Abstract: The history and recent advances of plastics flotation were reviewed in this paper. Based on the mechanism of plastics flotation, the methods of selectively plastics wetting could be divided into wetting through adsorption, surface oxidation, wetting through absorption, and gamma flotation. At present, the developed methods of plastics flotation were mainly gamma flotation, flotation by physical conditioning and flotation by chemical conditioning, which are based on liquidvapor surface tension control, surface modification through physical techniques and adsorption of wetting agents, respectively. The methods of physical conditioning included such techniques as plasma treatment, flame treatment, ozone oxidation, particle control, wet oxidative chemical reactions and corona discharge. The common wetting agents used in chemical conditioning were methylcellulose, calcium lignosulphonate, and tannin.

Key words: waste plastics, plastics flotation, wetting mechanism, surface oxidation, flotation reagent