Sciencemadness Discussion Board

Ammonia from aluminium/magnesium + water?

Antiswat - 25-10-2020 at 12:55

so, as im casting an alloy i was having some issues with some of the oxides i had to remove from the surface starting to burn, i dumped some of it in a stainless steel cup with cold water
however, the cup was rather clean (had just used it couple days before for melting aluminium), but this cup started generating fumes of ammonia, the solution smelled like maybe 5% ammonia solution
while it was still hot it was making barely flammable gas bubbles, which would surely not be hydrogen

my only lead on this is that aluminium with nitrate and alkali hydroxide can form ammonia, but the only alkali present would be MgO or Al2O3- which isnt really able to do the same reaction as CaO- right? anyhow the magnesium can still react with water to make hydrogen and then react with a present nitrate- but theres no nitrate, both the magnesium and aluminium was as rather pure rods, rather clean pieces
is ammonium salts somehow added to magnesium or aluminium?? could the magnesium have reacted with nitrogen in the air, formed magnesium nitride and then with magnesium reacting with water making NH3 or is this too far fetched?
im almost sure i can remember some ammonia being formed when dunking MgAl in water many years back so i really dont think it has anything to do with the stainless cup itself

Antigua - 25-10-2020 at 13:03

When magnesium is exposed to high temperatures in air, magnesium nitride forms. This compound is hydrolised to magnesium hydroxide with release of ammonia (be it by water or atmospheric moisture).

Antiswat - 25-10-2020 at 13:08

is there any way you can isolate magnesium nitride? if just a spoonful of slag is able to form 200mL of 5% ammonia there must be quite some magnesium nitride in the slag

Antigua - 25-10-2020 at 13:21

I haven't done any research on that topic, but possibly something like NurdRage did with sodium and magnesium - warming it up in 1,4-dioxane or some other solvent that is between those two's densities to isolate it. Other than that not sure, usually it's prepared quantitively in order to omit the isolation problems.

Antiswat - 25-10-2020 at 13:23

aha, luckily its not very useful except for making ammonia, very cool. im sure efficiency could be upped a load by vigoriously stirring the mix in pure nitrogen atmosphere.

TriiodideFrog - 30-10-2020 at 23:31

There is a disgusting way to make ammonia hydroxide. Boil your urine down until there are only solids left. Then add concentrated sodium hydroxide to the mixture in a flask and then connect a latex tube to another flask filled with some water. the latex tube should be hovering above the water's surface so there is no backflow.

Alkoholvergiftung - 31-10-2020 at 07:01

When Iron I oxide get oxidized on moist air it forms ammonia too. one way to synthesis it.

Fyndium - 31-10-2020 at 07:58

Most here probably know that the most economical way to produce ammonia is to boil hydroxide with urea. During test run I produced almost a liter of SG 0.888 ammonia solution in couple of hours. I suppose this thread was about ammonia as a side product.

Antiswat - 3-11-2020 at 10:37

if youre going for hydroxide, why not go with calcium hydroxide? i know that urine on its own can break down into fairly high concentration of ammonia (i'd shoot at least 15%) during my attempts of pouring jugs of piss on hay, slight offtopic, as for making fertilizer using urine i spoke to one other guy who idealized rather than having air just come into a pile of hay with urine on it, just have a big collection of piss and pump air into that with a simple aquarium bubbler, having the whole thing in liquid form would save you for a lot of trouble with the whole process

is there any cool way to seperate urea without boiling down the piss?

gerrockium - 3-11-2020 at 18:09

Quote: Originally posted by Antiswat  

is there any cool way to seperate urea without boiling down the piss?

by forward osmosis, until crystalization of the urine salts... think so

this article did it but in order to make a concentrated urea solution

[Edited on 4-11-2020 by gerrockium]