Determination of Primary and Secondary Components in Iron Ore by Single Wavelength Excitation Energy Dispersion X-Ray Fluorescence Spectrometry with Melt Sample Preparation

The sample burned at 1 000℃ to constant mass (0.600 0 g), 6.000 0 g of the mixed flux of lithium tetraborate and lithium metaborate, and 0.500 0 g of ammonium iodide were added into a platinum-gold crucible. After mixing, the mixture was melt in an automatic melting furnace at 1 150℃ for 30 min. After cooling, the mold was taken out and the glass sample was got, in which primary and secondary components were determined by single wavelength excitation energy dispersion X-ray fluorescence spectrometry. The above method could effectively solve the problems of low excitation efficiency of energy spectrum for light elements and high continuous spectral background of sample scattering, so as to achieve determination of trace light elements. The matrix effect was corrected by the influence coefficient method of theory α, and the working curves of components were established. 3.14 times of standard deviation (s) of the components with low content in the iron ore reference materials or certified chemical analysis standard samples was used to calculate the detection limits, with detection limits (3.14s) of 0.022% for SiO₂, 0.024% for Al₂O₃, 0.005 0% for P, 0.004 4% for CaO, 0.006 2% for MgO, and 0.006 5% for Mn, respectively. Different iron ore samples were determined 12 times, and RSDs of the determined values of components above the detection limits were less than 8.0%. Different methods were used for comparison tests. Except for MgO with mass fraction less than 0.10%, the results of this method were consistent with those of the comparison methods.