Researchers at TU Bergakademie Freiberg and the Karlsruhe Institute of Technology (KIT) are investigating the use of used carbon fibres as a reducing agent in the processing of metallurgical slags into valuable metals. The used fibres could replace conventional carbon-based reducing agents.

Whole or pulverised carbon fibres are mixed at very high temperatures into a molten slag, which is a residue from the smelting of metals. The carbon from the fibres reacts with the iron oxide in the slag to form pig iron, which can then be reused in steel production.

The method of reductively extracting valuable metals from metallurgical slags or ore concentrates is already established in research and development. However, carbon from coal or coke has been used to date. Spent carbon fibres could replace these fossil raw materials in the future and carbon fibre plastics could also score points in recycling.

Next, the team will investigate whether the material recycling route for carbon fibres developed in the laboratory also works on a pre-industrial scale.