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Meng Y.,Lanzhou University of Technology | Zhu F.,Lanzhou University of Technology | Zhu F.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals | Hua Y.,Kunming University of Science and Technology
Russian Journal of Non-Ferrous Metals | Year: 2017

Synergistic effect of FeS and ZnS content on the separation of lead and antimony for PbS–Sb2S3–ZnS–FeS quaternary system under water vapor atmosphere has been studed in this paper. The results indicate that FeS can and ZnS can inhibit the volatilization of PbS. Inhibition effect of FeS is superior to that of ZnS to the volatilization of PbS. As to Sb2S3, FeS can inhibite the volatilization of Sb2S3, but ZnS can promote the volatilization of Sb2S3. Inhibition effect of FeS is superior to that of ZnS to the volatilization of Sb2S3. © 2017, Allerton Press, Inc.


Zhang Q.,Lanzhou University of Technology | Zhang Q.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals | Mei J.,Lanzhou University of Technology | Wang X.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals | And 3 more authors.
Electrochimica Acta | Year: 2014

A new facile approach to the surface modification of LiNi0.5Mn1.5O4 by lithium polyacrylate coating is demonstrated. This strategy is based on mild polymer electrolyte coating from aqueous lithium polyacrylate solution. The LiNi0.5Mn1.5O4 (LNM) and 1% PAALi coated LNM (LNM@1%PAALi) are characterized by XRD, SEM, TEM, ICP-OES, galvanostatic charge-discharge tests and electrochemical impedance spectra (EIS). XRD and SEM results indicate that there are no clear difference between LNM and LNM@1%PAALi. HRTEM results indicate PAALi is uniformly coated on LiNi0.5Mn1.5O4. ICP-OES results indicate that PAALi coating can effectively prevent the Ni ions and roughly prevent Mn ions dissolving from LiNi0.5Mn1.5O4 cathode materials. Galvanostatic charge-discharge tests show that the discharge capacity of LNM@1%PAALi reaches up to 131.5 mAh g-1 at 0.2 C and the value is still as high as 101.5 mAh g-1 at 12 C. In addition, LNM@1%PAALi shows high coulombic efficiency and retains 90.0% of its initial discharge capacity after 200 cycles. EIS proves that LNM@1%PAALi cells has distinct lower ohmic resistance of the electrolyte. SEM of the cycled electrodes implies that PAALi can promote the formation of valid SEI film, being favor of the compatibility between LNM and electrolyte. © 2014 Elsevier Ltd. All rights reserved.


Xin H.-Q.,Lanzhou University of Technology | Hou X.-G.,Lanzhou University of Technology | Hou X.-G.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals | Han X.-X.,CAS Lanzhou Institute of Chemical Physics
Faguang Xuebao/Chinese Journal of Luminescence | Year: 2015

By using liquid exfoliation method with sonication in appropriate stripping solvent, ultrasonic time, ultrasonic power, MoS2 hybrid-nanosheets suspension with different lateral dimension and uniform dispersion nanosheets were obtained. Under 360 nm excitation, the suspension shows both the luminescence properties of monolayer MoS2 and small MoS2 nanoparticles. The strongest peak of the sample is centered at 512 nm, and shows obvious blue-shifted compared with that of monolayers MoS2 exfoliated by the micromechanically cleavage method. The blue-shifted luminescence is mainly caused by the strong quantum confinement effect of the MoS2 hybrid nanosheets which produced in horizontal dimension as well. ©, 2015, Chines Academy of Sciences. All right reserved.


Li Y.M.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals | Huo X.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals
Advanced Materials Research | Year: 2014

Electroless silver plating on the surface of fly ash cenospheres was prepared by slowly adding the solution of AgNO3 into the mixed solution of D-glucose solution and alkaline solution after thermo-alkaline treatment. The morphology and composition of the silver-coated fly ash cenospheres composite powders were observed and analyzed by using SEM, EDS and XRD, and the influence of pH, loading quantity on silver plating was invested. The results revealed that, with the pH value of plating solution increasing, the precipitation of silver is improved, but led to self-accelerating decomposition if too high, and the influence of loading quantity on silver relative content and electro-conductivity of composite powders is very great. The silver shell of composite particles is even and compact when the pH value is 12.57 and the loading quantity is 4g/L, which resistivity can reach to 0.05Ω•cm. © (2014) Trans Tech Publications, Switzerland.


