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Direct microwave leaching conditions of rare earth elements in fluorescent wastes

Journal of Rare Earths 2024年第6期42卷 1165-1174,I0007页

作者： A.Bilen B.Birol M.N.Saridede S.S.Kaplan M.S.Sonmez Department of Metallurgical and Materials Engineering Yildiz Technical UniversityIstanbulTurkey Department of Chemical Engineering and Materials Science Stevens Institute of TechnologyNew JereyUSA Department of Metallurgical and Materials Engineering Istanbul Technical UniversityIstanbulTurkey

The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent lamp.and the yields were compared.In the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were investigated.The highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 min.Activation energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction controlled.Moreover,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed model.Concurrently,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.

关键词： Rare earth elements(REEs) Direct microwave leaching Fluorescent waste kinetic models Response surface method

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kinetic models of natural gas combustion in an internal combustion engine

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Journal of Natural Gas Chemistry 2010年第1期19卷 6-14页

作者： M. Mansha A. R Saleemi Badar M. Ghauri Department of Chemical Engineering University of Engineering & Technology Lahore 54570 Pakistan SUPARCO HQs Karachi 49430 Pakistan

In this study, combustion of methane was simulated using four kinetic models of methane in CHEMKIN 4.1.1 for 0-D closed internal combustion （IC） engine reactor. Two detailed （GRIMECH3.0 ＆ UBC MECH2.0） and two reduced （One step ＆ Four steps） models were examined for various IC engine designs. The detailed models （GRIMECH3.0, ＆ UBC MECH2.0） and 4-step models successfully predicted the combustion while global model was unable to predict any combustion reaction. This study illustrated that the detailed model showed good concordances in the prediction of chamber pressure, temperature and major combustion species profiles. The detailed models also exhibited the capabilities to predict the pollutants formation in an IC engine while the reduced schemes showed failure in the prediction of pollutants emissions. Although, there are discrepancies among the profiles of four considered model, the detailed models （GRIMECH3.0 ＆ UBC MECH2.0） produced the acceptable agreement in the species prediction and formation of pollutants.

关键词： kinetic models detailed models reduced models combustion methane IC engine

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Comparison of kinetic models for isothermal CO_2 gasification of coal char–biomass char blended char

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International Journal of Minerals,Metallurgy and Materials 2015年第4期22卷 363-370页

作者： Hai-bin Zuo Wei-wei Geng Jian-liang Zhang Guang-wei Wang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

This study investigated the isothermal gasification reactivity of biomass char （BC） and coal char （CC） blended at mass ratios of 1：3, 1：1, and 3：1 via isothermal thermogravimelric analysis （TGA） at 900, 950, and 1000℃ under CO2. With an increase in BC blending ra- tio, there were an increase in gasification rate and a shortening of gasification time. This could be attributed to the high specific surface area of BC and the high uniformity of carbon structures in CC when compared to those in BC. Three representative gas-solid kinetic models, namely, the volumetric model （VM）, grain model （GM）, and random pore model （RPM）, were applied to describe the reaction behavior of the char. Among them, the RPM model was considered the best model to describe the reactivity of the char gasification reaction. The activa- tion energy of BC and CC isothermal gasification as determined using the RPM model was found to be 126.7 kJ/mol and 210.2 kJ/mol, re- spectively. The activation energy was minimum （123.1 kJ/mol） for the BC blending ratio of 75%. Synergistic effect manifested at all mass ratios of the blended char, which increased with the gasification temperature.

关键词： ironmaking coal char biomass gasification kinetic models synergistic effect

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Modeling the Drying kinetics of Pigeon Pea [Cajanus cajan (L.) Millspaugh]

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Open Journal of Applied Sciences 2024年第6期14卷 1425-1436页

作者： Nadia Pamela Gladys Pambou-Tobi Arnaud Wenceslas Geoffroy Tamba Sompila Michel Elenga Reyes Herdenn Gampoula Gloire Horiane Louya Banzouzi Sylvia Petronille Ntsossani National Institute for Research in Engineering Sciences Innovation and Technology Brazzaville Congo National Polytechnic School Marien Ngouabi University Brazzaville Congo Pole of Excellence in Food and Nutrition Faculty of Science and Technology Marien Ngouabi University Brazzaville Congo

We set out to model the oven-drying kinetics of a legume known as pigeon pea, harvested in the Bouenza department in the south-west of the Republic of Congo. The drying kinetics of pigeon peas was carried out in an oven under experimental conditions using temperatures of: 50°C, 60°C and 70°C. Seven mathematical models were used to describe pigeon pea drying. During drying, water loss was faster and shorter at 70°C [10.446 g/25 g wet weight (wwb) for 320 min (5.3 h)] compared to 50°C [10.996 g/25 g wet weight (wwb) for 520 min (8.6 h)] and 60°C [10.616 g/25 g wet weight (wwb) for 420 min (7.0 h)] where it was slower and longer. With regard to modeling, and based on the principle of choosing the right model focusing on the high value of R2 and low values of χ2 and RMSE, two models were selected, the Midili model for temperatures of 50°C and 60°C and the Henderson and Pabis model modified for temperature of 70°C showed better results. The R2, χ2 and RMSE values calculated for pigeon pea are 0.99985, 3.93404E-5 and 0.00627;0.9997, 9.245E-5 and 0.00962;0.99996, 1.56332E-5 and 0.00395 respectively at 50°C, 60°C and 70°C.

关键词： Cajanus cajan Legume kinetic models Drying

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kinetics of the hydrogen absorption and desorption processes of hydrogen storage alloys: A review

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International Journal of Minerals,Metallurgy and Materials 2022年第1期29卷 32-48页

作者： Qian Li Xi Lin Qun Luo Yuʼan Chen Jingfeng Wang Bin Jiang Fusheng Pan National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

High hydrogen absorption and desorption rates are two significant index parameters for the applications of hydrogen storage tanks.The analysis of the hydrogen absorption and desorption behavior using the isothermal kinetic models is an efficient way to investigate the kinetic mechanism.Multitudinous kinetic models have been developed to describe the kinetic process.However,these kinetic models were de-duced based on some assumptions and only appropriate for specific kinetic measurement methods and rate-controlling steps(RCSs),which sometimes lead to confusion during application.The kinetic analysis procedures using these kinetic models,as well as the key kinetic parameters,are unclear for many researchers who are unfamiliar with this field.These problems will prevent the kinetic models and their analysis methods from revealing the kinetic mechanism of hydrogen storage alloys.Thus,this review mainly focuses on the summarization of kinetic models based on different kinetic measurement methods and RCSs for the chemisorption,surface penetration,diffusion of hydrogen,nucleation and growth,and chemical reaction processes.The analysis procedures of kinetic experimental data are expounded,as well as the effects of temperature,hydrogen pressure,and particle radius.The applications of the kinetic models for different hydrogen storage alloys are also introduced.

关键词： hydrogen storage metal hydrides hydrogen absorption process hydrogen desorption process kinetic models

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Development of Magnetite/Graphene Oxide Hydrogels from Agricultural Wastes for Water Treatment

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Journal of Renewable Materials 2022年第7期10卷 1889-1909页

作者： Hebat-Allah STohamy Mohamed El-Sakhawy Samir Kamel Cellulose and Paper Department National Research CentreCairo12622Egypt

A novel magnetic hydrogel loaded with graphene oxide(GO)was developed in this study.Firstly,GO was prepared from bagasse through a single step via oxidation in the presence of ferrocene under muffled atmospheric conditions,followed by the loading of different amounts of magnetite onto GO via co-precipitation reaction of iron onto GO sheets.Finally,the 2-acrylamido-2-methyl-1-propane sulfonic acid was grafted onto carboxymethyl cellulose in the presence of magnetite GO and N,N′-methylenebisacrylamide as crosslinker yielded hydrogel.The structure,morphological,and thermal behavior of the prepared hydrogels were investigated.In addition,the adsorption performance of Ni(Ⅱ)ions from aqueous media by the prepared hydrogels was investigated as a function of temperature,time,and concentration of adsorbate in a batch system.The results demonstrated a remarkable enhancement in the adsorption process of Ni(Ⅱ)(Removal efficiency=98.82%).All isotherms were found to fit the Langmuir model best.The adsorption properties of both magnetic GO and magnetic hydrogel showed promising properties as green and cheap adsorbents.

