Roughness effect on the overall growth rate of sucrose crystals

• Published in: Journal of crystal growth Vol. 310; no. 2; pp. 442 - 451
• Main Authors: Ferreira, A., Faria, N., Rocha, F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.01.2008; Elsevier
• Subjects: A1. Surface structure; A2. Growth from solutions; A2. Seed crystals; B1. Sucrose; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Growth from solutions; Materials science; Methods of crystal growth; physics of crystal growth; Physics; Solid-solid transitions; Specific phase transitions; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; B1. Sucrose; A1. Surface structure; A2. Seed crystals; A2. Growth from solutions; 61.72.Bb; 61.72.Hh; 81.10.−h; 81.10.Dn; Crystal growth; Scanning electron microscopy; Growth rate; 81.10.-h; 81.10.Dn; 61.72.Bb; 61.72.Hh; Crystallization; Roughness; Crystal seeds; Saccharose; Surface structure; Time dependence; Aqueous solutions; Supersaturated solution; Growth mechanism; Crystal faces; Fluidized beds; Growth from solution; A1. Surface structure; A2. Growth from solutions; A2. Seed crystals; B1. Sucrose
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2007.11.031

The roughness effect on crystal growth rate was investigated at 35 ∘ C in a fluidized bed crystallizer and in a batch crystallizer. The crystallization of sucrose in pure aqueous solutions was the study subject. The results show that the sucrose crystals exhibit time-dependent growth rate. The overall growth rate decreased continually with time until a constant value was reached, that corresponds to a decrease of 40% considering the experiments of 13 and 63 min duration in the fluidized bed crystallizer. The decrease of the growth rates with the contact time between crystals and supersaturated solution was interpreted in terms of the increase of surfaces’ roughness. According to SEM micrographs, the surface roughness increases significantly with residence time and supersaturation. The roughness appears to be the result of faulty integration of growth clusters in the crystal surface. The batch experiments show that the surface roughness acts like a strong impurity. The results were interpreted according to the Kubota–Mullin model.