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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 in Yunnan Province | Jiang W.,Kunming University of Science and Technology | And 18 more authors.
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2016

The possibility of the separation of Pb-Sb alloys by vacuum distillation was investigated theoretically. The results show that Pb and Sb can be separated by vacuum distillation. However, the experimental results show that vacuum distillation technique does not provide clear separation. According to the literature, Pb-Sb alloys belong to azeotropic compounds under some certain temperature; the experiment and computer simulation were carried out based on the exceptional condition so as to analyze the reason from the experiment and microstructure of Pb-Sb alloys perspective. The separation of Pb-Sb alloys by vacuum distillation was experimentally carried out to probe the azeotropic point. Also, the functions, such as partial radial distributions functions, the structure factor, mean square displacement, and the density of state, were calculated by ab-initio molecular dynamics for the representation of the structure and properties of Pb-Sb alloys with different composition of Sb. The experimental results indicate that there exists common volatilization for Pb-Sb alloys when Sb content is 16.5 wt pct. On the other hand, the calculation results show that there is an intense interaction between Pb and Sb when Sb content is 22 wt pct, which supports the experimental results although Sb content is slightly deviation. © 2016 The Minerals, Metals & Materials Society and ASM International


Kong L.,Kunming University of Science and Technology | Kong L.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Yang B.,Kunming University of Science and Technology | Yang B.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | And 4 more authors.
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2014

Based on the molecular interaction volume model (MIVM), the activities of components of Sn-Sb, Sb-Bi, Sn-Zn, Sn-Cu, and Sn-Ag alloys were predicted. The predicted values are in good agreement with the experimental data, which indicate that the MIVM is of better stability and reliability due to its good physical basis. A significant advantage of the MIVM lies in its ability to predict the thermodynamic properties of liquid alloys using only two parameters. The phase equilibria of Sn-Sb and Sn-Bi alloys were calculated based on the properties of pure components and the activity coefficients, which indicates that Sn-Sb and Sn-Bi alloys can be separated thoroughly by vacuum distillation. This study extends previous investigations and provides an effective and convenient model on which to base refining simulations for Sn-based alloys. © 2014 The Minerals, Metals & Materials Society and ASM International.


Wang F.,Kunming University of Science and Technology | Yang B.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Yang B.,State Key Laboratory Breed Base Of Complex Nonfer Met Rsrc Clear Utiliz In Yunnan Prov | Liu D.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | And 7 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

As a novel red long afterglow phosphor, Si4+ and Ti4+ ion codoped Gd2O2S:Eu phosphor with spherical morphology, sub-micrometer size and narrow particle size distribution was synthesized by solid-state reaction in vacuum. The vacuum synthesis mechanism was determined by thermal analysis. The crystal structure, luminescence properties and mechanisms were investigated respectively by XRD, SEM and fluorescence spectrophotometer. The results show that well-crystallized Gd2O2S:Eu,Si,Ti phosphors are of hexagonal structure which is in agreement with the standard powder peak positions of Gd2O2S hexagonal phase. It displays pure red emission because of the strongest peaks at 627 nm and 617 nm which are attributed to energy transfer (5D0- 7F2). There is a little blue shift of charge transfer excitation band in the excitation spectra between the bulk and sub-micrometer-sized samples, which may stem from size dependent shift and different lattice distortion in the position of the Eu3+-ligand electron transfer absorption/excitation band. To further study the influence of the impurities in Gd2O2S:Eu crystals on crystal growth, the simulated crystal face and its XRD patterns were illustrated. The preferred orientation of crystal growth changed from crystal face (1 0 1) to (1 0 0) thus to result in different luminescence mechanisms.


Li L.,Kunming University of Science and Technology | Li L.,State Key Laboratory Breeding Base of Complex Non ferrous Metal Resources Clear Utilization | Li L.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Tian Y.,Kunming University of Science and Technology | And 11 more authors.
Journal of Central South University | Year: 2013

The feasibility of separation of lead anode slime with low silver by vacuum distillation was analyzed theoretically. The volatilization rates and mass fractions of elements, influenced by distillation temperature, heat preservation time and material thickness, were investigated under laboratory conditions. The experimental results indicate that almost all of lead and bismuth can be separated from silver-contained multicomponent alloy at 1 223 K for 45 min when the chamber pressure maintains at 10-25 Pa. Silver can be easily enriched in the residue and its mass fraction increases from 3.6% to 27.8% when the distillation temperature is between 1 133 K and 1 373 K. Due to the forming of intermetallic compounds Cu2Sb, Cu10Sb3 and Ag3Sb, the antimony could not be evaporated completely during the vacuum distillation. EDS analysis indicates that the condensate has a columnar crystal structure. © 2013 Central South University Press and Springer-Verlag Berlin Heidelberg.


