Issue
J. Phys. Colloques
Volume 47, Number C1, Février 1986
Thirteenth International Conference on Science of Ceramics
Page(s) C1-527 - C1-531
DOI https://doi.org/10.1051/jphyscol:1986179
Thirteenth International Conference on Science of Ceramics

J. Phys. Colloques 47 (1986) C1-527-C1-531

DOI: 10.1051/jphyscol:1986179

MICROSTRUCTURE DEVELOPMENT OF Li2CO3-CaCO3 EUTECTIC MIXTURE IN CO2 (g) AND N2 (g) ENVIRONMENTS

D. BERUTO1, 2, M. GIORDANI1 et R. BOTTER1

1  Istituto di Chimica, Facoltà di Engegneria, Università di Genova, Fiera del Mare, Pad. D - Piazzale J. F. Kennedy, I-16129 Genova, Italy
2  Material and Molecular Research Division, L.B.L., University of California, Berkeley, U.S.A.


Résumé
On a étudié la formation des microstructures de Li2CO3, de CaCO3 et de mélanges eutectiques Li2CO3-CaCO3 sous CO2(g) et N2(g) à 800 K. A cette température CO2(g) favorise le frittage de CaCO3 et limite la croissance des crystallites de Li2CO3. Au dessus de la température eutectique (935 K) ces phénomènes s'observent aussi dans le mélange eutectique.


Abstract
Reaction between CaO powdevs and CO2(g) is often limited by the slow diffusion of CO2 through the CaCO3 product. Addition of Li2CO3 has been proved effective in modifying the CaCO3 layer, up and below the eutectic temperature (935 K). This study deals with the microstructure development of Li2CO3, CaCO3 and Li2CO3-CaCO3 eutectic mixture in CO2(g) and N2(g) at 800 K. At this temperature CO2(g) enhances the sintering of CaCO3 and reduces the grain growth of Li2CO3 crystallites. At temperatures below the eutectic one these features have been observed also within the eutectic mixture. Accordingly, the protective layer of CaCO3 formed in the CaO carbonatation has a more open microstructure, and the reaction rate between CaO and CO2 is increased.