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Thermal Dechlorination Kinetics of Rare Earth Oxychlorides

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Journal of Rare Earths 2007年第S1期25卷 8-12页

作者： Hee-Chul Yang Yong-Zun Cho Hee-Chul Eun Eung-Ho Kim In-Tae Kim advanced fuel cycle process development Group Korea Atomic Energy ResearchInstituteDaejeon 305-353 Korea

The kinetics of a thermal dechlorination and oxidation of NdOCl and GdOCl were investigated by using a non-isothermal thermogravimetric analysis under various oxygen partial pressures. The conversions of NdOCl and GdOCl into each of their stable oxides (Nd2O3 and Gd2O3) appeared to be an oxygen-dependent endothermic and one-step reaction. The observed activation energy for the conversions of NdOCl and GdOCl were determined as 228.3±6.1 kJ·mole-1 and 137.7±4.1 kJ·mole-1, respectively. The conversions of NdOCl and GdOCl into each of their stable oxides (Nd2O3 and Gd2O3) could be described by a power law (g(α)=α3/2) and a linear-contracting boundary reaction (g(α)=α), respectively.

关键词： oxychloride dechlorination oxidation high temperature rare earths

Synthesis and microstructure characterization of tetragonal Zr1–xTixO2 （x = 0–1） solid solutions

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Journal of Materials Science & Technology 2019年第9期35卷 1966-1976页

作者： Linggen Kong Inna Karatchevtseva Hanliang Zhu Meng Jun Qin Zaynab Aly Nuclear fuel cycle Research Australian Nuclear Science and Technology Organisation

Oxide powders of Zr1_xTixO2(x=0-1)solid solutions with micron-sized particles were synthesized via a solution combustion *** synthesis process and Zr/Ti molar ratio were optimized to produce powders with the tetragonal crystal structure.X-ray diffraction,Raman spectroscopy and transmission electron spectroscopy results confirm that a full crystallization microstructure with the single tetragonal phase is obtained after calcination at 600℃while maintaining the crystallite size67 mol%exhibit a tetragonal crystal structure and the embedding Ti in ZrO2 improves the structure *** nitrogen sorption results indicate that the powders possess mesoporous morphology with medium specific surface areas(~10-50 m^2/g).Chemical stability tests show that these powders are relatively stable with negligible removal of titanium and zirconium after elution by 0.5 mol/L *** functional theory was used to calculate the most stable structure with low energy for the selected composition.

关键词： Tetragonal Titanium zirconate Solid solution Chemical synthesis

Maximizing biomass utilization: An integrated strategy for coproducing multiple chemicals

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Journal of Energy Chemistry 2025年第1期100卷 180-191页

作者： Byeongchan Ahn Sua Jo Jonggeol Na J.Jay Liu Young-Ju Kim Wangyun Won Department of Chemical and Biological Engineering Korea University Department of Chemical Engineering (Integrated process) Kyung Hee University Department of Chemical Engineering and Materials Science Ewha Womans University Department of Chemical Engineering Pukyong National University Resources Engineering Plant Research Department Korea Institute of Geoscience and Mineral Resources

Lignocellulosic biomass is one of the viable solutions to alleviate the global warming. However, the limited utilization of biomass majorly focused on cellulose and hemicellulose restricts the economic and environmental feasibilities. To cope with this issue, we proposed an integrated process of co-producing 1,6-hexanediol（1,6-HDO） with tetrahydrofuran and adipic acid from biomass, referred to as Strategy A. To compare the impacts of lignin upgrading and feedstock, Strategy B, which co-produces tetrahydrofuran alone, and Strategy C, which is the traditional route to produce 1,6-HDO from fossil fuels, were used. Heat networks are also designed to reduce operating costs and indirect carbon emissions due to energy consumption, saving 87% and 83% of the heat and cooling requirements, respectively, in Strategy A. The market competitiveness of Strategy A was evaluated by determining the minimum selling price through techno-economic analysis, and sustainability was thoroughly investigated by quantifying the environmental impacts through both midpoint and endpoint life-cycle assessments（LCAs）.Strategy A was found to be the most favorable both economically（USRDSCHARDOLLAR3,402/ton） and environmentally（-26.9 kg CO2eq.）. This indicates that lignin valorization is not only economically but also environmentally preferred. Finally, changes in economic and environmental feasibilities depending on economic, process, and environmental parameters were investigated using sensitivity and uncertainty analyses. The results of these analyses provide valuable insight into bio-based chemical production.

