GROWTH-KINETICS OF SODIUM PERBORATE FROM BATCH CRYSTALLIZATION

The size distribution of sodium perborate crystals was continually mon itored using a Malvern sizer during batch crystallization from aqueous solutions carried out under falling supersaturation established at th e experiment onset. The growth rate was determined from the time shift of the crystal size distribution expressed in cumulative oversize num bers. The size independent overall growth rate was first order with re spect to supersaturation for crystals larger than 150 mu m. Crystals b etween 20 and 150 mu m exhibited a significant size-dependent growth r ate. Furthermore, the fraction of crystals smaller than 20 mu m, forme d by primary nucleation, grew extremely slowly or did not grow at all.