Upcycling aluminium scrap into usable alloys
With new processing strategies, complex aluminium waste could be transformed into high-quality, marketable industrial materials – instead of being downcycled or disposed of.
How can mixed aluminium scrap be converted into high-quality industrial materials, rather than being downcycled or disposed of? At the Max Planck Institute for Sustainable Materials (MPI-SusMat), postdoctoral researcher Dr Dheeraj Kumar Saini is developing processing strategies to convert complex aluminium waste into commercial alloys for industrial use. He has now been awarded an Early Career Researcher Award by the International Conference on Aluminium Alloys 2026 for his work.
The award recognises outstanding early-career researchers who have already made a significant contribution to aluminium science, technology and applications. As one of five international award winners, Saini will present his research findings in a plenary lecture during the International Conference on Aluminium Alloys, which takes place in Berlin from 13 to 17 September 2026.
Why aluminium recycling is important
Aluminium is one of the most recyclable materials: around 75 per cent of all aluminium ever produced is still in use today. However, the production of primary aluminium from raw materials is extremely energy- and CO₂-intensive.
Recycling aluminium scrap offers a significantly more sustainable alternative. Secondary aluminium production requires only a fraction of the energy used in primary production and significantly reduces greenhouse gas emissions. As global demand for aluminium continues to grow, recycled material is expected to play an increasingly important role in meeting industrial needs. However, recycling is made considerably more difficult when scrap streams contain mixed alloy compositions.
Tackling a complex recycling challenge
Saini’s research focuses on so-called ‘twitch scrap’ – shredded aluminium waste containing a mixture of cast and wrought alloys. This type of scrap is widespread in industrial recycling streams and contains a complex combination of alloying elements such as silicon, copper, zinc, magnesium, iron and manganese. Although twitch scrap resembles the aluminium alloys widely used in the automotive industry and die-casting, the iron and manganese content in particular exceeds the required limits. To convert this mixed scrap into commercially viable aluminium alloys, these elements must be reduced to below the tolerance limits for impurities.
Removal of impurities through intelligent processing
Saini’s idea for tackling this challenge is to selectively form iron-rich solid particles – known as intermetallic phases – within the aluminium melt and remove them before the material solidifies into a final alloy. By carefully controlling the temperature and processing conditions, unwanted phases can be separated from the melt. Thermodynamic modelling helped to determine when these iron-rich compounds form and how much material precipitates at different temperatures. Saini combined experimental filtration studies with calculations of melt flow, viscosity and sedimentation behaviour to optimise removal efficiency.
Towards better aluminium recycling
The approach could open up a way to utilise mixed aluminium scrap to produce commercially viable alloys rather than low-grade recycled material. This is particularly relevant for the automotive sector, which is both a major source of aluminium scrap and a significant consumer of aluminium casting alloys. The development of scalable methods for recovering valuable materials from mixed waste streams could help to reduce emissions, lower energy consumption and promote a more circular aluminium economy.
Source: MPI-SusMat