The reduction of ilmenite concentrate by hydrogen gas was investigated in the temperature range of 500 to 1200℃. The microstructure and phase transition of the reduction products were studied by X-ray diffraction (...The reduction of ilmenite concentrate by hydrogen gas was investigated in the temperature range of 500 to 1200℃. The microstructure and phase transition of the reduction products were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical microscopy (OM). It was found that the weight loss and iron metallization rate increased with the increase of reduction temperature and reaction time. The iron metallization rate could reach 87.5% when the sample was reduced at 1150℃ for 80 min. The final phase constituents mainly consist of Fe, M305 solid solution phase (M=Mg, Ti, and Fe), and few titanium oxide. Microstructure analysis shows that the surfaces of the reduction products have many holes and cracks and the reactions take place from the exterior of the grain to its interior. The kinetics of reduction indicates that the rate-controlling step is diffusion process control with the activation energy of 89 kJ.mo1-1.展开更多
The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results ...The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results of our preliminary experiments. During the process,various process parameters were studied,including the roasting temperature,the addition of NH_4 Cl,the roasting time,the leaching time,and the liquid-to-solid ratio. The roasted products and leach residues were characterized by X-ray diffraction and vibrational spectroscopy. Under the optimum condition,95% of Ni,98% of Cu,and 88% of Co were recovered. In addition,the removal of iron was studied in the water leaching stage. The results demonstrate that this process provides an effective approach for extracting multiple metals from complex concentrates or ores.展开更多
In order to recover valuable rare earth elements from Nd-Fe-B permanent magnet scraps, a high-temperature pyrometallurgical process was developed in this work. The magnet scraps were first pulverized and oxidized at 1...In order to recover valuable rare earth elements from Nd-Fe-B permanent magnet scraps, a high-temperature pyrometallurgical process was developed in this work. The magnet scraps were first pulverized and oxidized at 1000℃ in normal atmosphere. The oxidized mixtures were then selectively reduced by carbon in the temperature range of 1400-1550℃. In this way, the rare earth elements were extracted to the form of oxides, whereas Fe and B were separated to metal phase. For improving the purity of rare earth oxides, the effects of temperature and reaction time on the reduction of B_(2)O_(3) in oxide phase were investigated. It is found that increasing reaction temperature and extending reaction time will help the reduction of B_(2)O_(3) contents in rare earth oxide phase. Almost all rare earth elements can be enriched in the oxide phase with the highest purity of 95 %.展开更多
The study of controlled rolling/controlled cooling process parameters which affect the microstructure and mechanical properties of a novel pipeline steel has been optimized by the orthogonal experiment with four facto...The study of controlled rolling/controlled cooling process parameters which affect the microstructure and mechanical properties of a novel pipeline steel has been optimized by the orthogonal experiment with four factors and three levels in this paper. However, the parameters of thermo-mechanical control process (TMCP) optimized by the Gleeble-3500 hot simulator could not satisfy performance requirements of the X100 pipeline steel. In order to improve the performance of this steel, the influence of finish cooling temperature (FCT) on the microstructure and property is studied in detail. It is found that, as this steel is thermo-mechanically treated by this set of parameters (the start heating temperature, finish rolling temperature (FRT), FCT and cooling rate of 1,180 ℃, 810 ℃, 350 ℃ and 35 ℃/s, respectively), the micro- structures are mainly composed of granular bainite (GB) and acicular ferrite (AF). The effective grain sizes are below 20 μm; the steel reaches the optimal balance between the strength and the toughness; the yield strength is 695 MPa; the tensile strength is 768 MPa; the elongation is 16.6 %; the impact energy is 262 J at room temperature. All indexes could meet the requirements of X100 pipeline steel.展开更多
