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Decomposition of monazite in bayan obo rare earth ore by roasting of Na2CO3 pellets

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Journal of Rare Earths 2024年第10期42卷 1969-1978页

作者： Ruifeng Ma Jianfei Li Xiaowei Zhang Peijie Jia Zhaogang Liu Jinxiu Wu Fushan Feng Wenbin Xin College of Materials and Metallurgy Inner Mongolia University of Science and Technology key laboratory of Green Extraction and Efficient utilization of Light Rare Earth resources Ministry of Education key laboratory of Rare Earth Wet Metallurgy and Light Rare Earth Applications of inner mongolia Autonomous Region

To resolve the issue of rotary kiln agglomeration during the sodium carbonate roasting of dolomite rare earth ore,this study introduces an oxidation-sodization pellet roasting method for decomposing mixed rare earth *** focus of this paper lies in understanding the bonding and roasting mechanism of sodium polyacrylate as a binder to dolomite ore and examining the process index of Na2CO3pellets roasting-acid leaching using X-ray diffraction（XRD）,scanning ele ctron microscopy with energy dispersive spectroscopy（SEM-EDS）,and zeta potential analysis,The results indicate that sodium polyacrylate facilitates the bonding of sodium carbonate to monazite via adsorption of positive and negative charges,and upon roasting at 750℃ for 1.5 h to obtain rare earth *** conditions of a hydrochloric acid（HCl） concentration of 9 mol/L,a reaction for 60 min,a solid-to-liquid ratio（g:mL） of 1:5,and reaction temperature of 90℃,the leaching rates of rare earth elements and thorium（Th） reached maxima of 85.14% and 95.53%,*** process results in a yield of 47.61% for fluorine（F） and89.25% for phosphorus（P）.This research forms a foundation for the sodium carbonate roasting decomposition of mixed rare earth concentrates.

关键词： bayan obo Decomposition Extraction Pellets Rare earths

An electron spin resonance study of Eu doping effect in La_(4/3)Sr_(5/3)Mn_2O_7 single crystal

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Chinese Physics B 2014年第7期23卷 717-719页

作者：何利民冀钰吴鸿业徐宝孙运斌张雪峰鲁毅赵建军 Department of Physics Baotou Normal University inner mongolia key laboratory for utilization of bayan obo multi-metallic resources and Elected State Key LaboratoryInner Mongolia University of Science and Technology

The effect of Eu3＋ ion doping in the La sites of single-crystal La4/3Srs/3Mn2O7 was investigated. Electron spin resonance （ESR） was applied to La4/3Sr5/3Mn2O7 and （Lao.8Euo.2）4/3Sr5/3Mn2O7 single crystals. A phase separation and phase transitions were observed from the ESR spectra data. Between 350 K and 300 K, both paramagnetic resonance （PMR） and anisotropic ferromagnetic resonance （FMR） lines were observed in the ab plane and the c axis direction, suggesting a coexistence of the paramagnetic （PM） phase and the ferromagnetic （FM） phase. The magnetization measurement reveals a spin-glass-like behavior in single-crystal （Lao.8Euo.2）4/3 Sr5/3Mn2O7 below the temperature of spin freezing Tf （- 29.5 K）.

关键词： electron spin resonance manganite single crystal phase separation anisotropy

Kinetic Mechanism in the Process of Carbothermal Reduction of Ferrum Niobate

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Journal of Wuhan University of Technology(Materials Science) 2015年第5期30卷 918-922页

作者：李解李保卫 YANG Yong HAN Jicheng ZHAO Wenyu ZHANG Bangwen key laboratory of Comprehensive utilization of bayan obo multi-Metal resources Inner Mongolia University of Science and Technology

Ferrum niobate was synthesized by solid-phase sintering method in a vacuum carbon tube furnace at 1 300 ℃ for 180 min. The phase transformation of ferrum niobate carbothermal reduction process was studied by XRD. The reduction reactions of ferrum niobate in different temperature stages were determined by the TG-DSC curve. Meanwhile, according to the TG curve, the reaction kinetics parameters were calculated by *** integration and the control steps in different temperature stages were ascertained. The results showed that the reduction of ferrum niobate starts at the temperature of 1 000 ℃, and the reduction process carries out in two steps according to sintering *** a temperature range of 1 000-1 238 ℃(the first step), the main reduction products are Nb O2 and Fe; the kinetic equation of initial stage is [-ln(1-α)]4=kt, controlled by nucleation growth, and the apparent activation energy is 388 k J/mol; with the temperature increasing, the kinetic equation is α+(1-α)ln(1-α)=kt, which is the Valensi two-dimensional diffusion kinetic equation, and the apparent activation energy is 264.4 k J/mol. The main reaction in a range of 1 238-1 344 ℃(the second step) is the reduction of Nb O2 to Nb C, the kinetic equation is [(1-α)-1/3-1]2=kt, which is controlled by the three-dimensional diffusion, and the apparent activation energy is 482.7 k J/mol.

