Sciencemadness Discussion Board

Ammonia salt precipitation

thehexlibrary - 26-7-2019 at 13:01

Hi guys. I have a plethora of ammonia solutions of varying concentration. Instead of disposal I was wondering if you knew of any chemical I could add to precipitate the ammonia in a salt form.
Copper sulfate comes to mind but it forms more of complex. And HCl I’ve only had good success with using gas forms of ammonia and hcl to make ammonium chloride. Is there any liquid I can add to make ammonia salts hella easy?

Boffis - 27-7-2019 at 02:15

Citric acid --> diammonium hydrogen citrate
Oxalic acid --> diammonium oxalate
dilute sulphuric acid --> ammonium sulphate
Sulphamic acid (lime descaler in some countries) -->

Acetic acid is difficult because the acetate is insanely soluble and difficult to dry once crystallized.

Lots more possibilities depending on the acids you have!

happyfooddance - 27-7-2019 at 15:18

The only thing insoluble I can think of is NI3 :)

But that isn't practical.

I store larger quantities ammonia as NH4Cl. If you have big stainless steel pot for evaporation and a freezer for precipitation, you can probably make quick work of what you've got (within reasonable limits, but several kilograms is not much problem). I would do the neutralizing in something plastic or glass, and leave a slight excess of NH3. Otherwise you will damage your pot.