Crystallization

crystallizecrystallisationcrystallizedcrystallizescrystallizerCrystallization processescrystallizingrecrystallizationcrystallisedcrystallises
Crystallization or crystallisation is the (natural or artificial) process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal.wikipedia
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Crystal

crystallinecrystalscrystalline solid
Crystallization or crystallisation is the (natural or artificial) process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal.
The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification.

Supercooling

supercooledsupercoolsupercooled water
The first is nucleation, the appearance of a crystalline phase from either a supercooled liquid or a supersaturated solvent.
A liquid crossing its standard freezing point will crystalize in the presence of a seed crystal or nucleus around which a crystal structure can form creating a solid.

Freezing

solidificationfrozenfreeze
Some of the ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas.
Most liquids freeze by crystallization, formation of crystalline solid from the uniform liquid.

Precipitation (chemistry)

precipitateprecipitationprecipitates
Some of the ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas.
Thus, it precipitates as it is formed, preferably forming pure crystals.

Crystal growth

growngrowthcrystal growing
The second step is known as crystal growth, which is the increase in the size of particles and leads to a crystal state.
Note that in a typical solidification or crystallization process, the thermodynamic driving force is dictated by the degree of supercooling.

Supersaturation

supersaturatedsupersaturateoversaturated
The first is nucleation, the appearance of a crystalline phase from either a supercooled liquid or a supersaturated solvent.
Crystallization will occur to allow the solution to reach a lower energy state.(Keep in mind that this process can be exothermic or endothermic).

Metastability

metastablemetastable stateunstable molecules
Certain polymorphs may be metastable, meaning that although it is not in thermodynamic equilibrium, it is kinetically stable and requires some input of energy to initiate a transformation to the equilibrium phase.
Extremely pure, supercooled water stays liquid below 0 °C and remains so until applied vibrations or condensing seed doping initiates crystallization centers.

Chemical engineering

chemicalchemical engineerchemical technology
In chemical engineering, crystallization occurs in a crystallizer. A crystallization process often referred to in chemical engineering is the fractional crystallization.
Unit operations (such as crystallization, filtration, drying and evaporation) are used to prepare reactants, purifying and separating its products, recycling unspent reactants, and controlling energy transfer in reactors.

Polymorphism (materials science)

polymorphpolymorphspolymorphism
Many compounds have the ability to crystallize with some having different crystal structures, a phenomenon called polymorphism.
Various conditions in the crystallisation process is the main reason responsible for the development of different polymorphic forms.

Population balance equation

population balance
The theoretical crystal size distribution can be estimated as a function of operating conditions with a fairly complicated mathematical process called population balance theory (using population balance equations).
This includes topics like crystallization, liquid-liquid extraction, gas-liquid dispersions, liquid-liquid reactions, comminution, aerosol engineering, biology (where the separate entities are cells based on their size or intracellular proteins ), polymerization, etc. Population balance equations can be said to be derived as an extension of the Smoluchowski coagulation equation which describes only the coalescence of particles.

Mother liquor

Crystals that form are then filtered and washed with a solvent in which they are not soluble, but is miscible with the mother liquor.
A mother liquor is the part of a solution that is left over after crystallization.

Protein

proteinsproteinaceousstructural proteins
However, larger biochemical particles, like proteins, are often difficult to crystallize.
In particular, globular proteins are comparatively easy to crystallize in preparation for X-ray crystallography.

Fractional crystallization (chemistry)

fractional crystallizationfractional crystallisationfractional recrystallization
A crystallization process often referred to in chemical engineering is the fractional crystallization.
It fractionates via differences in crystallization (forming of crystals).

Nucleation

nucleatenucleatingnucleated
The first is nucleation, the appearance of a crystalline phase from either a supercooled liquid or a supersaturated solvent.

Molasses

blackstrap molassesblack treaclebarrel molasses
In the sugar industry, vertical cooling crystallizers are used to exhaust the molasses in the last crystallization stage downstream of vacuum pans, prior to centrifugation.
The juice is boiled to concentrate it, promoting sugar crystallization.

Crystal habit

habitMassivetabular
Most minerals, however, do not display ideal habits due to conditions during crystallization.

Evaporator

Evaporatorsevaporator coilevaporating unit
The most common type is the forced circulation (FC) model (see evaporator).
Water can be removed from solutions in ways other than evaporation, including membrane processes, liquid-liquid extractions, crystallization, and precipitation.

Pumpable ice technology

The idea behind the second method is to create the crystallization process inside of the volume of the cooled liquid.

Evaporation

evaporateevaporatedevaporates
This division is not really clear-cut, since hybrid systems exist, where cooling is performed through evaporation, thus obtaining at the same time a concentration of the solution.

Sodium sulfate

Glauber's saltsodium sulphateNa 2 SO 4
An example of this crystallization process is the production of Glauber's salt, a crystalline form of sodium sulfate.
This takes advantage of its unusual solubility properties, and the high heat of crystallisation (78.2 kJ/mol).

Axial-flow pump

axial flow pumpaxial machinesaxial pump
A pumping device (a pump or an axial flow mixer) keeps the crystal slurry in homogeneous suspension throughout the tank, including the exchange surfaces; by controlling pump flow, control of the contact time of the crystal mass with the supersaturated solution is achieved, together with reasonable velocities at the exchange surfaces.
In the chemical industry, they are used for the circulation of large masses of liquid, such as in evaporators and crystallizers.

Recrystallization (chemistry)

recrystallizationrecrystallizedrecrystallisation
Crystallization requires an initiation step.

Single crystal

single-crystalsingle crystalsmonocrystalline
In the case of silicon and metal single crystal fabrication the techniques used involve highly controlled and therefore relatively slow crystallization.