Adjustment of Suspension Densities

As described above, crystallizers are operated with suspension densities of between 15 and 25% by mass. Suspension densities lower than 15% by mass increase the risk of primary nucleation and the probability of incrustations, while suspension densities greater than 25% by mass cause a greater attrition and increase the probability of deposits. 

In the second case, attention has to be paid to secondary effects. The recirculation of mother liquor is of course only possible if after the separation of the crystals there is still enough mother liquor remaining, which is not always the case, particularly with viscous mother liquors. It should also be ensured that before recirculation, all crystal nuclei and crystals are removed by heating or the addition of solvent. Otherwise, the crystal size distribution of the crystallizer will deteriorate. 

4 Pohlisch, J. (1987) Einjluss von mechanischer Beeinjlussung und Abrieb auf die Komgroiienverteilung in KuhlungskristaUisatoren. Dissertation, Technische Universitilt Munchen. 

7 Bamforth, A.W. (1965) Industrial Crystallisation, Leonard Hill, London. 

8 Hofmann, G. (1983) Ein Oslo-Kristallisator fitr lange Reisezeiten, Vortrag zur GVC-FA Kristallisation, Deggendorf, Bayern. 

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