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D. M. Pasquevich - One of the best experts on this subject based on the ideXlab platform.
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enhancing effect of Iron Chlorides on the anatase rutile transition in titanium dioxide
Journal of the American Ceramic Society, 1999Co-Authors: Fabiana C. Gennari, D. M. PasquevichAbstract:The effect of solid Fe2O3 and gaseous Iron Chlorides on the anatase-rutile phase transition was investigated in the temperature range of 750°-950°C via X-ray diffractometry and scanning electron microscopy. In both cases, Iron diffusion in the anatase lattice decreased the transition temperature and increased the anatase-rutile transformation rate, in comparison with that in TiO2 fired in air. The enhancement effect of Iron on the anatase-rutile transition is understood on the basis of oxygen-vacancy formation, which favors rutile nucleation. Solid-state Iron diffusion between the contact points of TiO2 and Fe2O3 particles and vapor mass transport through gaseous Chlorides were the primary mechanisms of Iron mass transport to the TiO2 surface in the presence of both Fe2O3 and gaseous Iron Chlorides, respectively. The transformation rate at a given reaction temperature increased in the following order of reaction conditions: pure TiO2 in air, TiO2 in the presence of Fe2O3 in air, TiO2 in the presence of Fe2O3 in chlorine, and TiO2 in the presence of gaseous Iron Chlorides.
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Enhancing Effect of Iron Chlorides on the Anatase‐Rutile Transition in Titanium Dioxide
Journal of the American Ceramic Society, 1999Co-Authors: Fabiana C. Gennari, D. M. PasquevichAbstract:The effect of solid Fe2O3 and gaseous Iron Chlorides on the anatase-rutile phase transition was investigated in the temperature range of 750°-950°C via X-ray diffractometry and scanning electron microscopy. In both cases, Iron diffusion in the anatase lattice decreased the transition temperature and increased the anatase-rutile transformation rate, in comparison with that in TiO2 fired in air. The enhancement effect of Iron on the anatase-rutile transition is understood on the basis of oxygen-vacancy formation, which favors rutile nucleation. Solid-state Iron diffusion between the contact points of TiO2 and Fe2O3 particles and vapor mass transport through gaseous Chlorides were the primary mechanisms of Iron mass transport to the TiO2 surface in the presence of both Fe2O3 and gaseous Iron Chlorides, respectively. The transformation rate at a given reaction temperature increased in the following order of reaction conditions: pure TiO2 in air, TiO2 in the presence of Fe2O3 in air, TiO2 in the presence of Fe2O3 in chlorine, and TiO2 in the presence of gaseous Iron Chlorides.
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effect of the reaction temperature on the chlorination of a fe2o3tio2c mixture
Thermochimica Acta, 1997Co-Authors: F C Gennari, Ana E Bohe, D. M. PasquevichAbstract:Abstract The intrinsic kinetics of the chlorination of an hematite-titania-carbon mixture was studied by means of scanning electron microscopy and isothermal and non-isothermal thermogravimetry between 580 and 1123 K. It was observed that various reactions take place simultaneously and that a carbon surface deactivation occurs between 733 and 820 K. The latter was attributed to chemisorption of Iron Chlorides on the carbon surface.
Toru H Okabe - One of the best experts on this subject based on the ideXlab platform.
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removal of Iron from titanium ore by selective chlorination using ticl4 under high oxygen chemical potential
International Journal of Mineral Processing, 2016Co-Authors: Jungshin Kang, Toru H OkabeAbstract:Abstract With the purpose of developing a new technology for producing high-grade titanium dioxide (TiO2), a fundamental study on the selective chlorination of low-grade titanium ore under a high oxygen chemical potential was carried out. The use of titanium tetrachloride (TiCl4) as a chlorinating agent allowed Iron to be directly removed from various types of Ti ores. In the experiments, titanium ore was first pre-oxidized under air, and then reacted with TiCl4 gas at 1100 K or 1200 K for 9 h under an Ar + 1 ppm O2, Ar + 1% O2, or Ar + 10% O2 gas flow. The Iron in the low-grade Ti ore was selectively removed as Iron Chlorides (FeClx [x = 2, 3]) in a dry form, and 98% TiO2 was obtained under certain conditions. This demonstrated that the selective chlorination of low-grade titanium ore by TiCl4 under a high oxygen chemical potential is a feasible method of producing high-grade TiO2 directly.
