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Migration behavior, separation and recycling of rare earth during thermal decomposition of Zhijin phosphorus ore

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Journal of Rare Earths 2018年第11期36卷 1205-1211页

作者： Dengpan Nie Yu Zhang An Xue Mingyang Zhu Jianxin Cao College of Resource and Environmental engineering Guizhou University Guiyang 550025 China guizhou institute of metallurgical aud chemical engineering Guiyang 550002 China School of Chemistry and chemical engineering Guizhou University Guiyang 550025 China

Zhijin phosphorus ore is a moderate and low-grade phosphorus rare-earth ore contained in mines. The separation and extraction of associated rare earth are important research topics. In this study, the migration behavior of rare earth during the thermal decomposition of Zhijin phosphorus ore and the separation and extraction of rare earth in phosphorus slag are discussed systematically. During the thermal decomposition process of phosphorus ore, almost all of the associated rare earth enters into the phosphorus slag phase but does not enter into the ferrophosphorus or gas phases. Amorphous calcium metasilicate and calcium fluosilicate are major components of phosphorus slag, and rare earth mainly exists as a calsil solid solution. Hydrochloric acid was used for acidolysis of the phosphorous slag. Under the following conditions, 96% of the rare earth in the phosphorous slag can be dissolved in the acidolysis solution： acid excess coefficient of 1.5, reaction time of 50 min and reaction temperature of 50℃. The rare earth in the acidolysis solution was separated and recycled using oxalic acid as a precipitator and NaOH as a pH modifier. At pH of 1.7, rare-earth-enriched matter with rare-earth content of 2.1 wt% was obtained, and the recovery of the rare earth was 88%.

关键词： Zhijin phosphorus ore Rare earth Thermal decomposition Migration behavior Separation

Enhanced photothermal dehydration of methanol over W18O49/Au/SAPO-34 catalysts with broadened light absorption

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Rare Metals 2024年第3期43卷 1139-1152页

作者： Ya-Qin Tang Meng-Xia Yan Chang-Qian Lu Shao-Yuan Li Kui-Xian Wei Tao Qu Wen-Hui Ma Yong-Nian Dai Kong-Zhai Li Da-Jun Luo Xue-Liang Zhang Yi-Ke Liu Faculty of metallurgical and Energy engineering Kunming University of Science and Technology School of Materials and Energy engineering Guizhou Institute of Technology

Methanol-to-olefins(MTO) process is one of the most critical pathways to produce low carbon olefins.Typically,the reaction is driven by thermal catalysis,which inevitably needs to consume large amounts of fossil fuel.Developing a new technique to substitute for the fuel burning is urgent for MTO process to improve the industry prospects and sustainability.Herein,we report a novel W18O49/Au/SAPO-34(W/Au/S),a multifunctional photothermal catalyst for the MTO reaction.A high methanol conversion was achieved under xenonum(Xe) lamp irradiation,yielding methyl ether(ME) and ethylene as the main products.The optimized W/Au/S catalysts showed ethylene yield as high as 250 μmol in 60 min,which was 2.5 times higher than that of Au/SAPO-34.The physiochemical characterization revealed that the SAPO-34 molecular sieves were surrounded by Au and W18O49nanoparticles,which exhibited a strong localized surface plasmon resonance excitation around 540 nm and light absorption beyond 500 nm.The multifunctional catalysts showed a strong photothermal effect,arising from the broadened light absorption of Au and W18O49nanoparticles,leading to a temperature as high as 250 ℃on the surface of the catalysts.Mechanism study showed that the superior ethylene selectivity of W/Au/S catalysts was attributed to the moderating acidic sites of W18O49for methanol dehydration to ethylene.This research may provide new insight for designing heterostructures to improve photo-to-chemical conversion performance and is expected to accelerate progress toward the excellent multifunctional photothermal catalysts with broad light absorption for methanol activation and C-C bond formation.

