Influences of reaction temperature and reaction solution concentration on needle-like aragonite particle size

In this research, the synthesis of needle-like aragonite, which is one of CaCO3 polymorphs was conducted to utilize as a filler after CO2 fixation to CaCO3 in the CaCl2–Na2CO3–H2O reaction system without additives. Influences of temperature and solution concentration of reaction on aragonite particle size were investigated. When the concentration was 0.05 mol·dm−3, aragonite single phase was synthesized at or above 60 °C. On the other hand, calcite and vaterite coexisted in the main component of aragonite phase at 0.01 mol·dm−3 and 80 °C. From SEM observation, obtained aragonite shape was needle-like, and its particle size was from 4.3 to 8.8 µm when reaction conditions were from 60 to 85 °C and 0.01 to 0.05 mol·dm−3. Aragonite length was tended to be large with increasing the reaction temperature and decreasing the reaction concentration.