Metakaolin is a calcined product of the clay mineral kaolinite. The particle size of metakaolin is smaller than
cement particles, but not as fine as silica fume.

When kaolinite, a layered silicate mineral with a distance of 7,13 Å between the layer of SiO2 and Al2O3 is
heated, the water contained between the layers is evaporated and the kaolinite is activated for eaction with
Metakaolin, kaolinite, pozzolanic
Calcined between 600° and 850°C the kaolin is transformed to an amorphous phase called metakaolin.
This mineral is activated and metastable. Metakaolin can then react with cement and lime.

Heating above 900°C produces mullite, a non pozzolanic material.

more info: Dr. Denis Bezard - are-questions-xya34[at] - phone: +43 (0)2252 45970