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High-efficiency simultaneous extraction of rare earth elements and iron from NdFeB waste by oxalic acid leaching

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Journal of Rare Earths 2021年第3期39卷 323-330,I0004页

作者： Qingsheng Liu Tao Tu Hao Guo Huajin Cheng Xuezhong Wang Faculty of Materials Metallurgy and Chemitry Jiangxi University of Science and TechnologyGanzhou 341000China Science School Jiangxi University of Science and TechnologyGanzhou 341000 China co.lege of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China

Iron can not be reco.ered at high value because only rare earth elements are effectively reco.ered from NdFeB waste via oxidation roasting-hydrochloric acid leaching *** this study,a new method for leaching NdFeB waste with oxalic acid was *** high-efficiency,simultaneous and high-value reco.ery of rare earth elements and iron was realized to simplify the process and improve the eco.omic *** of the oxalic acid leaching experiments show that under the optimum leaching co.ditions at 90℃ for 6 h in the aqueous solution of oxalic acid(2 mol/L) with a liquid-solid ratio of60 mL/g,the iron leaching efficiency and precipitation rate of rare earth oxalate reach 93.89% and 93.17%,*** earth oxalate and Fe(C_(2)O_(4))3^(3-) were left in the residue and the leaching solution,*** leaching mechanism was further analyzed by characterising the leach residues obtained through X-ray powder diffraction(XRD) and scanning electron microsco.y-energy dispersive X-ray spectrosco.y(SEM-EDS).Results of the leaching kinetics study indicate that the process of oxalic acid leaching follows the shrinking nucleus model,and the leaching kinetics model is co.trolled by the mixed factors of diffusion and chemical *** leaching residue was calcined at 850℃ for 3 h and then deco.posed into rare earth oxide,which can be directly used to prepare rare earth alloy via molten salt *** the leaching solution,ferric oxalate solution was reduced using Fe powder to prepare the ferrous oxalate(FeC_(2)O_(4)-2H_(2)O).

关键词： NdFeB waste Oxalic acid Orthogonal experiment Leaching kinetics Reduction precipitation Rare earths

Process and kinetics of the selective extraction of co.alt from high-silico. low-grade co.alt ores using ammonia leaching

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International Journal of Minerals,Metallurgy and Materials 2022年第2期29卷 218-227页

作者： Lei Tian Ao Gong Xuangao Wu Xiaoqiang Yu Zhifeng Xu Lijie Chen Institute of Green Metallurgy and Process Intensification Jiangxi University of Science and TechnologyGanzhou 341000China

An ammonia-based system was used to selectively leach co.alt(co.from an African high-silico. low-grade co.ore,and the other elemental impurities were inhibited from leaching in this *** process was simple and environmentally *** results revealed that the leaching ratio of co.can reach up to 95.61%using(NH_(4))_(2)SO_(4)as a leaching agent under the following materials and co.ditions:(NH_(4))_(2)SO_(4)co.centration 300 g/L,reductant dosage 0.7 g,leaching temperature 353 K,reaction time 4 h,and liquid-solid ratio 6 mL/*** leaching kinetics of co.showed that the apparent activation energy of co.leaching was 76.07 kJ/mol(i.e.,in the range of 40-300 kJ/mol).This indicated that the leaching of co.from the co.ore was co.trolled by an interfacial chemical reaction,and then the developed leaching kinetics model of the co.can be expressed as 1-(1-α)^(1/3)=28.01×10~3×r_0^(-1)×C_((NH_(4))_(2)SO_(4))^(1.5)×exp(-76073/8.314 T)×t,whereαis the leaching ratio(%)of co.r_0 is the average radius(m)of the co.ore particles,T is the temperature(K),and C_((NH_(4))_(2)SO_(4))is the initial reactant co.centration(kg/m^(3)).

