Sciencemadness Discussion Board

Fire extinguisher dust - MAP & AmmSulf - any use when mixed?

RogueRose - 17-10-2015 at 15:33

I had some extinguishers which had lost charge and have about 10lbs of powder in it, I cut it open and dumped it into a bag. The ingredients are MonoAmmonium Phosphate, Mica, Ammonium Sulphate, Talc, Nuisance Dust, Irritant, HMIS1-0-0

Here are the MSDS (Don't know which one it is, both for same model)
MSDS MAP/AmmSulf equal mix
55-65% MAP
30-40% Amm Sulf
+ Mica, Clay, Amorphous Silica, Dye

MSDS 2 - High MAP

85-95% MAP
<5% Amm Sulf
+ Mica, Clay, Amorphous Silica, Dye

Is there anything that I can do with this stuff or is it not worth working with. I'd like to make phosphoric acid if that is possible or if possible seperate it out into MAP and Amm Sulf.

Any ideas here?

Sulaiman - 18-10-2015 at 00:46

both MAP and ammonium sulphate are water soluble to similar degrees,
good as a fertiliser, not helpful for separation.

MAP decomposes to ammonia (gas) and polyphosphoric acid above 125C
and ammonium sulphate is stable up to its melting point of 250C
So I might try heating the powder until no more ammonia fumes released
then dissolve the product in water to get a solution of ammonium sulphate in phosphoric acid.
(you could dissolve the ammonia gas in water to make a little ammonia solution)
Since phosphoric acid is more soluble than ammonium sulphate maybe the ammonium sulphate could be crystalised out ?

Hopefully you will get clearer info. when others criticise my post :D

unionised - 18-10-2015 at 01:46

Fertiliser looks like a reasonable use for the sulphate rich stuff- as log as the land has enough potash or you can supply that as well.

For the stuff that's high in MAP you could recrystallise it and have a clean supply of mono ammonium phosphate- the impurities listed won't dissolve in water (though you might get some odd exchange reactions with mica).

j_sum1 - 18-10-2015 at 02:06

You could simply use it as a source of ammonia. No harm in that.