【Haichuan Teahouse】Why is seawater salty, but it becomes fresh when it freezes?

Take out the phase diagram and take a look – see what the salt content of the crystal is at the freezing temperature

It is said that there is a difference between rapid crystallization and slow crystallization

As soon as the weather cools down, potassium chloride, which is sensitive to cold, goes into a dormant state: lol

The solubility of potassium chloride is related to temperature

“28 grams at 0 degrees Celsius, 31.2 grams at 10 degrees Celsius, 34.2 grams at 20 degrees Celsius, 37.32 grams at 30 degrees Celsius, 40.1 grams at 40 degrees Celsius, 45.8 grams at 60 degrees Celsius, and 45.8 grams at 70 degrees Celsius.

Sea ice refers to saltwater ice that forms directly from the freezing of seawater, and it also includes continental glaciers that enter the ocean (icebergs and ice islands), as well as river ice and lake ice. Saltwater ice is a mixture composed of solid ice and brine (including certain salt crystals), with a salinity that is 2–10‰ lower than that of seawater. Its physical properties (such as density, specific heat, heat of solution, latent heat of vaporization, thermal conductivity, and expansivity) differ from those of freshwater ice. When seawater freezes, it is the water that freezes, pushing the salt out of it; some of the salt that does not have time to flow away remains trapped in the spaces between the ice crystals in the form of brine, creating \"salt bubbles\". Furthermore, when seawater freezes, gases that do not have time to escape are trapped between the ice crystals, forming \"bubbles\". Therefore, sea ice is actually a mixture of freshwater ice crystals, brine, and bubbles.

The freezing method can now be used to solve the problem of seawater desalination; P; P; P

You know, when I saw this news, it reminded me of that story about a wealthy Middle Eastern man who planned to transport Antarctic sea ice to the Middle East in order to obtain fresh water

A long time ago, I was sucking on a piece of ice cream with white sugar in it; because I kept sucking on it, by the end almost no sweetness was left in the ice cream. I’m thinking that this could turn into a great invention: by freezing substances that might be damaged by high temperatures and then using vacuum under conditions corresponding to their melting point, it’s possible to **increase the concentration of solutes**. This might be the discovery of an important industrial method; P

It is used in metal smelting and purification, such as remelting and crystallization, under low temperature gradients, and for the purification of precious metals