A New Method to Predict Final Products of Red Mud-Slag-Based Alkali-Activated Materials Using Complete Phase Analysis of Precursors

Abstract

This paper presents a new method for predicting the final products of red mud-slag-based alkali-activated materials (RM-AAMs) using comprehensive phase analysis. As the first step, a quantitative method by X-ray diffraction (XRD) was used to analyze six different types of red mud and ground-granulated blast-furnace slag (GGBS). Secondly, X-ray fluorescence (XRF) was employed to determine the bulk elemental oxide contents of the precursors. A procedure combining XRD and XRF was then used to quantify both the crystalline and amorphous components of the precursors. In addition to investigating precursors, soluble silica from sodium silicate has been considered in calculating reactive silica. The research includes forty sets of alkali-activated samples using various activators with different concentrations. The XRD results of hardened paste samples revealed that the method could successfully predict the final products of RM-AAMs. By predicting the final products of the alkali-activation process, the optimization of raw material types and contents will be more efficient. For example, in the case of having C-S-H as the final product, adding substances with high reactive alumina would be unnecessary.