Determination of Niobium and Tantalum in Raw Niobium-Tantalum Ore and Evaluation of Uncertainty by X-ray Fluorescence
An analytical method for the determination of niobium and tantalum in raw niobium-tantalum ore by X-ray fluorescence fusing was established.The fused glass disc was prepared with low dilution ratio(Li2B4O7:LiNO3:sample=4:0.6:1),and the standard sample for calibration curve was prepared with the mixture of spectrally pure SiO2,Al2O3 and Fe2O3 as matrix,and the standard solution of Nb,Ta and a small amount of interfering elements Rb,Y,Mo,Zr,W and Ce were added to prepare the standard sample for calibration curve.The influence of matrix effect on Nb element was corrected by using Rh target compton scattering line as internal marker.Ta element used HfO2 and Hf Lβ3 as the internal marking line.The spectral interference between Br,Rb,Y,Mo,Zr,Nb,W,Hf and Ta elements in complex raw niobium-tantalum ore and the reagent in this experiment is discussed.For the overlapping interference between Br,Rb,Y,Nb and Hf and Ta,the interference coefficient method is used to deduct step by step.The influence of Mo Kα and Zr Kα background on Nb Kα and the influence of W Lα background on Ta Lα were avoided by selecting 40.000° and 70.500° common background points,respectively.Finally,the net spectral line intensity of analysis elements Nb Kα and Ta Lα was obtained.The standard material GBW07155 of raw niobium-tantalum ore was used as the method to verify the sample,and the uncertainty of the measurement results of Nb and Ta was evaluated.Finally,the results of this method are as follows:w(Nb2O5)=(0.044±0.002)%(k=2);w(Ta2O5)=(0.069±0.002)%(k=2).
X-ray fluorescenceniobiumtantalumspectral line overlap correctionuncertainty
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