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high pressure magnetite

  • Novel high pressure magnetic measurements with application ...

    May 22, 2002· [1] We report a novel system designed to measure reversible magnetic susceptibility of micronsized samples under high pressures in a diamond anvil cell. We find that magnetite reversible hysteresis parameters vary <15% below 0.6 to 1.0 GPa, while at higher pressures significant increases occur in (1) bulk coercivity (Hc) and (2) the ratio of saturation remanent magnetization (Mrs) to ...

  • Equation of state of magnetite and its high-pressure ...

    Fe3O4has been studied by high-pressure diffraction to 43 GPa. No major changes in the spinel-type structure of magnetite is observed below 21.8 GPa. At higher pressure a sluggish transition to a high-pressure

  • US6523502B1 - Exfoliated magnetite removal system and ...

    A method of controllable cooling of a boiler ( 10 ) and removing exfoliated magnetite from the boiler tubes ( 30, 31 ) employs flowing dry gas through the boiler tubes ( 30, 31 ) at a flow velocity above the terminal velocity of the magnetite flakes as the boiler ( 10 ) is cooled from a temperature above the temperature at which exfoliation occurs.

  • Evolution of electronic and magnetic properties of nominal ...

    May 19, 2020· exposed to extreme conditions such as high pressure and temperature environments [3]. Iron-oxide magnetite (Fe 3O 4) is a naturally occurring, iron-rich, magnetic mineral. Nano counterparts of magnetite Journal of Physics: Condensed Matter Evolution of electronic and magnetic properties of nominal magnetite nanoparticles at high pressure probed by

  • Highpressure study of stability of magnetite by ...

    May 01, 2004· The calculations predict that the highpressure phase of magnetite (hFe 3 O 4) becomes unstable with respect to hFe 2 O 3 + FeO at pressures higher than 50 GPa. The 298 K pressurevolume isotherm of magnetite derived from the compression experiment is given by K T = 217(7) GPa for the fixed K 0 = 4.

  • Magnetite: Mineral information, data and localities.

    Haavik C, Stolen S, Fjellvag H, Hanfland M, Hausermann D (2000) Equation of state of magnetite and its high-pressure modification: Thermodynamics of the Fe-O system at high pressure American Mineralogist 85 514-523: 2000: 2.3: 293: 0002403: Magnetite

  • Magnetite - Wikipedia

    Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe 3 O 4 is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. It is the most magnetic of all the naturally occurring minerals on Earth. Naturally magnetized pieces of magnetite, called lodestone, will attract small pieces of ...

  • Abnormal elastic and vibrational behaviors of magnetite at ...

    Sep 04, 2014· Magnetite exhibits unique electronic, magnetic, and structural properties in extreme conditions that are of great research interest. Previous studies have suggested a number of transitional models, although the nature of magnetite at high pressure remains elusive.

  • (PDF) Processing of Magnetite Iron OresComparing Grinding ...

    Implementing high pressure grinding rolls in iron mining and electric and diesel hybrid haul trucks in underground gold mining and potash mining have the most favorable greenhouse gas abatement ...

  • Spin state of iron in Fe${}_{3}$O${}_{4}$ magnetite and $h ...

    Apr 22, 2013· The high-pressure behavior of magnetite has been widely debated in the literature. Experimental measurements have found conflicting high-pressure transitions: a charge reordering in magnetite from inverse-spinel to normal-spinel [Pasternak et al., J. Phys. Chem. Solids 65, 1531 (2004); Rozenberg et al., Phys. Rev. B 75, 020102 (2007)], iron high-spin to intermediate-spin transition in ...

  • Effect of high pressure on the crystal structure and ...

    of magnetite below 25 GPa, two possible scenarios have been heavily discussed in the literature to explain the high-pressure behavior of magnetite. The first hypothesis is a transition from the inverse type (IT) of spinel to the normal type (NT) at pressures 1020 GPa (Rozenberg et al. 2007; Pasternak et al. 2003). Analysis of pow -

  • Experimental determination of the reaction 2magnetite ...

    respectively, at 298 K and I bar. The assemblage almandine * kyanite + magnetite + quartz can serve as an O barometer in high-grade rocks, such as granulites, where the temperature and pressure of recrystallization are independently known. INrnonucrroN Almandine garnet

  • Electrical resistance of single-crystal magnetite (Fe 3 O ...

    Apr 07, 2016· Abstract. We measured the pressure dependence of electrical resistance of single-crystal magnetite (Fe 3 O 4) under quasi-hydrostatic conditions to 100 GPa using low-temperature, megabar diamond-anvil cell techniques in order to gain insight into the anomalous behavior of this material that has been reported over the years in different high-pressure experiments.

