Study the effects of flotation agents on ABS – PS flotation

Abstract

Abstract The use of appropriate flotation agents is mandatory to effectively separate plastic mixtures with analogous physicochemical characteristics by flotation. In this study, both virgin and post-consumer ABS and PS plastics were chosen as research objects to investigate the effects of flotation agents in ABS – PS flotation and an appropriate condition was then identified for effective separation. The wetting behaviors of wetting agents on ABS and PS surfaces were further studied. As a result, TA demonstrated better selective performance than LS in ABS – PS flotation due to its selective wettability on the ABS surface, referring to a greater surface free energy and a stronger repulsive interfacial interaction. Additionally, laureth-5 was found to be used potentially as a frother in ABS – PS flotation as well as MIBC; however, its application was limited at high concentrations due to its tendency to rapidly reduce surface tension. These findings suggest that the selection of a suitable frother for ABS – PS flotation should not only consider the ability to produce fine bubbles and stabilize the froth but also the ability to reduce the surface tension of the liquid medium. Overall, high recovery and purity of both virgin and post-consumer ABS – PS flotation were achieved by more than 90% under the conditions of TA concentration of 5 mg/L, MIBC concentration of 5 mg/L, and conditioning time of 15 minutes.