Tyre Recycling: How Valuable Resources Can Be Kept in the Loop

Mechanical Recycling

Mechanical recycling of waste tyres involves shredding and pulverisation. During shredding, waste tyres are mechanically broken down into several steps, resulting in different granulate sizes that can be further processed depending on the application. The granulate is often used in asphalt mixtures, flooring, or sports surfaces. Another step in mechanical recycling is pulverisation, where rubber powder is produced, which can be used to manufacture new rubber products or as an additive in various industries.

The advantage of mechanical recycling lies in the direct reuse of the material without chemical alteration, resulting in lower energy consumption and reduced environmental impact.

Chemical Recycling

Chemical recycling of waste tyres primarily involves devulcanisation. Devulcanisation is a chemical process that breaks the sulphur bonds in vulcanised rubber, making the rubber soft and malleable again and allowing it to be used to produce new rubber products. Recycled rubber from devulcanisation can be used in tyre production, for rubber mats, seals, or other products.

The advantage of chemical recycling lies in the ability to alter the material at a molecular level, allowing the creation of new products with specific properties. Additionally, devulcanisation reduces the need for new raw materials and lowers environmental impact.

Thermal Recycling

Thermal recycling includes processes such as pyrolysis and combustion in cement plants. In pyrolysis, waste tyres are heated in the absence of oxygen, breaking them down into their components: pyrolysis oil, pyrolysis gas, carbon black, and steel wire. Pyrolysis oil can serve as a substitute for fossil fuels, pyrolysis gas can be used as an energy source, carbon black can be used as a filler in tyre production or other applications, and steel wire can be recycled. Pyrolysis allows for the recovery of valuable raw materials and helps reduce the use of fossil fuels.

Another thermal process is combustion in cement plants, where waste tyres are used as a substitute fuel. The high calorific value of tyres contributes to the energy supply of the cement production process, while the mineral components are used as raw materials in the cement product. This process reduces the need for fossil fuels and efficiently utilises the energy properties of waste tyres.

These various methods of tyre recycling help conserve resources, reduce environmental burden, and return valuable materials to the production cycle.

Recycled materials from waste tyres find diverse applications, which are both ecologically and economically significant. Rubber granulate is used in asphalt mixtures to improve the flexibility and durability of road surfaces and is found in soundproofing panels to reduce noise pollution. On sports and playgrounds, it provides a shock-absorbing layer that minimises the risk of injury, while running tracks in sports facilities benefit from the elastic and durable properties. In industrial environments and gyms, robust, non-slip flooring made from recycled rubber is used. Moreover, recycled rubber is used in many everyday products such as floor mats, shoe soles, and seals.

Upcycling or creative reuse of waste tyres ranges from construction and decorative materials to playground equipment and garden furniture. Such innovative applications help reduce waste and raise awareness about recycling.

In retreading, the worn tread of a tyre is removed and replaced with a new rubber layer, significantly extending the tyre's lifespan. This sustainable method is particularly common in the commercial vehicle industry.

Artificial intelligence (AI) can provide significant advantages in various areas of tyre retreading, improving the efficiency and quality of processes. Here are some specific applications:

Problem: Inspecting waste tyres to determine their suitability for retreading is a labour-intensive and time-consuming process that has traditionally been carried out manually.

How AI Can Help: AI-powered image processing systems can automatically inspect tyres for damage and wear. These systems use machine learning to detect patterns and anomalies that indicate defects. This increases the accuracy and speed of inspection and reduces human error.

Problem: The amount of material used in retreading must be carefully calculated to conserve resources and minimise costs.

How AI Can Help: AI algorithms can calculate the optimal amount of new rubber required for tyre retreading. They consider the specific characteristics of each tyre, thus minimising material consumption and waste.

Problem: Production processes in retreading are complex and require precise control to ensure high quality.

How AI Can Help: AI can be integrated into production facilities to monitor and adjust processes in real-time. This includes controlling temperature and pressure conditions during vulcanisation and adjusting production parameters based on continuous data analysis. This improves the consistency and quality of retreaded tyres.

Problem: Unplanned machine downtime can lead to significant production delays and costs.

How AI Can Help: Using AI for predictive maintenance, potential machine problems can be detected early. Sensors collect data on the condition of the machines, and AI models analyse this data to predict maintenance needs before failures occur.

Problem: Manual quality control can be inconsistent and time-consuming.

How AI Can Help: AI-powered quality control systems can inspect retreaded tyres for various quality criteria, such as the uniformity of the new tread and structural integrity. These systems offer higher precision and consistency than manual inspections.

Integrating artificial intelligence into tyre retreading offers numerous opportunities to increase efficiency, reduce costs, and improve product quality. This not only contributes to the economic viability of retreading processes but also supports sustainability goals through more efficient use of resources and waste reduction.

Tyre recycling faces significant regulatory challenges that affect the efficiency and implementation of recycling processes. A central issue is the contradictory EU regulations, particularly regarding sustainable public procurement. The EU Taxonomy Regulation, which aims to promote environmentally sustainable economic activities, often excludes retreaded tyres due to their lack of inclusion in the tyre labelling regulation. This leads to retreaded tyres not being considered in many public tenders, even though they are comparable to new tyres in terms of environmental and safety properties.

