Geochemical analysis of marine sediments using fused glass disc by X-ray fluorescence spectrometry

A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard （for the trace elements）. The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% （n=12）.

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.

Determination of Content of Eight Elements in Metal Coating Smeared on Waste Plastics by X-ray Fluorescence Spectrometry

X-ray fluorescence spectrometry was used to detect the content of eight elements in metal coating smeared on waste plastics,and effects of sample cups,elements in plastic substrate,and interaction of elements in metal coating on detection results were analyzed. The results show that the RSD of the method used to detect element content in the metal coating smeared on the waste plastics ranged from 0.008% to 0.044%; the determination range of the eight elements was 0.002%-52.0%,and their detection limit ranged from 0.0002% to 0.0008%. The determination results of X-ray fluorescence spectrometry were consistent with that of ICP-AES. The method can provide technical support for the determination of damage and pollution caused by metal coating smeared on waste plastics.

Quantitative Analysis of FeMo Alloys by X-Ray Fluorescence Spectrometry

A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation of homogeneous fused discs was achieved by employing an automated fusion machine equipped with specially designed O2-blowing nozzles, which used lithium tetra-borate as flux with the addition of lithium nitrate (LiNO3) as oxidizer. The calibration curves of Mo and Fe were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory accuracy and precision, utilizing the corrections of the matrix effects and line overlap. It was confirmed that the newly proposed method of preparing fused glass discs of FeMo alloys can replace the conventional wet chemical analyses requiring the labor intensive and time consuming procedure.

Technological and Environmental Behavior of Coal Fly Ash in Lime-Based Materials

Coal fly ash is considered an industrial by-product derived from coal combustion in thermal power plant. It is one of the most complex anthropogenic materials. Its improper disposal has become an environmental concern and resulted in a waste of recoverable resources. The aim of this paper is to study the physico-chemical characteristics of binders based on coal fly ash and lime in order to develop an eco-cement. The various characterization tests carried out are X-ray fluorescence, X-ray diffraction, compressive strengths, thermophysical properties and setting time. X-ray fluorescence and X-ray diffraction were used to determine the chemical composition and phases of fly ash, lime and binders. This allowed us to see that the chemical composition of fly ash is similar to that of cement. Compressive strengths of mortars containing 20%, 40%, 60% and 80% of fly ash have shown that fly ash has a long-term positive effect which might be related to a pozzolanic activity. The L3 binder consisting of 60% of coal fly ash and 40% lime has a higher compressive strength than the others. The binder setting start time is greater than that of cement but shorter than that of lime. The study of the thermophysical properties of the L3 binder shows that it has a higher thermal resistance than cement mortar. Moreover, it heats up less quickly because of its low effusivity compared to that of the latter. This analysis highlighted the principal characteristics that must be taken into account to use coal fly correctly in lime-based materials.

Physico-Chemical Characterization and Speciation of Sulphur of Nigerian Coal Samples

Studies of physico-chemical characterization, and chemical speciation of sulphur of seven Nigerian coal samples have been undertaken. The seven coal samples originated from South-east, North-central and North-east of Nigeria where there are proven economic deposits of this mineral. Moisture content, bulk density, percentage ash and loss of mass on ignition of all the coal samples were determined. The ultimate analysis of the raw coal, the corresponding coal ash as well as sulphur content of all samples were carried out with the aid of X-ray fluorescence technique (XRF). The major elements were Fe, Ca and S while the minor metals were K, Sc, Zn, Ni, Ti and Zr. Other metals including Ga, Cu, Mn, Cr and V were found in traces. The Nickel/Vanadium ratio which is a means of providing information on the source rock depositional environment ranged between 8.8 - 32.9. Three different source rock depositional environments were deduced for the coals from their nickel/vanadium ratios, while the calculated values of V/(V+Ni) suggested that they were all formed under oxic condition. The three chemical species of sulphur, sulphate, pyritic and organic sulphur in the seven coal samples were determined using the ASTM method.

X-ray fluorescence spectrometry determination of open-hearth furnace slag by pressed powder briquetting

A rapid analysis method of determining content of eight compounds of open-hearth furnace slag was developed using X-ray fluorescence spectrometry and pressed powder briquettes. Matrix effect was corrected using theoretical alpha coefficient. Grains-size effect was eliminated by optimized sample preparation technique parameters. Mineral effect was corrected with standard curve of specially made standard samples. The analysis results of TiO2, TFe, SiO2, MgO, Al2O3, CaO, MnO and P2O5 in slag samples showed that both precision and accuracy are comparable with that of chemical method.

