Reactive Andalusite: Properties and Application in Refractory Castable
1 DAMREC-IMERYS, 75007 Paris/France
2 CARRD-IMERYS, 9500 Villach/Austria
Revision
Volume 4, Issue 1, Pages 073 - 078
Abstract
It is very important to use a middle temperature (around 1000 °C) formed ceramic bonding that could workat high temperature (more than 1500 °C) for high performance refractories and ceramics. Damrec developsa new reactive bonding material starting from andalusite. A comparative reactivity study between thisreactive andalusite and one typical reactive alumina is made in this research work. The results show thatthe ceramic bonding from reactive andalusite starts around 950 °C.The origin of reactive andalusite formed ceramic bonding is following:• mullitisation of reactive andalusite from 950 °C giving silica glass on the surface of mullite-andalusite• merge of the silica glass each together: silica bonding• secondary mullite formation between the silica glass and the fine alumina: mullite bonding.The trial of applying this reactive andalusite in LCC refractory castable has been done. For castables withmicrosilica addition (3 –5 %), reactive andalusite develops the same level bonding strength as reactive aluminafrom middle temperature to high temperature.For free and very few microsilica castables, in middle temperature, the ceramic bonding created by reactiveandalusite has the same level of strength than ceramic bonding due to reactive alumina. But in high temperature,reactive andalusite develops a stronger bonding by creating a complementary ceramic bonding bya secondary mullite formation between the glass phase on the surface of andalusite-mullite and calcinedalumina.
Keywords
andalusite, reactive material, ceramic bonding, refractory matrix, refractory castable
References
[1] Hubert, P.: Andalusite: a reactive mineral for refractories. Damrec’s internal document, V1 (2001) 1–12
[2] Xiong, X.-Y.; Weissenbacher, M.; Ressler, A.; Van Den Heever, D.: A new refractory material: reactive andalusite. 47th Symposium on Refractory,
St. Louis, USA (2011) 49–62
Copyright
Göller Verlag GmbH