Zhang Q.,Lanzhou University of Technology | Mei J.,Lanzhou University of Technology | Wang X.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals | Guo J.,Lanzhou University of Technology | And 2 more authors.
Journal of Alloys and Compounds | Year: 2014

Spherical LiMn2O4 nanoparticles were successfully prepared via solution combustion synthesis by controlling calcinating temperature. XRD results indicate that high purity LiMn2O4 can be fabricated by calcinating the precursor above 600 °C. SEM results reflect that LiMn2O4 calcinated lower than 600 °C are composed of nanoparticles about 100 nm. Therefore, LiMn2O4 calcinated at 600 °C possess high purity and nanoparticles, which ensure the most excellent electrochemical performance among the precursor as well as LiMn2O4 calcinated at 500 °C, 600 °C and 700 °C. LiMn2O4 calcinated at 600 °C even can deliver a capacity of 103.8 mA h g-1 at 10 C, which is the 83.6% of the capacity at 0.2 C. It also displays excellent capacity retention ratio of 95.1% for 100 cycles at constant current rate of 1 C. © 2014 Elsevier B.V. All rights reserved.


Wang X.,Lanzhou University of Technology | Fan D.,Lanzhou University of Technology | Fan D.,State Key Laboratory of Advanced Processing and Recycling of Non Ferrous Metals | Huang J.,Lanzhou University of Technology | And 3 more authors.
International Journal of Heat and Mass Transfer | Year: 2015

Based on a unified three dimension mathematical model developed in previous studies, arc plasma and weld pool in double electrodes tungsten inert gas welding are numerically investigated with emphasizes on electrode separation. The effects of small amounts of oxygen (4%) added to shielding gas on the weld pool dynamics are studied by neglecting its effect on the arc plasma reasonably. The distributions of current density, heat flux and shear stress at the anode are analyzed for various electrode separations. It is found that the electrode separation has a significant influence on the flow and temperature fields of arc plasma while has insignificant effect on the maximum temperature of it. With increase in the electrode separation, the distributions of current density, heat flux and temperature at the anode range from one peak profiles to two-peak profiles, while total heat input to the anode changes little. As the electrode separation increases, the extension of the weld pool alters from the direction vertical to the line through the two electrodes to that parallel to the line. The constriction of the weld pool width and increase of the weld pool depth are induced by the reversed heat convection in the weld pool due to small amounts addition of the oxygen. With a certain electrode separation, there exist two peak temperatures at the anode and local inward flow in the weld pool with argon shielding, while local outward flow appears with oxygen addition. © 2015 Elsevier Ltd. All rights reserved.


Wang X.,Lanzhou University of Technology | Fan D.,Lanzhou University of Technology | Fan D.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals | Huang J.,Lanzhou University of Technology | And 3 more authors.
Journal of Physics D: Applied Physics | Year: 2014

A three-dimensional model containing tungsten electrodes, arc plasma and a weld pool is presented for double electrodes tungsten inert gas welding. The model is validated by available experimental data. The distributions of temperature, velocity and pressure of the coupled arc plasma are investigated. The current density, heat flux and shear stress over the weld pool are highlighted. The weld pool dynamic is described by taking into account buoyance, Lorentz force, surface tension and plasma drag force. The turbulent effect in the weld pool is also considered. It is found that the temperature and velocity distributions of the coupled arc are not rotationally symmetrical. A similar property is also shown by the arc pressure, current density and heat flux at the anode surface. The surface tension gradient is much larger than the plasma drag force and dominates the convective pattern in the weld pool, thus determining the weld penetration. The anodic heat flux and plasma drag force, as well as the surface tension gradient over the weld pool, determine the weld shape and size. In addition, provided the welding current through one electrode increases and that through the other decreases, keeping the total current unchanged, the coupled arc behaviour and weld pool dynamic change significantly, while the weld shape and size show little change. The results demonstrate the necessity of a unified model in the study of the arc plasma and weld pool. © 2014 IOP Publishing Ltd.


