基于磷石膏改性的水泥基充填料浆综合性能

Study on Comprehensive Properties of Cement-based Backfill based on Phosphogypsum Modification

这是一篇陶瓷及复合材料领域的论文。为了提高矿物资源综合利用率与充填采矿工艺,以磷石膏、水泥与尾矿砂等矿物固体废料为集料制备矿山充填体材料,开展料浆综合找工作性能、矿物成分与微观形态的分析研究,结合分子动力学模拟对水化物分子结构进行讨论。结果发现:磷石膏的掺入使得水泥基充填料的坍落度显著提高,泌水率下降,抗压强度表现出上升趋势,随养护时间增加,材料强度值显著提高;养护28 d的磷石膏改性充填体的强度值约为水泥基充填的1.2倍;磷石膏改性充填料中的水化硅酸钙与钙矾石为主要水化产物;扫描电子显微镜图像显示磷石膏改性充填料的微观结构较为致密,微裂隙较少;数值模拟结果表明水化硅酸钙的弹性模量明显高于钙矾石,提高充填料强度性能的关键在于促进水化硅酸钙的形成。

This is an article in the field of ceramics and composites.In order to improve the comprehensive utilization of mineral resources and mining technology,mine filling materials are prepared from mineral solid wastes such as phosphogypsum,cement and tailing sands as aggregates,analytical studies of the slurry's comprehensive search performance,mineral composition and microscopic morphology are carried out,and the molecular structure of hydrides is discussed in conjunction with molecular dynamics simulations.The results showed that the addition of phosphogypsum significantly increased the slump of the modified filler,decreased the bleeding rate,and the compressive strength showed a rising trend.The strength value of the modified filler increased significantly with the curing time.The strength of phosphogypsum modified backfill after curing for 28 d is about 1.2 times that of cement backfill.Calcium silicate hydrate and ettringite in phosphogypsum modified filling materials are the main hydration products.SEM image shows that the microstructure of phosphogypsum modified filling materials is relatively compact and there are few micro-cracks.The numerical simulation results show that the elastic modulus of calcium silicate hydrate is higher than that of ettringite.The key to improving the strength of filling material is to promote the formation of calcium silicate hydrate.