Tyres & Rubber
After many twists and turns over the last few years, and following the latest round of consultations and discussions, the European Chemicals Agency (ECHA) has decided to recommend a ban on the use of crumb rubber infill in artificial sports surfaces. This is a massive market for the recycling sector: in Europe, for example, 62% of end-of-life tyres (ELTs) are destined for material recovery, with 527,000 tons processed to make infill for use in sports pitches.
Countless scientific studies over many years have concluded that crumb rubber infill presents no risks to health. However, ECHA’s Committee for Risk Assessment argued that information on the effectiveness of risk management measures was incomplete and that a ban would be more effective in preventing releases to the environment in the long term. During the BIR Tyres & Rubber Committee webinar in June last year, guest speaker Fazilet Cinaralp of the European Tyre and Rubber Manufacturers’ Association (ETRMA) warned that the repercussions of such a ban could well prove “catastrophic” for the crumb rubber sector and for tyre recycling in general.
The ban would be scheduled to take effect after a transition period of six years, leaving very little time for producers to find new outlets for their crumb rubber. At present, there are no material recycling alternatives for the potentially huge surplus of ELT-derived rubber infill materials, with energy recovery the only possible outlet that could attempt to absorb such large volumes. Indeed, the recommendation from ECHA is likely to provide a boost to tyre-derived fuel and pyrolysis operations, with the major oversupply of material almost certainly leading to a substantial increase in gate fees.
Against this backdrop, and with seemingly perfect timing, our Committee’s webinar in October 2020 brought first-hand confirmation that the world’s largest tyre manufacturer – Michelin – was spearheading the breakthrough BlackCycle project aimed at recycling almost 50% of Europe’s ELTs into new tyres within five or six years. Research Programme Manager Michaël Cogne explained that the initiative was pooling the talents of seven industrial partners, five research and technological organizations, and an innovation cluster, with their specialisms spanning tyre collection, granulation, pyrolysis, transformation of pyrolytic oil into more valuable materials, carbon black manufacture, life-cycle analysis, environmental assessment along the value chain, data management and communications.
The magnitude of the BlackCycle initiative and its potential as a game-changer for the used tyre market cannot be overstated. Among all industrial sectors, it is the only project of this scale designed to complete the virtuous circle when recycling end-of-life products. If BlackCycle is successful in meeting its objectives, crumb rubber manufacturers will have a substantial and reliable alternative outlet for their product; in all likelihood, they would become suppliers of feedstock either to Michelin or to similar projects which other tyre manufacturers may have in the pipeline.
Industry-led innovation is not the only route to creating a more sustainable tyre sector; policy-makers and politicians can also play a major role, such as through the introduction of mandatory recycled content quotas in new rubber compounds so long as these do not entail a significant impact on product properties.
A review of developments in 2020 would be incomplete without mention of the profound impact of the COVID pandemic. With fewer cars and trucks on the road throughout the crisis, this naturally led to a decline in the number of ELTs generated and to a decrease in the volumes recycled last year. Other key effects included an undersupply of some grades, such as rubber powder, while exportation of low-value-added ELT-derived materials became less attractive owing to unprecedented freight increases.
And of course, many COVID-related challenges have carried over into 2021.
“The magnitude of the BlackCycle initiative and its potential as a game-changer for the used tyre market cannot be overstated.”
Max Craipeau
IMPORTANT FACTS
The most important use of rubber is in vehicle tyres; over 70% of all the world’s rubber ends up wrapped around the wheels of cars, bicycles and trucks. Other applications are industrial rubber goods used in, for example, construction, aircraft, footwear and gloves.
With over a billion cars and commercial vehicles already in use worldwide, end-of-life tyres (ELTs) are among the largest sources of waste today. Tyres made of approximately 80% rubber compound, steel and textiles are built to last, which in turn makes them a very challenging product to recycle.
Historically, the difficulty in recycling has led to uncontrolled or illegal scrap tyre disposal, but with the formation of national ELT management companies such as Aliapur and Signus, and also the development of new end markets for tyre-derived materials, ELTs are increasingly diverted from landfills as the tyre recycling industry continues to grow.
In 2018, over 3 million tonnes of ELTs were recovered in Europe, representing a treatment rate above 96%. Taken together, Europe, the USA and Japan have an average recovery rate of 90%.
MATERIAL RECOVERY
For both tyres and non-tyre rubber scrap, the material recovery technologies are usually the same.
Sorting: As with all other waste streams, it is important to segregate scrap according to type and to process separately to ensure the highest quality output.
Retreading: During the sorting process, tyres which still have quality casings are sent to retreaders where they are given a second life (and sometimes more) by replacing the worn tread with a new one.
Shredding: Tyres whose casings are damaged are usually sent to a shredder for size-reduction. ELT shredders are usually smaller than those used to process end-of-life vehicles but, nevertheless, they have to be extremely robust to handle such durable materials. By downsizing tyres and other rubber scraps, many recycling opportunities are opened up.
Metal separation: Rubber scrap, especially ELTs, are commonly embedded with metal and require ferrous or non-ferrous separation using magnets and/or eddy-current technologies.
Granulation: Granulators are widely used in the rubber recycling industry to further reduce the dimensions of the shredded tyres after metal separation and to produce quality rubber granules.
Pulverization: For more technical uses, rubber granules can be pulverized at ambient or cryogenic temperatures in order to produce micronized rubber powder.
APPLICATIONS
For ELTs following the material recovery route, applications are endless but rarely follow the circular economy model. This is contrary to what is happening in other waste streams such as plastics and metals.
Applications depend mostly on dimensions:
Tyres also contain significant amounts of steel wiring which can be fully recovered and used as raw material by the steelmaking sector.
ELTs following the energy recovery route are basically used as alternative fuel.