关键词： Magnetite graphene oxide hydrogel Ni(Ⅱ)adsorption kinetic models thermodynamics

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Effects of Nb Alloying on Nano-Crystallization kinetics of Fe_(55-x)Cr_(18)Mo_7B_(16)C_4Nb_x(x=0, 3) Bulk Amorphous Alloys

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Journal of Materials Science & Technology 2011年第8期27卷 735-740页

作者： S. Ahmadi H.R. Shahverdi S.S. Saremi Faculty of Engineering Department of Materials Science Tarbiat Modares University

Crystallization kinetics of Fe55-xCrzsMo7B10C4Nbx（x= 0, 3） bulk amorphous alloys were analyzed using X-ray diffraction and differential scanning; calorimetric （DSC） tests. In practice, crystallization and growth mechanism were evaluated using DSC tests at four different heating rates （10, 20, 30, and 40 K/rain） and kinetic models. Two-step crystallization behavior was observed when Fe55Cr18MOTB16C4 and Fe52Cr18MoTB16C4Nb3 bulk amorphous alloys were annealed, where Fe36Cr12M010 phase was crystallized in the first step of crystallization. Results show that Fe36Cr12Mo10 and Fe3C phases were crystallized in the structures of the alloys after further annealing： process. Activation energy for the crystallization of Fe36Cr12Mozo phase was measured to be 543 kJ/mol in Fe52Cr18MoTB16C4Nb3 alloy and 375 kJ/mol for Fe55Cr18Mo7B16C4 alloy according to Kissinger-Starink model. Moreover, a two-dimensiona nucleation rate was found in Fe52Cr18Mo7B16C4Nb3 diffusion controlled growth mechanism with decreasing alloy whereas a three-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in crystallization of Fe36Crz2Mo10 phase during annealing of Fe55Cr18MoTB16C4 alloy. TEM （transmission electron microscopy） observations reveal that crystalline Fe36Cr12M010 phase nucleated in the structures of the alloys in an average size of 10 nm with completely mottled morphology.

关键词： Avrami exponent Crystallization kinetic models Growth mechanisms Bulk amorphous alloys

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A review of the thermal stability of metastable austenite in steels:Martensite formation

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Journal of Materials Science & Technology 2021年第32期91卷 200-214页

作者： Yong Li David San Martín Jinliang Wang Chenchong Wang Wei Xu State key laboratory of rolling and automation Northeastern UniversityShenyang 110819China Materalia Research Group Centro Nacional de Investigaciones Metalúrgicas(CENIM-CSIC)Avda Gregorio del Amo 8Madrid E-28040Spain School of Mechanical and Power Engineering Guangdong Ocean UniversityZhanjiang 524088China

Metastable austenite plays a critical role in achieving improved combinations of high strength and high ductility/toughness in the design of advanced high-strength steels(AHSS). The thermal stability of metastable austenite determines the transformation characteristics of AHSS and thus primarily determines the microstructure evolution during complex processes, e.g., the quenching and partitioning process, to achieve the desirable microstructure. This study provides a review of the thermal stability of austenite and its influence on martensitic transformation from both experimental and theoretical modeling perspectives. From the experimental perspective, factors affecting the thermal stability are analyzed,the relative sensitivities are compared, and their corresponding mechanisms are discussed. From the theoretical modeling perspective, the most representative kinetic models that describe athermal and isothermal martensitic transformation are reviewed. The advantages, shortcomings, and applicability of each model are discussed. The systematic review of both experimental and theoretical aspects reveals critical factors in tailoring the stability of metastable austenite and, therefore, provides guidance for the design of advanced steels.

