Characterization of a uranium-rich organic material obtained from a South Texas lignite

Abstract

Results of the density gradient fractionation of a uranium-rich (≈2500 ppm) lignite indicate that the element may be associated with the organic matter in the coal. Dimethyl sulphoxide (DMSO) extracts 40–50% of the uranium from the lignite. Addition of several solvents such as benzene, water and acetone to the DMSO extract yields precipitates which are highly enriched with uranium. Elemental and functional group analyses and infrared absorption chracteristics of the precipitates indicate that they closely resemble coal humic acids. A wavelength-dispersive X-ray dot map of the benzene-derived precipitate shows a homogeneous distribution of uranium. Mass spectrometric information shows that the most abundant species in the precipitates have molecular weights <1500.