Salzgitter AG has launched the joint project KLASSE to recover strategically important metals from steelworks slag. The project aims to extract critical raw materials such as vanadium, chromium and molybdenum from slag produced during steel production and thus reduce import dependence. The development is relevant for the construction industry, as steelworks slag has so far been primarily used as recycled aggregate in road construction or as an additive in cements according to DIN EN 197-1. Economic metal recovery could influence the availability of these secondary raw materials and open up new utilization pathways that run parallel to material use in construction.