Quantitative energy-dispersive X-ray fluorescence analysis for unknown samples using full-spectrum least-squares regression

The full-spectrum least-squares(FSLS) method is introduced to perform quantitative energy-dispersive X-ray fluorescence analysis for unknown solid samples.Based on the conventional least-squares principle, this spectrum evaluation method is able to obtain the background-corrected and interference-free net peaks, which is significant for quantization analyses. A variety of analytical parameters and functions to describe the features of the fluorescence spectra of pure elements are used and established, such as the mass absorption coefficient, the Gi factor, and fundamental fluorescence formulas. The FSLS iterative program was compiled in the C language. The content of each component should reach the convergence criterion at the end of the calculations. After a basic theory analysis and experimental preparation, 13 national standard soil samples were detected using a spectrometer to test the feasibility of using the algorithm. The results show that the calculated contents of Ti, Fe, Ni, Cu, and Zn have the same changing tendency as the corresponding standard content in the 13 reference samples. Accuracies of 0.35% and 14.03% are obtained, respectively, for Fe and Ti, whose standard concentrations are 8.82% and 0.578%, respectively. However, the calculated results of trace elements (only tens of lg/g) deviate from the standard values. This may be because of measurement accuracy and mutual effects between the elements.

Elemental and proximate analysis of coal by x-ray fluorescence assisted laser-induced breakdown spectroscopy

Although laser-induced breakdown spectroscopy(LIBS),as a fast on-line analysis technology,has great potential and competitiveness in the analysis of chemical composition and proximate analysis results of coal in thermal power plants,the measurement repeatability of LIBS needs to be further improved due to the difficulty in controlling the stability of the generated plasmas at present.In this paper,we propose a novel x-ray fluorescence(XRF) assisted LIBS method for high repeatability analysis of coal quality,which not only inherits the ability of LIBS to directly analyze organic elements such as C and H in coal,but also uses XRF to make up for the lack of stability of LIBS in determining other inorganic ash-forming elements.With the combination of elemental lines in LIBS and XRF spectra,the principal component analysis and the partial least squares are used to establish the prediction model and perform multi-elemental and proximate analysis of coal.Quantitative analysis results show that the relative standard deviation(RSD) of C is 0.15%,the RSDs of other elements are less than 4%,and the standard deviations of calorific value,ash content,sulfur content and volatile matter are 0.11 MJ kg,0.17%,0.79% and 0.41%respectively,indicating that the method has good repeatability in determination of coal quality.This work is helpful to accelerate the development of LIBS in the field of rapid measurement of coal entering the power plant and on-line monitoring of coal entering the furnace.

A TOTAL CONTENT X—RAY FLUORESCENCE METHOD FOR COPPER PROSPECTING

A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of a Cu deposit. Applications of the technique in Northeast China are presented.

L-shell x-ray fluorescence relative intensities for elements with 62≤Z≤83 at 18 keV and 23 keV by synchrotron radiation

The relative intensities of L-subshell x-ray fluorescence(XRF)for elements with atomic numbers 62≤Z≤83 were measured at two excitation energies,18 keV and 23 keV,using a synchrotron radiation source at a beamline of the Synchrotron Light Center for Experimental Science and Applications in the Middle East(SESAME),Jordan.The experimentally measured results of the relative intensities were compared with the calculated results using the subshell fluorescence yield and the Coster-Kronig transition probabilities recommended by Campbell and the values based on the Dirac-Hartree-Slater model by Puri.The experimental and theoretical results are in agreement.In this work,L XRF relative intensities for the elements Sm,Gd,Tb,Er,Ta,W,Re,Hg,Pb and Bi at energies of 18 keV and 23 keV were measured.

X-RAY FLUORESCENCE SPECTRA ANALYSIS ON THE STRUCTURE AROUND Ti^(4+) OF BaO-SiO_2-B_2O_3-TiO_2 SYSTEM GLASSES

The structure around Ti^(4+) in Bao-SiO_2 -B_2O_3-TiO_2 had been studied by X-ray fluorescence spectra. The results show that the Ti^(4+) mainly exists in the [TiO_4] and enters the network of [SiO_4]. [TiO_4] has the tendency to change to [TiO_6] with the increase of TiO_2 con-tent. When the TiO_2 content increases to about 20mol% the tendency reaches its maximum.

