Reduction of steel‐making slags for recovery of valuable metals and oxide materials

Extensive researches on slag reduction for recovery of valuable metals and oxide materials from metallurgical slags and other wastes using a DC furnace with a hollow electrode have been conducted in 2 major EU projects with close cooperation between MEFOS, FEhS and CRM. Steel slags and other residues were introduced into the reactor through the hollow electrode to the hot plasma. The materials were melted, reduced and mixed. The final products were a metal product, a slag product with targeted chemical composition and a dust fraction with a high content of ZnO. Different steel‐making slags and residues including BOF slag with low and high V‐content as well as EAF and AOD slags from stainless steel production, EAF dust, oily millscale, hydroxide sludge, BOF and BF dust have been treated. The slag products include a metallurgical powder for desulfurization of steel, hydraulic binder and slag stones for construction applications. The metals obtained are rich in Fe, Mn, V and Cr depending on the treated slag and residues. The environmental compatibility and mechanical properties of the slags have been improved after slag reduction.