铀尾矿中铀在模拟降雨淋滤条件下的释放规律及机理研究

Study on the release law and mechanism of U from uranium mill tailings under simulated rainfall

为查明某铀尾矿中U在模拟降雨淋滤过程中的释放规律和机理,采用半动态淋滤的方法对铀尾矿的溶浸特征进行研究,并通过扫描电子显微镜和X射线衍射仪对铀尾矿淋滤前后的样品进行对比分析。结果表明,在半动态淋滤过程中,U的释放速率随淋滤时间增长而减小,随淋滤液pH值的增加U累计释放量逐步减少,但pH值差异对U累计释放量影响并不显著,U的释放是来自矿物表面吸附的铀酰-硫酸等配合物以及二水石膏形成过程中吸附的含铀配合物的溶解。

To investigate the release law and mechanism of uranium form the uranium tailings under simulated rainfall,the method of semi-dynamic leaching of uranium tailings was adopted to investigate the leaching characteristics and uranium tailings leaching residue was analyzed by SEM and XRD.The results of semi-dynamic leaching process showed that the release rate of uranium decreases with increasing leaching time.With the pH of leachate increase,the cumulative release amount of uranium gradually decrease,but the different of pH influence on uranium cumulative release amount is not significant,the release of uranium is from the mineral surface adsorption of uranyl sulfate complex dissolved in the process of the formation of dihydrate gypsum and adsorption of uranium complex released by leaching solution.