Recycling with an eye on precision

Germany-based recycling and sorting technology provider Sesotec GmbH is working with Austria-based Steinbeis Polyvert GmbH to help that company convert postconsumer plastic scrap into several marketable grades.

Steinbeis Polyvert was founded in 1956 and has production facilities in Austria and Germany.

“Our recycling solutions for polyethylene terephthalate (PET), high-density polyethylene (HDPE) and polypropylene (PP) plastics are continuously developed and optimized at Steinbeis Polyvert," Sesotec says, adding it has helped Steinbeis Polyvert become a producer of “top-quality plastic granules" that can be used in a wide range of product applications.

Considerable research went into the planning of a new sorting line for Steinbeis Polyvert.

“After extensive sorting trials with different material compositions at the Sesotec Technical Center in Schönberg, the sorting processes were collaboratively developed and successfully implemented," Sesotec says.

At a Steinbeis Polyvert facility, material processing begins with bale breaking. After removing ferrous metals, air classification and ballistic separation, material is divided into pure fractions.

Varisort and Unity devices address both preliminary sorting and final cleaning of inbound material and are deployed to recover materials from previously generated reject fractions. A Sesotec Varisort+ Flex arrangement enables online analysis of incoming materials from previous processes.

“This occurs alongside the ongoing sorting program, providing real-time insights into the material’s composition and color,” Sesotec says.

The sorted material fractions are then shredded and washed. The flakes proceed through additional separation stages to the final optical sorting phase, where Sesotec's Flake Purifier+ systems come into play. Those systems remove off-color flakes, unwelcome plastics and residual metals, creating PP and HDPE flakes.

Steinbeis Polyvert also deployed Sesotec’s Flake Scan analysis system, placed before extrusion and at other sorting stages. The system evaluates the quality of plastic flakes in minutes, enabling rapid, reliable decisions on material usability, according to Sesotec. Samples scanned by Flake Scan are analyzed for foreign plastics, off-colors and metals.

Next, the plastic flakes are extruded on-site into plastic granulate or pellets that is ready to be used in the manufacturing of new products.

“With Sesotec, we have a reliable technology partner that supports our recycling processes with flexible and precise sorting and analysis systems, meeting the highest quality standards of our customers,” Steinbeis Polyvert Managing Director André Aßmann says.

At a Steinbeis Polyvert facility in Austria, Sesotec says it is pioneering the use of its latest Sesotec multisensor sorting systems, enhanced with artificial intelligence or machine learning capabilities that can detect black objects on black conveyor belts and distinguish materials that traditional color evaluation technology struggles to differentiate.