X-ray Fluorescence Determination Research Articles

Features of the iron determination in dust emissions of gas purification of electrometallurgical production

Features of the iron determination in dust emissions of gas purification at electrometallurgical facilities are considered. The elemental and phase compositions of dust emissions were determined using energy dispersive x-ray fluorescence analysis (EDXRF) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Sample preparation conditions were optimized with allowance for the analytical methods used. The phase composition of dust emissions represented mainly by zincite, zinc ferrite, halite and sylvite was preliminary determined by X-ray phase analysis. Model mixtures were prepared and used to construct calibration dependences taking into account the results of diffractometric studies. A technique for rapid x-ray fluorescence determination of iron in dust emissions of gas purification has been developed. The methods for iron determination tested on real samples of dust emissions of electrometallurgical production demonstrated a satisfactory convergence of the results obtained by EDXRF (Sr = 1.3%) and ICP-AES (Sr = 2.6%).

Mineral, Chemical and Technical Characterization of Altered Pyroxenic Andesites from Southeastern Spain for Use as Eco-Efficient Natural Materials

Climate change is already an undeniable reality, and it is a direct consequence of our society’s lifestyle and the indiscriminate use of certain materials, such as Portland cement, which causes the emission of gases and waste that contributes to the greenhouse effect. The object of this work is to present the results obtained from research on pyroxenic andesites that have become altered to zeolite and their use as alternative, eco-efficient materials that improve the quality of cement through a standardized partial substitution. In this work, four samples of pyroxenic andesites altered to zeolites (PAAZ) and two samples of unaltered andesites (UPA) were analyzed. The methods used in this study are as follows: petrography of thin section (PTS), chemical analysis of X-ray fluorescence (XRF) and phase determination by X-ray diffraction (XRD). Other tests were carried out to determine the quality of the PAAZ from a technical and practical application point of view, such as chemical analysis of pozzolanicity (CPT) at 8 and 15 days, as well as mechanical compression tests at 2, 7, 28 and 90 days. Petrographic and phase analyses show that the original mineral components of the samples such as pyroxene, amphibole, plagioclase and mica were leached and replaced by more than 90% with mordenite and smectite. XRF analyses indicates an anomalous rise in SiO2, a drastic reduction in alumina Al2O3 and a significant increase in alkaline compounds over alkaline-earth compounds in samples of altered pyroxenic andesites (PAAZ) with respect to samples of unaltered andesites (UPA). The pozzolanicity test establishes that the samples of unaltered andesites do not behave like pozzolans at 8 or 15 days; however, altered andesites experienced remarkable pozzolanic reactivity in the same periods. The mechanical compression tests carried out on specimens made with PAAZ and Portland cement showed a growing increase in mechanical resistance from 2 days (15.2 MPa) to 90 days (72.1 MPa). These results suggest that pyroxenic andesites altered to zeolite can be an ideal alternative to partially replace Portland cement, which in turn could contribute to the preservation of the environment and a more rational use of traditional resources.

SORPTION AND X-RAY FLUORESCENCE DETERMINATION OF MICRO QUANTITIES OF SOME TOXIC METALS IN NATURAL OBJECTS AFTER THEIR PRECONCENTRATION ON MODIFIED SILICA GEL

A method for X-ray fluorescence determination of trace amounts of Pb(II), Cd(II) and Hg(II) ions (up to 250 μg/ml) directly in the sorbent phase after their extraction from solutions in a dynamic sorption mode has been developed. Merck silica gel (particle d 0.1-0.2 mm, specific surface 428.61 m2/g), chemically modified with 4-(2-pyridylazo)-resorcinol functional groups in one step, was used as a sorbent. An energy dispersive X-ray fluorescence analyzer with a semiconductor detector "ElvaX" ("Elvatex", Kyiv) was used in the study.
 It was found that the combined analysis of micro quantities of Pb, Cd and Hg by sorption-x-ray fluorescence method after their preconcentration on silica gel with chemically fixed surfactant requires the use of calibration curves for each metal, taking into account the presence of other ions in solutions.
 The developed by us method of sorption-x-ray fluorescence determination of micro quantities of Pb(II), Cd(II) and Hg(II) after their extraction and preconcentration on silica gel with chemically fixed 4-(2-pyridylazo)-resorcinol can be effectively used for the analysis of natural and man-made objects of complex chemical composition.

