Andalusite as a refractory material can be transformed to mullite and a silica-rich liquid phase in a temperature range of 1100-1600 C. In this paper, the influences of MgO and CaO mineralizers on transformation of andalusite to mullite were investigated. Different amounts of MgO and CaO were introduced to andalusite by solution (precipitation) method. Then the precipitated particles were pressed, dried, and fired at 1300, 1400, 1500, and 1600 C for 2 h. The microstructures of these samples were studied by XRD and SEM. The results showed that the addition of MgO and CaO affected mullitization of andalusite, so that the addition of these oxides increased the amount of mullite formation in andalusite.
