scholarly journals Erratum: A rapid method for quantifying single mineral phases in heterogeneous natural dusts using X-ray diffraction (Volume 24, Issue 1, pp. 17–23)

2009 ◽  
Vol 24 (2) ◽  
pp. 145-145
Author(s):  
Jennifer S. Le Blond ◽  
Gordon Cressey ◽  
Claire J. Horwell ◽  
Ben J. Williamson
Keyword(s):  
Rapid Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases

A rapid method for quantifying single mineral phases in heterogeneous natural dusts using X-ray diffraction

2009 ◽  
Vol 24 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Jennifer S. Le Blond ◽  
Gordon Cressey ◽  
Claire J. Horwell ◽  
Ben J. Williamson
Keyword(s):  
Rapid Method ◽  
Volcanic Ash ◽  
Health Hazard ◽  
Crystalline Silica ◽  
X Ray Diffraction ◽  
Synthetic Sample ◽  
X Ray ◽  
Mineral Phases ◽  
Pure Phases

Quantification of potentially toxic single mineral phases in natural dusts of heterogeneous composition is critical for health hazard assessment. For example, crystalline silica, a human carcinogen, can be present as respirable particles in volcanic ash such as quartz, cristobalite, or tridymite. A method to rapidly identify the proportions of crystalline silica within mixed dust samples, such as volcanic ash, is therefore required for hazard managers to assess the potential risk of crystalline silica exposure to local populations. Here we present a rapid method for quantifying the proportions of single phases in the mineral assemblage of mixed dusts using X-ray diffraction (XRD) with a fixed curved position-sensitive detector. The method is a modified version of the whole-pattern peak-stripping (PS) method (devised by Cressey and Schofield [Powder Diffr.11, 35–39 (1996)]) using an internal attenuation standard (IAS) but, unlike the PS method, it requires no knowledge of other phases present in the sample. Ten synthetic sample mixtures were prepared from known combinations of four pure phases (cristobalite, hematite, labradorite, and obsidian), chosen to represent problematic constituents of volcanic ash, and analyzed by XRD. Results of the IAS method were directly compared with those of the PS method. The proportions of cristobalite estimated using the methods were comparable and accurate to within 3 wt %. The new IAS method involved less sample preparation and processing and, therefore, was faster than the original PS method. It therefore offers a highly accurate rapid technique for determination of the proportions of individual phases in mixed dusts.

Texture measurements in Al2O3 using BEKP

1994 ◽  
Vol 52 ◽  
pp. 608-609
Author(s):  
M. D. Vaudin ◽  
J. P. Cline
Keyword(s):  
Neutron Diffraction ◽  
Rapid Method ◽  
Crystallographic Orientation ◽  
Specimen Surface ◽  
X Ray Diffraction ◽  
Anisotropic Crystal ◽  
X Ray ◽  
Verification Method ◽  
Crystal Properties ◽  
Backscattered Electron

The study of preferred crystallographic orientation (texture) in ceramics is assuming greater importance as their anisotropic crystal properties are being used to advantage in an increasing number of applications. The quantification of texture by a reliable and rapid method is required. Analysis of backscattered electron Kikuchi patterns (BEKPs) can be used to provide the crystallographic orientation of as many grains as time and resources allow. The technique is relatively slow, particularly for noncubic materials, but the data are more accurate than any comparable technique when a sufficient number of grains are analyzed. Thus, BEKP is well-suited as a verification method for data obtained in faster ways, such as x-ray or neutron diffraction. We have compared texture data obtained using BEKP, x-ray diffraction and neutron diffraction. Alumina specimens displaying differing levels of axisymmetric (0001) texture normal to the specimen surface were investigated.BEKP patterns were obtained from about a hundred grains selected at random in each specimen.

scholarly journals First Report on the Geologic Occurrence of Natural Na–A Zeolite and Associated Minerals in Cretaceous Mudstones of the Paja Formation of Vélez (Santander), Colombia

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Carlos Alberto Ríos-Reyes ◽  
German Alfonso Reyes-Mendoza ◽  
José Antonio Henao-Martínez ◽  
Craig Williams ◽  
Alan Dyer
Keyword(s):  
Natural Zeolite ◽  
Scanning Electron Micrographs ◽  
Total Sulfur ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
The World ◽  
Porosity And Permeability ◽  
First Time

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.

