Method and facility for sorting and separating waste plastic

Abstract

Disclosed is a facility for precisely sorting, by material, waste plastic that includes many types of material. Said facility is provided with: a crusher (11) that pulverizes a waste plastic feedstock into waste plastic fragments having a prescribed size; a steam-cleaning device (13) that is disposed downstream from the crusher and that cleans the waste plastic fragments; a primary wet specific-gravity sorter (14) and a secondary wet specific-gravity sorter (15) that are disposed downstream from the steam-cleaning device and that use separation liquids, which have specific gravities in the middle of the specific gravities of the materials included in the waste plastic fragments, to separate out at most three types of floating or sinking specific-gravity-sorted fragments; and first through third electrostatic separation devices (16A-16C), each of which is disposed downstream of the primary and secondary wet specific-gravity sorters and has a frictional charging device, which frictionally charges the specific-gravity-sorted fragments, and an electrostatic sorter that puts the frictionally-charged specific-gravity-sorted fragments in an electrostatic field between a rotating drum electrode to which a high voltage is applied and an opposing electrode, thereby changing the direction the fragments fall and separating said fragments by material.

Description

technical field [0001] The invention relates to a sorting and separating method and sorting and separating equipment for waste plastics, which are used to sort waste plastics containing various materials, such as waste household appliances and waste automobiles, according to their materials. Background technique [0002] In recent years, Japan has carried out a large amount of recycling and reuse of waste plastics based on the home appliance recycling law. In order to reuse waste plastics, it is necessary to sort and recycle with high precision according to the material in the fields of waste home appliances and waste cars. [0003] For example, as shown in Patent Document 1, the inventors of the present invention have developed the following electrostatic separation method, which triboelectrically charges plastic sheets by putting these plastic sheets into the electrostatic field formed between the positive counter electrode and the negative drum electrode. In this method,...

AI Technical Summary

Problems solved by technology

At this time, waste plastic pieces containing various materials are separated on the electrostatic separator on the most upstream side. If the separation accuracy here is low, it is difficult to improve the separation accuracy of the electrostatic separator on the downstream side, that is, it is difficult High-precision sorting and separation of waste plastic sheets containing various materials by type by using electrostatic separation method

Images