Experimental Comparative Study of Different Tribocharging Devices for Triboelectric Separation of Insulating Particles

Several tribocharging devices are commonly used for charging insulating particles in order to separate granular plastic mixtures using a vertical triboelectric separator. However, there is no comparative analysis of these devices when tribocharging is achieved using identical samples of insulating particles. The objective of this paper is to carry out an experimental study that compares several tribocharging devices built up in the laboratory: a rotating cylinder, a tribo-cyclone, a static tribocharger, a propeller-type unit, and a fluidized bed. The study was performed using two granular samples of polyvinyl chloride (PVC) and high-density polyethylene (HDPE), for two different particle sizes: 1 and 2 mm. Experimental results showed that, when tribocharging pure samples of either PVC or HDPE, tribo-cyclone is the most efficient. However, when mixed samples are processed, the fluidized bed device gives the best results in terms of electric charge and separation efficiency.