INNOVATION | WEEE
Engineering plastics from WEEE: Separation challenge Polymers
ABS PS
ABS FR PS FR PC
PC/ABS PS/PPE PP PE PA PVC
Others
Technology Density
NIR Electrostatic
X-ray transmission Hand-held SSS/MIR
Unisensor laser spectroscopy XRF, LIBS, others Source: Fraunhofer IVV
Report, Electrolux said its use of recycled plastics had dropped to 5,600 tonnes in 2017. This is a reminder that the path to greater use of WEEE plas- tics is not straightforward. There is clearly a need for more work amongst
Below: A CloseWEEE project workshop at Gaiker’s facilities in Zamudio, Spain
recyclers and process technology developers to find solutions to the sector’s issues. “There is still research demand in this field,” said Martin Schlum- mer from Fraunhofer IVV. A major demand is for improved quality of the material to meet the expectations of OEM manufacturers wanting recyclate to replace virgin plastics. “There are many recycled grades on the market that are not good enough, so we have to improve it,” he said. Other development targets for the industry include: increasing yields to more than 60% of the recycled plastics in the raw material; focusing more on engineering plastics such as PC, ABS and PA; and producing compounds tailored to customers’ needs.
One of the biggest multi-partner projects in
Europe is CloseWEEE, funded by the EU’s Horizon 2020 programme, which is seeking solutions to problems of WEEE plastics recycling. Partners in the project are Fraunhofer IVV, Fraunhofer IZM, Coolrec, Gaiker, Tomra and Philips. Existing technologies for recycling WEEE plastics focus on polymers which are free of halogenated flame retardants, which neglects valuable materials such as PC-ABS. The project uses Tomra’s X-ray transmis- sion technology as its starting point to separate polymers, as the technology can produce a fraction of halogen-free polymers. This enables PC-ABS containing halogenated flame retardants to become concentrated into a fraction, and subse- quent sorting by a sink and float method enriches PC/ABS further to a purity of 80%. The CloseWEEE project has investigated the use
of the CreaSolv solvent process to purify fractions from mixed WEEE plastics streams (CreaSolv is also being used for recycling of PVC and multi-layer pack- aging). The process steps are: dissolution, purifica- tion, precipitation and drying. “The good news is that we can not only remove contaminants like copper, but we can also take out flame retardants,” said Schlummer. The result is a granule that is “very close to virgin”, he said. In an example he gave of mixed ABS and polystyrene containing flame retardants, the CreaSolv process results in two outputs: PS and ABS, both still containing antimony trioxide from the flame retardant which is then removed in a centrifuge, leaving the polymers in a purified state. Optical sorting technologies can be used in the sorting of WEEE polymers, but one of the limita-
30 PLASTICS RECYCLING WORLD | March/April 2018
www.plasticsrecyclingworld.com Chances
Enrichment of polymer types and grades (eg BFR and BFR-free)
Separation by polymer type. Industrial availability
Separation of ABS and PS from BFR-free density fraction
Separation of BFR and BFR-free Separation by polymer type
Separation by polymer type. Industrial availability. Separation of black
Separation of BFR and BFR-free
Limitations
Unspecific High material diversity in heavy fractions
No separation of black plastics No separation of BFR and BFR-free
Only mixtures of limited compositions No separation of BFR
No separation by polymer type
Not automatic No separation of BFR and BFR-free No separation of BFR and BFR-free
Limited industrial availability. Not state of the art
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