- Title
- Effect of ethanol on the crystallization and phase transformation of MgCO3·3H2O in a MgCl2-CO2-NH3·H2O system
- Creator
- Cheng, Wenting; Zhang, Cuiyu; Cheng, Huaigang; Chen, Zuliang; Liao, Hongqiang; Cheng, Fangqin
- Relation
- Powder Technology Vol. 335, Issue 15 July 2018, p. 164-170
- Publisher Link
- http://dx.doi.org/10.1016/j.powtec.2018.04.063
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2018
- Description
- The effect of ethanol on the crystallization and phase transformation of MgCO3·3H2O in a MgCl2–CO2–NH3·H2O system was investigated at 40 °C. The obtained crystals were characterized by X-ray diffraction and scanning electron microscopy, and the phase transformation behaviors of the MgCO3·3H2O crystals were studied quantitatively using an established thermal analysis method. The results showed that ethanol played a key role in inhibiting the aggregation of MgCO3·3H2O crystals because the adsorption of ethanol molecules on nuclei surfaces was preferential to that of water molecules. Active Mg2+ ions could be separated from the nuclei surfaces when <30% ethanol was added, preventing secondary nucleation during the crystallization of MgCO3·3H2O. As a result, highly dispersed and stable MgCO3·3H2O rod crystals with smooth surfaces and uniform sizes (length of 25–30 μm and diameter of 2–3 μm) were successfully prepared with 30% ethanol at 40 °C. However, the rod-like MgCO3·3H2O crystals started to dissolve with >40% ethanol in solution, leading to the formation of more stable, flower-like crystals of 4MgCO3·Mg(OH)2·4H2O. The results of this study could contribute to the development of methods for controllable crystallization of MgCO3·3H2O.
- Subject
- crystallization; ethanol; MgCO3·3H2O; phase transformation
- Identifier
- http://hdl.handle.net/1959.13/1451910
- Identifier
- uon:44299
- Identifier
- ISSN:0032-5910
- Language
- eng
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