Deterioration of concrete containing limestone powder exposed to sulfate attack at ambient temperature

2021 ◽  
Vol 11 (5) ◽  
pp. 724-731
Author(s):  
Hemin Liu ◽  
Qian Huang ◽  
Liang Zhao
Keyword(s):  
Ambient Temperature ◽  
Sulfate Solution ◽  
Sulfate Attack ◽  
Limestone Powder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
Adverse Influence ◽  
Powder Content ◽  
Scanning Electron

This study investigates the deterioration of concrete containing limestone powder exposed to sulfate solution under ambient temperature (20~25 °C). Microstructure and mineral phases within the attacked concrete were measured by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). It was found that the addition of limestone powder increased the initial porosity of concrete. Consequently, a larger amount of SO2–4 ions diffused into the concrete containing limestone powder, and their degree of deterioration caused by sulfate attack increased with the increase in limestone powder content. At ambient temperature, gypsum and ettringite were the major attack products, respectively within the surface and nearsurface portions of concrete containing limestone powder, which was consistent with the products of sulfate attack within concrete without limestone powder. Therefore, the type and distribution of the attack products in concrete had not been revised due to the addition of limestone powder. Nevertheless, the adverse influence of limestone powder on the sulfate resistance of concrete, even at ambient temperature, should be considered. Furthermore, effective measures should be implemented to improve the durability of concrete containing limestone powder in this environment.

scholarly journals Crystal Chemistry and High-Temperature Behaviour of Ammonium Phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the Burned Dumps of the Chelyabinsk Coal Basin

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 486 ◽  
Author(s):  
Andrey A. Zolotarev ◽  
Elena S. Zhitova ◽  
Maria G. Krzhizhanovskaya ◽  
Mikhail A. Rassomakhin ◽  
Vladimir V. Shilovskikh ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Coal Basin ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Mineral Phases

The technogenic mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O from the burned dumps of the Chelyabinsk coal basin have been investigated by single-crystal X-ray diffraction, scanning electron microscopy and high-temperature powder X-ray diffraction. The NH4MgCl3·6H2O phase is monoclinic, space group C2/c, unit cell parameters a = 9.3091(9), b = 9.5353(7), c = 13.2941(12) Å, β = 90.089(8)° and V = 1180.05(18) Å3. The crystal structure of NH4MgCl3·6H2O was refined to R1 = 0.078 (wR2 = 0.185) on the basis of 1678 unique reflections. The (NH4)2Fe3+Cl5·H2O phase is orthorhombic, space group Pnma, unit cell parameters a = 13.725(2), b = 9.9365(16), c = 7.0370(11) Å and V = 959.7(3) Å3. The crystal structure of (NH4)2Fe3+Cl5·H2O was refined to R1 = 0.023 (wR2 = 0.066) on the basis of 2256 unique reflections. NH4MgCl3·6H2O is stable up to 90 °C and then transforms to the less hydrated phase isotypic to β-Rb(MnCl3)(H2O)2 (i.e., NH4MgCl3·2H2O), the latter phase being stable up to 150 °C. (NH4)2Fe3+Cl5·H2O is stable up to 120 °C and then transforms to an X-ray amorphous phase. Hydrogen bonds provide an important linkage between the main structural units and play the key role in determining structural stability and physical properties of the studied phases. The mineral phases NH4MgCl3·6H2O and (NH4)2Fe3+Cl5·H2O are isostructural with natural minerals novograblenovite and kremersite, respectively.

Characterization of mineral phases of agricultural soil samples of Colombian coffee using Mössbauer spectroscopy and X-ray diffraction

ICAME 2011 ◽  
2012 ◽  
pp. 593-598
Author(s):  
Humberto Bustos Rodríguez ◽  
Dagoberto Oyola Lozano ◽  
Yebrayl Antonio Rojas Martínez ◽  
Marlene Rivera Pinilla ◽  
German Antonio Pérez Alcázar
Keyword(s):  
Mössbauer Spectroscopy ◽  
Agricultural Soil ◽  
Mossbauer Spectroscopy ◽  
Soil Samples ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mößbauer Spectroscopy ◽  
Mineral Phases

Reichenbachite from Cornwall and Portugal

1994 ◽  
Vol 58 (392) ◽  
pp. 449-454 ◽  
Author(s):  
R. S. W. Braithwaite ◽  
G. Ryback
Keyword(s):  
Infrared Spectroscopy ◽  
Rapid Method ◽  
World Wide ◽  
British Isles ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Time

AbstractInfrared spectroscopy is a rapid method of distinguishing between pseudomalachite and its polymorphs reichenbachite and ludjibaite. This technique, backed by X-ray diffraction has shown that a number of specimens labelled ‘pseudomalachite’ from Cornwall, in particular from Old Gunnislake mine, are of reichenbachite, thus identified for the first time from the British Isles. Reichenbachite has also been identified with pseudomalachite from Miguel Vacas mine, Vila Viçosa, Evora, Portugal. Identification of pseudomalachite from a number of other localities world-wide has been confirmed, and some specimens have been shown to be arsenatian.

scholarly journals Radiation damage from long-term alpha particle bombardment of silicates – a microfocus XRD and Fe K-edge XANES study

