Ion-absorbed rare-earth ore is an important mineral resource which is widely extracted by in-situ leaching process. And such process generates a significant amount of impurities such as aluminum and iron ions in leach...Ion-absorbed rare-earth ore is an important mineral resource which is widely extracted by in-situ leaching process. And such process generates a significant amount of impurities such as aluminum and iron ions in leaching solution simultaneously. The surface characteristics and interactions by infrared spectroscopy and X-ray diffraction were studied to optimize the leaching conditions. It is found that the environment-friendly depressant LG-01 can react with the impurity ions through the formation of a new complex on the surface of leaching residues. Thus, it reduces significantly the concentration of impurity ions in leaching solution and improves the leaching rate of rare-earth ore. Moreover, a leaching rate of 95.6% and an impurity removal rate of 92% have been achieved under the optimized conditions.展开更多
A series of long afterglow phosphors, Eu2+, Dy3+, with different iron content were prepared by nano-coating process. The resulted precursors were characterized by Transmission Electron Microscope (TEM), which suggeste...A series of long afterglow phosphors, Eu2+, Dy3+, with different iron content were prepared by nano-coating process. The resulted precursors were characterized by Transmission Electron Microscope (TEM), which suggested that the precursor particles had nanometer size distribution. The optical quenching of iron impurity on the phosphor powders were investigated by X-Ray powder Diffraction (XRD) and photoluminescence methods. The XRD indicates that a pure monoclinic SrAl2O4∶Eu2+, Dy3+ was formed at 1200 ℃ and iron impurity up to 296.36×10-4% had no effect on the SrAl2O4∶Eu2+, Dy3+ phase structure. However, the luminescence intensity were strongly dependent on the trace iron impurity, which might be explained that iron displace the aluminium and form Fe-O bond, which competed energy with Eu2+ and transfer red them to infrared sites.展开更多
Carbon materials have been widely used as electrodes, but the mechanistic roles are still not clear due to the complexity of the carbon surface chemistry. Herein we clarify that intrinsic material properties of carbon...Carbon materials have been widely used as electrodes, but the mechanistic roles are still not clear due to the complexity of the carbon surface chemistry. Herein we clarify that intrinsic material properties of carbon have to be activated by extrinsic factors. Pure carbon has no catalytic activity when used as electrode for electrocatalytic water oxidation. The evolution of oxygen functional groups on the carbon surface with increasing potential and the subsequent formation of real active sites with iron impurities from the electrolyte have been confirmed. These in-situ formed active sites protect the carbon from deep oxidation. This unprecedented finding not only provides insight into the dynamic evolution of carbon electrode surface chemistry and raises awareness of the need for detailed surface analysis under operando conditions, but also suggests a direction for the development of scalable and high-performance carbonbased electrode systems for various electrochemical applications.展开更多
基金Project(51164010)supported by the National Natural Science Foundation of ChinaProject(2010GZC0048)supported by the Natural Science Foundation of Jiangxi Province,China
文摘Ion-absorbed rare-earth ore is an important mineral resource which is widely extracted by in-situ leaching process. And such process generates a significant amount of impurities such as aluminum and iron ions in leaching solution simultaneously. The surface characteristics and interactions by infrared spectroscopy and X-ray diffraction were studied to optimize the leaching conditions. It is found that the environment-friendly depressant LG-01 can react with the impurity ions through the formation of a new complex on the surface of leaching residues. Thus, it reduces significantly the concentration of impurity ions in leaching solution and improves the leaching rate of rare-earth ore. Moreover, a leaching rate of 95.6% and an impurity removal rate of 92% have been achieved under the optimized conditions.
基金the National Natural Science Foundation of China (20376009)
文摘A series of long afterglow phosphors, Eu2+, Dy3+, with different iron content were prepared by nano-coating process. The resulted precursors were characterized by Transmission Electron Microscope (TEM), which suggested that the precursor particles had nanometer size distribution. The optical quenching of iron impurity on the phosphor powders were investigated by X-Ray powder Diffraction (XRD) and photoluminescence methods. The XRD indicates that a pure monoclinic SrAl2O4∶Eu2+, Dy3+ was formed at 1200 ℃ and iron impurity up to 296.36×10-4% had no effect on the SrAl2O4∶Eu2+, Dy3+ phase structure. However, the luminescence intensity were strongly dependent on the trace iron impurity, which might be explained that iron displace the aluminium and form Fe-O bond, which competed energy with Eu2+ and transfer red them to infrared sites.
文摘Carbon materials have been widely used as electrodes, but the mechanistic roles are still not clear due to the complexity of the carbon surface chemistry. Herein we clarify that intrinsic material properties of carbon have to be activated by extrinsic factors. Pure carbon has no catalytic activity when used as electrode for electrocatalytic water oxidation. The evolution of oxygen functional groups on the carbon surface with increasing potential and the subsequent formation of real active sites with iron impurities from the electrolyte have been confirmed. These in-situ formed active sites protect the carbon from deep oxidation. This unprecedented finding not only provides insight into the dynamic evolution of carbon electrode surface chemistry and raises awareness of the need for detailed surface analysis under operando conditions, but also suggests a direction for the development of scalable and high-performance carbonbased electrode systems for various electrochemical applications.
