Sims' Europe-wide WEEE service is currently processing over 75,000 tonnes of WEEE through dedicated equipment across its European operations, while its UK fridge plant is recycling over 700,000 units annually. Their material recovery process utilise a mixture of hand dismantling and mechanical plant to recover materials.
The hand dismantling is concentrated on monitors and televisions, stripping out the cathode ray tubes from the monitor body and electrical components. The hand stripping results in around 1,500 tonnes of high grade plastics with sustainable markets.
The mechanical processes use size reduction to separate metallic and non-metallic materials. Eventually these processes produce a mixed plastic stream containing contaminants; 15,000 tonnes of product with limited markets for sale. The new plant will also include batch processing to ensure brominated flame retardants are processed separately. It then cleans the plastic of contaminants before producing three major product streams.
The first product stream is a polyvinylchloride (PVC) rich product and accounts for approximately 5% of production. The second stream is a polypropylene/polyethylene (PP/PE) mix which also accounts for 5% of production. The final stream is a styrene mixture containing a mix of high-impact polystyrene (HIPS) and acrylonitrile butadiene styrene (ABS) depending on the source of the plastic material.
Materials technologist Dr Richard Hooper has been in charge of developing the process: "It was critical for Sims Group to develop this plastics recycling plant due to the tonnages that are arising from our operations across Europe," he says. "We have now achieved a number of highly sustainable markets for our plastic products that help us achieve the best possible value for materials recovered from WEEE, allowing us to offer customers competitive prices for processing materials.
"Just as important is the positive effect on our recycling and recovery rates. We are still refining the plant, but our calculations suggest that less than 2% of plastic from our incoming WEEE will be destined for landfill."
With 90% of plant production being a mixed stream of styrene plastics, Sims' efforts are now concentrated on upgrading this into individual polymer streams. Dr Hooper continues: "We have cracked the technology for the method of separating HIPS from ABS and are currently working on industrialising the process to cope with the quantities involved. If the process proves commercially viable we should be seeing it in action later this year."