Capabilities of micro-Raman spectrometry for the identification of uranium ore concentrates from analysis of single particles
Résumé
It has been proven, by the analysis of macroscopic amount of materiel pressed into pellets, thatRaman spectrometry is a well suited technique to determine precisely the chemical compositions ofuranium ore concentrates (UOCs), which is useful information for nuclear forensics and safeguards.However, as in some cases, only low amounts of UOC are available or the sample is a mixture ofdifferent UOCs, there is a need to carry out the identification at the individual grain or particle’s level.To evaluate the capability of micro-Raman spectrometry (MRS) for this purpose, 15-30 particles withtypical sizes of a few micrometers from five UOCs of known bulk chemical compositions (uranylperoxide – UP, sodium di-uranate – SDU, ammonium di-uranate – ADU, tri-uranium octo-oxide –TUO, and uranyl hydroxide – UH), production process and origins, were analyzed. Spectra were alsocompared with the ones obtained with macroscopic amounts of material pressed into pellets. Resultsshow that for some UOCs (SDU, ADU, UH), micro-Raman spectra are reproducible from one particleto another and in good agreement on one side with available bibliographic data and on the otherside with Raman spectra performed on macroscopic amounts of UOC. However, spectra of particlesfrom the UP and TUO UOCs show that these compounds are mixtures of three species which were identified. In these cases, an acceptable agreement is obtained between the average Ramanspectrum on compressed pellets and the one of most abundant species in analyzed particles.Consequently, an UOC compound or components of a mixture of UOCs can be reliably identified bythe analyses of a limited number of isolated particles of a few µm in size by means of MRS.
Domaines
Chimie
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