No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Combined LA-ICP-MS and SEM-EDX analyses for spatially resolved major, minor and trace element detection in cement clinker phases
Abstract
This study combines 2D element mappings obtained by laser ablation with inductively coupled plasma mass spectrometry (LA-ICP-MS) and energy dispersive X-ray spectrometry (EDX) in the scanning electron microscope (SEM) to analyse the chemical composition of cement clinker phases. It is revealed that this approach enables to determine the major and trace element concentrations in phases like alite, belite and the interstitial phase of real Portland cement clinker. A protocol is shown how to record and subsequently register both datasets as such, that the combined analysis significantly broadens the output of the individual measurements. The low detection limits of LA-ICP-MS delivers trace element concentrations and the high spatial resolution and analytical accuracy of SEM-EDX identifies the clinker phases.
Results show that Ba, K, V, and Rb are preferentially incorporated into belite. This allows to study the influence of minor and trace elements on the stabilisation and reactivity of clinker phases.
... This analysis also resulted in unraveling the qualitative and quantitative characteristics of anti-fouling paints [7]. To determine the chemical compositions and 6 th International Conference on Advances in Civil Engineering (ICACE-2022) 21-23 December 2022 CUET, Chattogram, Bangladesh www.cuet.ac.bd/icace heavy metals presence of cement clinker phases, SEM and EDX approach has been found to be utilized as suggested [8]. Furthermore, the unmodified natural bitumen and poly-phosphoric acid (PPA) modified bitumen are classified through SEM-EDX analysis to compare their efficiency as a pavement binder [9]. ...
In Bangladesh, a huge amount of paint sludge is generated annually as waste materials from the paint industries which is generally incinerated causing environmental degradations. In order to ensure green management of PS and add value to it, alternative uses are needed to be investigated. SEM (Scanning electron microscopy) and EDX (Energy dispersive X-ray) are the key approaches for setting the targets that can effectively be achieved. In this paper, the chemical and morphological characteristics of PS have been carried out using SEM and EDX analyses. From the analyses, it has been found that the particles size of PS ranges between approximately 4000~6000 nm with mostly spherical and circular in shape having a rough texture surface. It poses a crystal appearance at higher magnification. According to the atomic percentage, the order of the elements is O> C> Si> Ca > Al > Fe > Ti > Mg> K. Besides, strong signals for C, O and Si is noticeable. Interestingly, it has been established from SEM and EDX analysis that PS exhibits pozzolonic properties similar to cement and clayey soil on the basis of chemical compositions and morphological properties. Based on that establishment, this study has recommended a number of alternative uses of PS addressing recycling options in a cost effective and environmentally friendly manner.
... Benefiting from the multiple element mappings, component complexity and structural heterogeneity of cementitious materials could be comprehensively revealed by the quantitative EDS images. Generally, the pixel values in quantitative EDS images represent the concentration of elements [30,31]. Given this, the ternary density diagram of major elements such as Ca, Si, and Al or related element ratios can be plotted to analyze the phase assemblage of materials [32]. ...
... This analysis also resulted in unraveling the qualitative and quantitative characteristics of anti-fouling paints [7]. To determine the chemical compositions and heavy metals presence of cement clinker phases, SEM and EDX approach has been found to be utilized as suggested [8]. Furthermore, the unmodified natural bitumen and poly-phosphoric acid (PPA) modified bitumen are classified through SEM-EDX analysis to compare their efficiency as a pavement binder [9]. ...
In Bangladesh, a huge amount of paint sludge is generated annually as waste materials from the paint industries which is generally incinerated causing environmental degradations. In order to ensure green management of PS and add value to it, alternative uses are needed to be investigated. SEM (Scanning electron microscopy) and EDX (Energy dispersive X-ray) are the key approaches for setting the targets that can effectively be achieved. In this paper, the chemical and morphological characteristics of PS have been carried out using SEM and EDX analyses. From the analyses, it has been found that the particles size of PS ranges between approximately 4000~6000 nm with mostly spherical and circular in shape having a rough texture surface. It poses a crystal appearance at higher magnification. According to the atomic percentage, the order of the elements is O> C> Si> Ca > Al > Fe > Ti > Mg> K. Besides, strong signals for C, O and Si is noticeable. Interestingly, it has been established from SEM and EDX analysis that PS exhibits pozzolanic properties similar to cement and clayey soil on the basis of chemical compositions and morphological properties. Based on that establishment, this study has recommended a number of alternative uses of PS addressing recycling options in a cost effective and environmentally friendly manner.
Many methods have been proposed to analyse SEM‐EDS hypermaps of hydrated cementitious materials but none can fit all purposes. In this presentation, we review existing methods for phase identification, stoichiometry quantification, and microstructure quantification in cementitious materials and related materials. We first discuss the unique contribution of SEM‐EDS with respect to the outstanding scientific challenges towards sustainable construction materials. We then compare the SEM‐EDS and image analysis techniques which contribute to answering these challenges. Convergence and divergence in current methods and workflows, and knowledge gaps are highlighted in terms of the specificities of the material (phase assemblage complexity, grain sizes, mixtures, etc.). The discussion is weighted by the required expert knowledge for the sample preparation, microscope operation, and data analysis. We conclude by discussing how microscopy and image analysis integrate into the overall experimental toolkit to investigate and improve cementitious materials.
The hydration of ZnO doped C3S was investigated. Characteristics of the hydrated pastes including mechanical strength, degree of hydration, microstructure, pore structure, bound water and the chemical composition of C-S-H are reported. 0.26 and 0.90 wt% of ZnO in C3S promote the hydration of C3S and the growth of C-S-H needles, resulting in a higher degree of hydration and enhanced compressive strength up to 7 days. Evidence from the XRD quantification and BSE-EDS indicates the change of the chemical composition of the C-S-H from the early age to later ages. BSE-EDS results further revealed the location of the incooperated Zn²⁺ in the C-S-H structure. Correlation of total heat release, MIP porosity and BET total pore volume to compressive strength/DoH were analyzed. Impact of ZnO amount on the hydration enhancement was also discussed.
