Application Of Mineral-Processing Technology To Plastics Recycling

Mineral-processing techniques were adopted for use in the separation of various plastics used in beverage bottles. A complete flowsheet, which utilized size reduction, heavy-media separation and flotation, was developed to separate PE, PVC and PET. In addition, the mixtures contained cellulose fibers (from labels) and aluminum (from bottle caps). It was demonstrated that, while heavy-media separation allows for the separation of a PVC/ PET mixture, froth flotation can be used to separate PVC and PET. For this purpose, the differential action of a pH 11 alkaline aqueous solution containing methanol and MIBC as surface-tension control agents, has been found to be a suitable flotation medium. This paper reports on some aspects of a flotation flowsheet that was developed for the separation of plastics contained in municipal solid wastes.