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Dongbin Wang - One of the best experts on this subject based on the ideXlab platform.
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effect of andalusite and zircon on the performances of cordierite Spodumene composite ceramics for solar heat transmission pipeline
Ceramics International, 2016Co-Authors: Jianfeng Wu, Yinfeng Zhang, Cheng Hu, Xiaohong Xu, Chenglong Lu, Dongbin WangAbstract:Abstract Cordierite-Spodumene composite ceramics used for solar heat transmission pipeline were prepared via pressureless sintering from kaolin, talc, γ-Al 2 O 3 and Spodumene. Effects of andalusite and zircon on densification, mechanical properties, phase composition, microstructure and thermal shock resistance of the composite ceramics were investigated. The results showed that andalusite and zircon additives effectively affected mechanical strength and thermal stability of the composite ceramics. Expecially, sample B5 with 15 wt% zircon additive sintered at 1360 °C achieved the highest bending strength and thermal shock resistance. The bending strengths of the sample before and after 30 thermal shock cycles (wind cooling from 1100 °C to room temperature) were 100.17 MPa and 101.90 MPa, respectively. XRD analysis indicated that the main phases of the sample before 30 thermal shock cycles were α-cordierite, spinel, corundum, α-quartz and zirconium silicate, while β-Spodumene grains generated after thermal shock. SEM micrographs illustrated that the existence of zirconium silicate and β-Spodumene at the grain boundaries after 30 thermal shock cycles endowed the composite ceramics with a high residual strength. It is believed that the cordierite-Spodumene composite ceramics can be a potential material to apply in the field of solar thermal transmission pipeline.
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Preparation and thermal shock resistance of cordierite-Spodumene composite ceramics for solar heat transmission pipeline
Ceramics International, 2016Co-Authors: Yinfeng Zhang, Dongbin WangAbstract:Abstract Cordierite-Spodumene composite ceramics with 5, 10, 15 wt% Spodumene used for solar heat transmission pipeline were in-situ prepared via pressureless sintering from kaolin, talc, γ-Al 2 O 3 and Spodumene. Effects of Spodumene on densification, mechanical properties, thermal shock resistance, phase composition and microstructure of the composite ceramics were investigated. The results showed that Spodumene used as flux material decreased the sintering temperature greatly by 40–80 °C, and improved densification and mechanical properties of the composite ceramics. Especially, sample A3 with 10 wt% Spodumene additive sintered at 1380 °C exhibited the best bending strength and thermal shock resistance. The bending strengths of A3 before and after 30 thermal shock cycles (wind cooling from 1100 °C to room temperature) were 102.88 MPa and 96.29 MPa, respectively. XRD analysis indicated that the main phases of the samples before 30 thermal shock cycles were α-cordierite, α-quartz and MgAl 2 O 4 , and plenty of β-Spodumene appeared after thermal shock. SEM micrographs illustrated that the submicron β-Spodumene grains generated at the grain boundaries after thermal shock improved the thermal shock resistance. It is believed that the cordierite-Spodumene composite ceramics can be a promising candidate material for heat transmission pipeline in the solar thermal power generation.
Yinfeng Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of andalusite and zircon on the performances of cordierite Spodumene composite ceramics for solar heat transmission pipeline
Ceramics International, 2016Co-Authors: Jianfeng Wu, Yinfeng Zhang, Cheng Hu, Xiaohong Xu, Chenglong Lu, Dongbin WangAbstract:Abstract Cordierite-Spodumene composite ceramics used for solar heat transmission pipeline were prepared via pressureless sintering from kaolin, talc, γ-Al 2 O 3 and Spodumene. Effects of andalusite and zircon on densification, mechanical properties, phase composition, microstructure and thermal shock resistance of the composite ceramics were investigated. The results showed that andalusite and zircon additives effectively affected mechanical strength and thermal stability of the composite ceramics. Expecially, sample B5 with 15 wt% zircon additive sintered at 1360 °C achieved the highest bending strength and thermal shock resistance. The bending strengths of the sample before and after 30 thermal shock cycles (wind cooling from 1100 °C to room temperature) were 100.17 MPa and 101.90 MPa, respectively. XRD analysis indicated that the main phases of the sample before 30 thermal shock cycles were α-cordierite, spinel, corundum, α-quartz and zirconium silicate, while β-Spodumene grains generated after thermal shock. SEM micrographs illustrated that the existence of zirconium silicate and β-Spodumene at the grain boundaries after 30 thermal shock cycles endowed the composite ceramics with a high residual strength. It is believed that the cordierite-Spodumene composite ceramics can be a potential material to apply in the field of solar thermal transmission pipeline.
