Experimental analysis and optimisation of a free-fall triboelectric separator of granular plastic particles

Abstract

Among the separation techniques used in industry, the triboelectric separation of insulating particles using rotary tube is an efficient technology employed in waste recovery and mineral industries. This process, also called free-fall triboelectric separation, is widely used for the sorting and the purification of granular materials resulting from industrial plastic wastes. This paper aims to achieve a comprehensive description of the laboratory triboelectric separator built up by the authors, and its utilisation for an experimental study carried out on granular samples containing particles of polyvinyl chloride and polyethylene. Thus, among the variable factors of the process, we analysed the influence of the most important ones, i.e. the rotational speed of the cylinder n (rpm), the applied high voltage U (kV), the charging time of the particles t (s), the mass of the sample m (g) and the composition percentage of the sample C _p (%). Furthermore, the output process was optimised using the methodology of experimental designs. The obtained results are very instructive and confirmed the efficiency of this separation method for the processing of industrial plastic wastes.

Keywords:

• electrostatic separation
• triboelectricity
• high voltage
• plastic wastes