Thermal Dehydration of Monohydrocalcite: Overall Kinetics and Physico-geometrical Mechanisms

Monohydrocalcite (CaCO3·H2O: MHC) is similar in composition and synthetic conditions to hydrated amorphous calcium carbonate (ACC), which is focused recently as a key intermediate compound of biomineralization and biomimetic mineralization of calcium carbonate polymorphs. Detailed comparisons of the...

Full description

Saved in:
Bibliographic Details
Published in:The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2011-09, Vol.115 (38), p.10491-10501
Main Authors: Kimura, Tomoyasu, Koga, Nobuyoshi
Format: Article
Language:English
Subjects:
A: Kinetics, Spectroscopy
Calcite
Calcium carbonate
Calcium Carbonate - chemistry
Crystal growth
Crystal structure
Dehydration
Kinetics
Mineralization
Nucleation
Particle Size
Reaction kinetics
Surface Properties
Temperature
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Monohydrocalcite (CaCO3·H2O: MHC) is similar in composition and synthetic conditions to hydrated amorphous calcium carbonate (ACC), which is focused recently as a key intermediate compound of biomineralization and biomimetic mineralization of calcium carbonate polymorphs. Detailed comparisons of the physicochemical property and reactivity of those hydrated calcium carbonates are required for obtaining fundamental information on the relevancy of those compounds in the mineralization processes. In the present study, kinetics of the thermal dehydration of spherical particles of crystalline MHC was investigated in view of physico-geometrical mechanism. The reaction process was traced systematically by means of thermogravimetry under three different modes of temperature program. A distinguished induction period for the thermal dehydration and cracking of the surface product layer on the way of the established reaction were identified as the characteristic events of the reaction. By interpreting the kinetic results in association with the morphological changes of the reactant particles during the course of reaction, it was revealed that nucleation and crystal growth of calcite regulate the overall kinetics of the thermal dehydration of MHC. In comparison with the thermal dehydration of hydrated ACC, which produces anhydrous ACC as the solid product, the kinetic characteristics of the thermal dehydration of MHC were discussed from the viewpoint of physico-geometry of the component processes.
ISSN:1089-5639
1520-5215
DOI:10.1021/jp206654n