An assessment of a handheld X-ray fluorescence instrument for use in exploration and development with an emphasis on REEs and related specialty metals
An assessment of a handheld X-ray fluorescence instrument for use in exploration and development with an emphasis on REEs and related specialty metals
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DOI：
10.1007/s00126-013-0493-0
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发表时间：
2014-12-01
影响因子：
4.8
通讯作者：
Grattan, K.
中科院分区：
文献类型：
--
作者：
Simandl, G. J.;Stone, R. S.;Grattan, K.
手持式（便携式）X射线荧光（pXRF）仪器设计用于贱金属、贵金属和特种金属（例如G.稀土元素（REE），Ta和Nb），并允许直接在现场快速决策。本文利用三种地球化学标准和一种硅空白的分析数据，评价了pXRF技术在特殊金属勘探中的技术优点和局限性：盖瑟斯堡国家标准与技术研究所的标准参考物质NIST 2780，蒙古中央地质实验室的有证参考物质“TRLK”稀土矿“CGL 124”，参比铌矿石OKA-1（CANMET）;和来自AlphaAesar（WardHill，MA，USA）的描述为Si（IV）氧化物（99.8%，基于金属）的二氧化硅空白。这些数据是在近2年的时间里作为几个不同的特种金属相关项目的副产品获得的，这些项目使用相同的pXRF仪器和相同的设置。使用pXRF仪器读数的平均浓度与标准品的报告认证值之间的差异百分比（%diff）确定仪器分析准确度。使用相对标准偏差百分比（%RSD）作为精密度指标。较小的%差异和%RSD表示更准确和精确的数据，并且pXRF的准确度和精确度强烈依赖于所用标准品中的元素浓度。盒须图用于说明对应于单个标准品的pXRF数据集的特征（平均值、上四分位数和下四分位数以及范围）。pXRF测定值相对于单个标准品认证值的偏倚（低估/高估）也在这些图中描述。本研究表明，pXRF能够产生Si、K、Al、Fe、Ca、Ti、Pb、Zn、Sr、Ag、Cd、Th、Sb、P、S、Mo、Mn、Mg、As、Nb、Rb、La、Ce、Pr、Nd和Y的读数，在所测量的三种标准品中的至少一种标准品的报告认证值的10% RSD范围内（取决于该标准品中的浓度）。该仪器能够提供Nd、Pr、Ce、La和Y的相对准确和精确的数据（%diff，
Handheld (portable) X-ray fluorescence (pXRF) instruments are designed for use in the exploration for base metals, precious metals, and specialty metals (e. g. rare earth elements (REE), Ta, and Nb) and allow rapid decision-making directly in the field. This paper evaluates the technical merits and limitations of pXRF technology in the exploration for specialty metals using data generated from the analysis of three geochemical standards and a silica blank: Standard Reference Material NIST 2780 from the National Institute of Standards and Technology, Gaithersburg; the Certified Reference Material "TRLK" Rare Earth Ore "CGL 124" from the Mongolia Central Geological Laboratory; the Reference Niobium Ore OKA-1 (CANMET); and a silica blank described as Si (IV) oxide (99.8 % on metal basis) from Alpha Aesar (Ward Hill, MA, USA). The data was acquired over a period of nearly 2 years as a by-product of several distinct specialty metal-related projects using the same pXRF instrument and the same settings. Instrumental analytical accuracy was determined using the percent difference (%diff) between the average concentrations of the pXRF instrument readings and the reported certified values of the standard. Percent relative standard deviation (%RSD) was used as a measure of precision. Smaller %diff and %RSD indicate more accurate and precise data, and the accuracy and precision of the pXRF depended strongly on the elemental concentrations in the standards used. Box and whisker diagrams were used to illustrate characteristics of pXRF data sets (mean, lower and upper quartiles, and range) corresponding to individual standards. The bias of the pXRF determinations (under/overestimation) relative to certified values of individual standards are also depicted on these diagrams. This study indicates that the pXRF was capable of producing readings for Si, K, Al, Fe, Ca, Ti, Pb, Zn, Sr, Ag, Cd, Th, Sb, P, S, Mo, Mn, Mg, As, Nb, Rb, La, Ce, Pr, Nd, and Y within 10 %RSD of the reported certified value in at least one of the three standards measured, depending on the concentrations within that standard. The instrument was able to provide relatively accurate and precise data for Nd, Pr, Ce, La, and Y (%diff,