Experimental Analysis of a Cyclone Tribocharging Device for Free-fall Triboelectric Separation of Plastic Particles

A cyclone can be employed as tribocharging device for free-fall electrostatic separation of granular plastic mixtures. The objective of this work is to validate the possibility of modifying the "standard" operation of such a device, so that the turbine of the cyclone to participate in the charging process of the granules. Thus the granular product is introduced through a funnel into the turbine and then blown into the cyclone. When processed independently in the cyclone tribocharger, the charge acquired by the granules is significantly higher than in a fluidized bed device. On the contrary. when mixtures of granules are introduced into the tribocharger, the electrostatic separation efficiency is lower than with the latter device. However, the efficiency of the triboelectrostatic separation increases when covering the inner wall of the cyclone with a material that is located in the triboelectric series in-between the plastics to be sorted.