The Relevance of Proton Induced X-Ray Analysis to the Study of Separate Mineral Phases

The sensitivity of proton induced X-ray analysis (PIXE) as a multi-element, non-destructive technique has been exhaustively reviewed recently. This follows the pioneering work of Johansson et al. in this field, in which sensitivities of 10-12g were announced. Between the dates of these two references (1970 and 1976 respectively), numerous papers have been published on the use of this technique and on the optimization of experimental conditions (choice of incident particle and energy in particular). The wide range of analytical applications reported at the Lund conference showed conclusively that PIXE has established itself as a viable and powerful analytical method.

Download Full-text

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 ◽

10.3390/cryst11020218 ◽

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.

Download Full-text

Spectral Tomography for 3D Element Detection and Mineral Analysis

Minerals ◽

10.3390/min11060598 ◽

2021 ◽

Vol 11 (6) ◽

pp. 598

Author(s):

Jose R. A. Godinho ◽

Gabriel Westaway-Heaven ◽

Marijn A. Boone ◽

Axel D. Renno

Keyword(s):

Energy Spectrum ◽

3D Imaging ◽

X Rays ◽

3D Images ◽

Characterization Methods ◽

X Ray ◽

Additional Information ◽

Mineral Phases ◽

Spectral Computed Tomography

This paper demonstrates the potential of a new 3D imaging technique, Spectral Computed Tomography (sp-CT), to identify heavy elements inside materials, which can be used to classify mineral phases. The method combines the total X-ray transmission measured by a normal polychromatic X-ray detector, and the transmitted X-ray energy spectrum measured by a detector that discriminates between X-rays with energies of about 1.1 keV resolution. An analysis of the energy spectrum allows to identify sudden changes of transmission at K-edge energies that are specific of each element. The additional information about the elements in a phase improves the classification of mineral phases from grey-scale 3D images that would be otherwise difficult due to artefacts or the lack of contrast between phases. The ability to identify the elements inside the minerals that compose ore particles and rocks is crucial to broaden the application of 3D imaging in Earth sciences research and mineral process engineering, which will represent an important complement to traditional 2D imaging mineral characterization methods. In this paper, the first applications of sp-CT to classify mineral phases are showcased and the limitations and further developments are discussed.

Download Full-text

SEM-based mineralogical mapping at the submicrometer-scale of modern Sardinian stromatolites

10.5194/egusphere-egu21-7169 ◽

2021 ◽

Author(s):

Juliette Debrie ◽

Dimitri Prêt ◽

Karim Benzerara ◽

Jean Paul Saint Martin

Keyword(s):

Mineralogical Composition ◽

Treatment Method ◽

Heterogeneous Distribution ◽

X Ray ◽

Mineral Phases ◽

Saint Martin ◽

History Of ◽

Phase Recognition ◽

Mineral Mixtures ◽

Insight Into

Stromatolites, i.e. macroscopically laminated carbonate rocks formed by diverse microbial communities, are particularly emblematic geobiological materials since they are the oldest evidence of life-mineral interactions, dated up to 3.5 Gyrs ago. &#160;They are found throughout the history of the Earth and have received strong attention because they provide precious information about microbial paleobiodiversity and paleoenvironments. However, while this information is interpreted based on our knowledge about modern analogs, the latter remains very incomplete. Here, we studied recently discovered modern stromatolites from Mari Ermi1, a coastal pond in Western Sardinia, that seasonally experience severe evaporation and broad salinity variations. For this purpose, we explored the mineralogical composition of these unique sedimentary archives and its spatial variations in order to gain better insight into how mineral phases record the conditions and processes of their formation. We investigated the heterogeneous distribution of minerals using quantitative X-ray chemical maps provided by energy dispersive x-ray spectrometry analyses coupled with scanning electron microscopy (SEM-EDXS). Hyperspectral maps were analyzed using an innovative data treatment method 2 allowing phase recognition within the complex mineral mixtures and solid solutions encountered. This method provided quantitative data on&#160;spatial distribution, modal content and associated calculated unit formulas for each identified mineral and phase with a hundred nanometer resolution. Based on these results, we will discuss the origin of the laminations in the stromatolites.Reference:1. Saint Martin, J.-P. & Saint Martin, S. Geo-Eco-Marina 21, 35&#8211;53 (2015a).2. Pr&#234;t, D. et al. American Mineralogist 95, 1379&#8211;1388 (2010).

Download Full-text

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

Materials Express ◽

10.1166/mex.2021.1963 ◽

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.

