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Metal country of origin

  • 1.  Metal country of origin

    E Virginia Chapter Adm
    Posted 03-04-2021 15:46
    I have some aluminum samples (various alloys e.g. 6061, 7075, etc.) and I am trying to determine the country of origin.  Are there any ways to trace aluminum to specific ore deposits or identify it based on manufacturing processes?

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    David Sapiro
    Engineer
    King George VA
    dosapiro@gmail.com
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  • 2.  RE: Metal country of origin

    Posted 03-05-2021 09:18
    So this is a slightly tangential answer but I think the utility of this pursuit depends on what you're trying to use that material for. At least in the places I've worked, if your material doesn't have paperwork telling you where it's from (along with all the other details like the specification it was ordered to, QC test results, etc.), it's a doorstop and nothing more. So the most you'd be able to do with it is melt it down, sell it for scrap for someone else to melt down, or put it towards a low-criticality application where properties and traceability aren't as important (perhaps your company has a division that makes Hot Wheels cars). This may be in the cards for your 6061 but I'm sure it's not for your 7075.

    That said, if you plan on remelting it, then it will be USA material, regardless of where your melt scrap originally came from. I had an interesting conversation about this subject at a previous job working at a subsea equipment fabricator - in the subsea world, it's common practice to put aluminum sacrificial anodes on steel structures for cathodic protection. The anode is the size of a large brick, cast around a U-shaped steel pipe that gets welded onto the structure. We bought most of our anodes from a local shop in Houston, but they bought scrap from various countries, including Russia. The (non-metallurgically inclined) representative for the operator buying the equipment wanted to reject a batch of anodes because he claimed that they were "made of Russian material", which was not allowed per their raw material spec. In fact, once that material is melted and re-cast in the USA (where the meltshop should be refining the chemistry and removing any deleterious impurities), it is born anew.

    Going back to your original question, I admit that I don't have first-hand aluminum melting/extraction experience so I'll be interested to see if anyone else weighs in but I don't think you could trace it back to ore deposits. Aluminum is a highly refined metal; the typical process is to dissolve it in molten salt and refine it electrolytically (it's called the Hall-Heroult process). This yields 99+% pure aluminum, and I believe the main impurity is iron. Unless your lab is set up to do something fancy like compare ratios of aluminum isotopes in your sample to known references from different mines around the world, I don't think this is going to yield any useful information.

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    Sean Piper
    Product / Process Metallurgist
    Ellwood Texas Forge Houston
    Houston TX
    773-524-8985
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  • 3.  RE: Metal country of origin

    E Virginia Chapter Adm
    Posted 03-05-2021 09:39

    Sean,

    I agree that if I were to melt it down it wouldn't matter.  I have some old parts of unknown origin that we are trying to trace.  I know it's a longshot for something like aluminum, I was just hoping for a metallurgical answer so we can have something a little more firm than guessing.



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    David Sapiro
    Engineer
    King George VA
    dosapiro@gmail.com
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  • 4.  RE: Metal country of origin

    Posted 03-05-2021 10:46
    Edited by Patricia Silvana Carrizo 03-05-2021 10:49
    Sorry David,

    In Aluminum and an old piece like you said here I never studied.

    Only one time a bodyguard shell from the Mendoza police, its a historical piece, was on something like the Alclad now, but without Aluminum.

    The chemical composition is mostly Ni : 31,2% and Cu: 2,98%, Cu is under and so you see it plated..from Napoleonic times, here came to the Mendoza police for to use in special celebrations, adquiried by second hand.

    Regards,

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    [Patricia Silvana] [Carrizo]
    [Ms.]
    [Chemical Engineer]
    [Archaeometallurgy Area - UTN FRM]
    [Mendoza] [Argentina]
    [+542615577229]
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  • 5.  RE: Metal country of origin

    Posted 03-06-2021 13:43
    Since aluminum has only one stable isotope (Al-27), I doubt that isotopic analysis will be much help.

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    John Grubb