Sciencemadness Discussion Board

Make Phosphorus from Ca phosphate and Mg powder ?

metalresearcher - 31-1-2022 at 08:20

The topic about the guy "Kobold vor NH4" who got burns on his arm with an attempt making phosphorus using phosphate with magnesium powder triggered me to verify whether it is possible to make P4 using phosphate and Mg powder. I have Ca phosphate and Mg powder.

Reaction which I expect: Ca3(PO4)2 + 5 Mg => 3 CaO + 5 MgO
310 121
The ratio should be 310 : 121. So I mixed 3.1 g phosphate with 1.2g Mg powder and set fire to about 1g of the mixture with a burner. It reacted slowly and not sustainable (I had to keep the burner to heat the mixture). Indeed the bright yellow flames billowing white P2O5 smoke appeared.
Then I put another gram in a test tube with a stopper and a glass tube into water. Just above the surface to avoid suckback.

When heating, red color appeared in the bottom of the test tube and smoke (P4 vapor + P2O5 ?) appeared in the tube and got into the water.
Then I added the rest of the mixture and it reacted again upon heating.

The reddish color appears to be not only red glow, but also the red calcium color.

Conclusion: P4 can be made this way with a more robust distillation kit (e.g. stainless steel tubes) and no violent reactions took place. I used gloves as I was prepared for a similar event as "Kobold vor NH4" experienced, but it did not happen.

Video: https://www.metallab.net/jwplayer/video.php?f=/forums/Calciu...

papaya - 31-1-2022 at 12:13

Look what I've found !
Sodium tripolyphosphate + MgAL:
https://www.youtube.com/watch?v=kCA7Ne24cm4
Also many different things are possible like with borax: https://www.youtube.com/watch?v=3IAv6Ohjuh8
Carbonates :https://www.youtube.com/watch?v=3n8Cgl_deEM
As one can see under right conditions all of them can react self-sustainingly, when thermodynamics are favorable of coarse.



simply RED - 1-2-2022 at 01:34

Be careful with those things, accidental phosphide and phosphine poisoning may occur.

Kobold vor NH4 - 1-2-2022 at 03:58

Hmm I speculate that it did not react as mine did because the Mg had to replace the Ca from the molecule, maybe that is less exothermic compared to the magnesium already being attached and ready to "fly off" once the other oxygen is removed. Maybe. I should calculate it to make sure though.

zed - 15-4-2022 at 02:07

This is unlikely to produce elemental Phosphorus.

But, if it actually does.... Please post in the Phosphorus Link, in General Chemistry.

Kobold vor NH4 - 15-4-2022 at 04:42

Quote: Originally posted by zed  
This is unlikely to produce elemental Phosphorus.


Why do you say that zed? I may try a variation of metalresearcher's experiment, A.K.A using Ca3(PO4)2 instead of decomposing H2NH4PO4. Maybe even a metal that is lower on the reactivity series might work better, such as Cu or Fe phosphate with aluminium powder

BJ68 - 29-6-2022 at 03:10

Other way:

" A. R o s s e 1 und L. F r an k: Darstellung von Phosphor
aus den Phosphaten der Alkalien und alkalischen Erden mittels
Aluminium als Reductionsmittel und Einwirkung des Aluminiums auf Sulfate und Chloride"

https://zenodo.org/record/1425728/files/article.pdf

Attention: If there is calcium sulfate in the mixture, it will explode....

Bj68

PirateDocBrown - 29-6-2022 at 15:38

The more hydrogen, the more phosphine. Dry your reagents out.