磷石膏—矿渣复合胶凝材料配比优化试验

Optimization Test of the Proportion of Phosphogypsum-slag Composite Cementitious Material

针对金川矿山充填采用水泥作为胶凝材料成本较高的问题,利用当地固体废弃物资源开发矿用新型胶凝材料。首先对试验材料进行物化分析,开展了磷石膏—矿渣复合胶凝材料强度正交试验,并在此基础上进行磷石膏—矿渣复合胶凝材料配比优化试验确定最优配比;然后对磷石膏—矿渣复合胶凝材料强度的影响因素进行了分析,利用扫描电镜观察了各龄期水化产物的微观结构,并对磷石膏—矿渣复合胶凝材料成本进行了核算。研究表明:磷石膏—矿渣复合胶凝材料早期强度较低,而后期强度较高;磷石膏—矿渣复合胶凝材料配比优化试验确定最优配比为生石灰7%、磷石膏30%、芒硝2%和矿渣微粉61%;SEM观察到水化产物以钙矾石和C—S—H凝胶为主,并且随着养护龄期的增长,结构不断紧密,强度不断提高;对磷石膏—矿渣复合胶凝材料最优配比进行成本核算,得出其成本为180元/t,与金川矿山专用的38.5非标水泥成本相比,胶凝材料成本降低了44%;对复合胶凝材料充填料浆管输特性进行了测定,结果满足金川矿山自流输送要求。

In view of the high cost of using cement as cementitious material for filling in Jinchuan Mine,new cementitious materials for mining are developed by utilizing local solid waste resources.Firstly,the physical and chemical analysis of the test materials is carried out,the orthogonal test of the strength of phosphogypsum-slag composite cementitious materials is done,and on this basis,the optimum proportion of phosphogypsum-slag composite cementitious materials is determined by the optimum test.Then,the factors affecting the strength of phosphogypsum-slag composite cementitious materials are analyzed,the microstructure of hydration products at different ages is observed by scanning electron microscopy,besides that,the cost of phosphogypsum-slag composite cementitious materials is calculated.The study results show that the early strength of phosphogypsum-slag composite cementitious material is lower than that of later strength;the optimum ratio of phosphogypsum-slag composite cementitious material is determined by optimizing the ratio of 7% quicklime,30% phosphogypsum,2%mirabilite and 61% slag powder;SEM showed that ettringite and C—S—H gel are the main hydration products,and with the growth of curing age,the structure became close and the strength increased continuously;and the cost calculation of the optimum ratio of phosphogypsum-slag composite cementitious material is carried out. The cost of cementitious material is180 yuan/t,which is 44% lower than the cost of 38.5 non-standard cement used in Jinchuan Mine.The pipeline transportation characteristics of composite cementitious material filling slurry are measured,and the results can meet the requirements of gravity transportation in Jinchuan Mine.