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Use of Magnetite as an Ore of Iron. Most of the iron ore mined today is a banded sedimentary rock known as taconite that contains a mixture of magnetite, hematite, and chert.Once considered a waste material, taconite became an important ore after higher grade deposits were depleted.
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The evaluation will be based on volume changes caused by the conversions of magnetite to hematite and hematite to magnetite and microscopic studies of the resulting ore textures. In nearly all rock types where iron oxides occur, mutual replacement of magnetite and hematite are widespread.
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The effects of different concentrations of the hematite and magnetite on the magnetic properties of a set of mixtures (from 1 to 10 wt% magnetite) were then investigated by measuring the hysteresis loops, first order reversal curves (FORCs), thermal demagnetization, and isothermal remanent magnetization (IRM) curves. The three …
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Magnetite and maghemite are utilized in magnetic recording devices, whereas hematite is the most stable state of all and is commonly used in the sensor application [11], [12]. Both maghemite and magnetite exhibit a spinel crystal structure, whereas the latter contains both Fe 2+ and Fe 3+ cations.
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The irregular shape of the particles and the inward-growth hematite may have an impact on kinetic analysis. Monsen believes that the O 2− has limited mobility in magnetite and hematite, which is only possible to diffuse along the hematite−magnetite boundaries to a small extent. In pellet oxidation, the effect of inward-growth hematite is ...
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Abstract. Hematite microparticles are becoming increasingly important components in the soft matter field. The remarkable combination of magnetic and photocatalytic properties that characterize them, coupled with the variety of uniform and monodisperse shapes that they can be synthesized in, makes them a one of a kind colloidal model system.
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The magnetite–hematite ores of the Mikhailovskoye deposit are characterized by fine dissemination of ore and gangue minerals, the complexity of the structural and textural features and material composition, a low-level contrast in the magnetic properties of the separated minerals, ...
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Features of the synthesis of magnetite by hematite transformation were investigated by several methods, including ultrasonic chemical co-precipitation [10] and chemical reduction with carbohydrates [18], [19], with hydrogen [20], with carbon monoxide [21], and with other agents.
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Magnetic phases such as magnetite, hematite, goethite, and shamosite were recovered from nonmagnetic minerals of calcite, hydrogarnet and aluminosilicates by high- and/or medium-intensity selective magnetic separation to produce an iron-rich magnetic concentrate (Li et al., ...
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In sedimentary rocks, hematite can either have formed from have originally formed directly from direct precipitation out of marine waters, or as a concentration and enrichment deposit formed from groundwater. Regardless of its setting, hematite is usually found with other iron-bearing minerals, especially magnetite, goethite and siderite.
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Differences between hematite, magnetite, and other iron ore minerals. Hematite, magnetite, and other iron ore minerals differ in several key aspects, including their chemical composition, crystal structure, physical properties, and occurrences.
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Particular cases of phase transformation in iron oxide minerals, described as natural reactions of magnetite to hematite and synthetic reactions of hematite to magnetite, were chosen. It is observed, in both scenarios, that the transformation obeys the topotaxial and epitaxial relationship, which are well described for the iron oxide system.
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The mechanical properties of magnetite, hematite and goethite were studied by means of molecular dynamic analysis and instrumented indentation in order to corroborate the results. This study leads to the following concluding remarks:
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Magnetite: Magnetite (Fe3O4), another iron oxide mineral, is often associated with hematite. Both minerals are commonly found in banded iron formations (BIFs) and can occur together as alternating layers within the rock. Magnetite is also known to alter and oxidize into hematite through weathering processes.
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The concentration of magnetite/hematite particles within paleosol muscovite/chlorite grains and in aggregates of phyllosilicate fragments is much higher than that of the submicron iron oxides found on silicate surfaces. Interlayer magnetite particles are dominantly prism-shaped with aspect ratios >~4. The authigenic magnetite must be …
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Magnetite projects in Australia have experienced a troubled history and could not compete with hematite projects because of the high capital cost and higher operating cost. However, going forward, magnetite is projected to sell at a premium and traditional hematite could face diminishing markets.
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However, the existing magnetic and color reflectance property framework for hematite is based largely on stoichiometric hematite and tends to neglect the effects of cation substitution, which occurs widely in natural hematite and influences the physical properties of hematite.
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