Uranium metal corrosion in soils with different soil moisture regimes

Abstract

Depleted uranium (DU) munitions have a potential impact on the environment. However, the characterization and horizontal migration of DU corrosion products over a continuous period time in different soil moisture regimes were not well studied. X-ray Power Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier-transform Infrared Spectroscopy (FT-IR), Raman spectra and Inductively Coupled Plasma Mass Spectrometry (ICP-MS)/X-ray Fluorescence spectroscopy (XRF) were used to characterize the corrosion products, the rates of formation of uranium oxides and the distribution of uranium in soil. UO2.8 and UO3 appeared in the DU metallic fragment/soil systems under the saturated soil regime in 4 weeks. UO3 was observed in the soil with the field capacity moisture regime in 16 weeks, but not in the air dry soil. Corrosion started at angled cracks, small pits and edges. DU metal corrosion rates decreased following the trend: Saturated soil > Field capacity soil > Air dry soil. Under the sequential extraction of the soil fractions, the percentage of uranium bound to the carbonate fraction was more than 41.5 %. This study demonstrates that soil moisture content plays a role in DU metal corrosion and migration.