The use of hyperspectral imaging technology to sort black plastics by polymer class, continues to be a hot topic…

30 March 2017

STEINERT recently presented at IdentiPlast in Vienna and also at the Berlin Recycling and Raw Material Conference – highlighting technologies for sorting black plastics

Ernie Beker (left), Sales Manager at STEINERT, talking after his presentation Source: IdentiPlast

The 13th International Conference on the Recycling & Recovery of Plastics, ViennaSource: IdentiPlast

The recycling industry puts high demands on sorting technology

Not only are machine capacities and throughput rates increasing, but also the demands on sorting performance. These aspects affect sensor technology as well as the sorting functions of the machines themselves. What’s more, operators of recycling systems increasingly want higher recycling rates as well as lower amounts of residual waste after the recycling processes are completed. Sensor-based sorting technology is indispensable for the development of a sustainable recycling economy and the attainment of ambitious EU targets such as the ban on the disposal of non-biodegradeable plastics or the achievement of a 75-percent recycling rate for plastic packaging by 2030.

Germany has fully developed solutions for almost all industrial waste sorting tasks involving polymer materials. These solutions are increasingly being accepted and used by the players along the recycling chain. However, the sorting of soot-blackened plastics by polymer class is still a very challenging task whenever the swim-sink method cannot be used. RTT Steinert GmbH, a subsidiary of STEINERT Elektromagnetbau GmbH, has addressed this issue for some time now and developed a solution to the industrial production stage.

Highly advanced sensors that use hyperspectral imaging (HSI) technology.

At many recycling facilities, black and dark objects that do not fall into a defined spectrum as well as very soiled plastics often end up in the residual fraction, which generally prevents them from being fed back into the raw-material cycle. However, this particular technology does not use mechanically moving parts and it scans the entire width of the conveying system in one go with a high-resolution line-scan camera. The market-ready product UniSort Black enables operators to also detect such objects in the flow of materials and supply them to the plastic-processing industry.

The clean separation of black parts

The UniSort BlackEye closes another gap in the sorting process: the clean separation of black parts This sorting machine doesn’t separate plastic flakes on the basis of their colour, but their polymer class. Therefore, the UniSort BlackEye can cleanly separate not only black plastics, but plastics of any colour. As a result, it is now possible to efficiently recover recyclates from fractions with a high proportion of dark plastics.