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Diffusion and reaction mechanism of limestone and quartz in fluxed iron ore pellet roasting process

International Journal of Minerals,metallurgy and Materials 2024年第3期31卷 485-497页

作者： Yufeng Guo Jinlai Zhang Shuai Wang Jianjun Fan Haokun Li Feng Chen Kuo Liu Lingzhi Yang School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China Technology Center Taiyuan Iron Steel(Group)Co.Ltd.(TISCO)Taiyuan 030003China

The increase to the proportion of fluxed pellets in the blast furnace burden is a useful way to reduce the carbon emissions in the ironmaking *** this study,the interaction between calcium carbonate and iron ore powder and the mineralization mechanism of fluxed iron ore pellet in the roasting process were investigated through diffusion couple *** electron microscopy with energy dispersive spectroscopy was used to study the elements’diffusion and phase transformation during the roasting *** results indicated that limestone decomposed into calcium oxide,and magnetite was oxidized to hematite at the early stage of *** the increase in roasting temperature,the diffusion rate of Fe and Ca was obviously accelerated,while the diffusion rate of Si was relatively *** order of magnitude of interdiffusion coefficient of Fe_(2)O_(3)-CaO diffusion couple was 10^(−10) m^(2)·s^(−1) at a roasting temperature of 1200℃for 9 ***_(2)Fe_(2)O_(5) was the initial product in the Fe_(2)O_(3)-CaO-SiO_(2) diffusion interface,and then Ca_(2)Fe_(2)O_(5) continued to react with Fe_(2)O_(3) to form CaFe_(2)O_(4).With the expansion of the diffusion region,the sillico-ferrite of calcium liquid phase was produced due to the melting of SiO_(2) into CaFe_(2)O_(4),which can strengthen the consolidation of fluxed ***,andradite would be formed around a small part of quartz particles,which is also conducive to the consolidation of fluxed *** addition,the principle diagram of limestone and quartz diffusion reaction in the process of fluxed pellet roasting was discussed.

关键词： fluxed iron ore pellet limestone hematite quartz diffusion reaction

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Magnetic properties and magnetocaloric effects in Eu(Ti,Nb,Mn)O_(3) perovskites

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Journal of Rare Earths 2024年第8期42卷 1560-1567,I0006页

作者： Junfeng Wang Huicai Xie Quanyi Liu Zhihong Hao Zhaojun Mo Qi Fu Xinqiang Gao Jun Shen Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou341119China Faculty of Materials metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou341000China School of Rare Earth and New Materials Engineering Gannan University of Science and TechnologyGanzhou341000China Department of Energy and Power Engineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing100081China

In perovskite EuTiO_(3),the magnetic characteristics and magnetocaloric effect(MCE) can be flexibly regulated by converting the magnetism from antiferromagnetic to *** the present work,a series of Eu(Ti,Nb,Mn)O_(3) compounds,abbreviated as ETNMO for convenience of description,was fabricated and their crystallography,magnetism together with cryogenic magnetocaloric effects were systematically *** crystallographic results demonstrate the cubic perovskite structure for all the compounds,with the space group of *** magnetic phase transitions are observed in these second-order phase transition(SOPT) *** joint substitution of elements Mn and Nb can considerably manipulate the magnetic phase transition process and magnetocaloric performance of the ETNMO *** the Mn content increases,gradually widened-ΔS_(M)-T curves are obtained,and two peaks with a broad shoulder are observed in the-ΔS_(M)-T curves for Δμ_(0)H≤0-1 *** a field change of 0-5 T,the values of maximum magnetic entropy change(-ΔS_(M)^(max)) and refrigeration capacity(RC) are evaluated to be 34.7 J/(kg·K) and 364.9 J/kg for EuTi_(0.8625)Nb_(0.0625)Mn_(0.075)O_(3), 27.8 J/(kg·K) and367.6 J/kg for EuTi_(0.8375)Nb_(0.0625)Mn_(0.1)O_(3),23.2 J/(kg·K) and 369.2 J/kg for EuTi_(0.8125)Nb_(0.0625)Mn_(0.125)O_(3),17.1 J/(kg·K) and 357.6 J/kg for EuTi_(0.7875)Nb_(0.0625)Mn_(0.15)O_(3),*** co nsiderable MCE parameters make the ETNMO compounds potential candidates for cryogenic magnetic refrigeration.

