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

[Uciocciu]

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 )

 

[FrugalRefiner]

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

 

[nickvc]

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

 

[Martijn]

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.

 

[Lino1406]

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

 

[Uciocciu]

Thank you so much for your tips , guys.

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

U ciocciu

 

[Geo]

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?