Scale-up of stirred crystallisers. Batch precipitation of aluminium potassium sulphate

Abstract

Aluminium potassium sulphate has been precipitated batchwise by mixing equal volumes of 0.6 mol/l solutions of potassium sulphate and aluminium sulphate with eventual addition of water in advance. The experiments were performed at 20 and 25 °C in the volume 100 to 200 cm3 and in the volume 0.021 m3. From the size distribution of product crystals, the mean size of crystals has been evaluated and calculated the system kinetic constant of crystallization BN. The system constant is different in both series of experiments and can be correlated with the size of the crystallizer or with mixing intensity. Its value and the value of relative kinetic exponent g/n is comparable with the values obtained in experiments with cooling of solutions.