# silver/alumina mix



## golddie (Sep 25, 2009)

Hi Everyone

To refine silver/alumina mix 
I will tell you what I would do and if I am wrong please correct me.

Option1
I would 
I would add hydrochloric acid and that would dissolve the aluminum
Then the silver will be there in pieces

Option 2
I would Dissolve in nitric then the aluminum will not dissolve so i will pick out the aluminum and then add salt to the mixture to claim the silver

I hope am right with these 
Thanks


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## Oz (Sep 25, 2009)

Keep nitric away from aluminum first off. As to the HCl that depends greatly on if you have alumina as your title says, or aluminum like soda cans.


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## butcher (Sep 25, 2009)

aluminum can make a jelly like mess.

try some expierimenting, small batchs, different concentrations, it can help.

maybe even expieriment with caustic sodium hydroxide, small tests.


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## golddie (Sep 25, 2009)

they are not aluminum cans


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## butcher (Sep 25, 2009)

not cans, or beer cans
I was trying to say, aluminum could (can)make a slimy substance.how much aluminum is in the acid will make a difference.
aluminum is a bit difficult, of coarse this has been my expierience with it.
aluminum and Hydrochloric acid = slimmy goo


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## Oz (Sep 26, 2009)

That’s my fault Butcher as I mentioned soda cans in my first reply trying to clarify between aluminum and alumina. I mentioned to keep nitric away from aluminum but not the why of it (I was pressed for time) but I did wish to save him from a non-filterable solution. Thanks for fleshing that part out a bit.

The key thing here is that one must understand that alumina and aluminum are not the same thing, although the base element is the same. Processing is dependant upon the difference. If it is indeed aluminum metal I would tend to agree with Butcher that NaOH is the way to go. It is also wise advice Butcher gave that if you have any decent quantity or are unsure of what its contents are to proceed with small samples.

Would not the cat guys love it if nitric would dissolve alumina?


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## goldsilverpro (Sep 26, 2009)

golddie,

You say both alumina and aluminum. Which is it? Also, is it the solid type of alumina used in IC packages or the form used in catalysts?


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## golddie (Sep 26, 2009)

Hi Gsp



> The grease is is a combination of silver and alumina with the binder stripped off using MEK and IPA, then washed with water.



I dont actually have this item 
I am trying to help someone


Would 
thermal refining work in this case


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## peter i (Sep 27, 2009)

Be honest!

If you give all the facts, you can have a good answer rather than guesswork.


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## Lou (Sep 27, 2009)

In any case, I would boil in concentrated lye to dissolve away the material. Silver does not dissolve in bases, but aluminum does (much preferred than all acids save HF).


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## golddie (Sep 27, 2009)

I saw this question being asked on the internet and i dont go there all the time.

They were recommending thermal refining whatever that is
This is all the information they had

Its doesn't have anything to do with honesty


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## golddie (Sep 27, 2009)

> Silver does not dissolve in bases, but aluminum does (much preferred than all acids save HF).


Can someone explain that 
what is HF
I am inquiring about this because I am curious its for the sake of learning something 
I read the article and there is no more info to help with what the product is
Thanks


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## Oz (Sep 27, 2009)

HF=Hydrofluoric acid

It is very nasty stuff that will even eat your lab glass. Do not use it without proper instruction and equipment.


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