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Influence of Different Surfactants on Morphology of Single Crystal Ce2O（CO3）2·H2O and Formation Mechanism

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Chinese Journal of Chemical Physics 2006年第3期19卷 269-272页

作者： Yan Mei Ye-bin Han zuo-ren nie College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China

Three kinds of ultra-fine Ce2O（CO3）2·H2O powders with different morphologies were prepared by adding CTAB, PEG19000 and OP-10 to a solution of Ce2O（NO3）3·6H2O and urea according to the principle and the characteristics of the homogeneous precipitation method. The products were characterized by TEM and XRD. The results showed that the precursor was a single crystal, and that different surfactants had different influences on the morphology of the products. The cationic surfactant CTAB had little effect on crystal morphology merely reducing its size. Nonionic surfactants PEG19000 and OP-10 are both able to change the crystal morphology to a much greater extent. Adding PEG19000 produces an array of rod-like particles with ordered formation and uniform dimension. Meanwhile, in the system of OP-10, a sort of flower-like pattern with a dispersed center can be prepared. The formations of ultra-fine Ce2O（CO3）2·H2O powders with different morphologies occured because of the mechanism of formation and grain growth.

关键词： Surfactant Homogeneous precipitation Single crystal Morphology Mechanism

‘‘Complexation–precipitation'' metal separation method system and its application in secondary resources

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Rare Metals 2014年第4期33卷 369-378页

作者： zuo-ren nie Li-Wen Ma Xiao-Li Xi College of Materials Science and Engineering Beijing University of Technology

Recovery processes of secondary resources usually encounter problems because of the diverse com- positions of wastes. To enhance the applicability of tradi- tional hydrometallurgical process toward secondary resources, the adjustment of components is necessary. In traditional hydrometallurgical separation, precipitation and complexation are extensively used. However, their com- bination as a specific metal separation method has not yet been studied in detail. This approach is very promising for solving problems caused by changeable components during recycling processes of secondary resources. This paper reviews the effects of precipitation and complexation in metal separation processes, and a metal separation method system of ＂complexation-precipitation＂ developed to adjust the components of secondary resources is introduced.

关键词： Secondary resources Complexation-precipitation Method system Metal separation

Applications of molten salt and progress of molten salt electrolysis in secondary metal resource recovery

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International Journal of Minerals,Metallurgy and Materials 2020年第12期27卷 1599-1617页

作者： Xiao-li Ming Feng Li-wen Zhang zuo-ren nie College of Materials Science and Engineering Key Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaBeijing University of TechnologyBeijing 100124China National Engineering Laboratory for Industrial Big-data Application Technology Beijing University of TechnologyBeijing 100124China

Molten salt is an excellent medium for chemical reaction,energy transfer,and *** salt innovative technologies should be developed to recover metals from secondary resources and reserve metals from primary natural *** these technologies,molten salt electrolysis is an economic and environment-friendly method to extract metals from waste *** the perspective of molten salt characteristics,the application of molten salts in chemistry,electrochemistry,energy,and thermal storage should be comprehensively *** review discusses further directions for the research and development of molten salt electrolysis and their use for metal recovery from various metal wastes,such as magnet scrap,nuclear waste,and cemented carbide *** is placed on the development of various electrolysis methods for different metal containing wastes,overcoming some problems in electrolytes,electrodes,and electrolytic *** focus is given to future development directions for current associated processing obstacles.

关键词： molten salt application molten salt electrochemistry resource recycling cemented carbide scrap

Hot pressing sintering process and sintering mechanism of W-La_(2)O_(3)-Y_(2)O_(3)-ZrO_(2)

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Rare Metals 2021年第7期40卷 1949-1956页

作者： Bao-Gang Fu Jian-Can Yang Zhi-Kun Gao zuo-ren nie College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China

The W-La_(2)O_(3)-Y_(2)O_(3)-ZrO_(2)materials were prepared by vacuum hot pressing sintering *** microstructure was characterized by scanning electron microscopy(SEM).The effects of sintering temperature,sintering pressure,holding time and heating rate on relative density,hardness and microstructure were *** sintering activation energy of the powder was *** on the result,the best sintering parameters by vacuum hot pressing sintering are as follows:sintering temperature of 1600℃,sintering pressure of 60 MPa and holding time of 60 *** heating rate is 10℃·min^(-1)from room temperature to 1000℃and 4℃·min^(-1)from1000 to 1600℃.Using this process,the grain size is about3 lm in diameter with relative density at 99.7%,and the hardness is HV *** sintering characteristic index(n)of the specimen is 4,and the sintering mechanism mainly depends on the diffusion from the surface to the intragranular in the volume *** sintering activation energy of W-La_(2)O_(3)-Y_(2)O_(3)-ZrO_(2)material is286.2 k J·mol^(-1),which indicates that the powder has higher activity in sintering process.

