| 摘要 |
PURPOSE:To enable electrostatic separation treatment under an air atmosphere while an explosion accident is certainly prevented, by charging stock fine powdery coal by corona discharge in electrostatic separation treatment. CONSTITUTION:After the average particle size of stock fine powdery coal is adjusted to a desired range by using a dry mill, said fine powdery coal is transported by an air stream with ambient temp. and humidity to be charged in a dry electric separator 2 along with transport air in such a state that the concn. of coal in air is adjusted and held to 150-70g/m<2>. In such a state that the air passing speed in the electric separator 2 is adjusted and held to 0.2m/s or more, predetermined voltage of 20-35kV is applied between a discharge electrode and an earth electrode set at an interval of 200mm and the charged stock fine powdery coal is subjected to electrostatic separation treatment under a corona discharge state. By this treatment method, the generation of spark discharge causing explosion can be avoided and non-oxidative gas becomes unnecessary.
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