A modified method for the determination of uranium in Nb/Ta minerals by LED fluorimetry

A modified LED fluorimetry determination of uranium in Nb/Ta minerals has been developed. The mineral is brought into solution by fusion with mixed phosphate flux (NaH2PO4, H2O and Na2HPO4). Iron quenches uranium fluorescence when it is present above the ratio of (iron to uranium) 100. Uranium is separated in ethyl acetate by solvent extraction and then stripped back into pyrophosphate buffer (pH similar to 7) prior to its LED fluorimetry determination. This modified method has been applied for the determination of uranium in synthetic mixtures and Nb/Ta minerals including Certified Reference Materials (X1807) with high degree of accuracy and precision.