骨料可以增加磷石膏-水泥基充填膏体的强度;磷石膏具有较好的化学活性,在反应过程中促进了絮凝状胶凝产物的形成,在细观上提高了膏体密实度,增强了矿山充填膏体的综合性能。利用磷石膏-水泥基充填膏体实施自流充填采矿工艺,不仅有利于节约开采成本,还实现了磷石膏的资源化利用,在绿色矿山建设中具有广阔的应用前景。

In order to improve the performance and environmental benefits of mine filling paste,the cemented filling paste was prepared by using phosphogypsum-cement composite gelling agent.The influences of gelling agent ratio and aggregate properties on slump,drying shrinkage,permeability coefficient and strength were analyzed.The microscopic hydration mechanism of filling paste was analyzed.The results show that the phosphogypsum-cement gelling agent has an improved effect on the fluidity,shrinkage and strength of the filling paste.The content of phosphogypsum is an important factor affecting the performance of the paste.When the content of phosphogypsum is 20%,the compressive strength and flexural strength of the filling paste are the highest,the permeability and shrinkage are the lowest,and the durability is the best.A certain proportion of coarse aggregate containing steel slag can increase the strength of phosphogypsum-cement based filling paste.Phosphogypsum has a good chemical activity,which promotes the formation of flocculated gelling products during the reaction process,improves the density of paste at the meso level,and enhances the comprehensive performance of mine filling paste.Using phosphogypsum-cement based filling paste to implement gravity filling mining technology is not only conducive to saving mining costs,but also realizes the resource utilization of phosphogypsum,which has broad application prospects in the construction of green mines.