Manganese Luminescent Centers of Different Valence in Yttrium Aluminum Borate Crystals.

We present an extensive study of the luminescence characteristics of Mn impurity ions in a YAl3(BO3)4:Mn crystal, in combination with X-ray fluorescence analysis and determination of the valence state of Mn by XANES (X-ray absorption near-edge structure) spectroscopy. The valences of manganese Mn2+(d5) and Mn3+(d4) were determined by the XANES and high-resolution optical spectroscopy methods shown to be complementary. We observe the R1 and R2 luminescence and absorption lines characteristic of the 2E ↔ 4A2 transitions in d3 ions (such as Mn4+ and Cr3+) and show that they arise due to uncontrolled admixture of Cr3+ ions. A broad luminescent band in the green part of the spectrum is attributed to transitions in Mn2+. Narrow zero-phonon infrared luminescence lines near 1060 nm (9400 cm-1) and 760 nm (13,160 cm-1) are associated with spin-forbidden transitions in Mn3+: 1T2 → 3T1 (between excited triplets) and 1T2 → 5E (to the ground state). Spin-allowed 5T2 → 5E Mn3+ transitions show up as a broad band in the orange region of the spectrum. Using the data of optical spectroscopy and Tanabe-Sugano diagrams we estimated the crystal-field parameter Dq and Racah parameter B for Mn3+ in YAB:Mn as Dq = 1785 cm-1 and B = 800 cm-1. Our work can serve as a basis for further study of YAB:Mn for the purposes of luminescent thermometry, as well as other applications.

Total-reflection X-ray fluorescence determination of thorium and uranium in the presence of interfering elements in solid geological objects of natural and technogenic origin

The insufficient spectral resolution of the energy-dispersive total-reflection X-ray fluorescence (TXRF) complicates the U and Th Lα lines using for the quantitative determination of low concentrations of these elements in natural solid samples.

X-ray fluorescence analysis of sulfate-ion in aqueous solutions by dried drop technique using a portable spectrometer

In this paper authors propose the methodology of X-ray fluorescence determination of sulfate-ion in aqueous solutions with preconcentration by dried drop technique using portable energy dispersive spectrometer NITON FXL 959 GOLDD+. The represented measuring procedure has been tested in a wide range of sulfate-ion concentrations (10–4200 mg/l) during exploration the groundwater samples of the Over Jurassic Aquifer complex of the Moscow region and drainage water of the sulfide porphyry-copper mineralization of the Nakhodka ore field (Western Chukotka). Verification of the measuring procedure is based on results of the water investigation by ion chromatography and titration methods.

X-ray Fluorescence Determination of Small Quantities of Hafnium in Nuclear Pure Zirconium-Based Materials

X-ray Fluorescence Determination of Small Quantities of Hafnium in Nuclear Pure Zirconium-Based Materials

Energy dispersive X-ray fluorescence determination of uranium in different uranates using Rh Kα scattered peaks for matrix correction

Determination of uranium in different matrices and compounds is required for compositional analysis and material characterization of uranium based materials. In the present work, we have explored the possibility of utilising Rh Kα scattered peaks: Compton and Rayleigh, for minimizing the effect of matrix and determining uranium in different matrices using Energy Dispersive X-Ray Fluorescence (EDXRF) spectrometry. The method was applied for determination of uranium in presence of Na, Zn, Rb, Bi and Th in solid samples presented in the form of compounds and mixtures. Different calibration plots were made for U in different matrices against the intensity of the scattered peaks. Different procedures of calibration were studied using both uranium Lα and Lβ as analytical lines. Sample specimens were presented in the form of fused bead as well as pressed pellets. The advantage of this method is that there is no need to add any standard in the samples. The analytical results of all the studies showed an average deviation of 3% between the EDXRF determined and the expected uranium concentrations and a RSD (Relative Standard Deviation) of 4% (1 s, n = 3).

