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Tarnkamol Tarvornpanich - One of the best experts on this subject based on the ideXlab platform.
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microstructural evolution in clay based ceramics i single components and binary mixtures of clay flux and quartz filler
Journal of the American Ceramic Society, 2008Co-Authors: Tarnkamol Tarvornpanich, Guilherme P Souza, W E LeeAbstract:Microstructural evolution on heating kaolinite clay, quartz, Nepheline syenite, and soda–lime–silica (SLS) glass to various temperatures to 1300°C was investigated in quenched and slowly cooled samples by XRD, thermal analysis and SEM, and by in situ XRD. In the individual components, the expected behavior was observed and in SLS glass, devitrification led to crystallization of cristobalite, quartz, devitrite, and wollastonite, which dissolved at 900°–1000°C. Significant effects of each component on microstructural evolution in the others were often observed in binary mixtures. For example, in SLS glass and quartz mixtures, devitrification of SLS glass to form cristobalite was delayed and two forms of cristobalite with different morphologies were identified. Albite and plagioclase crystallized on heating kaolin clay and SLS glass mixtures, decreasing the alumina content available for mullite formation. Melting of Nepheline syenite promoted reaction with the clay, including accelerated phase dissolution. SLS glass accelerated dissolution of Nepheline syenite and prevented leucite formation.
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microstructural evolution in clay based ceramics ii ternary and quaternary mixtures of clay flux and quartz filler
Journal of the American Ceramic Society, 2008Co-Authors: Tarnkamol Tarvornpanich, Guilherme P Souza, W E LeeAbstract:The complex microstructural evolution in mixtures of kaolinite clay, quartz, Nepheline syenite, and soda–lime–silica (SLS) glass has been revisited. Detailed descriptions of reactions leading to dense whiteware bodies backed by semi-quantitative X-ray diffraction analysis reveal that ternary mixtures containing Nepheline syenite differ from those containing SLS glass, as new crystalline phases develop inside and at the interfaces among SLS glass particles and decomposed clay and quartz. In SLS glass-fluxed mixtures, tridymite formation was hindered and cristobalite formed at ≥750°C followed by wollastonite at ≥800°C. Albite and plagioclase formed from interaction between clay and molten SLS glass above 800°C. Wollastonite was not present ≥1100°C, leaving only cristobalite in the surrounding regions. Quartz partially dissolves at temperatures ≥1000°C after interacting with molten SLS glass. In quaternary mixtures containing 6.25 wt% SLS glass and 17.25 wt% Nepheline syenite fluxes, formation of types II and III secondary mullite was more pronounced than in the fully SLS glass-fluxed mixture. The more fluid liquid from Nepheline syenite enhances the growth kinetics of mullite. The body fired at the optimum firing temperature (1100°C) has a microstructure containing primary type I and secondary types II and III mullites, remnant cristobalite, plagioclase, and partially dissolved quartz embedded in the glassy phase. Providing a roadmap for microstructural design in clay-based systems may have significant commercial impact in the emerging technology of use of waste materials in clay-based ceramics.
W E Lee - One of the best experts on this subject based on the ideXlab platform.
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microstructural evolution in clay based ceramics i single components and binary mixtures of clay flux and quartz filler
Journal of the American Ceramic Society, 2008Co-Authors: Tarnkamol Tarvornpanich, Guilherme P Souza, W E LeeAbstract:Microstructural evolution on heating kaolinite clay, quartz, Nepheline syenite, and soda–lime–silica (SLS) glass to various temperatures to 1300°C was investigated in quenched and slowly cooled samples by XRD, thermal analysis and SEM, and by in situ XRD. In the individual components, the expected behavior was observed and in SLS glass, devitrification led to crystallization of cristobalite, quartz, devitrite, and wollastonite, which dissolved at 900°–1000°C. Significant effects of each component on microstructural evolution in the others were often observed in binary mixtures. For example, in SLS glass and quartz mixtures, devitrification of SLS glass to form cristobalite was delayed and two forms of cristobalite with different morphologies were identified. Albite and plagioclase crystallized on heating kaolin clay and SLS glass mixtures, decreasing the alumina content available for mullite formation. Melting of Nepheline syenite promoted reaction with the clay, including accelerated phase dissolution. SLS glass accelerated dissolution of Nepheline syenite and prevented leucite formation.