2015 ◽  
Vol 79 (6) ◽  
pp. 1455-1466 ◽  
Author(s):  
W. R. Bower ◽  
C. I. Pearce ◽  
G. T. R. Droop ◽  
J. F. W. Mosselmans ◽  
K. Geraki ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Ion Irradiation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radiation Fields ◽  
Mineral Phases ◽  
Particle Damage ◽  
X Ray Absorption ◽  
Defect Densities

AbstractA detailed understanding of the response of mineral phases to the radiation fields experienced in a geological disposal facility (GDF) is currently poorly constrained. Prolongued ion irradiation has the potential to affect both the physical integrity and oxidation state of materials and therefore may alter a structure's ability to react with radionuclides. Radiohalos (spheres of radiation damage in minerals surrounding radioactive (α-emitting) inclusions) provide useful analogues for studying long term α-particle damage accumulation. In this study, silicate minerals adjacent to Th- and U-rich monazite and zircon were probed for redox changes and long/short range disorder using microfocus X-ray absorption spectroscopy (XAS) and high resolution X-ray diffraction (XRD) at Beamline I18, Diamond Light Source. Fe3+ → Fe2+ reduction has been demonstrated in an amphibole sample containing structural OH– groups – a trend not observed in anhydrous phases such as garnet. Coincident with the findings of Pattrick et al. (2013), the radiolytic breakdown of OH– groups is postulated to liberate Fe3+ reducing electrons. Across all samples, high point defect densities and minor lattice aberrations are apparent adjacent to the radioactive inclusion, demonstrated by micro-XRD.

scholarly journals Iron-containing phases in metallurgical and coke dusts as well as in bog iron ore

Nukleonika ◽  
2017 ◽  
Vol 62 (2) ◽  
pp. 187-195 ◽  
Author(s):  
Tadeusz Szumiata ◽  
Marzena Rachwał ◽  
Tadeusz Magiera ◽  
Katarzyna Brzózka ◽  
Małgorzata Gzik-Szumiata ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Spinel Structure ◽  
Iron Ore ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
Coke Plants ◽  
Wide Range ◽  
Specific Magnetic Susceptibility ◽  
Diffraction Patterns

Abstract Several samples of dusts from steel and coke plants (collected mostly with electro filters) were subjected to the investigation of content of mineral phases in their particles. Additionally, sample of bog iron ore and metallurgical slurry was studied. Next, the magnetic susceptibility of all the samples was determined, and investigations of iron-containing phases were performed using transmission Mössbauer spectrometry. The values of mass-specific magnetic susceptibility χ varied in a wide range: from 59 to above 7000 × 10−8 m-3·kg−1. The low values are determined for bog iron ore, metallurgical slurry, and coke dusts. The extremely high χ was obtained for metallurgical dusts. The Mössbauer spectra and X-ray diffraction patterns point to the presence of the following phases containing iron: hematite and oxidized magnetite (in coke and metallurgical dusts as well as metallurgical slurry), traces of magnetite fine grains fraction (in metallurgical dusts), amorphous glassy silicates with paramagnetic Fe3+ and Fe2+ ions, traces of pyrrhotite (in coke dusts), α-Fe and nonstoichiometric wüstite (in metallurgical slurry), as well as ferrihydrite nanoparticles (in bog iron ore). For individual samples of metallurgical dusts, the relative contributions of Fe2+/3+ ions in octahedral B sites and Fe2+ ions in tetrahedral A sites in magnetite spinel structure differs considerably.

A rapid method for the formation of Fe(II), Fe(III) hydroxycarbonate

Clay Minerals ◽  
1985 ◽  
Vol 20 (1) ◽  
pp. 147-151 ◽  
Author(s):  
R. M. Taylor ◽  
U. Schwertmann ◽  
H. Fechter
Keyword(s):  
Rapid Method ◽  
Hydrolysis Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Interlayer Anion ◽  
Diffraction Patterns ◽  
Dark Blue ◽  
Controlled Hydrolysis ◽  
Cation Ratio ◽  
The Ideal

Dark blue-green Fe(II)Fe(III) hydroxychlorides and -sulphates were described by Feitknecht & Keller (1950) and later by Bernal et al. (1959). To further understand the formation and transformation of these compounds, Taylor & McKenzie (1980) and Taylor (1980) prepared Fe(II)Al(III) and Fe(II)Fe(III) hydroxychlorides, -sulphates and -carbonates by a more controlled hydrolysis reaction. These compounds, referred to as ‘green rusts’ by Bernal et al. (1959), are isostructural with hydrotalcite. However, the X-ray diffraction patterns can vary with the M(II)/M(III) cation ratio as it departs from the ideal value of 3, and with the interlayer anion.

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