Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: desalination by freezing

Learn more physics!

Most recent answer: 03/17/2017
Q:
I just read your answers for salt water freezing vs fresh water freezing (from 2011). I also just watched the movie "the day after tomorrow". They talk about the Antarctica ice and how they are able to look back in time for the weather. A thought occurred to me, can freezing salt water also be used to desalinate the water? Meaning, will the frozen water on top of the salt water be salt free /drinkable?stay curious,Steve
- steve (age 42)
roselle, il, usa
A:

Yes, ice crystals that form from salt water contain almost no salt. So long as the freezing is slow, the salt will be excluded, but in fast freezing it can get trapped in little pockets between the ice crystals. There have been proposals to use icebergs to supply fresh water to desert countries, but I don't think that those have been cost-effective yet.

Here's a popular article describing some of those attempts:

 https://www.theatlantic.com/technology/archive/2011/08/the-many-failures-and-few-successes-of-zany-iceberg-towing-schemes/243364/ https://www.theatlantic.com/technology/archive/2011/08/the-many-failures-and-few-successes-of-zany-iceberg-towing-schemes/243364/

Mike W.


(published on 03/17/2017)

Follow-up on this answer.