# Aqua regia a lot of SMB...



## Alexander_Hun (Jul 9, 2022)

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.


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## Yggdrasil (Jul 9, 2022)

Alexander_Hun said:


> 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.
> ...


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:








Screen Readable Copy of Hoke's Book


About 9 months ago I posted my printer friendly version of Hoke's book. In the process of creating that version I corrected many errors that had been generated by the OCR software when the book was originally digitized. I also rescanned all of the photos and drawings and included some text...




goldrefiningforum.com


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## Alexander_Hun (Jul 9, 2022)

Yggdrasil said:


> 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:
> ...


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?


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## Yggdrasil (Jul 9, 2022)

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.


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## Alexander_Hun (Jul 11, 2022)

Yggdrasil said:


> 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.
> ...


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!


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## Yggdrasil (Jul 11, 2022)

Alexander_Hun said:


> 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?
> ...


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.


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## Biom (Jul 11, 2022)

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


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## Alexander_Hun (Jul 11, 2022)

Biom said:


> 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


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## Biom (Jul 11, 2022)

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


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## Biom (Jul 11, 2022)

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


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## Biom (Jul 11, 2022)

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


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## Jimbriese (Jul 11, 2022)

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


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## Shark (Jul 11, 2022)

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".


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## Alexander_Hun (Jul 12, 2022)

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


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## Shark (Jul 12, 2022)

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

Nice little button of gold as well.


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## Alexander_Hun (Jul 12, 2022)

Shark said:


> 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


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## Shark (Jul 12, 2022)

AR = Aqua Regia

Thanks for reminding me of the language and abbreviations.


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## Alexander_Hun (Jul 12, 2022)

Shark said:


> 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.


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## FrugalRefiner (Jul 12, 2022)

Alexander_Hun said:


> 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


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## Biom (Jul 12, 2022)

Alexander_Hun said:


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


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


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## Yggdrasil (Jul 12, 2022)

Biom said:


> 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


Urea is the wrong chemical for this.
It only temporarily remove parts of the problem and under certain conditions may create explosive compounds.
The best to use is Sulfamic acid in a hot solution, it converts any Nitric and NOx to Sulfuric acid.


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## goldshark (Jul 12, 2022)

Maybe a quick description of what using SMB in a high Nitric environment does, by a chemist. Such as ,if you don't use Sulfamic to neutralize excess nitric, but keep adding SMB till it starts piling in heaps at the bottom of the beaker, but no Gold powder, or gold powder appears , then disappears time and again,despite adding even more SMB till it overflows the beaker. I did this once, laugh about my stupidity now. This is what I like about this forum, people are patient. They answer questions that could be obtained by a comprehensive reading of Hoke's. Thanks all for our patience.


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## Yggdrasil (Jul 12, 2022)

One can always bubble SO2 through the solution.
It will sooner or later deplete the Nitric without adding much to the solution.
It may however require a boatload of SMB to generate the SO2


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## Alexander_Hun (Jul 13, 2022)

Biom said:


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


I made stannous chloride, it works very well


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## Biom (Jul 13, 2022)

Alexander_Hun said:


> I made stannous chloride, it works very well


Good luck great .stanous chloride it's your eyes in refining .you can progress better without loosing any gold


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## Alexander_Hun (Jul 13, 2022)

Hello, when melting gold, what causes the gold to change color as it cools down? At the bottom, where the jar was, it is a beautiful yellow, at the top it looks like copper. But this is only on the surface, it disappears with more melting.


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## Martijn (Jul 13, 2022)

Impurities like copper oxide. Sprinkle a little borax at the end and see if disappears.
Are you using a clean crucible?


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## Alexander_Hun (Jul 13, 2022)

Martijn said:


> Impurities like copper oxide. Sprinkle a little borax at the end and see if disappears.
> Are you using a clean crucible?


Hi, unfortunately I melt it together with filter paper, it's not completely clean, but I didn't melt any other material in it, only gold. I use borax, if I throw it in acid afterwards, it will become lighter after a while


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## Shark (Jul 13, 2022)

Alexander_Hun said:


> if I throw it in acid afterwards, it will become lighter after a while


Only on the outside. The inside of the gold will still contain some copper. Sometimes one or two grains of sodium nitrate or potassium nitrate added to the melt will remove small amounts of impurities. It is best to remove them in the refining. Better filtering along with better washing of the gold powders will make large increases in gold quality. 

