# Oxalic Acid Makes Fine Gold 99.93% XRF



## kadriver (Oct 23, 2012)

I make this bar from some gold filled scrap and some karat scrap. I think it is the purest bar I have ever made.

After inquartation, I double refined it using aqua regia to dissolve and sodium metabisulfite to precipitate first, then hydrochloric acid and clorox to dissolve and Oxalic acid for the second precipitation.

To see how I did it click on this link.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=15603

kadriver


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## g_axelsson (Oct 23, 2012)

That is just beautiful! Good work and thanks for showing it.

I have 18 g of gold powder that I got from e-waste, collecting more to re-refine later on. Seeing pictures like this I start to feel that it's soon time to do that second refining.

/Göran


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## tenten (Oct 23, 2012)

Beautiful Gold 8)


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## Anonymous (Oct 23, 2012)

How much does it weigh, and how much material did it take to get that?

Very clean looking gold. It looks pure to me.


Kevin


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## RoboSteveo (Oct 23, 2012)

That's beautiful!!
Great Job


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## samuel-a (Oct 23, 2012)

Nice kadriver

Now you know that the XRF machine used is not calibrated for bullion :mrgreen:


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## glondor (Oct 23, 2012)

Very nice bar!


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## Lou (Oct 23, 2012)

So let me get this straight...

You inquart and part to get 98-99.5% Au. You redissolve it and filter then reduced with a sulfite and you get 99+ and then you redissolve and use oxalic and only get 99.93?

You should be at 3N5 just by inquart and SO2 coupled with careful washing/ammonia.

With oxalic, you should be in excess of 5N after those steps.

The only way to measure that is by a difference measurement.


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## kadriver (Oct 24, 2012)

Lou, do you think that the bar is actually closer to 4N?

The refiner's assay is all I have to go by.

kadriver


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## qst42know (Oct 25, 2012)

I have a question.

If a button was not commercially pure by XRF and the button was remelted wouldn't the second XRF number be lower as more base metal oxides are pulled to the surface?


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## Lou (Oct 25, 2012)

Yes, but how much that impacts this reading is contingent on how powerful the XRF is. Given that NTR is ubiquitous, they cannot afford a very expensive instrument at every location.


Oxalic acid reliable produces 5N gold after sulfite.

Personally, I think the XRF is meaningless on purities above 3N.
Corrected FA, GDMS and other subtraction methods are to be trusted.


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## HAuCl4 (Oct 26, 2012)

KA: I'm almost sure you can convince them to pay you 98.5% or even 99% of spot for your bars. No harm in asking. :idea:


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## kadriver (Oct 26, 2012)

I'll ask them.


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