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Preparation and thermal shock resistance of cordierite-Spodumene composite ceramics for solar heat transmission pipeline
Ceramics International, 2016Co-Authors: Yinfeng Zhang, Dongbin WangAbstract:Abstract Cordierite-Spodumene composite ceramics with 5, 10, 15 wt% Spodumene used for solar heat transmission pipeline were in-situ prepared via pressureless sintering from kaolin, talc, γ-Al 2 O 3 and Spodumene. Effects of Spodumene on densification, mechanical properties, thermal shock resistance, phase composition and microstructure of the composite ceramics were investigated. The results showed that Spodumene used as flux material decreased the sintering temperature greatly by 40–80 °C, and improved densification and mechanical properties of the composite ceramics. Especially, sample A3 with 10 wt% Spodumene additive sintered at 1380 °C exhibited the best bending strength and thermal shock resistance. The bending strengths of A3 before and after 30 thermal shock cycles (wind cooling from 1100 °C to room temperature) were 102.88 MPa and 96.29 MPa, respectively. XRD analysis indicated that the main phases of the samples before 30 thermal shock cycles were α-cordierite, α-quartz and MgAl 2 O 4 , and plenty of β-Spodumene appeared after thermal shock. SEM micrographs illustrated that the submicron β-Spodumene grains generated at the grain boundaries after thermal shock improved the thermal shock resistance. It is believed that the cordierite-Spodumene composite ceramics can be a promising candidate material for heat transmission pipeline in the solar thermal power generation.
Jianfeng Wu - One of the best experts on this subject based on the ideXlab platform.
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effect of andalusite and zircon on the performances of cordierite Spodumene composite ceramics for solar heat transmission pipeline
Ceramics International, 2016Co-Authors: Jianfeng Wu, Yinfeng Zhang, Cheng Hu, Xiaohong Xu, Chenglong Lu, Dongbin WangAbstract:Abstract Cordierite-Spodumene composite ceramics used for solar heat transmission pipeline were prepared via pressureless sintering from kaolin, talc, γ-Al 2 O 3 and Spodumene. Effects of andalusite and zircon on densification, mechanical properties, phase composition, microstructure and thermal shock resistance of the composite ceramics were investigated. The results showed that andalusite and zircon additives effectively affected mechanical strength and thermal stability of the composite ceramics. Expecially, sample B5 with 15 wt% zircon additive sintered at 1360 °C achieved the highest bending strength and thermal shock resistance. The bending strengths of the sample before and after 30 thermal shock cycles (wind cooling from 1100 °C to room temperature) were 100.17 MPa and 101.90 MPa, respectively. XRD analysis indicated that the main phases of the sample before 30 thermal shock cycles were α-cordierite, spinel, corundum, α-quartz and zirconium silicate, while β-Spodumene grains generated after thermal shock. SEM micrographs illustrated that the existence of zirconium silicate and β-Spodumene at the grain boundaries after 30 thermal shock cycles endowed the composite ceramics with a high residual strength. It is believed that the cordierite-Spodumene composite ceramics can be a potential material to apply in the field of solar thermal transmission pipeline.
Yuhua Wang - One of the best experts on this subject based on the ideXlab platform.
