高浓度煤矸石胶结充填材料骨料级配优化研究

Study on aggregate grading optimization of high density coal refuse cemented backfill material

骨料占充填料浆体积的2/3左右,是影响胶结充填材料性能的重要因素。综合利用扫描电镜SEM、EDS能谱分析、X荧光光谱分析(XRF)、X射线衍射分析和傅里叶变换红外光谱(FTIR)五种微观分析手段,对煤矸石骨料的微观形貌、元素组成、氧化物含量和矿物组成进行了分析探究。该煤矸石的成分和矿物结构决定了其具有一定的强度,作为胶结充填材料骨料使用能够产生良好的骨架强度。为改善煤矸石胶结充填材料的流动性和可泵送性,对煤矸石破碎骨料的颗粒级配进行了筛分析试验,并利用ORIGIN软件对颗粒级配进行非线性回归分析。借鉴混凝土配合比设计的经典理论,对煤矸石破碎骨料进行了优化设计,优化后的骨料级配递减指数n=0.4093,<0.3 mm的骨料占比为17.67%。试验对比了经优化的骨料和未优化的骨料配制的胶结充填材料的工作性和凝结硬化后的强度,经优化了的骨料配制的胶结充填材料流动性更好(坍落度为260 mm,扩展度为590 mm)、泌水率低(仅为4.3%)、凝结硬化后的强度合适(28 d抗压强度为5.81 MPa),工作性能与未经过优化的胶结充填材料相比性能有了很大的提高。研究配制的高浓度煤矸石胶结充填材料在晋能控股某矿采空区进行了充填施工,充填材料易于泵送,管输顺畅,未发生堵管现象。

The aggregates would take about 2/3 of the backfill slurry volume and would be the important factor effected to the performances of the cemented backfill material.Five micro analysis means including the scanning electron microscope SEM,EDS energy spectrum analysis,X fluorescence spectrum analysis(XRT),X fluorescence spectrum analysis and Fourier transform infrared spectroscopy(FTIR)were comprehensively applied to analyze and study the micromorphology,elemental composition,oxide content and mineral composition of the coal refuse aggregates.The content and mineral structure of the coal refuse decided the coal refuse with a certain strength and as the cemented backfill material,the aggregate applied could have a good skeleton strength.In order to improve the fluidity and pumping of the coal refuse cemented backfill material,a screening analysis test was conducted on the grain gradation of the coal refuse crushed aggregates.The ORIGIN software was applied to the nonlinear regression analysis on the grain gradation.With the references to the classical theory of the concrete mix design,an optimum design was conducted on the coal refuse crushed aggregate.After the optimization,the aggregate gradation decline index n would be 0.4093 and the aggregate<0.3 mm would take 17.67%.The test comparison was conducted on the working performances of the cemented backfill material and the strength after the setting and hardening of the cemented backfill material prepared with the optimized aggregate and unoptimized aggregate.The cemented backfill material prepared with the optimized aggregate would have a better fluidity(the slump being 260 mm and extensibility being 590 mm),a low bleeding rate(only 4.3%),the strength suitable after the setting and hardening(28 days compression strength being 5.81 MPa)and the working performances and the comparison performances of unoptimized cemented backfill material highly improved.The studied and prepared high density coal refuse cemented backill material were applied to the back-fill construction in a mine goaf of Jinneng Holding.The backfill material would be easy to be pumped.The pipeline transportation could be smoothly and there was no jammed phenomenon occurred in the pipeline.