Recycling together makes mixed waste streams interesting

Impact-resistant, heat-resistant and flame-retardant: polycarbonate is all of these things. It is also transparent, making it an ideal substitute for glass. This incredibly versatile polymer is widely used in cars, electronics, toys and appliances — almost always in combination with other materials, which makes recycling polycarbonate a challenge. To recycle mixed waste streams containing this plastic in an economically viable way, polycarbonate producer Trinseo is looking for partners interested in recovering those other materials.

Magnets, for instance, are currently attracting considerable attention when it comes to recycling. Typically, magnets consist of 70 per cent iron, alongside various rare earth metals such as neodymium, praseodymium, samarium and gadolinium. Magnets are widely used in cars, electronics, medical equipment and wind turbines. Cars contain approximately 1.5 kilograms of magnets, and wind turbines 10 to 11 tonnes. The European market is estimated at around 25,000 tonnes per year and is expected to double by 2030–2035. At present, 95 per cent of magnets are produced in China. In response to this increasingly unwelcome dependency, they have been included in the European Critical Raw Materials Act: by 2030, 25% of the EU’s annual requirements must come from domestic recycling.

‘In a linear business model, we would never have met’

Ben Porter, Trinseo

Headlamps

Trinseo recently signed an agreement with French start-up MagREESource to accelerate the recycling of mixed streams of polycarbonate and magnets. It is a remarkable collaboration, says Ben Porter, Global Sustainability Business Development Manager at Trinseo. ‘Although our products — plastics and magnets — can both end up with the same type of customer, in a linear business model we would never have met.’ Establishing a robust circular ecosystem requires parties from different industries to come together at the same table, and Porter acknowledges that this remains a challenge. ‘Car headlamps are made up of a large number of different materials. You have to disassemble that headlamp step by step and recycle the materials in a cascade. You have to reinvent the recycling ecosystem.’

Dissolution

Trinseo has developed a recycling technology for polycarbonates based on dissolution: the polymers in the waste stream selectively dissolve in a solvent, leaving residual materials behind. Dissolving polymers is not new, but it remains relatively unfamiliar in the context of recycling, says Porter. ‘There is a common assumption that the waste stream must first be shredded, but that is not necessary at all. In principle, you can put polycarbonate sheets, as well as chargers from electrical appliances or keyboards, for example, into the dissolution unit whole, without any pre-processing. Dissolution recycling is far more forgiving when it comes to contamination than mechanical and chemical recycling, owing to its selective solubility.’

The dissolved polycarbonate precipitates as cotton-like flakes. Because their density is very low, an additional compaction step — compounding — is carried out. The material can then be used alongside virgin polycarbonate. ‘We have demonstrated that it can be used in combination with ABS in components for the automotive industry, for lighting, and in electronics.’ The residual materials are available for recycling by other parties, such as MagREESource in this case.

Powder particles

MagREESource is one of the few European companies with expertise in recycling magnetic materials, says co-founder Erick Petit. ‘Over the past 40 years, we in Europe have forgotten that we possess knowledge of metallurgical processes. In France, you can count the experts in rare earth metals on the fingers of your hands, whereas in China there are thousands.’

MagREESource holds a patent on its process for purifying magnetic waste prior to recycling, says Petit, without revealing many details. The purified metal is then treated with hydrogen. ‘Rare earth metals can absorb hydrogen, in much the same way that wood absorbs water.’ And just like wood, the material swells, and once saturated, it breaks apart into a powder with particles of just a few microns in size. ‘Smaller particles can be better aligned. That means they all have their north and south poles pointing in the same direction, and that determines the quality of the magnets.’ The powder is then sintered under pressure and at a temperature of 1,000 to 1,100 degrees into new magnetic material.

‘We have forgotten in Europe that we possess knowledge of metallurgical processes’

Erick Petit, MagREESource

MagREESource’s process currently operates on a small scale, at 50 to 80 tonnes per year. The company has advanced plans for a larger-scale facility — the first MagFactory — with an initial production capacity of 1,000 tonnes per year. In October, the company will begin applying for the necessary (construction) permits. Petit hopes that construction of the plant can begin in mid-2026, with operations potentially commencing in 2028.

Offtakers

Trinseo has made considerable progress in recent years in the dissolution recycling of polycarbonate. Since 2023, the company has operated a pilot plant in Terneuzen, which has now reached TRL7 status and can recover several hundred kilograms per batch. The company is working towards establishing a commercial plant in China. This will be a modest-sized facility, but it will nonetheless be the first plant with a capacity measured in kilotonnes.

Porter sees real potential for this type of plant in Europe and the United States. ‘When choosing a location, we look at where waste streams are available, whether there is regulatory support and political interest in recycling, and whether there are parties willing to offtake the products.’ This also involves legislation such as the aforementioned CRM Act and the new European End of Life Vehicles Directive, which comes into force from 2030–2031. Under the latter, a greater proportion of the materials used in vehicles will need to be recycled. Collaborations such as that between Trinseo and MagREESource are, in any case, a step in the right direction.