Pigmenting agents in martian soils: Inferences from spectral, Mössbauer, and magnetic properties of nanophase and other iron oxides in Hawaiian palagonitic soil PN-9

1993 ◽  
Vol 57 (19) ◽  
pp. 4597-4609 ◽  
Author(s):  
Richard V. Morris ◽  
D.C. Golden ◽  
James F. Bell ◽  
Howard V. Lauer ◽  
John B. Adams
Keyword(s):  
Magnetic Properties ◽  
Iron Oxides

scholarly journals Morphology and Magnetic Properties of Ferriferous Two-Phase Sodium Borosilicate Glasses

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Alexander Naberezhnov ◽  
Nadezda Porechnaya ◽  
Viktor Nizhankovskii ◽  
Alexey Filimonov ◽  
Bernard Nacke
Keyword(s):  
Magnetic Properties ◽  
Iron Oxides ◽  
Channel Structure ◽  
Borosilicate Glasses ◽  
Melt Quenching ◽  
Two Phase ◽  
Furnace Charge ◽  
Self Assembling ◽  
Quenching Method ◽  
Drop Structure

This contribution is devoted to the study of morphology and magnetic properties of sodium borosilicate glasses with different concentrations (15, 20, and 25 wt.%) ofα-Fe2O3in an initial furnace charge. These glasses were prepared by a melt-quenching method. For all glasses a coexistence of drop-like and two-phase interpenetrative structures is observed. The most part of a drop structure is formed by self-assembling iron oxides particles. All types of glasses demonstrate the magnetic properties and can be used for preparation of porous magnetic matrices with nanometer through dendrite channel structure.

scholarly journals Influence of Hydrofluoric Acid Leaching and Roasting on Mineralogical Phase Transformation of Pyrite in Sulfidic Mine Tailings

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 513 ◽  
Author(s):  
Babak Koohestani ◽  
Ahmad Khodadadi Darban ◽  
Pozhhan Mokhtari ◽  
Esmaeel Darezereshki ◽  
Erol Yilmaz ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Phase Transformation ◽  
Iron Oxides ◽  
Mine Tailings ◽  
Hydrofluoric Acid ◽  
Surface Characterization ◽  
Acid Leaching ◽  
Roasting Process ◽  
Pyrite Content ◽  
Mineralogical Phase

Under the oxidative roasting process, pyrite, as a major mineral in sulfidic mine tailings, can transform to iron oxides. Generated iron oxides, if exhibiting enough magnetic properties, can be recovered via magnetic separation resulting in partial mine tailings valorization. However, due to the presence of various minerals and sintering possibility, it is advantageous to remove impurities and increase the pyrite content of mine tailings prior to the roasting procedure. In this case, hydrofluoric acid that has no influence on pyrite can be used to leach most inorganic minerals, including aluminosilicates. Therefore, this study investigated and compared the influence of the roasting process with and without hydrofluoric acid leaching pretreatment on mineralogical phase transformation of pyrite and magnetic properties of thermally generated minerals. Several tests and analyses were performed to study mineralogical phase transformation, morphology, elemental composition, surface characterization, and magnetic properties. Results of this study indicated that without acid leaching pretreatment, pyrite was mainly transformed to hematite. However, via acid leaching, fluorine, as a more electronegative element over oxygen, entered the compound and neglected the role of oxygen in thermal oxidation, instead reducing sulfur content of pyrite to only form pyrrhotite.

scholarly journals Impact of Gadolinium on the Structure and Magnetic Properties of Nanocrystalline Powders of Iron Oxides Produced by the Extraction-Pyrolytic Method

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4147
Author(s):  
Vera Serga ◽  
Regina Burve ◽  
Mikhail Maiorov ◽  
Aija Krumina ◽  
Ramūnas Skaudžius ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Thermal Treatment ◽  
Iron Oxides ◽  
Caproic Acid ◽  
Transformation Process ◽  
Nanocrystalline Powders ◽  
Preparation Conditions ◽  
Oxide Phases

Interest in magnetic nanoparticles is primarily due to their practical use. In this work, for the production of nanocrystalline powders of pure and gadolinium doped iron oxides, the extraction-pyrolytic method (EPM) was used. As a precursor, either iron-containing extract (iron (III) caproate in caproic acid) or its mixture with gadolinium-containing extract (gadolinium (III) valerate in valeric acid) was used. The mixed precursor contained 0.5 mol %, 2.5 mol %, 12.5 mol %, 50 mol %, and 75 mol % gadolinium in relation to the iron content. The formation of iron oxide phases, depending on the preparation conditions, was investigated. According to the results obtained, it was demonstrated that the presence of more than 2.5 mol % gadolinium additive in the mixed precursor inhibits the magnetite-to-hematite transformation process during thermal treatment. Produced samples were characterized by XRD and SEM methods, and the magnetic properties were studied.

scholarly journals The Influence of Synthesis Parameters on Structural and Magnetic Properties of Iron Oxide Nanomaterials

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 85 ◽  
Author(s):  
Laura Madalina Cursaru ◽  
Roxana Mioara Piticescu ◽  
Dumitru Valentin Dragut ◽  
Ioan Albert Tudor ◽  
Victor Kuncser ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Crystalline Phase ◽  
Annealing Treatment ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Order Of Magnitude

Magnetic iron oxides have been used in biomedical applications, such as contrast agents for magnetic resonance imaging, carriers for controlled drug delivery and immunoassays, or magnetic hyperthermia for the past 40 years. Our aim is to investigate the effect of pressure and temperature on the structural, thermal, and magnetic properties of iron oxides prepared by hydrothermal synthesis at temperatures of 100–200 °C and pressures of 20–1000 bar. It has been found that pressure influences the type of iron oxide crystalline phase. Thus, the results obtained by Mössbauer characterization are in excellent agreement with X-ray diffraction and optical microscopy characterization, showing that, for lower pressure values (<100 bar), hematite is formed, while, at pressures >100 bar, the major crystalline phase is goethite. In addition, thermal analysis results are consistent with particle size analysis by X-ray diffraction, confirming the crystallization of the synthesized iron oxides. One order of magnitude higher magnetization has been obtained for sample synthesized at 1000 bar. The same sample provides after annealing treatment, the highest amount of good quality magnetite leading to a magnetization at saturation of 30 emu/g and a coercive field of 1000 Oe at 10 K and 450 Oe at 300 K, convenient for various applications.

Nano-Iron Oxides Used for Environmental Applications

2013 ◽  
Vol 583 ◽  
pp. 3-8
Author(s):  
Andrei Predescu ◽  
Ecaterina Matei ◽  
Andra Mihaela Predescu ◽  
Andrei Berbecaru ◽  
Liana Vladutiu
Keyword(s):  
Magnetic Properties ◽  
Specific Surface ◽  
Surface Area ◽  
Iron Oxides ◽  
Toxic Metals ◽  
Core Shell ◽  
Industrial Wastewaters ◽  
Wastewaters Treatment ◽  
Acidic Conditions ◽  
Fast Removal

The paper emphasizes the importance of use the nano-iron oxides as treatment materials for wastewaters decontamination, having in mind the size of these compounds and specific surface area suitable for retaining toxic metals such as chromium or cadmium presented as major pollutants for industrial wastewaters. Also, the magnetic properties of the nano-iron oxides offer the possibility of a fast removal of these from the system, after wastewaters treatment. The obtaining of some core-shell composites with nano-iron oxides as core represent an advantage because of the dissolving tendency of the nano-iron oxides under acidic conditions, the situation being common to the industrial wastewaters.

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