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microstructural evolution in clay based ceramics ii ternary and quaternary mixtures of clay flux and quartz filler
Journal of the American Ceramic Society, 2008Co-Authors: Tarnkamol Tarvornpanich, Guilherme P Souza, W E LeeAbstract:The complex microstructural evolution in mixtures of kaolinite clay, quartz, Nepheline syenite, and soda–lime–silica (SLS) glass has been revisited. Detailed descriptions of reactions leading to dense whiteware bodies backed by semi-quantitative X-ray diffraction analysis reveal that ternary mixtures containing Nepheline syenite differ from those containing SLS glass, as new crystalline phases develop inside and at the interfaces among SLS glass particles and decomposed clay and quartz. In SLS glass-fluxed mixtures, tridymite formation was hindered and cristobalite formed at ≥750°C followed by wollastonite at ≥800°C. Albite and plagioclase formed from interaction between clay and molten SLS glass above 800°C. Wollastonite was not present ≥1100°C, leaving only cristobalite in the surrounding regions. Quartz partially dissolves at temperatures ≥1000°C after interacting with molten SLS glass. In quaternary mixtures containing 6.25 wt% SLS glass and 17.25 wt% Nepheline syenite fluxes, formation of types II and III secondary mullite was more pronounced than in the fully SLS glass-fluxed mixture. The more fluid liquid from Nepheline syenite enhances the growth kinetics of mullite. The body fired at the optimum firing temperature (1100°C) has a microstructure containing primary type I and secondary types II and III mullites, remnant cristobalite, plagioclase, and partially dissolved quartz embedded in the glassy phase. Providing a roadmap for microstructural design in clay-based systems may have significant commercial impact in the emerging technology of use of waste materials in clay-based ceramics.
Petras Jokubauskas - One of the best experts on this subject based on the ideXlab platform.
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Britholite Group Minerals from REE-Rich Lithologies of Keivy Alkali Granite—Nepheline Syenite Complex, Kola Peninsula, NW Russia
Minerals, 2019Co-Authors: Dmitry Zozulya, L. M. Lyalina, Ray Macdonald, Bogusław Bagiński, Yevgeny E. Savchenko, Petras JokubauskasAbstract:The Keivy alkali granite-Nepheline syenite complex, Kola Peninsula, NW Russia, contains numerous associated Zr-REE-Y-Nb occurrences and deposits, formed by a complex sequence of magmatic, late-magmatic, and post-magmatic (including pegmatitic, hydrothermal, and metasomatic) processes. The REE-rich lithologies have abundant (some of economic importance) and diverse britholite group minerals. The REE and actinides distribution in host rocks indicates that the emanating fluids were alkaline, with significant amounts of F and CO2. From chemical studies (REE and F variations) of the britholites the possible fluid compositions in different lithologies are proposed. Fluorbritholite-(Y) and britholite-(Y) from products of alkali granite (mineralized granite, pegmatite, quartzolite) formed under relatively high F activity in fluids with low CO2/H2O ratio. The highest F and moderate CO2 contents are characteristic of fluid from a mineralized Nepheline syenite, resulting in crystallization of fluorbritholite-(Ce). Britholite group minerals (mainly fluorcalciobritholite and ‘calciobritholite’) from a Nepheline syenite pegmatite formed from a fluid with composition changing from low F and high CO2 to moderate F and CO2. An extremely high F content is revealed for metasomatizing fluids emanating from alkali granitic magma and which affected the basic country rocks. The dominant substitution scheme for Keivy britholites is REE3+ + Si4+ = Ca2+ + P5+, showing the full range of ‘britholite’ and ‘calciobritholite’ compositions up to theoretical apatite.
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britholite group minerals from ree rich lithologies of keivy alkali granite Nepheline syenite complex kola peninsula nw russia
Minerals, 2019Co-Authors: Dmitry Zozulya, L. M. Lyalina, Ray Macdonald, Bogusław Bagiński, Yevgeny E. Savchenko, Petras JokubauskasAbstract:The Keivy alkali granite-Nepheline syenite complex, Kola Peninsula, NW Russia, contains numerous associated Zr-REE-Y-Nb occurrences and deposits, formed by a complex sequence of magmatic, late-magmatic, and post-magmatic (including pegmatitic, hydrothermal, and metasomatic) processes. The REE-rich lithologies have abundant (some of economic importance) and diverse britholite group minerals. The REE and actinides distribution in host rocks indicates that the emanating fluids were alkaline, with significant amounts of F and CO2. From chemical studies (REE and F variations) of the britholites the possible fluid compositions in different lithologies are proposed. Fluorbritholite-(Y) and britholite-(Y) from products of alkali granite (mineralized granite, pegmatite, quartzolite) formed under relatively high F activity in fluids with low CO2/H2O ratio. The highest F and moderate CO2 contents are characteristic of fluid from a mineralized Nepheline syenite, resulting in crystallization of fluorbritholite-(Ce). Britholite group minerals (mainly fluorcalciobritholite and ‘calciobritholite’) from a Nepheline syenite pegmatite formed from a fluid with composition changing from low F and high CO2 to moderate F and CO2. An extremely high F content is revealed for metasomatizing fluids emanating from alkali granitic magma and which affected the basic country rocks. The dominant substitution scheme for Keivy britholites is REE3+ + Si4+ = Ca2+ + P5+, showing the full range of ‘britholite’ and ‘calciobritholite’ compositions up to theoretical apatite.
