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Inhibition of Sintering by Si During the Conversion of Si-Rich Ferrihydrite to Hematite
BET Ferrihydrite Si Sintering XPS
2011/12/2
Abstract: The distribution and chemical state of Si in a synthetic 2-line ferrihydrite with a Si/(Si + Fe) molar ratio of 0.11 was studied. Heat treatment under oxidizing conditions shows that Si-rich...
The Effect of Al on Fe Oxides. XIX. Formation of Al-Substituted Hematite from Ferrihydrite at 25C and pH 4 To 7
Al-Substituted Hematite Formation of Fe Oxide Hyperfine Fields Structural OH Synthesis of Fe Oxides Unit-Cell Size
2011/12/5
Abstract: Iron oxides in surface environments generally form at temperatures of 25 ?10癈, but synthesis experiments are usually done at higher temperatures to increase the rate of crystallization. To m...
Formation of Goethite and Hematite from Neodymium-Containing Ferrihydrite Suspensions
Ferrihydrite Goethite Hematite Neodymium Powder X-ray Diffractometry Rietveld Refinement Transmission Electron Microscopy
2011/12/8
Abstract: The effects of neodymium (Nd) on the transformation of ferrihydrite to iron oxides was studied. The possible isomorphous substitution of Nd3+ for Fe3+ in iron oxides was examined also. Nd wa...
Preparation and Properties of Hematite with Structural Phosphorus
α-Fe2O3 Hematite Color Crystal Chemistry Dissolution IR Spectra Structural P Structure
2011/12/7
Abstract: Synthetic hematites prepared in the presence of phosphate can incorporate phosphorus (P) in forms other than phosphate adsorbed by ligand-exchange on the crystal surface. To investigate the ...
Effect of Phosphate on the Crystallization of Hematite, Goethite, and Lepidocrocite from Ferrihydrite
Crystallization Ferrihydrite Goethite Hematite Lepidocrocite Phosphate
2011/12/7
Abstract: We investigated the crystallization of ferrihydrite prepared by hydrolysis of Fe(NO3)3 solutions containing phosphate. Crystallization was studied at different pH (3–9), temperatures (298, 3...
Epitaxial overgrowth of goethite on hematite synthesized in phosphate media: A scanning force and transmission electron microscopy study
Epitaxial goethite hematite synthesized phosphate media scanning force transmission electron microscopy study
2012/4/6
WeusedX-raydiffraction(XRD),scanningforcemicroscopy(SFM),transmissionelec-
tronmicroscopy(TEM),andcolortoinvestigatetheeffectofphosphateonthecrystalli-
zationrate,nature,andmorphologyofironoxidespre...
Comparison of Hematite Coagulation by Charge Screening and Phosphate Adsorption: Differences in Aggregate Structure
Coagulation Kinetics Fractal Aggregate Hematite Light Scattering Phosphate Adsorption
2011/12/22
Abstract: The formation and structure of hematite aggregates were examined by dynamic and static light scattering techniques. A large range in coagulation kinetics was studied by varying either indiff...
The redox state of Pinatubo dacite and the ilmenite-hematite solvus
redox state Pinatubo dacite ilmenite-hematite solvus
2012/4/5
Theoxidationstateofthe1991Pinatubodaciteandmanyotheroxidizedsilicicarc
volcanicrockshasbeenoverestimated.Wereproducethecompositionsofmagnetiteand
ferrianilmenitefoundinPinatubodacitebydoingcrystalli...
Hematite and Goethite from Duricrusts Developed by Lateritic Chemical Weathering of Precambrian Banded Iron Formations, Minas Gerais, Brazil
Hematite Goethite Laterite Mossbauer Spectrometry
2011/12/1
Abstract: The upper 15–20 m of a 200 m thick lateritic weathering profile on Precambrian itabirites of Capanema, Brazil, reveals a genetic pathway for the formation of hematitic and goethitic nodules ...
The electronic structure of hematite {001} surfaces: Applications to the interpretation of STM images and heterogeneous surface reactions
electronic structure hematite {001} surfaces Applications interpretation STM images heterogeneous surface reactions
2012/4/9
Scanning tunneling microscope (STM) images and scanning tunneling spectroscopy (STS) spectra of hematite (a-Fe203) surfaces werecalculated using ab-initio methods, not only to interpret experimentally...
Evolution of Hematite Surface Microtopography Upon Dissolution by Simple Organic Acids
Atomic force microscope Clay mineral surfaces Dissolution Hematite Organic acids
2011/12/1
Abstract: The surface microtopography of hematite over the course of dissolution in oxalic and citric acids was examined by in-situ and ex-situ atomic-force microscopy, In-situ imaging of the basal-pl...
Transformation of Akaganeite into Goethite and Hematite in the Presence of Mn
Akaganeite Goethite Hematite Manganese Transmission electron microscopy X-ray powder diffraction
2011/12/31
The interaction of Mn and akaganéite in neutral to alkaline media has been investigated using X-ray powder diffraction and transmission electron microscopy. Akaganéite transformed into goethite and/or...
Infrared Vibrations of Hematite Formed From Aqueous- and Dry-Thermal Incubation of Si-Containing Ferrihydrite
Ferrihydrite Hematite Infrared spectroscopy Morphology Silicon Thermal treatment
2012/1/4
Ferrihydrite samples having Si/Fe molar ratios ranging from 0 to 1 were synthesized by the reaction of Fe2(SO4)3 and Na2SiO3 with NaOH to an equilibrium pH of 8.2. Hematite formed by incubating the fe...
Transformation of Trace Element-Substituted Maghemite to Hematite
Hematite Iron Maghemite Magnetite Particle size Sintering Trace elements
2011/11/28
Abstract: X-ray powder diffraction (XRD), transmission electron microscopy, infrared spectroscopy, differential thermal analysis, and surface area (BET) measurements were employed to investigate the t...
Quantitative Determination of Hematite and Goethite in Lateritic Bauxites by Thermodifferential X-ray Powder Diffraction
Bauxite Goethite Hematite Iron Mineral analysis Thermal treatment X-ray powder diffraction
2012/1/9
An X-ray thermodifferential powder diffraction method for the quantitative determination of goethite and hematite in lateritic bauxites has been developed and consists of measuring the integrated inte...