X射线荧光光谱技术发展现状及在煤质检测中的应用

X射线荧光光谱法(XRF)无源检测技术以分析速度快、非破坏性、分析元素范围广等优异特性,在检测领域已得到广泛应用。基于XRF的研究现状,对XRF技术的发展进程、基本原理及分析方法、仪器构成与分类等进行了详细阐述,明晰了XRF特征X射线产生机理与分析原理,以及定性分析、半定量分析、定量分析的特点,对比分析了不同类型XRF光谱仪的原理、组成、技术特性及应用领域。分析了XRF在煤质检测中的发展与应用,研究结果表明:采用压片法与熔片法两种方法处理样品,应用XRF光谱仪分析煤灰中常量元素及微量元素可得到较好的结果精密度、准确度;XRF在线分析技术受分析原理、数据模型、环境因素等限制与影响,当前主要用于对检测结果准确度要求不高的煤矿、选煤厂生产原煤、产品的质量控制,以及煤矸石识别。针对在煤质检测应用过程中的问题,从原理分析、基体效应、仪器设备及操作安全四方面剖析了现阶段XRF在煤质检测应用中的技术局限性;结合XRF的优势与不足,指出XRF应与其他光谱或图像技术联用拓宽煤质可测指标范围,通过“数智”结合提高煤质在线检测或离线检测的准确性和可靠性,为助力我国煤炭清洁高效利用,实现智慧工业与“双碳”目标,提供坚实的分析测试技术与硬件基础。

氢化物发生-原子荧光光谱法测定煤中砷含量测量不确定度分析与评定

使用氢化物发生-原子荧光光谱法检测煤中砷含量的不确定度,进一步探讨不确定度的根本原因,最终结果的精准度受到样品处理、检测试剂、检测环境等诸多因素的影响。创新设计一个数学模型,从测量重复性、试剂溶液浓度、煤样处理等多个角度入手,对不确定度的根本因素展开研究探讨,核算出煤中砷的合成标准不确定度是0.133 ug/g,样品砷含量检测数据是(1.75±0.27)μg/g,包含因子k=2。各测量不确定度的核心影响因素有三个:其一是标准工作曲线拟合,其二是测量重复性,其三是煤样处理,因此在测定时应加强样品处理、试剂溶液、测定条件等影响因素的控制。

原子荧光光谱法测定煤中锗含量的不确定度评估

论述了氢化物原子荧光光度法测定煤中锗含量的测定过程和数学模型,并分析各分量不确定度的来源;结果表明,原子荧光法测定煤中锗的不确定度主要引入来源分别为工作曲线拟合、方法回收率和样品重复测定;其中工作曲线拟合引入不确定度最大,当煤中锗含量为10.28μg/g时,合成标准不确定度为0.302 6μg/g,扩展不确定度为0.605 2μg/g(k=2)。

能量色散X荧光光谱法测定煤灰成分方法研究

采用能量色散X荧光光谱法测定煤灰成分,与化学分析法相比较则所需的设备相对简单且快速测得结果、操作更简单及更为经济有效。介绍采用能量色散(EDXRF)测定国能神优煤灰中多种灰成分的方法,针对灰样制备过程、基体效应、能谱模式等试验条件进行探讨,并通过多个煤灰标准样品进行核验,指出灰样制备过程采用研磨通过0.1 mm标准筛后于(815±10)℃灼烧1 h的标准方法进行,基体效应采用多元线性回归去除灰成分中硅与铝、磷与钙、钾与钙、铁钛钙间4种元素相互干扰情况,选择80 kcps-480 s能谱模式可通过多个煤灰标准样品检测,其结果与认定值的误差均在不确定度要求的范围内,数据准确,能够适用于目前实验室快速测定煤灰成分的要求。

X荧光光谱法(压片法)在煤灰成分分析中的应用

煤灰成分是影响燃煤发电效率的重要指标。为了实现准确和快速地检测煤灰成分,利用X荧光光谱法(压片法)对几种典型煤灰样品进行分析,并探讨该方法的可行性和优点。研究结果表明,X荧光光谱法(压片法)在煤灰成分分析中的应用具有高效、准确、快速、非破坏性等优点,并且能够同时检测多个元素的含量,具有广泛的应用前景。

X射线荧光光谱法测定煤中砷磷氯

随着国家环境保护意识的加强，进口煤环保项目要求逐渐提上日程，砷、磷、氯是主要项目之一。实验通过筛选，采用硼酸作为粘结剂，与煤炭样品直接混匀、压片制样，利用X射线荧光光谱法（XRF）测定煤中的砷、磷、氯含量，所制样片强度高，所建方法的测定范围：0．0005％～0．0051％（砷）、0．015％～0．11％（磷）、0．007％～0．092％（氯）。方法的相对标准偏差（RSD，n=11）分别为6．2％（砷）、1．7％（磷）、2．5％（氯）。用煤炭标准样品验证实验方法，测定值与参考值一致；与原子荧光光谱法进行了砷对照试验，两种方法的测定结果吻合较好。实验方法可用于进口煤中砷、磷、氯的快速测定。

熔片制样-X射线荧光光谱法测定煤灰样品中主次量组分

采用混合熔剂熔融制备样片,用AxiosX射线荧光光谱仪测定煤灰样品中二氧化硅、氧化铝、氧化铁、氧化镁、氧化钙、氧化钠、氧化钾、二氧化钛、二氧化锰、五氧化二磷和三氧化硫等11种组分。重点研究了熔样比、熔样温度和标准样品的制备,解决了分析硫的难题。用基本参数法校正基体效应,分析方法的精密度(RSD,n=10)各组分均小于3%。用煤灰国家一级标准物质验证,结果与标准值相符。

