Extract ammonium sulfate from water

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.





> 
> 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](https://en.wikipedia.org/wiki/Sea_salt).




---


**Update**


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 ;)


 1