Study of dispersed solid-phase ontogenesis using hierarchical structure data

Abstract

Ontogenesis of the dispersed solid phase of BaCO₃ has been studied under the conditions of fast reagent mixing. Crystallization was followed by high-resolution electron microscopy. It was found, on retarding the ageing process with EDTA, that the formation of the solid phase is stepwise: individual microcrystals to primary aggregates to secondary aggregates to pseudo-dendrites. Etching the pseudo-dendrites with EDTA shows the presence of the same levels of hierarchical structure. The experimentally determined crystal-size distribution agrees well with that previously reported. It is, therefore, possible to evaluate the ontogenesis of the solid phase from the morphology of the crystals at the end of crystallization.