关键词： W-La_(2)O_(3)-Y_(2)O_(3)-ZrO_(2) Hot pressing sintering Relative density Tungsten electrode Sintering mechanism

Improvement in oxidation resistance of Cantor alloy through microstructure tailoring

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China Foundry 2022年第6期19卷 503-510页

作者： Bao-lin Pang Man Wang Yue-gang Shen Xiao-li Xi zuo-ren nie Collaborative Innovation Center of Capital Resource-Recycling Material Technology Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China Key Laboratory of Advanced Functional Materials Ministry of EducationBeijing University of TechnologyBeijing 100124China National Engineering Laboratory for Industrial Big-data Application Technology Beijing University of TechnologyBeijing 100124China

A method of improving the oxidation resistance of Cantor alloy through microstructure tailoring was *** with distinctive microstructures were achieved by different annealing treatments on the cold-rolled Cantor *** test was then carried out on the various annealed samples at 800°C for 24 h in *** oxidation behavior was evaluated in terms of oxidation rate,surface and cross-section microstructure *** stratified oxide layers including outer Mn_(2)O_(3) and inner Cr_(2)O_(3) were observed in all the annealed samples,the thickness of Mn_(2)O_(3) and Cr_(2)O_(3) layers was ***,the samples exhibited different oxidation *** results indicate that the oxidation resistance of various annealed samples is closely related with grain size as well as twin density.

关键词： Cantor alloy annealing temperature grain size twins oxidation behavior

Comprehensive recovery of W,V,and Ti from spent selective reduction catalysts

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Rare Metals 2023年第10期42卷 3518-3531页

作者： Li-Wen Ma Xiao-Li Xi Jia-Peng Chen Fan Guo Zi-Jie Yang zuo-ren nie Key Laboratory of Advanced Functional Materials Ministry of EducationFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing100124China Collaborative Innovation Center of Capital Resource-Recycling Material Technology Beijing University of TechnologyBeijing100124China National Engineering Laboratory for Industrial Big-Data Application Technology Beijing University of TechnologyBeijing100124China

In this study,spent WO_(3)/V_(2)O_(5)-TiO_(2) catalysts used for selective catalytic reduction were treated by a hydrometallurgical process to comprehensively recover valuable metallic elements,such as W,V,and *** and Si impurities were preferentially removed by selective micro wave-assisted alkali leaching.W and V were leached by enhanced high-pressure leaching with efficiencies estimated at 95% and 81%.The leaching of W and V followed the nuclear shrinkage model controlled by the combination of product layer diffusion and interfacial chemical reaction.A synergistic extraction was applied to separate W and V using an extractant mixture of di-(2-ethylhexyl)phosphoric acid P204 and the primary amine *** extraction efficiencies of V and W reached 86.5% and 6.3%,respectively,with a separation coefficient(V/W) of *** product was precipitated after extraction to yield ammonium paratung state(APT) and NH_(4)VO_(3).The TiO_(2)catalyst carrier residue meets commercial specifications for *** comprehensive recovery process with the characteristics of high-pressure leaching and synergistic extraction realizes the resourceful utilization of the spent catalysts.

