Potential reactivity assessment of mechanically activated kaolin as alternative cement precursor.

This work aims to assess the potential reactivity of a mechanically activated kaolin for its use as an alternative cement precursor. The mechanical activation was successfully achieved by grinding at different rotation speeds (250, 300, and 350 rpm) and times (60, 90, and 120 min), obtaining a highly amorphous and reactive material. The amorphization was monitored through XRD with amorphous content estimation and FTIR deconvolution. The potential reactivity was evaluated through chemical attacks, obtaining SiO 2 and Al 2 O 3 availabilities up to 95 wt% and 93 wt% of total SiO 2 and Al 2 O 3 content. XRD and FTIR also allowed the identification of the non-reactive phases on the insoluble residue after chemical attacks. NMR analysis revealed that part of the aluminium was in IV coordination, limiting the reactivity in the alkali activation process. This work demonstrated the effectiveness of mechanical activation as a greener treatment than thermal dehydroxylation to increase the raw kaolin's reactivity. • The effect of mechanical activation (MA) in kaolin's reactivity was evaluated. • MA enhances the reactivity of kaolin. • Grinding time and rotation speed's influence on kaolin's reactivity was revealed. • The MA of kaolin could lead to a higher amorphous content than in metakaolin. • The results demonstrate that activated kaolin is suitable as cement precursor. [ABSTRACT FROM AUTHOR]