Electrostatic Separation of the Shredded Plastic Mixtures Using A Tribo‐Cyclone

Abstract

In this experimental work, artificial plastic mixture of two kinds of components (i.e. PET and PE mixture) is tribo-electrostatically separated. The mixture is charged by friction in a tribo-cyclone.After a certain residence time inside the tribo-cyclone, the charged plastic flakes fall down freely through a horizontal electric field into collection bins. The DC electric field of up to 333 kV/m is created by using two plate electrodes made of Cu and having a given cross-section configuration. The plastic flakes of the mixture are drawn to either positive or negative electrode according to the polarity of the charge and are separated by falling into different bins. In order to ensure an easy and efficient separation, the inner wall of the tribo-cyclone is made of a suitable plastic material to improve the frictional charging of the flakes. Each plastic component is separated with a grade higher than 95% and recovery higher than 75%.

Plastics Recycling – Technology and Business in Japan

“…Waste plastics, especially polyethylene, propylene, polystyrene, PET and PVC, are exported to China over some 1.5 million tons per year. In 2011, 1.6 million ton of waste plastics of commercial values were exported to mainly China for mechanical recycling (Table 7) [25]. China's country share as the exporting destination is 1.48 million ton (90.5 % of total exported amounts from Japan), which includes the mainland 890 thousand ton and Hong Kong 586 thousand ton.…”

Combination of Triboelectrostatic Separation and Air Tabling for Sorting Plastics from a Multi-Component Plastic Mixture

“…Detailed experimental procedures and analyses of the performance of triboelectrostatic separator and air table respectively have been already reported and discussed separately in previous articles. 12,13) Table 2 summarizes the influence of each operating parameters on the behavior of material processed by each separator showing the (Fig. 9).…”

“…A mathematical model for this specific triboelectrostatic separator has already been developed 13) and expressed as follows:…”

“…Flotation [5][6][7][8][9] and sink-float 10,11) separation techniques are well-known wet methods for sorting plastics. On the other hand, many kinds of binary plastic mixtures are separated with high purity by dry methods such as pneumatic separation using air table, 12) and electrostatic separation using tribo-cyclone, 13) friction mixer with rotary blades, 14) fluidized-bed triboelectrification, 15) or vibrating feeder. 16) Being dry methods, they have a clear advantage over wet ones, as they do not require treatment of water from the process for reuse or discharge, expensive wetting reagents, and most importantly, dewatering or drying the mixture after separation.…”

Separation Performance of PVC and PP Plastic Mixture Using Air Table

“…Flotation [3][4][5][6], and sink-float [7,8] separation techniques are well known wet methods for plastic separation. Moreover, many kinds of plastics have been separated with high purity by electrostatic separation using friction mixer with rotary blades [9], tribo-cyclone [10], fluidized-bed triboelectrification [11], or vibrating feeder and electrostatic high voltage generator [12]. Additionally, the pneumatic separation, a dry mechanical process, is another method of separation.…”