关键词： Austenite Thermal stability Martensitic transformation kinetic models

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Thermodynamics and kinetics of hydriding and dehydriding reactions in Mg-based hydrogen storage materials

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Journal of Magnesium and Alloys 2021年第6期9卷 1922-1941页

作者： Qian Li Yangfan Lu Qun Luo Xiaohua Yang Yan Yang Jun Tan Zhihua Dong Jie Dang Jianbo Li Yuan Chen Bin Jiang Shuhui Sun Fusheng Pan National Engineering Research Center for Magnesium Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400044China State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing 400044China State Key Laboratory of Advanced Special Steels Shanghai Key Laboratory of Advanced FerrometallurgySchool of Materials Science and EngineeringShanghai UniversityShanghai 200444China Institute of Quantum and Sustainable Technology(IQST) School of Chemistry and Chemical EngineeringJiangsu UniversityZhenjiang212013China Institut National de la Recherche Scientifique-énergie Matériaux et Télécommunications J3×1S2QuébecCanada

Mg-based materials are one of the most promising hydrogen storage candidates due to their high hydrogen storage capacity,environmental benignity,and high Clarke number characteristics.However,the limited thermodynamics and kinetic properties pose major challenges for their engineering applications.Herein,we review the recent progress in improving their thermodynamics and kinetics,with an emphasis on the models and the influence of various parameters in the calculated models.Subsequently,the impact of alloying,composite,and nanocrystallization on both thermodynamics and dynamics are discussed in detail.In particular,the correlation between various modification strategies and the hydrogen capacity,dehydrogenation enthalpy and temperature,hydriding/dehydriding rates are summarized.In addition,the mechanism of hydrogen storage processes of Mg-based materials is discussed from the aspect of classical kinetic theories and microscope hydrogen transferring behavior.This review concludes with an outlook on the remaining challenge issues and prospects.

关键词： Magnesium-based hydrogen storage materials Hydriding/dehydriding reactions Thermodynamics kinetic models Analysis methods

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Advances in reactive co-precipitation technology for preparing high-performance cathodes

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Green Carbon 2023年第2期1卷 193-209页

作者： Zhenzhen Wang Li Yang Chunliu Xu Jingcai Cheng Junmei Zhao Qingshan Huang Chao Yang Key Laboratory of Biofuels Qingdao Institute of Bioenergy and Bioprocess Technology(QIBEBT)Chinese Academy of Sciences(CAS)QingdaoShandong 266101China CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Shandong Energy Institute Qingdao 266101ShandongChina Qingdao New Energy Shandong Laboratory Qingdao 266101ShandongChina

Reactive crystallization plays an essential role in the synthesis of high-quality precursors with a narrow particle size distribution,dense packing,and high sphericity.These features are beneficial in the fabrication of high-specific-capacity and long-cycle-life cathodes for lithium-ion and sodium-ion batteries.However,in industrial production,designing and scaling-up crystallizers involves the use of semi-empirical approaches,making it challenging to satisfactorily meet techno-economic requirements.Furthermore,there is still a lack of in-depth knowledge on the theoretical models and technical calculations of the current co-precipitation process.This review elaborates on critical advances in the theoretical guidelines and process regulation strategies using a reactive crystallizer for the preparation of precursors by co-precipitation.The research progress on the kinetic models of co-precipitation reactive crystallization is presented.In addition,the regulation strategies for the reactive crystallization process of lithium-ion ternary cathodes are described in detail.These include the influence of different reactive crystallizer structures on the precursor's morphology and performance,the intelligent online measurement of efficient reactive crystallizers to ensure favorable conditions of co-precipitation,and preparing the precursor with a high tap density by increasing its solid holdup.A controllable reactive crystallization process is described in terms of the structural design with concentration gradient materials and bulk gradient doping of advantageous elements(such as magnesium ion)in lithium-ion cathodes and the fabrication of sodium-ion cathodes with three typical materials-Prussian blue analogues,transition metal oxides,and polyanionic phosphate compounds being involved.

关键词： Reactive crystallization kinetic models Crystallizer Regulation strategy Cathode materials

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