Firing Parameters Effect on the Physical and Mechanical Properties of Scheelite Tailings-Containing Ceramic Masses

The firing parameters in ceramic masses incorporated with 0, 5, and 10 wt% of scheelite tailings were investigated. The ceramic masses were characterized by X-ray fluorescence, granulometric, mineralogical analysis, and Atterberg limits determination. The samples were obtained by uniaxial pressing (20 MPa), sintered at different temperatures (800, 900, and 1000 °C), and heating rates (5, 10, 15, and 20 °C∙min−1). Physical and mechanical tests (water absorption, apparent porosity, and flexural strength) and mineralogical tests were accomplished from the sintered samples. Natural aging tests were also carried out to assess carbonation resistance. For this, some samples were kept in an internal environment (inside the laboratory) for 3 months. The results showed a high content of calcium oxide in the scheelite tailings and a reduction in the plasticity index of the ceramic masses with the tailings addition. The best results were observed for the ceramic mass with 5% tailings. The best results were observed regarding the firing parameters for the temperature equal to 1000 °C, increasing the heating rate to 10 °C∙min−1 without compromising the material properties. The samples kept in an internal environment for 3 months showed a loss of physical and mechanical properties. Such behavior probably occurred due to the onset of the carbonation phenomenon.

Rapid X-ray fluorescence analysis of intercalation compounds for molybdenum and cobalt content

Synthesizing and studying the properties of nanomaterials based on layered molybdenum disulfide, often face a need for rapid elemental analysis and prompt return of the material to the customer. Sometimes, nanoparticles of molybdenum disulfide are to be modified with metal compounds to improve the catalytic or magnetic properties of the material. We propose a method for rapid X-ray fluorescence determination of molybdenum and cobalt in the range of 10 – 50% in such compounds using a bulk method without dilution. Analytical signals were measured at the wavelengths of MoKα and CoKα lines using a VRA-30 spectrometer (Carl Zeiss, Germany; X-ray tube with Rh anode). The metal content was calculated using the derived coupling equations. The determination error ranges within ±2.7% (abs.) and 1.4% (abs.) for Mo and Co, respectively. Correctness of the method was confirmed for a batch of synthesized compounds by comparison of the results obtained with the data of XRF analysis using the dilution method traditionally used in the laboratory. The proposed rapid method provides simplification of the procedure and more than 4-fold shortening of analysis in time, the sample being preserved and can be used for further research.

X-ray fluorescence determination of small quantities of hafnium in nuclear pure zirconium materials

An important chemical impurity in the composition of zirconium materials for nuclear power engineering is hafnium, the content of which should not exceed 0.05 and 0.01% for domestic and foreign alloy grades, respectively. Hafnium, being an analogue of zirconium in its chemical properties, is difficult to be analyzed using classical methods of analytical chemistry. Among the physical methods, the X-ray fluorescence method is the most expressive, which is important in conditions of continuous production. The method of X-ray fluorescence for measuring the content of hafnium in zirconium-containing material has been tested on the example of potassium fluorozirconate, a precursor for obtaining alloys. With various combinations of crystal analyzers, detectors, and collimators of the wave-dispersive spectrometer, the ratios of the intensities of the analytical lines of Hf and Zr in the second order of reflection were refined, and the degree of decrease in the fluorescence intensity of those lines was determined. The X-ray fluorescence spectra of hafnium lines in potassium fluorozirconate at the content characteristic of nuclear-pure zirconium are studied. The possibility of recording the intensity of the Hf analytical lines and methods of eliminating the interference from the Zr lines in the second order of reflection are considered. The metrological characteristics are calculated for Hf analytical lines. It is shown that the smallest error and the lowest detection limit (0.001%) is provided when using the HfLβ1 line at certain settings of the wave-dispersive spectrometer, including the X-ray tube operation mode, a combination of a crystal analyzer, a detector and a collimator, as well as the amplitude discriminator settings. The method of accounting for the background is recommended. The proposed method of hafnium determination is applicable to the materials with a constant content of zirconium.

