Influence of inorganic admixtures on the 11Â Ã -tobermorite formation prepared from steel slags: XRD and FTIR analysis

Calcium silicate hydrate is synthesized from steel slag by adding lime and quartz by dynamic hydrothermal method at 185 °C. The products mainly consist of disordered calcium silicate hydrate, but more crystallized phase such as 11 Å-tobermorite forms for the presence of inorganic admixtures. The formation of tobermorite is affected by the types of ions according to XRD and FTIR results. Adding 2% crystallized tobermorite is beneficial to form the ordered structure; alkali cations and SO42− anions are effective accelerators; Al3+ plays a role of stabilization during the reaction. The products also vary with the initial alkalinities of steel slag.