粉末压片-X射线荧光光谱法测定含铌多金属矿样中铌

采用粉末压片制样,使用X射线荧光光谱仪对含铌多金属矿样中的铌进行测定。由于含铌的多金属矿标样极少且含量较低,实验选取钽矿石标准样品、矿区具有代表性的化学法定值多个样品,及其他土壤、岩石、多金属矿物标准样品、矿区定值样品混合配制的校准样品,制成一套铌含量5.9～2 700 μg/g、梯度适当的校准样品系列,绘制的铌校准曲线相关系数为0.998 6。采用经验系数和康普顿散射线内标法校正了基体效应,用Omnian 近似定量软件、化学分析法与岩矿鉴定分析,确定了矿区矿物中主要成分SiO₂、Al₂O₃、CaO、MgO、K₂O、Pb、Zn、Cu、Fe、Zr、Mo、Rb、Hf、Th、U、Ti、Ga及稀土的最高允许量。综合考虑样品基体对铌检出限的影响,实验选取8个标准样品计算出检出限的平均值为1.62 μg/g。对岩石标样进行精密度考察,结果的相对标准偏差(RSD,n=12)为2.2%。对标准样品及矿区实际样品进行分析,测定值与认定值、实验室内其他方法的测定值及其他实验室的测定值吻合,满足《地质矿产实验室测试质量管理规范》的要求。

Determination of niobium in niobium containing multi-metal ore by X-ray fluorescence spectrometry with powder pressed pellet

A method for the determination of niobium in niobium containing multi-metal ore by X-ray fluorescence spectrometer(XRF) with powder pressed pellet was studied. Since there are quite few niobium containing multi-metal ore and the content of niobium is quite low, tantalum ore certified reference materials, representative samples in ore area calculated by chemical method ,and calibration samples prepared by soil, rock, multi-metallic minerals certified reference materials and ore samples were selected to prepare calibration sample series with 5.9-2 700 μg/g niobium. The correlation coefficient of calibration curve was 0.998 6. Empirical coefficients and Compton scattering line internal standard method were applied to correct matrix effect. Omnian software for approximate quantitative analysis, chemical analysis and rock and mineral identification were used to determine the highest allowable amount of SiO₂, Al₂O₃, CaO, MgO, K₂O, Pb, Zn, Cu, Fe, Zr, Mo, Rb, Hf, Th, U, Ti, Ga and rare earth in the ore. By considering the influence of matrix to the detection limit of niobium, the average detection limit of 8 certified reference materials was 1.62 μg/g. The precision of rock certified reference material was investigated with the RSD (n=12) of 2.2%. Standard sample and practical ore sample were analyzed. Tested value and certified value, the tested value by other methods of internal laboratory and the tested value by other laboratories were consistent with each other, meeting the requirement of Quality Management Practices of Geology and Mineral Resources Laboratory.