Phase-pure mullite from Kaolinite

Abstract

Sintering of kaolinite in the presence of certain carbonate mineralizers, viz., CaCo3, Na2CO3, and K2CO3, has been conducted at 950°-1350°C. The influence of these mineralizers at the above temperatures is evaluated using XRD and SEM techniques. A comparative study of phase formation of the above compositions shows that the sodium- and calcium-fluxed samples give rise to multiphase systems, while K2CO3-incorporated samples give phase-pure mullite. The observation that kaolinite in the presence of K2CO3 can act as a precursor material for phase-pure mullite is of great industrial significance.