Kinetics of Uranium Extraction from Uranium Tailings by Oxidative Leaching

Extraction of uranium from uranium tailings by oxidative leaching with hydrogen peroxide (H2O2) was studied. The effects of various extraction factors were investigated to optimize the dissolution conditions, as well as to determine the leaching kinetic parameters. The behavior of H2O2 in the leaching process was determined through scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and x-ray diffraction analysis of leaching residues. Results suggest that H2O2 can significantly improve uranium extraction by decomposing the complex gangue structures in uranium tailings and by enhancing the reaction rate between uranium phases and the leaching agent. The extraction kinetics expression was changed from 1 − 3(1 − α)2/3 + 2(1 − α) = K0(H2SO4)−0.14903(S/L)−1.80435(Ro)0.20023e−1670.93/Tt (t ≥ 5) to 1 − 3(1 − α)2/3 + 2(1 − α) = K0(H2SO4)0.01382(S/L)−1.83275(Ro)0.25763e−1654.59/Tt (t ≥ 5) by the addition of H2O2 in the leaching process. The use of H2O2 in uranium leaching may help in extracting uranium more efficiently and rapidly from low-uranium-containing ores or tailings.