Determination of Rare-Earth and Accompanying Elements in Niobium−Rare-Earth Ores by Inductively Coupled Plasma Atomic Emission Spectrometry Using Model Calibration and a Mathematical Approach for Resolving Spectral Interferences
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A procedure is developed for the direct determination of all rare-earth and a number of accompanying elements in niobium−rare-earth ores by inductively coupled plasma atomic emission spectrometry after sample decomposition by fusion and further disolution. Because of the complex elemental composition of the samples, numerous mutual overlapping of spectral lines of matrix and rare-earth elements were observed, which required corrections in the calculations of concentrations. The procedure is based on a calibration, modeling spectral and matrix interferences; compilation of the set (mathematical matrix) of mutual interference coefficients; and use of the matrix obtained and the results of sample measurement for the computation of element concentrations. A precise method is used to solve a system of linear equations; it implies the resolution of interferences for all lines. Software utilizing a regularization algorithm ensuring stable solutions of the system of linear equations and also a method of evaluation of the uncertainty of the results of measurements are developed. The method ensures correct results and is rather stable to changes in the composition of the analyzed sample. This was confirmed by the results of analyses of certified reference materials (CRMs) of the composition of rare-earth ores of different origin.
Keywords:rare-earth elements niobium–rare-earth ore inductively coupled plasma atomic emission spectrometry spectral interferences mathematical resolution of spectral interferences
The authors are grateful to A.G. Prudkovsky for the development of the Lin_System software.
The development of the software for processing the results of measurements was done within the framework of a grant of the Russian Foundation for Basic Research no. 16-03-01079.
- 15.NIST Standard Reference Database 78. www.nist.gov/pml/atomic-spectra-database. Accessed June 28, 2018.Google Scholar
- 16.Harrison, G.R., MIT Wavelength Tables, Cambridge: M.I.T. Press, 1969, 2nd ed., vol. 1.Google Scholar
- 17.Harrison, G.R., MIT Wavelength Tables, New York: Wiley, 1939.Google Scholar
- 18.Huang, B., Wang, X., Yang, P., Ying, H., Gu, S., Zhang, Z., Zhuang, Z., Sun, Z., and Li, B., An Atlas of High Resolution Spectra of Rare Earth Elements for ICP–AES, Cambridge: R. Soc. Chem., 2000.Google Scholar
- 19.Bykhovskii, L.Z. and Potanin, S.D., Geologo-promyshlennye tipy redkometal’nykh mestorozhdenii. Mineral’noe syr’e (Geological and Industrial Types of Rare-Metal Deposits: Mineral Raw Materials), Ser. Geol.-Ekonom., no. 28. Moscow: Vseross. Inst. Mineral. Syr’ya, 2009, p. 157.Google Scholar
- 20.http://vims-geo.ru/struktura/struktura-fgbu-vims/analiticheskij-sertifikatsionny-j-ispy-tatel-ny-j-tsentr-asits/otdel-metrologii-standartizatsii-i-akkreditatsii-2/otraslevoj-reestr-standartny-h-obraztsov-sostava/. Accessed June 28, 2018.Google Scholar
- 21.Ore Research and Exploration. www.ore.com.au/ search.php?tag=16. Accessed June 28, 2018.Google Scholar
- 22.Zybinsky, A.M., Simakov, V.A., Kordyukov, S.V., and Karandashev, V.K., Procedure of the Research Board on Analytical Methods 544-AES: Determination of the Mass Fraction of Niobium, Lanthanum, Cerium, Praseodymium, Neodymium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, Yttrium, Scandium, Strontium, Barium, Phosphorus, Titanium, Vanadium, Manganese, and Iron in Rare-Metal and Rare-Earth Ores by Inductively Coupled Plasma–Atomic Emission Spectroscopy, Moscow: Vseross. Inst. Mineral. Syr’ya, 2016.Google Scholar