The production of metals generates large quantities of slag, a waste stream that often still contains considerable quantities of valuable and strategically important metals. For example, every 3 metric tonnes of steel produces one tonne of steel slag, which could contain up to 3% chromium. The percentage of chromium in ferrochromium slag may be even higher than that – up to around 10%. At present, slag is mainly being used as aggregate (gravel) in concrete or asphalt, or in unbound form as a foundation for roads, because of its excellent technical properties. 

Valuable metals from industrial waste 

VITO is working together with ten partners from five countries in the EU’s Horizon 2020 project CHROMIC, which is developing technologies for extracting these valuable metals from industrial waste substances such as steel slag.
CHROMIC is seeking a radically new approach to metal recovery in which as many of the metals as possible are (selectively) recovered, so that the remaining residual material can also be put to good use in the construction industry. This ensures that no new waste streams are created. The CHROMIC process cleverly integrates new and existing technologies in a sequence of different stages (innovative pre-treatment, selective alkaline leaching, and selective metal recovery). 

Economically and ecologically sustainable

While the process is under development, the cost price and environmental impact (LCA) are also checked regularly in order to guarantee that the proposed technologies are economically and ecologically sustainable. 
CHROMIC also wants to involve citizens in this project, and focus groups have been organised in which we assess what the key concerns are among experts but also among the public. By paying close attention to public opinion, we can assess what their questions and concerns are. This is also important when a project is being implemented on a large scale.


CHROMIC is a research and innovation project funded by the European Commission within the Horizon 2020 programme. It was launched in November 2016 and runs until October 2020 (Grant Agreement Number 730471).