Aqua regia a lot of SMB...

[Alexander_Hun]

Hello!

Thank you for being here, I refine gold-plated contacts, of course based on videos.
In the first step, I etch away the excess with nitric acid, dissolve the gilding in aqua regia, and reduce it with SMB.
However, unlike the videos, I have to use SMB to start the reaction, I don't understand what the problem is?
I put it in with a spoon and it disappears with a big hiss, is the acid too much compared to the gold?
This is my first question
The second:
I could only buy 54% nitric acid, it dissolves the gold, so in principle everything should work the same but slower? I accept all advice,

(I use exhaust, gas mask, rubber gloves, I pay attention to everything)

Thank you for the answers, I am attaching some pictures, I used a translation program, sorry for the mistakes.

 

[Yggdrasil]

Hello!

Thank you for being here, I refine gold-plated contacts, of course based on videos.
In the first step, I etch away the excess with nitric acid, dissolve the gilding in aqua regia, and reduce it with SMB.
However, unlike the videos, I have to use SMB to start the reaction, I don't understand what the problem is?
I put it in with a spoon and it disappears with a big hiss, is the acid too much compared to the gold?
This is my first question
The second:
I could only buy 54% nitric acid, it dissolves the gold, so in principle everything should work the same but slower? I accept all advice,

(I use exhaust, gas mask, rubber gloves, I pay attention to everything)

Thank you for the answers, I am attaching some pictures, I used a translation program, sorry for the mistakes.

You use way too much Nitric.
Cover the foils with HCl and add Nitric drop by drop. I can’t remember by one ml of Nitric in HCl will dissolve a significant amount of Gold.

Read CM Hokes book it is in the Libraryvand the signature of some of the moderators search this forum. Here is a link:
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798

 

[Alexander_Hun]

You use way too much Nitric.
Cover the foils with HCl and add Nitric drop by drop. I can’t remember by one ml of Nitric in HCl will dissolve a significant amount of Gold.

Read CM Hokes book it is in the Libraryvand the signature of some of the moderators search this forum. Here is a link:
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798

Hi!
Thanks for the reply!!!
So when making aqua regia, isn't the 3:1 ratio important?
Hydrochloric acid and add the nitric acid until it starts to dissolve the gold?

 

[Yggdrasil]

The original recipe is that yes. But for our use that is not necessary. Actually it will usually create trouble. There is one thing we do not want and that is excess Nitric.

For foils like you have the best is HCl/Peroxide or HCl/Bleach.
One thing important with bleach is to add just small amounts at a time, since it will neutralize the solution if you overdo the bleach.
But it will be destroyed by a quick simmer after dissolving.

There are much more to say about this, but it is already here on the forum.
Read Hokes book and search the forum.

 

[Alexander_Hun]

The original recipe is that yes. But for our use that is not necessary. Actually it will usually create trouble. There is one thing we do not want and that is excess Nitric.

For foils like you have the best is HCl/Peroxide or HCl/Bleach.
One thing important with bleach is to add just small amounts at a time, since it will neutralize the solution if you overdo the bleach.
But it will be destroyed by a quick simmer after dissolving.

There are much more to say about this, but it is already here on the forum.
Read Hokes book and search the forum.

Hi!

I tried what you wrote, aqua regia also works in a ratio of 10:1, although it works slowly.
This is another question, I dissolved a lot of gold-plated contacts in nitric acid, fine white sand constantly settled on the bottom of the glass, quite a lot, what could this be?

Thanks!

 

[Yggdrasil]

Hi!

I tried what you wrote, aqua regia also works in a ratio of 10:1, although it works slowly.
This is another question, I dissolved a lot of gold-plated contacts in nitric acid, fine white sand constantly settled on the bottom of the glass, quite a lot, what could this be?

Thanks!

The gold was left I guess, since Nitric don’t dissolve gold.
But depending on the other elements of the alloy it can be any non soluble salt of nitric of what ever metal is in the alloy.

 

[Biom]

Aqua regia can be 4 to 1 .or. 3 to 1 or just drop by drop nitric . You need heat .stannous chloride .very important and urea to make sure you don't have access nitric .and then precipitation . You have to do it step by step .and test with stanouss as you go .and it's deferent factor if you have other metal with gold

 

[Alexander_Hun]

Aqua regia can be 4 to 1 .or. 3 to 1 or just drop by drop nitric . You need heat .stannous chloride .very important and urea to make sure you don't have access nitric .and then precipitation . You have to do it step by step .and test with stanouss as you go .and it's deferent factor if you have other metal with gold

Hi, do you need urea before reduction? There are those who recommend it, and those who say that we should not use urea

 

[Biom]

If you have any axes nitric yes because once you start precipating gold .it will drop and redesolve in same time more you add smb more drop and redesolve because you still have aqua regia working .and in the end you have problems either to much salt your value is not going no where it can be recovered.urea will kill nitric or most part of it .there is some vedios you can watch in YouTube to give you an aidea

 

[Biom]

Urea before preciptation of caurs need to take exes nitric that the easy way

 

[Biom]

That's why you need heat in aqua regia so you don't add to much nitric because if not keept hot it will stop or you think it stoped and you add more nitric but if it keept hot you will know whene it's done .that way you not have any problems precipating and test as you go

 

[Jimbriese]

No do not use urea it’s for the garden. Use sulfamic acid to denox then filter. Or evaporate like hokes explains very well in her book. Urea can have unwanted results and may create an explosive

 

[Shark]

If you use urea, it does not kill the nitric acid, it temporarily removes the NOx gas from the AR, any remaining nitric acid will eventually regenrate the NOx and redisolve the gold if not processed fairly quickly. If you use urea then need to remove any potential lead from the AR, you have to use another chemical. Sulfuric acid or sulfamic acid will drop any lead as a filterable sulfate. You will then have used two chemicals for two separate reactions. If you use sulfamic first, you actually remove any excess nitric acid as well as the NOx it generates, AND drops the lead as a filterable sulfate. If you use sulfamic, you accomplish both needed reactions with one chemical. In this case sulfamic is an example of "less is more".

 

[Alexander_Hun]

Thanks for the advice, today's test with urea.

 

[Shark]

That is some good materials. Are you running them in AR only?

Nice little button of gold as well.

 

[Alexander_Hun]

That is some good materials. Are you running them in AR only?

Nice little button of gold as well.

Hi, military grade, lots of gold on it. What does AR mean? Sorry, I don't understand the abbreviations, I'm using a translator

 

[Shark]

AR = Aqua Regia

Thanks for reminding me of the language and abbreviations.

 

[Alexander_Hun]

AR = Aqua Regia

Thanks for reminding me of the language and abbreviations.

Yes, it's only AR that I've used so far, but now I pay attention to making it with as little nitric acid as possible.

 

[FrugalRefiner]

Hi, military grade, lots of gold on it. What does AR mean? Sorry, I don't understand the abbreviations, I'm using a translator

For terms you don't understand, see A Glossary of Common Terms.

Dave

 

[Biom]

Thanks for the advice, today's test with urea.

Looks great use stanous chloride make sure there is no gold left in AR