If you’ll pardon the pun, the good times are continuing to roll for tyre recycling. Indeed, for rubber recycling as a whole. As I said at our committee meeting in Barcelona last May, this has become one of the most dynamic sectors of the recycling industry, gaining unprecedented traction as a result of the ever- increasing possibilities for breathing new life into tyres and other rubber products.
A compound annual growth rate of more than 10% is projected for the global recycled rubber market in the years to 2028. In Europe alone, demand for recycled rubber is expected to increase fivefold over the next 25 years.
Of course, there are challenges encountered daily along the way. I am sure we would all wish for a trading and economic environment that was more supportive of our activities and of our profit margins. Like most other industries around the globe, we are suffering the effects of soaring energy costs and manpower shortages, as well as grappling with the ongoing issue of sourcing reasonably-priced vessel space for shipping our materials.
Specific to our sector, we are also facing severe sanctions on what was once the jewel in the crown of used tyre outlets. During 2022, the European Commission adopted a draft proposal to restrict the sale of tyre-derived infill materials smaller than 5 mm in size in a move that will effectively prevent its use in synthetic pitch surfacing once a six-year transition period has elapsed.
This blow to recycling is grounded in a European Chemicals Agency recommendation to ban all “microplastic” infills owing to possible release to the environment, even though recycling industry experts have contested the data and have championed the far more sensible option of mandatory risk-management measures to limit the dispersion of infill materials. The harsh reality of such a ban could be that more than 50 million tyres go unrecycled or are exported outside the EU for incineration where environmental standards are less stringent, according to Emmanuel Katrakis of the European Recycling Industries’ Confederation.
Thankfully, at our Barcelona meeting last May, Mr Katrakis gave us reasons for greater optimism: policy-makers in Europe had finally understood, he said, that creation of a Circular Economy was not simply a matter of recycling targets but also of creating a demand and of introducing sustainability at the design stage of a product.
Indeed, and as I pointed out at our subsequent meeting in Dubai, this increasingly deep understanding of sustainability – particularly among customers – means there has probably never been a better time to be a tyre/ rubber recycler. Not so many years ago, who could have dreamed that such tyre industry luminaries as Michelin,
Continental and Bridgestone would be striving for a massive scale-up of their use of our raw materials?
I am delighted to say that our committee meetings have earned an enviable reputation for showcasing latest research and technology developments. In Barcelona, Sonia Megert of Switzerland’s Tyre Recycling Solutions SA highlighted the massive growth potential for recycled content in tyres, suggesting that 10-15% was achievable in tyre treads compared to a current maximum of 5%.
At the same meeting, Robert Weibold of Robert Weibold GmbH in Germany also confirmed that many investors were now taking greater interest in this field, not least because the economics of recycling processes have been altered by the fact that customers are now prepared to pay significantly more for a sustainably-produced tyre.
In Dubai last October, another of the valuable services provided by our meetings was highlighted, namely the opportunity to focus on recycling developments in parts of the world that do not often come under the microscope. So it was that we heard from: Khaled Jamal Chaaroui of EPSCO Global General Trading in Kuwait who updated us on a local tyre recycling plant producing crumb, granules, powder, steel scrap and fibre waste; Abdullah Ahmed Alqurashi of Global Environmental Management Services who explained how Saudi Arabia was tackling the challenge of the 572,000 tonnes of end-of-life tyres generated domestically each year, with his own organization tasked with developing centralized collection hubs and sorting stations; and Zaid Bdour of The Gulf Rubber Company who emphasized the strong business case for mechanical recycling despite the volatility of used tyre prices owing to lucrative exports to Pakistan and India.
If the measure of a vibrant industry is its scope to promote global conversation and innovation, then tyre and rubber recycling has truly arrived.
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%.
There are several ways in which tyres can be reused or recycled. There are important differences in laws and regulations worldwide aimed at encouraging or discouraging different methods.
The two main recycling routes are material recovery and energy recovery, and their share of ELT treatment varies from country to country. For example, the split between material recycling and energy recovery in Europe is around 50/50 whereas energy recovery accounts for a higher proportion in the USA.
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.
In Europe, almost half of the tyres collected are used to replace coal in coal-fired power stations and in cement furnaces. Other industries, such as steel manufacturers, also use scrap tyres as a fuel in place of fossil fuels. When these industries choose ELTs over coal, they can limit their CO2 emissions by up to 30%. Compared to coal, ELTs are on average 80% cheaper while having 110% of its heat value.
Halfway between material and energy recovery lies tyre pyrolysis, a technique that heats whole or shredded tyres in a reactor vessel containing an oxygen-free atmosphere in order to extract fuel and other components.
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:
Shredded tyres/rubber (+/- up to 200 mm)
In civil engineering works, shredded tyres can be used as a filler to stabilize weak soil and also as insulation for roads, bridge abutments, etc.
Granulated tyres/rubber (+/- up to 20 mm)
One of the major outlets for ELTs and other rubber scrap is in granule form for artificial turf and playgrounds.
Pulverized tyres/rubber (+/- up to 2 mm)
Coarser rubber powder is used in asphalt applications to improve road performance, reduce noise levels and lower maintenance costs.
Finer rubber powder (micronized) can be incorporated at low levels as a filler in virgin rubber compounds and can be further processed into reclaimed/regenerated rubber, which is currently the only way to use ELTs and other rubber scrap in line with the circular economy model.
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.
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 ELT recovery rate of 90%.
ELTs used as fuel are on average 80% cheaper than coal while having 110% of its heat value.