Sciencemadness Discussion Board

filtering ammonia gas

Fluorite - 13-1-2021 at 15:16

I did something really stupid two months ago, I mixed calcium hydroxide and ammonium nitrate to make ammonia gas and bubble it through deionized water so I can make concentrated ammonia solution, well I messed up by adding loTS of water to the mixture and now I have a full 5L HDPE bottle with calcium nitrate ammonium hydroxide and some sodium polysulfides :(
I wanted to try again by bubbling carbon dioxide and precipitate CaCO3 to get my 3Kg ammonium nitrate again and concentrate it by boiling the water but I nothing happened!
What can I do? now I wanna boil the solution to get my ammonia gas and filter it through cotton or idk so I can bubble pure ammonia but what can I use to filter the gas? Is cotton perfect for removing ALL of the aerosols /mists/sprays?
Oh btw I got my ammonium nitrate by giving my friend my DSLR and he broke it so no I can't get more

BromicAcid - 13-1-2021 at 16:12

How much carbon dioxide did you charge? It can sometimes be difficult to get into solution depending on the bubble size. You've got all the hydroxide that you need to neutralize it's gonna take quite a bit (solubility in water though is a bit low so there is that). What is the pH of the solution? Assuming polysulfides are form whatever fertilizer you procured one of the reagents from though it was not mentioned, is this a solid residue, how much? You've made a concoction here, has it been open to the air or sealed? Your plan seems decent but not sure on your follow through.

macckone - 14-1-2021 at 11:41

bubbling carbon dioxide is less than optimal.
If you have an old coke or pepsi bottle, put the solution in and pressurize it with CO2.

Fery - 14-1-2021 at 13:17

I know CaCl2 forms a complex with ammonia, isn't it possible with Ca(NO3)2 too? Maybe increased T releases ammonia from the complex or is it not enough so you were unable to obtain ammonia gas from your reaction mixture? Or was it caused only by excess of water?
I understand how cheap is technical CaO / Ca(OH)2 which could be bought in 25 kg packages in a shop specialized for building industry. But it dissolves slowly. I would prefer NaOH, but this my advice is too late and it is somewhat out of topic, your actual goal is to recover NH4NO3. Maybe for very large quantities of ammonia I would use CaO / Ca(OH)2 in the generator. Did anyone here try ammonia generator with CaO/Ca(OH)2 and with NaOH so can compare these two ways and tell practical results instead of my theoretical thoughts?

Fluorite - 15-1-2021 at 08:48

i guess ill buy a pressure cooker and boil the solution till dryness
does hydrogen sulfide stay or should i add CuSO4? i just want pure ammonia gas

Fluorite - 30-1-2021 at 14:45

Can someone please tell me why tf when I bubble ammonia I get always a turbid solution!? I used a Polypropylene syringe as a suck-back trap and I'm sure it's not the problem for the tube idk if it reacts with the ammonia

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Fluorite - 30-1-2021 at 14:48

Also! I added some NaOH to the calcium nitrate to remove any traces of Ammonium carbonate but the calcium hydroxide redissolve when I shake the flask! Is Calcium hydroxide soluble in ammonia?

Fluorite - 31-1-2021 at 14:17

I tried the same reaction again and used cotton to filter water vapors and ammonia but I still get a turbid solution! What material is this tube made of? Because it's really cheap, and if it does react with ammonia to make a turbid solution does this hydrolyze to something like ethylene glycol? Really hard to remove? Because when I filtered my concentrated ammonia through syringe with cotton I got pretty clear solution

Fyndium - 1-2-2021 at 05:09

My cheapo transparent tubes are apparently made from PVC and the other one from polyurethane. At least the other one form an opaque white layer within them when used with ammonia. This could produce something of this matter.

Actually I generated ammonia just a month ago and I used the new tubes which are PVC and they are unaffected by it. So it's PUR that is corroding with ammonia. Apparently it also is not compatible with water, but fuel oils only.

EDIT3: Polyurethane does not seem to like nitrogen dioxide either. I vented it through one and it turned yellowish opaque and it stinks like hell. I threw the tube away. PVC tube on the other hand has been holding very well against NO and NO2, even when wet, it's still like new after washing.

[Edited on 1-2-2021 by Fyndium]