关键词： ETNMO perovskites Cryogenic refrigeration Magnetic phase transition Magnetocaloric effect Rare earths

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Correlation of work function and stacking fault energy through Kelvin probe force microscopy and nanohardness in diluteα-magnesium

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Journal of Magnesium and Alloys 2024年第1期12卷 237-250页

作者： Yigit Türe Ali Arslan Kaya Hüseyin Aydin Jiang Peng Servet Turan Eskisehir Technical University Porsuk Vocational SchoolElectronics and Automation DepartmentProgram of MechatronicsEskisehirTurkey Mugla Sitki Kocman University Engineering FacultyMetallurgy and Materials Engineering DepartmentMuglaTurkey Hüseying Aydın TUBITAK MRCTurkey Jiang Peng Chongqing UniversityChina Eskisehir Technical University Engineering FacultyMaterials Science and Engineering DepartmentEskisehirTurkey

Electronic interactions of the group 2A elements with magnesium have been studied through the dilute solid solutions in binary Mg-Ca,Mg-Sr and Mg-Ba *** investigation incorporated the difference in the‘Work Function'(ΔWF)measured via Kelvin Probe Force Microscopy(KPFM),as a property directly affected by interatomic bond types,*** electronic structure,nanoindentation measurements,and Stacking Fault Energy values reported in the *** was shown that the nano-hardness of the solid-solutionα-Mg phase changed in the order of Mg-Ca>Mg-Sr>***,it was shown,by also considering the nano-hardness levels,that SFE of a solid-solution is closely correlated with its‘Work Function'***-hardness measurements on the eutectics andΔWF difference between eutectic phases enabled an assessment of the relative bond strength and the pertinent electronic structures of the eutectics in the three *** withΔWF and at least qualitative verification of those computed SFE values with some experimental measurement techniques were considered important as those computational methods are based on zero Kelvin degree,relatively simple atomic models and a number of *** asserted by this investigation,if the results of measurement techniques can be qualitatively correlated with those of the computational methods,it can be possible to evaluate the electronic structures in alloys,starting from binary systems,going to ternary and then multi-elemental *** investigation has shown that such a qualitative correlation is *** all,the SFE values are not treated as absolute values but rather become essential in comparative investigations when assessing the influences of alloying elements at a fundamental level,that is,free electron density *** study indicated that the principles of‘electronic metallurgy'in developing multi-elemental alloy systems can be followed via practical experimental methods,i.e.ΔWF measurements using KPF

关键词： Mg alloys Dilute alloys Work function Stacking fault energy Kelvin probe force microscopy Short range order Miedema Nanoindentation Eutectics

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Exploring the potential of olivine-containing copper-nickel slag for carbon dioxide mineralization in cementitious materials

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International Journal of Minerals,metallurgy and Materials 2024年第3期31卷 562-573页

作者： Qianqian Wang Zequn Yao Lijie Guo Xiaodong Shen College of Materials Science and Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing 211816China BGRIMM Technology group Beijing 100160China

