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Kong X.-F.,Kunming University of Science and Technology | Kong X.-F.,Central South University | Kong X.-F.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | Yang B.,Kunming University of Science and Technology | And 9 more authors.
Journal of Central South University | Year: 2014

The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as (3-Mercaptopropyl) triethoxysilane (MPTES) and (3-Amincpropyl) trithoxysilane (APTES). Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared (FI-IR) and X-ray photoelectron spectroscopy (XPS). The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2+, Cu2+, Hg2+, Cd2+ and Zn2+ ions in aqueous solutions. The results show that the (3-Mercaptopropyl) triethoxysilane functionalized silica nanoparticles (SiO2-MPTES) play an important role in the selective adsorption of Cu2+ and Hg2+, the (3-Amincpropyl) trithoxysilane (APTES) functionalized silica nanoparticles (SiO2-APTES) exhibited maximum removal efficiency towards Pb2+ and Hg2+, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2+ at room temperature, respectively. © 2014, Central South University Press and Springer-Verlag Berlin Heidelberg.


Ren Y.,Kunming University of Science and Technology | Ren Y.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | Ma W.,Kunming University of Science and Technology | Ma W.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | And 7 more authors.
Vacuum | Year: 2014

A new route for degassing of molten aluminum alloys has been developed via the electromagnetic directional solidification. We evaluated the degassing feasibility and mechanism for the formation and evolution of the porosity. As expected, it enabled the migration of porosity to the upper end instead of the distribution in the whole sample. Furthermore, we investigated the effects of various pull-down rates, i.e., solidification rates on the degassing efficiency, porosity area fraction, and microstructure of alloys, etc. Clearly, the experimental results show that with the reducing of pull-down rates, the degassing efficiency increases and the porosity area fraction decreases, respectively. The lowest porosity area fraction is down to 0.08% under the 5 μm/s pull-down rate. Simultaneously, there are almost no porosity and other defects in the lower part of the final product. In conclusion, it offers an alternative method for degassing and possesses potential applications in aeronautic and space industry. © 2014 Elsevier Ltd. All rights reserved.


Dong Z.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | Dong Z.,Kunming University of Science and Technology | Dong Z.,Key Laboratory of Vacuum Metallurgy of Non Ferrous Metals of Yunnan Province | Xiong H.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | And 17 more authors.
Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology | Year: 2015

The feasibility of the enrichment of Sb2S3 from jamesonite by vacuum distillation was theoretically analyzed. The impact of the distillation conditions, including but not limited to the distillation temperature, holding time, pressure and contents of impurities, on the Sb2S3 volatilization rate was experimentally investigated with X-ray diffraction scanning electron microscopy, energy dispersive spectroscopy and conventional chemical analysis. The preliminary results show that depending on the distillation temperature, the enrichment of Sb2S3 from jamesonite by vacuum distillation is feasible. For example, as the distillation temperature increased, the Sb_ volatilization rate increased, but the Sb-content in the condensate changed in an increase-decrease mode. Distilled at 973 K and held for 30 min, the volatilization rate of Sb2S3 was found to be 92.84%, and the Sb-content in the condensate was estimated to be 68.47%. We suggest that the newly-developed vacuum distillation may outperform the conventional Sb-extraction from jamesonite by smelting because of the reduced environmental pollution, simplified operation and decreased power consumption. © 2015, Science Press. All right reserved.


Song B.,Kunming University of Science and Technology | Song B.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Song B.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | Jiang W.,Kunming University of Science and Technology | And 8 more authors.
Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology | Year: 2015

Separation of the Pb-Sb alloy by vacuum distillation, an environmental pollutantproduced in Pb and Sb smelting slag and in their consumption, was mathematically modeled, theoretically analyzed in thermodynamics and experimentally evaluated. The separation coefficient of Sb, contents of Pb and Sb in volitile and residue were estimated by plotting the vapor-liquid equilibrium composition diagram of the Pb-Sb alloy in 923~1373 K range. The calculated results show that vacuum distillation is capable of separating Pb and Sb. The influence of the distillation conditions, including the temperature, distillation time, contents of Pb and Sb in the raw Pb-Sb alloy, on the volatilization rates of Pb and Sb were experimentally investigated. Distilled at 5~10 Pa and 973 K for 30 min, the Sb-content was found to be 57.44% in the volatile and crude Pb-content was estimated to be 88.82% in residue. © 2015, Science Press. All right reserved.


Xiao Y.,Yunnan University | Chen X.,Yunnan University | Ma W.,Kunming University of Science and Technology | Ma W.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | And 5 more authors.
International Journal of Materials Research | Year: 2015

Large-area and oriented silicon nanowire arrays have been successfully fabricated through a two-step metal-assisted chemical etching process at room temperature. The effects of key fabrication parameters (AgNO3 concentration, Fe(NO3)3 concentration, and etching time) on the silicon nanowire nanostructure were carefully investigated. The Raman spectra of silicon nanowires prepared under different etching times have been recorded and analyzed. The porosity and length of the nanowire increases with the increase in AgNO3 concentration from 0.002 mol L-1 to 0.1 mol L-1, which indicates that the re-dissolved Ag+ ions would work as the main oxidative species and catalyze the vertical and lateral etching of nanowires, leading to silicon nanowire growth and porous structure formation. © Carl Hanser Verlag GmbH & Co. KG.


