Patent ID: 6903294

Claim:
A plastic sorting apparatus, comprising: a tribo-electrifying section for causing plural types of plastic pieces to frictionally contact with one another for electrification; and an upper-stage electrostatic separating section, a lower-stage electrostatic separating section and a recovery section all of which are located below the tribo-electrifying section downwardly in this order, wherein the upper- and lower-stage electrostatic separating sections each comprises a metallic rotationally-movable electrode having a top portion onto which plastic pieces are fed, an opposing electrode located to oppose a portion of the rotationally movable electrode which moves rotationally downward, and a high-voltage power supply that applies a high voltage to said rotationally movable electrode and opposing electrode to form a separating electrostatic field therebetween, a connection section is provided for feeding plastic pieces separated toward the rotationally movable electrode in the upper-stage electrostatic separating section to the rotationally movable electrode in the lower-stage electrostatic separating section, and polarities applied by the high-voltage power supply respectively to the rotationally movable electrode and the opposing electrode in the upper-stage electrostatic separating section are opposite to those in the lower-stage electrostatic separating section.