Calculated phase diagrams and thermodynamic properties of the Al 2 O 3 –Fe 2 O 3 –FeO system

Dreval, Liya; Zienert, Tilo; Fabrichnaya, Olga

doi:10.1016/j.jallcom.2015.10.017

Cited by 36 publications

(11 citation statements)

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“…The influence of the chemical starting composition on the onset of melting is also conspicuous: higher amounts of Fe 2 O 3 downshift the melting point to lower temperatures from 1723.15 K below 1623.15 K (1450°C below 1350°C). 21 A higher temperature favors the reduction in Fe 3+ to Fe 2+ . With increasing Fe 2+ concentration in FCAM-I the charge balance can only be maintained by the stepwise release of Ca 2+ which ultimately leads to the breakdown of the FCAM-I structure.…”

Section: Epma Resultsmentioning

confidence: 99%

Stability and calorimetric studies of silico‐ferrites of calcium aluminum and magnesium

et al. 2018

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In a systematic study on silico‐ferrites of calcium aluminum and magnesium (SFCA phases) this investigation focuses on synthesis of silicon‐free SFCA‐type compounds with low‐MgO contents (~1.00 apfu—atoms per formula unit). Previous studies revealed the existence of iron‐rich SFCA phases similar to the SFCA‐I structure with the chemical composition Ca3MgAl6Fe10O28 (Metall Mater Trans B. 2017;48:2207). The experimental results in the quaternary Fe2O3‐CaO‐Al2O3‐MgO system confirm large stability fields of 2 silicon‐free ferrites FCAM‐I and FCAM‐III, which are members of the homologous series M14+6nO20+8n (n = 1, 2). Starting with compositions corresponding to Ca3MgAlxFe16‐xO28 (with increasing aluminum content from x = 0‐12 apfu), it was possible to synthesize these phases with an x‐value ≥2 apfu, which corresponds to Al2O3 contents ≥7.14 wt%. Synthesis of pure silicon‐free ferrites with n = 1 (FCAM‐I) and 2 (FCAM‐III) and silicon‐bearing ferrites with n = 0 (SFCA) was possible. Samples were characterized by electron probe microanalysis, powder diffraction, and subsequently studied using relaxation calorimetry measurements in combination with differential scanning calorimetry for determination of the heat capacities and standard entropies S°(298). The corresponding values are S°(298) = 650.3 ± 4.6 J/mol·K for SFCA, S°(298) = 864.5 ± 6.1 J/mol·K for FCAM‐I, and S°(298) = 1206.2 ± 8.4 J/mol·K for FCAM‐III. These thermodynamic data are a step toward a rigorous quantitative thermodynamic modeling of the iron ore sintering process.

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Section: Epma Resultsmentioning

confidence: 99%

Stability and calorimetric studies of silico‐ferrites of calcium aluminum and magnesium

et al. 2018

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“…Feenstra et al (2005) reported the synthesis of the orthorhombic phase (Fe 0.53 Al 0.47 ) 2 O 3 coexisting with corundum (Al 0.88 Fe 0.12 ) 2 O 3 at 1300°C, which is slightly lower than the minimum temperature for stabilization of FeAlO 3 at 1318°C reported by Muan and Gee (1956) and Muan (1958). Dreval et al (2016) presented calculated phase diagrams in the Al 2 O 3 -Fe 2 O 3 -FeO system based on experimental data for relevant phases. These diagrams in the Al 2 O 3 -Fe 2 O 3 system are essentially the same as those of Muan (1958).…”

Section: Introductionmentioning

confidence: 91%

FeAlO3 under ultrahigh–temperature metamorphic conditions: Experimental evidence from the sillimanite–Fe2O3 and sillimanite–Fe3O4 systems

Kawasaki¹,

Adachi

Ohfuji

et al. 2019

Journal of Mineralogical and Petrological Sciences

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FeAlO 3a) was synthesized under ultrahigh-temperature metamorphic conditions. The assemblage of FeAlO 3 , SiO 2rich melt and vapor was obtained from a mixture of Rundvågshetta sillimanite and reagent-grade Fe 2 O 3 (weight ratio of 95:5) in Pt capsules at pressures of 5 and 9 kbar and a temperature of 1050°C under hydrous conditions. No hematite was found in these runs. Corundum was a rare crystallization product in the 9 kbar experiment. We also produced FeAlO 3 , SiO 2 -rich melt and vapor in the sillimanite-Fe 3 O 4 (weight ratio of 86:14) system in a AuPd capsule at 9 kbar and 1050°C under hydrous condition. A crystal domain comprising FeAlO 3 , corundum, magnetite-hercynite spinel and ulvöspinel formed at the bottom part of the charge due to contamination by Ti from titanium oxide, probably rutile, included within the sillimanite. This domain was in contact with melt among sillimanite crystals. Our results suggest that FeAlO 3 would be an index mineral for ultrahigh-temperature metamorphism of partially melted Fe-and Al-rich granulites generated under hydrous and oxidizing conditions.

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“…On the other hand superior concentrations of Fe 2 O 3 correspond to the two phase area in the phase diagram where the hematite and alumina are present separately and this is visible from the XRD. In the specimen having 8.7 wt.% of the Fe 2 O 3 the presence of the hematite structure is obvious [25].…”

Section: Characterization Of Alumina-iron Oxide Doped Particlesmentioning

confidence: 96%

Adsorption of anthraquinone dye AB111 from aqueous solution using synthesized alumina-iron oxide doped particles

et al. 2021

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Adsorption of anthraquinone dye Acid Blue 111 by alumina-iron oxide doped particles prepared by sol-gel method from aqueous solutions was studied. The adsorbent morphology was revealed by FESEM and the crystallographic phase is analyzed by the XRD technique. The effect of adsorbate and adsorbent concentrations, pH value, type of adsorbent and thermodynamic parameters on dye removal by adsorption was studied. The change of dye concentration during the adsorbtion was followed using the UV-Visible spectrophotometer. The change of the adsorbent surface before and after dye removal was observed using the Fourier Transformation-infrared spectroscopy (FT-IR). The adsorption kinetics is in accordance with the pseudo-second-order kinetics model. The Langmuir and Freundlich adsorption isotherm models were used to describe the adsorption process. The thermodynamic study of dye adsorption proves the process is spontaneous with exothermic nature.

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Calculated phase diagrams and thermodynamic properties of the Al 2 O 3 –Fe 2 O 3 –FeO system

Cited by 36 publications

References 50 publications

Stability and calorimetric studies of silico‐ferrites of calcium aluminum and magnesium

Stability and calorimetric studies of silico‐ferrites of calcium aluminum and magnesium

FeAlO<sub>3</sub> under ultrahigh–temperature metamorphic conditions: Experimental evidence from the sillimanite–Fe<sub>2</sub>O<sub>3</sub> and sillimanite–Fe<sub>3</sub>O<sub>4</sub> systems

Adsorption of anthraquinone dye AB111 from aqueous solution using synthesized alumina-iron oxide doped particles

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