Experimental Investigation of a Roll-type Tribo-electrostatic Separator for Granular Waste Plastics

The aim of the present study is to evaluate several possibilities of preconditioning a mm-size granular mixture of waste plastics, in view of its electrostatic separation. The experimental set-up was composed of an inclined-rotating cylinder-type tribo-charging device associated with a roll-type electrostatic separator. The experiments were performed a mixture of mm-size PP and HIPS granules provided by a waste plastics recycle, provided by a waste plastics recycler. In distinct series of experiments, the genuine material was subjected to additional grinding, followed or not by charge neutralization. It was found that feeding the plastic mixture into the tribo-electrostatic separation unit right after grinding gives the best results: the purity and the recovery rates of the products exceed 96 %.