Studies on nucleation phenomena occurring in aqueous solutions supersaturated with calcium sulfate

The results of a set of experiments designed to delineate the nucleation rate, supersaturation, temperature surface for the system CaSO4•2H2O/H2O are reported. The data were obtained using the droplet technique coupled with in situ generation of SO42− under the conditions that dS/dt was large during the early part of the induction period and it was zero during the actual nucleation events. The observed shape of the surface is compared with that suggested by the classical theory of nucleation and differences are commented on. The critical parameters important in classical nucleation theory are reported.