Water-quenched copper-nickel metallurgical slag enriched with olivine minerals exhibits promising potential for the production of CO_(2)-mineralized cementitious *** this work,copper-nickel slag-based cementitious material(CNCM)was synthesized by using different chemical activation methods to enhance its hydration reactivity and CO_(2) mineralization *** water curing ages and carbonation conditions were explored related to their carbonation and mechanical properties ***,thermogravimetry differential scanning calorimetry and X-ray diffraction methods were applied to evaluate the CO_(2) adsorption amount and carbonation products of *** development of carbonated CNCM blocks was examined by backscattered electron imaging(BSE)with energy-dispersive X-ray *** showed that among the studied samples,the CNCM sample that was subjected to water curing for 3 d exhibited the highest CO_(2) sequestration amount of 8.51wt%at 80℃and 72 h while presenting the compressive strength of 39.07 *** result indicated that 1 t of this CNCM can sequester 85.1 kg of CO_(2) and exhibit high compressive *** the addition of citric acid did not improve strength development,it was beneficial to increase the CO_(2) diffusion and adsorption amount under the same carbonation conditions from BSE *** work provides guidance for synthesizing CO_(2)-mineralized cementitious materials using large amounts of metallurgical slags containing olivine minerals.

关键词： copper-nickel slag fayalite CO_(2)sequestration cementitious material admixtures carbonation conditions

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Fe_(3)O_(4)对黄铜矿在酸性硫酸铁溶液中铜溶解氧化还原反应的影响

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Transactions of Nonferrous Metals Society of China 2024年第6期34卷 1965-1975页

作者： Kolela J NYEMBWE Elvis FOSSO-KANKEU Frans WAANDERS Martin MKANDAWIRE Didier K NYEMBWE Bhekie B MAMBA Water Pollution Monitoring and Remediation Initiatives Research group School of Chemical and Minerals EngineeringFaculty of EngineeringNorth-West UniversityPotchefstroomSouth Africa Department of Mining Engineering College of Science Engineering and TechnologyUniversity of South AfricaFlorida Science CampusJohannesburgSouth Africa Department of metallurgy Faculty of Engineering and Built EnvironmentUniversity of JohannesburgDoornfonteinJohannesburgSouth Africa Department of Chemistry School of Science and TechnologyCape Breton UniversityCanada School of Mining Metallurgy and Chemical EngineeringFaculty of Engineering and the Built EnvironmentUniversity of JohannesburgJohannesburgSouth Africa Institute for Nanotechnology and Water Sustainability College of Science Engineering and TechnologyUniversity of South AfricaFlorida Science CampusJohannesburgSouth Africa

由于钝化层的形成,黄铜矿(CuFeS_(2))在氧化条件下浸出通常具有溶解速率缓慢的特点。为了将黄铜矿浸出过程中的钝化效应降至最低并提高铜的回收率,研究了CuFeS_(2)在不同pH值(1.0、1.5和1.8)和温度(25和50℃)条件下浸出时,向Fe_(2)(SO_(... 详细信息

由于钝化层的形成,黄铜矿(CuFeS_(2))在氧化条件下浸出通常具有溶解速率缓慢的特点。为了将黄铜矿浸出过程中的钝化效应降至最低并提高铜的回收率,研究了CuFeS_(2)在不同pH值(1.0、1.5和1.8)和温度(25和50℃)条件下浸出时,向Fe_(2)(SO_(4))_(3)−H_(2)SO_(4)浸出剂中添加磁铁矿(Fe_(3)O_(4))对铜溶解速率的影响。结果表明,溶液pH值、电位和温度在溶解过程中起着关键作用。在pH 1.8、50℃和400 mV的条件下,Fe_(3)O_(4)−CuFeS_(2)混合体系中铜的回收率达到最大值(70%),而未添加Fe_(3)O_(4)时,CuFeS_(2)中铜的回收率较低(48%)。添加Fe_(3)O_(4)有助于维持较高的氧化还原值。添加Fe_(3)O_(4)还使活化能从79.04 kJ/mol降低到53.69 kJ/mol。这表明,当Fe_(3)O_(4)存在时,由于形成了更易溶解的中间体斑铜矿(Cu_(5)FeS_(4))和辉铜矿(Cu_(2)S),CuFeS_(2)更易被氧化。两种溶解过程都受到矿物表面的化学控制。此外,对浸出残渣的矿物学分析表明,当无Fe_(3)O_(4)存在时,作为表面钝化物的黄钾铁矾浓度较高。因此,添加Fe_(3)O_(4)减少了钝化层的形成,提升了铜的回收率。

