Density-based separation of thermoplastics found in the post-consumer waste stream

✍ Scribed by Michael S. Super; Robert M. Enick; Eric J. Beckman

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 728 KB
• Volume: 9
• Category: Article
• ISSN: 0921-3449
• DOI: 10.1016/0921-3449(93)90034-d

✦ Synopsis

Separation of thermoplastics from each other and from contaminants facilitates their recycling and improves the properties of the reprocessed material. Clean, dry, shredded thermoplastics obtained from post-consumer, plastic waste were separated using pure CO2 and mixtures of CO2 and SF 6 in a lab-scale, density-based separator. The separator was designed to operate at the pressures and temperatures required to attain the appropriate densities for the separations using these near-critical fluids. Separation efficiency, factors affecting separation purity, and favorable operating conditions and procedures were determined. Several thermoplastic mixtures were separated, including HDPE/LDPE/ PP and PVC/PET. The purity of the separated homopolymers ranged from 100%-77% by weight, with most runs yielding 96%-100% purity.