Characterization of EAF Steel Slag Waste: The Potential Green Resource for Ceramic Tile Production

Abstract

This study aims to characterize and investigate properties of electric arc furnace (EAF) steel slag waste to ensure its compatibility and suitability in ceramic tile production. Initially, the lump form of EAF slag obtained from Southern Steel Berhad, Penang (one of Malaysia's largest steel makers) was crushed into powder. The slag powder was then characterized in terms of loss of ignition (L.O.I.), chemical composition, leaching behaviour, phase analysis and flow button test. The EAF slag was found to have superior low L.O.I. (0.01wt.%). In terms of chemical composition, the slag mainly consisted of oxides such as Al2O3, CaO, MgO, SiO2, FeO and Fe3O4, which are similar with typical raw materials (clay, silica and feldspar) for ceramic tile production. CaO based complex oxides such as larnite (2CaO.SiO2) and gehlenite (Al2O3.2CaO.SiO2) were the major mineral phases in the slag while wustite (FeO) and magnetite (Fe3O4) were present as the minor phases. From flow button test, it was observed that the EAF slag began to fuse at 1250°C. Leaching test revealed that concentrations of the heavy metals leached from the EAF slag in both tap water and rain water conditions were lower than the limit regulated by Department of Environment (DOE) Malaysia. Thus, the slag could be considered as non-hazardous and it is safe to be utilized as one of the raw materials for ceramic tile production. Future studies will focus on body formulation and properties of the ceramic tile incorporated with the EAF steel slag waste.