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Author: Subject: Preparation of elemental phosphorus
peach
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[*] posted on 2-10-2010 at 14:04


First of all, nice work checking the slag. Maybe you could post some out to people with more things to test for precisely what's in it.

The boria thing may not be a simple case of the dry reagent costs. If it can be run at a much lower temperature, as strepta suggests, that alone may outweigh the extra cost by simplifying what's needed. For instance, it could be heated with nichrome wire perhaps, on a desktop, as opposed to needing a furnace outside.

I have the things to build a pretty darn funky furnace, but I'd still prefer a cute desktop thing that I can easily pack up, unpack and control without worrying about the fire, blower, exhaust and things like that.

If mixing is an issue, it could always take a whiz in the coffee grinder as he suggests. Or ball mill it. If it's going molten under the heat however, I'm not sure it needs to be so finely divided. Black powder does because it doesn't go through a liquid state, and solid / solid reactions ALWAYS benefit from finer grains and better mixing if increasing the reaction RATE is an issue.

Sometimes, of coarse, bigger grains and poorer mixing help by slowing things down to make them more controllable.

[Edited on 2-10-2010 by peach]




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Rogeryermaw
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[*] posted on 2-10-2010 at 15:36


thinking back to the first successful run i would say the AlP formation is certain. remember how i said that it popped in my hand as i was trying to clean out the reactor? with audible report and a visible flash? i quenched it after the run thus getting the inside of the reactor wet.

as far as what strepta said about the phosphine self igniting i don't think it does that without a small formation of di-phosphine as well. the di-phosphine ignites and then takes the phosphine with it. and drying the reactants helped to keep the spontaneous formation of phosphine low as on that first run i noted much fire bursting from the reactor and on successive runs it was little to zero since i began pre-drying the reactants.

if anyone wants to test this slag i'd be happy to send a sample. not sure if it should be labeled hazardous and what that would mean for shipping but if i crush it and send it i suppose it could be treated as sand




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[*] posted on 3-10-2010 at 07:24


Quote: Originally posted by Rogeryermaw  
thinking back to the first successful run i would say the AlP formation is certain. remember how i said that it popped in my hand as i was trying to clean out the reactor? with audible report and a visible flash? i quenched it after the run thus getting the inside of the reactor wet.



Hmmm... IIRW we attributed that to moisture in the mix, it doesn't necessarily point to AlP...

As regards analysis of the slag, the more I think about that, the more I think it's pro's job, because you've (and Strepta/Magpie) probably created a new mineral, a sodium silicato-aluminato-phosphato thingy-me-jibs! Grinding it down to extreme fineness (elutriating, even...) would then allow elemental analysis with X-ray Fluorescence (XRF) but that doesn't tell you in what molecular form the P is present...

Bar that, high temperature calcining in air would probably get rid of elemental P and phosphines (to P2O5) and convert any AlP to an aluminium phosphate.

The calcinate could then be treated with concentrated, hot H2SO4: the phosphates would then dissolve as H3PO4. After filtering/decanting/centrifuging/whatever the clear solution obtained would then contain the soluble PO4 (3-), quantity to be determined with various applicable methods...

Few of us here are equipped to pull that off...

In short, since as determining the composition of the slag, as part of an accurate yield determination, is probably outside the realm of our possibilities (I'm just throwing this is in as a teaser for Peach ;-) ), the best way forward would be to improve the collector. Strictly logically speaking...


[Edited on 3-10-2010 by blogfast25]
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[*] posted on 3-10-2010 at 07:26


Quote: Originally posted by peach  

The boria thing may not be a simple case of the dry reagent costs. If it can be run at a much lower temperature, as strepta suggests, that alone may outweigh the extra cost by simplifying what's needed. For instance, it could be heated with nichrome wire perhaps, on a desktop, as opposed to needing a furnace outside.


