Every year, around 600,000 tonnes of used tyres accumulate in Germany and have to be disposed of. In the past, most used tyres were incinerated, but today a large proportion is recycled and reused in new products - a positive development for the environment with a lot of untapped potential.
In view of climate change and scarce natural resources, a tyre consisting of many valuable components should not be used just once. Stakeholders in the recycling industry are therefore working hard to find new solutions for the sustainable disposal of tyres in line with the Circuar Economy. This is because the disposal problem is growing: tyres must not be disposed of in landfill and more and more used tyres are being carelessly discarded in the countryside, where they cause great damage. The demand for used tyres in the cement industry is also falling sharply: cement works, which have been using used tyres as a fuel substitute since the 1970s and were the main customers for a long time, are increasingly turning to other heating materials. In terms of the environment, thermal utilisation is also not the first choice: in the EU, material recycling has priority.
Material recycling - the recycling route of the future
More sustainable are treatment and processing techniques with which the valuable components of used tyres can be returned to the material cycle and used for longer. Science and industry are therefore developing more and more recycling processes for used tyres - from retreading, granulation and fine grinding to pyrolysis and devulcanisation. Successes can already be seen: In recent years, the material recycling of used tyres has steadily increased; thermal recycling, on the other hand, is on the decline. According to the German Rubber Industry Association (wdk), the proportion of tyres recycled thermally was still over 50 per cent in 2000; in 2019, it was only 34 per cent - and the trend is downwards. Experts assume that the proportion of thermally recycled tyres will continue to fall in the future. The trend in material recycling is quite different: while the proportion of tyres recycled in 2000 was around 40 percent, in 2019 a good 68 percent were recycled in this way - and the trend is rising. Material recycling includes the processing of tyres into granulates and flours, which in turn are further processed as materials in new products. In 2019, 251,000 tonnes of granulates and rubber powder were produced from used tyres.
Used tyres are valuable raw materials
As the only connection between the vehicle and the road, tyres must be able to withstand high forces. For this reason, they are made of particularly resistant materials. Tyres contain 800 to 900 different substances. The main component is rubber, but there are also fillers such as carbon black and silica, reinforcing materials such as steel and polyester as well as chemicals such as sulphur and zinc oxide. Due to their complex composition, the recycling of tyres is complex and should be carried out by experts. In material recycling, used tyres are shredded in shredder and granulate plants and processed into rubber powder or granulate.
Tyre recyclates have many positive properties and can therefore be used flexibly. Whether as floor coverings, asphalt additives, anti-slip mats, ramps, path edgings, noise barriers, sealants or lamps and vases - the possible applications are many and varied. Products made from recycled tyres are durable and a good example of a functioning circular economy in which products are used as long and efficiently as possible - without producing new waste. The partners of the NEW LIFE initiative process used tyres into rubber powder or granulate or produce new products from these secondary raw materials. If as many used tyres as possible are recycled, resources can be conserved and the many valuable components of tyres can be put to good use.
Sources:
https://www.bundesverband-reifenhandel.de/themen/altreifen/aufkommen-verwertung/
https://azur-netzwerk.de/wp-content/uploads/Machbarkeitsstudie-Azur_25.01.2020_V1.1.pdf (S. 7)
