Uranyl peroxide ((UO2)(O2)·4H2O; UO4) precipitation for uranium sequestering: formation and physicochemical characterization

Applicability of uranium peroxide ((UO2)(O2)·4H2O; UO4) precipitation to remove uranium from secondary wastewaters, generated as part of a spent uranium catalyst treatment process, has been studied. Precipitation characteristics of UO4 were evaluated as a function of pH, stirring status, time, and initial uranium concentrations. Optimized conditions were applied to the real uranium wastewater achieving ≥ 99% removal efficiency within 24 h. Dissolved impurities (Si, Sb, Fe) were co-precipitated with UO4 leading to increased particle sizes and faster precipitation kinetics. Uranium was separated effectively from the wastewater to below the 1 mg L−1 criteria necessary for secondary wastewater discharge.