Steel slag is one of the most common waste products from the steelmaking industry. Conventional methods of slag disposal can cause negative impacts on humans and the environment. In this paper, the process of steel and steel slag production, physical and chemical properties, and potential options of slag recycling were reviewed. Since steel is mainly produced through an electric arc furnace (EAF) in Malaysia, most of the recycling options reviewed in this paper focused on EAF slag and the strengths and weaknesses of each recycle option were outlined. Based on the reports from previous studies, it was found that only a portion of EAF slag is recycled into more straightforward, but lower added value applications such as aggregates for the construction industry and filter/absorber for wastewater treatments. On the other hand, higher added value recycling options for EAF slag that are more complicated such as incorporated as raw material for Portland cement and ceramic building materials remain at the laboratory testing stage. The main hurdle preventing EAF slag from being incorporated as a raw material for higher added value industrial applications is its inconsistent chemical composition. The chemical composition of EAF slag can vary based on the scrap metal used for steel production. For this, mineral separation techniques can be introduced to classify the EAF slag base on its physical and chemical compositions. We concluded that future research on recycling EAF slag should focus on separation techniques that diversify the recycling options for EAF slag, thereby increasing the waste product’s recycling rate.

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