Technology details Brief description of the process: Mixed post-consumer plastic packaging waste enters the sorting process as bales. After the wires around the incoming bales have been removed, shredders and bag openers installed at the beginning of each sorting line are used to separate the compressed bales into individual packaging pieces. It is key for the efficiency of the sorting process that the material is well separated and evenly dispersed on the conveyor belts. Once the material has passed the shredders, magnets mounted above the conveyor belts remove magnetic metal objects. The material stream is then separated in several sub-streams by size, through trommels with different-sized holes along the axis, followed by disc screens and vibrating screens separating and removing the smallest objects. The size-sorted material passes a combination of vacuums and ballistic separators to separate films/flexible plastic and rigid plastic. NIR-sensors in several steps are then used to detect targeted plastics as well as non-targeted material (e.g. paper) across the conveyor belt through Near-Infraredlight, and according to the reflected spectrum sort the targeted materials via pneumatic ejection. Depending on the specific sorting task, each NIR sensor has a relevant configuration. To increase quality of the sorted material, there are (at least) two step NIR sorting for each fraction: the first step aims at picking out the targeted plastic fraction, the second step aims at identifying and removing anything that is not the targeted stream. The NIR-technology cannot distinguish black plastic from other contaminants, so lasers are used to detect and recover black plastic objects from the reject streams.
To improve the recyclability of the sorted material, cameras with AI - deep learning camera system) are used to remove certain packaging types in some of the mono streams (e.g. plastic packaging that might contain product residues which are problematic for the recycling process). The sorting line is also equipped with recovery units, which can detect and return incorrectly separated material to an earlier step in the sorting process. Bunkers storing the sorted fractions are emptied automatically, and the sorted material is then re-baled.
List of key technological components:
- shredders
- bag openers
- magnets for removal of wires and other magnetic metal objects
- trommels, sieving the material through a drum screen with different-sized holes to separate the material by size
- disc screens separating objects between 15 and 50 mm from the larger objects
- vibrating screens removing pieces or objects smaller than 15 mm
- vacuum units, separating larger pieces of film from rigid plastic through vacuums mounted over the conveyor belts
- ballistic separators, separating the material into plastic film and rigid plastic
- NIR Autosort sensors with associated pneumatic ejection, identifying and sorting (ejecting) the different targeted plastic types
- balers
