Author Topic: Red P from Phosphoric acid?  (Read 9496 times)

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UTFSE

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Re: Red P from Phosphoric acid?
« Reply #40 on: November 02, 2001, 06:58:00 PM »
h-p how stable is P vapour? seems like the solid phase is the only "dangerous" form - relative to fire/explosion.

I have viewed these fraction columns in my search for - well most anything to do with hydrocarbons. Wish you could get a graphic (or a link to a graphic) for your alluded to design.

Silver solder might work - my mig welder would surely work.



just glad to bee here-----he he he

Rhodium

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Re: Red P from Phosphoric acid?
« Reply #41 on: November 02, 2001, 07:02:00 PM »
P vapor can definitely ignite explosively in the presence of oxygen.

foxy2

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Re: Red P from Phosphoric acid?
« Reply #42 on: November 02, 2001, 07:54:00 PM »
Here is how to clean your equipment(safely).  If I was dreaming MA then I might just get rid of all the white phos this way, turn it right into a much safer chemical.

Big bucket of conc. KOH solution(NaOH should work to, maybee), make sure you have excess hydroxide.

P4 + 4KOH + 4H2O --> 2H2 + 4KH2PO2

Hmmm I'll bet some bee's could find a use for POTASSIUM HYPOPHOSPHITE  :)

If you don't have excess then this happens, nasty and deadly phosphine is formed

P4 + 3KOH + 3H2O -> PH3 + 3KH2PO2



Do Your Part To Win The War

halfapint

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Re: Red P from Phosphoric acid?
« Reply #43 on: November 27, 2001, 09:23:00 AM »
Returning again unto our first ways and so retracing our paths, let's get back to the retort type apparatus. This seems more likely to get built, and to have fewer places to go wrong.

The retort arm descends at a steep angle to its bend, a reinforced elbow joint resting on, or cast into, a block. This block might have provisions for moderate auxiliary heating, if it is thought to be necessary. From the elbow stretches a long pipe of large diameter (put your fist in it) which descends at a shallow angle into a trough of water until its far end is just submerged.

You do not want to have the end of your condenser pipe in deep water. You want to show minimal back pressure to any impulse pressure. Burning solids have granulations and hot spots, they burn sometimes irregularly. Since you can't tell how strong a pressure wave might bee, you don't want to trap it. You want to let it go. You want it to bubble out and flare freely in the air, as far may bee from your main apparatus, and from human noses. So put the end of the pipe in shallow water, not in deep water.

I have also changed my opinion about the water temperature. I no longer think ice water would be ideal starting coolant for this reaction. You don't want to end up with solid phosphorus in your pipe, in fact you want it liquid all the time it is in your pipe, so it will all flow out into the water. A phosphorus blockage is one of the prime things you want to avoid. Using these considerations, I might want to put warm water in my trough to start with. Steamy warm, maybe 50 or 60 degrees, to make sure that condenser pipe holds runny liquid phosphorus with no tendency to congeal. Again, though, as the reaction progressed, I might wash out the old water with new cooler water, at a flow rate which does not threaten to splash out any phosphorus.

The main differences I see now, with the way I pictured it at first, is the use of the elbow block, and starting with warm water not ice water. Plus the decision, that if anything pushes too hard, to let it go. You are polluting a bit, as anything that bubbles from the end of the pipe gets carried away by the breeze into the natural environment, but if you can ensure people and large mammals are not in the way, you cause no mortal harm. This way I think we can run, still a dangerous run, but I think we've worked the suicidal aspects out of it.

turning science fact into <<science fiction>>