• 中文核心期刊
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X射线荧光光谱在地质分析中的若干难点及应用现状

Some Difficulties and Status in the Application of X-ray Fluorescence Spectrometry in Geological Analysis

  • 摘要: X射线荧光光谱法(XRF)具有无损、快速、环保和分析精度高等特点,常作为地质样品中主量和微量元素分析的首选方法。然而,由于地质样品的矿物组成、物理结构特征(如尺寸、形状和分层等)和化学成分(如元素组成、化学形态等)的复杂性与多样性,XRF在地质样品分析的实际应用中存在一些技术难点。本文从小样品量和珍贵样品的分析、XRF的散射效应的应用、易挥发元素分析、变价元素分析和稀有金属分析等方面,对XRF在地质分析中的难点进行了总结与评述。指出制备易于保存和便于反复测量的小尺寸样片是小样品量和珍贵样品XRF分析的合适方法;XRF散射效应可用于成分未知的样品中更多化学成分信息的获取以及异质性样品原位分析误差的校正;超细粉末制样、稳定剂的加入和标准加入法建立工作曲线是解决易挥发元素XRF分析困难的方法。认为元素的特征X射线相对强度可用于变价元素价态和形态的分析;优化校准曲线、降低熔融制样的稀释比、高压激发和改善谱线重叠干扰是解决稀有金属分析困难的有效途径。

     

    Abstract: X-Ray fluorescence spectroscopy (XRF) has become one of the widely used methods for main and trace elements analysis in geological samples because of its characteristics of non-destructive, fast, environmental friendly and high analytical precision. However, there are still some difficulties in practical analysis of geological samples with XRF due to the complexity and diversity of mineral composition, physical structural characteristics (e.g., size, shape, delamination and inclusions) and chemical composition of geological samples. This paper reviews analysis difficulties in geological samples with XRF from five aspects including small size samples and precious samples analysis, the application of scattering effect, the analysis of volatile elements, variable valence elements and rare metals. It is indicated that the preparation of small beads or pellets which are easy to save and facilitate repeated measurement is a suitable method for small sample size and precious samples. The XRF scattering effect can be used to obtain more chemical information in the samples with unknown composition and to correct the error of analysis in situ of heterogeneous samples. Preparation of ultrafine powder pellet, addition of stabilizer and standard addition method establishing work curve are solutions of volatile element analysis .Relative intensity of characteristic X-ray fluorescence can be used for analysis of valence state and morphology of variable valence elements. Optimization of the calibration curve, preparation of low-dilution (sample to flux ratios) glass beads, excitation at high X-tube voltage and correction of spectral line overlap interference are effective ways for rare metals analysis. The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202403150052.

     

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