A new method for carbonating magnesia and its possible application to soil stabilization and CO2 capture. (20th June 2023) - Li, Wentao
Highlights: The soil with NaHCO3 + MgO has higher strength and stiffness than OPC treated soil. The formation of magnesium carbonates improves strength of soil with NaHCO3 + MgO. The new method of NaHCO3 + MgO is more convenient to operate on-site than MgO + CO2 . The use of NaHCO3 + MgO facilitates CO2 captures. The use of NaHCO3 + MgO has a significant economic benefit for soda industry. Abstract: Traditional MgO carbonation (MgO and gaseous CO2 ) is a promising and sustainable technique in construction fields. However, using this technique to treat in-field soils on a large scale presents problems associated with CO2 diffusion, carbonation conditions, and mixing processes. To address such problems, this study proposed a new method that used NaHCO3 as a CO2 carrier to carbonate MgO, and then the carbonated MgO is applied to treat soils. The engineering properties of the stabilized soil were investigated. A discussion on the technical and economic feasibility of this new method was followed. The results showed that the soil with MgO + NaHCO3 had better mechanical performance than that with OPC due to the formation of various magnesium carbonates. The new method would be more convenient to operate on-site than the traditional carbonation method and presented a strong economic potential for the soda industry. Overall, this method could be an upgrade to MgO carbonation.