PURPOSE: To improve the electrification efficiency of a triboelectrifying device by previously electrifying particles by radiation with UV beams before the particles are first impinged upon a wall for the purpose of executing the prescribed electrification.

CONSTITUTION: Particles are beforehand electrified in an irradiation chamber 10 by the radiation with a UV radiation device 1 and thereafter the prescribed electrification of the particles within a triboelectrifying device 2 is executed in the method for electrifying the particles within the triboelectrifying device 2, then separating the non-electrified particles. Consequently, the efficiency of the electrification in the triboelectrifying device may be enhanced. This method is suitable, for instance, for selective electrification of the component elements containing sulfur forming ash within pulverized powder.