How can artificial intelligence-based sorting solutions support the realisation of circular economy and closed loop recycling of scrap tyres : A case study at Ragn-Sells

Abstract: Tyre rubber is a lightweight, elastic, shock- and noise absorbing, UV resistant, insulating material with high tensile strength that perform well in a broad range of temperatures. These are all valuable qualities that point to the benefit of recycling and reusing the material in high quality products and applications for as long as possible. Technological progress and development of products often leads to high tech solutions, aiming for optimised comfort and safety. Unfortunately, this might complicate the recycling and possible end-oflife applications for new products. For instance, the European Tyre & Rubber Manufacturers Association (ETRMA) has raised awareness to recyclers and granulators that self-sealant liquids obstruct recycling and lead to heat build-up and potential fire hazards. Tyre manufacturers therefore recommend that sealant tyres are collected separately and sent to energy recovery, how and by whom is not yet decided. This master thesis provides an overview of the changes demanded in the waste management of tyres to increase the reusability and which barriers that most frequently derail or slow it down. The research is built on circular economy strategies that aims for closed loop tyre recycling and evaluate to which extend this can be obtained when using artificial intelligence and image recognition to sort scrap tyres in the recycling facilities. The sorted tyres enable an end-of-life application that is specially design for varying tyre qualities. The reusability of post-consumer tyres can increase if combining material knowledge with pre-sorting of tyres to suit niched applications. The more material knowledge, the higher the quality of the reclaimed rubber and the modified, upgraded and refined materials can be recycled in high quality applications, optimal as feedstock in the production of new tyres. It can appear hard to use image recognition to distinguishing small labels on scrap tyres, nevertheless, sorting results provided when identifying the 3PMSF label showed high prediction rates, 87.3% of the existing 3PMSF labels was identified and only 1.6% predictions were false. Regardless of the sorting possibilities, material recycling of rubber is hard, especially when aiming for high quality products. The most promoted treatment is devulcanisation, having the highest possibility of recirculating scrap tyre rubber in the production of new. The main barrier is the three-dimensional crosslink structure in the rubber that is hard to break without damaging the polymers in the devulcanisation process. There are many new trends and technologies within scrap tyre recycling. Jointly, the efficiencies need to be higher. Other obstacles to overcome include; political constraints, the negative reputation that tyre rubber is a hazardous material, high costs pricing in relation to virgin feedstock materials and end-of-life application that can handle the huge amount of scrap tyres being discharged yearly. Massimo Cialone, product developer at Hankook Tyres captured the lack of regulations and political ventures when he at this springs Future Tyre Conference said, “We need legislation!”. The car industry is going towards a new era, autonomous cars are expected in the near future and regulatory requirements are forcing mobility towards electric vehicles. Moreover, congestion in cities and mobility needs are pushing a shift towards shared mobility. With so many unknown trends it is not yet possible to forecast the future of tyre development, neither to predict which new materials that might aggravate the recycling of scrap tyres in the future. Therefore, the advantages of an autonomous sorting platform that can be updated whenever new tyres and sorting approaches are identified is a great investing for Ragn-Sells.