Electric arc furnace slag is reported to contain considerable amount of free CaO which may cause volume swelling so that its application to construction material is very limitedly performed. Free CaO still remains in the slag with unreacted condition. Electric arc furnace slag can be classified into EOS (electric arc furnace oxidizing slag) and ERS (electric arc furnace reduction slag), and they have different chemical compositions and free CaO content. In the present work, free CaO in EOS and ERS are quantitatively evaluated through ethylene glycol method considering solution temperature, measuring period, aging period on site, air-exposure conditions, and ERS replacement ratio. EOS shows a reasonable level of CaO, basicity (CaO/SiO2), and free CaO content that can be used for construction materials, however ERS exceeds the critical level of usage. In the work comprehensive property evaluation of EOS and ERS is performed for utilization of electric arc furnace slag to construction materials, and the results are discussed.

Keywords: Electric arc furnace slag, free CaO, Electric arc furnace oxidizing slag(EOS), Electric arc furnace reduction slag(ERS), Ethylene glycol.