Reducing to reclaim bismuth.

[emcelhannon]

I grow bismuth crystals to make sculpture and jewelry. Every time I melt, I lose a bit to oxygen on the surface. I've collected enough slag to prompt the question. Can I reduce this efficiently to offset my $22 per lb for the new stuff?

Thanks for considering my problem.

Ernie

[John Cuthber]

How happy are you about working with rather dangerous chemicals?

[emcelhannon]

I've got some protective gear and enough sense to play with muratic acid outside. What do you have in mind?

[John Cuthber]

I can't in all good faith recommend melting together bismuth oxide, charcoal and caustic soda unless you already have experience with that sort of thing- but it works.

 

How much of the stuff do you have?

Edited August 17, 2012 by John Cuthber

[elementcollector1]

Bismuth oxide, charcoal and NaOH? This is an interesting recipe, care to share the reaction?

[John Cuthber]

Molten NaOH is a flux (and not nice stuff)

The reaction is something like

2 Bi2O3 + 3C ---> 2Bi + 3 CO2

Followed by the reaction of the CO2 with NaOH.

I chose NaOH because it's got a low melting point.

[emcelhannon]

"I can't in all good faith recommend melting together bismuth oxide, charcoal and caustic soda unless you already have experience with that sort of thing- but it works."

I wouldn't dream of actually doing this. How hot do I need to get it?

 

I probably have 10 lbs of slag that formed on the surface of 300 degree C bismuth. If I were dumb enough to try this, I'd experiment with 1 lb at a time, outside with a fan, eye/lung protection and covered with rubber to my elbows. Pure, (.9999) bismuth costs about $22 per lb. or $48 per kg. I have the lye, and what I have to assume is Bi2O3. Can I use charcoal for grills? It's not even close to pure carbon is it? Or do I need to get the carbon for aquarium filters?

 

What could I keep in my crucible to slow down the oxidization? Is there anything I can use inside my shop for that?

Thank you for your responses.

[John Cuthber]

I did it on a scale of an ounce or so.

I'd not consider trying it on a much bigger scale but I'd probably not need to. Powdered charcoal (from any source) would do the job. Stainless steel will do as a reaction vessel.

The reason I used the caustic as a flux is that it has a low melting point.

On a bigger scale there's less need for it because the air has less chance to get to the freshly produced metal.

In any event, on the scale you are talking about the generation of carbon monoxide is likely to be an issue. Work outside or get a couple of alarms.

[emcelhannon]

Bismuth oxide, charcoal and NaOH? This is an interesting recipe, care to share the reaction?

 

It's more your name I'm replying to. I got into bismuth teaching my kid the periodic table, and collecting about 1/2 the of elements. Theo Grey's site periodictable.com was very influential, and helpful. Anyway, this is me.

https://www.etsy.com/listing/98130033/power-that-cannot-be-denied-levitation

https://www.etsy.com/listing/102844490/reserved-spirit-and-fire-beautiful

[elementcollector1]

It's more your name I'm replying to. I got into bismuth teaching my kid the periodic table, and collecting about 1/2 the of elements. Theo Grey's site periodictable.com was very influential, and helpful. Anyway, this is me.

https://www.etsy.com...nied-levitation

https://www.etsy.com...-fire-beautiful

 

Hello! Theo Gray was one of my inspirations to start an element collection too.

First off, allow me to say that those are some HUGE bismuth crystals! Beautiful, too.

Second, element collecting is a fun hobby, but it can be a dangerous one when you make the elements yourself (thermite, halogens, alkalis, transition metals, etc.) Probably worth it in the end, if you're careful. Unlike me. XD

 

Back to this bismuth isolation, would this not be possible (and somewhat preferable over molten NaOH)?

[emcelhannon]

Hello! Theo Gray was one of my inspirations to start an element collection too.

First off, allow me to say that those are some HUGE bismuth crystals! Beautiful, too.

Second, element collecting is a fun hobby, but it can be a dangerous one when you make the elements yourself (thermite, halogens, alkalis, transition metals, etc.) Probably worth it in the end, if you're careful. Unlike me. XD

 

Back to this bismuth isolation, would this not be possible (and somewhat preferable over molten NaOH)?

 

 

Thanks, im pretty invested. I saw that video, but I didnt think it would work since it's bismuth sub silicate, and I'm dueling with oxides.

Have you seen the vid where a guy reduces sodium from thermite?

[John Cuthber]

That method for bismuth sub salicylate would work with the oxides but the initial dissolving would be rather slow. Also there would be significant impurities introduced from the foil. It isn't pure aluminium.

[elementcollector1]

What of an aluminum can, then? Use the nonpainted parts and I'm fairly sure that's pure aluminum.

 

Also, I looked up an MSDS for aluminum foil, and it said it was "95% Al with (a few different impurities)" and a layer of plastic on it.

 

And yes, I did see the sodium thermite! I tried it myself, and I got a tiny sliver of shiny metal that wouldn't come off the slag.

Also, most of it seemed to be some sort of sodium oxide / hydroxide mix.

I would honestly recommend electrolysis of the molten hydroxide with carbon anodes from a welding store and a car battery, even though the molten NaOH is considerably more dangerous when you have to check on it every now and then.

