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Alaqua 7004 Boulevard East, Suite 28A,Guttenberg, NJ USA 07093    +(00-1) 551 482 7568   
Alaqua 7004 Boulevard East, Suite 28A,Guttenberg, NJ USA 07093    +(00-1) 551 482 7568   

Crystallizers: Specification, Design, and Methods

Date:30 November, 2021   |   No Comments   |   Posted By Team Alaquainc

A crystallizer is processing equipment used to transform wastewater into solid crystals and pure water. Crystallization, a solid-liquid separation process, forms solid crystals from a liquid solution. Crystallizers can eliminate liquid waste, achieving Zero Liquid Discharge (ZLD). So primary nucleation and secondary nucleation are the two steps in the crystallization process. Secondary nucleation is the major stage that leads to the bulk formation of crystals and is what keeps growth going.

Specifications of Crystallizers:

While the selection of crystallizers necessitates an examination of the application requirements. So a salt crystallizer, for example, treats wastewater to generate both solid salt crystals and clean water. A resin crystallizer allows flake or amorphous resin pellets to crystallize. So other crystallizers tailored to specific applications are also available.

Crystallizers made in USA can be used alone or in conjunction with other technologies like a brine concentrator or an evaporator. Steam-driven evaporators evaporate water from a solution or slurry, but the output is still liquid rather than crystal. So evaporation concentrates a product by boiling the solvent, usually water. A brine concentrator, a type of evaporator, is widely used to transform waste-saturated industrial effluent into distilled water for reuse. A typical brine concentrator can recycle 95 to 99 percent of wastewater. 

There are four types of crystallizers equipment:

  • Crystallizers for bulk solutions. While nucleation and growth take place, crystals are suspended in solution for an extended period of time.
  • Vessels for accumulating precipitation. When feed streams enter the vessel, they quickly reach high degrees of supersaturation (due to chemical reactions, drowning, or salting-out), generating enormous quantities of tiny crystals.
  • The majority of the solution or melt (usually > 90%) crystallizes in suspension or on a cooled surface. The little quantity of uncrystallized mother liquor retains impurities.
  • Melt crystallizers produce massive single crystals of great purity. Large, pure, defect-free crystals develop slowly from high-purity melts.

All of these pieces of equipment has the following features in common:

  • Crystallization is induced by creating supersaturation in this area.
  • For crystal growth, a zone is when crystals come into contact with the supersaturated solution. In certain conditions, crystals are suspended throughout the vessel by agitation; while in others, crystals occupy only a portion of the vessel, generally as a fluidized bed.

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The feed material available, the system parameters, and the customer’s product needs will all influence which crystallizer is best for a given assignment. The following are examples of common design sequences:

  • Data collecting at its most basic level
  • Careful selection of methods is essential for generating supersaturation.
  • Batch or continuous operations are available.
  • Selection of a certain piece of equipment.
  • Tests on a bench and on a small scale.
  • Full-fledged design.

Supersaturation Generation-

 Five Methods:

  • Utilizing vessel walls, internal coils, or an external heat exchanger achieves cooling. This method is employed when the solubility of the feed stream varies significantly with temperature and when the feed stream approaches saturation at a high temperature.
  • Heating the mother liquid or lowering the pressure in the vessel creates a boiling zone at the top, accomplishing evaporation. While applicable to various systems, this method consumes more energy than cooling.
  • Reaction in which input streams enter and mix, resulting in a chemical reaction that produces the product, frequently at high supersaturation levels.
  • Introducing a miscible solvent to a mixture causes drowning out, resulting in a less soluble product
  • Salting out is the process of removing a product from the solution by adding salt with a common ion. This has a lot in common with reaction crystallization.

Role of Crystallizers in Industrial Development & Manufacturing-

Process robustness regulates process productivity and profitability. Crystallization stands as one of the most widely employed processes in the chemical industry, finding extensive application in the food and pharmaceutical sectors for enhanced purification, separation, and selection of solid forms. For the creation of Active Pharmaceutical Ingredients (APIs), crystallization is the most prevalent method of forming pharmaceutical solids. So the physical form influences the quality and efficiency of pharmacological products, thus optimizing particulate qualities such as particle size and shape distributions is critical.

Many pharmaceutical medicines have poor physiochemical characteristics, such as low biological fluid solubility. To enhance the manufacturing of Active Pharmaceutical Ingredients (APIs), extensive research and development initiatives have focused on establishing a comprehensive solid-form landscape encompassing solvates, polymorphs, salts, co-crystals, and the amorphous phase.

Crystallization Methods-

Several conventional crystallization processes exist, each with its own set of advantages and disadvantages. The procedure used must be based on the qualities of the crystallizing substance.

  • Solvent Evaporation: Solvent evaporation is simple to set up, needs air-tight samples, and only a small amount of solvent to operate efficiently. 
  • Slow cooling: It necessitates solvents with low boiling points and modest solute solubility. Ensure a specific quantity of material is available.
  • Solvent/Vapour Diffusion: It works well with modest quantities of material, although it can be difficult to locate two acceptable solvents. So it is possible to “oil out.”
  • Sublimation: It isn’t the best way to make diffraction-quality crystals. Usually done at high temperatures, which causes crystals to develop too fast.


Although crystallization processes can be difficult to manage, sonocrystallization is a more recent type of crystallization that has several advantages over previous approaches. The development, growth, and collapse of bubbles cause acoustic cavitation in liquids. So the collapse of the bubble gives enough energy to speed up the nucleation process. So this produces crystallizations that are very reproducible and predictable, as well as a number of other advantages.

  • Induction times are shorter.
  • Metastable zone width (MSZW) decrease.
  • Nucleation rate has sped up.
  • Crystal growth speed has increased.
  • Minimize agglomeration as much as possible.
  • Tailor crystal size distribution to individual needs.

While crystallizers play a crucial role in recovering salts from wastewater, facilitating their reuse or sale. Crystallizers supplier in USA supplies it to be utilized by a variety of industries, including manufacturing, chemical processing, mining, petrochemical refining, and electric component manufacture.

Alaqua is a processing equipment such as the evaporator, solvent recovery, distillation, spray dryer, heat exchanger, and crystallizer supplier in USA that fulfills various industrial requirements. So we also provide troubleshooting, personnel training, installation and commissioning, retrofitting, and other services for processing equipment. Connect with us to know more!

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