Thermodynamic optimization of the Al2O3–FeO–Fe2O3–SiO2 oxide system

Prostakova, Viktoria; Shishin, Denis; Shevchenko, Maksym; Jak, Evgueni

doi:10.1016/j.calphad.2019.101680

Cited by 30 publications

(9 citation statements)

References 52 publications

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“…Compared with the surrounding surface, the radial whiskers have a lower Si content and a higher Al content. According to the previous literature, the morphology and the Al, Si dominant composition, the radial whiskers were thought to be mainly composed of mullite (alumina silicate) (Dejoie et al, 2014; Hoo et al, 2020; Kusano et al, 2008; Prostakova et al, 2019; Zhang et al, 2009). Besides, the concentrated Fe element has been discovered on the radial whiskers, as well as some dendritic flakes beside the whiskers, which is contrary to that in the Si mapping.…”

Section: Resultsmentioning

confidence: 98%

Formation mechanism of the pinholes in brown glazed stoneware from Yaozhou kiln

et al. 2021

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Pinhole is a common defect widely seen in many archeological stonewares from different kilns and periods. It is usually a sub‐millimeter pit on the glaze that was believed to be caused by the broken bubbles during the firing process. We investigated the pinholes on a porcelain sherd from Yaozhou kiln of the Song Dynasty (AD 960–1,127), surprisingly, every pinhole corresponds to a flower‐like cluster observed through the microscope. The flower‐like clusters are composed of radial mullite whiskers and ε‐Fe2O3 dendrites, and its growth mechanism were proposed after detailed microscopic and spectroscopic characterizations. The unique chemical composition around the pinholes became the breeding ground for the crystallization of flowers, whereas the crystallization process further facilitates the formation of the pinhole preventing the glaze from restoring smoothness. Our results enriched the knowledge on pinholes and revealed the interesting crystallization assisted formation mechanism, which not only related to bubble rupture but involves the crystallization dynamics as well.

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Section: Resultsmentioning

confidence: 98%

Formation mechanism of the pinholes in brown glazed stoneware from Yaozhou kiln

et al. 2021

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“…Better predictive capacity and flexibility of MQM in multicomponent systems is achieved by using pair (or quadruplet) fractions for polynomial expansion of Gibbs energy change in quasichemical reactions [53], by using composition-dependent coordination numbers [53], by combining quasichemical and Bragg-Williams random mixing contribution to the excess Gibbs energy [54], by using different geometric extrapolation methods of binary model parameters into multicomponent space [54,55], and by using quadruplet formalism for ionic liquids with several possible cations and anions [56]. Recent examples of application of MQM for different cases are provided below: slags [57][58][59][60][61], mattes and metals [40][41][42]62], slags in equilibrium with mattes [63][64][65] and/or metals [66].…”

Section: Thermodynamic Models and Databasesmentioning

confidence: 99%

Recent University Research, Implementation and Education in Support of Pyrometallurgical Lead Processing

Jak,

Shevchenko,

Shishin

et al. 2024

J. Phys.: Conf. Ser.

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The increasing chemical complexity of lead process streams encountered in industrial high temperature processing operations, as the result of declining primary resources, increased metal recycling and increased overall range of metals in modern devices has highlighted the urgent need for new predictive tools, fundamental phase equilibria and thermodynamic information and thermodynamic models to characterise the chemical behaviour of these systems. The paper examines recent progress in experimental and thermodynamic modelling research on process fundamentals, the availability of advanced, predictive computer-based tools and the implementation of the research outcomes into industrial practice. A wide range of chemical systems and phase assemblages have been studied. Some examples are taken from the current research program at PYROSEARCH, which involves the characterisation of multi-component, multi-phase gas-slag-matte-speiss-metal-solids systems with the PbO-ZnO-“Cu2O”-FeO-Fe2O3-CaO-Al2O3-MgO-SiO2-S as major and As-Sn-Sb-Bi-Ag-Au-Ni-Co-Cr-Na as minor elements with focus on systems directly relevant to lead primary and recycling pyrometallurgical processes. Examples of the application of advanced analytical techniques to fundamental and applied industrial research are also given. The implementation of new research outcomes into industrial practice depends critically on commitments by research staff as well as industry management and the availability of well-trained metallurgical engineers. We examine the current status of research implementation, university research, metallurgical engineering education and the availability of suitable educational pathways and initiatives that can be taken to increase undergraduate enrolments. Active engagement and support by industry is critical in ensuring the continuation of academic programs and advanced technical skills required by the industry.

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“…delay of the α-Al 2 3 formation has primarily kinetic reasons. As solubility of silicon in corundum is extremely low [69], Si must leave the parent metastable phase (δ/θ-Al 2 O 3 ), before this phase can transform to α-Al 2 O 3 . This process requires an additional migration or diffusion of silicon, which shifts the formation of α-Al 2 O 3 to a higher temperature.…”

Section: Stabilization Of γ -Al 2 Omentioning

confidence: 99%

Temperature-Induced Changes in the Microstructure of the Metal Melt Filters and Non-metallic Inclusions

Thümmler,

Dopita,

Motylenko

et al. 2024

Springer Series in Materials Science

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The functionalization of ceramic foam filters aims typically at the enhancement of the thermal shock resistance and the reactivity of the filters with respect to specific inclusions and impurities. For this purpose, thermodynamically metastable phases are utilized that have a strongly defective crystal structure and/or nanocrystalline character. Such phases possess frequently better or even unique properties in comparison with their thermodynamically stable counterparts. However, the stability of metastable or defect-rich phases is usually impaired by microstructural changes, which occur during the contact of these phases with the metallic melt at high temperatures and which speed up finally the degradation of the functionalized filters. In general, the first step towards the stabilization of the thermodynamically metastable and/or defect-rich phases is the understanding of their microstructure and the microstructure changes accompanying the transition to the thermodynamically stable state. In this chapter, the thermally induced microstructure changes are illustrated on the examples of selected carbon containing binders and metastable alumina phases. In order to be able to describe the crystal structure and microstructure of these compounds in more details, which is required for the targeted development of the functional filter materials, complementary methods of crystal structure and microstructure analysis like X-ray and electron diffraction, X-ray and nuclear magnetic resonance spectroscopy and electron microscopy were combined and further developed.

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Thermodynamic optimization of the Al2O3–FeO–Fe2O3–SiO2 oxide system

Cited by 30 publications

References 52 publications

Formation mechanism of the pinholes in brown glazed stoneware from Yaozhou kiln

Formation mechanism of the pinholes in brown glazed stoneware from Yaozhou kiln

Recent University Research, Implementation and Education in Support of Pyrometallurgical Lead Processing

Temperature-Induced Changes in the Microstructure of the Metal Melt Filters and Non-metallic Inclusions

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