# Reversing an Alloy
**URL:** https://boards.straightdope.com/t/reversing-an-alloy/685524
**Category:** Factual Questions
**Created:** [April 7, 2014, 3:05am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524 "2014-04-07T03:05:34Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@Deflagration](https://boards.straightdope.com/u/Deflagration)
#### Post date: [April 7, 2014, 3:05am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/1 "2014-04-07T03:05:34Z")
Is it possible to convert and alloy back into it’s component metals?
Could you get the Copper and Tin out of Bronze or the Copper and Zinc from Brass?
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [April 7, 2014, 3:13am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/2 "2014-04-07T03:13:58Z")
Sure.
It’s called “refining.”
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### Author:  [@friedo](https://boards.straightdope.com/u/friedo)
#### Post date: [April 7, 2014, 3:22am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/3 "2014-04-07T03:22:16Z")
I imagine you could do it with a really, really hot centrifuge.
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### Author:  [@california\_jobcase](https://boards.straightdope.com/u/california_jobcase)
#### Post date: [April 7, 2014, 4:16am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/4 "2014-04-07T04:16:57Z")
Metals have different boiling points. Fractional distillation is possible. For instance, mercury can be boiled out of silver fillings to reclaim the silver. A similar technique is used to mine gold and silver in some places- the mercury alloys the precious metal and is then boiled off. People have died from this, however. Also, different metals react differently to different reactants such as acids. One metal can be removed from the other by reacting it with the correct acid. I’m pretty sure there are other ways.
Here’s an article on how to get the gold out of jewelry- [http://www.ehow.com/how\_8633520\_melt-gold-jewelry-separate-alloy.html](http://www.ehow.com/how_8633520_melt-gold-jewelry-separate-alloy.html)
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### Author:  [@bizzwire](https://boards.straightdope.com/u/bizzwire)
#### Post date: [April 7, 2014, 5:46am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/5 "2014-04-07T05:46:04Z")
> [@california\_jobcase](#):
>
> Metals have different boiling points. Fractional distillation is possible. For instance, mercury can be boiled out of silver fillings to reclaim the silver. A similar technique is used to mine gold and silver in some places- the mercury alloys the precious metal and is then boiled off. People have died from this, however. Also, different metals react differently to different reactants such as acids. One metal can be removed from the other by reacting it with the correct acid. I’m pretty sure there are other ways.
> Here’s an article on how to get the gold out of jewelry- [How to Melt Gold With a Propane Torch | ehow](http://www.ehow.com/how_8633520_melt-gold-jewelry-separate-alloy.html)
Wow, that was really bad. I particularly liked where they instruct you to add boiling water to a mixture of nitric and hydrochloric acids. Great way to get a face full of boiling aqua regia
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### Author:  [@si\_blakely](https://boards.straightdope.com/u/si_blakely)
#### Post date: [April 7, 2014, 6:32am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/6 "2014-04-07T06:32:06Z")
As noted, in general it isn’t easy. Fractional distillation needs a lot of heat to boil metal, and probably an inert atmosphere to do it in.
Chemical methods are better, but for most alloys (like brass/bronze) you need strong acid to dissolve it initially, then some chemical trickery to precipitate the various metal salts to separate them, then some equally strong reducing agents to get your metal back.
Another approach would be using electrochemistry - you might not even need a strong solvent, just the correct electrolyte and voltage. You could probably just extract the copper and leave a crumbling rod of tin or zinc. It would be how I would approach the problem.
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### Author:  [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)
#### Post date: [April 7, 2014, 6:48am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/7 "2014-04-07T06:48:25Z")
> [@friedo](#):
>
> I imagine you could do it with a really, really hot centrifuge.
In fact, you can go even further and use this method to separate isotopes of the same metal. It’s one of the ways they extracted U-235 to build the atomic bomb.
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### Author:  [@Darth\_Panda](https://boards.straightdope.com/u/Darth_Panda)
#### Post date: [April 7, 2014, 7:14am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/8 "2014-04-07T07:14:55Z")
> [@bizzwire](#):
>
> Wow, that was really bad. I particularly liked where they instruct you to add boiling water to a mixture of nitric and hydrochloric acids. Great way to get a face full of boiling aqua regia
After your done throwing boiling water into hydrochloric acid, get out your blowtorch and crucible. Because, you know, most people have those lying around.
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### Author:  [@friedo](https://boards.straightdope.com/u/friedo)
#### Post date: [April 7, 2014, 8:11am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/9 "2014-04-07T08:11:06Z")
> [@Little\_Nemo](#):
>
> In fact, you can go even further and use this method to separate isotopes of the same metal. It’s one of the ways they extracted U-235 to build the atomic bomb.
Although they don’t use much heat to do that. They use a chemical process to turn the uranium ore into uranium hexafluoride gas and the centrifuge then separates out the isotopes from the gas. Then another chemical process to turn it back into metal.
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### Author:  [@am77494](https://boards.straightdope.com/u/am77494)
#### Post date: [April 7, 2014, 8:25pm UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/10 "2014-04-07T20:25:41Z")
There is no single method that is effective for all alloys. Usually fractional distillation under reduced pressure (vacuum) is used.
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### Author:  [@si\_blakely](https://boards.straightdope.com/u/si_blakely)
#### Post date: [April 7, 2014, 10:07pm UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/11 "2014-04-07T22:07:29Z")
> [@friedo](#):
>
> Although they don’t use much heat to do that. They use a chemical process to turn the uranium ore into uranium hexafluoride gas and the centrifuge then separates out the isotopes from the gas. Then another chemical process to turn it back into metal.
They did do direct ionised mass separation as well (the [calutron](http://en.wikipedia.org/wiki/Calutron)). It isn’t used any more, as Uranium Hexaflouride is marginally easier to work with than ionised uranium metal.
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### Author:  [@am77494](https://boards.straightdope.com/u/am77494)
#### Post date: [April 8, 2014, 12:52am UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/12 "2014-04-08T00:52:07Z")
Like I remarked earlier, although all the above methods maybe suitable for many metal separation - different methods are economical / applicable for different metals.
Even for metal isotope separation, the fluoride route is not universal. For example : for Lithium isotope separation , the amalgam method or the vacuum distillation method is used.
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### Author:  [@bizzwire](https://boards.straightdope.com/u/bizzwire)
#### Post date: [April 8, 2014, 5:45pm UTC](https://boards.straightdope.com/t/reversing-an-alloy/685524/13 "2014-04-08T17:45:36Z")
> [@friedo](#):
>
> Although they don’t use much heat to do that. They use a chemical process to turn the uranium ore into uranium hexafluoride gas and the centrifuge then separates out the isotopes from the gas. Then another chemical process to turn it back into metal.
Interesting factoid: During the Manhattan project, Lesly Groves wasn’t sure which process was better; gaseous diffusion (as you described), or preparative mass spectrometry. So he tried both. The mass specs required miles of wire for the electromagnets. As copper was scarce, Groves pulled all the silver bullion from the US Mint in San Francisco, and had it pulled into wire. After the completion of the project, it was all returned.
/end, cool story, bro