Criosinter

Today, only 24% of all scrap tyres are recycled in the European Union, whilst 27% are used as fuel. The latter disposal route is expected to decrease due to more strict regulations on pollutant emissions. Consequently around 250,000,000 extra used tyres are being accumulated each year in the countries of EU. This situation is clearly of great concern, & represents a serious environmental & industrial problem.

Nearly 70% of all rubber reclaimed from tyres is used for artificial turf infill, which is a low-value application. Recent attempts to identify new ways of using recycled rubber have concentrated on high-volume uses with non-critical physical properties. Hence, there is a clear requirement for new markets for recycled rubber that offer a higher profit margin.

At the same time, manufacturers of all rubber products are greatly interested in reducing their dependence on virgin rubber, due to ever increasing raw material costs & instability in the supply chain.

However, until now, efforts to substitute virgin rubber by recycled rubber crumb have largely been unsuccessful. This is mainly due to the mechanical properties achieved when large volumes of recycled rubber are compounded with virgin rubber. Also there is a general perception in the marketplace that recycled products are inferior.

Therefore the main goal of the Criosinter project was to develop an innovative recycling process for producing recycled raw rubber with enough quality to compete with virgin rubber in highly demanding products. This was achieved by integrating emerging tyre grinding technologies, novel transformation processes & new materials design technologies. 'Emotional' engineering techniques were also used to improve the public's perception of recycled products.

The overall goals of the project were:

• Optimisation of cryogenic & water-jet grinding technologies to develop a grain morphology control system for use in rubber crumb production.
• Development of procedures for optimising high-pressure & high-temperature rubber crumb sintering.
• Development of a material design methodology that would allow the translation of product requirements into product properties.
• Identification of the emotional/perceptional barriers associated with the use of recycled products.
• Integration of the knowledge gained during the project into a process for producing high added value products from scrap tyres.

Project Website: www.criostiner-project.net

Start date: 15/10/2005 Completion date: 14/12/2007