“…High proportions (commonly >60%) of an Al-Si glassy matrix containing minor and variable contents of Ca, Fe, Na, K, Ti, Mg, and Mn, with minor and variable amounts of a number of crystalline phases (most commonly quartz, mullite, lime, hematite, magnetite, feldspars, gypsum and traces of anhydrite, alkali sulfates, calcium silicate and aluminate, sillimanite, cristobalite-trydimite, wollastonite, and Fe-Al spinels) are the main components of pulverised-coal-(co)-combustion (PCC) fly ashes [1][2][3][4][5][6][7]. The amorphous Al-Si glass strongly influences the reactivity of the fly ashes and plays a key role in their subsequent applications as a pozzolanic additive, for the synthesis of zeolites, or for the fabrication of geopolymers [2,6].…”