Heat flow modeling in the alkaline activation process of fly ash

Abstract

Cement production plays an important role in strengthening the infrastructure of growing countries such as Colombia. However, the production of this material has a high energy cost and contributes to the emission of large amounts of CO2.  To address these environmental concerns, it is essential to explore alternative materials that can partially or completely replace traditional cement. Alkaline activated cement (AAC) has emerged as a promising candidate in this regard. Due to this, it is necessary to understand the process of alkaline activation and the variables that influence it. This research proposes a phenomenological-based semi-physical model, which predicts the performance of some variables that control alkaline activation: activator concentration (NaOH), heat flow, and degree of reaction. The model results show that with the increment of the activator concentration, the degree of reaction also increases. Furthermore, the model has an accurate response compared with the Freisleben-Hansen model. The integral square error criterion (ISE) was used in this comparison.