STF Recycling GmbH chose Bühler’s two-machine solution to achieve a higher grade rPET which can be re-used in the bottle-to-bottle industry. Mr Söllner from STF applauded Bühler for its ability to remove foreign materials (FM) that can devalue rPET, such as opaque defects, wood, metals, other FM and non-PET. Speaking about the solution, Mr Söllner said: “We chose to use SORTEX® as it is the best flake sorter in the market. Bühler has also introduced us to its partner, US-based National Recovery Technologies (NRT), which is now supplying us with bottle sorters, at the front end of our production line.”

The two-machine solution incorporates the SORTEX A ColorVision™, which delivers superior colour sorting thanks to its use of three visible wavelengths, allowing for excellent colour detection. When combined with enhanced InGaAs camera technology, an advanced inspection system and SmartEject technology, the sorter efficiently removes challenging foreign material from clear, blue, green and jazz applications.  Then the SORTEX E PolyVision™ employs a revolutionary polymer sorting process, using a unique combination of transparent and reflective sorting, simultaneously. This identifies invisible and same-colour polymer contaminants by their unique chemical signature, successfully separating clear polymers from clear PET. This combination delivers higher grade rPET flakes that exceed the minimum standards for re-use.

Mr Söllner added: “PET recycling is a very complex multistage process that requires efficiency at every point. Our ultimate aim is to continue to increase output quality, while at the same time minimising the loss of valuable and re-usable product in the reject stream. We undertook several industry trials to evaluate other technologies on the market but discovered that Bühler provided the best solution. First class machine results combined with impressive customer service and a commitment to ongoing development meant it was the only optical sorting solution for us. We highly recommend Bühler’s SORTEX® technology.”

Since its launch, Bühler’s two-machine solution has rapidly gained market acceptance and industry recognition from recyclers and OEM’s, as a ground breaking development in FM sorting, particularly with its capability to identify difficult to detect polymers. Not only does it complete the company’s rPET sorting portfolio, but it positions the business as a leading supplier for colour, FM and polymer removal. In just five months, it has been sold to factories across Europe and North America. Further installations, similar to the one in STF Recycling, are expected to be confirmed in 2017.

STF Recycling processes 130,000 tonnes of PET bottles each year, from which it makes rPET flakes and pellets that are bottle-to-bottle grade. One of the biggest challenges faced by the company is the constantly changing input composition of materials to be sorted and recycled, with ever narrower output specifications. This includes more metals from beverage cans, as well as bottles with multilayers, sleeves and labels from PVC, PS, PC and PET-G plastics. The company, which has installed over 70 turnkey plants worldwide, has now integrated Bühler’s two-machine solution into its portfolio, enhancing its own offering.  

Mr Söllner from STF, concluded: “We have seen many companies that claim to be the best. The Bühler team came to me saying it could deliver the best. I said, if you can prove to me that you have the best technology, then I will buy it. To be honest, we had never thought about Bühler – so thankfully the company came to me – and I’m glad they did.”