kristalizacij

Kristalizacij, often translated as crystallization, is the process by which a solid crystalline phase forms from a system that is supersaturated or overheated. Crystals develop via nucleation, where a small stable cluster forms, followed by crystal growth as molecules arrange into an ordered lattice. Crystallization can occur from a solution, a melt, or, less commonly, from a gas phase.

The driving force is supersaturation, the condition in which the solute concentration exceeds its equilibrium solubility. Nucleation can be primary (without pre-existing crystals) or secondary (on the surface of existing crystals). Growth depends on temperature, cooling rate, solvent choice, impurities, additives, agitation, and seeds. Controlling these factors determines crystal size, habit (shape), and purity. Impurities may incorporate into the lattice or remain at grain boundaries, influencing properties and polymorphism.

Applications include purification and isolation of chemical compounds (notably pharmaceuticals), production of materials with defined optical or electronic properties, and roles in food and chemical processing. Crystallization also presents challenges such as polymorphism, hydrate or solvate formation, agglomeration, and Ostwald ripening, which can affect stability and performance.

Characterization uses X-ray diffraction, calorimetry, microscopy, and spectroscopy to assess structure, purity, and particle size distribution. Industrial crystallization often employs specialized crystallizers, precise temperature control, solvent and anti-solvent strategies, and seed-assisted protocols to achieve targeted outcomes.