Zircon from diamondiferous kyanite gneisses of the Kokchetav massif: Revealing growth stages using an integrated cathodoluminescence–Raman spectroscopy–electron microprobe approach

Natural and synthetic iron oxides and iron hydroxides are important minerals for many industrial sectors (e.g. steel making, colors, pigment for coating, electronics, catalysis, soil, waste water and gas treatments, and medicine). In natural environments, such as iron ore mines or iron rich soils (laterites or bauxites), iron oxy-hydroxide associations are complex and evolve related to varying physico-chemical conditions, including. biological interactions. For efficient resource use, unambiguous multiscale characterization is indispensable. Synthetic iron oxides, produced for medical and electronic sector, needs to be failure-free pure phases, thus a continuous quality control is required. Complex iron oxy-hydroxide association can be related to various processes, topotactic transition, pseudomorphosis by substitution and alteration paramorphosis, and corrosions, leading to massive, porous, fibrous and acicular textures or poorly crystalline crusts.We present examples from iron ore deposits, where coupling of X-Ray diffraction (XRD) with scanning electron microscopy (SEM) and micro-Raman spectroscopy is a powerful tool to distinguish hematite, maghemite and magnetite at grain scale. Oxygen analyses by electron microprobe at (EMPA) fixed carbon coating thickness help to distinguish magnetite and hematite, and contribute with quantitative trace element analyses to chemically differentiate both oxides. At micro- and nano-scale, Transmission Electron Microprobe analyses coupled to X-Ray Diffraction (XRD) and Electron Energy Loss Spectroscopy (EELS) on nanometric inclusions can unambiguously identify various iron oxy-hydroxide phases. In Nickel-laterite and bauxite profiles, iron oxy-hydroxides (e.g. lepidocrocite, ferrihydrite, goethite&#8230;) are abundant and may form complex intergrowth with various types of phyllosilicates. Part of it host valuable metals such as Nickel. Combined XRF-XRD and Raman spectroscopy allow phase mapping and differentiation at micron scale of these phases, and even detect solid solutions (e.g. Ni-rich and Ni-poor goethite; El Mendili et al., 2019). Results from coupled laboratory analyses are necessary for building up data bases. They allow calibrating recently developed combined XRF-XRD-Raman benchtop systems. For industrial applications coupled and combined analyses will increase resource efficiency, and ensure a quality control for natural and synthetic iron oxide products. Such systems are recently developed by EU projects, such as SOLSA (www.solsa-mining.com).El Mendili, Y., Chateigner, D., Orberger, B., Gascoin, S, Bardeau, JF., Petit, S., Le Guen, M., Pilli&#232;re, H. (2019). Combined XRF, XRD, SEM-EDS, and Raman analyses on serpentinized harzburgite (Nickel Laterite Mine, New Caledonia): Implications for Exploration and Geometallurgy. ACS Earth and Space Chemistry. 3, 10, 2237-2249; DOI: 10.1021/acsearthspacechem.9b00014

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Electron Microprobe and Raman Spectroscopy Investigation of an Oxygen-Bearing Pt–Fe–Pd–Ni–Cu Compound from Nurali Chromitite (Southern Urals, Russia)

Microscopy and Microanalysis ◽

10.1017/s1431927615000513 ◽

2015 ◽

Vol 21 (5) ◽

pp. 1070-1079 ◽

Cited By ~ 3

Author(s):

Federica Zaccarini ◽

Giorgio Garuti ◽

Ronald J. Bakker ◽

Evgeny Pushkarev

Keyword(s):

Raman Spectroscopy ◽

Raman Spectra ◽

Electron Microprobe ◽

Platinum Group Element ◽

Southern Urals ◽

Group Element ◽

X Ray ◽

Chemical Zoning ◽

Ultramafic Complex ◽

Layered Sequence

AbstractOne grain, about 100×80μm in size, occurring in chromitite associated with the layered sequence of the Nurali mafic-ultramafic complex (Southern Urals, Russia) was investigated by electron-microprobe analyses and Raman spectroscopy. The grain is characterized by a spotty, rugged appearance and chemical zoning from which two compositions were calculated: (Pt0.35Pd0.26Fe0.22Cu0.01Ni0.05)0.98O1.02and (Fe0.90Pt0.58Ni0.28Pd0.13Cu0.08Rh0.01)1.98O1.02. In the lack of X-ray data, Raman spectroscopy established the presence of a diffuse 500–700 band and a sharp peak at 657 cm−1of relative wavenumber that strongly resemble the Raman spectra of synthetic PtO and PdO (palladinite). It is concluded that the Nurali grain probably represents a platinum group element (PGE) oxide, and does not consist of a mixture of PGE alloys with Fe oxide or hydroxide as reported for other natural PGE-O compounds.

