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Author: Subject: Preparation of elemental phosphorus
clearly_not_atara
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[*] posted on 11-5-2017 at 11:02


Quote:
If you had more controlled heating would that help


I don't think so... the observations indicate a self-sustaining exothermic reaction. The best you can do is calculate the yield, both heat and volume of gas from the ideal gas law, and use those estimates to make sure your setup can contain it. You can probably slow the reaction down a little by adding an inert "solvent" such as sodium bromide which will neither be oxidized nor reduced but absorbs heat.

Also if you dissolve the CO2 in the water the P4 will be less able to escape because there will be less gas to carry it; only thing is, I'm pretty sure the gas it CO, not CO2, but I could be wrong on this point.

CO2 can be scrubbed by using alkali, weak alkali being preferable to prevent the production of phosphine. Ethylenediamine, ethanolamine, sodium phenolate, etc are applicable.
CO on the other hand might be scrubbed by iron (II) salts or something, I'm not sure.

Possibly using a metal carbide could reduce gas production while still producing a "useful" amount of CO/CO2 evolution.
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Magpie
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[*] posted on 11-5-2017 at 11:51


Commercial furnaces use coke (mostly carbon) rather than coal. Use of coal could produce all kinds of by-products like coal gas, etc. Coal gas is flammable. I suggest replacing the coal with carbon.

What exactly was your charge composition, including quantities?

[Edited on 11-5-2017 by Magpie]




The single most important condition for a successful synthesis is good mixing - Nicodem
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NeonPulse
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[*] posted on 16-6-2017 at 23:05



Been quite busy the past couple of weekends trying to get some P4 in OK yield. finally i had some success! after using the small scale method devised by strepta i found the product was hard to recover and not enough. there had to be a better way. it has taken me quite some time to read this thread in it's entirety but the knowledge discovered has been vital to success. using my gas powered forge i heated up the classic mixture of NaPO3, SiO2 and dark Al powder plus a little NaCl flux as suggested several pages back. Also using a variation of the steel can retort Magpie was using for a while was a great idea. previously i had tried a retort made from welded steel tube and plumbing bits but this failed. my forge was actually too hot and melted holes in the steel. it easily pushes 1200C when it is warmed up. figuring that a brute force heating is not needed nor was the thick steel tube setup i opted to go with the steel 500ml paint can. it is good to have it finally working but i wish the yields were better. i did another run today with the retort exit tube deeper in the water and also a cone of steel mesh around it to try to break up the bubbles a bit better. the results were better and there seemed to be bits of P4 caught in the mesh, however i pushed the limits of the retorts capacity and had it breach. next i will line one with refractory of some sort.
Pretty keen to try other methods. i have a 500ml bottle of 85% phosphoric acid i bought over a year ago which i hav barely used 10mls of. also have a bunch of mono ammonium phosphate.
maybe a carbon based reduction in the near future once i make a better setup. I also have everything I need to build an electric furnace including Hi temp fire bricks, kaowool, Kanthal elements, PID and SSR, thermocouple and steel angle. I just need to find the time to put it together.
Here's a couple of videos:

Attempt by strepta's method: https://www.youtube.com/watch?v=Xljfwz1UMWE
a successful run: https://www.youtube.com/watch?v=mhFyVDBmDVk

And a couple of pics :


IMG_3549.JPG - 170kBIMG_3577.JPG - 1.6MB




Where there is a will
there is a way.

Like many of us i also do Youtube.... AllCheMystery!
https://www.youtube.com/channel/UCWbbidIY4v57uczsl0Fgv7w?vie... Fixed link. You can see it now!
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