Reuse of vitrified argon oxygen decarburization slag as supplementary cementitious materials: Comprehensive performance and chromium immobilization mechanism

Abstract

• The virified AOD slag with CaO/(SiO 2 + Al 2 O 3 ) = 0.82 has the higher [SiO 4 ] depolymerization and reactive silicate network. • The vitrified AOD slag based cementitious material reaches to 52.5R strength level of Portland cement. • Higher polymerization degree of glass owning stronger chromium immobilization ability. • Chromium can be physical encapsulated in cementitious material with denser microstructure and higher hydration degree. Using vitrified argon oxygen decarburization (AOD) slag as a supplementary cementitious materials (SCM) provides low carbon consumption and improved slag recycling. We investigated vitrified AOD slags with fly ash (FA) as the SCM. The results show that the vitrified AOD slag with CaO/(SiO 2 + Al 2 O 3 ) = 0.82 has the highest [SiO 4 ] depolymerization. The cementitious materials (CM) dosage with this slag reaches the 52.5R strength level of Portland cement. The chromium can be physically encapsulated in CM with denser microstructures and higher hydration degrees. The amount of chromium leaching from the vitrified AOD slag and CM meet the industrial requirements. Thus, vitrified AOD slag is a promising SCM.