A Moukhsil - One of the best experts on this subject based on the ideXlab platform.
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Silicate-carbonate liquid immiscibility: insights from the Crevier alkaline intrusion (Quebec)
Journal of Petrology, 2020Co-Authors: P.-a Groulier, F Turlin, A. S. André-mayer, D. Ohnenstetter, A Crépon, Philippe Boulvais, Marc Poujol, C. Rollion-bard, A. Zeh, A MoukhsilAbstract:This contribution explores the petrogenetic relationships between silicate and carbonatitic rocks in the Crevier Alkaline Intrusion (CAI, Québec, Canada). The CAI is located in the Proterozoic Grenville Province and is composed of a suite of undersaturated peralkaline rocks from ijolite to Nepheline syenite and carbonatites. Petrogenetic relationships between different undersaturated alkaline igneous rocks, carbonate-bearing and carbonate-free Nepheline syenite and carbonatites observed in the CAI suggest that (i) carbonate-bearing and carbonate-free silicate rocks are comagmatic with carbonatite, and that (ii) both silicate and carbonatitic liquids are fractionated from an ijolitic parental magma that has undergone liquid immiscibility. One of the observed facies is characterized by spectacular ocelli of carbonate-bearing Nepheline syenite in a matrix of carbonatite. The younger Nepheline syenite facies can be divided into two groups based on the presence or absence of magmatic carbonates. Both groups are characterized by the presence of pyrochlore-group minerals that carry the Nb-Ta mineralization.We specifically use accessory minerals such as zircon, pyrochlore and apatite to constrain the temporal and physicochemical parameters of the immiscibility process. By coupling (i) mineral textures, (ii) trace elements, (iii) Ti-in-zircon thermometry, and (iv) oxygen isotope compositions, we have traced the crystallization of zircon before, during and after the immiscibility process. The results allowed us to constrain the minimum temperature of this process at ∼815-865 °C. In addition, two magmatic populations of pyrochlore are identified through their petrographic and geochemical characteristics within the younger Nepheline syenite facies. Pyrochlore from the earlier ocelli facies of carbonate-bearing Nepheline syenite follow a Nb-Ta differentiation trend, whereas pyrochlore from the younger carbonate-free Nepheline syenite follow a more classical Nb-Ti trend. Following the complete immiscibility between the silicate and carbonatitic liquids, the fractionation between Nb and Ta stopped while a new generation of Nb-rich pyrochlore grew, displaying a more classical Nb-Ti fractionation trend and a more constant Nb/Ta ratio in the Nepheline syenite.
Isabella Lancellotti - One of the best experts on this subject based on the ideXlab platform.
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crystallisation and microstructure of Nepheline forsterite glass ceramics
Ceramics International, 2013Co-Authors: M I Martin, Fernanda Andreola, Luisa Barbieri, Isabella Lancellotti, Federica Bondioli, Ma J Rincon, M RomeroAbstract:This work presents the results of a study focused on the development of forsterite–Nepheline glass-ceramic with the use of rice husk ash (RHA) as a silica source. The glass-ceramics were produced by a sintering process of a glassy frit formulated in the MgO–Al2O3–SiO2 base system with the addition of B2O3 and Na2O to facilitate the melting and pouring processes. The crystallisation study was carried out by depicting the TTT curve (Time–Temperature–Transformation). The mineralogical characterisation of the glass-ceramic materials was carried out using the X-ray diffraction (XRD). The crystallisation activation energies were calculated by the Kissinger method. The results obtained show that devitrification of the RHA glass leads to a glass-ceramic material composed of Nepheline (Na2O·Al2O3·2SiO2) and forsterite (2MgO·SiO2). A study of the microstructure by scanning electron microscopy (SEM) allowed to establish the morphological evolution in both the shape and spatial arrangement of the Nepheline and forsterite crystals on heating.
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sintered glass ceramics and glass ceramic matrix composites from crt panel glass
Journal of the American Ceramic Society, 2005Co-Authors: Enrico Bernardo, Fernanda Andreola, Luisa Barbieri, Isabella LancellottiAbstract:Sintering with simultaneous crystallization of powdered glass represents an interesting processing route for glass–ceramics, especially originating from wastes. Highly dense glass–ceramic samples may be obtained from a simple and short treatment at a relatively low temperature. In addition, glass–ceramic matrix composites may be obtained by mixing glass with suitable reinforcements. In this work sintered Nepheline glass–ceramics, based on panel glass from cathode ray tubes, are illustrated. A limited addition of Al2O3 platelets caused a significant improvement in the mechanical properties (elastic modulus, bending strength, microhardness, fracture toughness), already remarkable for the un-reinforced glass–ceramic, compared with traditional Nepheline glass–ceramics.
