What is the best method to extract ammoniumsulfate from water?

The assignment is as follows:

Manure is being processed and the product left is a mixture between water and ammonium sulfate, transporting the mixture costs a lot of money. So we only want the ammonium sulfate.

What is the best method to do this on a big scale? Evaporation isn't a good option since it costs too much energy to heat the big amounts of water.

  • $\begingroup$ Depends on if you want the sulfate or ammonium or both. $\endgroup$ – Zhe Jan 30 '17 at 23:25
  • $\begingroup$ You would probably have to add a lot of grain alcohol to precipitate the ammonium sulfate out (ammonium sulfate is insoluble in ethanol), and recovering the alcohol for re-use wouldn't be free either. Does this route look too costly? $\endgroup$ – airhuff Jan 31 '17 at 1:44

Evaporation isn't a good option since it costs too much energy to heat the big amounts of water.

Is it? I've seen prices around USD 130-150 per ton (minimum order of 25 tons) for ammonium sulfate with a purity around 99%. You might want to calculate the costs to operate a production plant using natural gas (or other fuels) for evaporation yourself.

There is however a different energy source that you might want to take into consideration: the sun.

Evaporation of water from solutions of sodium chloride in open ponds by solar heating alone has a long tradition in the production of sodium chloride in the form of sea salt.


Ammonium sulfate will not evaporate from the open ponds. At temperatures between 235-280 °C, it will start to decompose.

However, if surface temperatures reach that level under irradiation with unconcentrated sunlight, the fate of the ammonium sulfate is the least of your worries ;)

  • $\begingroup$ Thanks for your quick answer, I have a question, as soon as the evaporation in an open pond starts, won't the ammonium sulfate start to evaporate too? $\endgroup$ – Karim Leurink Jan 31 '17 at 8:47
  • $\begingroup$ @KarimLeurink I've updated my answer. $\endgroup$ – Klaus-Dieter Warzecha Jan 31 '17 at 9:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.