Experimental study on characterization of lime-based mineral carbonation reaction and CO₂ sequestration

This paper reports for the first time the use and application of a novel technique in the characterization of mineral carbonation reaction and CO₂ sequestration in soil stabilization using flow meters. Soils based on SiO₂ with two different sizes were tested. Lime (Ca(OH)₂) was used as the reactant. Instant CO₂ flow rate (L/min), total CO₂ volume (L), temperature (°C), and absolute pressure (kPa) were monitored and recorded for 1 h by flow meters connected to the mold inlet and outlet. It was determined that the mineral carbonation reaction started in the first seconds and ended before the 5th minute. The mineral carbonation is a short-term and potential reaction, and it is not a time-dependent reaction. It is separated from other carbonation reactions with these characteristics. The highest CO₂ captured value was obtained in the soil mixed with 5% lime, where fines were not used. The second highest CO₂ captured value was obtained in soil mixed with 1% lime, where fines were not used. CO₂ captured with 1% lime is more than CO₂ captured with 5% lime in the soil containing fines. Accordingly, 1-5% lime can be used in soil carbonation studies. According to the soil properties, the highest CO₂ captured and the CO₂ efficiency was achieved with the use of 6-7% water by weight.