Author Topic: isolating phosphoric acid  (Read 2610 times)

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fnord

  • Guest
isolating phosphoric acid
« on: June 10, 2004, 04:18:00 PM »
just found a rust remover in my local marine store that says it contains phosphoric acid and was wondering how to isolate just the phosphoric acid, would fractinal distalation work? what othe methods might be usefull i know the phosphoric acid frezes at below 20 but the rest of the mixture freezes too any ideas?


barkingburro

  • Guest
phosphoric acid is useless
« Reply #1 on: June 10, 2004, 05:12:00 PM »
can't do much of anything with it. you are prolly thinking of phosphoNic. if you want phosphoric you can get it by the gallon at most hardware stores as a surface cleaner.

Rhodium

  • Guest
Corrosive acids are not nice at 280°C...
« Reply #2 on: June 10, 2004, 06:08:00 PM »
would fractinal distalation work?

Look up the boiling point of phosphoric acid and see if you might want to rethink that strategy.


ApprenticeCook

  • Guest
phosphoric is at building supply companies.
« Reply #3 on: June 10, 2004, 09:58:00 PM »
phosphoric is at building supply companies.

H3PO4 - d213oC
so in other words if you bring it to that temp you will decompose the acid, hence screw it. Thats before it boils too.


Nicodem

  • Guest
Boil water off
« Reply #4 on: June 11, 2004, 03:33:00 AM »
You can simply concentrate the rust remover by boiling off water. Measure the density to get the concentration.
But where I live it does not contain much H3PO4 (about 10%) so its not really a good source.


ApprenticeCook

  • Guest
thats assuming it only contains phosphoric...
« Reply #5 on: June 11, 2004, 09:21:00 AM »
thats assuming it only contains phosphoric acid and water though.


Nicodem

  • Guest
H3PO4 with water and MeOH
« Reply #6 on: June 11, 2004, 11:35:00 AM »
Well, mine also contained some methanol but that is nothing bad. I did fuck up once though, when I used ceramic boiling chips that dissolved almost completely and made the H3PO4 dirty and useless. It's incredible but hot H3PO4 can dissolve the silicates!

BTW, H3PO4 is also good for making polyphosphoric acid.


r2e3

  • Guest
anything below pH3
« Reply #7 on: June 12, 2004, 06:37:00 AM »
well - thats for silica gel

barkingburro

  • Guest
ok but i still fail to see the usage
« Reply #8 on: June 12, 2004, 09:14:00 AM »
of this endeavor. if purely for shits and giggles, cool. but if your purpose is to obtain phosphoric, why this method? it is STRAIGHT OVER THE COUNTER in usuable forms. it's farking everywhere. and also what use is polyphosphoric? i UTSFE'd it and found lots of ways to make it, no real simple uses for it

r2e3

  • Guest
yeah
« Reply #9 on: July 10, 2004, 06:13:00 AM »
just check you local hydroponics shop and you'll be laughing