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    预氧化-熔融制样-X射线荧光光谱法测定铌铁中主次量元素

    Determination of Major and Minor Elements in Ferroniobium by X-Ray Fluorescence Spectrometry with Pre-Oxidation and Fusion Sample Preparation

    • 摘要: 为简化传统湿法检测铌铁中主次量元素时繁琐的操作步骤以及解决X射线荧光光谱法检测时坩埚腐蚀、基体效应大、铌元素测定准确度差等问题,优化了预氧化、仪器工作条件,采用四硼酸锂、碳酸锂、五氧化二钒预氧化样品,四硼酸锂熔融制备玻璃片,X射线荧光光谱法同时快速测定铌、硅、磷、铝和钛等主次量元素的含量。取2.000 0 g四硼酸锂、1.000 0 g碳酸锂、0.500 0 g五氧化二钒、0.200 0 g样品,混匀后于950℃预氧化30~40 min。冷却至形成固体小球,放入盛有4.000 0 g四硼酸锂的铂黄坩埚中,滴加0.225 g碘化钾溶液(300 g·L-1),于1 050℃预熔融120 s,熔融720 s,静置10 s。冷却直至形成玻璃片,脱模后按照优化的仪器工作条件测定。结果显示:5种元素的质量分数在一定范围内和荧光强度呈线性关系,相关系数均大于0.999 0。标准样品中5种元素测定值的相对标准偏差(n=6)为0.26%~1.5%;方法用于标准样品和自制标准样品的分析,所得测定值与委外测定值进行比较,测定值偏差的绝对值均在系列标准GB/T 3654—2019的允差范围内。

       

      Abstract: To simplify the cumbersome steps in traditional wet method as well as solve the problems of crucible corrosion, large matrix effect, and poor accuracy of niobium element determined by X-ray fluorescence spectrometry for detection of major and minor elements in ferroniobium, the conditions of pre-oxidation and instrument working were optimized. Lithium tetraborate, lithium carbonate, and vanadium pentoxide were used for pre-oxidation, lithium tetraborate was used for preparation of glass sheets by fusion, and X-ray fluorescence spectrometry was used to quickly determine niobium, silicon, phosphorus, aluminum and titanium elements, simultaneously. The 2.000 0 g of lithium tetraborate, 1.000 0 g of lithium carbonate, 0.500 0 g of vanadium pentoxide, and 0.200 0 g of sample were mixed thoroughly, and pre-oxidized at 950 ℃ for 30-40 min. After cooling to form a solid ball, the mixture was placed into a platinum yellow crucible containing 4.000 0 g of lithium tetraborate, and 0.225 g of 300 g·L-1 potassium iodide solution was added dropwise. The above mixture was pre-melted for 120 s, melted for 720 s, and settled for 10 s at 1 050 ℃. Glass sheets were formed and demolded after cooling, and determination was carried out according to the optimized instrument working conditions. It was shown that linear relationships between values of the mass fraction and the fluorescence intensity of the 5 elements were kept in definite ranges, with correlation coefficients greater than 0.999 0. RSDs (n=6) of the determined values of the 5 elements in standard samples were found in the range of 0.26%-1.5%. The proposed method was applied to the analysis of standard samples and self-made standard samples. Compared with the outsourced determined values, the absolute values of biases were within the allowable tolerance range specified by the series standards GB/T 3654—2019.

       

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