Recovery of plastic from municipal waste
US4160722A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 27, 1977 |
| Grant date | Jul 10, 1979 |
| Priority date | — |
| Expiry date | Jun 27, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/52
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The plastic discarded in municipal solid waste is recovered by a process wherein the waste is reduced to a particulate mass having a liquid content of 20% or more such that the paper and other absorbent constituents retain sufficient liquid to be substantially heavier than the sheet plastic pieces of comparable size. The mass is then subjected to an air separation treatment wherein the plastic pieces are blown free of the paper and other constituents of the mass. In one form, the solid waste is first pulped in water to slurry form, some of the fiber is recovered from the slurry by screening, and the reject flow from the screen is dewatered and subjected to the air separation treatment. In another form, the solid waste is dry shredded and the high specific gravity materials removed prior to pulping. In still another form, the dry material is wetted sufficiently for effective air separation of the plastic.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.