The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform

Chuan Liang - One of the best experts on this subject based on the ideXlab platform.

  • effect of natural weathering processes on size and density compositions of Bituminous Coal
    Energy & Fuels, 2014
    Co-Authors: Zelin Zhang, Chuan Liang, Xiaodong Ge
    Abstract:

    It is well-known that natural weathering processes can change the surface properties of Coal. The carbon content on the Coal surface can be reduced, while the oxygen content can be increased, by natural weathering processes. However, there is little direct and deep research into the effect of natural weathering processes on the size and density compositions of Coal. In this investigation, the changes in the size and density compositions of Bituminous Coal before and after natural weathering processes were discussed. X-ray photoelectron spectroscopy and scanning electron microscopy measurements were used to explain these changes in micro aspects. Throughout this paper, both the size and density compositions of Bituminous Coal could be affected by natural weathering processes. Natural weathering processes not only reduce the Coal particle size but also increase the Coal particle density.

  • Investigation of changes in surface properties of Bituminous Coal during natural weathering processes by XPS and SEM
    Applied Surface Science, 2014
    Co-Authors: Wencheng Xia, Jianguo Yang, Chuan Liang
    Abstract:

    In this investigation, XPS and SEM were used to indicate the changes in surface properties of Bituminous Coal during natural weathering processes. Natural weathering processes of Bituminous Coal were conducted on the roof. XPS results showed that the content of CC and CH groups on Bituminous Coal surface decreased but the content of CO, CO, and OCO groups increased after natural weathering processes. Meanwhile, the contents of Al and Si elements on Bituminous Coal surface were also increased. SEM results showed that the surface roughness of Bituminous Coal was increased after natural weathering processes. Natural weathering processes not only changed surface chemical composition of Bituminous Coal but also changed surface topography of Bituminous Coal. In addition, natural weathering processes made Bituminous Coal surface more hydrophilic.

Xiaodong Ge - One of the best experts on this subject based on the ideXlab platform.

  • effect of natural weathering processes on size and density compositions of Bituminous Coal
    Energy & Fuels, 2014
    Co-Authors: Zelin Zhang, Chuan Liang, Xiaodong Ge
    Abstract:

    It is well-known that natural weathering processes can change the surface properties of Coal. The carbon content on the Coal surface can be reduced, while the oxygen content can be increased, by natural weathering processes. However, there is little direct and deep research into the effect of natural weathering processes on the size and density compositions of Coal. In this investigation, the changes in the size and density compositions of Bituminous Coal before and after natural weathering processes were discussed. X-ray photoelectron spectroscopy and scanning electron microscopy measurements were used to explain these changes in micro aspects. Throughout this paper, both the size and density compositions of Bituminous Coal could be affected by natural weathering processes. Natural weathering processes not only reduce the Coal particle size but also increase the Coal particle density.

Wencheng Xia - One of the best experts on this subject based on the ideXlab platform.

  • Effect of middle-temperature pyrolysis on the surface hydrophobicity of sub-Bituminous Coal
    Energy Sources Part A: Recovery Utilization and Environmental Effects, 2017
    Co-Authors: Wencheng Xia, Chenkai Niu
    Abstract:

    Middle-temperature pyrolysis is widely used to convert sub-Bituminous Coal into gas/liquid products and the Coal char, which benefits the utilization of low rank Coal resources. However, the Coal c...

  • Effect of low-temperature pyrolysis on surface properties of sub-Bituminous Coal sample and its relationship to flotation response
    Fuel, 2017
    Co-Authors: Niu Chenkai, Wencheng Xia, Guangyuan Xie
    Abstract:

    Coal spontaneous combustion makes Coal suffer a high-temperature heating process (similar to a low-temperature pyrolysis). Additionally, low rank Coal is considered to be friendly utilized through two steps, i.e. low-temperature pyrolysis of low rank Coal to gain gas/liquid components and then Coal char forwarded to the burning or other chemical applications. Therefore, it is necessary to investigate the effect of low-temperature pyrolysis on the surface properties of low rank Coal and its role in the floatability of Coal particles because Coal already suffering spontaneous combustion should be upgraded before usage. In this investigation, SEM, XPS, attachment time and flotation tests were employed to reveal the changes of surface properties and floatability of sub-Bituminous Coal before and after the pyrolysis. After the pyrolysis, a significant mass loss was observed and many pores/cracks were newly created as well as the content of hydrophobic functional groups on Coal surface was increased whereas the content of hydrophilic oxygen-containing functional groups was reduced. The attachment time of Coal-bubble was significantly decreased after the pyrolysis, which directly made an increase in the hydrophobicity and floatability of sub-Bituminous Coal. The findings of this paper may be useful for a better use of sub-Bituminous Coal resources because sub-Bituminous Coal is well known as difficult to float and sub-Bituminous Coal fines are usually wasted in Coal preparation plants. This paper proposes that Coal char from sub-Bituminous Coal may be forwarded to a further upgrading process (i.e. flotation) because the floatability of sub-Bituminous Coal is significantly improved by the pyrolysis.