关键词： Carbon capture and utilization

Preconcentration of rare earth elements from Iranian monazite ore by spiral separator using multi-response optimization method

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International Journal of Mining Science and Technology 2014年第1期24卷 117-121页

作者： Khanchi Ali Reza Sedighi Hassan Ansar Sheida Fasihi Javad Nuclear fuel cycle Research School Nuclear Science and Technology Research InstituteAEOI

The present work dealt with the preconcentration of rare earth elements in Saghand ore(Yazd province,Iran)which was achieved by Humphrey spiral using orthogonal optimization method after scrubbing the sample at 45%solid pulp density for 30 *** pulp was diluted and was fed to a Humphrey spiral for *** process parameters considered were feed size,feed solids and feed rate,and Taguchi’s L9(34)orthogonal array(OA)was selected for optimization of the *** results show that the feed rate and feed size were more significant than the other operation parameters of the *** was also found that under optimal conditions,the concentrate grade of rare earth elements increased from2860 10 6to 6050 10 6and recovery reached to 58%.

关键词： Monazite Taguchi method Spiral Preconcentration Optimization

Kinetics of gadolinium extraction with D2EHPA and Cyanex301 using single drop column

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Rare Metals 2016年第6期35卷 487-494页

作者： Rezvan Torkaman Meisam Torab-Mostaedi Jaber Safdari Mohammad Ali Moosavian School of Chemical Engineering College of EngineeringUniversity of Tehran Nuclear fuel cycle Research School Nuclear Science and Technology Research Institute

The extraction kinetics of Gd（III） from the nitric acid medium using bis（2,4,4-trimethylpentyl） dithio- phosphinic acid （Cyanex301） and 2-ethylhexyl phosphoric acid （D2EHPA） in kerosene solution were measured by the single drop technique. The influences of hydrogen ion concentration, gadolinium ion concentration, extractant concentration, column height, and nozzle diameter on the extraction rate were investigated. The forward rate equations for the gadolinium extraction with D2EHPA and Cyanex301 were obtained. Based on the experimental results, the forward extraction rate constant was calculated. With the increase of D2EHPA or Cyanex301 concentration, the drop rising diameter and the value of interfacial tension decrease in the studied system, which shows that D2EHPA or Cyanex301 has interfacial activity as a kind of surfactant. Also, the droplet diameter and interfacial tension decrease with the increase of aqueous solution acidity. The experimental results show that the D2EHPA extractant provides faster extraction rate in comparison with Cyanex301 extractant, and it would be useful in industrial continuous extraction process.

关键词： Reaction kinetics Solvent extraction Single drop column Gadolinium Rare earths

Coupling system application in photocatalytic degradation of methylorange by TiO_2, TiO_2/SiO_2 and TiO_2/SiO_2/Ag

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Rare Metals 2015年第12期34卷 851-858页

作者： Hossein Ghasemi Mobtaker Seyed Javad Ahmadi Shahram Moradi Dehaghi Taher Yousefi Nuclear fuel cycle Research School Nuclear Science and Technology Research Institute Faculty of Chemistry Tehran North Branch Islamic Azad University

Three different photocatalysts including TiO2, TiO2/SiO2 and TiO2/SiO2/Ag were synthesized via sol–gel growth method, in which colloidal silica was used as Si source, titanium tetra iso-propoxide (TTiP) as titanium source, Ag+ as dopant ion and hydroxypropyl cellulose (HPC) as dispersant. The purpose was to study the enhancement of photocatalytic activity of TiO2 by deposition on SiO2 colloids and also doping with Ag ion. The catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FT-IR) and Brunauer–Emmett–Teller (BET) methods. It is confirmed that the major phase in all catalysts is anatase. Photocatalytic activity was studied in various conditions for degradation of methylorange (as a model pollutant) to evaluate the effect of some parameters on degradation efficiency. Studying the degradation process in various pH values reveals that the degradation is more efficient in acidic solution than alkaline condition. Coupling the photocatalytic process with some fields called electro-photochemical (EP), magnetic-photochemical (MP) and ultrasonic-photochemical (UP) was studied at two pH values which were compared with photochemical (P) alone. It is concluded that in most cases, the EP is the best coupled system and has the maximum efficiency. Liquid chromatography–mass spectrometry (LC–MS) analysis was used to check the complete decomposition of methylorange at the end of process.

