Ground calcined alumina for input in a precursor composition for refractory material and method for obtaining same
AssigneeAluminium Pechiney
InventorsNicolas Martin, Christian Barthelemy
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Abstract
The invention concerns an additive-containing ground calcined alumina used as constituent of a refractory material precursor characterized in that it comprises an organofunctional silane, the organic function being typically an epoxy function, an alkyl function, an alcohol function or a diol function. Preferably said organofunctional silane is an oxyranyl-alkyl-silane, of chemical formula C9H20O5Si. Said additive-containing alumina can be obtained by adding said organofunctional silane during grinding to take advantage of its anti-caking properties, the intimate and homogeneous mixture being obtained as a result of grinding. It may also result from a post-grinding mixing.
Claims15
Ground calcined alumina with an additive comprising between 0.01 and 1% by weight of an organofunctional silane.
Method for obtaining a ground calcined alumina comprising calcining an alumina hydrate at a temperature of between 800° C. and 1300° C. for a period of half an hour to 4 hours, and grinding the calcined alumina in the presence of an organofunctional silane.
In a method for preparing a precursor for a refractory material comprising the steps of calcining alumina and grinding the calcined alumina to obtain a desired particle size,
- the improvement comprising grinding the calcined alumina in the presence of an organofunctional silane.
Dependencies are inferred from the claim text.