Transformation of Uranium Forms During Percolation of a Uranium Tailing Leachate Through Clay Layer
There is residual uranium in uranium tailings,which will dissolve out under the action of water flow,and migrate in the unsaturated zone and groundwater with the flow of leachate.The occurrence form of uranium in the leachate will affect the migration of urani-um.In this study,the leaching of uranium tailings and the transfer of leachate in clay were investigated by column experiments,and the occurrence forms of uranium were simu-lated using the PHREEQC software.The experimental results show that the concentration of uranium leached from the tailings by the leachate is very low,and the clay layer at the bottom of the tailings does not have a high adsorption efficiency for the low concentration of uranium;moreover,the tailings leachate is acidic,and the H+and SO2-4 in the tailings eas-ily migrate with the leachate,and the clay does not have a strong capacity to adsorb them.There are four main forms of uranium in the tailings leachate and clay penetrating fluid and the relative order of content is UO2 F+>UO2 SO4>UO2+2>UO2(SO4)2-2.The forms of ura-nium do not change significantly during the migration process through the clay layer and F-and SO2-4 are the main controlling factors affecting the migration of uranium in the dissolved state.The research can provide a theoretical basis for uranium tailings groundwater reme-diation and uranium soil pollution remediation.
uranium tailingsleachateoccurrence forms of the uraniumclay
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