Abstract: The aim of this study was to separate waste plastics ABS and PS. The effects of parameters such as wetting agent, froth agent, conditioning time, flotation time etc. on flotation behaviors of ABS and PS were investigated in an especially designed dissolved-air flotation column and the optimized separation conditions were gained. The results showed when using 25mg/L wetting agent tannic acid, 5mg/L froth agent terpineol and conditioning time 15min, flotation time 15min, mixtures of waste plastics ABS and PS were separated successfully by dissolved-air flotation technique and the results revealed that the purity and recovery of PS in the floated was 90.12% and 97.45% respectively, the purity and recovery of ABS in the sank was 97.24% and 89.38% respectively. The study also showed that to overcome the adverse effects of mixed plastics in flotation process, further systematic research on interaction between plastic particles was important in this field.

Key words: plastics flotation, dissolved-air flotation (DAF), waste plastics, wetting agent