[Edited on 2-10-2010 by peach]


What makes you think boria would allow to run at lower temps? IMHO the rate determining step is the dissociation of P2O5 and that's VERY temperature dependent...
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Rogeryermaw
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[*] posted on 3-10-2010 at 09:15


the first things i'm going to try are stoich amounts of reactants and i have a few ideas for improving collector design. i think just by giving the vapor more time to reach the water and allowing it to cool a bit before it gets there will help control loss to air. this could significantly increase yield. my observation after running the experiment at night(the darkness allowed me to see the burning P vapor escaping from the lid) leads me to believe this is one of the areas of the system that can be improved upon the most.

on a positive note i did something for my safety and health today. my wife is bringing me a case of nitrile gloves home from work tonight and i picked up some neoprene gauntlets(almost elbow length). i also picked up a face shield and have a set of z-87.1 goggles.
next i'm going order one of those soviet era gas masks with replaceable cartridges...hopefully i can find cartridges that handle solvent and acid fumes...after that all i need (besides fume cabinet) is a good apron(and a lab coat to look the part;))





[Edited on 3-10-2010 by Rogeryermaw]




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[*] posted on 3-10-2010 at 23:10


I should girl it up on the sewing machine and make you an aramid & nomex onepiecey, that'd make a god damn awesome SM picture. :D

Before going to crystallography and such, it'd probably be worth looking for the phosphane again. Although, in terms of waiting for it to get through the post, the potential complaining that may occur if they manage to break the packet and spill the contents (no matter how well packed) and the time it'd take me to check it, it may be worth having a fiddle with the collector and reactants first, then upgrade to international collaboration if that stumbles as well.

If it has gone to some metal phosphorous compound, I wonder if there'd be an easy method for reoxidizing it to elemental phosphorus, without ending up with oxides or a gigantic bill. It's used as a phosphorus source in semiconductor labs, like Silane is for Silicon. I think they get the silicon back out on it's own with high temperatures under inert gas.

The boria thing, I have zero evidence of blogfast, just that Strepta mentioned it. In my rapid reading, I thought he was saying it starts producing at a lower temperature, but he does say it MELTS at 450C (which of coarse, isn't running and you're likely right about the P2O5 disassociation). What temperature did you have to run it up to Strepta?

If it melts and takes the phosphorus source into solution with it at 450C, I wonder if some form of electrolysis could then be used.




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[*] posted on 4-10-2010 at 08:54


Quote: Originally posted by peach  


The boria thing, I have zero evidence of blogfast, just that Strepta mentioned it. In my rapid reading, I thought he was saying it starts producing at a lower temperature, but he does say it MELTS at 450C (which of coarse, isn't running and you're likely right about the P2O5 disassociation). What temperature did you have to run it up to Strepta?



I mentioned boria as it melts considerably lower than silica yet produced only marginal improvement in yield. Make of that what you will. If sodium metaborate is one of the reaction products as not_important suggested, it does melt a bit lower (966C) than sodium silicate. In a setup like Roger's that may mean the post reaction slag could be kept molten as he is adding considerable heat input both during and after the reaction. I heated the slag with a meker burner before the reaction to initiate and after the reaction to drive the P out of the slag.

I measured the reaction temperature only one time using a thermocouple probe. Reaction onset was about 500C with a subsequent rise in temperature to ~ 700C. This was with silica. The reaction with pyrotechnic Al is self-sustaining once initiated.
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[*] posted on 4-10-2010 at 09:16


Quote: Originally posted by peach  
If it has gone to some metal phosphorous compound, I wonder if there'd be an easy method for reoxidizing it to elemental phosphorus, without ending up with oxides or a gigantic bill. It's used as a phosphorus source in semiconductor labs, like Silane is for Silicon. I think they get the silicon back out on it's own with high temperatures under inert gas.
Silane spontaneously dissociates at moderately high temperature (420° C according to Wikipedia), unlike phosphine.
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[*] posted on 4-10-2010 at 09:24


@peach: Nice to see that you're using Ubuntu as well....

@Rogermeryaw: How go you heat the stuff ? Propane ? How hot does it get or don't you have a pyrometer / thermocouple ?

