Accelerated Carbonation Technology of Reactive MgO-Stabilized Soil for Possible CO 2 Sequestration

Nowadays, the cement industry is under pressure to reduce the carbon footprint and energy demands of cement-based construction materials. Carbonation technology is a process that the Ca-/Mg- alkaline materials can react with CO2 to form stable carbonates, thus it is regarded as a potentially attractive technology of CO2 sequestration, including mineral carbonation, cement/concrete carbonation, and carbonation of reactive MgO-stabilized material. This paper investigates the CO2 uptake of reactive MgO-stabilized soils after accelerated carbonation under the high CO2 concentration (99.9%). The CO2 uptake is examined through the HNO3 acidification test and thermal analysis technology. Key results revealed that the carbonation of reactive MgO-stabilized soils could consume large amounts of water and CO2 to produce expansive carbonation products. The CO2 uptake is observably affected by several factors such as MgO content, water content, carbonation time and CO2 pressure. After the several hour’s carbonation (about 3–6 h), the CO2 uptake can basically achieves about 0.8–1.0 times matter quantity of reactive MgO.