Fan D.,Lanzhou University of Technology | Fan D.,State Key Laboratory of Advanced Processing and Recycling of Non Ferrous Metals | Huang Z.-C.,Lanzhou University of Technology | Huang J.-K.,Lanzhou University of Technology | And 4 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2015

A three-dimensional (3D) numerical analysis model of tungsten inert gas welding arc interacting with an anode material is presented based on the local thermodynamic equilibrium assumption and taking the behavior of metal vapor into account. The thermodynamic parameters and transport coefficients of plasma arc are dependent on the local temperature and metal vapor concentration. A second viscosity approximation is used to express the diffusion coefficient which describes the metal vapor diffuse in the argon plasma. The weld pool dynamic is described by taking into account the buoyancy, Lorentz force, surface tension, and plasma drag force. The temperature coefficient of the surface tension at the weld pool surface is considered in two ways: one is taken as a function of temperature with only oxygen being the active component, and the other is taken as a constant value. The distributions of temperature field and velocity field of arc plasma and weld pool, metal vapor concentration and current density in the arc plasma are investigated by solving the Maxwell equations, continuity equation, momentum conservation equation, energy conservation equation and the components of the transport equation. The influence of metal vapor on arc plasma behavior and that of arc plasma on the weld pool are studied and compared with the non-metal vapor results. It is shown that the distribution of Fe vapor concentrates around the weld pool surface. Metal vapor has obvious shrinkage effect on arc plasma, and weak influences on velocity and potential of the arc plasma. In addition, the metal vapor has a weak effect on the distributions of velocity and shear force on the weld pool surface and no obvious influence on the molten pool shape. We test two different methods to illustrate this point in the case with or without metal vapor. The method used for a variable temperature coefficient of surface tension allows the prediction of a depth-to-width ratio and weld pool shape in agreement with experimental result when taking the behavior of metal vapor into account. The results in this paper, obtained by simulation are in good agreement with experimental results and also with the simulation results by some other authors. ©, 2015, Chinese Physical Society. All right reserved.


Chen Y.,Lanzhou University of Technology | Chen Y.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals | Li W.,Lanzhou University of Technology | Zhang M.,Lanzhou University of Technology | And 4 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2016

Possible geometrical structure, relative stabilities of Mg3N2Hm (m=1~4) and (Mg3N2)nHm (n=2~4, m=1~2) clusters were studied by a density functional theory B3LYP method with 6-311G* basis set level. For the most stable isomers of Mg3N2Hm (m=1~4) and (Mg3N2)nHm (n=2~4, m=1~2) clusters, the electronic structure, bonding characteristics, charge distribution, vibrational properties and relative stabilities were analyzed. When the adsorbed H atoms are less than N atoms, it mainly forms -NH group. And then some H atoms are adsorbed by the -NH groups and it forms -NH2 groups while some other H atoms are adsorbed by Mg to form MgH with all the N atoms bond as -NH. H atom is easily adsorbed on N atom which is projecting and contains the lone pair electrons. Due to the repulsion between the lone pair electrons, the adsorption positions of H atoms are away from each other. The N-H bond in clusters shows covalent interaction, while the Mg-H shows ionic bond interaction. The properties of-NH and -NH2 group are consistent with that of crystals, so the cluster can describe the behavior of the hydrogen storage in crystals. © 2016, Science Press. All right reserved.


Song H.-M.,Lanzhou University of Technology | Ran F.,Lanzhou University of Technology | Ran F.,State Key Laboratory of Advanced Processing and Recycling of Non ferrous Metals | Fan H.-L.,Lanzhou University of Technology | And 5 more authors.
Gongneng Cailiao/Journal of Functional Materials | Year: 2015

This article reported the electrochemical performance of a microspheres carbon/MnO2(CMS/MnO2) composite prepared by an in-situ self-limiting deposition method under hydrothermal condition. The morphologies and structures of the prepared materials were characterized by scan electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermo gravimetric analysis (TGA), and the electrochemical behaviors were tested by means of cyclic voltammetry (CV), charge-discharge tests and electrochemical impedance spectroscopy (EIS), respectively. The results reveal that MnO2 homogeneously grow onto the surface of CMS to form a hydrangea-like microstructure. MnO2 has a typical K-Birnessite-type crystal structure and the content of MnO2 in the composite is 62 wt% and a specific capacitance of 266 F/g was obtained. Upon the prolonged synthetic time, the specific capacitance of resultant CMS/MnO2 materials increased and then levels off, because MnO2 nanosheets coated and grown on the surface of CMS step by step. ©, 2014, Journal of Functional Materials. All right reserved.

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