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Recovery of PC/ABS from WEEE Plastic Shred by the CreaSolv® Process

Last September 7th – 9th the Electronic Goes Green 2016 Conference was held in Berlin. Electronics Goes Green is the world’s leading conference on electronics & environment that offers an opportunity to show results and innovative green solutions. The event also showcases the future trends and solutions towards sustainable development in the electronics sector.

Waste of electrical and electronic equipment (WEEE) contains a series many of valuable materials and substances and some of them are currently not recycled properly. The Fraunhofer IVV aims to close the loop for PC/ABS from housing polymers coming from WEEE. Martin Schlummer presented the current state of the work at the Conference Electronic Goes Green 2016 in Berlin. The results show that the solvent-based CreaSolv® Process can be applied to selectively dissolve PC/ABS from mixed WEEE plastics fractions. After separation of non-target materials pure PC/ABS is recovered from the polymer solution whereas the solvent is recycled within the process.

Fraunhofer IVV and partners in the CloseWEEE consortium held presentations in the event.

Find the articles presented by Fraunhofer below:

Recovery of PC/ABS from WEEE Plastic Shred by CreaSolv® Process

As of 2010 Eurostat reported that 3.3M tonnes of WEEE is collected in the EU annually. Many components of WEEE effective recycling technologies have already been developed and put into practice (e.g. copper, gold, polypropylene, polystyrene) there are significant valuable components which are not exploited yet.

These include PC/ABS, plastics used as standard casing material for modern consumer electronics. PC/ABS is currently collected with halogen-rich WEEE plastics and not recovered yet. The recovery of PC/ABS as a secondary polymeric raw material is highly challenging as even small shares of foreign materials cause significant negative effects on mechanical material properties.

Currently, the European CloseWEEE project investigates innovative sorting and recycling techniques capable of recovering highly pure PC/ABS.

This paper presents results indicating that pre-treatment of mixed shred of WEEE by x-ray transition (XRT) and density sorting enables an effective pre-concentration of the target polymer PC/ABS. XRT provides a fraction of halogen-free polymers, whereas subsequent sorting by a sink and float approach enriches PC/ABS further to a purity of 80%. The chain of purifying processes is finalised by the solvent-based Creasolv® process.sankey_web

Recovery of Bromine and Antimony from WEEE Plastics

Current technologies for recycling plastics from WEEE aim at the major polymer types, i.e. ABS, PS and PP, which are free of brominated flame retardants (BFR), are separated from the mixed plastics stream by means of density separation and/or spectroscopic sorters and leave a fraction containing significant amounts of flame retarded ABS, PS.

As high industrial consumption faces limited supply and accessibility, antimony has been identified as a critical element in the EU and therefore is an interesting target element in urban mining approaches. Separation of fraction of concentrated BFR free of metals enables bromine recovery from those fractions in pyrolytic processes producing bromine for new and safe bromine-based flame retardants (like PolyFR).

The technological approach of the project bases on a dissolution based recycling concept (CreaSolv) that allows to selectively extract ABS and PS from the halogen fraction. At the current project stage, the technical feasibility of this approach has been demonstrated in laboratory scale. It has been upscaled recently to small technical scale using a decanter centrifuge. Results show, that application of centrifugal forces separates Sb2O3 to more than 90 % from the dissolved polymers whereas BFR stay in solution.