Specimen Variation Effects on XRF Analysis by the Monte Carlo Method: Thicknesses, Densities and Particle Sizes

This theoretical study conducted an X-ray fluorescence (XRF) analysis on specimen variation, with emphasis on variations on the thicknesses, density and particle sizes of specimens. The theoretical formula for X-ray fluorescence intensity was derived. These specimen variations were simulated using Monte Carlo Neutron-Particle Transport Code MCNP5. The Cu element X-ray characteristic peak counts were calculated. These variations made a conspicuous impact on the fluorescence intensity X-ray characteristic, in terms of theoretical formulas and calculations. There was a nonlinear relationship between thicknesses and count, except for thin specimens. As the density increased, the count increased in an exponential form for the saturated thick specimens. When the density reached 1 g.cm-3 , the count remained constant. The matrix materials (moisture) could increase the matrix effects. The higher the moisture was, the greater the matrix effect was. Specimen particle size also affects these measurement results. Hence, these specimens must be prepared before measurement. The calculations were consistent with the theoretical formulas.

一种校正XRF光谱基体吸收效应的新方法

根据校正XRF光谱基体吸收效应的基本理论,提出了一种用基本参数法校正基体吸收效应的新方法,该法既不需要标准,又对样品和衬底靶无特别要求,仅用一些基本的物理参数(ω,J,τ)和荧光强度的测量值便可算得样品中待分析元素的含量,方便简单。用岩石标准SY-2,SY-3和MRG-1检验该法,其结果与文献报道的值相符。

超高灵敏XRF测定岩矿中的痕量砷

本文提出了在硫酸介质中，以锌粒还原砷产生氢化物，铁氰化钾吸收，加入高价钱沉淀，微孔滤膜过滤制成薄样，ＸＲＦ测定痕量砷的分析方法．

XRF法检验出口硅铁产品中元素硅和铝的含量

对XRF法测定硅铁中硅和铝元素检测方法进行了理论分析和试验探讨 ,阐述了其规定试验条件下的可行性、准确性和优点 ,同时阐明环境及其他因素对测定的影响 ,使之成为更有效的检测方法。

Application of a Portable XRF Spectrometer for <i>In-Situ</i>and Nondestructive Investigation of Pigments in Two 15th Century Icons

A simple portable X-Ray Fluorescence (XRF) spectrometer was successfully used for in-situ and nondestructive identification of the painting materials in two 15th century icons from the Onufri Museum in Beart, Albania. The spectrometer is based on a low power X-ray tube, a thermoelectrically cooled Si PIN detector and the spectrum acquisition system. It was assembled and adjusted at our laboratory for the investigation of the icons. A small number of pigments were clearly identified by X-Ray Fluorescence (XRF) measurements in both icons. This includes Lead white for the white color, gold and yellow ochre for the yellow color, red lead, cinnabar and red ochre for the red color, as well as cooper based pigments for the green color. At the same time, the investigation raised some new questions that need further investigations by the use of additional analytical techniques. The results show that in both icons are used similar pigments, which are in accordance with the Byzantine icon painting tradition.

XRF聚丙烯膜在X荧光分析粉末制样法中的应用

建立了适用于粘性差,分析面易开裂、易脱落或不易烘干含挥发组分粉末样品的新型压片方法,通过实验确定了最佳的XRF聚丙烯膜厚度和塑料环尺寸。试验结果表明:XRF聚丙烯膜结合塑料环压片效果良好,采用本方法压片并建立标准曲线后,分析样品与化学分析结果一致,目前已用于日常检测分析中。该方法的应用实现了在压样时,试样片表面平整、光滑;在抽真空时,试样片不开裂、不掉粉末,不污染真空室;在检测分析时,试样片在真空室内不挥发含酸等组分,不会对分光晶体造成腐蚀。

Soil Clay Mineralogical Phase Analysis of Ganges Floodplain Soils by XRD and XRF

Soil minerals study is vital in terms of investigating the major soil forming compounds and to find out the fate of minor and trace elements in soils. It is also essential for the soil-plant interaction purpose. To identify soil mineral phases especially clay minerals, X-ray diffraction (XRD) has been a popular technique. The clay mineralogical information of soils in Bangladesh is limited, especially in Ganges flood plain region (Agro Ecological Zone (AEZ) 12 and 13). Therefore, to overcome this limitation, in this study, we performed XRD analysis of <2 mm fractions soil samples of AEX 12 and 13. However, identifying mineralogical phases by XRD in <2 mm fractions soils is not so straight-forward due to many practical problems. We fully matched only two mineralogical phases in all the soil samples which is quartz and potassium-Aluminum-Silicate. However, the full XRD peaks indicate that more minerals are also present, but due to heterogeneity of soils samples, it is difficult to find other minerals phases by only XRD peak of <2 mm fractions. Therefore, to find more information about mineralogical phases, we performed XRF analysis that provides the elemental composition of minerals phase as oxide. XRF analysis indicated the presence of secondary minerals like illite and chlorite. The presence of high percentage Fe oxide not only indicated the iron mineral phase (goethite and ferrihydrite) but also indicated iron rich high charge smectite minerals (beidellite). The presence of iron rich smectite minerals in the Ganges sediments reported in several previous studies. Thus, we concluded that only XRD in <2 mm fractions of soils is not adequate to identify the mineralogical phases of soil samples. Others analyses like XRF, XRD in <2 μm fractions will be necessary to locate an entire image of soil mineralogical phases.

