This study investigates the comparison of influences of CO2 bubbling into the calcium hydroxide (Ca(OH)(2)) slurry through a microbubble generator (MBG) and an ordinary CO2 generator (OCG) on the preparation of calcite nanoparticles by a carbonation method. Each obtained precipitate was characterized using XRD. SEM and particle size analyses. During the carbonation process at each CO2 flow rates, it was determined that the MBG generates tiny bubbles whereas an increase in CO2 flow rates led to an increase bubble size when the OCG was used. The flow rate of CO2 was not an important parameter with using the MBG as calcite nanoparticles were prepared (< 125 nm) at each CO(2)flow rates. The necessary time for the complete reaction decreases with an increase in the CO2 flow rates through the MBG in comparison to the OCG. To produce calcite nanoparticles with a high production recovery in shorter times, the MBG should be adopted to the carbonation reactor.