关键词： Doping Electro-photochemical Magnetic-photochemical Ultrasonic-photochemical Sol–gel

Conversion of CO into CO_(2) by high active and stable PdNi nanoparticles supported on a metal-organic framework

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Frontiers of Chemical Science and Engineering 2022年第7期16卷 1139-1148页

作者： Fateme Abbasi Javad Karimi-Sabet Zeinab Abbasi Cyrus Ghotbi Department of Petroleum and Chemical Engineering Sharif University of TechnologyTehranIran Nuclear fuel cycle Research School Nuclear Science and Technology Research InstituteTehranIran

The solubility of Pd(NO_(3))_(2) in water is moderate whereas it is completely soluble in diluted HNO_(3) solution. Pd/MIL-101(Cr) and Pd/MIL-101-NH_(2)(Cr) were synthesized by aqueous solution of Pd(NO_(3))_(2) and Pd(NO_(3))_(2) solution in dilute HNO_(3) and used for CO oxidation reaction. The catalysts synthesized with Pd(NO_(3))_(2) solution in dilute HNO_(3) showed lower activity. The aqueous solution of Pd(NO_(3))_(2) was used for synthesis of mono-metal Ni, Pd and bimetallic PdNi nanoparticles with various molar ratios supported on MOF. Pd_(70)Ni_(30)/MIL-101(Cr) catalyst showed higher activity than monometallic counterparts and Pd+ Ni physical mixture due to the strong synergistic effect of PdNi nanoparticles, high distribution of PdNi nanoparticles, and lower dissociation and desorption barriers. Comparison of the catalysts synthesized by MIL-101(Cr) and MIL-101-NH_(2)(Cr) as the supports of metals showed that Pd/MIL-101-NH_(2)(Cr) outperforms Pd/MIL-101-(Cr) because of the higher electron density of Pd resulting from the electron donor ability of the NH_(2) functional group. However, the same activities were observed for Pd_(70)Ni_(30)/MIL-101(Cr) and Pd_(70)Ni_(30)/MIL-101-NH_(2)(Cr), which is due to a less uniform distribution of Pd nanoparticles in Pd_(70)Ni_(30)/MIL-101-NH_(2)(Cr) originated from amorphization of MIL-101-NH_(2)(Cr) structure during the reduction process. In contrast, Pd_(70)Ni_(30)/MIL-101(Cr) revealed the stable structure and activity during reduction and CO oxidation for a long time.

关键词： CO oxidation heterogeneous catalysis metal-organic framework NH_(2)functional group PdNi

Accelerated life-time test of MEA durability under vehicle operating conditions in PEM fuel cell

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Frontiers in Energy 2017年第3期11卷 326-333页

作者： Tian TIAN Jianjun TANG Wei GUO Mu PAN State Key Laboratory of advanced Technology for Materials Synthesis and processing Hubei Provincical Key Laboratory of Fuel Cell Wuhan University of Technology Wuhan 430070 China

In this paper, a novel accelerated test method was proposed to analyze the durability of MEA, considering the actual operation of the fuel cell vehicle. The proposed method includes 7 working conditions： open circuit voltage （OCV）, idling, rated output, overload, idling-rated cycle, idling-overload cycle, and OCV-idling cycle. The experimental results indicate that the proposed method can effectively destroy the MEA in a short time （165 h）. Moreover, the degradation mechanism of MEA was analyzed by measuring the polarization curve, CV, SEM and TEM. This paper may provide a new research direction for improving the durability of fuel cell.

关键词： polymer electrolyte membrane fuel cell accelerated life-time test load cycling test durability

Formation of intermetallic compound at interface between rare earth elements and ferritic-martensitic steel by fuel cladding chemical interaction

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Journal of Rare Earths 2012年第6期30卷 599-603页

作者： Jun Hwan Kim Byoung Oon Lee Chan Bock Lee Seung Hyun Jee Young Soo Yoon advanced fuel development Division Korea Atomic Energy Research InstituteP.O.Box 105YuseongDaejeon305-600Republic of Korea Department of Mate-rials Science and Engineering Yonsei University134 Sinchon DongSeoul120-749Republic of Korea

The intermetallic compounds formation at interface between rare earth elements and clad material were investigated to demonstrate the effects of rare earth elements on fuel-cladding chemical interaction （FCCI） behavior. Mischmetal （70Ce-30La） and Nd were prepared as rare earth elements. Diffusion couple testing was performed on the rare earth elements and cladding （9Cr2W steel） near the operation temperature of （sodium-cooled fast reactor） SFR fuel. The performance of a diffusion barrier consisting of Zr and V metallic foil against the rare earth elements was also evaluated. Our results showed that Ce and Nd in the rare earth elements and Fe in the clad material interdiffused and reacted to form intermetallic species according to the parabolic rate law, describing the migration of the rare earth element. The diffusion of Fe limited the reaction progress such that the entire process was governed by the cubic rate law. Rare earth materials could be used as a surrogate for high burnup metallic fuels, and the performance of the barrier material was demonstrated to be effective.

关键词： intermetallic compound sodium-cooled fast reactor (SFR) metallic fuel fuel-cladding chemical interaction (FCCI) rare earths Barrier