Growth kinetics of probertite in borax solutions in the presence of crystalline seeds

A method for analyzing data from seeded precipitation experiments was appli ed. It is possible to determine the dependence of the growth rate on supers aturation by applying this model to desupersaturation data, if there is no nucleation and the crystals maintain their original shapes and densities. T he suggested method was applied to desupersaturation data for probertite, N aCaB5O9. 5H(2)O, in Borax solution containing 28 wt % Na2B4O7 and crystalli ne probertite seeds at 368 K. The results showed that the growth rate is pr oportional to supersaturation. The overall rate constant was found to be de pendent on the amount of seeds. This dependence can be attributed to the ch ange of the density of precipitate during the precipitation. In the case of a small amount of crystalline seed (0.1 kg/100 kg of solution) the growth rate constants obtained from the suggested method and from the chronomal an alysis show good agreement and their average value was found as 7.58 x 10(- 6) kg of anhydrous probertite/(m(2).s.(kg of anhydrous probertite/100 kg of solution)).