Alkali-activation of ferrum-rich synthetic slags
The formation mechanism of alkali-activated materials from two ferrum-rich synthetic slags has been assessed recently.
In recent years alkali-activated materials have expanded to encompass Fe-rich precursors in addition to the more commonly employed aluminosilicate precursors. The formation mechanism of alkali-activated materials from two Fe-rich synthetic slags has been assessed by employing in-situ X-ray total scattering and subsequent pair distribution function analysis.
Three reaction stages
The evolution of the local atom-atom correlations reveals three reaction stages. After the dissolution of Fe-silicate clusters from the slag, a binder phase is formed with Fe in both Fe2+ and Fe3+ oxidation states. The Fe2+ state is present in the form of trioctahedral layers, similar to those in Fe(OH)2, while the Fe3+ is likely located in the polymerised silicate network. Exposure to air causes the Fe2+ species to transition to the Fe3+ state.
The study is published in: Cement and Concrete Research Volume 122, August 2019, Pages 179-188.
