PURPOSE: To change the crop ends of asphalt building materials to carbon particles having no tacky adhesiveness, to mix these carbon particles with asphalt raw materials so as to recycle the crop ends by heating the crop ends to a specific tap. while blowing incombustible gases in a vacuum furnace, then taking the coarse carbonized granular material out of this vacuum furnace.

CONSTITUTION: The crop ends 1 consisting of polyester nonwoven fabrics 7 generated according to installation of the asphalt building materials are first housed in the vacuum furnace 2. Next, gaseous nitrogen 5 is introduced into the vacuum furnace 2 and the crop ends 1 are heat treated at a specific tap. of 450°C under gaseous nitrogen flow. In succession, the crop ends 1 are taken out of the vacuum furnace 2 and are introduced into an agitating machine 3 where the crop ends are agitated with the carbon particles of particularly a grain size of 0.5 to 1m and thereafter, these particles are added and mixed to and with the asphalt raw materials in an asphalt raw material tank 4, by which the crop ends are recycled. On the other hand, the gases discharged from the vacuum furnace 2 are desulfurized in a desulfurizer 6 and are released outside the system. At this time, the carbon particles are completely carbonized and, therefore, lend themselves to carbon materials for electrodes, etc., as well.