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Crystal structure and Raman spectroscopic studies of OH stretching vibrations in Zn-rich fluor-elbaite

American Mineralogist ◽

10.2138/am-2020-7360 ◽

2020 ◽

Vol 105 (11) ◽

pp. 1622-1630 ◽

Cited By ~ 1

Author(s):

Adam Pieczka ◽

Andreas Ertl ◽

Bożena Gołębiowska ◽

Piotr Jeleń ◽

Jakub Kotowski ◽

...

Keyword(s):

Crystal Structure ◽

Raman Spectroscopy ◽

Electron Microprobe ◽

Integral Intensity ◽

Structure Refinement ◽

Gaussian Function ◽

Raman Shift ◽

Crystal Chemical ◽

Site Occupation ◽

Stretching Vibrations

Abstract Zinc-rich fluor-elbaite from Piława Górna, Poland, was studied by electron microprobe (EPMA), single-crystal X-ray diffraction (SREF), and Raman spectroscopy (RS) to check the possibility of the application of RS to draw crystal-chemical conclusions for Al-rich and Li-bearing tourmalines on basis of the O–H stretching vibrations in the spectral range 3400–3800 cm–1. This tourmaline, forming a thin metasomatic zone around gahnite, features varying compositions with a ZnO content reaching in the studied fragment of 5.70(12) wt%. The crystal structure of this Zn-rich fluor-elbaite [a = 15.921(1), c = 7.127(1) Å] was refined with a R1 value of 1.67%. Its formula was determined on the basis of electron-microprobe and structure refinement as (Na0.84☐0.14Ca0.01)XΣ1.00(Al1.06Li0.84Zn0.69Fe0.322+Mn0.09)YΣ3.00AlZ6(BO3)3(Si6TO18)(OH)3V(F0.65OH0.26O0.09)W. The deconvolution of the O–H stretching vibration bands, performed by fitting of an input model of component bands with Gaussian function shapes for the empirical spectrum, indicates that each of the three maxima assigned for VOH bonded to YAl3+, Y2+, and YLi+ and with the total integral intensity of at least 75% of the total OH content could be resolved into 1 to 3 bands, depending on the X-site occupation (vacancies, Na+, and Ca2+). The deconvolution indicates further that several low intense bands of WO–H modes above a Raman shift of 3600 cm–1, totally reaching ≤25%, are dependent on the occupation of triplets of YYY cations bonded to the hydroxyl. These WO–H modes are also influenced by the X-site occupation. Due to ordering of all octahedral cations (except Al) at the Y site and a complete occupation of the Z site by Al and the V site by OH, it seems possible to evaluate the Li and OH contents in a Al-rich and Li-bearing tourmaline directly from the Raman spectrum. By using the ratio VOHIYAlZAlZAl/(VOHIYZZ + WOHIYYY) as evaluated from RS, corresponding to the ratio YAl/V+WOH in the crystal, the formula of the Zn-rich fluor-elbaite can be calculated as (Na0.85☐0.14Ca0.01)XΣ1.00(Al1.11Y1.112+Li0.78)YΣ3.00AlZ6(BO3)3(Si6O18)(OH)3(F0.65OH0.13O0.22), where Y 2+ = Zn + Fe + Mn. The formula, determined only on basis of EPMA and deconvolution of RS in the O–H stretching bands, corresponds very well (≤1 SD range of EPMA) to the formula determined on basis of EPMA and SREF. This result implicates that the O–H stretching vibrations, measured by Raman spectroscopy, could be applied for Al-rich and Li-bearing tourmalines as a useful tool for providing additional information for determining the crystal-chemical formula. It is also very helpful when crystal structural data are not available.

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A reinvestigation of mayenite from the type locality, the Ettringer Bellerberg volcano near Mayen, Eifel district, Germany

Mineralogical Magazine ◽

10.1180/minmag.2012.076.3.18 ◽

2012 ◽

Vol 76 (3) ◽

pp. 707-716 ◽

Cited By ~ 9

Author(s):

E. V. Galuskin ◽

J. Kusz ◽

T. Armbruster ◽

R. Bailau ◽

I. O. Galuskina ◽

...

Keyword(s):

Crystal Structure ◽

Raman Spectroscopy ◽

Single Crystal ◽

Electron Microprobe ◽

Partial Substitution ◽

Chemical Formula ◽

Oh Groups ◽

X Ray ◽

Ray Methods ◽

Original Formula

AbstractNew electron-microprobe analyses of mayenite from the Ettringer Bellerberg volcano near Mayen in the Eifel district, Germany have high Cl contents and Raman spectroscopy indicates the presence of OH groups. Neither of these components is included in the generally accepted chemical formula, Ca12Al14O33. A refinement of the crystal structure by single-crystal X-ray methods reveals a previously unrecognized partial substitution. The O2 site which forms one of the apices of an AlO4 tetrahedron (with 3 × O1 sites) is replaced by 3 × O2a sites, which change the coordination of the central Al atom from tetrahedral to octahedral. This substitution is related to partial hydration of Ca12Al14O32Cl2 according to the isomorphic scheme (O2– + Cl–) ↔ 3(OH)–. The revised composition of Eifel mayenite is best described by the formula Ca12Al14O32–xCl2–x(OH)3x (x ∼0.75); the original formula, Ca12Al14O33, is inadequate. The analysed mineral can be considered to consist of endmember Ca12Al14O32Cl2 (62.5 mol.%) and endmember Ca12Al14O30(OH)6 (37.5 mol.%).