In this paper, the thermodynamics of the reduction of ilmenite using multiple gases (H<sub>2</sub>/CO) was calculated. It is found that the metallization rate of 20.1%–98.8%, H<sub>2</sub> con...In this paper, the thermodynamics of the reduction of ilmenite using multiple gases (H<sub>2</sub>/CO) was calculated. It is found that the metallization rate of 20.1%–98.8%, H<sub>2</sub> consumption rate of 43.0%–99.1%, and carbon deposition amount of 5.7×10<sup>?7</sup>?0.49mol can be obtained based on the conditions of hydrogen volume fraction of 10%–90% and temperature of 450–1200°C. Experimental study was also carried out using synthetic ilmenite as initial materials and reduced in a static bed reactor at 1100°C. The metallization rate reaches 97% when the multiple gas (70% H<sub>2</sub>/10% CO/20% Ar) flow rate is 120ml·min<sup>?1</sup>. A thermogravimetric analyzer was used to measure the variation of sample weight caused by the deposition of solid carbon. The amount of carbon deposited during experiments reaches its maximum while the original hydrogen volume content is 20%. The experimental results are well consistent with the thermodynamic analysis.展开更多
In this study, the Al-Fe-Mn ternary system is reassessed by the CALPHAD method. Three new ternary intermetallic compounds are initially described and a rea- sonable and self-consistent set of thermodynamic parameters ...In this study, the Al-Fe-Mn ternary system is reassessed by the CALPHAD method. Three new ternary intermetallic compounds are initially described and a rea- sonable and self-consistent set of thermodynamic parameters are established to describe this system. The 973 K, 1 073K, 1 173K, 1 273K, 1 373K, and 1 473K isothermal sections and the 1 073 K, 1 013 K, 968 K and 913 K isothermal sections at the AI corner as well as the liquidus projection at the Al corner are calculated. It is shown that the calculated results are in good agreement with almost all of the experimental results previously reported.展开更多
The permeability and stability of Sm_(0.7)Sr_(0.3)CoO_(3-δ)(SSCO) regarding the special requirements for carbon capture and storage(CCS) application were investigated.Pure CO_ was used as the sweep gas at 9...The permeability and stability of Sm_(0.7)Sr_(0.3)CoO_(3-δ)(SSCO) regarding the special requirements for carbon capture and storage(CCS) application were investigated.Pure CO_ was used as the sweep gas at 900 °C,leading to that the oxygen permeation flux decreases by about 34 %.Several cycles of changing the sweep gas between helium and CO_2 indicate the good reversibility of this degradation.Both carbonate formation and adsorption of CO_2 on the membrane surface are responsible for the degradation of the membrane performance.The better CO_2 resistance results from the substitution of Sm for Sr due to the higher acidity of Sm_2O_3(1.278) than that of Sr O(0.978) and a discontinuous layer of carbonate.展开更多
基金Project(2014CB643403)supported by the National Basic Research Program of ChinaProjects(51225401,51304132,51574164)supported by the National Natural Science Foundation of China+1 种基金Project(14JC1491400)supported by the Science and Technology Commissions of Shanghai Municipality,ChinaProject(2013GZ0146)supported by the Sichuan Province,China
基金Project(51574164)supported by the National Natural Science Foundation of ChinaProject(2014CB643403)supported by the National Basic Research Program of China
基金supported by the Postgraduate Innovative Foundation of Shanghai University (SHUCX091031)the National Natural Science Foundation of China (No.51074105)the National Basic Research Priorities Program of China (No.2007CB613606)
文摘The reduction of ilmenite concentrate by hydrogen gas was investigated in the temperature range of 500 to 1200℃. The microstructure and phase transition of the reduction products were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical microscopy (OM). It was found that the weight loss and iron metallization rate increased with the increase of reduction temperature and reaction time. The iron metallization rate could reach 87.5% when the sample was reduced at 1150℃ for 80 min. The final phase constituents mainly consist of Fe, M305 solid solution phase (M=Mg, Ti, and Fe), and few titanium oxide. Microstructure analysis shows that the surfaces of the reduction products have many holes and cracks and the reactions take place from the exterior of the grain to its interior. The kinetics of reduction indicates that the rate-controlling step is diffusion process control with the activation energy of 89 kJ.mo1-1.
基金financially supported by the National Key Basic Research Program of China(No.2014CB643403)the National Science Fund for Distinguished Young Scholars(No.51225401)
文摘The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results of our preliminary experiments. During the process,various process parameters were studied,including the roasting temperature,the addition of NH_4 Cl,the roasting time,the leaching time,and the liquid-to-solid ratio. The roasted products and leach residues were characterized by X-ray diffraction and vibrational spectroscopy. Under the optimum condition,95% of Ni,98% of Cu,and 88% of Co were recovered. In addition,the removal of iron was studied in the water leaching stage. The results demonstrate that this process provides an effective approach for extracting multiple metals from complex concentrates or ores.
