The DFG Priority Program 2315 on Recycling Critical Elements enters its second funding period.

The five projects from Clausthal University of Technology (TU Clausthal) have convinced in the first period and will be further funded with a total of €2 million.

The increasing complexity of products and components used in the high-tech sector leads to a wide range of elements with different chemical and physical properties being used. Conventional methods of disassembly and mechanical processing of the often microscopically small components are no longer sufficient to ensure the recovery of all valuable materials. This is particularly critical for economically important raw materials that are available in small quantities. High-temperature processes can be used, but a part of the valuable materials ends up in the slag and is currently lost. A typical example is the recycling of lithium-ion batteries.

The Priority Program (SPP 2315) with the title "Engineered Artificial Minerals (EnAM) - a Geometallurgical Tool to Recycle Critical Elements from Waste Streams" started in 2021. It was initiated by Prof. Daniel Goldmann (TU Clausthal) and Prof. Dr. Urs Peuker from the TU Bergakademie Freiberg. In the first funding period, 19 individual projects were funded in the areas of slag modification and enrichment, as well as comminution and separation. All Clausthal projects have convinced and will be further funded with a total of approximately €2 million.

In the first funding period, the participating working groups have networked both internally at TU Clausthal and with other groups of the SPP. A total of 14 young scientists were funded at TU Clausthal.

Experimental methods for the creation of slag analogues and individual components were established in the projects of Dr. Thomas Schirmer (IELF), Prof. Dr. Alfred Weber, Dr.-Ing. Annett Wollmann (IMVT) and Prof. Dr. Ursula Fittschen (IAAC). These methods are used in part in the separation projects of Prof. Andreas Schmidt (IOC) and Prof. Alfred Weber & Dr.-Ing. Annett Wollmann.

Freezing phenomena and melt structure could be better understood in the collaboration of the modeling and experimentally working groups. The non-equilibrium thermodynamic model developed by Prof. Dr. Michael Fischlschweiger (IEVB) shows how crystals form dynamically in mineralogical systems during freezing and explains kinetic phenomena during phase formation. The molecular dynamics simulations (MD simulations) by Prof. Dr. Nina Merkert (IMET) have shown how the viscosity and diffusion of individual ions change with changes in the melt composition, which in turn affects the freezing in the melt. The knowledge gained from these simulations about the coordination of ions can flow into other models in the future.

From the mineralogically oriented project of Dr. Schirmer together with the University of Bochum, a new group of promising enrichment compounds (EnAM) was identified, which are lithium manganates. The influence of the oxidation stage of manganese on the component formation will be the focus in the second phase, as it has a significant impact on the enrichment of lithium. How the structure of the melt, taking into account potential phase separation, affects the redox properties will be investigated by Prof. Dr. Nina Merkert and Prof. Dr. Ursula Fittschen in cooperation with the project of Prof. Dr. Michael Fischschweiger.

In the area of separation technology, significant successes have already been achieved in the dry separation of model mixtures by tribo-electric charging and electro-sorting in the project of Prof. Alfred Weber and Dr.-Ing. Annett Wollmann. Similarly successful was the flotation separation of mixtures using novel switchable collector molecules derived from the natural product punicin, which is found in pomegranate tree leaves. These molecules were synthesized in the working group of Prof. Dr. Andreas Schmidt and tested under various conditions. The fascinating light-dependent selectivity of these compounds is particularly noteworthy.