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    熔融制样-单波长激发能量色散X射线荧光光谱法测定铁矿石中主、次量成分

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

    • 摘要: 将经1 000℃灼烧恒重后的样品0.600 0 g、四硼酸锂-偏硼酸锂混合熔剂6.000 0 g和碘化铵0.500 0 g置于铂-金坩埚中,混匀后在1 150℃的自动熔融炉中熔融30 min,待冷却后取出脱模,制备成玻璃样片,采用单波长激发能量色散X射线荧光光谱法测定其中主、次量成分,能有效解决能谱对轻元素的激发效率低和样品散射的连续谱背景过高问题,从而实现对微量轻元素的测定。以理论α影响系数法对基体效应进行校正,建立了各成分的工作曲线。利用铁矿石标准物质或有证化学分析标准样品中低含量成分的3.14倍标准偏差(s)计算检出限(3.14s),SiO2、Al2O3、P、CaO、MgO、Mn的检出限依次为0.022%,0.024%,0.005 0%,0.004 4%,0.006 2%和0.006 5%。对不同铁矿石样品测定12次,高于检出限的成分测定值的相对标准偏差均小于8.0%。采用不同方法进行比对试验,除质量分数在0.10%以下的MgO之外,本方法测定其他成分所得结果与对比方法的测定结果吻合。

       

      Abstract: 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.

       

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