10:00 AM - 10:15 AM
[MIS13-04] Synthesis of Aragonite Using the Carbonation Method and Control of Its Aspect Ratio
Keywords:Calcium carbonate, Aragonite, Carbon dioxide, Aspect ratio
Recent environmental problems demand the material development utilizing CO2 gas and transition from oil-based plastics to bio-based plastics. However, the mechanical strength of bio-base plastic is too weak to replace oil-based plastics. In this context, we have studied the development of CO2-based material to reinforce weak bio-plastics. According to the Halpin-Tsai model, the mechanical strength of composite materials depends on the morphology and elastic modulus of the reinforcement material. Here, we have synthesized aragonite, which exhibits a high aspect ratio morphology.
The synthesis of aragonite using CO2 gas was first achieved in 1967, and various synthesis conditions have been reported (Sakuma et al., 2025). From these previous studies, the preferable conditions for the synthesis of aragonite include the presence of additives such as Mg-salts and amines, and elevated temperatures. The source of Ca ions is preferably Ca(OH)2 due to its low cost. The highest aspect ratio achieved was 80 (Ota et al., 1995), but the control of the aspect ratio remains unclear.
In this study, we aimed to understand how to synthesize pure aragonite and control its aspect ratio. Calcium carbonate was synthesized by bubbling CO2 gas into heated Ca(OH)2-Mg salts mixed aqueous solutions. The time developement of precipitated crystals was analyzed using X-ray diffraction (XRD) and Raman spectroscopy. The reaction process was monitored by changes in solution pH. The direction of crystal growth was analyzed using the electron backscatter diffraction (EBSD) method.
As a result, the aragonite with a long axis length of 10 micrometer was precipitated within two hours of bubbling of CO2 gas, and we succeeded in controlling the aspect ratio by changing the conditions. In the presentation, we will discuss the synthesis conditions of pure aragonite and how to control the aspect ratio.
References
Sakuma, H., S. Suehara, H. Nakao, J.-D. Kim, K. Tamura (2025) Synthesis of needle-like aragonite using carbonation method: A review, J. Mineral. Petrol. Sci., 120, in press.
Ota, Y., S. Inui, T. Iwashita, T. Kasuga, Y. Abe (1995) Preparation of aragonite whiskers, J. Am. Ceram. Soc., 78, 1983-1984.
The synthesis of aragonite using CO2 gas was first achieved in 1967, and various synthesis conditions have been reported (Sakuma et al., 2025). From these previous studies, the preferable conditions for the synthesis of aragonite include the presence of additives such as Mg-salts and amines, and elevated temperatures. The source of Ca ions is preferably Ca(OH)2 due to its low cost. The highest aspect ratio achieved was 80 (Ota et al., 1995), but the control of the aspect ratio remains unclear.
In this study, we aimed to understand how to synthesize pure aragonite and control its aspect ratio. Calcium carbonate was synthesized by bubbling CO2 gas into heated Ca(OH)2-Mg salts mixed aqueous solutions. The time developement of precipitated crystals was analyzed using X-ray diffraction (XRD) and Raman spectroscopy. The reaction process was monitored by changes in solution pH. The direction of crystal growth was analyzed using the electron backscatter diffraction (EBSD) method.
As a result, the aragonite with a long axis length of 10 micrometer was precipitated within two hours of bubbling of CO2 gas, and we succeeded in controlling the aspect ratio by changing the conditions. In the presentation, we will discuss the synthesis conditions of pure aragonite and how to control the aspect ratio.
References
Sakuma, H., S. Suehara, H. Nakao, J.-D. Kim, K. Tamura (2025) Synthesis of needle-like aragonite using carbonation method: A review, J. Mineral. Petrol. Sci., 120, in press.
Ota, Y., S. Inui, T. Iwashita, T. Kasuga, Y. Abe (1995) Preparation of aragonite whiskers, J. Am. Ceram. Soc., 78, 1983-1984.