Gold recovery from smelter slags

[user 72133]

¿La escoria la produce usted?
¿O es escoria vieja lo que está tratando?

i produce it each time i melt gold...

in each smelting I use borax and sometimes sodium carbonate

gold comes from melting pieces of jewelry, rings, bracelets, watches... to make an ingot, not from cyanide leaching.

there isn't carbon, i think i have that products:



2 tons in AR is not a good idea... i know..
Maybe calcining, the slag melt at lower temperatures than gold... but gold so small would be trapped in them...
What means panning? is like calcining or i didn't undertand well?
i refer to use a phisical method, increasing the temperature gradually to obtain liquid slag and solid gold... but gold is crushed too so it could be trapped...

 

[Yggdrasil]

i produce it each time i melt gold...

in each smelting I use borax and sometimes sodium carbonate

gold comes from melting pieces of jewelry, rings, bracelets, watches... to make an ingot, not from cyanide leaching.

there isn't carbon, i think i have that products:

View attachment 58189

2 tons in AR is not a good idea... i know..
Maybe calcining, the slag melt at lower temperatures than gold... but gold so small would be trapped in them...
What means panning? is like calcining or i didn't undertand well?
i refer to use a phisical method, increasing the temperature gradually to obtain liquid slag and solid gold... but gold is crushed too so it could be trapped...

What do you do to the Gold before smelting/melting?
Do you refine it?
Do you use flux to clean it up?
What karat is it?

 

[user 72133]

What do you do to the Gold before smelting/melting?
Do you refine it?
Do you use flux to clean it up?
What karat is it?

No no, i introduce the pieces of jewelry directly in the crucible, and i do an ingot with 18K normally, sometime 9K sometime 14K... . I refine it after, when i have 1kg more less and after analyse each of them, i make them shot together and i refine it.
i use flux to smelt the pieces and to clean the crucible after. and the slag is what i save. this slag cotains a little bit of gold, gold that i want to recover, becouse i save lots of slag...

 

[Yggdrasil]

No no, i introduce the pieces of jewelry directly in the crucible, and i do an ingot with 18K normally, sometime 9K sometime 14K... . I refine it after, when i have 1kg more less and after analyse each of them, i make them shot together and i refine it.
i use flux to smelt the pieces and to clean the crucible after. and the slag is what i save. this slag cotains a little bit of gold, gold that i want to recover, becouse i save lots of slag...

The lower karat may need flux, but 14 and up should need no flux.
Which also remove the needs of cleaning up the slag.
The lower karats may or may not need flux, in this case a bit of Borax.
But that should be sufficient.

Any way if you just melts Gold together without refining it pyrometallurgically it is called melting not smelting.

 

[Martijn]

No no, i introduce the pieces of jewelry directly in the crucible, and i do an ingot with 18K normally, sometime 9K sometime 14K... . I refine it after, when i have 1kg more less and after analyse each of them, i make them shot together and i refine it.
i use flux to smelt the pieces and to clean the crucible after. and the slag is what i save. this slag cotains a little bit of gold, gold that i want to recover, becouse i save lots of slag...

For melting metals together you don't need flux. So you can eliminate slag with pm's in it.
I'm curious, do you refine gold above 6K without inquarting?

 

[user 72133]

4 metals gave you good advice.
Are you smelting Gold?
If so what is your flux recipe?

Or are you melting Gold into a new form?
If so, no Borax/flux is needed.

Urea is a fertiliser and best used in the garden.
To remove Nitric from solutions use less Nitric (best) or Sulfamic acid (next best)

By the way... about urea, let me say you that it works.
and i can explain to you with reactions.
Urea reacts with nitric acid to produce nitrogen , carbon dioxide and water, removing the excess of nitric of your AR. As you can see in the first reaction in this pic.

I know urea is a fertiliser, as sugar for example is a sweetener, but you can use it to reduce the silver oxide taking advantage of their reducing aldehydes.

the same reagent can have different uses, do not close doors

 

[user 72133]

For melting metals together you don't need flux. So you can eliminate slag with pm's in it.
I'm curious, do you refine gold above 6K without inquarting?

no, i do a pretreatment with diluted nitric acid to remove a big quantity of the base metals and silver. next i filter and refine it as normal with AR.

 

[Yggdrasil]

By the way... about urea, let me say you that it works.
and i can explain to you with reactions.
Urea reacts with nitric acid to produce nitrogen , carbon dioxide and water, removing the excess of nitric of your AR. As you can see in the first reaction in this pic.

I know urea is a fertiliser, as sugar for example is a sweetener, but you can use it to reduce the silver oxide taking advantage of their reducing aldehydes.

the same reagent can have different uses, do not close doors

We have been through this many times in this forum.
Yes, it works to a certain degree.
But it has also some shortcomings that the use of less Nitric or the use of Sulfamic acid don’t.
It can in certain settings create explosive compounds, this is something we don’t want inside our Gold. It will not decompose the surplus nitrates either.
Which Sulfamic acid does by transforming them and the Nitric to Sulfuric acid which removes the need to add Sulfuric to remove the Lead.

