In our ongoing effort to develop sustainable extraction processes, process metallurgy team at HIF successfully conducted a pilot-scale vanadium recovery campaign using our in-house 100 L leaching reactor. The process targeted LD slag, a steelmaking by-product rich in valuable elements.

Over the course of the campaign, we processed 30 kg of LD slag in three batch operations. Each batch involved leaching 10 kg of slag with 80 liters of lexiviants in optimized conditions. The leaching process yielded pregnant leach solution (PLS) containing approximately 2 g/L of vanadium, achieving an impressive vanadium extraction efficiency of nearly 80%. This confirms the effectiveness of our process on one of the largest demonstration scales in the EU at the moment. This solution feed will be used to recover V in next steps.

As a secondary outcome, each batch also produced 10 kg of gypsum (CaSO₄2H₂O) as a by-product. This gypsum was thermally treated to convert it into hemihydrate (CaSO₄·0.5H₂O), reducing the overall mass to approximately 26 kg due to water loss—an important step toward value-added utilization in construction application.

Picture: From left to right: Large-scale leaching of LD slag on a 100-liter scale; automated filtration of the valuable (V) water; decontaminated residue for construction applications.

In this way, the LiDoVa research team demonstrated a circular economy process for battery metals (V) and sustainable construction materials i.e. gypsum in decontaminated form. The recomine-partners Nickelhütte Aue GmbH and the Chemnitz University of Technology (TUC) are supporting these developments in a joint project. You can find out more about the recomine project LiDioVa here.

Future Outlook:

Simultaneously, our team (HIF) is initiating in-house research on vanadium-selective recovery from the PLS. The upcoming phase will employ solvent extraction using a mixer-settler system to isolate and purify vanadium, targeting the production of high-grade vanadium concentrate solutions suitable for advanced applications.

Looking ahead, our project partner (TUC) are actively exploring the use of the hemihydrate gypsum in the development of alkali-activated binders, aiming to create sustainable construction materials from industrial residues.

These integrated approaches not only enhance resource recovery from waste but also align with circular economy principles and green chemistry goals.

Project duration: from 01.01.2023 to 31.12.2025