Lu Y.,Kunming University of Science and Technology | Lu Y.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Lu Y.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | Zhou Y.,Kunming University of Science and Technology | And 20 more authors.
Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology | Year: 2015

We theoretically addressed the mechanisms responsible for the carbothermic-chlorination of aluminum sub-oxide in vacuum. First, the influence of the reaction conditions, including but not limited to the reaction temperature and reaction pressure, was mathematically modeled and analytically calculated in thermodynamics to optimize the reaction conditions. Next, the first principle calculation by the plane-wave pseudo-potential scheme, based on density function theory (DFT), was performed to evaluate the stable molecular structures of Al2O and C, AlCl3 and C, Al2O and AlCl3 with C, respectively. Finally, the reaction, at 1760 K and 60 Pa, was simulated in ab initio molecular dynamics calculation. The simulated results show that the gaseous Al2O is decomposed more easily than A1C13 gas on C(001), and that most A1C1, decomposed from AlCl3, are adsorbed on C(001). We suggest that the calculated results may be of some basic and technological interest. ©, 2015, Science Press. All right reserved.


Kong X.,Kunming University of Science and Technology | Kong X.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | Yang B.,Kunming University of Science and Technology | Xiong H.,Kunming University of Science and Technology | And 9 more authors.
Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology | Year: 2014

A novel technique was developed to remove copper and tin from crude lead by vacuum distillation. The removal was theoretically and experimentally studied. The effects of the distillation conditions, particularly the distillation temperature and time, on the removal rate of copper and tin, direct recovery of lead, and recovery of silver were examined. The experimental results show that the removal rate of copper is close to 100%, the removal rate of tin is 98%, and the direct recovery of lead is also 98%, when distilled at a pressure from of 5 to 15 Pa and a temperature of 1323 K for 30 min. Moreover, the enriched silver was found to exist in the residue because silver is basically non-volatile. We suggest that vacuum distillation be a simple, clean, and effective technique to remove copper and tin from crude lead.


Lu Y.,Kunming University of Science and Technology | Lu Y.,Key Laboratory of Vacuum Metallurgy of Non ferrous Metals of Yunnan Province | Zhou Y.,Kunming University of Science and Technology | Zhou Y.,Key Laboratory of Vacuum Metallurgy of Non ferrous Metals of Yunnan Province | And 13 more authors.
Vacuum | Year: 2015

AlN chlorination route, in the present work, was proposed to extract Aluminum from aluminum nitride under vacuum. Density functional theory (DFT) were implemented to study the interaction of AlCl3 molecule and AlN (101¯0) surface. The results of DFT indicate that chemisorbed AlCl3 adsorption configuration was observed on the clean AlN (101¯0) surface after structure optimization, and adsorbed AlCl molecules were generated after 1 ps dynamic simulation time. The phase and composition of condensate were examined by means of XRD and EDS. It was found that 97.76 wt% of Al metal was obtained in the experiment B (in the presence of AlCl3), however, no condensate was collected in the experiment A (without AlCl3) at 1760 K under pressure of average 60 Pa. The results show that AlN chlorination route is an alternative Al production method from aluminum nitride. © 2015 Elsevier Ltd. All rights reserved.


Lu Y.,Kunming University of Science and Technology | Lu Y.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Lu Y.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | Zhou Y.,Kunming University of Science and Technology | And 23 more authors.
Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology | Year: 2015

The havior of AlCl2 in carbothermic-chlorination-disproportionation of Al2O in vacuum was theoretically analyzed. First, the impact of the reaction conditions on the chlorination was modeled and calculated with software HSC Chemistry 6.0 and Material Studio. The calculated results show that the chlorination of the reactants, including Al2O and C, Al4C3 and Al2O3, Al4O4C and C, is possible at 1760 K and 60 Pa, and that the disproportionation of AlCl2 occurs in the upper condensation-zone of the furnace. Next, the disproportionation of AlCl2 and the chlorination of Al2O and C were dynamically simulated, by the first-principles calculation of plane-wave pseudo-potential technology based on density function theory (DFT) and in ab initio molecular dynamics method, to optimize the atomic structures. The simulated results show that AlCl2 does form in carbothermic-chlorination-disproportionation of Al2O in vacuum. The AlCl, produced by the reaction of C and adsorbed AlCl2, remains to be adsorbed on C-surfaces; and the gaseous Al2O is active in the presence of C and AlCl3 (or AlCl2). Besides, AlCl2 vapor in the condensation zone could be dispropor tionated into gaseous AlCl. ©, 2015, Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology. All right reserved.


Kong X.,National Engineering Laboratory for Vacuum Metallurgy | Kong X.,Central South University | Kong X.,State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization | Xiong H.,National Engineering Laboratory for Vacuum Metallurgy | And 15 more authors.
Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology | Year: 2014

Removal of arsenic from high-arsenic crude lead by vacuum distillation was modeled, theoretically calculated, and experimentally evaluated. The effects of the distillationconditions, including the pressure, distillation temperature and time, on the removal rate of arsenic and direct recovery of lead were examined. The calculated results show that vacuum distillation is feasible to effectively remove arsenic from crude lead with high arsenic impurity at a moderate temperature because at a given elevated temperature, the saturated vapor pressure of arsenic is much higher than that of lead, and because arsenic and lead cannot form an intermetallic compound. The vacuum distillation was experimentally tested. Distilled at a pressure of 5 to 15 Pa and at 973 K for 30 min, the removal rate of arsenic and direct recovery rate of lead were found to be 80% and 97%, respectively. Besides, copper impurity was found to negatively affect the removal of arsenic because copper and arsenic form an intermetallic compound. ©, 2014, Science Press. All right reserved.

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