With the aim of identifying the origin and the manufacturer of a cement, a reliable procedure that provides unambiguous results is needed. Such procedure could resolve practical issues in damage research, liability issues and forensic investigations. A substantial number of attempts for fingerprinting of building materials, including cement, has already been carried out during the last decades. Most of them were based on concentration analysis of the main elements/components. This review provides an overview of provenance studies of cement and the main approaches commonly used. Provenance studies of cement via isotope techniques are also presented and discussed as representatives of the state-of-the-art in the field. Due to the characteristic properties and the occurrence of carefully selected isotope ratios, unique fingerprints of different kinds of materials can be provided by these methods. This property has largely been explored in various scientific fields such as geo- and cosmochemistry, food forensics, archaeology, geochronology, biomedical studies, and climate change processes. However, the potential of isotope techniques in cement and concrete research for provenance studies has barely been investigated. Therefore, the review outlines a suitable approach using isotope ratios, which could lead to reliable provenancing of cementitious materials in the future.
In almost all applications of concrete components, both the transport of substances such as chlorides, sulphates, acids, CO2, etc. through the pore structure into the concrete and the resulting local chemical and physical processes have a negative effect on the lifetime of the structure. Most data are actually obtained from layer-by-layer mechanical sampling of, for instance, bore dust, followed by chemical analysis. Several groups have previously demonstrated the enormous potential of LA-ICP-MS for monitoring these multi element processes both qualitatively and quantitatively and with high spatial resolution. However, there has been no fundamental investigation of laser-material interaction, aerosol particle formation, fractionation analysis or the effect of cement-specific parameters such as the water to cement (w/c) ratio on signal intensity. This paper presents the ablation mechanisms of a frequently used 213 nm quintupled Nd:YAG ns laser operating on the HCP (hardened cement paste) multi-phase system in comparison with amorphous and well-characterized NIST 612 glass. It includes energy-signal considerations, crater evaluations after multiple shots using different energy densities and aerosol structures captured on filters. The investigation determined a linear energy to signal behavior in a range of 2–6 J/cm2, while the ablation mechanism is different to common mechanisms obtained for glass or brass. The aerosol captured on the filter material displays cotton-like structures as well as defined spherical particles, which is comparable to observations made with NIST glass aerosols.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) mapping is a rapidly expanding field in the geosciences because of the wealth of spatial information it provides on the petrogenesis of igneous, metamorphic and sedimentary rocks and ore mineral formation. The technique has also opened many new applications in forensics, archaeology and the imaging of trace metals in biological tissues. Instrumentation advances in both LA and ICP-MS systems now permit precise isotopic analysis with laser spot sizes of <10 μm and sub-ppm detections limits. In particular LA-quadrupole (Q)-ICP-MS systems facilitate mapping of large numbers of elements across nearly the entire mass range of the periodic table. A range of key applications in petrogenesis studies and in the fields of environmental and biological sciences is reviewed. Furthermore, technical considerations including a practical guide for setting up LA-ICP-MS multi-element mapping experiments and the latest innovations in dedicated data reduction and image processing packages for the visualization, interrogation and extraction of quantitative data from LA-ICP-MS maps are discussed, with particular emphasis placed on quadrupole systems. A key issue is imaging artefacts (spectral skew) caused by interaction between the laser repetition rate and the total sweep cycle time, particularly when coupling a sequential Q-ICP-MS analyser to modern low dispersion (fast-washout) LA cells. Running at high repetition rates is recommended for low-dispersion cells as it enables faster scanning while minimizing temporal variations in signal intensity caused by pulsing of the laser. Advances in LA-ICP-MS instrumentation and methodologies (data processing, visualization and extraction) have enabled simultaneous acquisition of compositional and U-Pb age information at high-spatial resolution which has great potential in geochronological studies. Formation histories of complex polyphase accessory minerals such as zircon, titanite or monazite, where discrete age domains are often linked with specific rock-forming processes and their physical conditions (i.e. U-Pb petrochronology), are now directly accessible. Moreover, fine-scale processes affecting the U-Pb systematics of accessory minerals can be constrained when LA-ICP-MS mapping is combined with other textural (e.g. CL or Raman) imaging techniques. U-Pb analysis of materials with variable initial Pb concentrations and/or heterogeneous genetic origin such as carbonates also benefit from such a mapping approach as areas with sufficient spread in ²³⁸U/²⁰⁴Pb ratio (μ) can be targeted, while simultaneous imaging of diagnostic trace elements allows identification and exclusion of zones affected by alteration or detrital contamination. The quasi-simultaneous detection offered by LA-time-of-flight (TOF)-ICP-MS allows rapid multi-element analysis of very fast transient signals (i.e. laser ablation imaging in low dispersion laser ablation cells). The approach is ideally suited to 2D and 3D imaging of biological and geological materials and will likely replace LA-Q-ICP-MS for such applications once more routinely available.
