Novel Method to Estimate the Linear Growth Rate of Submicrometric Calcite Produced in a Triphasic Gas−Liquid−Solid System - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue Crystal Growth & Design Année : 2009

Novel Method to Estimate the Linear Growth Rate of Submicrometric Calcite Produced in a Triphasic Gas−Liquid−Solid System

Résumé

The linear growth rate is an essential parameter to describe and simulate the crystal growth processes of solid materials. Concerning the calcite mineral, indirect methods (by depletion of calcium concentration) and direct methods (ex. using microscopic measurements) have been reported in the literature. Here, homogeneous (solution−solution) or heterogeneous (solution−solid) systems are systematically considered. Conversely, the estimation of linear growth rate of calcite for the triphasic gas−liquid−solid systems under high gas pressure and temperature has not been reported in the literature to the best of our knowledge. In the present study, we propose a new method to estimate the linear growth initial rate of submicrometric calcite produced in a triphasic gas−liquid−solid system under high gas pressure (55 and 90 bar) and moderated to high temperature (30 and 90 °C) by using Rietveld refinements of X-ray diffraction (XRD) patterns. These Rietveld refinements allowed the estimation on the variation of the coherent domain average size r (nm) with reaction time t (s). Then, a kinetic pseudo-second-order model was satisfactory used to fit the experimental−calculated data and determine the linear growth initial rate of submicrometric calcite. The results showed that the values of linear growth rate of calcite were equivalents for both systems, i.e., 0.14 nm/s at 30 °C and 55 bar and 0.12 nm/s at 90 °C and 90 bar. However, the average size of calcite crystals, here expressed as a maximum of coherent domain average size, was clearly higher at 90 °C and 90 bar (174 nm) than at 30 °C and 55 bar (63 nm). The main advantage for this method is the possibility to estimate the linear growth rate of crystalline fine particles (>40 nm) growing in triphasic gas−liquid−solid systems. Here, it is considered that depressurization of cell reaction has insignificant physicochemical effect on the solid precipitates; obviously, this is not the case for the interacting solutions.

Domaines

Minéralogie
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Dates et versions

insu-00426614 , version 1 (27-10-2009)

Identifiants

Citer

German Montes-Hernandez, Alejandro Fernandez-Martinez, François Renard. Novel Method to Estimate the Linear Growth Rate of Submicrometric Calcite Produced in a Triphasic Gas−Liquid−Solid System. Crystal Growth & Design, 2009, 9 (10), pp.4567-4573. ⟨10.1021/cg9005778⟩. ⟨insu-00426614⟩
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