A non-polluting method for rapidly purifying uranium-containing wastewater and efficiently recovering uranium through electrochemical mineralization and oxidative roasting

Iron-based materials have been widely used for treating uranium-containing wastewater. However, the iron-uranium solids originating by treating radioactive water through pollutant transfer methods has become a new uncontrolled source of persistent radioactive pollution. The safe disposal of such hazardous waste is not yet well-resolved. The electrochemical mineralization method was developed to rapidly purify uranium-containing wastewater through lattice doping in magnetite and recover uranium without generating any pollutants. An unexpected isolation of U3O8 from uranium-doped magnetite was discovered through in-situ XRD with a temperature variation from 300 °C to 700 °C. Through HRTEM and DFT calculation, it was confirmed that the destruction of the inverse spinel crystal structure during the gradual transformation of magnetite into γ-Fe2O3 and α-Fe2O3 promoted the migration, aggregation, and isolation of uranium atoms. Uniquely generated U3O8 and Fe2O3 were easily separated and over 80% uranium and 99.5% iron could be recovered. These results demonstrate a new strategy for uranium utilization and the environmentally friendly treatment of uranium-containing wastewater.