How to eliminate borax flux on gold, silver and palladium ingots ?

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Uciocciu
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How to eliminate borax flux on gold, silver and palladium ingots ?

Post by Uciocciu » July 28th, 2020, 1:26 pm

Hi guys,

Here I am, it is my come-back, after confinement months due to covid19.

I hope everybody is fine.

I have got a simple question today: how to eliminate borax flux on gold, silver and palladium ingots ?

May be the process is different from a PM to another.

Could you give me your best tips ?
Thank you in advance,

Best,

Olivier from Corsica

( Welcome to Corsica ;))

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FrugalRefiner
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Re: How to eliminate borax flux on gold, silver and palladium ingots ?

Post by FrugalRefiner » July 28th, 2020, 3:27 pm

A soak in weak sulfuric acid (around 5% to 10%), heated gently should do the trick. Some people just boil in water, but depending on the amount of borax that can take a while.

Glad you're doing well. :)

Dave
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nickvc
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Re: How to eliminate borax flux on gold, silver and palladium ingots ?

Post by nickvc » July 28th, 2020, 3:54 pm

Borax dissolves readily in hcl, I don’t like sulphuric acid unless necessary for a recovery so try the Hcl.

Martijn
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Re: How to eliminate borax flux on gold, silver and palladium ingots ?

Post by Martijn » July 28th, 2020, 5:24 pm

I tried to clean borax from gold in warm diluted sulphuric acid and the borax turned milky but still was stuck to the gold.
I then put it in a test tube with 50% nitric and heated it with a hot air gun. It cleaned the button beautifully. No borax left and a nice shine to it.
That obviously would not work on silver or palladium.
For gold, i stick to nitric.
Martijn.

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Re: How to eliminate borax flux on gold, silver and palladium ingots ?

Post by Lino1406 » July 28th, 2020, 10:26 pm

I had good results with hot water and few drops of NaOH

Uciocciu
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Re: How to eliminate borax flux on gold, silver and palladium ingots ?

Post by Uciocciu » August 2nd, 2020, 11:37 am

Thank you so much for your tips , guys.

I will try all of your proposal: sulfuric, hcl and NaOH
Best

U ciocciu

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Re: How to eliminate borax flux on gold, silver and palladium ingots ?

Post by Geo » August 9th, 2020, 2:17 am

Borax is water soluble. It will dissolve in just water but like Dave said, it takes awhile. I'm afraid you will be disappointed by the length of time needed either way you go. Are you using the flux as a barrier to shield the metal from the atmosphere?
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