Zhang Yan, Yang Xiaoyun, Tighe Susan
College of Energy and Transportation Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.
Department of Civil & Environmental Engineering, University of Waterloo, Waterloo, N2L 3G1, Canada.
Materials (Basel). 2019 Sep 30;12(19):3207. doi: 10.3390/ma12193207.
Coal gangue, a solid waste produced in coal production, had caused serious environmental pollution due to accumulation on dumps. Embankment filling can solve the problem while significantly consuming the amount of coal waste for mining. The main purpose of this study is to investigate the mechanical properties and microscopic structure of coal gangue when it is subjected to erosion from water environment with different acidity. Using immersion testing to evaluate its stability in different hydro-chemical environments. Mechanical property parameters of coal gangue treated by solutions were investigated. The action microstructure of coal gangue was revealed through a series of X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). The results show that acidic solution behaved better improvement effect on compressive modulus and fraction of coal gangue samples owing to the generation of quartz and the reduction of aluminum, dissolving of some substances, and transforming of small scattered angular grains through soaking treatment. Alkalinity treatment can be chosen to improve cohesion of coal gangue as a result of polymeric silicon aluminum salt, with high viscosity, was produced by chemical reaction during immersion. Therefore, aqueous solution treatment contributes to engineering properties and presents great potential in both supplement road building materials and recycling of coal gangue.
煤矸石是煤炭生产过程中产生的固体废弃物，由于其在矸石堆上的堆积，已造成严重的环境污染。筑堤填埋可以解决这个问题，同时大量消耗采矿产生的煤矸石。本研究的主要目的是研究煤矸石在不同酸度的水环境侵蚀下的力学性能和微观结构。采用浸泡试验来评估其在不同水化学环境中的稳定性。研究了经溶液处理的煤矸石的力学性能参数。通过一系列X射线衍射（XRD）、X射线荧光光谱（XRF）、扫描电子显微镜（SEM）和能谱分析（EDS）揭示了煤矸石的作用微观结构。结果表明，酸性溶液由于石英的生成、铝的减少、一些物质的溶解以及浸泡处理后小的分散角状颗粒的转变，对煤矸石样品的压缩模量和级配表现出更好的改善效果。由于浸泡过程中化学反应产生了高粘度的聚合硅铝盐，因此可以选择碱处理来提高煤矸石的内聚力。因此，水溶液处理有助于改善工程性质，在补充道路建筑材料和煤矸石回收利用方面都具有巨大潜力。
