Three routes to a single salt, and we have run all three
Salt separation and crystallization is where a ZLD plant either produces a product or a hazardous waste. There are three technical routes to get there. The right one comes out of your water, not out of a catalog.
What is salt separation and crystallization?
Salt separation and crystallization is the stage that splits the dissolved salts in a brine and crystallizes them individually, instead of drying everything into one mixed solid.
In evaporation and crystallization there are three technical routes to that split: nanofiltration separation, thermal separation and freeze separation.
JINGYU has delivered all three in projects it has built. That matters, because a contractor who owns one route will recommend it regardless of your water.
One route is not better. One route is better for you.
A supplier with one separation route will always find a reason your water suits it.
The three routes differ in capital cost, energy demand, process complexity and how well they tolerate a feed that moves. Those differences are real, and they point in opposite directions.
So the answer to which route is best depends on your ion balance, your energy price and what your buyer accepts. We can give that answer without bias, because all three are in our portfolio.
The three routes
Nanofiltration separation uses membrane selectivity to separate the divalent salts, producing a precise split. Thermal separation crystallizes sulfate hot and chloride cold, with a hot mother liquor loop between them. The two salts are produced together.
Freeze separation inverts that temperature logic. Conventional salt crystallizes at normal temperature and the sulfate at low, driven by a chilled mother liquor circuit. The result is a high-purity split.
Nanofiltration, thermal and freeze separation, all running in plants JINGYU has built and, in several cases, still operates.
That is what allows the route to be chosen from your water rather than from what we happen to sell.
Nanofiltration or thermal: how the choice is made
The two routes we deploy most often suit opposite kinds of plant. Neither is better in the abstract.
| Nanofiltration separation | Thermal separation | |
|---|---|---|
| Suits | Producers with variable water quality, many discharge points and complex operating conditions | Stable water quality: mine water, demineralization plant brine, cooling blowdown, single continuous discharge points |
| Process chain | Longer, with higher system complexity | Simpler and shorter |
| Energy | Higher operating cost | Lower energy demand |
| Capital | Slightly higher investment | Lower investment |
| Feed variation | Strong tolerance of swings in quality | Strong tolerance within its design window |
| Typical products | Anhydrous sodium sulfate and sodium chloride, dried and packaged separately | Sodium sulfate crystallized hot, sodium chloride after flash evaporation |
Freeze separation is the third route, used where a low-temperature driving force delivers the purity an off-taker requires. All three run in plants we have built.
Where it is applied
Coal and fine chemicals
Complex, variable brines with several discharge points. The nanofiltration route usually earns its extra complexity here.
Mine water and demineralization brine
Stable, continuous streams. Thermal separation gives the same product for less energy and less capital.
High-specification off-take
Where the salt has a named buyer with a tight specification. Purity rather than capital cost sets the route.
SERECS sits at the end of the train, after organic purification. What it produces is decided by how clean the brine arrives, so the two are engineered together.
Frequently asked questions
What is salt separation and crystallization?
It is the stage that splits the salts dissolved in a brine and crystallizes them individually. Each comes out as a single-species product rather than a mixed solid with no market.
What are the three routes?
Nanofiltration separation, using membrane selectivity on the divalent salts. Thermal separation, crystallizing sulfate hot and chloride cold with a hot mother liquor loop. Freeze separation, using a chilled mother liquor circuit for a high-purity split.
How is the route chosen?
From the feed chemistry, the stability of the water, the energy price on site and the specification your off-taker requires. A variable feed with many discharge points suits nanofiltration. A stable single discharge point suits thermal.
Has JINGYU actually built all three?
Yes. All three routes have been delivered in projects we have built. That is why we can recommend one without a commercial reason to prefer it.
What purity is achieved?
Sodium sulfate at 99.0% or better and sodium chloride at 97.5% or better, both against Chinese national standards. The potassium salts are produced to their own standards.
What if the brine is not clean enough?
Then the crystals are stained regardless of the separation route. Organic purification comes first for that reason. No crystallization route compensates for skipping it.
Send us your ion balance
Start here
The route your brine suits is already fixed by its chemistry. Send the analysis. We will tell you which of the three fits, and what each costs to build and to run.
Useful to include
- Brine flow and TDS
- Full ion balance, especially chloride and sulfate
- How stable the feed is, and how many discharge points
- Steam and power prices on site
- The product specification your off-taker requires
Contact us directly
- info@jing-yu.com
- Phone
- +86 21 6593 0816
- Office hours
- Monday to Friday, 9:00 to 18:00 Shanghai time (GMT+8)