Sciencemadness Discussion Board

Purifying Gallium

symboom - 27-10-2011 at 17:39

so i was figuring out how purify gallium after using it to dissolve aluminum and generate a lot of hydrogen gas. but im more interested in purifying it.
i was thinking of just pulling it through filter paper while it is a liquid strange thing is as a liquid it does not pass through the paper it just sits on top as if on a solid surface. does not flatten out though it balls up the other way ive thought to filter it was buy melting it and freezing it to get rid of the aluminum hydroxide as that works it takes a lot to do to make sure it is pure
anyone else try this or know of any better filtering ways. im wandering if maybe vacuum filtering would do it i don't have a strong enough one as in its a hand powered vacuum pump.

hkparker - 27-10-2011 at 19:31

Let it sit in slightly diluted HCl solution until it balls up and no reaction is observed. The gallium will ball up and is of usable purity.

Endimion17 - 28-10-2011 at 05:38

I see nothing strange with the fact it won't pass through filter paper at usual forces. Filter papers rely on the fact that liquids wet their fibers and form a bridge between each side of it. Molten metals do not wet paper fibers and have great surface tension.

simba - 28-10-2011 at 15:43

Quote: Originally posted by hkparker  
Let it sit in slightly diluted HCl solution until it balls up and no reaction is observed. The gallium will ball up and is of usable purity.


Doesn't HCl react with gallium to form trichloride salt? I was reading a patent the other day which said it does.

When I needed to handle some gallium I used a solution of water + bisulfate, and it works fine too.
Quote: Originally posted by Endimion17  
I see nothing strange with the fact it won't pass through filter paper at usual forces. Filter papers rely on the fact that liquids wet their fibers and form a bridge between each side of it. Molten metals do not wet paper fibers and have great surface tension.


Gallium will wet paper...in non-acid medium it will wet pretty much everything.

hkparker - 28-10-2011 at 15:49

Quote: Originally posted by shivas  

Doesn't HCl react with gallium to form trichloride salt? I was reading a patent the other day which said it does.

When I needed to handle some gallium I used a solution of water + bisulfate, and it works fine too.

Gallium will wet paper...in non-acid medium it will wet pretty much everything.


It might but it is very, very slow compared to the aluminum/oxide impurities that he is trying to remove. If that other solution is more effective then by all means I would say use that.

Gallium does wet everything it is a huge pain. The reason mercury is cleaned through a filter like that is it doesn't stick to anything and is very heavy.

Endimion17 - 28-10-2011 at 17:19

Quote: Originally posted by shivas  
Gallium will wet paper...in non-acid medium it will wet pretty much everything.


No, it won't wet the paper in the true sense of wetting like water, which would allow the transfer through the paper using reasonably small amounts of the metal at 1 G.
Yes, you can smear gallium on the paper, but you can't wet it. I doubt you ever saw it penetrating the fibers and any cappilary action going on.

simba - 28-10-2011 at 18:53

Quote: Originally posted by Endimion17  
Quote: Originally posted by shivas  
Gallium will wet paper...in non-acid medium it will wet pretty much everything.


No, it won't wet the paper in the true sense of wetting like water, which would allow the transfer through the paper using reasonably small amounts of the metal at 1 G.
Yes, you can smear gallium on the paper, but you can't wet it. I doubt you ever saw it penetrating the fibers and any cappilary action going on.


Yes, I didn't actually mean 'wet'. I have done this before, gallium is like a silvery paint.

symboom - 30-10-2011 at 14:12

i notice its surface is semi solid like probably thin layer of oxide and no it wets the fingers very messy but does not defuse through paper even when i apply vacuum filtration maybe hot water will keep the from forming surface oxidation. as i did melt it on a burner. i do like the idea of using dilute hcl maybe to break it up. but my thought is the more you you use the metal and filter it the less you end up with. from the metal sticking to just about every thing i still have small pieces left in the original container it does not melt together very well if there are impurities. ive never seen mercury pass through a paper filter does any one have a video of it. to bad the stuff is a nuro-toxin and gallium is messy.

MrHomeScientist - 31-10-2011 at 08:20

Quote: Originally posted by symboom  
ive never seen mercury pass through a paper filter does any one have a video of it. to bad the stuff is a nuro-toxin and gallium is messy.


I tried this recently, and it was difficult but seemed to work reasonably well. I just made a filter paper cone and poked a tiny hole in the point with a paper clip, then poured the mercury through. That's the suggested method, but mine rapidly got clogged. Maybe my hole was too small for the dirt to pass through and thus caused blockage?

Gallium is awesome by the way, one of my favorite elements (and incidentally the first for my collection). The only bad thing about it is the damn wetting :(

[Edited on 10-31-2011 by MrHomeScientist]

symboom - 3-11-2011 at 19:19

:D finally some what good method using hot water and vinegar the acidic vinegar does not react with it but it does cause it to ball up a little.
The molten pieces clump together now before the pieces of gallium would not flow together because of to much impurities.
and now it seems like the impurities float to the surface of the metal.
also the gallium solidifies in to a crystal like structure. which i haven't been able to do since Ive had it after alloying with aluminum.
i figured that the vinegar might not react with gallium being in the same family as aluminum.
anyways tell me what you think and other maybe better methods.

[Edited on 4-11-2011 by symboom]