[Edited on 2010-10-4 by metalresearcher]
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[*] posted on 4-10-2010 at 10:03


no unfortunately i haven't added that bit of equipment to my cache yet. my temps are estimated by the color charts available from metal working sites such as this: http://www.blksmth.com/heat_colors.htm
my furnace is wood fired with forced air. by the charts available i am reaching temps of at least 1150Celsius. note that the reaction and boiling of the melt in my experiments occurs at lower temp than this but that is how high i have pushed it. with less discretion it would certainly get hotter.



[Edited on 4-10-2010 by Rogeryermaw]




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[*] posted on 4-10-2010 at 10:38


Quote: Originally posted by Rogeryermaw  
the first things i'm going to try are stoich amounts of reactants and i have a few ideas for improving collector design. i think just by giving the vapor more time to reach the water and allowing it to cool a bit before it gets there will help control loss to air. this could significantly increase yield. my observation after running the experiment at night(the darkness allowed me to see the burning P vapor escaping from the lid) leads me to believe this is one of the areas of the system that can be improved upon the most.
[Edited on 3-10-2010 by Rogeryermaw]


You could add a spray nozzle to the top of the can that would spray the vapors. Might prevent some losses. The way I imagined it the spay nozzel is hooked up to an aqquarium pump and submerged into an ice bath next to the receiving vessle. A small hole or tube is placed into the side of the vessle to allow for drainage/circulation. Glass wool or something else could be used to prevent solids escaping from the receiving vessel. I havent been able to decide if the tube releasing the P vapor should be submerged, bearly submerged, or unsubmerged since I decided to use an ice bath. Maybe the tube releasing the P vapor should be inserted at an angle so the spray will not directly hit the tube and will instead be directed towards the spot where the bubbles will surface. Inert gas could prevent the vapers from igniting and could be used to pass the vapors through another colder collection vessle increasing yeilds.
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[*] posted on 4-10-2010 at 10:51


if delivery of vaporized phosphorus is not submerged you will certainly have to use inert gas or it will all be lost to atmosphere. there is no delay time to the ignition of phosphorus in vapor or even liquid form. if it is warm enough to be in a liquid state it will ignite instantaneously. as far as a spray nozzle i would fear pressurization creating an unsafe condition though i won't discount its possible value without trying it. beware the ignition of liquid phosphorus. you don't want to be close to it. it snaps and pops throwing flaming globs of phosphorus a good distance and the burns it can cause will turn necrotic. they are very slow healing. also cooling your collector may be advantageous but i would refrain from using ice. if your product solidifies in a closed system it will greatly frustrate your attempts to recover it. remember that phosphorus is deadly toxic and the less handling the better. i look forward to your experimentation results.



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[*] posted on 4-10-2010 at 11:21


Quote: Originally posted by Rogeryermaw  
no unfortunately i haven't added that bit of equipment to my cache yet. my temps are estimated by the color charts available from metal working sites such as this: http://www.blksmth.com/heat_colors.htm


True, temp colors depend on the ambient lighting. I did this with melting copper in bright sunlight, it looked like melting tin:

<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/GROogYAShj4?fs=1&amp;hl=en_GB"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/GROogYAShj4?fs=1&amp;hl=en_GB" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>
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[*] posted on 4-10-2010 at 11:24


So roger you are saying if you run this open system reactor vessel on the left and collector in water on the right, there will be enough remaining o2 in the tube to cause the liquid phase to self ignite? Ok so perhaps it does. At some point the 92 will be consumed and then things will be jolly good no?
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[*] posted on 4-10-2010 at 11:41


@metalresearcher. based on that my furnace may be significantly hotter. most of my work has been done in full sunlight.

@thereelstory mainly i was referring to his idea about using ice in the collector. if the output of the tube is exposed to air at all you can kiss the bulk of you phosphorus goodbye.




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[*] posted on 6-10-2010 at 08:06


Stick a bit of copper in there roger and you'll be able to see if it passes the melting point, without having to buy a thermocouple for a rough idea.

You must have a bit of copper lying around.