Control of the chemical composition of heat-resistant nickel alloys upon manufacturing products from these alloys using additive technologies

Heat-resistant alloys (superalloys) widely used for manufacturing parts of various components of aircraft engines are complex nickel-based systems which contain apart from alloying (Al, Cr, Co, Ti, Mo, W, etc.) and microalloying additives (B, Mg, REM, etc.) different amounts of the impurities (Mn, Fe, Si, Pb, As, Sn), including gas-forming (O, N, C, S) ones. The use of additive technologies (AT) in manufacturing of complex-shaped parts made of these alloys makes it possible to increase the material utilization coefficient and shorten the technological process. However, the use of AT requires real-time control of the composition of semi-products and finished products at all stages of production. Study of various stages of manufacturing parts from ZhS6K and VZh159 alloys using an AT of selective laser alloying (SLA) is carried out using analytical control systems of the laboratory of the Testing Center (TC) of FSUE «VIAM». A complex of methods for atomic emission, mass spectrometric and X-ray fluorescence determination of different groups of elements was used for the analysis of charge materials, cast bar blanks, metal-powder compositions (MPC) and synthesized parts. The results of analysis of nickel N-1u and chromium Kh99N1 used upon and after smelting of cast billets, as well as analysis of MPC of these alloys carried out by different methods are presented (gas analyzers were used to determine the gas-forming impurities). Monitoring on the chemical composition of materials throughout the process of additive manufacturing ensure their compliance with the regulatory requirements and predict the properties of finished products. The work was carried out within the framework of complex scientific direction 2.1 «Fundamental research» («Strategic directions for the development of materials and technologies for their processing for the period up to 2030»).

A Direct Non-destructive Method for Determination of Sulfur in Ore Samples Using EDXRF Spectrometry.

A method has been developed for direct non-destructive energy dispersive X-ray fluorescence (EDXRF) determination of sulfur in solid uranium ores and intermediates, obtained from the alkaline recovery process for uranium from its ores. The method involves thorough grinding of a few mg of solid powder samples to fine particle size and mixing the fine powder thus obtained with a few drops of 10% collodion solution in amyl acetate to make a paste. A very small amount of this paste was transferred with the help of the pestle tip, spread uniformly in the form of thin slurry on Mylar films, and dried to make very thin sample specimens on thin Mylar film supports. These specimens were presented for EDXRF measurements. A calibration plot was made by plotting the intensity ratios of S Kα and Rayliegh scattered peak of the excitation source (Ge Kα) against sulphur percent in the certified reference materials (CRMs). It was found that the precision obtained using this methodology was within 5% (±1σ) and the deviation of the EDXRF analytical results from the expected values of CRM was within 7%. The developed method was successfully applied for the determination of sulfur in the samples obtained from the different stages of the uranium ore processing using alkaline based leaching method.

X-Ray Fluorescence Determination of Ore Elements in Ferromanganese Formations

Elemental analysis of ferromanganese formations (first of all, the determination of ore elements) is a necessary stage in the development of ore deposits. A technique for X-ray fluorescence quantitative analysis was proposed for the determination of iron, manganese, cobalt, nickel, copper, and zinc in oceanic ferromanganese formations (nodules and crusts). The studies were performed using a S4 Pioneer wavelength-dispersive spectrometer equipped with a LiF (200) crystal and a scintillation detector. In order to plot the calibration curves, sets of certified reference materials such as ferromanganese nodules, cobalt-bearing ferromanganese crusts, and pelagic sediments previously dried at 105°C for 24 h to remove hygroscopic moisture were used. Two sample preparation techniques were compared: pressing of powder samples with the use a boric acid substrate and homogenizing via fusion with lithium tetraborate at a ratio of 1 : 30 in an electric furnace at 1050°C. For each sample preparation technique, spectral overlaps and matrix correction methods (theoretical and empirical) were considered, and optimal calibration curves for determining ore elements were chosen. The accuracy of the X-ray fluorescence technique was assessed via analyzing a reference material FeMn-1 with a certified content of ore elements and a reference ferromanganese nodule sample preliminarily analyzed using a PerkinElmer M403 atomic absorption spectrometer. Both homogenization via fusion and analysis of pressed samples provide quantitative X-ray fluorescence determination of the main ore elements and can be used to assess the industrial significance of oceanic ferromanganese formations.

