Purification of polyethylene terephthalate from polyvinyl chloride by froth flotation for the plastics (soft-drink bottle) recycling industry

Strong alkaline solutions of sodium hydroxide are able to destroy the hydro phobicity of polyethylene terephthalate (PET) allowing for the flotation se paration of PVC (polyvinyl chloride) from PET. Conditioning of the PVC/PET mixture in a low-concentration solution of polymer plasticizer at elevated temperature enhances the hydrophobicity of PVC particles and only slightly affects the surface properties of PET particles. On this basis, enhancement of the flotation separation by conditioning with a polymer plasticizer, an d by the use of non-ionic surfactants, has been developed and tested at a l aboratory scale. Using this procedure a 93-95% recovery of PET can be obtai ned while rejecting almost all PVC (98-100%). (C) 1999 Elsevier Science B.V . All rights reserved.