Selective froth flotation of PVC from PVC/PET mixtures for the plastics recycling industry

Abstract It was found that strongly alkaline solutions of sodium hydroxide are able to destroy the hydrophobicity of polyethylene terephthalate (PET) whereas the hydrophobicity of polyvinyl chloride (PVC) remains only slightly affected by these solutions. On this basis, a technology involving treatment of PET and PVC particles with alkaline solutions followed by froth flotation of PVC with nonionic surfactants has been developed and tested at a laboratory scale. In both steps of this technology, appropriate experimental conditions, such as concentration of reagents, temperature and residence time, have been optimized through a detailed examination of all these variables on the efficiency and selectivity of PVC separation from PVC/PET mixtures of varying composition. It is demonstrated that using this technology 95–100% recovery of PET and PVC can be achieved in separate products from a variety of PVC/PET mixtures.