熔融制样-X射线荧光光谱法测定硅质、铝质、镁质和铬质耐火材料中15种组分

硅质、铝质、镁质和铬质耐火材料中MgO、Na₂O、Fe₂O₃、MnO、Cr₂O₃、TiO₂、P₂O₅、SiO₂、CaO、K₂O、Al₂O₃等组分含量的分析,一般采用EDTA滴定法、分光光度法、原子吸收光谱法测定,操作繁琐,耗时长;而使用X射线荧光光谱法分析时,4种基体的耐火材料需要采用不同的熔融方法和校准曲线。为了将4种基体的耐火材料统一制样方法,并使用同一组校准曲线同时测定MgO、ZrO₂、Na₂O、ZnO、NiO、Fe₂O₃、MnO、Cr₂O₃、V₂O₅、TiO₂、P₂O₅、SiO₂、CaO、K₂O、Al₂O₃等主次组分,实验选用3套国外耐火材料标准样品,并对熔融温度、时间、稀释比等熔融制样条件进行优化;通过峰位及强度扫描确定各元素电压、电流、准直器等条件,达到灵敏度与分辨率最佳,通过扫描PHA确定脉冲宽度,提高准确度。理论α系数校正元素间吸收增强效应,用比例法计算校正谱线重叠,优化校准曲线,提高分析方法准确度。各组分校准曲线线性相关系数R²在0.9940~0.9999之间。按照实验方法熔融JRRM507、JRRM803、JRRM129 3个标准样品,进行方法精密度和熔片精密度试验,结果表明重复性均能达到GB/T 21114—2007要求。按照实验方法选择镁铬矿、高岭土、铝土矿3类标准物质进行正确度验证,VS P14/3、UNS KK、ZBK394标准物质中MgO、ZrO₂、Na₂O、ZnO、NiO、Fe₂O₃、MnO、Cr₂O₃、V₂O₅、TiO₂、P₂O₅、SiO₂、CaO、K₂O、Al₂O₃等主次组分的测定结果与认定值相吻合。

Determination of fifteen components in siliceous,aluminum, magnesia and chrome refractory materials by X-ray fluorescence spectrometry with fusion sample preparation

The analysis of MgO, Na₂O, Fe₂O₃, MnO, Cr₂O₃, TiO₂, P₂O₅, SiO₂, CaO, K₂O, Al₂O₃ in siliceous, aluminum, magnesia and chrome refractory materials usually adopts EDTA titration method, spectrophotometry and flame atomic absorption spectrometry. However, these methods are cumbersome and time-consuming. On the other hand, if X-ray fluorescence spectrometry is employed, different fusion methods and calibration curves are required for four kinds of refractory materials. In order to unify the sample preparation method of four kinds of refractory materials and simultaneously determine the major and minor components (i.e., MgO, ZrO₂, Na₂O, ZnO, NiO, Fe₂O₃, MnO, Cr₂O₃, V₂O₅, TiO₂, P₂O₅, SiO₂, CaO, K₂O, Al₂O₃) using the same set of calibration curves, three sets of foreign standard sample of refractory material were selected to optimize the fusion sample preparation conditions such as melting temperature, time and dilution ratio. The voltage, current, collimator and other conditions of each element were obtained by peak position and intensity scanning to achieve the best sensitivity and resolution. The pulse width was determined by scanning PHA to improve the accuracy. The theoretical α coefficient was used to correct the absorption enhancement effect among elements. The proportional method was adopted to calculate and calibrate the overlapping of spectral lines, thus optimizing the calibration curve and improving the accuracy of analysis method. The linear correlation coefficients (R²) of calibration curves of components were between 0.9940 and 0.9999. Three standard samples (JRRM507, JRRM803 and JRRM129) were fused and determined according to the experimental method. The precision tests of method and melt bead were conducted. The results showed that the repeatability could meet the requirements of GB/T 21114-2007. The correctness verification was performed using three kinds of standard substances (i.e., magnesia-chrome ore, kaolin and bauxite) according to the experimental method. The determination results of major and minor components (including MgO, ZrO₂, Na₂O, ZnO, NiO, Fe₂O₃, MnO, Cr₂O₃, V₂O₅, TiO₂, P₂O₅, SiO₂, CaO, K₂O, Al₂O₃) in standard substances (VS P14/3, UNS KK and ZBK394) were consistent with the certified values.