Wang F.,Kunming University of Science and Technology | Wang F.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Wang F.,State Key Laboratory Breed Base Of Complex Nonfer Metal Resources Clear Utilization In Yunnan Province | Chen X.,Kunming University of Science and Technology | And 11 more authors.
Journal of Molecular Structure | Year: 2012

Quantum chemistry and experimental method were used to study on pure and doped Gd2O2S crystals in this paper. The band structure and DOS diagrams of pure and doped Gd2O2S crystals which calculated by using DFT (Density Functional Theory) method were illustrated to explain the luminescent properties of impurities in crystals. The calculations of the crystal structure were finished by using the program of CASTEP (Cambridge Sequential Total Energy Package). The samples showed the characteristic emissions of Tb3+ ions with 5D4- 7FJ transitions and Eu3+ ions with 5D0-7FJ transitions which emit pure green luminescence and red luminescence respectively. The experimental excitation spectra of Tb3+ and Eu3+ doped Gd 2O2S are in agreement of the DOS diagrams over the explored energy range, which has allowed a better understanding of different luminescence mechanisms of Tb3+ and Eu3+ in Gd 2O2S crystals. © 2012 Elsevier B.V. All rights reserved.


Kong L.-X.,Kunming University of Science and Technology | Kong L.-X.,State Key Laboratory Breed Base Of Complex Nonfer Metal Resources Clear Utilization In Yunnan Province | Kong L.-X.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Yang B.,Kunming University of Science and Technology | And 12 more authors.
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2013

Based on the molecular interaction volume model (MIVM), the activities of components of Pb-Sn-Sb ternary alloy were predicted. The vapor-liquid phase equilibrium of Pb-Sn-Sb alloy system was calculated using the activity coefficients of Pb-Sn-Sb alloy system in the process of vacuum distillation. The calculated results show that the content of Sn in vapor phase increases with the increasing distillation temperature and content of Sn in liquid phase. However, the content of Sn in vapor phase is only 0.45% (mass fraction) while 97% in liquid phase at 1100 C, which shows that the separating effect is very well. Experimental investigations on the separation of Pb-Sn-Sb ternary alloy were carried out in the distillation temperature range of 1100-1300 C under vacuum condition. It is found that the Sn content in vapor phase is 0.54% while 97% in liquid phase at 1100 C. Finally, the predicted data were compared with the experimental results showing good agreement with each other. © 2013 The Nonferrous Metals Society of China.


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.


Kong L.,Kunming University of Science and Technology | Kong L.,State Key Laboratory Breed Base Of Complex Nonfer Metal Resources Clear Utilization In Yunnan Province | Kong L.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Yang B.,Kunming University of Science and Technology | And 11 more authors.
Vacuum | Year: 2014

In this paper, the molecular interaction volume model (MIVM) has been used for a calculation of the activities of components of Pb-Sn-Sb ternary alloy system. The separation coefficients of the related binary alloys Sn-Pb and Sn-Sb and the vapor-liquid phase equilibrium of the Pb-Sn-Sb alloy system were also calculated by using the MIVM. Experiments for the separation of the Pb-Sn-Sb ternary alloy were carried out for the proper interpretation of the results of the model. The predicted data are in good agreement with the experimental results, which indicates that MIVM is reliable and convenient since it has certain physical meaning from the viewpoint of statistical thermodynamics and requires only two infinite dilute activity coefficients for each sub-binary system. © 2013 Elsevier Ltd. All rights reserved.


Yang C.-B.,Kunming University of Science and Technology | Yang C.-B.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Yang C.-B.,State Key Laboratory Breed Base Of Complex Nonfer Metal Resources Clear Utilization In Yunnan Province | Tian Y.,Kunming University of Science and Technology | And 14 more authors.
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2014

Recent findings related to coagulable magnesium vapor nucleation and growth in vacuum were assessed critically, with emphasis on understanding these processes at a fundamental molecular level. The effects of magnesium vapor pressure, condensation temperature, and condensation zone temperature gradient on magnesium vapor nucleation in phase transitions and condensation from atomic collision and coacervation with collision under vacuum conditions were discussed. Magnesium powder and magnesium lump condensates were produced under different conditions and characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The right condensation zone temperature approach to the liquid transition primarily improved the magnesium vapor concentration rate. The gas-solid phase transition was primarily inhibited by setting a small condenser temperature gradient. Under the right condensation temperature and temperature gradients, increasing magnesium vapor partial pressure improved crystallization and reduced the oxidation rate. © 2014 The Nonferrous Metals Society of China.


Wang F.,Kunming University of Science and Technology | Wang F.,Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province | Wang F.,State Key Laboratory Breed Base Of Complex Nonferrous Metal Rsrc Clear Utilization In Yunnan Province | Liu D.,Kunming University of Science and Technology | And 8 more authors.
TMS Annual Meeting | Year: 2013

Gd2O2S:Tb phosphors were synthesized by vacuum method under different firing schedules. Compared to traditional high temperature solid state reaction, the synthesis temperature was reduced considerably. The optimized synthesis temperature was 725°C. By the analysis of X-ray diffractions(XRD), scanning electronic microscopy (SEM), transmission electron microscopy(TEM) and fluorescence spectroscopy, it can be confirmed that no new phase was introduced and the particle size was dramatically diminished to only tens of nanometers. The energy transfer around 272nm of Gd2O 2S:Tb nanophosphors were observed with high intensity in the excitaion spectrum, which may cause the spin forbidden radiative transition to spin-allowed transition. 5D4 - 7FJ transitions of Tb3+ ion were mainly concentrated in the narrow green emissive spectrum(535 ∼ 555nm) with its sharp peak at 545nm. With respect to bulk phosphor, the observed red shift was determined in the emission spectra of Gd2O2S:Tb nanophosphor so as to enhance the chroma purity.

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