Effect of water content on accelerated carbonation of municipal solid waste incinerator bottom ash for CO2 capture

For comparison of different water-to-solid ratio for the accelerated carbonation of municipal solid waste incinerator (MSWI) bottom ash for CO2 capture, it is necessary to understand the morphological changes of bottom ash as a carbonation reaction. Only the water-to-solid ratio (W/S) at atmospheric pressure was controlled from 0.3 to 10 dm3/kg and the CO2 concentration was kept constant at 30% while the reaction temperature was held at 20oC. The result of an XRD analysis indicated that portlandite, ettringite,and hydrocalumite in untreated bottom ash could combine with CO2 to form mainly an amorphous Al-material and calcite. In the case of 10 W/S, the amount of CO2 reacted with bottom ash approached the maximum value after 120 min reaction time, whereas the reaction at 0.3 S/W was scarcely carbonated after 60 min because of encapsulation effect.