关键词： Methanol conversion Ethylene Photothermal catalysis W 18 O 49 Brønsted-acid

Agglomeration behavior of alumina inclusions and calcium aluminate inclusions on molten nickel-based superalloy surface

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Journal of Iron and Steel Research(International) 2023年第11期30卷 2318-2327页

作者： Rui-zhi Gao Lin-zhu Wang Chao-yi Chen Shu-feng Yang Xiang Li Yin Zhang School of Materials and Metallurgy Guizhou UniversityGuiyang550025GuizhouChina School of metallurgical and Ecological engineering University of Science and Technology BeijingBeijing100083China Department of Materials and Metallurgy engineering Guizhou Institute of TechnologyGuiyang550003GuizhouChina

Understanding the interactive forces of inclusions on the surface of molten nickel-based superalloys and finding methods to disperse these inclusions help improve performance and service life.The aggregation behavior of aluminum oxide(Al_(2)O_(3))and calcium aluminate inclusions with different sizes and spacings on the surface of molten nickel-based superalloys was observed in-situ using a high-temperature confocal laser scan microscope.The attractive force acted on Al2O3 inclusions with radii of 3.5-6μm was found ranging from 6.2×10-18 to 3.6×10-15 N,and that of CaO·2Al2O3(CA2)inclusions with radii of 3-5.5μm ranging from 3.5×10-19 to 8.3×10-15 N.The capillary force acted on inclusions on the surface of nickel-based superalloy was calculated based on the Kralchevsky-Paunov model and investigated as a function of inclusion size,spacing,and composition.The calculated results were in the same trend as the experimental results.The capillary force acted on inclusions was also affected by their contact angle,the density,surface energy,and oxygen content of the molten alloy.It decreased with increasing alloy density and decreasing contact angle between inclusion with alloy.Thus,the attractive force acted on Al2O3 inclusions was smaller on the surface of molten nickel-based superalloy than that of molten steel.Decreasing the oxygen content in the molten nickel-based alloy could increase its surface energy,and the attractive force acted on the inclusions would decrease.When the oxygen content in the molten nickel-based alloy decreased from 0.05 to 0.0001 wt.%,the capillary force acted on the Al2O3 inclusions decreased from 1.7×10-18 to 3.6×10-19 N,reduced by 79%(1.4×10-18 N).

关键词： Inclusion Nickel-based superalloy Capillary force Alumina Calcium aluminate

Optimization of iron and aluminum recovery in bauxite

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Journal of Iron and Steel Research(International) 2020年第3期27卷 310-318页

作者： Qian Long Jun-qi Li Chao-yi Chen Yuan-pei Lan Guo-ling Wei Department of metallurgical engineering College of Materials and MetallurgyGuizhou UniversityGuiyang 550025GuizhouChina guizhou Province Key Laboratory of metallurgical engineering and Process Energy Saving Guiyang 550025GuizhouChina

Recovering iron and aluminum efficiently is the key route to utilize low-grade high-iron bauxite.Aiming to optimize the iron separating process and elevate both Fe and Al recovery ratio,three different Fe-Al recovery processes with different magnetic roasting(R),Bayer leaching process(L)and magnetic separation(S)orders were investigated.The studied processes include bauxite leaching→red mud roasting→magnetic separation(L-R-S),bauxite roasting→magnetic separation→leaching(R-S-L)and bauxite roasting→leaching→magnetic separation(R-L-S).The iron recovery ratio,Fe2O3 content in iron concentration and the bauxite dissolution ratio of each process were investigated.Moreover,the optimizations of the leaching,roasting and magnetic separation conditions were studied.Results indicate that the R-S-L process should be an advisable order to recover both alumina and iron.In the three processes,the R-S-L route had the highest alumina dissolution ratio and iron recovery ratio,which was 86.20%and 69.58%,respectively,while the Fe2O3 content of the iron concentrate was 40.66%.

关键词： High-iron bauxite Magnetic roasting Magnetic separation Recovery ratio Dissolution ratio

Adsorption of Au(Ⅲ) by amino-modified monodispersed PGMA microspheres and deposition of gold nanoparticles

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Rare Metals 2018年第3期37卷 196-203页

作者： Fu-Chun Wang Jun-Mei Zhao Wan-Kun Wang Zi-Zheng Tong School of Materials and metallurgical engineering Guizhou Institute of Technology institute of Process engineering Chinese Academy of Sciences