X-ray fluorescence determination of zinc sulfate in acidic zinc plating electrolyte

Zinc sulfate is the main component in the composition of the acidic zinc plating electrolyte. Deviation in the electrolyte composition from the optimum content leads to destabilization of the electrolysis process and deteriorate the quality of the resulting zinc coating. The proper quality of a zinc coating obtained by galvanic deposition can be ensured only with timely monitoring and adjustment of the electrolyte composition. A technique of X-ray fluorescence determination of zinc (in terms of zinc sulfate) in an acidic zinc plating electrolyte is proposed. The study was carried out using an ARL Quant’X energy dispersive spectrometer (Thermo Fisher Scientific, USA) with a semiconductor silicon-lithium detector. The features of the spectrometer design are presented. The optimal parameters of excitation and detection of zinc radiation were specified when the electrolyte sample was diluted 1:1000. The ZnKα1 line was used as an analytical line. The plotted calibration graph is linear, the correlation coefficient being 0.999234. The results of zinc determination according to the developed method were compared with the data of the reference method of complexometric titration to prove the reliability of the procedure. The results are characterized by good convergence and accuracy. The proposed method of X-ray fluorescence zinc determination in a zinc plating electrolyte equals complexometric titration in the limiting capabilities and even exceeds the latter in terms of the simplicity of sample preparation and rapidity. The developed method of X-ray fluorescence determination of zinc is implemented in analysis of the electrolyte used in the continuous galvanizing unit at «METSERVIS LLC».

An Emerging Frontier: Metal(loid) Soil Pollution Threat Under Global Climate Change.

An Emerging Frontier: Metal(loid) Soil Pollution Threat Under Global Climate Change.

Comparison of sample preparation techniques and matrix effects correction methods for X-ray fluorescence determination of total iron and rock-forming elements in iron ores

The genesis of deposits determines wide variations in the mineral and chemical composition of iron ores. It is necessary to determine the content of not only the main ore element (Fe), but also the main rock-forming elements, especially those that affect the quality of the product obtained from the ore (for example, P and Mn). When determining Fe, Mg, Al, Si, P, Ca, Ti, and Mn in iron ores by wavelength-dispersive X-ray fluorescence analysis, two common sample preparation techniques were compared: pressing powder samples on a boric acid substrate and homogenization of calcined sample by fusion with lithium tetraborate. For each method, the repeatability of the measurement of analytical lines was evaluated, calibration equations were constructed using certified reference materials of iron ores of various types and two methods for matrix effects correction (fundamental parameters and empirical intensities) were compared. Iron ores samples from the Korshunovskoye, Rudnogorskoye and Tatyaninskoye deposits of the Angarsk ore province (north of the Irkutsk region and southeast of the Krasnoyarsk Krai) were analyzed by the certified atomic absorption and spectrophotometric techniques, and the results were compared with those obtained by X-ray fluorescence analysis. For the main ore element (Fe) and some rock-forming elements (Mg, Al, Si, P) determination, the fusion technique provided a smaller error, however, both techniques could be used to determine Ca, Ti, and Mn. The choice of the sample preparation technique for wavelength-dispersive X-ray fluorescence analysis of iron ores should be based on the appropriateness of the financial and labor costs and the necessary accuracy of the analysis. Keywords : wavelength-dispersive X-ray fluorescence analysis, iron ores, rock-forming elements, borate glasses, matrix effects correction DOI: http://dx.doi.org/10.15826/analitika.2020.24.2.005 Victor M. Chubarov 1 , Elena I. Borkhonova 2 , Alena A. Amosova 1 1 Vinogradov Institute of Geochemistry, SB RAS, 1 А Favorsky st., Irkutsk 664033, Russian Federation 2 Irkutsk State University, 1 Karl Marx st., Irkutsk 664003, Russian Federation

