The Characterization of Steel Slag by Alkali Activation

This paper presents a characterization analysis of alkali-activated steel slag. The effect of the ratio of steel slag and ferronickel slag, which are precursor materials, on the compressive strength of the alkali-activated materials was investigated. The combination of sodium hydroxide solution with a concentration of 15 moles and sodium silicate was used as the alkaline activator. The ratio between steel slag and alkaline liquid was fixed at 3.31 for all mixtures, and ambient curing conditions (20 ˚C - 25˚C) were maintained throughout the experiment. The results indicated that alkali-activated steel slag achieved a high compressive strength of 21.56 MPa at 14 days of curing, which is superior to the 50/50 Fe/SS alkali-activated slag that only reached 16.75 MPa. Additionally, the alkali-activated steel slag exhibited better water absorption than its 50/50 counterpart at 7 days of curing. The activation of steel slag contributed to the presence of gehlenite, larnite, akermanite, and magnetite. Furthermore, the alkali-activated steel slag demonstrated a vibration of the Si-O bonds at a wave number of 970.46 cm −1, attributed to the calcium silicate hydrate.