关键词：黄铜矿溶解磁铁矿电偶钝化

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Synthesis of nanostructured Mg_2FeH_6 hydride and hydrogen sorption properties of complex

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Transactions of Nonferrous Metals Society of China 2010年第12期20卷 2281-2288页

作者：李松林汤盛龙刘燚彭书科崔建民 State Key Laboratory of Powder metallurgy Central South University Powder metallurgy Corporation Ltd. Laiwu Iron and Steel Group

Reactive mechanical alloying(RMA)was carried out in a planetary ball mill for the synthesis of ternary hydride Mg2FeH6 for hydrogen *** formation mechanism of Mg2FeH6 in RMA process and the sorption properties of the products were *** results show that Mg2FeH6 has a yield ratio around 80%,and a grain size below 10 nm in the powder synthesized by milling 3Mg+Fe mixture for 150 h under the hydrogen pressure of 1 *** synthesized powder possesses a high hydrogen capacity and good sorption kinetics,and absorbs 4.42%(mass fraction)of hydrogen within 200 s at 623 K under the hydrogen pressure of 4.0 *** releasing hydrogen at 653 K under 0.1 MPa,it desorbs 4.43%(mass fraction)of hydrogen within 2 000 *** addition of Ti increases the hydrogen desorption rate of the complex in the initial 120 s of the desorption process.

关键词： reactive mechanical alloying(RMA) metal hydride hydrogen storage material kinetics fuel cell

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晶格畸变增强卤化锑晶体团簇的自陷激子发射（英文）

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Science China Materials 2024年

作者：刘达何敬敬孙玉婷刘心翊彭玉李庆杨化桂牛强杨双侯宇 Key Laboratory for Ultrafine Materials of Ministry of Education Shanghai Engineering Research Center of Hierarchical Nanomaterials School of Materials Science and Engineering East China University of Science and Technology China National enterprise technology center Inner Mongolia Erdos Electric Power and Metallurgy Group Company Limited

零维钙钛矿材料以自陷激子引起的宽带发射为特征,是一种很有前途的刺激响应和光加密材料.然而,现有的研究主要集中在结构相变对光物理性质的影响上,对自陷激子的发射机制缺乏深入了解.本文证明了零维卤化锑单晶中的脱水反应,在不诱导结...

零维钙钛矿材料以自陷激子引起的宽带发射为特征,是一种很有前途的刺激响应和光加密材料.然而,现有的研究主要集中在结构相变对光物理性质的影响上,对自陷激子的发射机制缺乏深入了解.本文证明了零维卤化锑单晶中的脱水反应,在不诱导结构相变的基础上显著增强了自陷激子的发射,导致光致发光量子产率从3.5%大幅提高到91.4%.利用原位X射线衍射和光致发光技术揭示了晶体结构和光致发光强度之间的定性关系,证明了在脱水过程中引入了丰富的晶格畸变.温度依赖的荧光光谱和瞬态吸收光谱表明,晶格畸变导致中等的电子-声子耦合强度和更高的激子结合能,加速了自陷激子从非辐射复合单重态弛豫到辐射复合三重态,进而表现出增强的光致发光.作为概念验证,在防伪、可重写发光纸和湿度传感等多重场景中实现了应用.这一发现阐明了自陷激子的发射机制,并为设计可切换发光材料提供了一条新途径.

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Influence of silicon coating on the corrosion resistance of Zn-Al-Mg-RE-Si alloy

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Journal of Rare Earths 2010年第S1期28卷 378-381页

作者：刘奎仁马鹏程蒲年文陈建设韩庆 School of Material and metallurgy Northeastern University Sichuan Chuanwei group Ltd.

