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Attrition and secondary nucleation in crystallizers
Author(s) -
Mersmann Alfons,
Sangl Reinhard,
Kind Matthias,
Pohlisch Joachim
Publication year - 1988
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.270110112
Subject(s) - nucleation , attrition , crystal (programming language) , crystal growth , suspension (topology) , chemistry , materials science , thermodynamics , crystallography , mineralogy , mathematics , physics , computer science , medicine , dentistry , homotopy , pure mathematics , programming language
The mean crystal size of coarse crystalline products is determined by secondary nucleation and crystal growth. Secondary unclei are mainly produced by contacts of crystals with parts of the crystallizer or with other crystals. As a consequence, attrition effects are very important. In this paper, a model is proposed in order to calculate the attrition rate of crystals, depending on the physical properties of the crystalline product, the geometry of the crystallizer and on the operating conditions such as the stirrer speed or the suspension density. The effective rate of secondary nucleation can be expressed in terms of the attrition rate by introducing effective values for number and size of attrition particles. Finally, a scale‐up criterion based on this model is derived. This criterion allows to predict effective rates of secondary nucleation and mean crystal sizes if data obtained in a laboratory crystallizer are available.