XRF Standardless Comparison of Mining Head and Tail Grades to Screen and Display Ore Processing Recoveries

Separation of target elements or minerals from their host rock or ore is essential to successful mining operation. The inevitable loss of a portion of the desired material that accompanies each step in the extraction process must be documented to develop the operational protocol. Superposition of the characteristic X-ray fluorescence spectra of head (crushed rock ore particles, pre-processing) and tail (post-processing particles) samples provides a direct visual comparison of relative peak sizes, and thereby the relative concentrations, of elements of interest. If the head and tail peaks are identical, none of the element was recovered in the extraction process. At the other extreme if the tail peak “flat lines”, i.e., there is no peak, there was 100% recovery of that element. Standardless visual comparison is valid if the same mass of identical starting material is incorporated into the head and tail sample analysis pucks, and XRF analytical conditions are identical. The considerable time and expense of acquiring and calibrating the standards associated with XRF analysis of 75 or more elements are avoided, a significant advantage during initial broad screening of an experimental extraction procedure. Full quantitation by XRF or an alternate technique can proceed at a later project stage, if desired. The approach retains and presents all features of the original data, thus eliminating questions about data quality, standards and their calibration, and data manipulation in processing from raw counts to concentrations in printout tables. This form of display is ideal for both the mining professional and such less technical groups as corporate staff, investors, regulators, and the public. Examples presented herein are for heap leaching;the protocol can be applied as well to any of the other traditional ore processing and beneficiation procedures, e.g., gravity concentration, magnetic and electrical separation, froth flotation, and ore sorting.

方法标准验证实验数据中离群值的识别

对方法标准验证实验中测量数据进行合格性审核,对于后续方法精密度计算是一个重要环节。文献中识别离群值的Grubbs法、Dixon法等经典方法有时不能满足要求。探讨了用稳健统计法识别离群值的可行性。基于2套文献数据和XRF方法标准验证实验精密度测量数据,对Grubbs法、Dixon法、Mandel h检验法、质控指标法和稳健统计法(四分位法、迭代法、合格数据范围判定法)进行了比较。结果表明:稳健统计法可有效识别离群值。但四分位法存在过度"检出"现象。综合考虑多种方法识别结果有利于提高离群值判定结论的可靠性。对于个别难以判断的情形,可借助质控指标、技术要求以及数据是否剔除对实验室间标准偏差的影响进行取舍。

X射线荧光光谱法测定FeCuNbSiB纳米晶合金炉渣中9种组分

提出了用熔融制样-X射线荧光光谱法测定FeCuNbSiB纳米晶合金炉渣中TFe,CaO,MgO,SiO2,Al2O3,MnO,CuO,Nb2O5和TiO2的方法。讨论了玻璃熔片的制备、混合熔剂和脱模剂的用量、基体的吸收和增强效应校正,以及用人工配制的标准样品绘制校准曲线等问题。在最佳的分析条件下,测定了人工配制的标准样品中TFe,CaO,MgO,SiO2,Al2O3,MnO,CuO,Nb2O5和TiO2的含量,11次测定结果的相对标准偏差小于0.7%,所得的分析结果与标准样品的标准值相符合。用此方法分析了FeCuNbSiB纳米晶合金炉渣试样,用同一样品在完全相同条件下制备了11个熔片进行测量,其测定结果的相对标准偏差小于3.0%,所得分析结果与其他方法的测定值相一致。

X射线荧光光谱法在线测定稀土冶炼分离过程中钬铒铥镱

我国稀土冶炼分离过程复杂,但多数稀土企业仍依靠实验室离线分析指导工艺,导致分析结果严重滞后,因此现迫切需要一种高效稳定的稀土在线分析方法。实验应用稀土配分在线分析仪,建立了一种在线测定稀土冶炼分离过程中Ho、Er、Tm、Yb配分含量的方法。将采样管置于串级萃取槽水相分隔室内,在蠕动泵作用下将样品输送至分析区域,通过X射线荧光光谱法(XRF)进行检测和数据记录。实验将XRF测试条件优化为电压40kV、电流600μA、测试时间60s,模拟现场工况条件下优化蠕动泵泵速为250r/min,并采用基本参数法消除元素间吸收增强效应。样品11次测定结果的相对标准偏差(RSD)小于0.4%,实验室模拟及现场在线测试结果与电感耦合等离子体原子发射光谱法(ICP-AES)的离线分析结果吻合较好,测试结果滞后时间短,完全能够满足稀土冶炼分离过程工艺动态控制的测定需要。

