Crystallization

Abstract

This article provides an overview of crystallization that can be used by scientists and engineers, regardless of their familiarity with the operation. Key aspects of the use of crystallization for separation, purification, or other purposes are covered; especially noteworthy is the coverage relating product purity, morphology, and size distribution to the kinetic phenomena of crystal nucleation and growth. Current studies have shown that crystallizer variables such as mixing and the rate at which supersaturation is generated influence the purity of recovered crystals. Crystal morphology can be affected by variables modifying inherent growth kinetics of crystal faces or by changing interfacial or solution properties. Molecular modeling is a tool to understand and predict morphologies or changes of morphologies due to additives/impurities. Theory is mixed with empiricism in showing the role of operating variables such as supersaturation, magma density, and agitation in determining crystallization kinetics. Methods are illustrated for coupling crystallization kinetics with population balances on continuous and batch crystallizers to determine crystal size distributions. In addition, the bases of using selective removal functions (clear‐liquor advance, classified‐fines removal, and classified‐product removal) to influence the characteristics of size distributions is presented. Qualitative characteristics of batch crystallizers are presented and the role nucleation plays in determining the general behavior of product size distributions from such systems is described. Finally, a summary of industrial practices and equipment is presented; both crystallization from solution and from the melt are included in the summary. Attention is given to the emerging importance of crystallization from the melt.

Ultrasound for Improved Crystallisation in Food Processing

“…The properties of the crystals obtained depend on these two steps and their relationship to each other. Qualitatively, when the rate of nucleation is high relative to the growth rate, crystals formed are small and numerous [78]. A detailed insight into the thermodynamics and fundamental aspects of crystallization can be obtained from many references [20,47,60].…”

Polyesters containing sulfur. VIII. New benzophenone‐derivative thiopolyesterdiols synthesis and characterization. Their use for thermoplastic polyurethanes preparation

“…1,2 The initial studies on PUs synthesis were based on simple diisocyanates and diols. Currently, PUs are extensively used as adhesives, coatings, foams, elastomers, fibers, and others.…”

Transparent organic materials made from copolymerization of styrene with urethane-methacrylate macromer. II. Macromer mixture system

“…1 Thermoset polymers, on the other hand, have higher heat resistance and surface hardness. 2 Therefore, one can fabricate high heat resistance and excellent surface hardness polymeric materials by preparing crosslinking polymers.…”