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In the BSY-1 foil, hematite nanocrystals were identified by electron diffraction patterns in large pores (Fig. 2).Although some of them have an acicular morphology with a width up to 5 nm, no d-spacings of goethite can be found and indexed in the diffraction patterns (Fig. 2 d).The rest consists of island-like hematite nanocrystals (Fig. 2 e-f), and …
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Mineral and Technological Features of Magnetite−Hematite Ores.pdf. ... goethite, the iron content ranges from 51.93 to 62.78% with an. average value of 58.11%. The presence of intergrowths of.
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The iron oxides hematite, magnetite, and goethite were studied with density functional theory to establish a consistent set of structures for both the bulk mineral and …
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The energetics and kinetics of uranyl reduction on pyrite, hematite, and magnetite surfaces: A powder microelectrode study. ... The reactivity of Fe(II) associated with goethite formed during ...
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Compared with hematite and magnetite, goethite has a much more diverse range of textural forms and occurrences, and its influence on iron ore processing is less understood. Currently, most analysis of the effects of goethite on mine performance considers only the chemistry of the ore and not its textural components. Through improved textural ...
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Hematite, magnetite, goethite, and hyrogoethite exist in the form of ferrous oxide (FeO) after pre-reduction as shown in Figs. 12 and 13. Ferrous oxide is main components of reduction product. The psilomelane, pyrolusite exist as MnO after pre-reduction. Kaolinite, chlorite is recrystallized into iron olivine and hercynite after dehydration.
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Goethite to magnetite conversion occurred at 600 °C in a 40:60 CO/CO 2 gas atmosphere. • A + 62 wt% Fe blast furnace pellet concentrate was produced with > 88 …
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It should be mentioned that some magnetite ores in the Bafq and Gol-e-Gohar iron ores illustrate porous texture and have been altered, metamorphosed and oxidized to kenomagnetite, martite, hematite, rutile and goethite (Mohseni and Aftabi, 2015), thus the isotopic data (Peters et al., 2020), in particular the highly negative δO 17 (per mil ...
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Chicot, D. et al. Mechanical properties of magnetite (Fe3O4), hematite (α-Fe2O3) and goethite (α-FeOOH) by instrumented indentation and molecular dynamics analysis. Mater. Chem.
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Authigenic magnetite formed from microcrystalline goethite and hematite dominantly behaves as interacting single-domain particles, while nanophase goethite …
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Hematite was prepared by calcination of the obtained magnetite and its particles also had to be ground to sizes < 10 μm.The present study was undertaken with the aim of preparing magnetite and goethite of pigment particle size < 10 μm via water-soluble mill scale-derived precursors. Furthermore, maghemite and hematite could then be …
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The most frequent crystallographic preferred orientations developed during the progressive phase transformation of magnetite-hematite-goethite are described and analyzed in two natural samples of banded iron formations from Carajás Mineral Province. Microtextures of martitized grains containing the three phases and the microplaty matrix …
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The objectives of this study were to (1) characterize synthetic and natural iron oxides (hematite, magnetite), hydroxides (ferrihydrite, goethite, lepidocrocite, akaganéite), a carbonate (siderite), a sulfate (Na-jarosite), and ferric arsenates (scorodite, yukonite) using Raman spectroscopy; (2) record and analyze the spectral patterns of ...
