尾矿库淋滤液中氟垂向迁移的土柱淋滤试验

Column leaching tests for modeling vertical migration of fluorine contamination in tailings pond

淋滤液引起地下水系统污染问题日益突出.本文针对承钢双大尾矿库淋滤液引起地下水氟污染问题展开研究,通过现场勘探、取样,以及尾矿砂矿物成分和粘粒含量分析,在此基础上进行室内土柱淋滤试验以模拟氟在尾矿砂中的迁移过程,研究其迁移行为特征和影响因素.研究结果表明,由于尾矿砂矿物成分中铁绿泥石和正长石等粘土矿物居多,是氟的良好吸附剂,因此该过程主要受解吸-吸附作用控制.具体表现为在上部尾矿砂中解吸作用占优和下部尾矿砂中吸附作用占优,致使氟含量随深度增加有增大的趋势,这与钻孔岩芯段中氟含量随深度变化曲线相符,也与尾矿砂粘粒含量随深度增加的特点相一致,说明氟迁移过程的主要影响因素是尾矿砂的矿物成分和粘粒含量.了解这一过程为后期地下水氟污染治理提供参考.

The pollution problem of groundwater caused by taillings leachate is increasingly outstanding.The study of this paper is focused on an issue of fluorine contamination of groundwater caused by tailings leachate,in Shangda taillings pond,Chengde iron and steel group.Based upon site exploration,sampling and analysis of mineral composition and clay content,laboratory column leaching tests have been done to model the process of vertical migration of F,in order to reveal its characteristics and influencing factors.The results show that the process is mainly controlled by the desorption-adsorption equilibrium,due to the high content of clay minerals in tailings sand,like chlorite and orthoclase,which are good adsorbents.It is desorption that dominates in the upper tailings sand and adsorption in the lower,which causes the fluorine content of tailings sand increased with the depth.The results agree with the vertical distribution curve of Fluorine in tailings sand of boreholes,as well as the behavior that the clay content increased by the depth.It concludes that the main influencing factors of the desorption-adsorption equilibrium are the mineral composition and clay content of tailings sand.It can provide reference for the fluoride pollution control in groundwater to know this process.