title: Optimized carbonation of magnesium silicate mineral for CO2 storage.
abstract: The global ambition of reducing the carbon dioxide emission makes sequestration reactions attractive as an option of storing CO2. One promising environmentally benign technology is based on forming thermodynamically stable carbonated minerals, with the drawback that these reactions usually have low conversion rates. In this work, the carbonation reaction of Mg rich olivine, Mg2SiO4, under supercritical conditions has been studied. The reaction produces MgCO3 at elevated temperature and pressure, with the addition of NaHCO3 and NaCl to improve the reaction rates. A sequestration rate of 70% was achieved within 2 h, using olivine particles of sub-10 μm, whereas 100% conversion was achieved in 4 h. This is one of the fastest complete conversions for this reaction reported to date. The CO2 sequestration rate is found to be highly dependent on the applied temperature and pressure, as well as the addition of NaHCO3. In contrast, adding NaCl was found to have limited effect on the reaction rate. The roles of NaHCO3 and NaCl as catalysts are discussed and especially how their effect changes with increased olivine particle size. The products have been characterized by Rietveld refinement of powder X-ray diffraction, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy revealing the formation of amorphous silica and micrometer-sized magnesium carbonate crystals.
authors: Center for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University , DK-8000 Aarhus C, Denmark.
authors: Espen
authors: E
authors: Eikeland
authors: Anders Bank
authors: AB
authors: Blichfeld
authors: Christoffer
authors: C
authors: Tyrsted
authors: Anca
authors: A
authors: Jensen
authors: Bo Brummerstedt
authors: BB
authors: Iversen
keywords: CO2 capture; CSU; carbonation; magnesium silicates; reducing CO2 emission; sequestration; storage and utilization