the addition of DnOP enhances the flotability further. However, the addition of CaCO3 changes markedly the flotability of PVC plastic.The flotation recovery remains 100% when the percent of CaCO3 isless than 20 wt.%, and then decreases remarkably with increasing of the CaCO3, which can be attributed to that the addition of CaCO3 enhances the hydrophily of plastic, and thus reduces the flotability.The natural flotability of waste PVC plastics were further stud-ied, and the result is demonstrated in Fig. 4b. The flotation recoveryof PVC-dec, which contains larger percent of CaCO3, is considerably small, while that of PVC-sho containing larger percent of DnOP is 100%. From the infrared spectrum (Fig. 5) of the two waste plastics,it is observed that CaCO3and DnOP have a great impact on the PVC plastics. Therefore, it can be concluded that the PVC plastics were influenced significantly by the additives.