Upcycling aluminium scrap into usable alloys

Max Planck researcher Dheeraj Kumar Saini receives Early Career Researcher Award

At a glance:

• Award: Dheeraj Kumar Saini wins Early Career Researcher Award for outstanding contributions to aluminium science and technology, given by the International Conference on Aluminium Alloys 2026
• Research focus: Converting mixed aluminium scrap into commercially usable alloys
• Challenge: Removing unwanted alloying elements from complex aluminium scrap streams
• Approach: Combining thermodynamic modelling, controlled solidification and filtration to separate impurities

How can mixed aluminium scrap be transformed into high-quality industrial materials instead of being downcycled or discarded? 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. His work has now been recognised with an Early Career Researcher Award by the International Conference on Aluminium Alloys 2026.

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 awardees, Saini will present his research in a plenary talk during the International Conference on Aluminium Alloys taking place from 13 – 17 September 2026 in Berlin, Germany.

Why aluminium recycling matters

Aluminium is one of the most recyclable engineering materials: around 75% of all aluminium ever produced remains in use today. Yet producing primary aluminium from raw materials is highly energy and carbon intensive.

Recycling aluminium scrap offers a much more sustainable alternative. Secondary aluminium production requires only a fraction of the energy used for primary production and significantly lowers 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 becomes much 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 common 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 aluminium alloys widely used in automotive and die-casting applications, particularly the iron and manganese content exceeds the needed level. To turn this mixed waste into commercially viable aluminium alloys, these elements must be reduced below impurity tolerance limits.

Removing impurities through smart processing

Saini’s idea to solve this challenge is to selectively form iron-rich solid particles known as intermetallic phases, inside molten aluminium and remove them before the material solidifies into a final alloy. By carefully controlling temperature and processing conditions, unwanted phases can be separated from the melt.

Thermodynamic modelling helped identify 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 a pathway for upcycling mixed aluminium scrap into commercially useful alloys rather than lower-value recycled material.

This is particularly relevant for the automotive sector, both a major source of aluminium scrap and a major consumer of aluminium casting alloys. Developing scalable methods to recover valuable materials from mixed waste streams could help reduce emissions, lower energy consumption and support a more circular aluminium economy.