It is possible that these impurities added to your gold floating in your original post.


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## Alexander_Hun (Jul 13, 2022)

Shark said:


> Only on the outside. The inside of the gold will still contain some copper. Sometimes one or two grains of sodium nitrate or potassium nitrate added to the melt will remove small amounts of impurities. It is best to remove them in the refining. Better filtering along with better washing of the gold powders will make large increases in gold quality.
> 
> It is possible that these impurities added to your gold floating in your original post.


If copper also dissolves with gold in the AR, will only the precious metals separate out during the reduction? Does it affect the final quality?


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## Shark (Jul 13, 2022)

When the gold drops some amount of copper will drop with it. An excess of SMB will cause more copper to drop with the gold. One way to stop this is to remove most of the copper before using AR. A bath in hydrochloric acid for a few days will remove copper. Also a bath in nitric acid alone will work. Just use one for the first time allowing it time to work. Remove the acid of choice, then proceed to AR.

My preferred method is to drop the gold and wash the powders well. I use three boiling water washes, then a boiling hydrochloric acid wash, then again with three boiling water washes. Repeat until the acid wash shows no signs of discoloration. Then I go back to AR and repeat it all over again.

All of this can change depending on the material I am running, and what the expected contaminates may be. Good filtering is important also to the removal of many contaminants in the refining.

Very careful with boiling acid, it very unforgiving.


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## Biom (Jul 13, 2022)

Smb very selective for gold .you may have some drag down .it's very important to clean the powder to high purity before melting .you may use some sodium bicarbonate see if


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## Biom (Jul 13, 2022)

Any gold powder after precipate should be cleaned and washed very truly.you may have drag down if you use extra precipetan but it's not a problem as long as you clean it and some pinch sodium nitrate some sodium bicarbonate as a flux .so many refiners redesolve again in A R second time and use defrent precipetan .like if start with smb . Second time use ferouss solfate.because each one of them have deferent drag down .that if you talking about a lot of gold .


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## Biom (Jul 13, 2022)

Use shark advice


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## Biom (Jul 13, 2022)

Shark explained best way


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## Biom (Jul 14, 2022)

Biom said:


> Shark explained best way


Shark explained better .iam from Morocco .it's hard for me to explain cause of the language .


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## Alexander_Hun (Jul 14, 2022)

Thanks for all the advice! The Hungarian language is also quite difficult, but I am glad to have found such a good forum where everyone is helped patiently!!
I have a question, I process the gold-plated connectors shown in the pictures above, cut them into small pieces, the nitric acid works well for a while on the copper inside... However, after a while it cannot get inside, it cannot finish the job. I tried to heat it, it gets better for a while, but there is always copper in it.... How would you do it?


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## Biom (Jul 14, 2022)

What other matels you have for sure and how much in the alloy


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## Jimbriese (Jul 14, 2022)

Decant off the spent acids and add fresh water and nitric until no more reaction. Then rinse well. Dissolve clean gold in Aqua Regia. Drop with your choice of precipitate.


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## Alexander_Hun (Jul 14, 2022)

Jimbriese said:


> Decant off the spent acids and add fresh water and nitric until no more reaction. Then rinse well. Dissolve clean gold in Aqua Regia. Drop with your choice of precipitate.


Hi!

That's how I do it, but the connectors are so thin that the acid can't penetrate after a while, the gilding stays there like a frame and the acid doesn't go in, maybe because of the bubbles..


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## Shark (Jul 14, 2022)

If the gold is thick enough it can stop the nitric acid process. Gold filled will do the same thing. It leaves a shell of the outside gold and some of the copper or other base metals inside. This is why a good washing process is needed for the gold powders. Also, it is why we often process the powders a second time.

Often it is suggested to post the complete process one intends to use step by step. This helps us to find the area that may cause problems. I have looked but cannot find the post about “ “getting gold bright and shiny”. Maybe someone can post that here for us.