If not, I know where you can get some... :P:D




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[*] posted on 6-10-2010 at 08:14


already done that. i had a copper bottomed pot i set over the furnace to see what color the steel would get to...it's not copper bottomed anymore...;)



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[*] posted on 6-10-2010 at 08:16


Quote: Originally posted by peach  
I should girl it up on the sewing machine and make you an aramid & nomex onepiecey, that'd make a god damn awesome SM picture. :D



don't you mean S&M picture?:P




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[*] posted on 6-10-2010 at 09:34


After a few experiments I have decided that silicon dioxides main purpous in the reaction is to give the mix a thicker consistancy which slows down the reaction.
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[*] posted on 6-10-2010 at 12:30


Quote: Originally posted by aax  
After a few experiments I have decided that silicon dioxides main purpous in the reaction is to give the mix a thicker consistancy which slows down the reaction.


Are you possibly a troll, aax? If you've actually carried out any experiments and have drawn some conclusions based on them, then please report. Otherwise, please kindly eff off.
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[*] posted on 6-10-2010 at 19:10


what are you melting the copper with in that video metalresearcher?



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[*] posted on 8-10-2010 at 13:01


Quote: Originally posted by blogfast25  
Quote: Originally posted by aax  
After a few experiments I have decided that silicon dioxides main purpous in the reaction is to give the mix a thicker consistancy which slows down the reaction.


Are you possibly a troll, aax? If you've actually carried out any experiments and have drawn some conclusions based on them, then please report. Otherwise, please kindly eff off.


Your weird...

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[*] posted on 8-10-2010 at 13:38


I read that P4 is soluble in benzene at high tempature. I also found out that if you were to boil the phosphorus in benzene at 200 degrees celcius under increased pressure the P4 would change to red phosphorus. UV rays speed up the transformation. The alternative to boiling it in solvent under increased pressure is to leave it out in the sun or under a tanning lamp. If your using UV rays alone you would want to increase the surface area. I'm sure the best way to increase surface area is to dissolve it into benzene.... That sounds like the most surface area possible to me.... Put it in benzene then leave it in the sun or under a tanning lamp for a month and then boil off the benzene... I haven't been able to find any information on the solubility of RED P4 in benzene. If Red P4 is insoluble then it should precipitate right out but thats only if it will even convert to red p while in solvent.


[Edited on 8-10-2010 by aax]
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[*] posted on 8-10-2010 at 13:54


Quote: Originally posted by Rogeryermaw  
if delivery of vaporized phosphorus is not submerged you will certainly have to use inert gas or it will all be lost to atmosphere. there is no delay time to the ignition of phosphorus in vapor or even liquid form. if it is warm enough to be in a liquid state it will ignite instantaneously. as far as a spray nozzle i would fear pressurization creating an unsafe condition though i won't discount its possible value without trying it. beware the ignition of liquid phosphorus. you don't want to be close to it. it snaps and pops throwing flaming globs of phosphorus a good distance and the burns it can cause will turn necrotic. they are very slow healing. also cooling your collector may be advantageous but i would refrain from using ice. if your product solidifies in a closed system it will greatly frustrate your attempts to recover it. remember that phosphorus is deadly toxic and the less handling the better. i look forward to your experimentation results.


Hey I had an idea... What if you coated the inside of the piping with mineral oil? The P should slide right down into the water. Another idea I had is to increase the diameter of the tube going into the water and coat the inside with mineral oil then submerg it into ice water which is in an ice salt bath... This should cool the tube up to a high enough point that the P4 will condence into a solid mass before it reaches the water.
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[*] posted on 9-10-2010 at 06:35


Not sure about the red P stuff, but with the pipe idea, a serious problem with that may be it trying to condense inside the pipe too readily, blocking it.

Even if the inside is coated with oil, there's a good chance the oil won't be enough, it will run off, heat will get to it or the P will simply catch on the none mirror smooth insides. Then all the blockage problems start.

A safer method, that'd probably yield even better, would be to submerge the pipe as normal, but then have metal wool or something similar (broken glass?) over the surface of the oil. The vapours will be more likely to catch on it, but the chances of it entirely blocking would be lower.

You would then have to wash the P back off with a suitable solvent though.

However, I doubt much of this specularizing is worth a pinch of silica until the main problem causer has been found in the first place. And I expect Roger is off having a break for a bit.

[Edited on 9-10-2010 by peach]




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