A new physical method, namely boiling treatment, was developed to aid flotation separation of acrylonitrile–
butadiene–styrene (ABS) and polystyrene (PS) plastics. Boiling treatment was shown to be effective
in producing a hydrophilic surface on ABS plastic. Fourier Transform Infrared analysis was conducted to
investigate the mechanism of boiling treatment of ABS. Surface rearrangement of polymer may be
responsible for surface change of boiling treated ABS, and the selective influence of boiling treatment
on the floatability of boiling treated plastics may be attributed to the difference in the molecular mobility
of polymer chains. The effects of flotation time, frother concentration and particle size on flotation behavior
of simple plastic were investigated. Based on flotation behavior of simple plastic, flotation separation
of boiling treatment ABS and PS with different particle sizes was achieved efficiently. The purity of ABS
and PS was up to 99.78% and 95.80%, respectively; the recovery of ABS and PS was up to 95.81% and
99.82%, respectively. Boiling treatment promotes the industrial application of plastics flotation and facilitates
plastic recycling.