关键词： ferrum niobate carbothermal reduction kinetics

Thermodynamic Behaviors of Nb and P in Dephosphorization of Niobium-bearing Hot Metal with BaO-based Slag

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Journal of Iron and Steel Research International 2014年第S1期21卷 39-43页

作者： Yong-li JIN Zeng-wu ZHAO Jie-yu ZHANG Wen-jie NI inner mongolia key laboratory for utilization of bayan obo multi-metallic resources: Elected State key laboratory Inner Mongolia University of Science and Technology School of Materials Science and Engineering Shanghai University

The bayan obo iron ore contains valuable metallic elements such as niobium and rare earth elements. However, developing appropriate metallurgical processes to achieve effective dephosphorization of Nb-bearing hot metal meanwhile retaining Nb in the steel products remains a challenge. We carried out a thermodynamic study on dephosphorization of Nbbearing hot metal and investigated the effects of the initial [C] content and the dephosphorization temperature on oxidation behaviors of [Nb] and [P]. In particular, we focused on thermodynamic analysis of dephosphorization of Nb-bearing hot metal with highly basic BaO-based slag. The results showed that the highly basic BaO-based slag system is more suitable for dephosphorization under oxidative conditions, and increasing the [C] content favors dephosphorization of Nb-bearing hot metal without oxidizing [Nb]. Moreover, the values of equilibrium oxygen activity for oxidation reactions of [Nb] and [P] are increased as the dephosphorization temperature increases. Considering the hot metal containing 0.02% of [Nb] in Baotou Steel, thermodynamic calculations indicated that the content of [P] can be reduced to 0.02%–0.05% and [Nb] remains unoxidized when dephosphorization occurs at the cconditions of T=1573–1673 K, [C]=4.0%, [Nb]=0.02%, aP2O5=10-24, aNb2O5=10-10.

关键词： Niobium-bearing hot metal Niobium Dephosphorization Thermodynamics BaO-based slag

Hydrogen storage properties of mechanically milled La_2Mg_(17-x)wt.%Ni(x=0,50,100,150 and 200) composites

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Journal of Rare Earths 2013年第7期31卷 694-700页

作者：李霞赵栋梁张羊换许剑轶张国芳张胤 Department of Functional Material Research Central Iron and Steel Research Institute inner mongolia key laboratory for utilization of bayan obo multi-metallic resources:Elected State key laboratory Inner Mongolia University of Science and Technology School of Rare Earth Inner Mongolia University of Science and Technology

Melting method was used to obtain La2Mg17 alloy, and then Ni powder was added by mechanical alloying method. The kinetics of hydriding process and electrochemical properties of La2Mg17-X wt.%Ni （x=0, 50, 100, 150, 200） composites were investigated. X-ray diffraction （XRD） and scanning electron microscopy （SEM） analyses showed that the crystal structure of composite alloy gradually transformed into amorphous phase by the effect of ball milling and Ni powders. The research of hydrogen absorption properties found that La2Mg17-50 wt.%Ni reached the highest hydrogen absorption than other alloys with more addition of Ni content, reached to 5.796 wt.% at 3 MPa, and up to 5.229 wt.% merely in 2 min, which revealed that the amorphous phase reduced the H occupation of the lattice clearance, resulting in the decline of hydrogen absorption capacity. The electrochemical tests indicated that the maximum discharge capacity increased to 353.1 mAh/g at 30 ℃, however, the cycle stability decreased considerably./~ series of ki- netic measurements demonstrated that the controlling steps of electrochemical process of La2Mg17-x wt.%Ni alloys transferred from hydrogen diffusion on alloy bulk （x=50, 100） to hydrogen diffusion on both alloy bulk and surface （x=150, 200）.

关键词： hydrogen storage materials ball-milling electrochemical properties amorphous rare earths

Experimental study and theoretical analysis of fluid resistance in porous media of glass spheres

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Chinese Physics B 2017年第7期26卷 228-233页

作者：王彤郑坤灿贾宇鹏付承鹭龚志军武文斐 Institute of Energy and Environment inner mongolia University of Science and Technology inner mongolia key laboratory of Integrated Exploitation of bayan obo multi-metallic resourcesinner mongolia University of Science and Technology

Porous media have a wide range of applications in production and life, as well as in science and technology. The study of flow resistance in porous media has a great effect on industrial and agricultural production. The flow resistance of fluid flow through a 20-mm glass sphere bed is studied experimentally. It is found that there is a significant deviation between the Ergun equation and the experimental data. A staggered pore-throat model is established to investigate the flow resistance in randomly packed porous media. A hypothesis is made that the particles are staggered in a regular triangle arrangement. An analytical formulation of the flow resistance in random porous media is derived. There are no empirical constants in the formulation and every parameter has a specific physical meaning. The formulation predictions are in good agreement with the experimental data. The deviation is within the range of 25%. This shows that the staggered pore-throat model is reasonable and is expected to be verified by more experiments and extended to other porous media.

