Method for Removing Impurities from Shredded Plastic

A method for removing impurities from shredded plastic using a device, which comprises a first cleaning disc (10) with a first cleaning surface (12) and a second cleaning disc (40) with a second cleaning surface (42), wherein the cleaning surfaces (12, 42) lie opposite each other and border a cleaning gap (44) between each other, the method comprising the following steps:

• at least one of the cleaning discs (10, 40) is rotated around its rotational axis,
• liquid, in particular water or an aqueous solution, is fed into the cleaning gap (44),
• shredded plastic to be cleaned is fed between the cleaning discs (10, 40) and conveyed through the cleaning gap (44), wherein the surfaces of the shredded plastic are processed abrasively by the first and second cleaning surface (12, 42),
• the temperature difference between the temperature of the liquid guided through the cleaning gap (44) during entry into the cleaning gap (44) and the temperature of the liquid guided through the cleaning gap (44) during exit from the cleaning gap (44) and/or at least one parameter characterizing this temperature difference is measured,
• the distance between the cleaning surfaces (12, 42) is set such that the measured temperature difference and/or the at least one parameter characterizing this temperature difference comes as close as possible to a setpoint value.