TU Bergakademie Freiberg Recycles Metals from Electrolyzers

A new process enables rare earths to be recovered and reused from electrolysers. Practical testing for the circular economy is now pending.

Rare earths such as scandium, lanthanum, and cerium are key components of solid oxide fuel cells used for hydrogen production. Around 150 kg of these metals are contained in a 10 MW module. Until now, most of the material has ended up as scrap at the end of the cells' service life. A research team at TU Bergakademie Freiberg has now developed a method for recovering and reusing the metals used.

The team is using a hydrometallurgical process in which the metal oxides are extracted from the cell material using acids. First, the electrodes and solid electrolytes are mechanically separated from the steel, which serves as a separating layer and electrical contact. The rare earths are then selectively extracted from the electrodes. In the future, the individual elements will be separated from each other in an environmentally friendly manner and returned to the production cycle.

Larger Laboratory Scale

“The results now published were obtained on a small scale of 0.2 g of cell material per experiment, but we are already working on transferring the results to a larger laboratory scale of currently up to 50 g,” explains project team member Dr. Pit Völs. The processes developed will also be evaluated in terms of sustainability through a life cycle analysis.

The process was developed as part of the GrInHy3.0 (Green Industrial Hydrogen) project in collaboration with industry partners. The aim is to develop a new technology for hydrogen production in solid oxide electrolysis cells that also closes the material cycle. Project manager Professor Alexandros Charitos emphasizes the environmental aspect: “In the long term, this will reduce the impact of future waste streams from hydrogen production.”

Practical Testing with Partners

Practical testing will take place over the next three years at the facilities of project partners Sunfire SE and Salzgitter Flachstahl GmbH. The pilot plant is expected to produce up to 14 kg of hydrogen per hour in the future. The project is funded by the US Department of Energy until 2027.

This is a partly automated translation of this german article.