煤矿开采过程中,煤矸石的大量堆积及其对地下水的污染影响,已成为亟需解决的生态环境和资源化利用问题。目的目的将煤矸石充填采空区作为矿井水净化的储水空间,既能实现煤矸石资源化利用,又有助于去除矿井水中的氟化物,是一种经济且环保的可行方案。方法方法本研究以矿井水中F−为研究对象,以保德矿采空区煤矸石为充填介质,根据研究区水文地质条件,在25℃、达西流速6.24,3.12,1.56cm/h下开展室内柱模拟实验。利用CDE模型和双点位模型对实验数据进行数值模拟,探讨不同流速下F−运移特征。结果结果结果表明:Cl−作为非反应性示踪剂,其穿透时间与流速负相关,CDE模型可以较好表征其运移规律,弥散作用随着达西流速增加而增大;相较于CDE模型,双点位模型能更好地表征F−运移过程,充填矸石对F−吸附阻滞现象显著,且阻滞系数R和吸附量均随流速减小而增大。F−在煤矸石上的平衡吸附点位占总吸附点位的比值(f值)和分配系数β值随流速减小而增加,而一级动力学吸附速率常数α随流速减小而降低,这表明溶质运移过程中平衡吸附作用随着流速减小逐渐增强。此外,随着淋滤液持续注入,矸石表面的OH−不断被注入的F−通过离子交换吸附作用置换到淋出液中,导致淋出液pH升高,且流速越低,pH升高越明显。结论结论研究结果为高氟矿井水净化提供了一定的理论依据,有助于提升煤矸石资源化利用途径,具有显著的环境经济效益和推广应用潜力。

During coal mining, the massive accumulation of coal gangue and its pollution effects on ground⁃water have become pressing issues in ecological environment management and resource utilization. Objec⁃tives Using coal gangue to backfill goafs as a storage space for purified mine water can not only achieve re⁃source utilization of coal gangue but also help remove fluoride from mine water. This provides an economi⁃cal and environmentally friendly solution. Methods This study focuses on fluoride in mine water, using coal gangue from the Baode mine goaf as the backfill medium. Based on the hydrogeological conditions of the study area, column simulation experiments were performed at 25 ° C with Darcy flow velocities of 6.24, 3.12, and 1.56 cm/h. Experimental data were numerically simulated using the Convection-Dispersion Equa⁃tion (CDE) model and the Two-Site Model to explore the transport behavior of fluoride under different flow velocities. Results The experimental results showed that chloride acted as a non-reactive tracer, and their breakthrough time was negatively correlated with flow velocity. The CDE model effectively described their migration behavior, and dispersion increased with the rise in Darcy flow velocity. For F migration, the Two-Site Model provided a better representation of the migration process compared to the CDE model. Coal gangue demonstrated significant adsorption-retardation effects on fluoride, with the retardation factor R and adsorption capacity increasing as the flow velocity decreased. The equilibrium adsorption site fraction (f value) and distribution coefficient (β value) of fluoride on coal gangue also increased with decreasing flow velocity, while the first-order kinetic adsorption rate constant (α) decreased. This indicates that equilib⁃rium adsorption becomes more dominant as the flow velocity decreases during solute migration. Addition⁃ally, as leachate was continuously injected, OH on the surface of the coal gangue were gradually replaced by F through ion exchange adsorption, leading to an increase in the pH of the effluent. This pH increase was more pronounced at lower flow velocities. Conclusions The results could not only provide a theoretical basis for the purification of high-fluoride mine water but also alleviate the environmental pressure caused by coal gangue accumulation, offering significant environmental and economic benefits with promising poten⁃tial for broader application.