Mineralogical Study of Thermally Activated Serpentine Dissolution Process for Direct Flue Gas CO2 Abatement By Mineral Carbonation

Direct flue gas mineral carbonation is an efficient way to reduce industrial greenhouse gas emissions. Along with other silicates, serpentine minerals show great potential for carbonation. Most of all, serpentine minerals represent a great interest due to their large availability and accessibility. With more than 2Gt of serpentine mining residues closed to industrial emitters, the abatement potential is very important in the Province of Quebec. Magnesium leaching is identified as carbonation limiting factor. However, magnesium is strongly bonded to hydroxyl groups inside of the serpentine structure. Thereby, serpentine needs to be heat activated to undergo a dehydroxylation process to reach sufficient carbonation rates. Such step is responsible for high energy demand and is very sensitive for the process application. Temperature and duration of the activation are the parameters to be controlled during the dehydroxylation process. This study proposes a mineralogical approach by using XRD and Rietveld Refinement method combined to flow through time resolved analysis (FT-TRA) and aqueous-phase mineral carbonation reaction in flue gas conditions experiments to understand and apprehend the impacts of the thermal treatment on the dissolution of serpentine and furthermore on the carbonation process.