基金the National Key Basic Research Program of China(No.2012CB722805)。
文摘In order to recover valuable rare earth elements from Nd-Fe-B permanent magnet scraps, a high-temperature pyrometallurgical process was developed in this work. The magnet scraps were first pulverized and oxidized at 1000℃ in normal atmosphere. The oxidized mixtures were then selectively reduced by carbon in the temperature range of 1400-1550℃. In this way, the rare earth elements were extracted to the form of oxides, whereas Fe and B were separated to metal phase. For improving the purity of rare earth oxides, the effects of temperature and reaction time on the reduction of B_(2)O_(3) in oxide phase were investigated. It is found that increasing reaction temperature and extending reaction time will help the reduction of B_(2)O_(3) contents in rare earth oxide phase. Almost all rare earth elements can be enriched in the oxide phase with the highest purity of 95 %.
基金the National Nature Science Foundation of China(Grant Nos.51374142,51225401)the Science and Technology Fund of Scientific Committee of Shanghai(Grant Nos.11520500100,11DZ2283400)the Open Project of the State Key Laboratory of New Ferrous Metallurgy Technology(Grant No. KF12-05)
文摘The study of controlled rolling/controlled cooling process parameters which affect the microstructure and mechanical properties of a novel pipeline steel has been optimized by the orthogonal experiment with four factors and three levels in this paper. However, the parameters of thermo-mechanical control process (TMCP) optimized by the Gleeble-3500 hot simulator could not satisfy performance requirements of the X100 pipeline steel. In order to improve the performance of this steel, the influence of finish cooling temperature (FCT) on the microstructure and property is studied in detail. It is found that, as this steel is thermo-mechanically treated by this set of parameters (the start heating temperature, finish rolling temperature (FRT), FCT and cooling rate of 1,180 ℃, 810 ℃, 350 ℃ and 35 ℃/s, respectively), the micro- structures are mainly composed of granular bainite (GB) and acicular ferrite (AF). The effective grain sizes are below 20 μm; the steel reaches the optimal balance between the strength and the toughness; the yield strength is 695 MPa; the tensile strength is 768 MPa; the elongation is 16.6 %; the impact energy is 262 J at room temperature. All indexes could meet the requirements of X100 pipeline steel.
基金financially supported by the National Natural Science Foundation of China(No.51074105)China National Funds for Distinguished Young Scientists(No.51225401)
文摘In this paper, the thermodynamics of the reduction of ilmenite using multiple gases (H<sub>2</sub>/CO) was calculated. It is found that the metallization rate of 20.1%–98.8%, H<sub>2</sub> consumption rate of 43.0%–99.1%, and carbon deposition amount of 5.7×10<sup>?7</sup>?0.49mol can be obtained based on the conditions of hydrogen volume fraction of 10%–90% and temperature of 450–1200°C. Experimental study was also carried out using synthetic ilmenite as initial materials and reduced in a static bed reactor at 1100°C. The metallization rate reaches 97% when the multiple gas (70% H<sub>2</sub>/10% CO/20% Ar) flow rate is 120ml·min<sup>?1</sup>. A thermogravimetric analyzer was used to measure the variation of sample weight caused by the deposition of solid carbon. The amount of carbon deposited during experiments reaches its maximum while the original hydrogen volume content is 20%. The experimental results are well consistent with the thermodynamic analysis.
文摘In this study, the Al-Fe-Mn ternary system is reassessed by the CALPHAD method. Three new ternary intermetallic compounds are initially described and a rea- sonable and self-consistent set of thermodynamic parameters are established to describe this system. The 973 K, 1 073K, 1 173K, 1 273K, 1 373K, and 1 473K isothermal sections and the 1 073 K, 1 013 K, 968 K and 913 K isothermal sections at the AI corner as well as the liquidus projection at the Al corner are calculated. It is shown that the calculated results are in good agreement with almost all of the experimental results previously reported.
基金financially supported by the National Natural Science Foundation of China (Nos.51174133,51274139 and 51225401)the Science and Technology Commission of Shanghai Municipality (No.11ZR1412900)
文摘The permeability and stability of Sm_(0.7)Sr_(0.3)CoO_(3-δ)(SSCO) regarding the special requirements for carbon capture and storage(CCS) application were investigated.Pure CO_ was used as the sweep gas at 900 °C,leading to that the oxygen permeation flux decreases by about 34 %.Several cycles of changing the sweep gas between helium and CO_2 indicate the good reversibility of this degradation.Both carbonate formation and adsorption of CO_2 on the membrane surface are responsible for the degradation of the membrane performance.The better CO_2 resistance results from the substitution of Sm for Sr due to the higher acidity of Sm_2O_3(1.278) than that of Sr O(0.978) and a discontinuous layer of carbonate.