Investigation of the carbonation mechanisms and kinetics in binary systems with C2S and Ca-Mg silicates

This is the authors' abstract. We don't add key points for this paper.

This study investigates the interaction of two binary systems, consisting of belite (C 2 S) with Ca-Mg silicates in terms of its reaction behavior. Experiments were conducted using mixtures containing 60 % belite (blend of β- and γ-C 2 S) combined with bredigite (C 7 MS 4 ) and akermanite (C 2 MS 2 ). The reactions were carried out in a custom-designed wet reactor, with continuous monitoring of pH and temperature to capture real-time data on system dynamics. Various analytical methods were applied to characterize the reactions. Time-resolved solution and solid analyses enabled a detailed investigation of the reaction kinetics and identification of key phases in the carbonation process. Significant differences in the reaction kinetics were identified between the two investigated systems. In the C 2 S-C 7 MS 4 system, both reactants showed a similar carbonation behavior, whereas in the C 2 S-C 2 MS 2 system, akermanite displayed a time-shifted onset of the carbonation reaction. The carbonation reaction can be divided into two main stages, each controlled by different parameters. The primary products include CaCO 3 (vaterite, aragonite, calcite), amorphous CaCO 3 (ACc), and amorphous silica gel.