WET SPECIFIC GRAVITY SEPARATION METHOD FOR PLASTIC WASTE

摘要

PROBLEM TO BE SOLVED: To recover polystyrene which cannot be recovered with water as a specific gravity liquid by using a specific gravity liquid with the addition of a specific gravity falling within a specific range such as carbonic acid or ammonium derivative, especially, urea when wet separating by specific gravity a harmful plastic waste containing chlorine for combustion or blowing in a blast furnace. SOLUTION: Plastic waste loaded into a hopper 1a is loaded into a crusher 2 by a conveyor 1. The plastic waste crushed to the appropriate size (5-50mm) by the crusher 2 is loaded into a mixing tank 5 through a blower 3 and a cyclone 4, and the crushings are mixed and dispersed into a specific gravity liquid whose specific gravity is set at 11-13 with the addition of carbonic acid of ammonium derivative especially urea. The specific gravity liquid mixed with the crushings is sent to a supply aperture 9 in a specific gravity separation tank 8 with the help of a pump 7 and is separated to the upper part and the lower part of the interior of the specific gravity separation tank 8 is accordance with a specific gravity difference from the specific gravity liquid. Thus it is possible to recover plastics such as polystyrene from the internal upper part of the specific gravity separation tank 8 with the assistance of the specific gravity liquid.