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Surface chemistry features of Spodumene with isomorphous substitution
Minerals Engineering, 2020Co-Authors: Guangli Zhu, Yuhua Wang, Xuming Wang, J D Miller, Yijun Cao, Xiayu ZhengAbstract:Abstract Spodumene is an important strategic mineral resource for production of lithium. Froth flotation technology is a major method for recovery of Spodumene. Surface chemistry features of minerals have significant effects on flotation performance. Natural Spodumene crystals have lattice defects, including isomorphous substitution of Fe, Mn, and Cr. Such substitution will affect surface features, such as hydrophobicity of minerals and collector adsorption on mineral surfaces. In this regard, the influences of lattice substitution on Spodumene surface properties were studied with respect to wetting characteristics and collector adsorption using micro-flotation experiments, contact angle measurements, Fourier-transform infrared spectroscopy (FTIR) analysis, molecular dynamics (MD) simulations, and density functional theory (DFT) calculations. Micro-flotation experiments, FTIR analysis, and contact angle results showed that higher Fe contents favored for the oleate adsorption on Spodumene surface. Contact angle measurement and MD simulation results revealed that Spodumene surfaces with or without substitution were naturally hydrophilic, but the interfacial water structures were expected to be different with various substitutions. Therefore, the interfacial water structure was further analyzed for a better understanding of the wetting of surface. DFT calculations showed that the surfaces with substitution were more in favor of oleate adsorption than the surface without substitution. The surface with Mn substituting for Si was more favorable for the oleate adsorption. It seems that the metal ion sites at surfaces contribute to different interfacial water structures, and lattice substitution plays a significant role in the adsorption state of NaOL.
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Effects of grinding environment and lattice impurities on Spodumene flotation
Transactions of Nonferrous Metals Society of China, 2019Co-Authors: Guangli Zhu, Yuhua Wang, Yuehao Zhao, Xuming Wang, J D Miller, Xiayu Zheng, Lu Dongfang, Haitao ZhengAbstract:Abstract The effect of grinding on the Spodumene flotation was investigated. The flotation response of Spodumene ground by different mills was different, due to the variation of metal ions on Spodumene surfaces caused by grinding environments and/or impurities. The samples were subjected to acid pickling treatment to remove most of the metal ions from the surfaces, and then all samples showed the same poor flotation response, which confirmed the significance of surface metal ions. Metal ion impurities may come from both grinding environments and lattice substitutions in Spodumene. Density functional theory (DFT) calculation revealed that Fe and Ca could exist as lattice substitutions on the Spodumene surface while Mg substitution is unlikely to occur. Furthermore, Fe is considered to be active site for the absorption of sodium oleate on the Spodumene surface. Morphology analysis showed differences in particle size and shape for samples ground by different mills, resulting in different amounts of exposed surfaces. The particle size, cleavage characteristics caused by grinding environments, and metal ion impurities originated from grinding and isomorphous substitutions, play significant roles in the chemisorption of collector on the Spodumene surface.
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Wetting characteristics of Spodumene surfaces as influenced by collector adsorption
Minerals Engineering, 2019Co-Authors: Guangli Zhu, Yuhua Wang, Xuming Wang, J D MillerAbstract:Abstract The selective flotation separation of Spodumene from other aluminosilicate minerals remains a challenging problem in flotation chemistry, and the surface chemistry features are of fundamental importance. In this study, the interfacial chemistry features, particularly the wetting characteristics of selected Spodumene surfaces (1 1 0, 0 0 1, 0 1 0, and 1 0 0 crystal surfaces), in the absence and presence of collectors, were studied by water contact angle and bubble attachment measurements, molecular dynamics (MD) simulation, and sum-frequency vibrational spectroscopy (SFVS). The experimental results revealed the interfacial water structure at Spodumene surfaces. Contact angle, bubble attachment measurements, and MD simulation results showed that the four Spodumene surfaces were naturally hydrophilic, whereas in the presence of collectors, preferential adsorption of sodium oleate on the (1 0 0) and (1 1 0) surfaces was found to create a hydrophobic surface state. Detailed analysis of the interfacial water structure was conducted in order to understand the wetting characteristics at the molecular level, and SFVS was used to study the state of collectors at selected surfaces. The MD simulation and SFVS results revealed that the natural state of the surfaces contributes to the distinct interfacial water structure and the adsorption state of collectors. It seems that unsaturated Al sites at the Spodumene surface and their spatial locations account for chemisorption of sodium oleate, while electrostatic attraction appears to be the main driving force for dodecylamine adsorption.
