Optimization of Manufacturing of Precipitated Calcium Carbonate under Supersaturated Carbon Dioxide Conditions

In this research, the fundamental characteristics of precipitated calcium carbonate (PCC) production were examined using CO₂-supersaturated water. When CaCl₂ was injected, the pH rapidly decreased due to CaCO₃ production, making it necessary to control the injection of the calcium source and the alkali step by step. Additionally, the total carbonate removal rate reached 99.9% due to CaCO₃ formation within 1 hour of reaction time. A pilot plant of PCC production system with recycled flow rates of 2.0 and 5.0 L/min was designed and operated with CO₂-supersaturated water. The polymorphs and particle size of CaCO₃ were evaluated based on the flowrate of CO₂ supersaturated water and pH levels (9.5 and 10.0). The PCC particles recovered under the tested flowrates were all a mixture of calcite and vaterite. The average particle size of vaterite at 2 L/min (3.0 - 40.0 ㎛) was smaller than that at 5 L/min (6.0 - 22.0 ㎛). At a flow rate of 2 L/min, it was possible to separate PCC particles by size according to the hopper location. In contrast, as the pH increased the proportion of calcite tended to increase.