Production of low-energy cements would result in energy saving and lower CO2 emissions related to reduced consumption of fuel and high-grade limestone as a raw material. Belite rich clinker, made more reactive by doping with combination of S and Li, could possibly be one of the low-energy alternatives for Portland cement clinker. Paper describes the preparation of doped belite and deals with its early hydration and reactivity. Belite rich clinkers were prepared in laboratory in high-temperature solid state synthesis. Pure substances were used for the preparation of raw meal and clinker. Early hydration heat flow development of cement pastes was monitored by isothermal calorimetry, changes in phase composition by “in situ” X-ray diffraction and TGA/DTA and microstructure by SEM-SE. Heat flow exotherms were correlated with quantified phase composition at given time. Intensity and position of main exothermic peak related to hydration of C3S is changing with increasing Li content. Doping of the C2S by the S or the combination of S and Li significantly increases the reactivity of the C2S-rich cement. The formation of C–S–H products is a continuous process that depends mainly on C3S during first 6 h and then is supported by slow reaction of β-C2S. The reactivity of C2S is affected by the timing of the hydration of other clinker phases. Two generations of portlandite formation detectable as a double endotherm on TGA/DTA can be attributed to hydration of C3S and β-C2S.
https://www.research-collection.ethz.ch/handle/20.500.11850/301843
Laser ablation inductively coupled plasma time‐of‐flight mass spectrometry (LA‐ICP‐ToF‐MS) was used to generate quantitative elemental images of a mineralogically and texturally complex fault rock of the Northern Apennines of Italy (Zuccale Fault, eastern Island of Elba). Using LA‐ICP‐ToF‐MS combined with a low‐dispersion LA cell, we were able to generate large format (4 mm × 2 mm), high‐resolution (5 μm), high dynamic range (1–10⁶ μg g⁻¹), and quantitative multi‐elemental two‐dimensional compositional maps within a data acquisition time of a few hours. To quantify element mass fractions across the heterogeneous sample of the Zuccale Fault, we used a 100% species‐mass normalisation approach that took into account different mineral phases across the specimen. To assign mineral phase directly from LA‐ICP‐ToF‐MS data, we exploited the segregation of sulfur and calcium between distinct phases to threshold element images and develop mineral‐phase‐specific masks. Moreover, we demonstrate agreement between elemental mass fractions determined by LA‐ICP‐ToF‐MS imaging with 100% normalisation quantification and conventional LA‐ICP‐MS analysis with internal standard element‐based quantification. Finally, we discuss how this elemental imaging provides unique insights into the genesis of the Zuccale Fault.
This article is protected by copyright. All rights reserved.
The main conclusions of an analysis of low-CO2, eco-efficient cement-based materials, carried out by a multi-stakeholder working group initiated by the United Nations Environment Program Sustainable Building and Climate Initiative (UNEP-SBCI) are presented, based on the white papers published in this special issue. We believe that Portland-based cement approaches will dominate in the near future due to economies of scale, levels of process optimisation, availability of raw materials and market confidence. Two product-based approaches can deliver substantial additional reductions in their global CO2 emissions, reducing the need for costly investment in carbon capture and storage (CCS) over the next 20–30 years: 1. Increased use of low-CO2 supplements (SCMs) as partial replacements for Portland cement clinker.2. More efficient use of Portland cement clinker in mortars and concretes.However, other emerging technologies could also play an important role in emissions mitigation in the longer term, and thus merit further investigation.
LA-ICP-MS and LA-MC-ICP-MS have been the techniques of choice for achieving accurate and precise element content and isotopic ratio, the state-of-the-art technique combines the advantages of low detection limits with high spatial resolution, however, the analysis accuracy and precision are restricted by many factors, such as sensitivity drift, elemental/isotopic fractionation, matrix effects, interferences and the lack of sufficiently matrix-matched reference materials. Thus, rigorous and suitable calibration and correction methods are needed to obtain quantitative data. This review systematically summarized and evaluated the interference correction, quantitative calculation and sensitivity correction strategies in order to provide the analysts with suitable calibration and correction strategies according to the sample types and the analyzed elements. The functions and features of data reduction software ICPMSDataCal were also outlined, which can provide real-time and on-line data reduction of element content and isotopic ratios analyzed by LA-ICP-MS and LA-MC-ICP-MS.
X-ray powder diffraction (XRD) has been used for several decades to identify and measure the mass fractions of various crystalline phases in portland cement. More recently, a combination of scanning electron microscopy with X-ray microanalysis (SEM/XMA) and image processing has been shown to enable the quantitative characterization of microstructural features in these materials. Each technique can furnish some information that is not accessible from the other. For example, SEM/XMA can identify the microstructural location and morphology of calcium sulfate minerals, while only XRD can determine the relative abundance of the different forms of calcium sulfate, such as gypsum (CaSO4 • 2H2O), bassanite (CaSO4 • 1/2 H2O), and anhydrite (CaSO4). This document describes how XRD and SEM/XMA can be used together to establish and validate the portland cement phase composition and microstructure. Particular emphasis is laid on step-by-step procedures and best practices for XRD specimen preparation, data collection, and intepretation. Similar detail has been given recently for SEM/XMA [Stutzman et al., NIST Tech Note 1877, U.S. Department of Commerce, April 2015]. The methods are demonstrated for three portland cement powders, through which apparent discrepancies between the results of the two methods are identified and procedures are described for resolving the discrepancies and quantifying uncertainty.
An accurate and routinely available method for stoichiometric analysis of thin films is a desideratum
of modern materials science where a material’s properties depend sensitively on elemental
composition. We thoroughly investigated femtosecond laser ablation-inductively coupled plasmamass
spectrometry (fs-LA-ICP-MS) as an analytical technique for determination of the stoichiometry
of thin films down to the nanometer scale. The use of femtosecond laser ablation allows for precise
removal of material with high spatial and depth resolution that can be coupled to an ICP-MS to
obtain elemental and isotopic information. We used molecular beam epitaxy-grown thin films of
LaPd(x)Sb2 and T′-La2CuO4 to demonstrate the capacity of fs-LA-ICP-MS for stoichiometric analysis
and the spatial and depth resolution of the technique. Here we demonstrate that the stoichiometric
information of thin films with a thickness of ~10 nm or lower can be determined. Furthermore, our
results indicate that fs-LA-ICP-MS provides precise information on the thin film-substrate interface
and is able to detect the interdiffusion of cations.
Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is a widely accepted method for direct sampling of solid materials for trace elemental analysis. The number of reported applications is high and the application range is broad; besides geochemistry, LA-ICP-MS is mostly used in environmental chemistry and the life sciences. This review focuses on the application of LA-ICP-MS for quantification of trace elements in environmental, biological, and medical samples. The fundamental problems of LA-ICP-MS, such as sample-dependent ablation behavior and elemental fractionation, can be even more pronounced in environmental and life science applications as a result of the large variety of sample types and conditions. Besides variations in composition, the range of available sample states is highly diverse, including powders (e.g., soil samples, fly ash), hard tissues (e.g., bones, teeth), soft tissues (e.g., plants, tissue thin-cuts), or liquid samples (e.g., whole blood). Within this article, quantification approaches that have been proposed in the past are critically discussed and compared regarding the results obtained in the applications described. Although a large variety of sample types is discussed within this article, the quantification approaches used are similar for many analytical questions and have only been adapted to the specific questions. Nevertheless, none of them has proven to be a universally applicable method.
Este artigo apresenta dados composicionais de amostras de clínquer Portland produzido com matérias-primas e combustíveis não convencionais, em especial no que diz respeito à distribuição de elementos menores e traços. Foram amostrados clínqueres produzidos com três misturas diferentes de combustíveis, enquanto os demais parâmetros foram mantidos constantes. Os combustíveis apresentam características químicas típicas, como o teor elevado de enxofre no coque de petróleo e o alto teor de zinco no combustível derivado de pneus. O uso de carbonatito como matéria-prima se reflete nos teores elevados de estrôncio e fósforo. Dados de microssonda eletrônica foram usados para determinar a ocupação de sítios estruturais de C3S e C2S, e para modelar a distribuição de elementos traços entre as fases do clínquer. O fósforo ocorre em proporções similares em C3S e C2S; se considerarmos sua abundância modal, o C3S é o principal reservatório de fósforo no clínquer. O enxofre é preferencialmente concentrado em C2S em comparação com C3S. O estrôncio substitui Ca2+ principalmente em C2S e em fases não-silicáticas, em comparação com C3S.
Research Institute of Building Materials, Brno, Czech Republic Dicalcium silicate (Ca 2SiO 4 or C 2S) containing foreign ions occurs as a component of Portland cement clinker and is called belite. Belite has a lower hydraulic activity than alite, which is the main component of Portland cement clinker. Belite can be prepared at lower expenditure and its hydraulic activation can have important impact on the economy and sustainability of the cement industry. This research focused on the activation of C 2S by incorporation of SO 3 into its crystal structure. This paper describes experiments with pure chemicals that characterise substitution of SiO 2 by SO 3 and its influence on the hydraulic activation of C 2S. It was confirmed that sulfur stabilises the monoclinic modification β-C 2S. The maximum content of SO 3 in C 2S under common laboratory burning conditions was approximately 4.4 wt%. The hydraulic activity of prepared β-C 2S doped with SO 3 was up to three times higher than in the reference non-activated β-C 2S.
Electron-excited X-ray microanalysis performed in the scanning electron microscope with energy-dispersive X-ray spectrometry (EDS) is a core technique for characterization of the microstructure of materials. The recent advances in EDS performance with the silicon drift detector (SDD) enable accuracy and precision equivalent to that of the high spectral resolution wavelength-dispersive spectrometer employed on the electron probe microanalyzer platform. SDD-EDS throughput, resolution, and stability provide practical operating conditions for measurement of high-count spectra that form the basis for peak fitting procedures that recover the characteristic peak intensities even for elemental combination where severe peak overlaps occur, such PbS, MoS2, BaTiO3, SrWO4, and WSi2. Accurate analyses are also demonstrated for interferences involving large concentration ratios: a major constituent on a minor constituent (Ba at 0.4299 mass fraction on Ti at 0.0180) and a major constituent on a trace constituent (Ba at 0.2194 on Ce at 0.00407; Si at 0.1145 on Ta at 0.0041). Accurate analyses of low atomic number elements, C, N, O, and F, are demonstrated. Measurement of trace constituents with limits of detection below 0.001 mass fraction (1000 ppm) is possible within a practical measurement time of 500 s.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has numerous applications as an almost non-destructive analytical technique of high spatial resolution and sensitivity. It can be used to determine major, minor, and trace elements as well as isotope-ratios in various types of solid materials. For solid sample quantitative analysis, the main analytical problem is the calibration step: evaluation of the function (equation) that correlate the signal to the concentration of analyte in the sample. Additional problems result from non-stoichiometric effects during sampling, transport of ablated aerosol, vaporization, atomization, and ionization in the plasma. The effects, called elemental fractionation, are mainly sample matrix dependent and thus suggests that standards used for calibration should accurately match the sample matrix. Preparation of such standards is a difficult and time-consuming process, so since the beginning of LA-ICP-MS applications for quantification of solid sample composition, different approaches are been created to solve the problem, primarily complete matrix matching. Because the calibration of LA-ICP-MS is a key factor for its quantification capabilities, previous achievements are presented from a selection of reviewed papers. This review summarizes some recent calibration approaches and related standard preparation techniques for the analysis of various solid materials by LA-ICP-MS. Selected papers concern the application of reference glasses; solution based standards; synthetic standards based on the main sample matrix component or powdered matrix certified reference materials; matrix-matched standards based on spiked sample material; and non-matrix-matched standards for calibration. Standard dilution methods and signal normalization protocols used in order to improve precision are considered. Key words: laser ablation; inductively coupled plasma mass spectrometry; calibration
The influence of ablation cell geometry (Frames single- and HelEx two-volume cells) and laser wavelength (198 and 266 nm) on aerosols produced by femtosecond laser ablation (fs-LA) were evaluated. Morphologies, iron mass distribution (IMD) and 56Fe/54Fe ratios of particles generated from magnetite, pyrite, haematite and siderite were studied. Two morphologies were identified: spherules (10–200 nm) and agglomerates (5–10 nm). Similarity in IMD and ablation rate at 198 and 266 nm indicates similar ablation mechanisms. 56Fe/54Fe ratios increased with aerodynamic particle size as a result of kinetic fractionation during laser plasma plume expansion, cooling and aerosol condensation. The HelEx cell produces smaller particles with a larger range of 56Fe/54Fe ratios (1.85‰) than particles from the Frames cell (1.16‰) but the bulk aerosol matches the bulk substrate for both cells, demonstrating stoichiometric fs-LA sampling. IMD differences are the result of faster wash out of the HelEx cell allowing less time for agglomeration of small, low-δ 56Fe particles with larger, high-δ 56Fe particles in the cell. Even with a shorter ablation time, half the total Fe ion intensity, and half the ablation volume, the HelEx cell produced Fe isotope determinations for magnetite that were as precise as the Frames cell, even when the latter included an aerosol-homogenising mixing chamber. The HelEx cell delivered a more constant stream of small particles to the ICP, producing a more stable Fe ion signal (0.7% vs. 1.5% RSE for 56Fe in a forty-cycle single analysis), constant instrumental mass bias and thus a more precise measurement.This article is protected by copyright. All rights reserved.
Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), which is a rapidly developing analytical technique for the analyses of trace elements and isotopes, plays an important role in advancing the study of Earth science, especially with respect to micro-geochemistry. This article reviews the application of LA-ICP-MS in the elemental analysis of solid geological samples. Although LA-ICP-MS has been widely used in the spatial resolution analysis of element compositions and rapid bulk analysis of whole-rock and soil samples, the analysis accuracy is restricted by numerous factors, including the instrumental conditions, the elemental fractionation and matrix effects, the lack of sufficient matrix-matched reference materials, and the strategies for quantitative calibration and sensitivity drift correction. According to the type of samples and the analyte elements, the analysis accuracy can be improved through the optimization of instrument conditions and the adoption of suitable correction strategies and reference materials.
The qualitative identification to determine the origin (i.e. manufacturing factory) of Spanish clinkers is described. The classification of clinkers produced in different factories can be based on their trace element content. Approximately fifteen clinker sorts are analysed, collected from 11 Spanish cement factories to determine their Mg, Sr, Ba, Mn, Ti, Zr, Zn and V content. An expert system formulated by a binary decision tree is designed based on the collected data. The performance of the obtained classifier was measured by ten-fold cross validation. The
results show that the proposed method is useful to identijy an easy-to-use expert system that is able to determine the origin of the clinker based on its trace element content
The influence of phosphorous pentoxide (P2O5) on the phase composition and formation of Portland clinker was studied in laboratory conditions. Phosphorous pentoxide in the form of calcium phosphate was added to common cement-making raw meal in graded quantities up to 5 wt.%. The raw meal properties were studied by thermal analysis. The development of clinker formation by burning for periods ranging from 20 s to 30 min in a special semi-automatic oven with a manipulator was followed using light optical microscopy. The phase composition of clinkers burnt to equilibrium was quantified by the optical point counting method. The entry of P2O5 into clinker minerals was determined by electron microprobe analyses. The laboratory tests show that at 0.7 wt.% of P2O5 in the clinker the alite (Ca3SiO5) content decreases and belite (Ca2SiO4) content increases. At a P2O5 content of 4.5 wt.% alite formation was totally blocked and the resulting clinker contained free lime in equilibrium with belite.
Elemental fractionation in femtosecond laser ablation is studied by ICP-MS by applying successive single laser shots to binary metallic and semiconductor samples as well as to multi-component glasses. Fractionation can be observed in the first laser shots in particular if the laser fluence is near the ablation threshold of the sample. However, the element ratio in the laser-sampled masses changes from shot to shot until it reaches an asymptotic fluence-independent value representing stoichiometric sampling. The asymptotic stoichiometric ratios can be obtained with fewer shots if higher laser fluences are applied. It is shown by electron probe X-ray analysis that different elemental ablation probabilities modify the element compositions in the surface layers of the laser craters until equilibrium conditions are obtained. These conditions can be reached by applying many shots of low laser fluence or with one high-fluence laser shot only. The experimental data reveal that in most cases the elemental ablation probability can be correlated with the respective ionization energies of the elements, i.e., the elements with lower first ionization energy have higher ablation probability. No or only very weak fractionation was observed when elements with nearly the same ionization energies were sampled.
Use of alternative fuels in cement production has three important perspectives: dimension of the industry, its environmental impacts, and the fitness of the process for the purpose of waste management. The global production volume of cement is >4 billion tonnes for the last five years, the energy consumption was about 11 EJ in 2016, and the annual CO2 emission was 2.2 Gt. External to the industry, there is a huge problem of managing waste, which was at a level of about 2 billion tonnes in 2016. All these parameters will enormously aggravate by 2050, affecting sustainability and climate. Co-processing of certain combustible waste in cement kilns has evolved as an important tool for addressing the problems. The paper primarily deals with the sources and types of waste on one hand and effects on clinker process and properties on the other.
There are several avenues and schools of thought how to generate good 2D LA-ICP-MS (multi)elemental maps. Especially with the recent advent of "fast" LA cells and the use of simultaneous ICP-TOFMS detectors, instead of the commonly used sequential ICP-QMS detectors, the playing field has changed radically. Generally, data are generated in line scanning mode by pulsed laser ablation of the surface and ICP-MS sampling (signal integration) of one or more pulses. In the imaging process we may encounter all kind of imaging artifacts such as blur, smear, aliasing and noise that may deteriorate the image quality. In this paper deeper insights into the selection of optimal conditions for fast and high-quality 2D LA-ICP-MS (multi)elemental mapping are given to circumvent or minimize these artifacts based on a modeling approach.
