Recycling: New process can recognize black plastic
Sorting plants in recycling usually do not recognize black plastic, which is why it is sorted out instead of being recycled. A new process is to change this.
Black and other colored plastic waste
(Image: mann7429 / Shutterstock.com)
In the future, black plastic should also be recycled: According to their own statements, a team at the Fraunhofer Institute for Non-Destructive Testing IZFP has developed a method to recognize black plastic in a sorting plant and feed it into recycling.
The team led by Andreas Keller and Kevin Schmitz uses artificial intelligence (AI) and thermography to identify black plastic. Current sorting processes often lack the necessary detection technology, which is why it is not recycled but thermally recovered -- meaning it ends up in an incineration plant.
The setup includes an infrared heater that slightly warms the plastic. A thermal imaging camera captures the parts, from which thermal signatures are then generated. An AI model analyzes these in real time and sorts them accordingly.
According to the Fraunhofer researchers, the system is capable of detecting the signatures of some types of black plastic: To date, it reliably recognizes polyamide (PA) and polypropylene (PP).
Team presents demonstrator
At the Solids & Recycling-Technik trade fair, the Fraunhofer team will present a prototype system that works with this technology. "Our demonstrator clearly shows how we can enable cost-effective sorting of black plastics using active thermography and artificial intelligence," say Keller and Schmitz. "This creates an important basis for closing the loop for these challenging materials as well. In doing so, we can save valuable resources and reduce COâ‚‚ emissions at the same time."
The detection of black plastic is a problem in the recycling industry. Systems that can do this are comparatively expensive -- more expensive even than the Fraunhofer process. For the systems currently used widely, transparent or colored plastic products can be recognized, but not black ones. The latter include, for example, packaging, sports equipment, many components from cars or the electronics industry.
If these could be automatically recognized on an industrial scale in the future, valuable raw materials could be recovered in large quantities, which would also save carbon dioxide emissions, the Fraunhofer IZFP announced. The relevance of this development is therefore significant.
Next, the team wants to further develop the system so that it recognizes plastics other than PA and PP and becomes faster. The goal is to prepare it for industrial use.
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The Solids & Recycling-Technik trade fair will take place on March 18 and 19 in Dortmund.
(wpl)
