Effect of mineral and phase composition of starting mixtures on solid-phase synthesis of cordierite

Abstract

The paper examines the phase transformations and synthesis of cordierite under solid-phase sintering using different natural and synthetic minerals, including binary compounds (mullite, spinel, enstatite) formed in intermediate stages. It is established that the synthesis of cordierite takes two stages: formation of three thermodynamically stable binary oxide compounds such as magnesium-aluminum spinel, mullite, and enstatite and formation of cordierite from a multiphase mixture containing, besides binary compounds, free crystalline α-Al 2 O 3 and SiO 2 oxides.

Influence of Mechanical Activation on the Phase Formation in the Synthesis of Cordierite from Talc and Andalusite

“…The mechanism of cordierite phase formation is complex. There are many intermediate phases, e.g., sapphirine, mullite, enstatite, spinel, associated in the chemical reaction to form cordierite[9]. The phase formation of cordierite in this study could be the reaction between andalusite, enstatite and silica, as shown in eq.2 while enstatite and amorphous silica came from thermal decomposition of talc (eq.1) [4,10].…”