Valorization of electric arc furnace primary steelmaking slags for cement applications

• Using 30Al-dross total Fe content in EAF slags were reduced from 21% to 15%.
• FeO below 5 wt% obtained using a stirred carbon rod to produce cement clinkers.
• REAFS mixed with cement was found to be comparable to commercialized GGBFS.
• CCT and TTT indicated EAF slags more likely crystallized with higher FeO.

To produce supplementary cementitious materials from electric arc furnace (EAF) slags, FeO was reduced using a two-stage reduction process that included an Al-dross reduction reaction followed by direct carbon reduction. A decrease in FeO was observed on tapping after the first-stage reduction, and further reduction with a stirred carbon rod in the second-stage reduction resulted in final FeO content below 5 wt%, which is compatible with cement clinker applications. The reduced electric arc furnace slags (REAFS) mixed with cement at a unit ratio exhibited physical properties comparable to those of commercialized ground granulated blast furnace slags (GGBFS). Confocal laser scanning microscopy (CLSM) was used to obtain fundamental information on the cooling characteristics and conditions required to obtain amorphous REAFS. REAFS can be applied in cement mixtures to achieve the hydraulic properties needed for commercial use.