Comparative on causes and accumulation of selenium in the tree-rings ambient high-selenium coal combustion area from Yutangba；Hubei；China

IEECAS SKLLQG

Health effects of arsenic；fluorine；and selenium from indoor burning of Chinese coal

IEECAS SKLLQG

Distribution and mode of occurrence of As；Hg and Se and sulfur in coal Seam 3 of the Shanxi Formation,Yanzhou Coalfield；China

IEECAS SKLLQG

Factors that influence the extraction of polycyclic aromatic hydrocarbons from coal

IEECAS SKLLQG

Mineral and chemical composition and some trace element contents in coals and coal ashes from Huaibei coal field, China

IEECAS SKLLQG

The characterization of coal quality from the Jining coalfield

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A novel form of carbon micro-balls from coal

A novel form of ball-like carbon material with its size in micrometer range was prepared from coal with nickel as catalyst by arc plasma method. The carbon material has been systematically studied by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and ultraviolet laser Raman spectroscopy. The SEM observation shows that the novel carbon material exists in various forms such as individual balls, net-like and plate-like forms, all of which have a quite smooth surface. The diameters of these carbon spheres are quite uniform and in a narrow range of 10-20 mum. The EDS analysis reveals that the ball-like carbon material contains more than 99.5% of carbon and a little amount of other elements such as nickel, silicon and aluminum, The XRD and UV-Raman results reveal that the novel carbon material is a kind of highly graphitized carbon. The growth mechanism of the ball-like carbon material was proposed and discussed in terms of arc plasma parameters and the chemical structure of coal-based carbon. (C) 2002 Elsevier Science Ltd. All rights reserved.