Comparison of sample preparation techniques and matrix effects correction methods for X-ray fluorescence determination of total iron and rock-forming elements in iron ores

The genesis of deposits determines wide variations in the mineral and chemical composition of iron ores. It is necessary to determine the content of not only the main ore element (Fe), but also the main rock-forming elements, especially those that affect the quality of the product obtained from the ore (for example, P and Mn). When determining Fe, Mg, Al, Si, P, Ca, Ti, and Mn in iron ores by wavelength-dispersive X-ray fluorescence analysis, two common sample preparation techniques were compared: pressing powder samples on a boric acid substrate and homogenization of calcined sample by fusion with lithium tetraborate. For each method, the repeatability of the measurement of analytical lines was evaluated, calibration equations were constructed using certified reference materials of iron ores of various types and two methods for matrix effects correction (fundamental parameters and empirical intensities) were compared. Iron ores samples from the Korshunovskoye, Rudnogorskoye and Tatyaninskoye deposits of the Angarsk ore province (north of the Irkutsk region and southeast of the Krasnoyarsk Krai) were analyzed by the certified atomic absorption and spectrophotometric techniques, and the results were compared with those obtained by X-ray fluorescence analysis. For the main ore element (Fe) and some rock-forming elements (Mg, Al, Si, P) determination, the fusion technique provided a smaller error, however, both techniques could be used to determine Ca, Ti, and Mn. The choice of the sample preparation technique for wavelength-dispersive X-ray fluorescence analysis of iron ores should be based on the appropriateness of the financial and labor costs and the necessary accuracy of the analysis. Keywords : wavelength-dispersive X-ray fluorescence analysis, iron ores, rock-forming elements, borate glasses, matrix effects correction DOI: http://dx.doi.org/10.15826/analitika.2020.24.2.005 Victor M. Chubarov 1 , Elena I. Borkhonova 2 , Alena A. Amosova 1 1 Vinogradov Institute of Geochemistry, SB RAS, 1 А Favorsky st., Irkutsk 664033, Russian Federation 2 Irkutsk State University, 1 Karl Marx st., Irkutsk 664003, Russian Federation