Numéro
J. Phys. IV France
Volume 03, Numéro C7, Novembre 1993
The 3rd European Conference on Advanced Materials and Processes
Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés
Page(s) C7-1403 - C7-1406
DOI http://dx.doi.org/10.1051/jp4:19937215
The 3rd European Conference on Advanced Materials and Processes
Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés

J. Phys. IV France 03 (1993) C7-1403-C7-1406

DOI: 10.1051/jp4:19937215

Low-shrinkage refractories bonded with high-alumina cement mixed with colloidal silica

N. RICHARD, N. LEQUEUX and P. BOCH

Laboratoire Céramiques et Matériaux Minéraux, UA-CNRS, Matériaux Inorganiques, ESPCI, 10 rue Vauquelin, 75005 Paris, France


Abstract
Low-shrinkage refractories were prepared by bonding ceramic grains with high-alumina cement mixed with colloidal silica. The phases formed during hydration or heat treatment were studied by XRD and IR-spectroscopy.The main hydrated phases were CaO-Al2O3-10H2O (hydration at 20°C) and 3CaO-Al2O3-6H2O plus 2CaO-Al2O3-SiO2-8H2O (hydration at 50°C). 12CaO-7Al2O3 was the first phase that crystallised during thermal treatments. At [MATH], 12CaO-7Al2O3 reacts with silica to form anorthite (CaO-Al2O3-2SiO2) and gehlenite (2CaO-Al2O3-SiO2). Part of colloidal silica combines with calcium and aluminum to form cristobalite, which is stabilised in its [MATH]-form. Shrinkage was measured by dilatometry. The crystallisation phenomena are beneficial to reduce firing shrinkage. The stabilisation of [MATH]-cristobalite eliminates the dilatometric anomaly usually induced by the [MATH] transformation at [MATH] 200°C.



© EDP Sciences 1993