On the kinetics of crystallization of zinc oxalate (III). Effect of supersaturation

Abstract

AbstractThe crystallization kinetics of zinc oxalate at different supersaturations was studied by a turbidimetry method. It was found that the curves optically registered by this method can be quantitatively characterized at intial supersaturations lower than 4.51. The graphically differentiated curves showed that the maximum crystallization rate could be fitted by equation Vmax ≅ K(C–C0)2, Where C and C0 are the initial and the equilibrium concentrations, respectively. The crystallization rates after the maximum follow the same equation depending on the absolute supersaturation at a given moment. A linear dependence between the rate constants and the supersaturations at the maximum crystallization rates is found. This dependence is determined by the inversely proportional correlation of the distances between the steps of growth with the supersaturation given by equation of the distances between the steps of growth with the supersaturation given by equation (8). The activation growth energy E* = 7.1 kcal/mole is determined from the straight line obtained.