The ability of Nirex Reference Vault Backfill (NRVB), a cement backfill material, to capture carbon dioxide from Intermediate Level Radioactive waste packages after repository backfilling, has been assessed. Large-scale trials assessed the physical and chemical reaction of carbon dioxide with the hardened backfill grout. A carbonation front, radial in nature, was observed extending into the grout and three distinct regions were identified in the hardened grouts. A carbonated region, a carbonation front, and a partially carbonated zone were discerned. Potassium, and to a lesser extent sodium, were concentrated in the carbonated region just behind of the main reaction front. The area just ahead of the carbonation front was enriched in both sulphur and aluminium, while sulphur was found to be depleted from the carbonated material behind the main reaction front. Within the main carbonated region, virtually all of the hydrated cement phases were found to be carbonated, and carbonation extended throughout the grout, even within material indicated by phenolphthalein solution to be uncarbonated. Importantly, carbonation was observed to impact both the mineral assemblage and porosity of the cement backfill; it is therefore important to understand these characteristics in terms of the long term evolution of NRVB and its groundwater buffering safety function within the geological disposal facility near-field.
The visualization of elemental distributions in biological tissues can provide valuable information about biological and medical correlations and there is an increasing demand for spatially resolved and quantitative information. The trend for elemental bioimaging goes to ultrafast and high (spatial) resolution analysis. The use of an inductively coupled plasma mass spectrometry (ICPMS) instrument equipped with a time of flight (ToF) mass analyzer offers the great advantage for this application because of quasi simultaneous analysis of the entire elemental mass spectrum. It offers high isotope ratio measurement precision and thus the suitability for isotope dilution analysis (IDA). In this work, rat kidney samples from Cisplatin (Pt based anti-cancer drug) perfusion experiments were investigated using an ICP-ToFMS analyzer and the results were discussed regarding the calibration approaches, the suitability for isotope ratio measurement and the quasi simultaneous detection of all elements. Due to the speed of the ToF detector and the use of the aerosol rapid introduction system (ARIS), an ultrafast bioimaging approach was used that allowed analysis of a 70 mm² area in just 5 h. On top of that, plasma fluctuations and thus signal deviations induced by large droplets reaching the plasma could be traced back and explained thanks to the multi-elemental and simultaneous detection.
Understanding the dopant behavior in cement clinker has been an important issue due to the increasing use of alternative fuels and secondary raw materials for cement manufacturing following the rising demand for reduction of CO2 emissions and energy consumption. In this work, state-of-the-art ab initio calculations have been employed to systematically investigate manganese (Mn) doping mechanism in four dominant clinker phases. Corresponding experimental studies are incorporated to verify simulated results. A conspicuous preference of Mn for occupying the Fe site in ferrite is found based on formation energy analyses, which is in accord with our experiments and vast literatures. More in-depth analyses indicate the Mn doping mechanism follows the “electronic structure matching” principle, which influences the stability of doped structures by inducing localized coordination distortions. The work provides a fundamental perspective to investigate doped clinker, which facilitates the searching for other doping species, thereby designing steerable doping-enhanced cement.
It was Castaing who many years ago lamented “First 1 realized that in massive samples which concerned the metallurgists i would have to give up the splendid resolving power that I had cheerfully envisaged, as 1 became aware of the terrific path that my electrons would perform haphazardly in the sample before agreeing to stop. I had to limit my ambitions to analyzing volumes of a few cubic micrometers. This was a big disappointment. ..”. In the early days most instruments for imaging and microanalysis of bulk samples were restricted to operating only at relatively high beam energies (∼30kV) and for many (and perhaps too many) years this became the accepted operating procedure. However, we now know there are substantial advantages (pros) in using lower, and in some cases much lower, voltages; but also some significant limitations (cons). So what is possible?
Portland-cement based concrete samples were incubated for 28 days (short-term) in microbially derived H2SO4 (pH 1.3–2.4) and chemically generated H2SO4 (pH 1.0 and 2.0) to investigate potential differences between the two acid attacks. Additionally, long-term biogenic experiments were performed over two, three and six months to evaluate the corrosion behavior over time. Corrosion was evaluated by visual, physical and chemical parameters, including laser ablation inductively coupled plasma mass spectrometry. The 28-day experiments revealed a pH-dependent degree of damage. No obvious differences between biologically and chemically generated H2SO4 were observed based on similar elemental distributions in the corrosion layers. For the long-term experiments, the corrosion primarily depended on the amount of H2SO4 produced by A. thiooxidans which varied within different set-ups. No linear relation between the degradation and incubation periods was observed. In all set-ups, gypsum was the main corrosion product and no microbial growth was observed within the corrosion layer.
en It is shown that accurate x‐ray microanalysis of frozen‐hydrated and dry organic compounds, such as model biological samples, is possible with a silicon drift detector in combination with XPP (exponential model of Pouchou and Pichoir matrix correction) software using ‘remote standards’. This type of analysis is also referred to as ‘standardless analysis’. Analyses from selected areas or elemental images (maps) were identical. Improvements in x‐ray microanalytical hardware and software, together with developments in cryotechniques, have made the quantitative analysis of cryoplaned frozen‐hydrated biological samples in the scanning electron microscope a much simpler procedure. The increased effectiveness of pulse pile‐up rejection renders the analysis of Na, with ultrathin window detectors, in the presence of very high concentrations of O, from ice, more accurate. The accurate analysis of Ca (2 mmol kg⁻¹) in the presence of high concentrations of K is possible. Careful sublimation of surface frost from frozen‐hydrated samples resulted in a small increase in analysed elemental concentrations. A more prolonged sublimation from the same resurfaced sample and other similar samples resulted in higher element concentrations.
Lay description
fr X‐ray microanalysis of biological samples is used to provide information on the elemental composition of cells and spaces such as blood vessels. This is essential for understanding how cells and organs work. To preserve samples in a life‐like condition they are held in the frozen state for analysis. This paper deals with aspects of preparation and assessing the suitability of the mathematical methods used to give quantitative data. The latter have been developed for analysing nonliving, inorganic, materials not for analysing biological samples. It is shown, using model biological samples of known composition, that the procedures give accurate information and can be used with confidence to analyse biological samples.