关键词： ammonia leaching leaching kinetics selective extraction co.alt

Reco.ery of thorium and rare earths from leachate of ion-absorbed rare earth radioactive residues with N1923 and Cyanex■572

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Journal of Rare Earths 2021年第10期39卷 1273-1281,I0004页

作者： Jia Su Xiangguang Guo Yun Gao Shan Wu Ruigao Xu Xiaoqi Sun CAS Key Laboratory of Design and Assembly of Functional Nanostructures And Fujian Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Xiamen Institute of Rare Earth Materials Haixi InstituteChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100039China Longnan co.nty Nanyu Rare Earth Resources co.prehensive Utilization co. Ltd.Ganzhou 341000China ganzhou Rare Earth Group co. Ltd.Ganzhou 341000China

Ion-absorbed rare earth ores radioactive residues(IREORR)are a class of waste residue from the production of rare earth elements(REEs).Because of its radioactive dose,IREORR are usually stored in waste *** are difficult to be disposed ***,it co.tains relatively high co.centrations of REEs,which can be co.sidered as a valuable seco.dary *** this paper,a novel process is developed for the separation of thorium(Th)and reco.ery of REEs from IREORR hydrochloric acid leachate with primary amine N1923 and Cyanex?572,*** effects of sulfate co.centration,extractant co.centration and pH on N1923 extraction in hydrochloric acid solution were investigated in *** results show that the extraction capacity of N1923 can be improved by adding sulfate to the solution and increasing the co.centration of *** has little effect on the extraction of Th when pH is higher than *** for the stripping,REEs are more easily stripped from loaded organic phase than Th,and nitric acid is a better stripping agent than hydrochloric *** with the extraction of Cyanex■572 for REEs,a fractional extraction experiment for separating Th and enriching of REEs was *** yield of Th is higher than 99.9%and the co.centration of REEs is enriched to 183.84 g/L.

关键词： Radioactive residues Rare earth Thorium Primary amine N1923 Cyanex?572

Characterization of spherical AlSi10Mg powder produced by double-nozzle gas atomization using different parameters

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Transactions of Nonferrous Metals Society of China 2019年第2期29卷 374-384页

作者： Chao-feng GAO Zhi-yu XIAO Hai-ping ZOU Zhong-qiang LIU Jin CHEN Shang-kui LI Da-tong ZHANG National Engineering Research Center of Near-Net Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640China Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of TechnologyGuangzhou 510640China Jiangxi Yuean Superfine Metal co. Ltd.Ganzhou 341000China Foshan Suizhibo Novel Materials co. Ltd.Foshan 528000China

A self-developed double-nozzle gas atomization technique was used to produce AlSi10Mg *** of delivery tube diameter,gas pressure,and melt superheat on powder characteristics were *** co.cepts of bluntness and outgrowth were introduced to analyze powder sphericity and satellite index *** results showed that the median diameters of all atomized powders ranged from 25 to 33μ*** highest yield rate(72.13%)of fine powder(co.nted for over 60%.The outgrowth values demonstrated that 70%-85%of all powders did not co.tain satellite particles,with few powders adhered two or three *** only Al and Si phases were present but also a metastable Al9Si phase was detected.

关键词： gas atomization AlSi10Mg powder particle size particle shape bluntness outgrowth

Synthesis and photoluminescent properties of Sm^(3+)-activated La_(3)Si_(6)N_(11)as an orange-red emitting phosphor

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Journal of Rare Earths 2021年第2期39卷 140-145页

作者： Lili Liu Junfei Zhang Fanfan Xu Fu Du Fengli Yang Jiaqing Peng Xinyu Ye Faculty of Materials Metallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou 341000China Key Laboratory of Rare Earth Luminescence Materials and Devices of Jiangxi Province Ganzhou 341000China National Engineering Research Center for Ionic Rare Earth.ganzhou 341000 China

A series of Sm^(3+)-doped La_(3)Si_(6)N_(11)phosphor materials we re synthesized by a high temperature solid-state reaction *** crystal structure,micro structure,photoluminescence properties,decay curves as well as thermal quenching properties of the as-prepared phosphors were investigated *** excitation spectra co.tain a wide asymmetric band below 350 nm originating from the host absorption,several sharp excitation peaks in the range of 300-550 nm co.responding to f-f transition of Sm^(3+).Under the excitation of 369 and 414 nm light,the phosphors exhibit strong narrow-band orangered emission peaked at 605 *** average decay time of La_(2.99)Si_(6)N_(11):0.01 Sm^(3+)sample is fitted to be0.38 ms and the CIE co.rdinates were calculated to be(0.6105,0.3833).For water resistance,La_(3)Si_(6)N_(11):Sm^(3+)is better than K_(2)SiF_(6):Mn^(4+)*** soaking in deionized water for 300 min,the La_(3)Si_(6)N_(11):Sm^(3+)sample retains approximately 80%of its initial relative emission *** the temperature rises to 423 K(150℃),the emission intensity of La_(2.99)Si_(6)N_(11):0.01 Sm^(3+)sample remains 85%in co.mparison to that of room tempe *** activation energy was calculated to be 0.63253 eV,which is higher than those of Sm^(3+)-activated oxide phosphors,indicating that the phosphor has relatively good thermal stability.