关键词： porous media random packing staggered pore-throat model flow resistance

Spray Deposition Behavior and Numerical Simulation of Growth of Tubular Preform in Spray Forming Process

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Journal of Iron and Steel Research International 2012年第2期19卷 28-35页

作者： XIANG Jin-zong ZHANG Yin FAN Wen-jun WANG Ping HE You-duo inner mongolia key laboratory for utilization of bayan obo multi-metallic resources： Elected State keylaboratory Inner Mongolia University of Science and Technology Baotou 014010 Inner Mongolia China Anhui Shoukuang-Dachang Metal Materials Co Ltd Luran 237400 Anhui China

Analysis on the deposition behavior of spray on deposition surface was made and an optimization method for the movement parameters （u, ω） of substrate was obtained. Simultaneously, a mathematical model of growth of tubular preform, specifically aimed at the kind of atomizer that is fixed and with a tilt angle was established. By in- tegrating the optimization method and the mathematical model, the growth process and shape of preform were simu- lated. The results show that the tilt angle of atomizer plays an important role on the dimensions and shapes of tubular preforms and it can provide a guidance for the development of spray forming equipment.

关键词： spray deposition behavior parameters optimization tubular preform~ growth process

Magnetic and transport properties of bilayered manganites La_(1.2)Sr_(1.8)Mn_(2-x)Ga_xO_7(x=0,0.08)

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Chinese Physics B 2011年第8期20卷 408-410页

作者：郑琳周敏赵建军成昭华张向群邢茹张雪峰鲁毅 Department of Physics Baotou Normal University State key laboratory of Magnetism and Beijing National laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences inner mongolia key laboratory for utilization of bayan obo multi-metallic resources:Elected State key laboratory Inner Mongolia University of Science and Technology

The magnetic and electrical properties of nonmagnetic Ga＋3 ion substitution for Mn site are investigated in the bilayer manganite La1.2Sr1.8Mn2-xGaxO7. When the Mn is substituted by Ga, the ferromagnetic property obviously weakens, the magnetic transition temperature decreases and a spin-glass behaviour occurs at low temperature. Meanwhile, doping causes the resistivity to dramatically increase, the metal-insulator transition temperature to disappear, and a greater magneto-resistance effect to occur at low temperature. These effects result from the fact that Ga substitution dilutes the magnetic active Mn-O-Mn network and weakens the double exchange interaction, and further suppresses ferromagnetic ordering and metallic conduction.

关键词： magnetic property electrical property magnetoresistance effect metal-insulator transition

Three-and two-dimensional calculations for the interface anisotropy dependence of magnetic properties of exchange-spring Nd2Fe(14)B/α-Fe multilayers with out-of-plane easy axes

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Chinese Physics B 2020年第3期29卷 389-395页

作者： Qian Zhao Xin-Xin He Francois-Jacques Morvan Guo-Ping Zhao Zhu-Bai Li inner mongolia key laboratory for utilization of bayan obo multi-metallic resources Elected State Key LaboratoryDepartment of Applied PhysicsCollege of ScienceInner Mongolia University of Science and TechnologyBaotou 014010China Ningbo Institute of Industrial Technology Chinese Academy of SciencesNingbo 315201China College of Physics and Electronic Engineering Sichuan Normal UniversityChengdu 610066China

Hysteresis loops,energy products and magnetic moment distributions of perpendicularly oriented Nd2Fe(14)B/α-Fe exchange-spring multilayers are studied systematically based on both three-dimensional(3D)and one-dimensional(1D)micromagnetic methods,focused on the influence of the interface *** calculated results are carefully compared with each *** interface anisotropy effect is very palpable on the nucleation,pinning and coercive fields when the soft layer is very ***,as the soft layer thickness increases,the pinning and coercive fields are almost unchanged with the increment of interface anisotropy though the nucleation field still monotonically *** interface anisotropy decreases the maximum energy products and increases slightly the angles between the magnetization and applied *** magnetic moment distributions in the thickness direction at various applied fields demonstrate a progress of three-step magnetic reversal,i.e.,nucleation,evolution and irreversible motion of the domain *** above results calculated by two models are in good agreement with each ***,the in-plane magnetic moment orientations based on two models are *** 3D calculation shows a progress of generation and disappearance of vortex state,however,the magnetization orientations within the film plane calculated by the 1D model are *** results suggest that negative interface anisotropy is necessarily avoided experimentally.

关键词： micromagnetics interface anisotropy Nd2Fe(14)B/α-Fe multilayers magnetic properties