  • Effect of high pressure on the crystal structure and ...

    of magnetite below 25 GPa, two possible scenarios have been heavily discussed in the literature to explain the high-pressure behavior of magnetite. The first hypothesis is a transition from the inverse

  • Magnetite - an overview | ScienceDirect Topics

    Limited research on the effect of high pressure and salinity on solubility of magnetite has been conducted. Measuring the magnetite solubility has proven to be more difficult than that of other oxides, such as NiO, due to the reductive dissolution of magnetite from Fe(III) to Fe(II) [32]. Thus the reduction potential of the entire system plays ...

  • Phys. Rev. B 50, 6446 (1994) - High-pressure phase of ...

    Sep 01, 1994· M\"oss spectroscopy and x-ray diffraction were employed to investigate the magnetic and structural properties of the high-pressure monoclinic phase of magnetite. Measurements were performed to 66 GPa at 300 K using diamond anvil cells. Based primarily upon the M\"oss parameters, the following features of the high-pressure phase were deduced.

  • Discovery of the recoverable high-pressure iron oxide ...

    Oct 18, 2011· Although the high-pressure polymorph of magnetite is known to be a semiconductor (26, 27), a detailed account of the electronic structure of Fe 4 O 5 is beyond the scope of this study and will be the subject of a forthcoming investigation along with experimental efforts.

  • AMCSD Search Results - RRUFF

    Equation of state of magnetite and its high-pressure modification: Thermodynamics of the Fe-O system at high pressure: Sample at P = 30.3 GPa _database_code_amcsd 0002415: 8.0636 8.0636 8.0636 90 90 90 *Fd3m.125 .125 .125: atom x y z: Fe(tet) .125 .125 .125: Fe(oct) .5 .5 .5 ...

  • Influence of High Conductive Magnetite Impurity on the ...

    Jan 13, 2019· percentages of magnetite (0, 3, 5, 7, 10, 20, and 100) was homogenously mixed in the agate mortar for 2 h, hot-pressed and sintered in YJ-3000t multi-anvil high-pressure apparatus. Powder mixtures of reagent grade magnetite and well-characterized olivine were hot-pressed at

  • Abnormal Elastic and Vibrational Behaviors of Magnetite at ...

    Magnetite exhibits unique electronic, magnetic, and structural properties in extreme conditions that are of great research interest. Previous studies have suggested a number of transitional models, although the nature of magnetite at high pressure remains elusive.

  • Iron spin transitions in high-pressure magnetite - NASA/ADS

    The results on spin transitions in magnetite are important for understanding Fes spin behavior in the lower mantle and better characterizing high-pressure regimes like subduction zones or other Fe-rich regions. The results could impact magnetotelluric measurements and geodynamic models. [1]

  • Magnetic and electronic properties of magnetite across the ...

    Mar 14, 2019· An application of high pressure affects anomalously the behavior of magnetic and electronic properties of magnetite, ultimately leading to a structural phase transition above P ~ 25

  • Pressure-induced crystal structure and spin-state ...

    Magnetite (Fe(3)O(4)) is one of the oldest known magnetic materials and magnetic minerals, yet its high pressure behaviors are still not clear. In particular, the crystal structure of the high-pressure phase has remained contentious.

  • Synthesis of quenchable high-pressure form of magnetite (h ...

    Cubic inverse-spinel magnetite transforms under pressure to orthorhombic normal-spinel magnetite, h-Fe3O4 ( e.g. Fei et al. 1999; Bengtson et al. 2013). The pressure at which the transition takes place is still controversial. The high-pressure form is reported to be not quenchable to ambient conditions. We report the synthesis of h-magnetite which incorporates considerable amounts of ...

  • Abnormal Elastic and Vibrational Behaviors of Magnetite at ...

    Sep 04, 2014· High-pressure HERIX spectra of the single-crystal magnetite platelet with the pre-oriented (100) crystallographic plane were measured up to 19 GPa in a DAC for the lower momentum transfer (Q) part ...

  • Cementite Formation from Magnetite under High Pressure ...

    2. Experimental. High pressure magnetic suspension thermogravimetric analysis (TGA) system was used for the kinetic study of Fe 3 C formation by measuring the weight change with an accuracy of 1 μg. In the magnetic suspension balance system, a measuring microbalance is separated from a reacting cell and the suspension force is transmitted without direct contact from the pressurized reacting ...

  • Cementite Formation from Magnetite under High Pressure ...

    Cementite Formation from Magnetite under High Pressure Conditions Dong-Yuk KIM, Yoon-Uk HEO and Yasushi SASAKI* Graduate Institute of Ferrous Technology, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang, 790-784 Korea (South). (Received on November 26, 2012; accepted on March 15, 2013) Measurements have been made of the ...