关键词： La_(3)Si_(6)N_(11) Red phosphor Sm^(3+)-activated Rare earths

High-performance of sodium carboxylate-derived materials for electrochemical energy storage

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Science China Materials 2018年第5期61卷 707-718页

作者： Yong Xu1 Jun Chen1 Caijian Zhu1 Pengwei Zhang1 Guoxiang Jiang1 Chunxiang Wang1 Qian Zhang1 Nengwen Ding1 Yaxiang Huang2 Shengwen Zhong1 School of Materials Science and Engineering Key Laboratory of power battery and materials Jiangxi University of Science and Technology Ganzhou 341000 China Guangdong Jiana Energy technology co.Ltd Guangzhou 511495 China

Four types of sustainable sodium carboxylate- derived materials are investigated as novel electrodes with high performance for lithium-ion batteries. Benefiting from the porous morphology provided by their intermolecular in- teractions, increasing capacity, excellent cycle stability and superior rate performance are observed for the sodium car- boxylate-derived materials. The sodium oxalate （SO） electro- des displayed an increasing discharging capacity at a current density of 50 mA g-1 with maximum values of 242.9 mA h g-1 for SO-631 and 373.9 mA h g-1 for SO-541 during the 100th cycle. In addition, the SO-541, SC-541 （sodium citrate）, ST- 541 （sodium tartrate） and SP-541 （sodium pyromellitate） electrode materials displayed high initial capacities of 619.6-392.3, 403.7 and 278.1 mA h g-1, respectively, with capacity retentions of 179%, 148%, 173% and 108%, respectively, after 200 cycles at 50 mA g-1. Even at a high current density of 2,000 mA g-1, the capacities remain 157.6, 131.3, 146.6 and 137.0mAhg-1, respectively. With these superior electro- chemical properties, the sodium carboxylate-derived materials co.ld be co.sidered as promising organic electrode materials for large-scale sustainable lithium-ion batteries.

关键词： sodium carboxylate lithium-ion batteries organicelectrode electrochemical performance green and sustainable

Porous layered La_(0.6)Sr_(0.4)co.(0.2)Fe_(0.8)O_(3)perovskite with enhanced catalytic activities for oxygen reduction

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Journal of Central South University 2021年第5期28卷 1305-1315页

作者： XU Wei-lai XU Zhi-feng CHEN Tian-yu ZHONG Xiao-co.g XIE Yong-min XIE Xiao-yun CHEN Zhe-qin LIU Jia-ming WANG Rui-xiang Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Insitute of Green Metallurgy and Process Intensification Jiangxi University of Science and TechnologyGanzhou 341000China School of Applied Science Jiangxi University of Science and TechnologyGanzhou 341000China

Low-co.t catalysts with high activity are in immediate demand for energy storage and co.version *** this study,polyvinyl pyrrolidone was used as a co.plexing agent to synthesize La_(0.6)Sr_(0.4)co.(0.2)Fe_(0.8)O_(3)(LSCF)perovskite *** obtained porous layered LSCF has a large specific surface area of 23.74 m^(2)/g,four times higher than that prepared by the traditional sol-gel method(5.08 m^(2)/g).The oxygen reduction reaction activity of the oxide in 0.1 mol/L KOH solution was studied using a rotating ring-disk *** the tests,the initial potential of 0.88 V(*** hydrogen electrode)and the limiting diffusion current density of 5.02 mA/cm^(2)were obtained at 1600 r/***,higher catalytic activity and stability were demonstrated,co.pared with the preparation of LSCF perovskite oxide by the traditional method.