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states of coadsorption for oleate and dodecylamine at selected Spodumene surfaces
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2018Co-Authors: Yuhua Wang, Xuming Wang, Fushun Yu, J D MillerAbstract:Abstract In our latest study, it was reported that the effective flotation separation of Spodumene from feldspar could be achieved using a mixture of the anionic collector, sodium oleate (NaOL) and the cationic collector, dodecylamine hydrochloride (DDA). This study is an extension of the previous work to provide further details of the coadsorption and association states for the NaOL/DDA collector mixture at selected Spodumene and feldspar surfaces using Fourier transform infrared spectroscopy (FTIR), sum frequency vibrational spectroscopy (SFVS), density functional theory (DFT) calculations, contact angle measurements, and micro-flotation experiments. An important finding from the results was significantly improved collector adsorption at the Spodumene (001) surface with small addition of DDA which was responsible for improved Spodumene flotation using NaOL as the dominating collector. In the absence of DDA, oleate adsorbed as a well packed monolayer at the Spodumene (110) surface, while poor adsorption of oleate with gauche defects was observed at the Spodumene and feldspar (001) surfaces. A certain amount of DDA significantly enhanced the collector adsorption at the Spodumene (001) surface, but had little or no effect on adsorption at the Spodumene (110) surface and the feldspar (001) surface. Under these circumstances, an excellent separation of Spodumene from feldspar can be achieved, as confirmed by contact angle and micro-flotation results. On the other hand, good adsorption and ordered structures of DDA and its dominative mixtures were observed at all selected surfaces. DFT calculation indicates that the association of DDA ion with oleate is preferred and accounts for the variations in collector adsorption states at these selected surfaces.
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Surface dissolution of Spodumene and its role in the flotation concentration of a Spodumene ore
Minerals Engineering, 2018Co-Authors: Yuhua Wang, Guangli Zhu, Liguang Wang, Yuehao Zhao, Lei Zhang, Haitao ZhengAbstract:Abstract The effects of sodium hydroxide and sodium carbonate on the flotation of Spodumene were investigated by flotation tests, XPS and SEM measurments and thermodynamic analysis. A collector YOA (a mixture of 90% oleic acid and 10% dodecyl amine) was used in the flotation. It was found that sodium hydroxide showed an activation effect whereas sodium carbonate showed a depression effect on the flotation of Spodumene. This difference in flotation performance was consistent with the measured contact angles of Spodumene treated in sodium hydroxide and sodium carbonate solutions, respectively. XPS results indicated that the pretreatment of Spodumene surface by sodium hydroxide gave larger relative contents of Al and Li on Spodumene surface than that of sodium carbonate, and the scanning electron microscopy images showed rougher surfaces indicating leaching of the mineral surface. The spontaneity of possible reactions associated with the surface dissolution of Spodumene in alkaline solutions was also examined, and the results could largely account for the observed difference in surface dissolution of Spodumene in sodium hydroxide and sodium carbonate solutions.
S.o. Souza - One of the best experts on this subject based on the ideXlab platform.
