RogueRose
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Mono Ammonium Phosphate - dissolved in water - what are these different layers?
IDK why the images are showing so large, I changed the size to 1280..
The MAP (Mono Ammonium Phosphate) was dissolved in water and evaporated over a long period in a jug. There was no filtering of the product and it was
fertilizer. There were three distinct layers and I am trying to figure out what they are.
Top Layer - long needle like clearish crystals - looks kind of like ice
Middle layer - White small crystals, looks like icy snow
Bottom layer - Grey with the top layer of the grey possessing some needle like crystals and some crystals similar to the middle
layer. IDK if these grew into this layer, pushing through or if it is from the substance itself. It looks kind of like dried mud.
    
[Edited on 21-6-2016 by RogueRose]
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woelen
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Is this made from fertilizer grade material?
I think that you dissolved a lot of this material in water. All kinds of insoluble impurities settled at the bottom. At the top, near the surface of
the liquid, you had quite pure NH4H2PO4 dissolved in water. At the middle, there might have been some very small solid particles which did not easily
settle to the bottom and at the bottom you had a lot of insoluble crud, forming a layer of gray stuff. If you allowed this to dry, then it is easy to
understand that the bottom layer contains a lot of gray crud, mixed with NH4H2PO4 and at the top you have quite pure nice crystals. The middle layer
will have some impurities, the amount of impurities getting larger the more you go to the bottom.
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RogueRose
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Thanks for the reply. There was about 500g dissolved and I tried to filter it but it was really messy and difficult. I was wondering if the phosphate
was the grey stuff and if the crystals was the ammonia.
Is there a way to test if the grey material has phosphate? I thought it may have been bone meal or something.
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DraconicAcid
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The ammonium is not separable from the phosphate by crystallization, because they are part of the same compound, NH4H2PO4. Just like you can't let
salt water evaporate, and expect separate crystals of sodium and of chlorine.
Dissolve the stuff in water, let it settle overnight, and carefully decant the upper part through a filter. That will give you a purer solution of
ammonium dihydrogen phosphate.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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