Alkali activation of fly ashes, Part I: Mechanical pre-processing for the improvement of the fly ash reactivity

Conference Dates

May 27-June 1, 2018


Fly ashes use to be heterogeneous materials as a function of the mineral origin of the coal burned in the power plant. The control of particle size distribution of fly ashes by a pre-mechanical treatment can improve the reactivity of some fly ashes and help to produce homogeneous materials for the fabrication of alkaline cements. In this paper original and pre-mechanical activated fly ashes (from different countries) were studied. The alkali activator used in all cases was an 8‑M NaOH solution. The reaction rate was determined through conduction calorimetry. Paste mechanical strength was determined on 1x1x6‑cm prismatic specimens. Both the starting ash and the reaction products were characterised by means of XRD and SEM/EDX. The results obtained show that effectively the pre-mechanical activation can help to obtain a good quality fly ash independent on the mineral origin of coal.

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