gold recovery

[KAREL Charvat]

I have recently tried to refine 18k gold to 24k with Aqua Regia process and I was not successful, reason being local 18k gold is green due to high content of silver, well over 10%. I then followed system of inquarting gold with copper (50% x50%) and then refining it with nitric and hydrochloric acid. When I started everything look OK, solution turn dark green and within 10 hrs. all gold and copper particles been dissolved. After acid reaction stop, I have added Bicarb Sodium and Urea, solution started releasing acid gasses, I have warm up the solution to speed it up. By adding precipitants color of solution turn dark blue, after while precipitation stopped I I was left with dark blue mud after researching it I have found few gold particles, I have started with 55g gold and I have recovered 14g of below 9 carat gold. I have saved all residues during refining and now I am trying to find solution to recover lost gold, with original calculation I should have been able to recover about 43g of 24 carats of gold. Question is, how do I doit?
Thanks.

 

[FrugalRefiner]

Have you tested your solution with stannous chloride to see if there is still gold in solution?

There are several things in your procedure that I would not agree with, like adding copper to inquart, and adding sodium bicarbonate and urea. But we can come back to that. Let's first determine if you have any gold in solution.

Dave

 

[Alondro]

Silver does not make gold turn green. It simply makes the gold more pale yellow until at higher percentages it will turn mostly silvery-colored.

COPPER makes gold turn green, and AR should dissolve that with ease.

 

[Yggdrasil]

Silver does not make gold turn green. It simply makes the gold more pale yellow until at higher percentages it will turn mostly silvery-colored.

COPPER makes gold turn green, and AR should dissolve that with ease.

I kind of disagree, Copper makes Gold red, Electrum are often considered green gold and that is a Gold-Silver alloy.
An alloy of 75% Gold 15% Silver 6% Cu and 4% Cd are dark green Gold.

 

[Martijn]

 

[Alondro]

I kind of disagree, Copper makes Gold red, Electrum are often considered green gold and that is a Gold-Silver alloy.
An alloy of 75% Gold 15% Silver 6% Cu and 4% Cd are dark green Gold.

I'm thinking of low Au content cheap jewelry (5K), where the copper is so high it starts to make the greenish corrosion.

 

[cejohnsonsr1]

The first step after inquartation should have been removal of everything that isn’t gold with distilled water and Nitric. Not AR. You can’t refine until you recover. All you did was dissolve everything into a mixed up solution of all the metals without removing any of them from the equation. Cement it all out, melt into shot or flake and start over using distilled water and Nitric. Sreetips has several videos showing how and explaining why.

 

[sketcho]

The first step after inquartation should have been removal of everything that isn’t gold with distilled water and Nitric. Not AR. You can’t refine until you recover. All you did was dissolve everything into a mixed up solution of all the metals without removing any of them from the equation. Cement it all out, melt into shot or flake and start over using distilled water and Nitric. Sreetips has several videos showing how and explaining why.

Exactly my thoughts! Remove all base metals before refinning ! Sreetips videos is just the best! He has made scrap gold refinning simple and straightforward

 

[Martijn]

I would skip the 'melt into shot' step and go straight for dissolving in diluted nitric.
Carefull with nitric additions on metal powder. Slow and small amounts on low heat to avoid boil over and BFRC.

 

[Martijn]

Exactly my thoughts! Remove all base metals before refinning ! Sreetips videos is just the best! He has made scrap gold refinning simple and straightforward

Sreetips is one of the best out there. He does however make small mistakes every now and then, but he shows them and lets us learn from it.

One thing I keep noticing in his videos is that he cools with ice and then adds SMB without filtering any AgCl out first.
Isn't it supposed to be: cool and dilute to push out AgCl and then filter?

Martijn.

 

[cejohnsonsr1]

Sreetips is one of the best out there. He does however make small mistakes every now and then, but he shows them and lets us learn from it.

One thing I keep noticing in his videos is that he cools with ice and then adds SMB without filtering any AgCl out first.
Isn't it supposed to be: cool and dilute to push out AgCl and then filter?

Martijn.

He usually uses ice either to cool the solution prior to precipitation or to keep the solution cool if there’s more than about 3 oz. Precipitation with SMB is an exothermic reaction and produces quite a bit of heat. The silver that precipitates from cooling should all be removed by filtration, which always precedes precipitation.

 

[Martijn]

makes sense, large quantities of gold.. I don't have that 'problem'

 

[Yggdrasil]

makes sense, large quantities of gold.. I don't have that 'problem'

I have the same challenge, the yellow stuff simply do not float in my direction

 

[Junior2021]

makes sense, large quantities of gold.. I don't have that 'problem'

I have the same challenge, the yellow stuff simply do not float in my direction

Meu amigo bom dia, agradeço por todo conhecimento adquirido neste fórum. Me ajude por favor não sei se postei no lugar certo desculpe se errei, mas estou um pouco desesperado.