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Upgrading Titanium Ore Through Selective Chlorination Using Calcium Chloride
Metallurgical and Materials Transactions B, 2013Co-Authors: Jungshin Kang, Toru H OkabeAbstract:To develop a simple and effective process for upgrading low-grade titanium ore (ilmenite, mainly FeTiO_3), a new selective chlorination process based on the use of calcium chloride (CaCl_2) as the chlorine source was investigated in this study. Titanium ore and a titanium ore/CaCl_2 mixture were placed in two separate crucibles inside a gas-tight quartz tube that was then positioned in a horizontal furnace. In the experiments, the titanium ore in the two crucibles reacted with either HCl produced from CaCl_2 or CaCl_2 itself at 1100 K (827 °C), leading to the selective removal of the Iron present in the titanium ore as Iron Chlorides [FeCl_ x (l,g) ( x = 2, 3)]. Various kinds of titanium ores produced in different countries were used as feedstock, and the influence of the particle size and atmosphere on the selective chlorination was investigated. Under certain conditions, titanium dioxide (TiO_2) with purity of about 97 pct was directly obtained in a single step from titanium ore containing 51 pct TiO_2. Thus, selective chlorination is a feasible method for producing high purity titanium dioxide from low-grade titanium ore.
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recovery of titanium metal scrap by utilizing chloride wastes
Journal of Alloys and Compounds, 2008Co-Authors: Haiyan Zheng, Toru H OkabeAbstract:Abstract To develop a novel recycling process for titanium (Ti) metal scrap by utilizing chloride wastes generated from the Kroll process or any other process, some fundamental studies on the reactions between Ti and Iron Chlorides (FeCl x ) were carried out. Prior to the experiments, thermodynamic analyses on the Ti–Fe–Cl–O system were carried out to enable a discussion on the feasibility of the recycling of Ti metal scrap by FeCl x . Based on the thermodynamic analyses, a metallic Ti sample placed in a quartz tube filled with argon (Ar) gas was reacted with Iron chloride (FeCl 2 ) gas at elevated temperatures (900–1200 K), and the reaction product was analyzed. During the experiment, the formation of TiCl 4 gas was visually observed. Black residue containing metallic Fe and Ti was obtained after the experiment, and the reaction ratio of Ti reached 99% under certain experimental conditions. The reaction ratio of Ti and the reaction speed were largely dependant on the morphology of the starting material and could be improved by increasing the reaction temperature over the range of 900–1200 K. The results show that metallic Ti can be recovered in the form of TiCl 4 by utilizing FeCl 2 , and the reaction products of TiCl 4 and Fe can easily be recovered separately.
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Recycling titanium metal scraps by utilizing chloride wastes
2005Co-Authors: Haiyan Zheng, Toru H Okabe, Ryosuke Matsuoka, Komaba Meguro-kuAbstract:A novel process for recycling titanium metal scraps by utilizing the chloride wastes that is generated from the Kroll process or any other processes was investigated. Iron Chlorides (e.g., FeCl2, FeCl3) and metallic titanium (Ti) were reacted at temperatures ranging between 700 and 1300 K, and the chlorine in the Iron Chlorides was extracted in the form of TiCl4 gas. It was found that the Iron chloride wastes can be utilized as a source of chlorine for the production of TiCl4, and this process is demonstrated to be suitable for application to the treatment of titanium scraps. The behavior of chloride in the Fe-Ti-Cl-O system at 1100 K was thermodynamically analyzed. The investigation of the recycling process of the chloride wastes may be useful because it has the potential to improve the chlorine cycle in the Kroll process. If chlorine from the chloride wastes generated from titanium smelting can be efficiently recovered, the problem concerning the disposal of chloride wastes will be minimized and the loss of chlorine in the process will also decrease. The technique to recover chlorine from chloride wastes is also important, particularly when treating low-grade titanium ore, which will be an essential resource for the titanium industry in the future. This recycling process, which utilizes chloride wastes, can also be extended to other reactive metals such as rare earth metals and tantalum.