The aim of this study was to investigate the relative role of chemically and microbially derived sulfuric acid (H2SO4) corrosion on hardened cement paste representing a concrete binder. Cement stone disks were exposed to chemical H2SO4 (pH 1.0 and 2.0) and biological H2SO4 (pH 1.5–2.1). After 28 days, the degree of damage was evaluated by common visual-physical parameters and laser ablation-ICP-MS as a novel evaluation tool to assess changes in elemental distributions. The results revealed a pH-dependent degree of damage. The 4 mm thick disk at pH 1.0 was completely corroded. For the disks exposed to biogenic and chemical H2SO4 at pH 2.0 an intact core remained with a similar thickness of the corrosion layer (1.8–2.0 mm) and sulfuric acid penetration depth (1.1–1.3 mm). Since the elemental distribution was similar in the corroded layer independent of applying biological or chemical H2SO4, no obvious differences between the two acid attacks were revealed.
Inspection of the chloride content in concrete samples is an important factor for determination and planning of maintenance measures. The standard method given by European legislative for chloride determination is the titrimetric Volhard method. However, it requires significant experimental effort, and knowledge about the cement content in the concrete is required. In this work, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is proposed as an alternative method to the commonly used wet-chemical approach. LA-ICP-MS allows analysis of drilled core concrete samples with increased depth resolution, minimal workload for sample preparation, and fast analysis time. Furthermore, exploiting the multi-elemental capabilities of ICP-MS, an in-depth analysis of the sample composition, allowing a differentiation between cement phase and aggregates is feasible. Using this information, selective determination of chloride in the cement phase becomes possible, which helps to increase the reliability of the determined chloride concentrations.
Over the years technology in the cement industry has been further developed with a growing focus on sustainable, cost- and energy-efficient production. While significant steps may not seem visible on a year to year basis, the medium-term view shows notable progress. The trend of increasing the capacity of cement kilns has slowed down in recent years — maximum clinker output still lies between 12,000 and 13,000 tpd. Burning and cooling technologies have progressed, especially with respect to burners specifically designed for the co-incineration of high levels of alternative fuels. Taking into account all process-integrated measures, thermal process efficiency reaches values above 80% of the theoretical maximum. The grinding of raw materials and cement has been in the focus of better energy utilisation, but product quality is also of the highest importance. In terms of sustainable production, NOx abatement and CO2 capture and its reuse remain in the focus of extensive research.
This paper aims to review the progress in cement clinker chemistry since the last International Conference on the Chemistry of Cement in 2011. Although Portland cement clinker is still, by far, the most important compound of modern cements we show that there is a strong development of alternatives. This is mainly due to the emission of carbon dioxide during the calcination of calcium carbonate as raw material whose reduction is the goal of international activity due to anthropologically caused climate change. Furthermore, it is an objective to use both more raw materials that are located close to the concrete plants and alternative fuels. Developments in the field of cement clinker chemistry show a potential for alternatives. Thereby we discuss both old and new ideas. But it has been shown that the substitution of Portland cement clinker has to consider not only reduction in CO2 emission during fabrication: For practical solutions the performance in both in terms of strength development and durability has to be adequate compared to the ordinary Portland cement clinker.
Chloride represents a major risk for reinforced concrete structures because at a certain concentration, it can promote depassivation of the steel bars and initiate corrosion. Therefore it is important to be able to measure the chloride content in concrete. In this paper the application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for the study of chlorides in concrete is proposed. This scanning technique enables quick multi-element profiling, directly at the sample without the need for further preparation, within a range of sub-millimetre (meso-scale) resolution and with low limits of detection. Optimization of the operating conditions was performed in pressed concrete powder pellets. Linearity of the calibration was verified and limits of detection below 0.05 wt% of cement were determined. Chlorine, calcium and iron distributions were studied in cement based materials of increasing heterogeneity (paste, mortar and concrete). This technique is furthermore proposed for the study of the chloride induced corrosion process, by following element distributions along the concrete-steel interface at the time of depassivation.
The results about the influence of Cr, Ni, and Zn on the properties of the pure clinker phases C3S [1] C3A and C4AF are reported in two papers. Part II deals with the clinker phases C3A and C4AF. Samples were prepared with dosages of 0.02, 0.1, 0.5, 2.5, and 5.0 wt.% of Cr, Ni, and Zn (in form of their oxides). The doped C3A and C4AF were investigated for the content of free lime, the rate of evaporation of the metals, and by X-ray powder diffraction. The rate of heat liberation was studied by differential scanning calorimetry. The hydration products were investigated by X-ray powder diffraction and scanning electron microscopy combined with an energy-disperse X-ray spectrometer. All in all the heavy metals only have an influence on the reactivity of the C3A and C4AF when the dosage is much higher than in ordinary portland cement.
A model is proposed that identifies Kelvin–Helmholtz instabilities as one of the major sources of large particle production in LA-ICP-MS measurements under optimized conditions. The model describes the impact transfer from the expanding plasma to the liquid melt layer and the subsequent generation of droplets of variable sizes. The generated droplet spectrum is found to be dependent on melt layer thickness, surrounding atmosphere and laser parameters. The calculation of the melt layer thickness is based on a solution of the three dimensional heat conduction equation with moving interface boundaries that was previously introduced. Beside the calculation of the particle distribution function, the fluence dependency of the distribution and the particle size dependent chemical composition is explained by the model. Preliminary experiments with brass samples confirm the model calculations. The proposed model allows identifying optimal conditions for laser sampling in the regime which is typically used in LA-ICP-MS.