X射线荧光光谱法同时测定煤灰中的12种成分

采用熔融制样法,用X射线荧光光谱法同时测定煤灰中的常量、少量和微量成分SiO2,Al2O3,Fe2O3,CaO,SO3,TiO2,K2O,Na2O,P2O5,MgO,MnO,BaO。选用混合熔剂并加入氧化剂的方式降低熔融温度,解决了硫的准确测量问题。同时通过选用土壤等标准样品解决了煤灰成分标准样品不足的问题。应用可变理论α系数及固定α系数法进行基体效应校正,所得结果与化学法的分析结果相符合。

微波消解-冷原子荧光法测定煤中痕量汞

微波消解技术具有样品溶解完全、污染少、节约试剂和方便快捷等特点。文章采用微波消解预处理煤样 ,并用冷原子荧光法测定样品中的痕量汞。采用硝酸 盐酸 氢氟酸消解体系 ,进行了微波消解条件的选择 ,并考察了载气流量、屏蔽气流量、负高压和干扰等对测定的影响。在选定的操作条件下 ,汞的检出限为0 0 3ng·mL-1,相对标准偏差 (n =7)小于 5 %。方法准确、快速和方便 ,利用国家标准参考物质煤飞灰GBW 0 84 0 1验证了方法的准确度 。

高压制样X-射线荧光光谱法测定煤样品中17种元素和灰分

采用自制的高压制样模具,在1400 kPa压力下直接压制煤样品,解决了由于煤样品粘结性差难以直接压制成型的难题。用电子显微镜对高压样片(1400 kPa)和常规压片(400 kPa)作了表面形态的比较,高压制备的样片表面致密、平整、光滑、不掉粉末。由于煤国家标准样品中定值的元素少,为了增加煤标样中可测定元素,以ICP-AES多次分析结果的平均值作为标准值,用高压制样建立了波长色散X射线荧光光谱测定煤样品中17个主次微量元素的分析方法,绝大部分组分的检出限较常规压力制备的样品有所改善,大部分组分的精密度都低于1%,制样的重现性好,X荧光的测定值与化学值基本相符。特别指出的是:使用SiKα测量强度和煤样品中的灰分含量建立的校准曲线,其RMS为0.9441,可直接用于测定煤样品中的灰分。

X射线荧光光谱法同时测定煤中砷硫磷氯

采用人工混配有限煤炭标准样品粉末直接压片制样，X射线荧光光谱仪同时测量煤中的砷、硫、磷、氯。优化了样品粒度、样品量、助磨剂、制样压力和保压时间等实验条件，用可变α系数法进行基体校正。方法测定范围为As0．0015％-0．0051％、S0．21％-1．44％、P0．003％～0．096％、C10．01％-0．11％；检出限为As 1．2μg／g、S22μg／g、P2．1μg／g、C12．0μg／g。与标准方法对照，结果基本一致。方法快速、简便，满足了煤炭检验需要。

微波消解-氢化物发生原子荧光光谱法和质谱法测定高有机质无烟煤中汞砷的可行性研究

微波消解技术适用于处理大部分煤炭样品,但对于高有机质含量的无烟煤样品,因其煤化程度高,含有多种复杂的高分子有机化合物,应用现有的消解技术不能将其完全消解。本文对微波消解的实验条件包括消解试剂、消解温度及消解时间进行优化,确定了适合处理高有机质无烟煤的消解体系,评价了采用HG-AFS和ICP-MS测定其中总汞和总砷含量的可行性。结果表明,以硝酸-硫酸-氢氟酸（6∶4∶0.5）作为微波消解试剂,消解温度达205℃,保持30 min可将高有机质含量的无烟煤彻底分解,其中硫酸对无烟煤的消解起到了关键作用;ICP-MS与HG-AFS对汞的检测结果一致,回收率都达到98%以上,但由于砷的化学形态复杂,有机态砷不能全部转化无机态砷使得HG-AFS对砷的检测结果偏低。因此,对于有机质含量特别高（81%-90%）的煤炭样品,微波消解可将其彻底转化为溶液,用ICP-MS可以准确定量其中的汞和砷,而HG-AFS不能作为检测砷的有效手段。

氢化物发生-原子荧光光谱法测定煤样中的硒

采用氢化物发生原子荧光光谱法测定了煤样中的总Se。煤样先用高压闷罐强酸消解的方法进行处理 ,所得消解液经 6mol/LHCl将Se(Ⅵ )还原为Se(Ⅳ ) ,然后进行测定。标准工作曲线的线性范围为 0～ 40 0 μg/LSe,检测限为 0 .40 μg/LSe。用标准参考物质煤飞灰对方法进行了验证 ,所得总Se含量与标准值相符 ,对w为 1 0 - 6级Se的 4次测定 ,RSD≤ 4.5 %。