Background Each year, over a billion tyres are produced worldwide, requiring approximately 10 million tons of rubber material, including most of the 6.8 million tons of natural rubber produced. About a third of the total amount of used tyres end up in landfills when their useful life is over. Large volumes of tyres lying in landfills can cause fires that are virtually impossible to put out. One tyre can burn for as long as one year. Not surprisingly, the European Union outlawed the use of whole scrap tyres in landfills in 2003 and banned shredded tyres in 2006. Many initiatives have focused on finding new ways to make use of used tyres, as fuel at cement and power plants and as additives in asphalt, sport surfaces etc. It is estimated that between 10 to 20 percent of used tyres are milled to produce rubber powder. This can be added to asphalt and used as a surface covering, but it has an unpleasant smell and limited adhesive qualities because of oil residues. Objectives The project set out to demonstrate a more environmentally friendly method for the conversion of scrap tyre powder into a high quality raw material. It would show that the new product could be used effectively in plastics, coatings, resins, water-proofing, paving and other products and applications. The design for a full-scale rubber powder treatment plant was also to be prepared, thus setting the basis for a full-scale process for disposing of scrap tyres. Results Through this project, a technology for improved, odourless and fireproof rubber powder has been developed and demonstrated. Rubber powder/granules from scrap tyres were modified using dense phase CO2 cleaning techniques to extract oil and other residue. The dissolved residue was separated from the CO2 and the CO2 was recompressed and reused. With this new technology, the substances causing the rubbery smell were successfully removed from the rubber granulate on a scale of several hundred kilos. The following activities were successfully implemented: - installation of prototype plant unit for automated control of extraction and impregnation processes of SuperRubber; - verification of the laboratory results in a larger scale prototype unit; - to validate the developed technology, proof of concept tests (odourless, grass fragrance and fire retardant) were done; - at least one ton of SuperRubber was produced; - technology have been widely disseminated; - feasibility study including engineering report and economic estimate report of full scale plant was prepared. During the project, the beneficiary received requests from three organizations who were interested in constructing objects with SuperRubber as infill: Tarkett and Saltex, both producers of artificial turf and the city of Basel in Switzerland. Furthermore the municipality of Brøndby in Denmark and the Danish 1st league football club Brøndby IF, who were constructing a new training facility with artificial turf, also expressed their interest in the product. However, despite the considerable interest from potential end users, the production of SuperRubber on a larger scale is currently problematic due to the very costly cleaning of the production plant. A feasibility study for an odourless product has shown that the production cost in a 20,000 ton/year plant would be approx. 0.23 EUR/kg; this is quite high when compared to a raw material cost of approx. 0.2 EUR/kg for rubber granulate. Furthermore, at lower annual capacities the production cost is expected to be significantly higher; a market study found that many granulators produce less than 20,000 ton/year. This is therefore a further limitation for the dissemination of the technology.