X-Ray Fluorescence Analysis in Biology and Medicine

X-ray fluorescence analysis (XRF) is widely used when determining the concentrations of elements in various materials in biological research. Current review considers the achievements related to the features of the XRF method. X-ray fluorescence analysis in most cases is a non-destructive method that has proven its potential for measuring the concentrations of elements with a high atomic number Z in organs and tissues in vivo. The main areas of its application in biology and medicine are content determination of basic and toxic elements in plants, samples of bones, teeth, hairs, nails and tissues of vital organs, body fluids such as blood, serum, plasma, saliva, urine, etc. Usually, these studies are part of applied programs that include environmental and metabolic analyses of the population, including the influence of professional factors. The advantages of XRF are also discussed with regards to biological materials. It is noted that the form of the element in the sample practically does not affect the analysis result. In recent years, several new XRF spectrometers models have been designed, where polycapillary lenses and half lenses are used as collimating systems. This is important in the case of in vivo application of X-ray fluorescence determination of certain elements in bones and tissues. The dynamic development is typical for detectors with thermoelectric cooling. Variants of preparation of biological materials for analysis are discussed (grinding, dry or wet ashing, acid decomposition, use of suspensions in the case of XRF with TIR). The results of evaluating the interelement effects for XRF of materials of plant origin, including herbs, spices, apple leaves, birch and tomato leaves, tea, wheat, rye, rice, oatmeal, flax flour, beans, ground, and instant coffee are presented. Examples of the use of XRF in various types of forensic research are considered: poisoning, counterfeiting of drugs and food brands, dental implants, identification of remains. The review presents examples of the participation of Russian X-ray physicists in solving the problems under consideration. The list of references is 400 papers, mainly including the publications of the last 20 years.

X-ray fluorescence determination of the composition of ash from incineration of organochlorine wastes from direct chlorination of ethylene to 1,2-dichloroethane

X-ray fluorescence determination of the composition of ash from incineration of organochlorine wastes from direct chlorination of ethylene to 1,2-dichloroethane

X-ray fluorescence determination of ore elements in ferromanganese formations

Elemental analysis of ferromanganese formations (first, determination of the ore elements) is a necessary stage in the development of ore deposits. A technique for X-ray fluorescence quantitative determination of iron, manganese, cobalt, nickel, copper and zinc in oceanic ferromanganese formations (nodules and crusts) is proposed. The study was performed on wavelength-dispersive spectrometer S4 Pioneer (Bruker AXS, Germany) with LiF (200) crystal and scintillation detector. To plot the calibration curves, sets of certified reference materials of ferromanganese nodules, cobalt-bearing ferromanganese crusts and pelagic sediments, previously dried for 24 hours at 105°C to remove hygroscopic moisture were used. Two sample preparation techniques were compared: pressing of powder samples on a boric acid substrate and homogenization by fusion with lithium tetraborate in a ratio of 1 : 30 in an electric furnace at 1050 °C. For each sample preparation technique spectral overlaps and matrix correction methods (theoretical and empirical) were considered and optimal calibration curves for determination of ore elements were selected. The accuracy of the X-ray fluorescence technique was assessed in analysis of a certified reference material FeMn-1 and reference ferromanganese nodule sample using atomic absorption spectrometry on an M403 spectrometer (PerkinElmer, USA). Both homogenization by fusion and analysis of pressed samples provide quantitative X-ray fluorescence determination of the main ore elements and can be used to assess the industrial significance of oceanic ferromanganese formations.