【摘要】 高放废物处置库近场地球化学稳定性主要由膨润土和地下水之间的长期化学作用控制。为了查明膨润土与地下水作用演变情况，以PHREEQC为计算平台，从热力学角度分别模拟了不同温度条件下高庙子钠基膨润土在纯净水和北山地下水中的反应进程，计算得出次生矿物、pH值和液相主要阳离子随反应进度的变化情况。结果表明：膨润土在纯净水中依次生成的次生矿物有三水铝石、针铁矿、镁蒙脱石和钙蒙脱石；在北山地下水中依次生成的次生矿物为三水铝石、针铁矿、镁蒙脱石和方解石；溶液的pH值均能维持在碱性范围；温度对次生矿物的种类影响不大，对反应进度有影响。最后以计算结果为基础，得出了不同温度条件下膨润土-北山地下水体系关键矿物的SiO₂浓度-pH值平衡相图。更多还原

【Abstract】 The geochemical stability of near field in high level radioactive waste disposal repository is mainly controlled by long term chemical interaction between bentonite and groundwater.The reaction processes of GMZ Na-bentonite in purified water and Beishan groundwater at different temperatures were calculated respectively from thermodynamic aspects using software PHREEQC in the paper Secondary minerals,pH value and main cation composition were simulated.The results showed that secondary minerals generated in purified water were gibbsite,goethite,Mg-montmorillonite,and Ca-montmorillonite,the secondary minerals generated in Beishan groundwater were gibbsite,goethite,Mg-montmorillonite,and calcite successively,as well as pH value could maintain in the alkaline range.The secondary mineral species were not affected by temperature,but interaction process could be influenced by temperature.The SiO₂concentration-pH equilibrium phase diagrams of key minerals in bentonite-groundwater system at different temperatures were obtained at last.更多还原