METHOD OF MOLDING WASTE PLASTIC AND METHOD OF PYROLYZING WASTE PLASTIC

摘要

A waste plastic is molded to produce high-density granules. The granules are mixed with coal and the mixture is pyrolyzed in a coke oven to produce a high-strength coke. The waste plastic to be used as a raw material may be one comprising polyethylene, polypropylene, and polystyrene, which are plastics softening at a low temperature, in a total proportion of 50% or higher. This waste plastic is molded by a molding method in which the waste plastic is treated with a screw extruder and extruded from a nozzle. In the method, the waste plastic in the extruder is heated to a temperature of 180-260°C and gases in the extruder are sucked. By this operation, the polyethylene, polypropylene, and polystyrene are brought into a molten state and gases contained in the plastic are diminished. The plastic in this state is extruded from a nozzle having a diameter of 15-60 mm to thereby compression-mold it. Thereafter, the extrudate is cut and is cooled with a water cooler within three seconds after the cutting.