Effect of Brine Saturation on Carbonation of Coal Fly Ash for Mineral Sequestration of CO2

Mineral sequestration with alkaline waste materials is being studied extensively for its application as a way of reducing the increased level of CO2 in the atmosphere. Coal combustion fly ash has the potential to react with CO2 to form minerals which are stable over geological times. For industrial level application of this concept, the mineralization reaction is required to enhance. The acceleration of the reaction is done through ex situ carbonation inside the reactors. The mineral carbonation reaction can be made more efficient through mixing the alkaline material with brine. Therefore the objective of the present study was to evaluate the effect of brine saturation of coal fly ash on the rate and the efficiency of CO2 sequestration. Three types of Australian fly ashes (Loy Yang, Yallourn and Hazel Wood) were saturated with brine and then carbonated inside a pressure vessel at 3 MPa CO2 pressure and 40 degrees C. Then the weight gain after carbonation was measured to estimate the sequestration potential. As a control another set of carbonation tests were performed replacing brine with water. Results showed a positive effect from brine on the rate and the efficiency of carbonation of coal fly ash.