In this paper analytical evidence on crystal structure and hydration behaviour of C3A solid solutions with MgO, SiO2, Fe2O3, Na2O and K2O is given. Samples were prepared using an innovative sol-gel process as precursor, examined by X-ray powder diffraction, infra-red spectroscopy and the crystal structure was refined by the Rietveld method. A significant shift of lattice parameters was found for C3A solid solutions with SiO2, Fe2O3 or Na2O but only minor changes were detected for K2O. The hydration of C3A solid solutions in the absence of CaSO4 was accelerated for samples doped with SiO2 or K2O and it was retarded in the case of MgO, Fe2O3 or Na2O. The hydration in the presence of CaSO4 was accelerated when C3A was doped with K2O or Na2O, whereas Fe2O3 strongly retarded the hydration. The doping with SiO2 nearly had no influence on the hydration, the effect of MgO was not straight forward.
The state of the art of quantitative analysis of phases in Portland cement clinkers lies in the selection of the optimal experimental conditions. The important parameters, such as acceleration potential, probe size, sample preparation and software handling are discussed.
The possibility of quantitative elemental analysis of solids by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) has been investigated. The solids were mixed with binder material in a ratio of 1:10 and pressed into a pellet in order to obtain a similar matrix composition (matrix matching), and further so that an internal standard could be added. The binder material used was a 1:1 mixture of graphite and cellulose, the latter being impregnated with an aqueous palladium standard solution.The method was applied to various types of reference materials, including organic materials (leaves and grass), coal, fly ash and several geological materials. Though with the internal standard a precision of 3–6% relative could be obtained, matrix matching was not completely satisfactory. For all the reference materials, results were generally within a factor of 5 of the reference values. This proved to be independent of the mode of the laser (free-running or Q-switched), the elements studied (over 50) and the sample materials investigated.The detection limits obtained ranged from levels for the lower mass elements to 1–100 for the higher mass elements. However, the experimental set-up was subject to large memory effects. Detection limits estimated to be ultimately attainable if the memory effects can be overcome are a factor of 10–100 better.
As laser ablation becomes more ubiquitous for direct solid sampling with inductively coupled plasma mass spectrometry (ICP-MS), the need to understand and mitigate fractionation (non-stoichiometric generation of vapor species) becomes critical. The influence of laser-beam wavelength on fractionation is not well established; in general, it is believed that fractionation is reduced as the wavelength becomes shorter. This manuscript presents an investigation of fractionation during ablation of NIST glasses and calcite using three UV wavelengths (157 nm, 213 nm and 266 nm). Fractionation can be observed for all wavelengths, depending in each case on the laser-beam irradiance and the number of laser pulses at each sample-surface location. The transparency of the sample influences the amount of sample ablated (removed) at each wavelength, and the extent of fractionation. Pb/Ca and Pb/U ratios are used as examples to demonstrate the degree of fractionation at the different wavelengths.
Laser ablation-ICP-MS is a sensitive and accurate technique for major to trace multi-element analysis at high spatial resolution on the scale of 10 µm. A wide variety of samples can be studied quantitatively, including minerals and their solid, liquid or melt inclusions as required for geochemical studies. As the desired spatial resolution increases, however, detection limits become severely constrained by the total amount of sample material reaching the ICP. Detection limits are therefore determined by the ablation rate and by the efficiency of removal of ablated aerosol particles from the ablation spot and their transport into the plasma. Properties of the carrier gas are known to affect the ablation process and the efficiency of particle transportation. This study explores the effects of different ablation-cell configurations and the use of helium, dry argon and argon moistened with water for the transport of aerosols into an ICP-MS, using a prototype 193 nm ArF excimer laser. Deposition of visible particles deposited around the ablation pit is significantly reduced when helium is used instead of argon. A moderate flux of helium through the chamber, mixed with moistened argon immediately downstream from the ablation chamber, leads to at least a 2-3-fold increase in the signal intensities across the entire mass range when compared with argon gas only. Background intensities above mass 85 are significantly reduced, but polyatomic interferences in the low mass region increase by an order of magnitude, owing to oxide formation caused by the water load. A high flux of helium, mixed just behind the ablation cell with dry argon, yields a 2-3-fold sensitivity enhancement, in addition to greatly reduced background intensity across the entire mass range. This results in one order of magnitude improvement in detection limits for most elements. These modifications permit the routine determination of minor concentrations of chlorine in microscopic fluid inclusions or the analysis of minerals, such as trace element concentrations in quartz (e.g., Na and Li down to 500 ng g
–1
, using a 40 µ ablation pit). Furthermore, this improved sensitivity has recently yielded the first quantitative determination of gold concentrations (∼0.1 µg g
–1
) and full rare-earth element patterns in single 25 µm fluid inclusions.
The composition and fractionation properties of dielectric aerosols generated by near-infrared femtosecond laser ablation of silicate glass (carrier gas: helium, 1 atm) have been examined. Aerosols were classified using low-pressure impaction of particles with diameters from 7 nm up to 7 μm. The element-selective analyses of impacted material has been restricted to minor matrix constituents (nominal concentration 4.5%) applying total reflection X-ray fluorescence. It has been found that for fluences larger than 5 J cm−2 the total Zn-, Ca-, Sr-, Ba-, and Pb-specific composition of these aerosols corresponds to that of the bulk material even though the size-dependent particle composition strongly altered. Typical deviations were of the order of 5–10%. In contrast, fluences below 5 J cm−2 usually resulted in stronger differences from the bulk composition indicating intensified fractionation during the ablation process. Our results furthermore demonstrate, that the major fraction of the aerosol mass is located within the mesoscopic size range, i.e. from 10 up to 100 nm, fairly independent on the fluence applied. However, the relative percentage of micrometer particles has been found to significantly decrease for higher fluences. Scanning electron microscopy of impacted brass particles moreover revealed a fractal-like structure of deposits. Implications for the classification of such structures using low-pressure impaction are discussed.