X射线荧光光谱仪及其分析技术的发展

按照获得和分辨特征X射线荧光光谱的方式,X射线荧光光谱仪可以分为波长色散X射线荧光光谱仪(WDXRF)和能量色散X射线荧光光谱仪(EDXRF)两大类。依照这一分类,论述了X射线荧光光谱仪在设备装置和配套方法方面的新状况。X射线荧光光谱仪整机现在向着小型化、智能化、多功能方面发展,仪器各部件也随着研究的深入而得到了更进一步地改进,在这一基础上,仪器可分析元素的含量范围得到了拓展,方法也得到了丰富。目前,X荧光光谱仪开发了微区面分布的元素成像分析方法、高级次谱线分析方法、薄膜分析方法等新的方法,对这些新方法作以介绍,同时也对基本参数法(FP法)的新近发展作了说明。

X射线荧光光谱在海洋地质及矿产资源调查分析中的应用评介

大洋地质与矿产资源调查是我国20世纪80年代以来开展并迅速发展的一项重要科学事业,地质分析技术、特别是X射线荧光光谱(XRF)技术为此做出了重要贡献。文章收集了1982—2019年间X射线荧光光谱在我国大洋地质及矿产资源调查研究中的应用文献共计56篇,文章从船载现场分析、海洋地质标准物质研制及海洋沉积物、大洋多金属结核、海山富钴结壳、海底磷矿岩和深海稀土资源等海底矿产样品分析等几方面评介了X射线荧光光谱技术的应用,特别是X射线荧光光谱在我国船载现场分析和海洋地质标准物质研制中发挥的重要作用。这些成果充分展现了分析技术在地质工作、特别是地质调查和资源评价中的作用和意义。文章强调:高质量、具有国际影响力的海洋地质标准物质是我国海洋地球化学数据及其研究成果的质量保证;船载现场分析是加快海洋地质与矿产资源调查评价进程、提高航次效率的强有力手段。已有成果为今后更高质量、更快速有效地完成海洋地质与矿产资源调查分析任务提供了宝贵经验。全篇引文98篇。

X射线荧光光谱在标准物质和标准方法研究中的应用评介

标准物质研制需要多种高精密度、高准确度方法的综合运用,特别是样品粉碎加工后的均匀性和稳定性检验,更特别强调检测方法的高精密度测量。X射线荧光光谱(XRF)技术是当今地质材料主、次量组分精密度最高、最经济快速、无污染的多元素分析技术,因此在地质标准物质研制中应用广泛并发挥了重要作用。文章从样品均匀性、稳定性、多元素定值分析和标准分析方法制定方面评介了XRF在地质标准物质研制中的应用,也介绍了XRF在国家和行业标准分析方法制定中的应用。特别介绍了XRF在进行均匀性检验实践中的重要发现:样品不均匀误差已成为现代地质分析误差的重要来源,并从地质分析样品粒度随分析技术进步而不断减小的历史演变提出了应进一步降低分析样品(包括标准物质)粒度的建议,使其与XRF、电感耦合等离子体原子发射光谱(ICP-AES)和电感耦合等离子体质谱(ICP-MS)这些当今最重要的现代分析技术相适应。此外,还评介了超细标准物质研制与超细样品分析方面的研究工作,简述了该项研究的意义和可能对整个地质分析发展带来的影响。美国国家标准与技术研究院(NIST)在这方面的研究工作标志着超细标准物质研制和超细样品分析将是地质分析发展的一个重要方向。全篇引文125篇。

X射线荧光光谱法快速测定FeSiB非晶合金薄带中硅、硼、铁

提出了以自制的标准样品,采用单点法绘制校准曲线,利用X射线荧光光谱仪测定FeSiB非晶薄带样品中硅、硼和铁的含量。对于4个FeSiB非晶合金薄带样品中硅、硼和铁进行了10次测定,其分析结果的相对标准偏差分别为0.4%~0.5%、1.3%~4.2%和0.2%~0.4%。方法的分析结果与火花源原子发射光谱法、化学重量法和电感耦合等离子体原子发射光谱（ICP-AES）法的测定值吻合较好。方法快速、简便,薄带样品无需制样,适用于FeSiB非晶合金薄带的快速成分分析。