碱熔-电感耦合等离子体原子发射光谱法测定钒渣中钒硅钙镁铝锰铬钛磷

钒渣是制备钒氧化物、钒金属材料等高钒基体产品的关键原料,快速准确掌握其成分含量是调控工艺参数、确保产品质量的前提条件。使用化学湿法检测效率低、周期长,而X射线荧光光谱法(XRF)难以满足微量元素测定需要,为此建立了碱熔-电感耦合等离子体原子发射光谱法(ICP-AES)同时测定钒渣中V、Si、Ca、Mg、Al、Mn、Cr、Ti、P的分析方法。重点试验了熔剂的配比及用量、反应温度及时间等熔解条件,最终优选0.10 g钒渣样品采用0.80 g碳酸钾-硼酸(K₂CO₃-H₃BO₃,质量比为1∶1)混合熔剂在950 ℃熔融反应25 min的方式分解样品;通过光谱干扰试验,优选出灵敏度适宜且未受共存组分光谱重叠干扰的V 289.332 nm、Si 251.611 nm、Ca 317.933 nm、Mg 285.213 nm、Al 396.152 nm、Mn 293.306 nm、Cr 267.716 nm、Ti 323.904 nm、P 178.284 nm作为待测元素分析谱线,满足同时测定钒渣中常量和微量元素的需要;试验了在构成复杂的钒渣组分与碱金属熔剂共存体系下,连续背景叠加、基体效应等影响因素对分析谱线的干扰,通过基体匹配和同步背景校正法消除其影响,并且优化分析谱线的积分区域、背景校正区域等检测条件,改善了方法检测性能。结果表明:测定范围为0.10%～20.0% V,0.10%～15.0% Si,0.10%～10.0% Ca、Mg、Al、Mn、Ti,0.10%~5.0% Cr,0.01%~1.0% P;校准曲线线性相关系数不小于0.999 6;方法检出限为0.000 6%～0.002 7%。按照实验方法测定钒渣中各组分,质量分数大于0.1%时结果的相对标准偏差(RSD,n=8)小于1.0%,质量分数小于0.1%时结果的相对标准偏差(RSD,n=8)小于3.0%;钒渣标准样品的测定值与标准值相吻合。

Determination of vanadium,silicon,calcium,magnesium,aluminum,manganese,chromium,titanium and phosphorus in vanadium slag by inductively coupled plasma atomic emission spectrometry after alkali fusion

Vanadium slag is the key raw material to prepare high-vanadium products such as vanadium oxides and vanadium metal materials. The rapid and accurate determination of composition contents is the precondition for the adjustment and control process parameters to ensure the product quality. The detection efficiency of chemical wet method is low and the testing period is long. X-ray fluorescence spectrometry(XRF) is difficult to meet the determination requirements of micro elements. Therefore, the analysis method for the simultaneous determination of V, Si, Ca, Mg, Al, Mn, Cr, Ti and P in vanadium slag by inductively coupled plasma atomic emission spectrometry (ICP-AES) after alkali fusion was established. The conditions for sample fusion, such as mixture ratio and dosage of flux, reaction temperature and time, were studied. The following sample decomposition method was finally selected: 0.10 g of vanadium slag sample was fused with 0.80 g of potassium carbonate-boric acid mixed flux (mass ratio of 1∶1) at 950 ℃ for 25 min. Through spectral interference experiments, the suitable analytical lines for each analyte with appropriate sensitivity yet without suffering from spectral interference were selected: V 289.332 nm, Si 251.611 nm, Ca 317.933 nm, Mg 285.213 nm, Al 396.152 nm, Mn 293.306 nm, Cr 267.716 nm, Ti 323.904 nm and P 178.284 nm. These analytical lines could meet the requirements for the simultaneous determination of major and micro elements in vanadium slag. Spectral interference from continuous background overlapping and matrix effect in coexistent system of vanadium slag and alkali metal fluxes was investigated. The influence was eliminated by matrix matching and synchronous background correction. Moreover, the working conditions such as analytical line integral area and background correction area were optimized to improve the testing performance of method. The results showed that the determination ranges were: 0.10%-20.0% V; 0.10%-15.0% Si; 0.10%-10.0% Ca, Mg, Al, Mn and Ti; 0.10%-5.0% Cr; 0.01%-1.0% P. The linear correlation coefficients of the calibration curves were not less than 0.999 6. The limits of detection were between 0.000 6% and 0.002 7%. The content of each components in vanadium slag were determined according to the experimental method. The relative standard deviations (RSD, n=8) of component with content higher than 0.1% was less than 1.0%, and the RSDs (n=8) of components with content less than 0.1% was less than 3.0%. The determination results of certified reference material of vanadium slag were in good agreement with the certified values.