LONDON The Sims Group, which operates the World’s largest fridge recycling plant in Newport processing over 600,000 fridges a year, has developed a system for recycling plastics used in electronic products.
The company says the majority of electronic equipment contains a high proportion of plastics. Approximately 12,000 tonnes of plastic are recovered each year from the recycling of end of life fridges and when the Waste Electrical and Electronic Equipment (WEEE) directive comes into force in November, a further estimated 200,000 tonnes of plastics will come under scrutiny.
Although mostly considered as a non-hazardous material, unless plastic can be recovered for recycling, recycling and recovery targets for WEEE may well be missed according to Sims.
The UK has been recycling plastics for some time usually in the form of bottles and cups containing only a few polymers, whereas the plastics in electrical items are higher in number and worst, contaminated with metal, rubber, wood and glass.
This creates an issue, as many polymers are incompatible with each other and current recycling and recovery processes for WEEE result in the retrieval of a mixture of polymers. This mixture subsequently has few uses and as a result, if it can avoid landfill, often ends up as aggregates or is “glued” together with resin to form low-grade composite materials.
This quality issue is further compounded if the material contains any non-plastic contaminants, such as metal and glass, and as such this recovered plastic currently has low value markets that can be difficult to sustain. As such there is a real incentive ahead of the WEEE directive to give manufacturers comfort that plastics as well as metals will be recovered to the highest possible levels at greatest commercial value, thereby helping them lower their overall cost burden under legislation that will see a rise in production costs.
Dr Richard Hooper, a materials technologist and head of research and development of the Sims Group’s, said, “Plastic’s are one of the most abundant materials in Electrical Equipment, our current technology allows us to recover all metals from WEEE and in essence what we have achieved is the first steps in taking the sorting technology for polymers to the same level as the sorting technology for metals. We have developed a density separation process that produces higher quality products which have better value and can achieve more easily sustainable markets.”
The Sims Group process uses a three stage density separation to achieve the higher grade of polymer. Taking the plastic recovered from fridges as an example, it enters the first stage of density separation which removes the metal rich content. The second stage then separates the PVC rich material. The final stage is then responsible for separating a Polyethylene / Polypropylene mix from the Styrene polymers which form, by far, the largest volume. All the streams then go through a drying process before being bagged as final marketable products.
The fully automated plant is capable of upgrading, at least, 7,000 tonnes a year of plastic from fridges and WEEE though Sims believes it is expandable when demand increases.
Dr Hooper is already working on the next level of plastics upgrading. “We are currently continuing research related to plastics recovery and upgrading. Specific to WEEE, we are investigating the next level of technology which will allow us to further refine the styrene stream, including the separation of flame retardant polymers.”