蒙陕接壤区煤矿采空区水-岩系统中氟来源及释放规律

采空区是高氟矿井水形成的关键区域，其水-岩系统中氟的来源与溶解释放决定了矿井水中氟的富集或贫化。针对蒙陕接壤区3-1煤采空区矿井水氟来源及释放规律不清晰问题，采用水化学测试、岩石矿物成分分析、矿物扫描电镜与能谱检测，以及室内水-岩作用仿真模拟试验，查明矿井水氟物质来源与赋存载体，揭示岩石中氟释放规律。结果表明：研究区3-1煤矿井水水化学类型主要为HCO₃-Na与SO4-Na型，3-1煤采空区矿井水氟浓度高于3-1煤生产工作面的矿井水浓度，且采空区矿井水pH、Na⁺/Ca²⁺浓度比均大于工作面矿井水。3-1煤采空区矿井水F-的物质来源为泥岩与粉砂岩，2种岩石中氟平均含量分别为741、610 mg/kg，氟在固相中的主要赋存载体为蒙脱石、高岭石、伊利石及绿泥石。采空区水-岩系统中氟的释放受岩性、粒径、pH、温度及Na⁺/Ca²⁺浓度比5个因素影响。其中，泥岩及粉砂岩中的氟比细砂岩中的更容易释放进入水中；无论何种岩性，随着粒径的减小，氟释放F-的浓度增大；此外，碱性、高温及高钠低钙的...

Source and release law of fluorine in water-rock system of coal mine goaf in contiguous area of Shaanxi and Inner Mongolia

The coal mine goaf is the key area for the formation of high-fluoride mine water, and the source and release of fluorine in goaf water-rock system determines the enrichment or depletion of fluorine in mine water. Aiming at the unclear source and release rule of fluorine in the mine water of 3-1 coal goaf in the contiguous area of Shaaxi and Inner Mongolia, hydrochemical test, mineral composition analysis, mineral scanning electron microscopy and energy spectrum detection, as well as laboratory water-rock simulation experiment, were conducted to determine the source and occurrence carrier of fluorine in coal mine water, and to reveal the release rule of fluorine in the rock. The results show that the main hydrochemical types of mine water in 3-1 coal goaf of the study area are HCO₃-Na and SO₄-Na. The concentration of fluorine in mine water of 3-1 coal goaf is higher than that in the newly born mine water of 3-1 working face. Besides, the pH and Na+/Ca2+ ion ratio of mine water in the coal goaf are higher than that in the working face. Therefore, the fluoride in mine water in 3-1 coal goaf mainly comes from mudstone and siltstone, with the average fluorine content of 741 mg/kg and 610 mg/kg, respectively. The main carriers of fluorine in solid phase are smudge, kaolinite, illite and chlorite. Above all, the release of fluorine in the water-rock system of the goaf is controlled by lithology, particle size, pH, temperature and Na+/Ca2+ concentration. Specifically, fluorine in mudstone and siltstone is more easily released into water than that in the fine sandstone. Regardless of lithology, the concentration of fluorine ions released increases with the decrease of rock particle size. Moreover, the hydrochemical environment characterized by alkaline, high temperature, high sodium and low calcium can promote the dissolution and release of fluorine from rocks to water.