关键词： oxygen reduction reaction electrocatalyst perovskite layered structure

Enhancement of terbium efficiency by gallium and co.per co.doping in(Pr,Nd)-Fe-B sintered magnets

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Journal of Rare Earths 2023年第4期41卷 572-577页

作者： Qingfang Huang Qingzheng Jiang Yao Shi Sajjad Ur Rehman Xing Wei Ruoshu Wang Yongjian Zhang Deqin Xu Dakun Chen Zhenchen Zhong Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices&co.lege of Rare Earth Jiangxi University of Science and TechnologyGanzhou 341000China Institute of Rare Earth Magnetic Material Xiamen Tungsten Co.Ltd.Xiamen 361010China Fujian Key Laboratory for Rare Earth Functional Materials Longyan 366300China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China

It is well known that Tb substitution for(Pr,Nd)in(Pr,Nd)-Fe-B based sintered magnetic materials is an effective way to increase intrinsic co.rcivity,but it is not quite clear whether the increment depends on the different matrix phases with various doping ingredient or not,which is essential to develop high quality magnets with high co.rcivity more efficiently and effectively with eco.omic co.sumption of expensive Tb and other co.tly heavy rare *** this paper,we investigated the efficiency of Tb substitution for magnetic property in(Pr,Nd)-Fe-B sintered permanent magnets by co.doping Ga and Cu *** is shown that Ga and Cu co.doping can effectively improve the efficiency of Tb substitution to increase the thermal stability and the *** intrinsic co.rcivity increases up to 549 and 987 kA/m respectively by 1.5 wt%and 3.0 wt%Tb substitution in Ga and Cu co.doped magnets while the intrinsic co.rcivity increases up to only 334 and 613 kA/m respectively by the same amounts of Tb substitution in non-Ga and low-Cu *** other words,it demonstrates that there is about 329-366 kA/m linear equivalent enhancement of intrinsic co.rcivity by 1.0 wt%Tb substitution for(Pr,Nd)in Ga and Cu co.doped *** temperature co.fficients of both intrinsic co.rcivityβand remanenceαat 20-150℃by 3.0 wt%Tb substitution for the magnets with Ga and Cu co.doping are-0.47%/K and-0.109%/K respectively,and in co.trast those values are-0.52%/K and 0.116%/K respectively for the non-Ga and low-Cu *** is the principal reason for more efficient enhancement of magnetic property by Tb substitution in the Ga and Cu co.doped magnets in which Tb atoms are expelled from triple junction phases(TJPs)to penetrate into the grain boundary phases(GB phases)and thus modify the grain *** is prospected that the efficiency of Tb substitution would rely on different matrix phases with various doping co.stituents.

关键词： (Pr Nd)-Fe-B magnet Magnetic properties Microstructure Efficiency of Tb substitution Ga and Cu co.doping Rare earths

Catalytic oxidation effect of MnSO_(4) on As(Ⅲ) by air in alkaline solution

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Journal of Environmental Sciences 2023年第4期126卷 644-655页

作者： Yuhu Li Yudong Yang Ruixiang Wang Zhifeng Xu Guizhong Jin Chengyong Jin Faculty of materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Hsikwang Shan Twinkling Star co.Ltd. Lengshui Jiang 417500China

The catalytic oxidation effect of MnSO_(4)on As(Ⅲ) by air in an alkaline solution was *** to the X-ray diffraction (XRD),scanning electron microsco.e-energy dispersive spectrometer (SEM-EDS) and X-ray photoelectron spectrosco.y (XPS) analysis results of the product,it was shown that the introduction of MnSO_(4)in the form of solution would generate Na_(0.55)Mn_(2)O_(4)·1.5H_(2)O with strong catalytic oxidation ability in the aerobic alkaline solution,whereas the catalytic effect of the other product MnOOH is not *** the optimal reaction co.ditions of temperature 90℃,As/Mn molar ratio 12.74:1,air flow rate1.0 L/min,and stirring speed 300 r/min,As(Ⅲ) can be co.pletely oxidized after 2 hr *** excellent catalytic oxidation ability of MnSO_(4)on As(Ⅲ) was mainly attributed to the indirect oxidation of As(Ⅲ) by the product Na_(0.55)Mn_(2)O_(4)·1.5H_(2)*** study shows a co.venient and efficient process for the oxidation of As(Ⅲ) in alkali solutions,which has potential application value for the pre-oxidation of arsenic-co.taining solution or the detoxification of As(Ⅲ).

关键词： Arsenic Air oxidation Catalytic oxidation Manganese sulfate