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The chemical species involved in the present investigation are goethite, hematite and magnetite, since there are some reports in the literature suggesting the formation of magnetite when goethite is heated at temperatures close to 300 °C [22].These compounds are easily differentiated by their Raman spectra (Fig. 1 and Table 1), what …
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Recent work by Nunna et al. (2020) on a similar sample indicated that to complete the transformation of goethite to hematite and/or magnetite in microwave-assisted roasting, the soaking time varies between 10 and 30 min Here, microwave-assisted magnetizing roasting tests were carried out under gas mixtures comprising …
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ID Species Reference Link Year Locality Pressure (GPa) Temp (K) 0002226: Goethite: Gualtieri A, Venturelli P (1999) In situ study of the goethite-hematite phase transformation by real time synchrotron powder diffraction American Mineralogist 84 895-904 1999: 0: 298: 0002227: Goethite: Gualtieri A, Venturelli P (1999) In situ study of the goethite …
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In this chapter we will explore the relative stability of five iron oxides and oxyhydroxides, including magnetite, hematite, maghemite, goethite, and lepidocrocite, …
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Hematite, goethite, and magnetite are relatively stable and mostly exist as end-state products, whereas ferrihydrite, lepidocrocite, maghemite, schwertmannite, and patina are unstable in nature and …
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In this study, we aimed to test whether hematite and goethite growth is influenced by ambient magnetic fields of Earth-like values. Ferrihydrite was aged at 95 …
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Magnetite has a black‐brown color tone alike the melanin skin pigment, hematite reddish‐brown tone, and goethite yellowish‐brown tone. Iron oxide pigments have been used in arts and tattooing for thousands of years exemplified by …
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Journal of Hazardous Materials 141 (2007) 575–580 Arsenic sorption onto natural hematite, magnetite, and goethite Javier Gim´enez a,∗, Mar´ıa Mart´ınez a, Joan de Pablo a,b, Miquel Rovira b, Lara Duro c a Departament d'Enginyeria Qu´ımica, Universitat Polit`ecnica de Catalunya (UPC), Av. Diagonal 647, 08028 Barcelona, Spain b CTM Centre Tecnol` …
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Goethite or hematite are obtained either through a dissolution-crystallization process or in the solid state, through a topotactic transformation. Given the structural relationships observed between ferrihydrite and wustite and hematite, it is allowed to think that a structural continuity could exist between wustite Fe{sub (1-} {sub x} {sub )}O ...
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Optical microscopy and X-ray diffraction (XRD) studies of the roasted mass confirmed the formation of magnetite with simultaneous disappearance of the hematite and goethite phases. In the microwave …
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There is a transitional bed present from the thick to medium bedding dominated by hematite and goethite in some places. It comprises weathered magnetite laminations, hematite, and goethite laminations. Some of the BIF rocks have bands comprising a mixture of hematite and goethite. Some areas contain more hematite and …
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The magnetite, hematite and goethite capping all can be effective for the suppression of endogenous P release from sediment into OW under anoxic conditions, and most of P immobilized by the magnetite, hematite and goethite capping layers is …
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Legodi MA, de Waal D (2007) The preparation of magnetite, goethite, hematite and maghemite of pigment quality from mill scale iron waste. Dyes Pigment 74:161–168. Article Google Scholar Lopez M, Luis B, Pasteris JD, Biswas P (2009) Sensitivity of micro-Raman spectrum to crystallite size electrospray-deposited and post …
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Masses and botryoidal crusts of hematite with goethite occur at the Gilman Mine about 1.5 miles west of Spring Valley (NE SW SW Sec. 1 T.27N R.16W) (Rosenberg, 1991; Allen, 1909). ... 1977). — Hematite is found as "martite" pseudomorphs after magnetite in iron formation outcropping on mounds in the Black River Falls area such as in the NE ...
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From the bulk phase, it is known that under ambient conditions hematite (α-Fe 2 O 3) is the most stable phase, while wustite (Fe 1-x O) decomposes into metallic iron and magnetite (Fe 3 O 4) (Cornell and Schwertmann 2003).
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The iron oxides hematite, magnetite, and goethite were studied with density functional theory to establish a consistent set of structures for both the bulk mineral and key surfaces, characterize ...
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The transformation of goethite into hematite occurred at about 270 °C for the synthetic sample and at 310 °C for the natural brown sample. The weight changes were accompanied by slight changes in the magnetic susceptibility of both samples. ... The authors concluded that a good temperature for converting goethite into magnetite …
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