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Synthetic Spodumene polycrystals as a TL dosimetric material
Radiation Measurements, 2008Co-Authors: G.m. Ferraz, J.r.b. Paião, S. Watanabe, S.o. SouzaAbstract:Synthetic beta-Spodumene polycrystals were produced by a devitrification method, undoped and doped with controlled concentration of the Ce3+ or Mn2+ impurities. The TL properties of these polycrystals and of a colourless natural Spodumene were investigated. Some dosimetric properties of them were also discussed. The dopants do not affect the TL peak position with respect a pure beta-Spodumene sample but the intensity of the TL peaks at 180 and 280 degrees C is improved in the Ce-doped one. The Ce3+ ions do not participate in the TL light emission; on the other hand, the presence of Mn2+ ions cause an emission band around 600-650 nm in the TL light emission spectrum. The emission around 400 nm appears in the TL emission spectrum of all the samples and it is believed to correspond to aluminium centre ([AlO4/hole](0)) recombination with an electron. The more sensitive samples to gamma-radiation are the colourless natural Spodumene and the Ce-doped synthetic Spodumene, respectively. The colourless natural Spodumene crystal shows a TL peak at 180 degrees C suitable for dosimetry, while for Ce-doped beta-Spodumene sample the TL peaks at 180 and 280 degrees C can be used. No fading of the TL emission was observed for Ce-doped beta-Spodumene sample up to 80 days after irradiation. (C) 2007 Elsevier Ltd. All rights reserved
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Electronic and optical properties of Spodumene gemstone : A theoretical study
Optical Materials, 2008Co-Authors: A.f. De Lima, S.o. Souza, M.v. LalicAbstract:Abstract The Spodumene (LiAlSi2O6) is a natural silicate with monoclinic structure, interesting for a jewel industry and possible application as a scintillator. In this paper we present the electronic structure and some of the basic optical properties of the pure Spodumene crystal, as calculated by the first-principles, density functional based, full potential linear augmented plane wave method.
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Synthetic Spodumene polycrystals as a TL dosimetric material
Radiation Measurements, 2007Co-Authors: G.m. Ferraz, J.r.b. Paião, S. Watanabe, S.o. SouzaAbstract:Abstract Synthetic β -Spodumene polycrystals were produced by a devitrification method, undoped and doped with controlled concentration of the Ce 3 + or Mn 2 + impurities. The TL properties of these polycrystals and of a colourless natural Spodumene were investigated. Some dosimetric properties of them were also discussed. The dopants do not affect the TL peak position with respect a pure β -Spodumene sample but the intensity of the TL peaks at 180 and 280 ∘ C is improved in the Ce-doped one. The Ce 3 + ions do not participate in the TL light emission; on the other hand, the presence of Mn 2 + ions cause an emission band around 600–650 nm in the TL light emission spectrum. The emission around 400 nm appears in the TL emission spectrum of all the samples and it is believed to correspond to aluminium centre ([AlO 4 /hole] 0 ) recombination with an electron. The more sensitive samples to γ -radiation are the colourless natural Spodumene and the Ce-doped synthetic Spodumene, respectively. The colourless natural Spodumene crystal shows a TL peak at 180 ∘ C suitable for dosimetry, while for Ce-doped β -Spodumene sample the TL peaks at 180 and 280 ∘ C can be used. No fading of the TL emission was observed for Ce-doped β -Spodumene sample up to 80 days after irradiation.
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Thermoluminescent Mechanism in Lilac Spodumene
Acta Physica Polonica A, 2007Co-Authors: S.o. Souza, A.f. De Lima, S. Watanabe, M.v. LalicAbstract:In the present work the thermoluminescence of a lilac α-Spodumene (LiAlSi2O6), a natural mineral from Brazil, was investigated. Toward this aim the gamma irradiation, as well as several heating processes were carried out. The sample presented a glow curve with various thermoluminescence peaks. Emission spectrum showed only one prominent band at 610 nm, which indicates the existence of only one recombination center despite the several thermoluminescence centers exhibited, due to intrinsic defects. Using correlation between thermoluminescence and optical absorption techniques we discuss the effects of gamma radiation and annealing in the lilac Spodumene, and conclude that an annealing at about 230◦C can be applied to natural lilac Spodumene gems used in jewelry for increment of its lilac color.