Me surgiu um problema
Peço que me ajudem por favor.
Estou trabalhando em uma solução com cerca de 6 onças, sei que deveria ter dividido em 3 lotes porém não o fiz. O material é dedos de ouro foram bem limpos eliminei o máximo de cobre e estanho com lavagens a nítrico, água quente, e clorídrico separadamente.

Solução 500ml de ácido clorídrico 37% e fui adicionando nítrico de 20ml +20ml +10ml e no final 5ml
Até as folhas de au limpas dissolver.

Quando adicionei MBS ouve uma enfervecencia e o MBS, disolvia e não trocava ions com a solução liberando ouro. Acredito que a solução esteja extremamente ácida.

Tentei erradamente adicionar um pouco de soda cáustica para elevar o ph e derrubar o ouro com um pouco de zinco a reação continua enfervecendo sem resultado de precipitação indicando ácidos Hno3 livre na solução.
Eu sempre precipito as minhas águas regias AR a quente muito quente. Será que isso pode gerar problema? Tenho uma solução de cerca de 2litros era 500ml no começo Acredito que a adição de água em excesso me prejudicou também.

A solução de AR continua com positivo forte no teste de stanho 2
A evaporação, redução da solução e eliminação do hno3 pode me ajudar?

OBS: Deste mesmo material tirei 4 onças de au e não tive problemas, agora estou tendo me ajudem por favor.

 

[Martijn]

I can only understand part of your problem but not all of it. Try to write it in English or use a translator.
But it sounds like you still have all or part of your gold in solution and some free nitric.

We really need to understand the details to help you.

 

[Junior2021]

I can only understand part of your problem but not all of it. Try to write it in English or use a translator.
But it sounds like you still have all or part of your gold in solution and some free nitric.

We really need to understand the details to help you.

 

[Junior2021]

My friend good morning, for all the knowledge acquired in this forum. Please help me, I don't know if I posted in the right place, sorry if I'm wrong, but I'm a little desperate.

I had a problem
I ask you to help me please.
I'm working on a solution about 6oz, I know it should have been completely different in 3 batches but I did. The material and gold fingers were well cleaned and as much copper and tin as possible with nitric, hot water and hydrochloric washes.

500ml solution of 37% hydrochloric acid and I was adding 20ml +20ml +10ml nitric and at the end 5ml
Until the clean au leaves dissolve.

When the MBS heard an effervescence and the MBS, it dissolved and did not exchange ions with the solution releasing gold. I believe the solution is extremely acidic.

I tried wrongly to add a little caustic soda to raise the and the gold with a little zinc in the reaction keeps boiling giving up the solution of free Hno3 direct solution.
I always rush my AR regal waters to hot very hot. Could this cause a problem? I have a solution of about 2 liters it was 500ml at the beginning I believe the addition of excess water harmed me too.

The reduction in AR continues with a strong positive in the stan 2 test
Can evaporation, solution solution and hno3 elimination help me?

OBS: This same material I took 4 ounces of au and it has no problems, now I'm having help me in favor.
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[Junior2021]

My friend Martin you always help me with your posts on the forum, I do a lot of research on the forum

The precipitate is part of the au that I managed to recover. only precipitated a part, the solution was putting the gold back into the solution. Could this be the excess of free nitric acid in RA?

The precipitation was not completed because the precipitate is returning to the AR solution.

I started an evaporation of free nitric because I believe that's it. I cleaned the gold leaves very well with nitric oxide. Before dissolving in solution, I need to know if I'm on the right track.

help me please my friend i need to recover this gold to help my family.

 

[Junior2021]

I can only understand part of your problem but not all of it. Try to write it in English or use a translator.
But it sounds like you still have all or part of your gold in solution and some free nitric.

We really need to understand the details to help you.

I'm writing in English but it comes out in Brazilian Portuguese

 

[Yggdrasil]

My friend Martin you always help me with your posts on the forum, I do a lot of research on the forum

The precipitate is part of the au that I managed to recover. only precipitated a part, the solution was putting the gold back into the solution. Could this be the excess of free nitric acid in RA?

The precipitation was not completed because the precipitate is returning to the AR solution.

I started an evaporation of free nitric because I believe that's it. I cleaned the gold leaves very well with nitric oxide. Before dissolving in solution, I need to know if I'm on the right track.

help me please my friend i need to recover this gold to help my family.

You need somehow to denox your solution.
The fact that the precipitate dissolves again indicate too much Nitric.
Do you have access to Sulfamic acid?
If not, do you have a button of Gold you can dissolve from?
If so, weigh the button and put it into the solution while hot. Let it be there til nothing more happens, add some more HCl. If there is no reaction, take the button out and weigh it so you know how much Gold the solution has “borrowed”.
Now precipitate your Gold and weigh what was borrowed and put it back to the button.
The rest is your Gold from this batch.