Sciencemadness Discussion Board

Chemical separation challenge

symboom - 11-4-2020 at 19:55

So this fertilizer contains
Ammonium phosphate
Potassium chloride
And urea
All useful chemicals
What is the best method for separation

Sulaiman - 11-4-2020 at 21:33

Some mixed fertilizers are supplied as a mixture of individual ingredients, each in prill (small ball) form,
commonly each ingredient type is of a different colour and/or texture
and they can be physically separated by hand and eye,
... tedious but quite quick and very efficient.

unionised - 12-4-2020 at 02:44

To a fair approximation, alcohol will dissolve the urea, but leave the others behind.

There are two different ammonium phosphates.
And how practical it is to separate whichever of them you have from the KCl depends on the proportions.

Bedlasky - 12-4-2020 at 10:03

Phosphate can be separate as calcium phosphate. Then you can dissolve calcium phosphate in sulfuric acid and filtered off CaSO4. You obtain fosforic acid from which you can prepare phosphate of your desire.

You left with mixture of KCl, NH4Cl and little bit of CaCl2. If you let evaporate most of water (but not all) you obtain KCl + NH4Cl crystals. When you heat them, NH4Cl decompose.

symboom - 12-4-2020 at 21:56

Thanks to the two last posts I have separated it first the urea was removed with ethanol filtered then separated and then calcium chloride was used to precipitate calcium phosphate
With ammonium chloride and potassium chloride left I just have to decompose the ammoium chloride and crystalize the potassium chloride.

What's good about this is it's cheap 13-13-13 all purpose fertilizer and I get a bit of chemicals from the 50 pound bag

The potassium chloride I'm going to turn in to potassium chlorate
Phosphorous can be made with the calcium phosphate
And not sure what I can use ammoium chloride for yet

This is much better than buying a 50 pound bag of sodium free water softener containing potassium chloride which I don't need that much potassium chlorate

[Edited on 13-4-2020 by symboom]