关键词： Spent selective catalytic reduction(SCR)catalysts Microwaveleaching Pressure leaching Synergistic extraction Comprehensive recovery

Plasticity and microstructure evolution of W-CeO2 rods with different short-duration pulse currents

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Rare Metals 2017年第12期36卷 981-986页

作者： Wen-Guang Zhu Jian-Can Yang Jie Cao Lin Huang Yu-Chen Xi zuo-ren nie School of Materials Science and Engineering Beijing University of Technology Beijing 100124 China

To improve the formability of W-rare earth electrode, the influence of high-energy pulse on the plasticity property of W-CeOrods was investigated. The effects of current density(J), pulse width(tw), frequency(f), and strain rate on the plasticity of W-CeOrods were discussed in detail. Results of tensile tests show that the W-CeOrods applied with the electrical pulses obtain a maximum percentage total elongation at fracture(9.65 %), increased by118.7 % compared to that without pulses. This is owing to both the heat effect and the interaction of current between dislocations and rare earth additions. Electron back scattered diffraction(EBSD)-generated grain boundary(GB) maps suggest that the length of low-angle grain boundaries composed of high-density dislocations decreases after deformation while applying the pulse current. This demonstrates that the short-duration pulsed current enhances the mobility of dislocations. Scanning electron microscopy(SEM) images of the rods after deformation with the pulse current show that the long fiber-shaped additions become discontinuous,which could reduce the stress concentration and hinder the crack propagation.

关键词： Pulse current Plasticity W-CeO_2 rod Lowangle grain boundary

Regulation of morphology and visible light-driven photocatalysis of WO_(3)nanostructures by changing pH

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Rare Metals 2021年第7期40卷 1738-1745页

作者： You-Shu Fan Xiao-Li Xi Yang-Si Liu zuo-ren nie Lin-Yan Zhao Qing-Hua Zhang College of Materials Science and Engineering Key Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaBeijing University of TechnologyBeijing 100124China National Engineering Laboratory for Industrial Big-data Application Technology Beijing University of TechnologyBeijing 100124China

The controlled preparation of hexagonal tungsten trioxide(h-WO_(3))nanostructures was achieved by adjusting the pH of the precursor *** effect of the pH on the morphology,elemental composition,and photocatalytic performance of the samples was characterized via X-ray diffraction(XRD),scanning electron microscopy,energy dispersive X-ray spectroscopy,and Raman ***-visible(UV-Vis)spectra were used to evaluate the absorbance and the photocatalytic performance of methylene ***(PL),electrochemical impedance spectroscopy,photocurrent response and Brunauer-Emmett-Teller(BET)were used to study the optical properties,electrical performance,and specific surface area of the WO_(3)-nanostructures,*** results indicate that the WO_(3) nanorods prepared at pH=1.0 exhibit the highest photocatalytic performance(87.4%in 1 h),whereas the WO_(3) nanoblocks prepared at p H=3.0 show the *** photocatalytic performance of the one dimensional(1 D)-nanorods can be attributed to their high specific surface area and charge transfer *** h-WO_(3) nanostructures were synthesized via a simple method and without a capping *** show an excellent photocatalytic performance,which is promising for their application in environment purification.

关键词： h-WO_(3) Morphology pH Photocatalysis Charge transfer Optoelectrical properties

Mechanical properties and corrosion behavior of a new RRA-treated Al-Zn-Mg-Cu-Er-Zr alloy

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Rare Metals 2023年第2期42卷 672-679页

作者： Jun-Tai Lu Hui Huang Hao Wu Sheng-Ping Wen Kun-Yuan Gao Xiao-Lan Wu zuo-ren nie School of Materials Science and Engineering Beijing University of TechnologyBeijing100124China

The effect of various retrogression and re-aging(RRA)treatments on mechanical properties and corrosion behavior of a new type Al-Zn-Mg-Cu-Er-Zr alloy was investigated by microhardness testing,tensile testing,intergranular corrosion(IGC)and exfoliation corrosion(EXCO)*** results show that the RRA treatment can effectively improve the IGC and EXCO resistance with less strength sacrificing because the grain interior precipitates and the grain boundary precipitates are similar to that of T6 temper and T73 ***,as the microhardness of the retrogressed alloy reaches the peak value during the retrogression at 170℃,the corresponding RRA-treated alloy possesses the better strength,but the corrosion resistance is poor in comparison with that of the retrogression at 190℃.The optimal combination of strength,IGC and EXCO resistance is obtained after retrogression at 180℃for 60 ***,for different heat treatment tempers,the corresponding micros true tural evolution of the precipitates including Al_(3)(Er,Zr)particles was also discussed in detail.

关键词： Al-Zn-Mg-Cu-Er-Zr alloy RRA treatment Mechanical properties Corrosion behavior