Collect. Czech. Chem. Commun. 1986, 51, 2473-2480

Crystallization kinetics for the system CuSO4-ZnSO4-H2O forming solid solutions

Jaroslav Nývlt, Věra Šnoblová and Miloslav Karel

Institute of Inorganic Chemistry, Czechoslovak Academy of Sciences, 160 00 Prague 6


The three-component system CuSO4-ZnSO4-H2O forms three types of solid solution. Metastable zone widths measured for selected solution compositions at two cooling rates were used to calculate the kinetic parameters of nucleation. The rate of crystal growth was measured by the fluidized bed method. The results show that the addition of Zn2+ to a solution of CuSO4 increases both the nucleation and crystal growth rates, whereas Cu2+ added to a solution of ZnSO4 retards the nucleation rate and slightly increases the rate of crystal growth. The nucleation rate (the metastable zone width) is substantially more sensitive to the addition of a second component than is the rate of crystal growth. The crystal growth rate is controlled by a diffusion mechanism.