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## Biom (Jul 14, 2022)

If not much you have to refine .after some nitric .just go to A R desolve every thing .and second time AR with defrent precipitant .that's why need to know what exactly metals you have in alloy .if you dealing with just gold and copper is defrent story if you dealing with gold .tin .silver .you need to know what metals beside gold .you dealing with


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## Biom (Jul 14, 2022)

Shark said:


> If the gold is thick enough it can stop the nitric acid process. Gold filled will do the same thing. It leaves a shell of the outside gold and some of the copper or other base metals inside. This is why a good washing process is needed for the gold powders. Also, it is why we often process the powders a second time.
> 
> Often it is suggested to post the complete process one intends to use step by step. This helps us to find the area that may cause problems. I have looked but cannot find the post about “ “getting gold bright and shiny”. Maybe someone can post that here for


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## Biom (Jul 14, 2022)

Need to know exactly what metal he's dealing with .in melt need to add sodium bicarbonate if it only the gold in melt if there is other metal can cause tarnsh


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## Martijn (Jul 14, 2022)

Shark said:


> I have looked but cannot find the post about “ “getting gold bright and shiny”. Maybe someone can post that here for us.


Sure we can: 








Getting pure gold (shining)


Hello, I would like to know what I must add/change to a standard AR process to get pure gold after melting it. Most of the gold buttons I get are not completly shining and seem to have a very thin layer of impurties. How can I correct that ? Thanks




goldrefiningforum.com


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## Biom (Jul 14, 2022)

Sodium bicarbonate in melt.


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## Martijn (Jul 14, 2022)

Biom said:


> Need to know exactly what metal he's dealing with .in melt need to add sodium bicarbonate if it only the gold in melt if there is other metal can cause tarnsh


Gold. If anything else is in there, he did not refine it good enough and should not be melting yet and refine again.


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## Alexander_Hun (Jul 14, 2022)

Thanks!

Maybe I will refine the gold again, what I usually do is put nitric acid on the reduced gold powder so that if it contains other metals besides the gold, do you think it's a good idea?


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## Biom (Jul 14, 2022)

Ok need to know how much gold you dealing with if you know what other metal .if cant find out what you have .then use nitric 50 water and then AR with what left precipitate .and .AR second time with deferent precipitant . Use shark advice on waching that's one option .but try to find out what you have .if you making this to sale .sale it the way it is don't worry about shiny .an refiner will finish it .need to know what you have how much .


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## Biom (Jul 14, 2022)

Martijn said:


> Gold. If anything else is in there, he did not refine it good enough and should not be melting yet and refine again.


Yes shiny gold is from the start


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## Martijn (Jul 14, 2022)

Alexander_Hun said:


> Thanks!
> 
> Maybe I will refine the gold again, what I usually do is put nitric acid on the reduced gold powder so that if it contains other metals besides the gold, do you think it's a good idea?


If you got rid of all traces of HCl or if you accept a part of the gold redissolving from weak AR, yes. 

And you should/could save that spent nitric for a future dirty digestion.


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## Alexander_Hun (Jul 18, 2022)

Biom said:


> Sodium bicarbonate in melt.


Sodium bicarbonate, or natrium carbonate?


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## Biom (Jul 18, 2022)

Alexander_Hun said:


> Sodium bicarbonate, or natrium carbonate?


S b


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## Yggdrasil (Jul 18, 2022)

Biom said:


> S b


We use correct names for chemicals or formulas. 
Using the wrong chemicals can in certain cases lead to serious accidents or at least to unwanted reactions.


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## Biom (Jul 18, 2022)

Yggdrasil said:


> We use correct names for chemicals or formulas.
> Using the wrong chemicals can in certain cases lead to serious accidents or at least to unwanted reactions.


Sorry yes that's true


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## Alexander_Hun (Jul 18, 2022)

I usually take it for heartburn if there is nothing else at home  I asked to make sure I understood correctly


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## Biom (Jul 18, 2022)

Alexander_Hun said:


> I usually take it for heartburn if there is nothing else at home  I asked to make sure I understood correctly


Yes but if still have same problem .You have to refine again . Sodium bicarbonate can take some tarnish . but if there is more traces of other metal . you have to refine again


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## Alexander_Hun (Jul 19, 2022)

Hi, on the advice of many, I refined the gold again, the result is good! I boiled the gold dust in hydrochloric acid and then in distilled water several times.