 

[user 72133]

For melting metals together you don't need flux. So you can eliminate slag with pm's in it.
I'm curious, do you refine gold above 6K without inquarting?

flux have two advantages, first reduce the temperature of smelting, and second recover the shit that the pieces could have, like grease, stons, some lead...
i only dont use flux when i smelt fine gold.

 

[user 72133]

The lower karat may need flux, but 14 and up should need no flux.
Which also remove the needs of cleaning up the slag.
The lower karats may or may not need flux, in this case a bit of Borax.
But that should be sufficient.

Any way if you just melts Gold together without refining it pyrometallurgically it is called melting not smelting.

Oh thanks! i really needed that information!! "Any way if you just melts Gold together without refining it pyrometallurgicallyit is called melting not smelting."
I'm Spanish and i dont controle really well this terms. Thanks ^^

 

[Yggdrasil]

no, i do a pretreatment with diluted nitric acid to remove a big quantity of the base metals and silver. next i filter and refine it as normal with AR.

As Martijn indicated, inquarting is the standard procedure for all Gold alloys over 6 karat. Preferably with Silver.
Then parting it in Nitric and if done properly you will already be at more than 99 Gold.

 

[Yggdrasil]

Oh thanks! i really needed that information!! "Any way if you just melts Gold together without refining it pyrometallurgicallyit is called melting not smelting."
I'm Spanish and i dont controle really well this terms. Thanks ^^

This is an international forum which deals with different chemistry related topics and as such proper nomenclature is essential both for precision and understanding.

Try to adhere to that please.

 

[Yggdrasil]

flux have two advantages, first reduce the temperature of smelting, and second recover the shit that the pieces could have, like grease, stons, some lead...
i only dont use flux when i smelt fine gold.

I see now Spanish is like my language, it do not distinguish between smelting and melting.

 

[Martijn]

By the way... about urea, let me say you that it works.
and i can explain to you with reactions.
Urea reacts with nitric acid to produce nitrogen , carbon dioxide and water, removing the excess of nitric of your AR. As you can see in the first reaction in this pic.

I know urea is a fertiliser, as sugar for example is a sweetener, but you can use it to reduce the silver oxide taking advantage of their reducing aldehydes.

the same reagent can have different uses, do not close doors

This is an old discussion. opinions differ. This thread is interesting one to read. Consensus on GRF is: do not use it in refining.

I won't, because the experienced members say so. I also don't use it because the little HNO3 that might be left, will get consumed by precipitating the gold anyway. NO will gas off.

I tried some liquid descaler sulfamic acid a couple of weeks ago for the first time, right after digesting the last bit of gold at 80 degr. C, and it worked great, for that 1ml that was in there.
https://goldrefiningforum.com/threads/urea-its-use-in-refining.22734/

 

[user 72133]

The lower karat may need flux, but 14 and up should need no flux.
Which also remove the needs of cleaning up the slag.
The lower karats may or may not need flux, in this case a bit of Borax.
But that should be sufficient.

Any way if you just melts Gold together without refining it pyrometallurgically it is called melting not smelting.

some of my slag comes to smelt jelwelry wastes too, trash , polished, that jewelers accumulate and i smelt with fluxs and i recover in the cone mold...
Also i have slags from smelt silver clorures... and all kinds of recovering procedures.

 

[user 72133]

This is an international forum which deals with different chemistry related topics and as such proper nomenclature is essential both for precision and understanding.

Try to adhere to that please.

Of course, really thanks for your corrections, dont dude to continue telling me if i am wrong

 

[user 72133]

This is an old discussion. opinions differ. This thread is interesting one to read. Consensus on GRF is: do not use it in refining.

I won't, because the experienced members say so. I also don't use it because the little HNO3 that might be left, will get consumed by precipitating the gold anyway. NO will gas off.

I tried some liquid descaler sulfamic acid a couple of weeks ago for the first time, right after digesting the last bit of gold at 80 degr. C, and it worked great, for that 1ml that was in there.
https://goldrefiningforum.com/threads/urea-its-use-in-refining.22734/

I have never tried sulfamic acid. Thanks for the info, I'll keep it in mind.


I had already read about this in the forum but I had always thought that urea was the best for having the reactions in sight. But I'll find out about the chemistry of sulfamic acid.
thanks.

 

[Yggdrasil]

Of course, really thanks for your corrections, dont dude to continue telling me if i am wrong

We will always correct what is wrong.
No matter who it is.
I have done and said wrong things too.
And if no one corrected me I would continue to be wrong, so I’m grateful for any correction.
We do not do this to be bad, but for the best of the forum and the users.

 

[HarryLee1506]

In my country, metallurgical slag will be mixed with flux and lead to remelt 2-3 times to recover gold and silver. That treated slag still contains an amount of gold and silver which I have millions of tons... I am trying to find a solution to recover this.

 

[Martijn]

In my country, metallurgical slag will be mixed with flux and lead to remelt 2-3 times to recover gold and silver. That treated slag still contains an amount of gold and silver which I have millions of tons... I am trying to find a solution to recover this.

At some point it is no longer worth the time to chase traces.

My definition of "ore":
Any substance containing valuable elements or compounds that are economically retractable. The key word here is economically, so "worth your time".

If there are still values worth your time after smelting slags for the second time, look for a different flux, and collector metal, amount or form, for the first and second smelt. How much time, effort and energy does resmelting 2-3 times cost?