Another problem is the lack of a tyre label for retreaded tyres, which would allow their integration into EU regulations. The European Retreading Association BIPAVER and the Alliance for the Future of Tyres (AZuR) have been advocating for years for the inclusion of retreaded truck and bus tyres (C3 tyres) in the tyre labelling regulation. Until this is achieved, the planning security for companies in the retreading industry remains low, hindering investments and developments.

The current regulatory situation not only burdens the economic viability of retreading companies but also contradicts the EU's climate goals. Retreaded tyres offer significant ecological advantages over new tyres, including a reduction in CO₂ emissions by over 60% and a saving of around two-thirds of the required raw materials, primarily rubber. These advantages could be better utilised through improved regulatory support and adaptation of existing regulations.

Overall, it is clear that clear and consistent regulations are necessary to fully exploit the potential of tyre recycling and to contribute to European environmental and climate goals.

Problem: Currently, retreaded tyres are not included in the EU tyre labelling regulation, which complicates their use in public tenders and their acceptance in the market.

Suggested Solution: The EU should expand the tyre labelling regulation to include retreaded tyres. This would allow retreaded tyres to receive an official label that confirms their quality and performance and promotes their use.

Problem: The current EU taxonomy regulation often excludes retreaded tyres due to their classification, even though they are more sustainable than new tyres.

Suggested Solution: The EU should amend the taxonomy regulation to recognise retreaded tyres as environmentally sustainable products. This could be achieved by adjusting the criteria for tyre classification to consider the CO₂ savings and resource conservation provided by retreading.

Problem: Contradictory regulations and a lack of clear criteria often lead to retreaded tyres not being considered in public procurement.

Suggested Solution: The EU should establish clear and uniform criteria for sustainable public procurement that promote the use of retreaded tyres. This could involve introducing specific requirements for the use of retreaded tyres in public tenders.

Problem: A lack of transparency and trust in the quality of recycling processes hinders the acceptance of recycled materials.

Suggested Solution: The introduction of a quality label for recycling companies that certifies proper and environmentally friendly recycling practices could strengthen trust in recycled products and increase their market acceptance.

Problem: Technical challenges such as material separation and the improvement of material properties require continuous innovation.

Suggested Solution: The EU and national governments should increase investment in research and development to promote technological advances in tyre recycling. This could be achieved through targeted funding programmes and partnerships between industry, research institutions, and regulatory authorities.

Best Practices

There are numerous innovative projects and best practices in the field of tyre recycling that demonstrate how companies and research institutions are working together on sustainable solutions.

Covestro: Closing the Loop for the Automotive Industry

One example of the innovative use of recycled tyres is the joint project by Neste, Borealis, and Covestro. These companies are working together to close the loop for the automotive industry by processing waste tyres into new car parts. Covestro uses recycled raw materials from waste tyres to produce high-quality polymers used in the automotive industry.

LANXESS: Sustainable Tyre Production with Rubber Additives

Another example of sustainable innovations in tyre production comes from LANXESS. The company develops and produces rubber additives that help reduce the environmental impact of tyre manufacturing. These additives improve the properties of rubber and enable more efficient production. This not only extends the lifespan of tyres but also reduces energy consumption and CO₂ emissions during the production process. This project highlights the importance of chemical innovations for sustainability in the tyre industry.

These examples illustrate how significant progress in tyre recycling and sustainable tyre production can be achieved through cooperation and technological innovations. Such projects set benchmarks and show how ecological and economic goals can be harmonised.

Tyre recycling plays a crucial role in the future of our environment and economy. Given the billions of waste tyres generated worldwide each year, it is essential to develop efficient and sustainable methods for reusing and processing these waste products. By recycling tyres, significant amounts of resources can be saved, and environmental impact reduced.

Mechanical, thermal, and chemical recycling offer a variety of ways to recover valuable materials and use them in new products. Additionally, the use of artificial intelligence in tyre recycling opens new horizons. Automated inspection systems, optimised material usage, and predictive maintenance contribute to improving the efficiency and quality of recycling processes.

Regulatory challenges, however, require continuous efforts and adjustments. Better integration of retreaded tyres into EU regulations and the creation of clear and uniform criteria for public procurement are necessary to fully exploit the potential of tyre recycling.

Overall, tyre recycling is not only a key to reducing environmental pollution but also an important factor in promoting a sustainable circular economy. It helps conserve natural resources, reduces CO₂ emissions, and offers economic benefits by creating new business opportunities and jobs. Therefore, the importance of tyre recycling will continue to grow in the future, making a significant contribution to a more sustainable world.

Exhibitors & products around recycling

• Recycling plants
• Separating and sorting systems for waste
• Size reduction equipment (crushers, shredders, grinders)
• Compounding lines
• Recyclates

Elena Blume (Editorial team K-Mag)