闭坑瓦斯矿井残余CO2-矿井水-岩作用实验模拟

Experimental Simulation of Residual CO2-Mine Water-Rock Interaction in Closed Gassy Coal Mines

基于三相反应模拟系统,以CO2为主要残余瓦斯气体,以煤中典型矿物和高硫酸盐高铁矿井水为固、液反应相,开展闭坑瓦斯矿井水-岩-气反应模拟实验,对比分析了三相反应模拟实验中矿井水化学成分变化和矿物组分的变化。结果表明:在水-岩-气三相模拟反应中,矿井水的pH升高,Eh降低,矿物相的溶解导致矿井水中Ca^2+、HCO3^-、SO4^2-以及可溶性SiO2的含量出现不同程度的增加,Mg^2+含量无明显变化,总Fe浓度下降,矿化度明显增加;煤岩典型矿物均出现了不同程度的溶解反应,方解石发生溶解作用时,反应过程中会生成新的碳酸盐矿物,黄铁矿在溶解的同时伴随着绿泥石的生成。

Based on the three-phase reaction experiments,taking CO2 as the main gas phase,the typical minerals in coal as solid phase and mine water rich in iron and sulfate as liquid phase,the water-rock-gas reaction simulation experiment of closed gassy mine is carried out.The changes of chemical composition of mine water and coal mineral composition are compared and analyzed.The results have showed that in the mine water-rock-gas reaction,the pH value of the mine water increases and the Eh decreases,and the dissolution of mineral phase resulted in the increase of the content of Ca^2+,HCO3^-,SO4^2- and soluble SiO2 in mine water,while the content of Mg^2+ did not change significantly,the total Fe concentration decreased,and the salinity increased significantly.Typical minerals of coal and rock have different degrees of dissolution reactions.When calcite dissolves,new carbonate minerals will be generated in the reaction process,while pyrite dissolves with the generation of chlorite.