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·dm¹³, 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·dm¹³ and 80 °C. From SEM observation, obtained aragonite shape was needle-like, and its particle size was from 4.3 to 8.8 ¯m when reaction conditions were from 60 to 85 °C and 0.01 to 0.05 mol·dm¹³. Aragonite length was tended to be large with increasing the reaction temperature and decreasing the reaction concentration.