铀尾矿渗滤液中铀在地下水中的迁移模拟

选择某铀尾矿库作为研究对象,采集尾矿坝中的铀尾矿样品、含水层砂土样品及隔水层粘土样品,研究U在关键地层土壤样品上的等温吸附规律及降雨条件下U的浸出过程,得到U在关键地层的吸附迁移参数及源项释放规律,并运用FEFLOW6.2软件建立铀尾矿评价区地下水三维模型,模拟U的迁移行为及浓度分布。实验结果表明U在砂土与粘土上的吸附符合线性等温吸附模型,分配系数K_d分别为20.41 L/kg、45.92 L/kg;实验周期内酸雨淋浸与去离子水淋浸条件下U浸出平衡浓度分别为0.83 mg/L、0.79 mg/L,浸出率分别为46.07%、20.92%。模拟结果表明经过30年的迁移,U污染晕峰值浓度为0.595 mg/L,峰值浓度迁移距离为36.44 m;经过50年的迁移,U污染晕峰值浓度为0.440 mg/L,峰值浓度迁移距离为42.93 m。

Simulation of uranium migration in groundwaterfrom uranium tailings leachate

A uranium tailings dam in northern China was selected as the research object to collect uranium tailings samples in tailings dams,aquifer sand samples and water barrier clay samples.The isotherm adsorption law of U on soil samples and the leaching process of U under rainfall conditions were studied to obtain U adsorption and migration parameters in key strata and the release rule of source terms.Using FEFLOW6.2 software to establish a three-dimensional model of groundwater in the uranium tailings evaluation area,simulating U migration behavior and concentration distribution.The results show that the adsorption of U on sand and clay conforms to the linear isothermal adsorption model,the distribution coefficients k_d are 20.41 L/kg and 45.92 L/kg respectively.The equilibrium concentrations of U under acid rain leaching and deionized water leaching conditions during the experiment period were 0.83 mg/L and 0.79 mg/L,respectively.And the leaching rates were 46.07% and 20.92%,respectively.The simulation results show that after 30 years of migration,the maximum concentration of U in groundwater will reach 0.595 mg/L and the peak concentration migration distance is 36.44 m.After 50 years of migration,the maximum concentration of U in groundwater will reach 0.440 mg/L and the peak concentration migration distance is 42.93 m.