Kinetics and mechanism of topochemical transformations of phosphoric salts

A study was made on the topochemical processes of hydration-dehydration, am monation-deammonation, disproportionation and anionic condensation (certain of which can proceed concurrently) that occur during the production, stora ge and exploitation of phosphoric salts and phosphate materials. These proc esses which can be accompanied by complicated structural transformations an d sometimes by melting were shown to be satisfactorily described by the kno wn kinetic regularities. The detected deviations, that are associated with the anomalous influence of temperature, the gaseous phase, the size and hab it of the crystals and the ageing of samples on the process rate, were expl ained in terms of the localization peculiarities of the reactions proceedin g on the surface or in the bulk of the reactant.