  • Water Handbook - Preboiler & Industrial Boiler Corrosion ...

    Magnetite forms on boiler system metal surfaces from the following overall reaction: 3Fe + ... High-pressure alkaline water is an effective means of cleaning the fireside areas. Before alkaline water is used for this purpose, a rinse should be made with fresh water of neutral pH to prevent the formation of hydroxide gels in the deposits (these ...

  • Equation of state of magnetite and its high-pressure ...

    Fe 3 O 4 has been studied by high-pressure diffraction to 43 GPa. No major changes in the spinel-type structure of magnetite is observed below 21.8 GPa. At higher pressure a sluggish transition to a high-pressure modification, h-Fe 3 O 4, is observed.The X-ray diffraction pattern of the high-pressure modification is consistent with the orthorhombic unit cell (CaMn 2 O 4-type structure, space ...

  • Pressure effect on magnetic hysteresis parameters of ...

    May 02, 2015· To investigate pressure effects on the magnetic properties of SD magnetite, in situ magnetic hysteresis measurements of SD magnetite under high pressures of up to 1 GPa were conducted, using the high-pressure cell specially designed for the MPMS. The natural plagioclase crystals containing nearly stoichiometric and non-interacting SD magnetite ...

  • Revision 2 2 Synthesis of quenchable high-pressure form of ...

    59 The discovery of the high-pressure Fe-oxide Fe4O5 (Lavina et al. 2011) revealed that the Fe-60 oxide phase relations, especially at high pressures, are still poorly understood. Under ambient 61 conditions, the Fe-oxides FeO (wüstite), Fe3O4 (magnetite), and Fe2O3 (hematite) are stable 62 and form complex defect structures.

  • Abnormal elastic and vibrational behaviors of magnetite at ...

    Sep 04, 2014· On the other hand, high-pressure studies at room temperature have also suggested a number of electronic, magnetic, and structural transitions in magnetite including the inverse-normal spinel transition 9,14,15, the high-spin to intermediate-spin transition 16,19, the enhanced delocalization or charge ordering of the 3d electrons of the iron ...

  • Metallization of magnetite (Fe3O4) under high pressure ...

    Jun 07, 2001· Electrical resistivity measurements have been made on a good qualified single crystalline magnetite (Fe 3 O 4) at temperatures from 300 down to 3.0 K under pressure up to 10 GPa. A steep change in resistivity at the Verwey transition temperature has been observed at pressure below 6.5 GPa, which shows a quite distinct result reported in prior work. Moreover, the Verwey transition temperature ...

  • In situ observation of the breakdown of magnetite (Fe3O4 ...

    the high-pressure BreAKdoWn oF mAgnetite Two experiments were performed following similar pressure-temperature paths; the paths for Mag_1 and Mag_2 are presented in Figure 1. Sample Mag_1 was compressed to 12 GPa (i.e., beyond the stability field of magnetite, Schollenbruch et al. 2011) and then heated up to a temperature of about 1200 K. In a

  • High-Pressure crystal chemistry of spinel (MgAl 2 O 4 ...

    High-pressure crystal structures and compressibilities have been determined by x-ray methods for MgAl2O4 spinel and its isomorph magnetite, Fe3O4. The measured bulk moduli, K, of spinel and magnetite (assuming K=4) are 1.94±0.06 and 1.86±0.05 Mbar, respectively, in accord with previous ultrasonic determinations. The oxygen u parameter, the only variable atomic position coordinate in the ...

  • (PDF) Formation of iron hydride and high-magnetite at high ...

    Formation of iron hydride and high-magnetite at high pressure and temperature. Physics of the Earth and Planetary Interiors, 2004. Surendra Saxena. Download PDF. Download Full PDF Package. This paper. A short summary of this paper. 37 Full PDFs related to this paper. READ PAPER.

  • Highpressure study of stability of magnetite by ...

    May 01, 2004· The calculations predict that the highpressure phase of magnetite (hFe 3 O 4) becomes unstable with respect to hFe 2 O 3 + FeO at pressures higher than 50 GPa. The 298 K pressurevolume isotherm of magnetite

  • Prevent Magnetite From Plugging Your Steam And Water System

    Typically in these applications, low pressure is less than ~ 100psig, and low temperature is less than 120°F (49°C), with high pressures being up to 5000 psig. As mentioned above, magnetite physically can be removed from the system in three different ways: Strainers

  • Water Handbook -Boiler Deposits: Occurrence And Control | SUEZ

    This is usually enough to solubilize some condensate iron contamination. The chelation of magnetite (the oxide formed under boiler conditions-a mix of Fe2O3 and FeO) is possible because the chelant combines with the ferrous (FeO) portion of the magnetite. Overfeed (high levels) of chelant can remove large quantities of iron oxide.