Role of mineralizers on the hexacelsian to celsian transformation in the barium aluminosilicate (BAS) system

The mechanism of additive-enhanced kinetics of the hexacelsian–celsian transformation in BAS was assessed by doping various mineralizers having different cationic radii and valence. The semi-quantitative data of XRD analysis indicate that an ionic valence of +3 is less efficient and ionic radii ranging from 0.68 to 1.12 Å are more effective in promoting celsian formation. Insights about the sites in which the doped cations reside are obtained by examining the possible defect structures developed in the mineralizer-containing hexacelsian. Oxygen- and barium-vacancies defects induced by the addition of mineralizers in BAS could assist the breaking of BaO or (Al, Si)O bonds and promote the polymorphic transformation.