Aluminium recycling has long been hailed as a cornerstone of the circular economy. The material’s ability to be reused has positioned it as a vital resource in reducing industrial emissions. However, as with many promising solutions, challenges persist. Chief among these is the issue of impurity tolerance in aluminium alloys, which has historically led to significant limitations in the use of recycled material. The RecAL project, a Horizon Europe initiative, aims to change this, revolutionising the way we think about secondary aluminium and its potential applications.
The RecAL project brings together 19 partners from 11 countries, including leading research institutions, industrial players, and technology providers. This diverse consortium pools expertise from across Europe to tackle the pressing challenges in aluminium recycling. Representing countries such as Austria, Germany, the Netherlands, and Sweden, the partners ensure a comprehensive approach to addressing issues across the aluminium value chain.
The problem lies in the chemistry of aluminium alloys. To achieve the strength, durability, and other properties required for different applications, aluminium is mixed with other metals such as magnesium, silicon, copper, and zinc. These alloying elements make the material versatile, but once introduced, they are incredibly difficult—if not impossible—to remove completely during recycling. As a result, when aluminium scrap is melted down, it often contains a mixture of alloys with varying levels of impurities. This creates a recycling bottleneck, as high-performance applications—particularly those in the construction, automotive, and aerospace sectors—require extremely pure inputs.
Historically, the solution has been downcycling. Impure aluminium has been directed towards lower-grade applications, such as cast alloys for combustion engines, where higher impurity levels are more tolerable. However, this approach is no longer sustainable. The shift to electric vehicles, which rely on lightweight structural components rather than heavy combustion engine blocks, means that the demand for these cast alloys is declining rapidly. By 2030, it is predicted that Europe could face six million tonnes of surplus aluminium scrap that cannot be reused with current technologies. Without significant advancements, this figure could triple by 2050, resulting in not only wasted material but also the unnecessary emissions associated with producing primary aluminium to meet demand.
RecAL aims to address this by fundamentally rethinking alloy design and production processes. Central to this is the development of next-generation alloys with significantly increased impurity tolerance. By engineering materials that can accommodate higher levels of elements like iron, copper, and silicon without compromising performance, the project seeks to unlock the potential of recycled aluminium for high-impact applications.
One of the most ambitious targets of the project is the transformation of the widely used 6xxx series alloys, which dominate the construction and automotive sectors. These alloys, typically made from virgin aluminium, have low impurity thresholds, making them difficult to produce from recycled scrap. RecAL is working to widen the composition range of these alloys, allowing for a much greater proportion of secondary aluminium to be used. Early tests suggest that impurity tolerance in these alloys could be increased by a factor of 1.5 to 2, enabling up to 75% recycled content. This would mark a fivefold increase in the impurity tolerance of construction alloys, a game-changer for sustainability in the sector.
The project is also tackling the challenge of recycling aerospace-grade aluminium, which has historically been one of the most difficult materials to reuse. High-performance 7xxx-series alloys, used in both aerospace and automotive crash management systems, are particularly sensitive to impurities. By developing microalloying strategies that enhance the material’s ability to tolerate elements like silicon, manganese, and iron, RecAL aims to create a viable recycling pathway for these valuable materials. The goal is to achieve a blend of aerospace scrap and other recycled inputs that meets the stringent requirements of these demanding applications.
In addition to traditional wrought alloys, RecAL is exploring innovative solutions for additive manufacturing (AM). The flexibility of AM processes offers new opportunities to utilise recycled aluminium in complex, high-performance parts. RecAL is developing an advanced AM-compatible alloy that incorporates up to 80% recycled content from aerospace scrap, maintaining excellent mechanical properties such as yield strength, ductility, and corrosion resistance. This represents a significant step forward in integrating recycled aluminium into cutting-edge manufacturing techniques.
The project doesn’t stop at alloy design. To ensure that these innovations are practical and scalable, RecAL is also focusing on improving sorting, refining, and production processes. Enhanced sorting technologies, including robotics and artificial intelligence, are being developed to create purer recyclate streams. These systems will enable better separation of alloy types at the source, reducing the need for energy-intensive refining later in the process. For the refining stage, RecAL is optimising the use of salt fluxes to remove impurities more effectively during melting, further improving the quality of recycled aluminium.
All of these advancements are underpinned by the creation of a digital platform, the RecAL Circularity Hub. This interactive tool will serve as a centralised resource for tracking aluminium flows, matching supply with demand, and enabling better collaboration across the value chain. By integrating real-time data and predictive analytics, the platform will help industry stakeholders maximise the use of secondary aluminium while minimising waste and environmental impact.
The potential impact of RecAL’s work cannot be overstated. By redefining impurity tolerance in aluminium alloys, the project aims to eliminate the need for downcycling and unlock the full potential of recycled materials. This could save millions of tonnes of aluminium scrap from going to waste, reducing reliance on energy-intensive primary production and cutting greenhouse gas emissions in the process. For industries like construction, automotive, and aerospace, it offers a pathway to meet sustainability targets without compromising on performance or quality.
As Europe moves towards its goal of a circular economy, projects like RecAL are leading the way. By combining cutting-edge alloy design, advanced processing techniques, and digital innovation, the project is demonstrating that the challenges of aluminium recycling are not insurmountable. Instead, they represent an opportunity to transform the industry and create a more sustainable future for all.