Le mécanisme de la transformation thermique de la métakaolinite

Publisher Website
Google Scholar
Abstract
A review of the most recent studies concerning the thermal transformations of metakaolinite in the range 900-1 000 °C is presented. An agreement is found between the results obtained with several physico-chemical techniques (absolute density measurements, radial electron distribution, X-Ray fluorescence, infrared spectroscopy), pointing to the transformation of metakaolinite into mullite through two parallel routes : the first one involves a complete segregation of ill crystallized silica and alumina, mullite being formed above 1 000 °C through the recombination of the segregated phases ; the second one involves the transformation into mullite without any segregation. By introducing selected mineralizers in a well-dispersed state in the metakaolinite, it is possible to direct selectively its transformation : for instance MgO promotes the complete segregation mechanism and the formation of gamma-alumina, whereas CaO promotes the direct formation of mullite.

This publication has 0 references indexed in Scilit: