Solvothermal recrystallization of α-calcium sulfate hemihydrate: Batch reactor experiments and kinetic modelling
| Autor: | Fabienne Espitalier, Fabien Baillon, Nayane Macedo Portela da Silva, Alain Gaunand, Yi Rong |
|---|---|
| Přispěvatelé: | Centre Thermodynamique des Procédés (CTP), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement (RAPSODEE), Centre National de la Recherche Scientifique (CNRS)-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT) |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Gypsum
crystallization Batch reactor Kinetics Nucleation dissolution 02 engineering and technology engineering.material 010402 general chemistry 01 natural sciences law.invention Inorganic Chemistry modelling calcium sulfate [CHIM.GENI]Chemical Sciences/Chemical engineering law Materials Chemistry Crystallization Dissolution Aqueous solution Chemistry Recrystallization (metallurgy) 021001 nanoscience & nanotechnology Condensed Matter Physics 6. Clean water gypsum 0104 chemical sciences Crystallography Chemical engineering engineering 0210 nano-technology |
| Zdroj: | Journal of Crystal Growth Journal of Crystal Growth, Elsevier, 2017, 472, p.46-53. ⟨10.1016/j.jcrysgro.2017.02.010⟩ |
| ISSN: | 0022-0248 |
| Popis: | International audience; Under appropriate temperature conditions, natural gypsum CaSO4·2H2O, dispersed in an aqueous solution, turns into calcium hemihydrate CaSO4·½H2O. This transformation is performed in a 2 L stirred baffled reactor, where the temperature increase is measured and controlled on line. The water content of the suspension and its size distribution are measured on samples during the transformation. Experiments are achieved at nominal temperature of 140 °C, with three initial solid mass fractions 0.5, 0.33 and 0.25. The transformation takes place through a dissolution followed by re-crystallization. A model is proposed which takes into account the size distribution of the particles of gypsum, their dissolution rate, primary and secondary nucleation and growth rates of calcium hemihydrate. The set of equations is solved with a MATLAB software, which allows to test the assumptions on the kinetics of the transformation and fit their parameters. A satisfying representation of the variations of the extent of transformation and of volume and surface mean diameters of the suspension is obtained. |
| Databáze: | OpenAIRE |
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