Effects of CO2 Bubble Size, CO2 Flow Rate and Calcium Source on the Size and Specific Surface Area of CaCO3 Particles

The effects of CO2 flow rate and calcium source on the particle size (PS) and specific surface area (SSA) of CaCO3 particles were evaluated using microbubble generator (MBG) and air diffuser (AD) systems. The carbonate mineralization (CM) and precipitated calcium carbonate (PCC) methods were employed to produce CaCO3 using gypsum and Ca(OH)2 as the calcium sources, respectively. The CaCO3 particles prepared using the MBG were smaller (with larger specific surface area) than those obtained using the conventional AD, regardless of the calcium source. The average PSs were 2–3 and 7–9 μm for the MBG and AD systems, respectively. Moreover, the PS and SSA of the particles prepared using the MBG were not greatly affected by the CO2 injection rate. This study clearly demonstrates that the use of an MBG ensures the stable production of fine CaCO3 particles using various calcium sources and a wider range of CO2 flow rates.