Fabiana C. Gennari - One of the best experts on this subject based on the ideXlab platform.
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enhancing effect of Iron Chlorides on the anatase rutile transition in titanium dioxide
Journal of the American Ceramic Society, 1999Co-Authors: Fabiana C. Gennari, D. M. PasquevichAbstract:The effect of solid Fe2O3 and gaseous Iron Chlorides on the anatase-rutile phase transition was investigated in the temperature range of 750°-950°C via X-ray diffractometry and scanning electron microscopy. In both cases, Iron diffusion in the anatase lattice decreased the transition temperature and increased the anatase-rutile transformation rate, in comparison with that in TiO2 fired in air. The enhancement effect of Iron on the anatase-rutile transition is understood on the basis of oxygen-vacancy formation, which favors rutile nucleation. Solid-state Iron diffusion between the contact points of TiO2 and Fe2O3 particles and vapor mass transport through gaseous Chlorides were the primary mechanisms of Iron mass transport to the TiO2 surface in the presence of both Fe2O3 and gaseous Iron Chlorides, respectively. The transformation rate at a given reaction temperature increased in the following order of reaction conditions: pure TiO2 in air, TiO2 in the presence of Fe2O3 in air, TiO2 in the presence of Fe2O3 in chlorine, and TiO2 in the presence of gaseous Iron Chlorides.
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Enhancing Effect of Iron Chlorides on the Anatase‐Rutile Transition in Titanium Dioxide
Journal of the American Ceramic Society, 1999Co-Authors: Fabiana C. Gennari, D. M. PasquevichAbstract:The effect of solid Fe2O3 and gaseous Iron Chlorides on the anatase-rutile phase transition was investigated in the temperature range of 750°-950°C via X-ray diffractometry and scanning electron microscopy. In both cases, Iron diffusion in the anatase lattice decreased the transition temperature and increased the anatase-rutile transformation rate, in comparison with that in TiO2 fired in air. The enhancement effect of Iron on the anatase-rutile transition is understood on the basis of oxygen-vacancy formation, which favors rutile nucleation. Solid-state Iron diffusion between the contact points of TiO2 and Fe2O3 particles and vapor mass transport through gaseous Chlorides were the primary mechanisms of Iron mass transport to the TiO2 surface in the presence of both Fe2O3 and gaseous Iron Chlorides, respectively. The transformation rate at a given reaction temperature increased in the following order of reaction conditions: pure TiO2 in air, TiO2 in the presence of Fe2O3 in air, TiO2 in the presence of Fe2O3 in chlorine, and TiO2 in the presence of gaseous Iron Chlorides.
Marianne Blazsó - One of the best experts on this subject based on the ideXlab platform.
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Thermal decomposition of polymers modified by catalytic effects of copper and Iron Chlorides
Journal of Analytical and Applied Pyrolysis, 1999Co-Authors: Marianne BlazsóAbstract:Abstract Effects of copper and Iron Chlorides were studied on the thermal decomposition reactions of polymers using pyrolysis-gas chromatography/mass spectrometry. Copper and Iron Chlorides found to depress the radical transfer reactions of lower probability in polypropylene and polystyrene at 500°C through the interaction of the radicals and the transition metal ions. Cu(I) and Fe(II) Chlorides enhance the production of aromatic and polyaromatic compounds from polyethylene at 1000°C promoting hydrogen elimination. Partial decomposition of the methyl ester side groups takes place in poly (methyl methacrylate) at 450°C, leading to chloromethane and carbon dioxide, when Cu(II), Fe(II) or Fe(III) chloride is present. Heterolytic cleavage of the methoxy group is presumably promoted by the electrophyl transition metal ions. Similar effect was proposed explaining the enhanced phenol evolution from phenol-formaldehyde resin, polycarbonate and epoxy resin at 500–600°C in the presence of Cu(II) and Iron Chlorides. The rupture of phenolic rings and the reduction of the phenolic hydroxyl groups leading to polyaromatic pyrolysis products from phenol-formaldehyde resin at 1000°C was reduced by Cu(II) and Iron Chlorides presumably due to a protective interaction of the phenol rings and the transition metal ions. Pyrolysis of polymers was performed also in the presence of PVC and copper or Iron. The results lead to the conclusion that the Chlorides of lower oxidation state are forming from PVC and copper or Iron when co-pyrolysed with polyethylene or phenol-formaldehyde resin.