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Unique Association of Sulphosalts from the Kľačianka Occurrence, Nízke Tatry Mts., Slovak Republic

Minerals ◽

10.3390/min11091002 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1002

Author(s):

Jiří Sejkora ◽

Martin Števko ◽

Jaroslav Pršek ◽

Róbert Hovorič ◽

Emil Makovicky ◽

...

Keyword(s):

Raman Spectroscopy ◽

Powder Diffraction ◽

Electron Microprobe ◽

Slovak Republic ◽

X Ray ◽

Ore Minerals ◽

Ore Mineralization ◽

Ore Mineralogy ◽

Unique Association ◽

Hydrothermal Veins

Unique association of sulphosalts was discovered at the Kľačianka occurrence, Nízke Tatry Mts., Slovak Republic. It is bound to thin hydrothermal veins with Sb mineralization hosted by the Variscan muscovite-biotite granodiorite and granite of Prašivá type. Ore mineralogy and crystal chemistry of ore minerals are studied here by ore microscopy, X-ray powder diffraction, electron microprobe analyses, and Raman spectroscopy. The early ore mineralization composed of pyrite and arsenopyrite is hosted in quartz gangue and is followed by abundant association of sulfosalts. Stibnite, zinkenite, robinsonite (including Cu-bearing variety), jamesonite, scainiite, dadsonite, disulfodadsonite, rouxelite, chovanite, semseyite, boulangerite, geocronite, tintinaite (with low Bi contents), tetrahedrite-(Fe), tetrahedrite-(Zn), bournonite, chalcostibite, bismuthinite, and gladite in association with sphalerite and rare galena and gold are identified here. The chlorine-rich character of the described sulphosalt association is its characteristic phenomenon. It is represented not only by the occurrence of Cl-sulphosalt and dadsonite, but increased Cl contents were detected in boulangerite, chovanite, disulfodadsonite, robinsonite, rouxelite, scainiite, or tintinaite. The presence of oxygen-containing sulphosalts, such as rouxelite, scainiite and chovanite, is also interesting. The crystallization of these rare chloro-, oxy- and oxy-chloro-sulphosalts at the Kľačianka occurrence required very specific conditions (elevated O2/S2 fugacity) and high chlorine activity in ore-forming fluids.

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Use of Raman spectroscopy for determining the effects of herbicides on the carotenoid content in Chenopodium album and Abutilon theophrasti leaves

Acta herbologica ◽

10.5937/actaherb2001063v ◽

2020 ◽

Vol 29 (1) ◽

pp. 63-72

Author(s):

Filip Vranješ ◽

Ilinka Pećinar ◽

Steva Lević ◽

Sava Vrbničanin ◽

Dragana Božić

Keyword(s):

Raman Spectroscopy ◽

Chenopodium Album ◽

Abutilon Theophrasti ◽

Carotenoid Content ◽

Growth Stages ◽

Weed Species ◽

Leaf Analysis ◽

Wide Range ◽

Significant Difference ◽

Adequate Method

Raman spectroscopy has so far proved to be a suitable method for the analysis of carotenoids in a wide range of plant samples. This study aimed to determine whether the influence of mesotrione on the changes in carotenoid content of leaves in treated weed species Chenopodium album and Abutilon theophrasti can be detected using Raman spectroscopy. When the plants reached the targeted growth stages (C. album: 4 leaves, A. theophrasti: 2 leaves), Skaut herbicide (a.i. mesotrione 480 g l-1, SC) was applied in the amount of 120 g a.i. ha-1 in the tank mix with the adjuvant Alteox wet 40 (a.i. mineral oil (500 g L-1) + polyoxy alcohol (500 g L-1)), in the amount of 1 L ha-1. Leaf analysis, using Raman spectroscopy, was performed four times: on the 1st, 2nd, 3rd, and 7th day after the application of mesotrione. The intensity of the bands in the obtained Raman spectra, at positions 1007, 1155, and 1522 cm-1 in untreated and treated plants was analysed to determine the relative carotenoid content. The obtained results have shown that changes in the relative carotenoid content in the leaves of treated C. album plants can be detected as early as 3 days after the application of mesotrione, compared to the leaves of untreated plants of the same age. Meanwhile, a statistically significant difference for the same parameter in the leaves of treated A. theophrasti plants was evident at a later stage than in C. album, on the 7th day after the application of mesotrione. Consequently, this study has confirmed that Raman spectroscopy can be used as an adequate method for the rapid detection of the effect of herbicides on the content of carotenoids in the leaves of treated weed species.

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