Effect of Particle Size on Carbonation Properties of Ternesite

Ternesite has been proven to possess excellent carbonation activity. This study focuses on optimizing the carbonation behavior of ternesite by exploring the influence of the particle size on the process. Specifically, it investigates the effects of particle size and carbonation duration on the compressive strength, carbonation degree, and CO2 sequestration capacity of ternesite. Additionally, the phase compositions of the carbonation products were analyzed using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA), while the underlying mechanisms of the carbonation reaction are also discussed. The results show that reducing the particle size of ternesite accelerates its dissolution, which, in turn, enhances the carbonation degree and CO2 sequestration. The maximum carbonation degree and CO2 sequestration values achieved were 72.1% and 233.1 g/kg, respectively. Calcite and vaterite were identified as the primary carbonation products, and smaller particle sizes were found to facilitate the formation of these carbonates. Notably, particle refinement exerts a dual effect on the pressed specimens. Ternesite with a moderate particle size exhibited high reactivity and sustained carbonation capacity, leading to a compressive strength of 101.7 MPa. However, excessively fine particle sizes lead to the rapid formation of a large quantity of carbonation products in the early stage, which refines the pore structure and thereby hinders the inward diffusion of CO2. Consequently, the compressive strength of ternesite with the smallest particle size reached 41.0 MPa. These findings provide theoretical support for improving the carbonation efficiency of ternesite in practical applications.