Sciencemadness Discussion Board

Ferrophosphorus General

VSEPR_VOID - 8-6-2018 at 15:32

In the previous thread, (http://www.sciencemadness.org/talk/viewthread.php?tid=83382), it was confirmed by myself and (http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?...) that the brackets used to hold magnets in conventional hard drives are not mu-metal, which is mostly nickel, but primarily iron. Branching from this field of ferrous experimentation I am not setting out to try and extract elemental phosphorus from an alloy containing ~71% iron, ~26% phosphorus, and the rest silicon by mass. I have 1 kilogram of this alloy.

Notes: Phosphorus reacts with nitric acid to form phosphoric acid so it may not be used. Well phosphorus can be prepared from phosphoric acid, it is very complex and required great temperatures.

I already placed 3.8g of the alloy in a beaker with about 60ml of concentrated hydrochloric acid and could see no reaction at room temperature. The solution was slightly green but this is most likely due to the regular color of the pool acid.

In once thread a user suggested passing chlorine over ferrophosphorus to yield iron and phosphorus chlorides which could be purified with distillation. This however has the problem of requiring chlorine gas in large volumes and equipment for the reaction that is resistant to high temperatures and chlorine.


tetraiodide - 8-6-2018 at 16:16

Not only that, but several phosphorous chlorides are listed as chemical weapons, and I would personally like to avoid that if it were me. Have you considered electrolysis? Also one more thing is if it's an alloy, and you remove one component, what remains, I would think, is very finely devided, and depending on the allotrope that could make pyrophoric/explosive so just somthing is keep in mind. Also I know most people have the gear to do it but if you could melt the iron distillation would be possible, but at that point you may as well just go get some calcium phosphate and charcoal from the garden depot. And forget the iron all together.

VSEPR_VOID - 8-6-2018 at 16:58

I like the idea of electrolysis. The resulting iron oxide could be washed away with hydrochloric acid to leave behind fine phosphorus (I would assume red considering its the most stable allotrope).

I do not have the equipment for high temperature distillation on that scale.

The alloy is in the form of large chunks/crystals which resemble to be meteorites.

wg48 - 9-6-2018 at 00:08

Just in case you don't know: from wiki on iron phosphide: "Iron phosphide reacts with moisture and acids producing phosphine (PH3), a toxic and pyrophoric gas:

If your ferrophosphorous is brittle you could try crushing it to get a better reaction with acid but that will probably just make more phosphine faster.

fusso - 9-6-2018 at 01:51

Is the ferrophosphorus simply a mixture of Fe & P atoms or the P exist as phosphide ions?
Can P exist as amorphous like carbon?

Fulmen - 9-6-2018 at 02:12

From what I can find it's in the form of phosphides.

unionised - 9-6-2018 at 03:08

Quote: Originally posted by tetraiodide  
Not only that, but several phosphorous chlorides are listed as chemical weapons, and I would personally like to avoid that if it were me. .

I don't think they are listed as weapons, but as weapons precursors.
(They are still pretty nasty things to play with)


Iodination of ferrophosphorus might prove interesting.
PI3 would convert alcohols to iodides (as far as I can tell, the presence of FeI2 wouldn't make much difference)

VSEPR_VOID - 9-6-2018 at 05:00

Quote: Originally posted by wg48  
Just in case you don't know: from wiki on iron phosphide: "Iron phosphide reacts with moisture and acids producing phosphine (PH3), a toxic and pyrophoric gas:

If your ferrophosphorous is brittle you could try crushing it to get a better reaction with acid but that will probably just make more phosphine faster.


I have observed no pyrophoric gasses being evolved when I treated a sample with HCl(aq), HCl(aq) + Peroxide, or when heated.

Further more it does not resemble iron phosphide, but is extremely metallic.

The alloy is resistant to acid. I found it shares this in common with nickel-phosphorus: "High-phosphorus electroless nickel offers high corrosion resistance, making it ideal for industry standards requiring protection from highly corrosive acidic environments such as oil drilling and coal mining. With microhardness ranging up to 600 VPN, this type ensures very little surface porosity where pit-free plating is required and is not prone to staining. Deposits are non-magnetic when phosphorus content is greater than 11.2%"

Source: https://en.wikipedia.org/wiki/Electroless_nickel_plating



[Edited on 9-6-2018 by VSEPR_VOID]

wg48 - 9-6-2018 at 12:06

Quote: Originally posted by VSEPR_VOID  


I have observed no pyrophoric gasses being evolved when I treated a sample with HCl(aq), HCl(aq) + Peroxide, or when heated.

Further more it does not resemble iron phosphide, but is extremely metallic.



I guess your pieces dissolves slowly or very slowly. A powder may be very much faster. Also H2O2 may oxidise phosphine.

Your ferrophosphorous is probably a solid solution or mixture of iron and iron phosphide/s (FeP,Fe2P, Fe3P). Below is a pic of Fe2P. Its looks metallic.
Fe2p.jpg - 98kB

woelen - 10-6-2018 at 12:47

There are two types of phosphides.

One type has phosphide ions and has well-defined stoichiometry, with phosphorus in oxidation state -3, and reacts easily with acids. Examples are Zn3P2, Ca3P2, AlP, Mg3P2. With acid these give nearly pure PH3 and they react easily. Some of these even react slowly with water!

The other type is very inert and can have a range of stoichiometries, e.g. Fe2P ... Fe3P, Cu3P, NiP2, and everything inbetween. The oxidation state of the phosphorus is not well-defined in these cases. These compounds usually are inert and hardly react with acids. I myself have nickel phosphide, which also looks quite metallic and I did not find anything which reacts with this at room temperature.
Many non-metal elements form such very inert compounds with transition metals, while forming very reactive and well-defined compounds with Ca, Mg, Zn. Other ones are Si, B, N, C, S.

unionised - 10-6-2018 at 13:16

On a related note, does ferrophosphorus react with sulphur?