The Audi Environmental Foundation (AEF) aims to extract resources sustainably, encouraging a closed-loop supply chain.

The AEF, in collaboration with the Technical University (TU) Bergakademie Freiberg, is funding innovative research into the recovery of metals such as indium, gallium, and tin from fly ash and slag produced during the incineration of household waste using selective extraction techniques. 

At present, most recycling programmes targeting electronics focus primarily on the recovery of gold, copper, and platinum group metals owing to their high economic value. However, consumer electronics also contain other metal components, such as tin, the economically feasible recovery of which would move us ever closer to a closed-loop supply chain.  

Electronic devices are often incinerated along with general waste when they are not sent to appropriate recycling facilities, and it is estimated that a significant amount of metal is contained in waste incineration ash every year. The research funded by the AEF aims to recycle this waste via the selective extraction of indium, gallium, and tin from the ash of waste incineration plants. The ash is treated with an acid to create a solution containing various metal ions. Custom-made molecules (ligands) are specifically tailored to target each metal, which is then selectively extracted from the solution. Finally, the ligands are induced, and the metal ions are released, resulting in a pure metal ion solution, which is then further processed into metal.  

Once further optimised, this process has the potential to be used in other applications, such as the recovery of metal elements from photovoltaic modules and other electronic waste (e-waste). The effective recycling of e-waste and electronic components is necessary to preserve global reserves and achieve long-term sustainable development goals.