 

Initial dissolving in HCl is always rather slow, unless it's a metal like magnesium or some such.

[John Cuthber]

The only practical way to get decent purity aluminium is to get scrap electrical cable from a junk yard.

You also need to consider that the powdered Bi that you get will tend to oxidise rather rapidly when you melt it.

 

You could dissolve the Bi scrap in dilute acid then electrolyse it to reclaim the metal.

[emcelhannon]

You could dissolve the Bi scrap in dilute acid then electrolyse it to reclaim the metal.

 

I like this idea. I can just keep a vat outside where i dump my scrap and keep some juice runnung through it to collect from electrolysis. Is this energy efficient? Will hydrochloric acid do?

 

Thanks so much. This thread is chock full of useful ideas!

 

E.

Edited August 27, 2012 by emcelhannon

[John Cuthber]

HCL would do, but the by-product would be chlorine which is unpopular with the neighbours.

Sulphuric would be better.

Also you need some sort of inert anode.

[emcelhannon]

.

You also need to consider that the powdered Bi that you get will tend to oxidise rather rapidly when you melt it.

 

You could dissolve the Bi scrap in dilute acid then electrolyse it to reclaim the metal.

 

 

Suppose I melt the powdered bi under charcoal, lye or argon?

[John Cuthber]

Charcoal should work.

[emcelhannon]

HCL would do, but the by-product would be chlorine which is unpopular with the neighbours.

Sulphuric would be better.

Also you need some sort of inert anode.

 

 

Neighbors aren't a problem, and muratic acid is easy to find. Still, where would I buy sulfuric? What anode would you suggest?

 

Thanks tons for your help!

E.

[elementcollector1]

Sulfuric acid can be bought as certain drain cleaners, 'pH Down', and others. It can also be made with some difficulty.

A good example of an inert anode is platinum, although carbon, lead dioxide, and MMO (Multi-Metal Oxide) have seen some use in the manufacture of perchlorates for their resistance to chlorine.

All in all, I would recommend carbon for a simple, low-voltage home setup: The best is a carbon welding rod, as pencil lead and the rods from batteries tend to have resin and other organics in them, as well as maybe forming some sort of intercalated 'graphite oxide' which further breaks down the structure until all you have left is a black sludge. There have been no reports of this with welding-grade carbon rods, however.

[emcelhannon]

Charcoal should work.

 

How hot do I need to get it? I'm trying to bond C to O, right?

[John Cuthber]

If it's hot enough to melt the bismuth that will probably do, but red hot will be quicker.

[weiming1998]

Instead of working with high temperatures, how about this:

 

1, Dissolve the bismuth slag in HCl to produce bismuth (III) chloride

2, Add pieces of aluminium to reduce the bismuth (III) chloride to the metal.

3, Wash the resulting mixed metal powder with more HCl. Bismuth only dissolves slowly in HCl when oxygen is present, while aluminium and other impurities readily dissolves, so reasonably pure bismuth powder remains.

[me_2]

Hi all,

 

came through google on this subject. I play myself a little with chemical on a lab scale, recently a lot with bismuth.

 

I've tried regaining Bi from Bi2O3 by electrolysis which works fine in that way that I can extract the Bi. The result is a sludge of Bi and when dryed a Bi powder. The remelting give me problems. When I heat the Bi powder, a great part transforms back to Bi2O3. The only solution I can think of is melting it under a inert atmosphere so Bi can't react with O2. Any other solutions ?

 

--

 

You also need to consider that the powdered Bi that you get will tend to oxidise rather rapidly when you melt it.

 

You could dissolve the Bi scrap in dilute acid then electrolyse it to reclaim the metal.

 

 

 

Suppose I melt the powdered bi under charcoal, lye or argon?

 

What do you mean with 'melting under charcoal' ?

 

Do you mean I should mix the Bi powder with charcoal and then melt it ? How do you clean up the Bi ?? I suppose there will always stay some C behind in the Bi ? Or will it float all on top ?

 

--

[emcelhannon]

Hi all,

 

came through google on this subject. I play myself a little with chemical on a lab scale, recently a lot with bismuth.

 

I've tried regaining Bi from Bi2O3 by electrolysis which works fine in that way that I can extract the Bi. The result is a sludge of Bi and when dryed a Bi powder. The remelting give me problems. When I heat the Bi powder, a great part transforms back to Bi2O3. The only solution I can think of is melting it under a inert atmosphere so Bi can't react with O2. Any other solutions ?

 

--

 

 

 

What do you mean with 'melting under charcoal' ?

 

Do you mean I should mix the Bi powder with charcoal and then melt it ? How do you clean up the Bi ?? I suppose there will always stay some C behind in the Bi ? Or will it float all on top ?

 

--

 

I've been mixing in the charcoal with scraps and oxidized bismuth, and putting an extra layer of charcoal on top. I haven't stopped to carefully weigh the results, but it seems to help. I haven't tried lye yet. Temperatures up to 700 f are easy. The oxidized metal seems to float to the top with the charcoal which is perfect since that's the combo I want. Small amounts of slag stick to the sides.