Patents and other literature on recycling post-consumer plastics from various sources (e.g., municipal solid waste) indicate that unit operations common to minerals processing have been seriously considered at various times. A review of the available literature and statistics on recoverable plastics reveals that only 2.4 percent is recycled. This article presents a flowsheet that we developed and tested in a bench-scale pilot plant. It shows that a combination of mineral processing techniques, including comminution, heavy media separation, and flotation, can be successfully adapted to the recycling of post-consumer plastics. The gamma flotation process, which operates on the basis of solution surface tension control to facilitate the separation of inherently hydrophobic solids, combined with the alkali-treatment of a mixed polyvinal chloride-polyethylene terephthalate feedstock generates clean polymer concentrates at high recoveries.
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Characterization of Municipal Solid Waste: 1992 Update, EPA-530-R-92-019 (Washington, D.C.: EPA, 1992).
J.L. Holman, J.B. Stephenson, and M.J. Adam, Recycling of Plastics from Urban and Industrial Refuse, Report of Investigations 7955 (Washington, D.C.: U.S. Bureau of Mines, 1974).
M.H. Stanczyk and R.S. DeCesare, Resource Recovery from Municipal Solid Waste, Bulletin 683 (Washington, D.C.: U.S. Bureau of Mines, 1985).
E.G. Herkenhoff, “Mining and Processing Equipment Can Assist in Future Garbage Disposal,” Engineering and Mining Journal, 190(1) (1989), pp. 108–109.
K. Saito, I. Nagano, and S. Izumi, “New Separations Techniques for Waste Plastics,” Proceedings of the Fifth Mineral Waste Utilization Symposium (1976), pp. 322–328.
B. Yarar, “Investigation of the Recovery of Cellulose from Difficult to Process Sources, Using Surface Chemical Principles,” Proceedings of the 4th Recycling World Congress (1982).
V. Vogt and A. Bahr, “Flotation von Kunstoffen,” Erzmetall, 36(10) (1983), pp. 479–484.
D.B. Spencer, “New Technology Development in Plastics Recycling,” Proceedings of the 2nd International Symposium-Recycling of Metals and Engineered Materials, ed. J.H. van Linden, D.L. Stewart, Jr., and Y. Sahai (Warrendale, PA: TMS, 1990).
M.S. Super, R.M. Enick, and E.J. Beckman, “Separation of Thermoplastics by Density Using Near-Critical and Supercritical Carbon Dioxide and Sulfur Hexafluoride,” Emerging Technologies in Plastics Recycling (Washington, D.C.: American Chemical Society, 1992).
M. Poetzschke, R. Pfaff, and H. Sattler, “Basic Considerations on Post-Use Processing of Durables for Materials Recycling,” in Ref. 8.
P. Dinger, “Automated Sorting for Mixed Plastics,” BioCycle, 33(3) (1992), pp. 80–85.
S. Ottewell, “Processing Packaging Plastics,” The Chemical Engineer (November 1990), pp. 19–20.
B. Richards and A. Kumar Naj, “DuPont and Waste Management Plan to Build Largest U.S. Recycling Plant,” The Wall Street Journal (April 26, 1989), p. A4.
Aktieselskabet Nordiske Kabel-og Traadfabriker, “A Process for Non-Destructive Separation of Mixtures Containing Plastics and Non-Plastic Scrap,” international patent no. WO 83/02281 (7 July 1983).
Plastic Recovery Systems, “Process for the Separation and Recovery of Plastics,” international patent no. WO91/ 04100 (4 April 1991).
The Goodyear Tire and Rubber Company, “Process for Separating Polyethylene Terepthalate from Poly vinyl Chloride,” U. S. Patent No. 5,120,768 (9 June 1992).
“Plastics Recycling Plan Launched by Industry Group,” Chemical Marketing Reporter, 239 (13) (1991), pp. 5-6.
L.F. Diaz et al., eds., Composting and Recycling Municipal Solid Waste (Boca Raton, FL: Lewis Publishers, 1993).
W. Pearson, “Recycling Plastics from Municipal Solid Waste,” in Ref. 9.
A.J. Warner, C.H. Parker, and B. Baum, Solid Waste Management of Plastics (Washington, D.C.: Manufacturing Chemists Association, 1971).
B. Yarar, “’Gamma Flotation: A New Approach to Flotation, Using Liquid-Vapor Surface Tension Control,” Developments in Mineral Processing, ed. S.H. Castro and J. Alvarez (New York: Elsevier, 1988), pp. 41–64.
W.A. Zisman, “Relation of the Equilibrium Contact Angle to Liquid and Solid Constitution,” 20 Years of Colloid and Surface Chemistry. The Kendal Award Addresses, ed. K.J. Mysels, C.M. Samour, and J.H. Hillister (Washington, D.C.: ACS, 1973), pp. 109–159.
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Buchan, R., Yarar, B. Recovering plastics for recycling by mineral processing techniques. JOM 47, 52–55 (1995). https://doi.org/10.1007/BF03221410
- Municipal Solid Waste
- Waste Plastic
- Pulp Density
- Froth Flotation