Fingerprinting of a thin secondary mineral film on DU

Discs of depleted uranium (DU), obtained from a British pristine military tank shell were used in our experiments. One sample was placed in a solution containing 2.5 • 10−3 M Ca(NO3)2 and 1.05 • 10−3 M (NH4)3PO4. After a contact time of 360 days the sample was taken out of the solution. IR- and TRLFS measurements were made on the surface of the sample. The spectra obtained were compared with those of natural uranium minerals, formed under oxidising weathering conditions. Comparison of the IR-spectra from the DU surface with those of the reference minerals revealed that the newly formed secondary mineral on DU is a uranium (VI) phosphate. Further identification of the respective uranium phosphate mineral was not possible with IR. However, a comparison between the TRLFS spectra of the newly formed unknown uranium phase on the DU disc with well-known TRLFS spectra of uranium reference compounds clearly showed the presence of meta-autunite.