SaltMaker ChilledCrys

Eutectic chilled crystallization for cost-effective minimal and zero liquid discharge

To produce solids, chilled crystallizers need to overcome a much lower thermodynamic barrier than evaporators. For very specific solution chemistries, chilled crystallization is a highly competitive option for zero liquid discharge.

Eutectic Chilled Crystallization

Eutectic Chilled Crystallization (ECC) cools a fluid, forcing salts to precipitate. Although it works only for specific salt-ion pairs (e.g. Na2SO4), it leverages the efficiency of Carnot cycles (1 unit of power equates to 3 units of heat), making it a great fit for some projects.


If a salt-ion pair in a concentrated brine has a steep temperature-solubility relationship (e.g. Na2SO4), then cooling will form salt precipitants. The salt can be separated out while the brine is recycled for further processing. Some salts produce hydrated crystals (e.g. Na2SO4⋅10H2O) which remove water during the crystallization process.


Saltworks holds proprietary technology to complete the chilled crystallization process in a closed loop. We package this with intelligent controls in our SaltMaker ChilledCrys system, which continually removes water and salt, enabling cost and energy efficient ZLD.

Photo of a full-scale SaltMaker ChilledCrys Plant
A full-scale SaltMaker ChilledCrys Plant
Chart showing temperature-solubility curves for sodium sulfate solids produced by SaltMaker ChilledCrys
Chart showing temperature-solubility curves for sodium sulfate solids produced by SaltMaker ChilledCrys

When to Use SaltMaker ChilledCrys? 

Chilled crystallization may be a viable option for zero liquid discharge (ZLD) or minimal liquid discharge (MLD)—if your solution consists predominantly (>90%) of the following ion pairs:

  • Sodium or potassium sulfate
  • Sodium or ammonium carbonate/bicarbonate

For example, cooling a solution of 200,000 mg/L sodium sulfate from 20°C to 10°C will precipitate over half of the sodium sulfate as a solid, which is then easy to separate. The result is a solution with a final concentration of 100,000 mg/L sodium sulfate and the emergence of ~50% of the salt as a solid. Every solution is different, and our engineers can complete an assessment for yours. 

ECC ≠ Freeze Crystallization

SaltMaker ChilledCrys uses chilled crystallization, which should not be confused with its cousin: freeze crystallization (FC). FC was worked on extensively in the 1950s and 60s.

  • In FC, small ice particles (known as frazil) are formed. Salt is rejected from the ice during freezing. The ice is then separated, washed, and thawed leaving pure water behind.
  • In ECC, as used by SaltMaker ChilledCrys, rather than forming ice to remove water from the system, we use industrialized desalination technology, and then form specific salt-ion pairs when chilling, which are separated from the solution.

Contact us today with your water chemistry and treatment goals. Our experts can help you determine if SaltMaker ChilledCrys is the right fit for your MLD or ZLD project.

Process flow diagram of a SaltMaker ChilledCrys system
Process flow diagram of a SaltMaker ChilledCrys system

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