Interference free fluorimetric determination of uranium in Indian monazites

A simple interference free extractive pellet fluorimetric method of determining uranium in monazite mineral samples has been developed. The quenching of fluorescence of uranium by thorium and the extent of quenching was studied. Pellet fluorimetric method of uranium determination was carried out using solvent extraction separation of uranium to ethyl acetate in the presence of sodium salt of ethylene diamine tetra acetic acid (Na-EDTA). The optimum concentration EDTA and the effect of EDTA on uranium fluorescence were studied. The accuracy of the method was established by analyzing a synthetic sample and certified reference materials (IGS-36 and DH-1a). Results were compared with those obtained by other principally different analytical techniques after solvent extraction separation using the standardized procedure. The precision obtained at 0.2% U₃O₈ was better than ± 10%. The modified extraction method of addition of EDTA with salting out agent prevented the co-extraction of thorium and improved the fluorescence intensity of uranium in monazite samples. (author)