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## Biom (Jul 19, 2022)

Alexander_Hun said:


> Hi, on the advice of many, I refined the gold again, the result is good! I boiled the gold dust in hydrochloric acid and then in distilled water several


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## Biom (Jul 19, 2022)

Great happy for you itb looks good . You can do more same steps good luck


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## Yggdrasil (Jul 19, 2022)

Alexander_Hun said:


> Hi, on the advice of many, I refined the gold again, the result is good! I boiled the gold dust in hydrochloric acid and then in distilled water several times.


Nice button, complete with a small dimple
Even the colour of the liquid and powder look good


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## Alexander_Hun (Jul 19, 2022)

Yggdrasil said:


> Nice button, complete with a small dimple
> Even the colour of the liquid and powder look good


Thanks, here is the self-made stannous chloride

View attachment 20220719_114619.mp4


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## Shark (Jul 19, 2022)

Very nice button!

Be very careful working with these acids inside, you need a fume hood at best. A fan in a window will help. 

While I feel it ruins the looks of clean gold a sign of good purity is how soft the gold is. Lay a piece of gold in the palm of your hand and rub your other hand across it one time. If it is fairly pure your skin will scratch very fine marks into the gold. Over time you will not need this method as you will see other signs.


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## Alexander_Hun (Jul 19, 2022)

Hi, I use this when I work with acid. I usually do a "water test" with gold. Specific gravity, volume, etc... Pretty accurate


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## Biom (Jul 19, 2022)

Good mask it's good to be safe . Just make sure you do this faaaaar away from kids family . No mistakes on safety .


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## Shark (Jul 19, 2022)

I would not trust that mask. 

It will not stop the fumes from being on your. Cloths, shoes or furniture and walls.


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## Biom (Jul 19, 2022)

Biom said:


> Good mask it's good to be safe . Just make sure you do this faaaaar away from kids family . No mistakes on safety .


Ones you start refining and that feeling of making gold fro A to Z . There is no going back .you will keep looking to make more . It's good hobby .but if you knew how to get more stuff .You will make a lot of profit . Good luck in Hungary I think there good opportunity to buy old jewelry .from yard sales thrift stores .


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## Alexander_Hun (Jul 19, 2022)

Biom said:


> Ones you start refining and that feeling of making gold fro A to Z . There is no going back .you will keep looking to make more . It's good hobby .but if you knew how to get more stuff .You will make a lot of profit . Good luck in Hungary I think there good opportunity to buy old jewelry .from yard sales thrift stores .


Hi, thanks, there is a lot of old Russian military equipment around here, with a lot of good materials.


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## Alexander_Hun (Jul 19, 2022)

Shark said:


> I would not trust that mask.
> 
> It will not stop the fumes from being on your. Cloths, shoes or furniture and walls.


Hi, the process takes place in the yard, exceptionally the video was made inside, but this is not typical, otherwise this is not part of the house, it is a workshop.


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## Biom (Jul 19, 2022)

Alexander_Hun said:


> Hi, thanks, there is a lot of old Russian military equipment around here, with a lot of good materials.


Great you may do good in other metals more then gold . Copper silver ....


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## Alexander_Hun (Jul 24, 2022)

Today find, crazy Russian relay


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## JATSLO (Jul 24, 2022)

Alexander_Hun said:


> 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?


Just trickle the nitric acid as the excess can redissolve the precipitant.


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## Alexander_Hun (Jul 26, 2022)

Hello!

I have noticed that since I have been using urea, the gold has been reduced differently. It becomes a very fine mud, which settles very, very slowly only to the bottom of the glass. After that, it is more difficult to deal with than if I had done the process without urea. But I'm afraid to work without urea...


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## Yggdrasil (Jul 26, 2022)

Alexander_Hun said:


> Hello!
> 
> I have noticed that since I have been using urea, the gold has been reduced differently. It becomes a very fine mud, which settles very, very slowly only to the bottom of the glass. After that, it is more difficult to deal with than if I had done the process without urea. But I'm afraid to work without urea...


Sorry mate, we do not recommend urea, that is a fertiliser that’s it, use Sulfamic acid at 70-80 C


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## Alexander_Hun (Jul 26, 2022)

Yggdrasil said:


> Sorry mate, we do not recommend urea, that is a fertiliser that’s it, use Sulfamic acid at 70-80 C


Hi!

Thanks for the reply! I ordered some of it, would you like to know how to use it? For AR in powder form as long as there is a reaction? Thanks


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