Monodispersed poly（glycidyl methacrylate）（PGMA） microspheres with various amounts of amino groups（PGMA-NH2） were used to adsorb Au（Ⅲ） from simulated wastewaters. Gold nanoparticle-coated PGMA functional microspheres can be directly obtained via the adsorption process. The adsorption kinetics follows pseudo-second model, and 10 min is enough for reaching at equilibrium. The adsorption isotherm follows Langmuir model, and the adsorption amounts for Au（Ⅲ） are 8.25 and 21.75 mol·kg^-1 at 298 and 328 K, respectively. The relative separation coefficients between Au（Ⅲ）, Pt（Ⅵ）, Pd（Ⅱ）and Co（Ⅱ）, Cu（Ⅱ）; Ni（Ⅱ）, Fe（Ⅲ） are all higher than 100 when 1 〈 pH 〈 3. Furthermore, the characterization analysis of X-ray diffraction（XRD）, thermogravimetrydifferential scanning calorimetry（TG-DSC）, scanning electron microscopy-energy dispersive spectroscopy（SEM-EDS）, transmission electron microscopy（TEM） and Fourier transform infrared spectroscopy（FTIR） confirms that AuCl4^-has been reduced to Au^0 nanoparticles and deposited onto the surface of PGMA-NH2. The current work shows a good prospect for PGMA-NH2 to be a valid adsorbent for the recovery of gold and the possible fabrication of gold nanoparticles by reduction-deposition process without any reductant.

关键词： PGMA microspheres AuCl4^- Amino groups Adsorption Reduction-deposition Elemental gold

Ti掺杂的WO_(3)纳米片光阳极的能带调控和光电化学分解水性能

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Journal of Central South University 2022年第9期29卷 2968-2979页

作者：唐雅琴蒋迪王欢郑红烨任露军魏奎先马文会戴永年罗大军张学亮刘仪柯 Faculty of metallurgical and Energy engineering Kunming University of Science and TechnologyKunming 650093China School of Materials and Energy engineering Guizhou Institute of TechnologyGuiyang 550003China

氧化钨(WO_(3))是一种重要的光电化学分解水半导体,具有可见光响应好、无毒、稳定性好等优点,但低的电导率、高的起始电位以及缓慢的水氧化动力学等缺点也限制了其进一步应用。本文采用无晶种水热法在导电玻璃(FTO)上设计了一种钛掺杂的... 详细信息

氧化钨(WO_(3))是一种重要的光电化学分解水半导体,具有可见光响应好、无毒、稳定性好等优点,但低的电导率、高的起始电位以及缓慢的水氧化动力学等缺点也限制了其进一步应用。本文采用无晶种水热法在导电玻璃(FTO)上设计了一种钛掺杂的WO_(3)纳米片阵列,并研究了Ti掺杂浓度对光电化学分解水性能的影响。结果表明,在0.6 V(vs Ag/AgCl)的偏压下,Ti掺杂WO_(3)光电流密度最高,可达0.53 mA/cm^(2),比纯WO_(3)纳米片阵列的高110%。同时,Ti掺杂WO_(3)光电极的起始电位负移。X射线光电子能谱价带谱(XPS-VB)和紫外-可见吸收(UV-Vis)光谱显示,Ti掺杂WO_(3)光阳极的能带位置向上移动,导致了起始电位的负移。此外,电化学阻抗谱测试(EIS)表明,Ti掺杂WO_(3)光阳极的导电性显著增强,引起光生载流子的快速分离。研究成果有望提供一种高效、低成本光阳极的设计路线。

关键词： WO_(3) Ti掺杂光阳极能带调控表面载流子分离

Recent advances in multifunctional electrochromic energy storage devices and photoelectrochromic devices

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Science China Chemistry 2017年第1期60卷 13-37页

作者： Zhongqiu Tong Yanlong Tian Hongming Zhang Xingang Li Junyi Ji Huiying Qu Na Li Jiupeng Zhao Yao Li College of Materials and metallurgical engineering Guizhou Institute of Technology Guiyang 550003 China Center for Composite Materials and Structure Harbin Institute of Technology Harbin 150001 China School of Chemistry and chemical engineering Harbin Institute of Technology Harbin 150001 China guizhou Construction Science Research & Design institute Limited Company of China State construction engineering Corporation Guiyang 550006 China

Multifunctional devices integrated with electrochromism and energy storage or energy production functions are attractive because these devices can be used as an effective approach to address the energy crisis and environmental pollution in society today. In this review, we explain the operation principles of electrochromic energy storage devices including electrochromic supercapacitors,electrochromic batteries, and the photoelectrochromic devices. Furthermore, the material candidates and structure types of these multifunctional devices are discussed in detail. The major challenges of these devices along with a further outlook are highlighted at the end.

