PURPOSE: To make it possible to transport burnt ashes to a treatment plant, preventing said ashes from flying off, by adding sintered earth to the burnt ashes containing harmful substances, stirring them, adding water thereto to knead them, and further adding particles to aid burning thereto, forming them into granules, and thereafter burning said granules to sinter their surfaces.

CONSTITUTION: Burnt ashes containing harmful substances such as hexavalent chrome or other heavy metals discharged from an electrostatic precipitator 1 or multicyclone 2 are sent to an ash hangar 3 and then said burnt ashes and bentonite from a bentonite hangar 4 are put into a kneader 6 to be mixed with each other, after which water is added thereto to knead said mixture, causing said mixture to take the form of clay, following which pulverized coal from a hangar 5 is added thereto so that the mixture is formed into granules covered with pulverized coal by rotation of the kneader 6. Said granules are transferred to a forming machine 7, where pulverized coal covering the granules is burnt by means of a gas burner 8 provided thereunder so as to sinter the surfaces of the granules. The burnt ashes having been treated in this manner are discharged from a discharge port 9 onto a conveyer 10 to be loaded on a transport vehicle, the ashes being prevented from scattering, and transported to a treatment plant, where the harmful substances thereof are treated.