The effect of TiO₂addition on the preparation and phase transformation for precursor β-spodumene powders

Fine β-spodumene-type amorphous powders were obtained through sol-gel techniques using Si(OC₂H₅)₄, Al (OC₂H₅)₃, LiOCH₃, and Ti(OC₂H₅)₄as the starting metal alkoxides. Differential thermal analysis (DTA), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron diffraction (ED) analysis were utilized to study the phase transformation behavior of the LAST gels. The viscosity of the LAST solution increased abruptly at longer time when the TiO₂content was increased. As the TiO₂content was increased, the peak position of β-spodumene phase formation in DTA curves was shifted to a lower temperature. For calcination of LAST gels at 800°-1200 °C, the crystallized phases are composed of the major phase of β-spodumene and a minor phase of rutile (TiO₂). Unlike earlier studies, heating the dried LAST gels from 800 °C to 1200 °C did not show β-eucryptite, nor found γ-spodumene.