关键词：储能器件光电变色多功能设备电致变色能电存储设备能源危机能量存储

Electrical conductivity optimization of the Na3AlF6–Al2O3–Sm2O3 molten salts system for Al–Sm intermediate binary alloy production

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International Journal of Minerals,Metallurgy and Materials 2017年第9期24卷 1034-1042页

作者： Chun-fa Liao Yun-fen Jiao Xu Wang Bo-qing Cai Qiang-chao Sun Hao Tang institute of metallurgical and chemical engineering Jiangxi University of Science and Technology

Metal Sm has been widely used in making Al–Sm magnet alloy materials. Conventional distillation technology to produce Sm has the disadvantages of low productivity, high costs, and pollution generation. The objective of this study was to develop a molten salt electrolyte system to produce Al–Sm alloy directly, with focus on the electrical conductivity and optimal operating conditions to minimize the energy consumption. The continuously varying cell constant(CVCC) technique was used to measure the conductivity for the Na3AlF6–AlF3–LiF–MgF2–Al2O3–Sm2O3electrolysis medium in the temperature range from 905 to 1055°C. The temperature(t) and the addition of Al2O3(W(Al2O3)), Sm2O3(W(Sm2O3)), and a combination of Al2O3and Sm2O3into the basic fluoride system were examined with respect to their effects on the conductivity(κ) and activation energy. The experimental results showed that the molten electrolyte conductivity increases with increasing temperature(t) and decreases with the addition of Al2O3or Sm2O3or both. We concluded that the optimal operation conditions for Al–Sm intermediate alloy production in the Na3AlF6–AlF3–LiF–MgF2–Al2O3–Sm2O3system are W(Al2O3) + W(Sm2O3) = 3wt%, W(Al2O3):W(Sm2O3) = 7:3, and a temperature of 965 to 995°C, which results in satisfactory conductivity, low fluoride evaporation losses, and low energy consumption.

关键词： aluminium oxide samarium oxide molten salt electrical conductivity regression analysis Al–Sm intermediate alloy

Cerium oxide inclusion nucleation mechanism based on classical nucleation theory and two-step nucleation

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Journal of Rare Earths 2024年第4期42卷 793-802页

作者： Yutang Li Jun Wang Linzhu Wang Chaoyi Chen Shufeng Yang Junqi Li Xiang Li School of Materials and Metallurgy Guizhou UniversityGuiyang550025China State Key Laboratory of Public Big Data Guizhou UniversityGuiyang550025China School of metallurgical and Ecological engineering University of Science and Technology BeijingBeijing100083China Department of Materials&Metallurgy engineering Guizhou Institute of TechnologyGuiyang550003China

It is challenging to assess the mechanism responsible for the nucleation of inclusions in metals at high temperatures.The present work therefore systematically investigates the nucleation of cerium oxide inclusions according to classical nucleation theory and a two-step nucleation mechanism.The nucleation rates and nucleation radii of these inclusions are obtained,and the results demonstrate a considerable difference between theoretical and experimental values.On the basis of a two-step nucleation mechanism,(CeO_(2))_(n) and(Ce_(2)O_(3))_(n)(n=1-6)clusters were constructed and the thermodynamic properties of both these clusters and of cerium oxide nanoparticles were analyzed.In addition,the entropies and heat capacity changes of cerium oxides were determined using first principles calculations and are found to be consistent with literature data.The present data indicate that the cerium oxide inclusion nucleation pathway can be summarized as[Ce]+[O]→(CeO_(2))n/(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(2)→core(Ce_(2)O_(3)crystal)-shell((Ce_(2)O_(3))_(2) cluster)nanoparticles→(Ce_(2)O_(3))bulk.

关键词： Cerium oxide inclusion Classical nucleation theory Two-step nucleation mechanism First principles Rare earths