A large number of recovery and reuse channels

Because of their elasticity, resistance, calorific value, carbon content and durability, end-of-life tires can be reused in a wide variety of ways. Of the many available recycling processes, half involve energy recovery using ELTs as a fuel whose calorific value is comparable to that of good quality coal (a tonne of ELTs can replace 750 kg of oil). The use of ELTs as a fuel and their contribution to the diminution of fossil CO₂ emissions thanks to their natural rubber content coming from rubber trees is especially developed in the United States and in Japan to fire thermal power plants, industrial boilers and incinerators. They are also used both as fuel and as raw material in steel mills and cement plants.

Moreover, using ELTs as a fuel offers another benefit in that around 20% of an ELT’s mass is natural rubber, which is carbon neutral because it comes from trees that sequester CO₂. That’s why in Europe, the CO₂ released when this content is burned is exempt from emissions taxes. The other 50% of tire recycling processes involve recovering and reusing ELT resources. Whole tires are used as backfill and in noise-abatement walls, while tire fragments can be formed into railroad track crossties that reduce noise and vibration. Shredded tires are used as draining sub-layers or as light filling material in road construction. When ground into crumbs or powder, they can be used to make synthetic surfaces for sports fi elds or playgrounds. Powdered rubber is added to asphalt to make roads longer lasting and quieter, or blended into thermoplastics to produce composite materials. In-situ tests and toxicity studies conducted by independent laboratories have demonstrated that these products pose no environmental or health hazard.

Sharing best practices

End-of-life tires pose two problems: processing the more than 17 million tonnes of tires that are discarded every year and absorbing the estimated 50 million tonnes in backlog, mostly in emerging markets without any ELT recycling programs.

Michelin is participating in a World Business Council for Sustainable Development (WBCSD) working group that is identifying best practices and promoting the creation of resource recovery channels in emerging markets. In Western Europe, about fifteen management companies are sharing their experience and improvements. In 2008, the combined recovery rate in the 27-country Europe stood at 96%. In France, tire manufacturers and dealers signed an agreement with the government, pledging to eliminate all of the country’s legacy ELT stockpiles – estimated at 200,000 tonnes – by 2018.

Supporting the development of recovery routes

As raw materials grow increasingly scare and stricter environmental standards become the norm, end-of-life tires, usually seen as waste, are in fact increasingly viewed as a resource. As a result, their recovery and reuse are becoming more economically viable year by year. European regulations classify products made from ELT as non-hazardous waste, which means that their transport and processing is subject to severe, time-consuming constraints.

As a member of the European Tyre and Rubber Manufacturers’ Association (ETRMA), Michelin is supporting an initiative to have scrap tire rubber reclassified as a secondary raw material. A key step in this process was taken in October 2008 when the European Parliament and Council adopted Directive 2005/0281 on waste.

To actively promote the development of reuse and recovery channels, Michelin and the ETRMA are also working on a European standard for products made from ELTs, which would support their classification as a by-product rather than a waste. Industry-backed research partnerships are also exploring new recovery processes to increase ELTs’ value in use.

Categories: Emissions - Sustainable mobility

Keywords: green tire - Tires - Recycling