Efficiency of Electrochemical Filter in Treating Uranium Tailings Leachate

Abstract

In this work, a novel graphite-based electrochemical filter was developed for the efficient and environmentally friendly treatment of uranium tailings leachate. The filter utilizes graphite particles as filler and carbon felt as a conductor, powered by a DC power supply and driven by a peristaltic pump. In a non-circulating continuous operation filter experiment, uranium tailings leachate was tested for uranium removal efficiency under different operating parameters such as voltage and residence time, using both synthetic wastewater and actual uranium mine wastewater. This study is based on the fundamental principles of metal electrochemical reduction. The efficacy of this device for the continuous flow treatment of uranium tailings leachate was systematically investigated. The mechanism of uranium tailings leachate treatment by the electrochemical filter was elucidated through electrochemical analysis and product characterization. The results highlight that voltage and hydraulic retention time are critical factors influencing the efficiency of electrochemical filter treatment. Specifically, 4.0 V and 10 hours were identified as the optimized voltage and suitable hydraulic residence time, respectively, for the treatment of uranium tailings leachate using the electrochemical filter, resulting in a uranium removal rate exceeding 97%. In actual uranium tailings leachate applications, the maximum extraction rate can reach 5275 μmol/(m3∙h), confirming the feasibility of electrochemical filter in removing uranium from actual uranium tailings leachate and its good selectivity in complex water quality applications, the device can be quickly applied to uranium tailings leachate collection facilities and achieve in-situ uranium extraction. The voltage increase can significantly enhance the uranium extraction performance and can be portablely deployed in uranium mine water. In-situ uranium processing and recovery is achieved in processing and collection facilities. Characterization techniques such as field emission scanning electron microscope-energy spectrum analyzer(FESEM-EDS) and X-ray photoelectron spectrometer(XPS) were employed to analyze the reaction products on the graphite particles, revealing that uranium was evenly distributed on the surface of graphite particles and exhibits a stable crystal structure, the main mechanism responsible for uranium removal was adsorption-reduction, with uranium recovery products deposited on the electrode surface in the form of a mixture of U(Ⅳ) and U(Ⅵ). A cost estimation shows that the operational cost of extracting uranium from uranium tailings leachate using this device falls within the range of 176.6 ￥/kgU to 587.5 ￥/kgU. This cost is significantly lower than that of conventional land-based uranium resource development, making it economically viable. This research provides both theoretical and technical support for the efficient and environmentally friendly treatment of uranium tailings leachate.

Keywords

• electrochemical filter
• uranium tailings leachate
• adsorption-reduction
• uranium removal efficiency