Download Full-text

The mineralogical and fabric analysis of ancient pottery artifacts

Cerâmica ◽

10.1590/s0366-69132011000100008 ◽

2011 ◽

Vol 57 (341) ◽

pp. 56-62 ◽

Cited By ~ 11

Author(s):

R. Palanivel ◽

U. Rajesh Kumar

Keyword(s):

Firing Temperature ◽

Tamil Nadu ◽

Thermal Characteristic ◽

Inert Atmosphere ◽

X Ray ◽

Ancient Pottery ◽

Mineral Phases ◽

Fabric Analysis ◽

Physical Attributes ◽

Xrd Studies

The present investigation is carried out to estimate the firing temperature and conditions of firing of ancient pottery shreds excavated recently from Sembiankandiyur, Tamil Nadu, India. FTIR and XRD studies have been attempted on these shreds to characterize the mineral composition of the pottery artifacts in respect of their different physical attributes. The firing temperature and conditions were inferred from the mineral phases of the samples exhibited by the infrared spectra and X-ray diffractograms recorded in as received state. TG-DTA is the complementary technique to elucidate the firing temperature from the thermal characteristic reactions such as dehydration, decomposition and transformations of minerals under the controlled firing of the samples in inert atmosphere.

Download Full-text

Evaluation of Tanzania local ceramic raw materials for high voltage porcelain insulators production

Cerâmica ◽

10.1590/0366-69132018643722427 ◽

2018 ◽

Vol 64 (372) ◽

pp. 570-576

Author(s):

B. Ngayakamo ◽

S. E. Park

Keyword(s):

High Voltage ◽

Bending Strength ◽

Raw Materials ◽

Microstructural Characterization ◽

Dielectric Strength ◽

Pressing Method ◽

X Ray ◽

Mineral Phases ◽

Porcelain Insulators ◽

High Voltage Porcelain

Abstract This study evaluated the potential of locally sourced-ceramic raw materials in Tanzania, Pugu kaolin, Same clay, vermiculite and feldspar, for production of high voltage porcelain insulators. The chemical, mineral phases and microstructural characterization of raw materials and porcelain samples were carried out using the X-ray fluorescence, X-ray diffraction, and scanning electron microscopy techniques, respectively. The mineral phases of the fired porcelain sample identified were mullite and quartz. The porcelain bodies were fabricated using the dry pressing method by varying the composition of the selected ceramic raw materials. The physical-mechanical properties and dielectric strength were measured for each porcelain sample. The sample with the composition of 20% Pugu kaolin, 20% Same clay, 20% vermiculite and 40% feldspar was found to have the dielectric strength of 50.8 kV.mm-1, bending strength of 20 MPa and water absorption of 0.46%, which satisfies the main requisite properties for high voltage porcelain insulators.

Download Full-text

Combining selective sequential extractions, X-Ray Absorption Spectroscopy, and X-Ray Powder Diffraction for Cu (II) speciation in soil and mineral phases

EURASIAN JOURNAL OF SOIL SCIENCE (EJSS) ◽

10.18393/ejss.286544 ◽

2017 ◽

Vol 6 (2) ◽

pp. 114-114 ◽

Cited By ~ 1

Author(s):

Tatiana Minkina ◽

Dina Nevidomskaya ◽

Alexander Soldatov ◽

David Pinskii ◽

Fariz Mikailsoy ◽

...

Keyword(s):

Absorption Spectroscopy ◽

Powder Diffraction ◽

Sequential Extractions ◽

X Ray ◽

Mineral Phases ◽

X Ray Absorption

Download Full-text

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 ◽

10.3390/min9080486 ◽

2019 ◽

Vol 9 (8) ◽

pp. 486 ◽

Cited By ~ 2

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.

Download Full-text

Iron Transformations Induced by an Acid-Tolerant Desulfosporosinus Species

Applied and Environmental Microbiology ◽

10.1128/aem.06337-11 ◽

2011 ◽

Vol 78 (1) ◽

pp. 81-88 ◽

Cited By ~ 29

Author(s):

Doug Bertel ◽

John Peck ◽

Thomas J. Quick ◽

John M. Senko

Keyword(s):

Mine Drainage ◽

Low Ph ◽

Content Type ◽

X Ray ◽

First Order ◽

Geochemical Conditions ◽

Sulfate Reducing ◽

Mineral Phases ◽

Magnetic Analysis ◽

Acid Tolerant

ABSTRACTThe mineralogical transformations of Fe phases induced by an acid-tolerant, Fe(III)- and sulfate-reducing bacterium,Desulfosporosinussp. strain GBSRB4.2 were evaluated under geochemical conditions associated with acid mine drainage-impacted systems (i.e., low pH and high Fe concentrations). X-ray powder diffractometry coupled with magnetic analysis by first-order reversal curve diagrams were used to evaluate mineral phases produced by GBSRB4.2 in media containing different ratios of Fe(II) and Fe(III). In medium containing Fe predominately in the +II oxidation state, ferrimagnetic, single-domain greigite (Fe3S4) was formed, but the addition of Fe(III) inhibited greigite formation. In media that contained abundant Fe(III) [as schwertmannite; Fe8O8(OH)6SO4·nH2O], the activities of strain GBSRB4.2 enhanced the transformation of schwertmannite to goethite (α-FeOOH), due to the increased pH and Fe(II) concentrations that resulted from the activities of GBSRB4.2.

Download Full-text