The electric arc spraying method was used to prepare the Zn-Al-Mg-RE-Si alloy coating with different content of *** corrosion resisting property was measured by copper accelerated salt spray(CASS) and corrosion weightless *** influence of silicon content on the corrosion resisting property was investigated by XRD,SEM,polarization curve and electrochemical impedance spectroscopy(EIS) and the electrochemical property of coating in the corrosion process was *** results showed that the density of coating was improved significantly since the major nonequilibrium glass-like state phase was composed of silicon and other metals existed in the Zn-Al-Mg-RE-Si alloy coating,which prevented the corrosive medium and retarded the corrosion velocity because of compact corrosion products in the corrosion *** Zn-Al-Mg-RE-Si coating had better corrosion resistance than the Zn-Al-Mg-RE because of more positive potential,half corrosion current density and double electrochemical reaction resistance.

关键词： corrosion electric arc spraying CASS weightless corrosion resisting property rare earths

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Factors Influencing the Direct Electrochemical Reduction of Nb_2O_5 Pellets to Nb Metal in Molten Chloride Salts

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Acta Metallurgica Sinica(English Letters) 2017年第3期30卷 218-227页

作者： D.Sri Maha Vishnu N.Sanil K.S.Mohandas K.Nagarajan Chemistry group Indira Gandhi Centre for Atomic Research Materials Chemistry group Department of Materials Science and MetallurgyUniversity of Cambridge

Powder compacted and sintered Nb205 pellets were cathodically polarised against graphite anode in calcium chloride melt at 1173 K to study the influence of various factors on the electrochemical reduction of the oxide. The parameters were; duration and temperature of electrolysis, open porosity of pellets, nature of anode, mode of electrolysis and configuration of the oxide cathode. The experiments were also conducted in KC1, KC1-25 tool% CaC12 and NaC1 melts to understand the effect of melt composition on the electroreduction. Different Ca-Nb-O and Nb-O intermediates were found in the pellets electrolysed for different durations of time in CaC12 melt which eventually reduced to Nb. The current efficiency of the process decreased with increasing duration of electrolysis. Decrease in electrolysis temperature from 1 173 to 1073 K led to the decrease in the rate of reduction of the oxide pellets. Pellets with high open porosity reduced faster. Carbon contamination of the melt was relatively less when pyrolytic graphite was used as anode. Of all the melts studied, the reduction was found to be better in calcium chloride melt, that too when alumina crucible was used as container of the melt.

关键词： Fray-Farthing-Chen (FFC) Cambridge process Electrochemical reduction Open porosity Niobium pentoxide Calcium chloride

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Modulation of zeolite surface realizes dynamic copper species redispersion

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Chinese Journal of Structural Chemistry 2024年第6期43卷 6-7页

作者： Guoliang Liu Zhiqiang Liu Anmin Zheng Interdisciplinary Institute of NMR and Molecular Sciences School of Chemistry and Chemical EngineeringThe State Key Laboratory of Refractories and MetallurgyWuhan University of Science and TechnologyWuhan430081PR China State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan430071PR China

Zeolite-based metal nanoparticles(NPs)catalysts have shown promising applications in fuel production,petro-and fine-chemical manufacture,biomass refinery,and so *** of hydroxyl groups on the zeolite surface has proven to be effective in boosting catalytic reactions over metal-zeolite *** example,modifying the wettability of ZSM-5 and titanium silicalite-1(TS-1)crystals by surface hydrophobization drastically enhances catalytic performance of zeolites encapsulated AuPd[1]and Pt[2]NPs in methane oxidation and aldehydes/ketones hydrogenation,*** fact,two kinds of hydroxyl groups are present in zeolite materials,which refers to bridged hydroxyls[Si-O(H)-Al]and silanols[Si-O(H)].Both hydroxyl groups are defects of zeolite framework structures,which provides anchor points in dispersing metals[3].The former hydroxyl group is tunable to control acidity by adjusting Si/Al ratio in zeolite,whereas the role of silanols is not fully understood[4],particularly in the dispersion of metal NPs.

关键词： zeolite dispersion aldehydes

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