磷石膏基充填胶凝材料配方优选及水化机理  

Formulation Optimization and Hydration Mechanism of Phosphogypsum-based Filling Cementitious Materials

作　　者：杨晨 贾永祥 杨啸 吕亚军[1] YANG Chen;JIA Yongxiang;YANG Xiao;LYU Yajun(North China University of Water Resources and Electric Power,Zhengzhou 450046,China)

机构地区：[1]华北水利水电大学,河南郑州450046

出　　处：《华北水利水电大学学报（自然科学版）》2024年第5期100-108,共9页Journal of North China University of Water Resources and Electric Power：Natural Science Edition

基　　金：国家重点研发计划项目(2022YFC3202504);河南省高校科技创新人才支持计划项目(21HASTIT010);河南省重点研发与推广专项(科技攻关)(232102321107)。

摘　　要：磷石膏是湿法磷酸工艺中产生的固体废弃物,其活性很低,是一种无害化处理难度较大的废弃物。酒泉钢铁公司炼铁过程中产生的矿渣具有较高的活性,可以与磷石膏混合制备具有胶凝性质的材料,对采空区进行回填来消除采空区地质灾害。根据不同配比和不同磷石膏细度下充填胶凝材料强度的正交试验,得出磷石膏基充填胶凝材料的最优配方,在此基础上使用扫描电子显微镜(SEM)和X射线衍射(XRD)分析其内部结构。结果表明:在生石灰含量5.5%~6.0%、磷石膏含量30.0%~33.0%、NaOH含量1.5%~2.0%,芒硝含量2.5%~3.0%,矿渣平均粒径为15.88μm,添加助磨剂和早强剂的情况下,充填胶凝材料的3 d和7 d抗压强度分别达到1.58 MPa和4.10 MPa。水化硅酸钙凝胶和钙矾石的生成量随着龄期的增长逐渐增加,结构逐渐密实,水化硅酸钙凝胶在充填胶凝材料中起到了充填黏结作用,钙矾石在充填胶凝材料中起到了支撑作用,从而提高了材料的整体强度。Phosphogypsum is a solid waste byproduct produced in the wet phosphoric acid process,characterized by low reactivity and is a waste that is difficult to treat harmlessly.The slag produced in the ironmaking process of Jiuquan Iron and Steel Company has high reactivity,which can be mixed with phosphogypsum to prepare cementitious materials suitable for filling abandoned mining voids,thus mitigating geological hazards associated with subsidence.The optimum formula of phosphogypsum based filling cementing materials was obtained by orthogonal experiment of filling cementing material strength under different ratio and fineness.On this basis,scanning electron microscopy(SEM)and X-ray diffraction(XRD)were applied to analyze the internal structure.The results are as follows.The average particle size of slag is 15.88μm,with a quicklime content of 5.5%~6.0%,a phosphogypsum content of 30%~33%,a NaOH content of 1.5%~2.0%,and a mirabilite content of 2.5%~3.0%.With the addition of grinding aids and early strength agents,the 3 d and 7 d strength of the filled cementing material reached 1.58 MPa and 4.10 MPa,respectively.The amount of hydrated calcium silicate gel and ettringite increased gradually with the growth of age,and the structure was gradually dense.The hydrated calcium silicate gel plays a filling and bonding role in the filling cement material,and ettringite plays a supporting role in the filling cement material,thus improving the overall strength of the material.

关 键 词：采空区 磷石膏 矿渣 固体废弃物 水化机理 抗压强度 

分 类 号：TU502.6[建筑科学—建筑技术科学]