Charge-decay electrostatic separation for removing Polyvinyl chloride from mixed plastic wastes

An innovative recycling method charge-decay electrostatic separation (CDES) has been developed to remove PVC from mixed plastic wastes. According to the charge-decay properties experiments of ABS, PP, and PVC, three charge-decay patterns were found. Computer simulation was used to investigate separation possibility. The differences in the charge-decay properties of different non-conductors provided the technical basis for developing the CDES. The separation resulted by virgin mixed plastics indicated that long decay time was beneficial to remove PVC from ABS or PP. The PVC removal rate increased from 50% to 100% with the increased decay time. When separating mixed plastic wastes from waste refrigerator, the purity of PVC can reach 96% and removal rate was 99% after single round separating. The separation condition was set as following: voltage of corona-electrostatic electrode (V1) = −20 kV, voltage of round electrostatic electrode (V2) = 20 kV, decay times (t) = 300s. CDES is a promising way to separate mixed materials with difference in charge-decay rate.