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thermal decomposition of low density polyethylene in the presence of Iron and copper Chlorides
Journal of Analytical and Applied Pyrolysis, 1996Co-Authors: Marianne Blazsó, B ZeleiAbstract:Abstract The effects of Iron and copper Chlorides on the pyrolysis products of low-density polyethylene were studied using Py-GC/MS for the analysis of volatiles, and FT-IR spectroscopy for the pyrolysis tars. The presence of Fe(II) and Cu(I) Chlorides initiates chain scission at the early stage of polyethylene thermal decomposition, producing increased amounts of olefin bonds at 400 °C. In the presence of Iron and copper Chlorides, chlorobenzene and chloronaphthalene are formed from polyethylene at 600 °C. Considerably more chlorobenzene is produced with Cu(II) chloride than with Iron Chlorides, and the chlorination is similarly efficient also with Cu(I) chloride at 1000 °C. The amounts of aromatic volatiles are greatly increased by Cu(II) and Fe(III) Chlorides at 600 °C. However, at 1000 °C, the amounts of light aromatics are slightly reduced and the char production is favored by the presence of anhydrous Iron and copper Chlorides of a higher oxidation state.
Tomiya Kishi - One of the best experts on this subject based on the ideXlab platform.
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redox reaction in 1 ethyl 3 methylimidazolium Iron Chlorides molten salt system for battery application
Journal of Power Sources, 2002Co-Authors: Yasushi Katayama, Isamu Konishiike, Takashi Miura, Tomiya KishiAbstract:Abstract The redox reaction between divalent and trivalent Iron species in binary and ternary molten salt systems consisting of 1-ethyl-3-methylimidazolium chloride (EMICl) with Iron Chlorides, FeCl2 and FeCl3, was investigated as a candidate of the half-cell reactions of novel rechargeable redox batteries based on low temperature molten salt systems. A reversible one-electron redox reaction between divalent and trivalent Iron species was observed on a platinum electrode in EMICl–FeCl2–FeCl3 system at 130 °C. The voltammetric data indicated that divalent and trivalent Iron species were FeCl3− and FeCl4− complex anions, respectively. Combined with another proper redox couple, this molten salt system can be utilized in a rechargeable redox battery on account of its low melting temperature and reversible redox reaction.
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Redox reaction in 1-ethyl-3-methylimidazolium–Iron Chlorides molten salt system for battery application
Journal of Power Sources, 2002Co-Authors: Yasushi Katayama, Isamu Konishiike, Takashi Miura, Tomiya KishiAbstract:Abstract The redox reaction between divalent and trivalent Iron species in binary and ternary molten salt systems consisting of 1-ethyl-3-methylimidazolium chloride (EMICl) with Iron Chlorides, FeCl2 and FeCl3, was investigated as a candidate of the half-cell reactions of novel rechargeable redox batteries based on low temperature molten salt systems. A reversible one-electron redox reaction between divalent and trivalent Iron species was observed on a platinum electrode in EMICl–FeCl2–FeCl3 system at 130 °C. The voltammetric data indicated that divalent and trivalent Iron species were FeCl3− and FeCl4− complex anions, respectively. Combined with another proper redox couple, this molten salt system can be utilized in a rechargeable redox battery on account of its low melting temperature and reversible redox reaction.
