Synthesis of Calcium Carbonate Particles in Octylamine/Water Bilayer Systems

• Main Authors: Jun Wang, William B. White, James H. Adair
• Format: Article
• Language: English
• Published: Hosokawa Powder Technology Foundation 2014-02-01
• Series: KONA Powder and Particle Journal
• Subjects: powder; ceramics; chemical synthesis; raman spectroscopy; crystal structure
• Online Access: https://www.jstage.jst.go.jp/article/kona/31/0/31_2014005/_html/-char/en

Calcium carbonate particles with various shapes and morphologies were prepared via precipitation in an octylamine/water self-assembly bilayer systems. Crystal structure and shape of the CaCO3 particles were determined by the water to octylamine molar ratio R of the bilayer. At R = 16.0, phase pure calcite particles with a “hopper crystal” morphology were formed, the average particle size of the hopper crystal is 10 μm with well-defined edges on the hopper faces. Decrease the R ratio to 7.2 eventually leads to the formation of 3 μm tabular CaCO3 particles which are predominated by vaterite structure. For an intermediate R of 10.8, spherical vaterite aggregates and rhombohedral calcite particles were produced. Thermal decomposition of the CaCO3 particles was observed at around 710°C. The mechanism of particle evolution in the self-assembly bilayer, particularly the formation of “hopper crystal” calcite was discussed.