The effect of leaching temperature on kaolinite and meta-kaolin dissolution and zeolite re-precipitation

Abstract The effect of temperature on leaching-precipitation kinetics of both meta-kaolin and kaolinite was investigated. The dissolution of kaolin is the overall rate limiting step and only sodalite appeared as the final zeolite product for all tested temperatures within the reaction time. However, for meta-kaolin, an amorphous zeolite precursor, zeolite LTA and sodalite appeared as zeolite products at different temperatures within the specified time. In addition, the precipitation and dissolution rate of amorphous zeolite precursors appear to be the rate limiting step for meta-kaolin feed. For early stage dissolution of meta-kaolin, identification of XRD-amorphous phases between meta-kaolin and amorphous zeolite precursor was confirmed by SEM-EDS elemental analysis.