  • Investigation of changes in surface properties of Bituminous Coal during natural weathering processes by XPS and SEM
    Applied Surface Science, 2014
    Co-Authors: Wencheng Xia, Jianguo Yang, Chuan Liang
    Abstract:

    In this investigation, XPS and SEM were used to indicate the changes in surface properties of Bituminous Coal during natural weathering processes. Natural weathering processes of Bituminous Coal were conducted on the roof. XPS results showed that the content of CC and CH groups on Bituminous Coal surface decreased but the content of CO, CO, and OCO groups increased after natural weathering processes. Meanwhile, the contents of Al and Si elements on Bituminous Coal surface were also increased. SEM results showed that the surface roughness of Bituminous Coal was increased after natural weathering processes. Natural weathering processes not only changed surface chemical composition of Bituminous Coal but also changed surface topography of Bituminous Coal. In addition, natural weathering processes made Bituminous Coal surface more hydrophilic.

Jianguo Yang - One of the best experts on this subject based on the ideXlab platform.

  • Surface hydrophobicity of sub-Bituminous and meta-Bituminous Coal and their flotation kinetics
    Fuel, 2019
    Co-Authors: You Zhou, Boris Albijanic, Bogale Tadesse, Yuling Wang, Jianguo Yang, Xiangnan Zhu
    Abstract:

    Abstract This paper discusses the relationships between the surface properties of the sub-Bituminous and meta-Bituminous Coal and their flotation properties. Additionally, it was investigated whether the flotation kinetic constants, obtained using various flotation kinetic models, can be used for prediction of the flotation response. Both Coal samples had the very similar amount and type of impurities as confirmed by XRD. FTIR, contact angle, zeta potential and SEM measurements were used to study the Coal surface properties. It was found that the meta-Bituminous Coal was significantly more hydrophobic than the sub-Bituminous Coal and the Coal surface roughness was significantly more pronounced in the case of the sub-Bituminous Coal than that in the case of the meta-Bituminous Coal. For these reasons, the recovery of the meta-Bituminous Coal by flotation was dramatically higher than that of the sub-Bituminous Coal even in the presence of collector. Six flotation kinetic models successfully predicted the flotation data. Nevertheless, the modified first-order model was the only model that can be used to explain the flotation responses under a wide range of the experimental conditions. The reason is that for most flotation kinetic models, used in this study, particularly in the case of the sub-Bituminous Coal, the flotation rate constants decreased with increasing in collector dosage while the opposite is true in the case of the flotation recoveries.

  • Investigation of changes in surface properties of Bituminous Coal during natural weathering processes by XPS and SEM
    Applied Surface Science, 2014
    Co-Authors: Wencheng Xia, Jianguo Yang, Chuan Liang
    Abstract:

    In this investigation, XPS and SEM were used to indicate the changes in surface properties of Bituminous Coal during natural weathering processes. Natural weathering processes of Bituminous Coal were conducted on the roof. XPS results showed that the content of CC and CH groups on Bituminous Coal surface decreased but the content of CO, CO, and OCO groups increased after natural weathering processes. Meanwhile, the contents of Al and Si elements on Bituminous Coal surface were also increased. SEM results showed that the surface roughness of Bituminous Coal was increased after natural weathering processes. Natural weathering processes not only changed surface chemical composition of Bituminous Coal but also changed surface topography of Bituminous Coal. In addition, natural weathering processes made Bituminous Coal surface more hydrophilic.

Zelin Zhang - One of the best experts on this subject based on the ideXlab platform.

  • effect of natural weathering processes on size and density compositions of Bituminous Coal
    Energy & Fuels, 2014
    Co-Authors: Zelin Zhang, Chuan Liang, Xiaodong Ge
    Abstract:

    It is well-known that natural weathering processes can change the surface properties of Coal. The carbon content on the Coal surface can be reduced, while the oxygen content can be increased, by natural weathering processes. However, there is little direct and deep research into the effect of natural weathering processes on the size and density compositions of Coal. In this investigation, the changes in the size and density compositions of Bituminous Coal before and after natural weathering processes were discussed. X-ray photoelectron spectroscopy and scanning electron microscopy measurements were used to explain these changes in micro aspects. Throughout this paper, both the size and density compositions of Bituminous Coal could be affected by natural weathering processes. Natural weathering processes not only reduce the Coal particle size but also increase the Coal particle density.