# I Have been having alot of trouble with aqua regia



## Anonymous (Jul 30, 2007)

I have attempted a few times to recover gold from gold fingers,processors,and header pins without much luck. I have been buying my chems premade from a supplier called Shor International in NY.
The directions were vague at best, but being a reasonably intelligent person I thought it wasnt beyond me.

Well much to my dismay I have realized there are as many ways to do this as there are people it seems. After many chemical burns (my clumsiness lol) and lung fulls of hydrochloric acid lol, I found this forum and for the first time since I started this endeavor I fell I am actually finding the information I need .

LazerSteves site is the best I have ever seen and I really appreciate this forum and his site. Most people are tight lipped or just want your money ,as they try to sell you the plans for somthing they actually havent done themselves.

Great work guys and much appreciation from guys like me!

I have several gallons of aqua regia that i have dissolved a good amount of gold and other metals into. I have adjusted the ph with urea and attempted to add the preipitant but ...it seems to fizz then sinks happily to the bottom of the solution(not gold dust/mud). the white precipitant is all that is there. This solution is a very dark emerald green ( I used Sub zero and muriatic acid). Is there an alternative method to get the gold back or have i just learned a costly mistake?

Any ideas or help would be greatly appreciated, Thanks in advance.

Ken


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## aflacglobal (Jul 30, 2007)

Welcome to the forum. Sounds like a problem there. Might want to bail out and start over with the information here on the forum. Just forget you ever heard that word shor. :wink: Never fear if you have the acid you still have the gold. Here is the method harold has described. Keep the steel in there until the solution tests barren for precious metals by using 
Stannous Chloride. :arrow: http://goldrefiningforum.com/~goldrefi//phpBB3/viewtopic.php?t=562&start=0&postdays=0&postorder=asc&highlight=


Bail out from AR :arrow: 

When you recover values on scrap steel, even the resulting copper gets involved in precipitating the gold, platinum or other values. In the end, everything (of value) will have precipitated on the steel and the copper. You don't get selective precipitation by this method, it's strictly a bail-out to recover values such that you can start a different process instead of tossing them.


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## Harold_V (Jul 30, 2007)

Ken,

I shake my head in wonder as I read about guys dissolving all the metals along with the gold. You really complicate things when you do----and there's no real benefit in doing so unless the base metals don't lend themselves to dissolution by common acids or alternatives. Even then, if you're stuck with using AR, you can still eliminate the vast majority of the valueless materials before attempting to recover your gold by using good practice. It's easy to do if you're interested in talking about it. 

The chance of precipitating gold of decent quality diminish quickly when you dissolve gold with a large amount of base metal, regardless of the type. I'd encourage you to explore methods of stripping the gold, or to eliminate the base metals before dissolving gold. 

When you've come to terms with that idea, you should then explore the proper washing of your gold after precipitation, to improve its quality. Do not rely on melting and fluxing to improve the quality-you'll be sadly disappointed. 

Welcome to the forum.

Harold


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## Anonymous (Jul 30, 2007)

I appreciate the quick response and the information. I am really studying all this very intently, i guess i just have to realize how it all works. You guys here are a great help and I have been considering using lazersteves method of peroxide stripping . 

One question I do have though is...After stripping the gold into the peroxide acid bath and recovering the foils, Is any of the gold suspended in the bath that is left behind and how do you recover that?

Thanks to all in advance,

Ken


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## Harold_V (Jul 30, 2007)

Considering I never used that particular process, I'll defer to Steve, who has considerable experience in the field. 

Harold


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## aflacglobal (Jul 30, 2007)

One question I do have though is...After stripping the gold into the peroxide acid bath and recovering the foils, Is any of the gold suspended in the bath that is left behind and how do you recover that? 

In the AP method the acid ( muiratic ) used will only dissolve the base metals that the gold is attached to. It should not dissolve the gold. once you get the foils separated from the base metal you have a much cleaner material to work with (99 %). 

Then you can move on to Auric chloride. That would be Muriatic acid and bleach. This will generate the chlorine need to dissolve the gold into solution. You can then drop with smb. 

But the plot thickens. Make sure you do the proper washes after this ( The AR trash ). Harold has posted somewhere on the forum the proper recipe for this . This step is just as important as any. The step after that is melting. Their is a lot to this step also.

Oh yeah, Once you get the metals you have out that AR mix make sure you wash them gooooood. If you carry any of the nitric over to the AP process you stand a chance of dissolving some gold back into the AP mix.


I think that's it ? If not someone will correct me.

Throw the cat a bone.


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## lazersteve (Jul 30, 2007)

Ken,

Typically, the dissolved base metals will push the bulk of the gold out of the solution as a fine black powder. What remains dissolved in the solution can be dropped with SMB dissolved in water. As Ralph mentioned it will need a good cleaning due to the amount of base metals in the mother liquor.

A few additional comments about the HCl-Cl method of dissolving gold and cleanup. If you follow my cleaning directions for the foils in the Acid Peroxide tutorial, then dissolve the clean foils in HCl-Cl the final cleanup can be shortened to just a hot HCl rinses followed by a few hot water rinses of the powder. The main need for the repeated cleanings Ralph mentioned occur when the gold powder is dropped from dirty solutions. If the dissolved gold solution is deep golden yellow, there is not much that can contaminate your dropped gold. 

Steve


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## Dog Biscuit (Jul 30, 2007)

I have experienced gold going into solution using AP. In processing a batch of pins, I applied heat to the mix. Gold flake return was much less than anticipated, and I checked the solution with stannous chloride.. The solution tested positive, and I was able to recover my gold with sodium sulfite.


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## aflacglobal (Jul 30, 2007)

The main need for the repeated cleanings Ralph mentioned occur when the gold powder is dropped from dirty solutions.

That's it. Sometimes i just get people as confused as me. That's the point i was getting at. Thanks Steve.



I have experienced gold going into solution using AP. In processing a batch of pins, I applied heat to the mix. Gold flake return was much less than anticipated, and I checked the solution with stannous chloride.. The solution tested positive, and I was able to recover my gold with sodium sulfite.

Any idea of how much may have dissolved. Say 5%, 25%.
I can see a little maybe with heat, but i would think it would self drop on cooling. I didn't think gold would dissolve to any great extent in muratic.

I could be wrong. I'm asking because i'm learning to.


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## badastro (Jul 30, 2007)

Here are some chemistry lessons: :twisted: :twisted: :twisted: 

Any solution containing chlorine ions is capable of dissolving gold. 

Oxygen from the air can get absorbed into HCl and oxidize gold. The gold ions then form complexes with the chlorine ions to give auric chloride.

The truth is a very tiny amount of gold will dissolve in HCl until all available oxidizers are used up. This amount may not be detectable. 

Acid peroxide is just a weak form of aqua regia. Aqua regia works by having the nitrate ion oxidize gold as ions and allowing chloride ions to form complexes. This is why you don't need nitric acid to make a gold dissolving solution: just use sodium nitrate (which is an oxidizer) for poor man's AR. Those brown fumes come from the nitrate ions being reduced by the gold as the nitrate ion gives up oxygen to become NO.

Acid peroxide is the same idea. Instead of nitrate as an oxidizer, you're using hydrogen peroxide, which is also a powerful oxidizer. The hydrogen peroxide oxidizes the gold and the chloride ions form soluble complexes. Also happening is the dissolution of oxygen into the acid, which helps dissolve gold.

Nitric acid will actually dissolve a tiny undetectable amount of gold into ions, but since gold will not form soluble compounds with the nitrate ion, the gold does not continue to dissolve.

The reason why nitric acid will dissolve base metals such as copper very fast while hydrochloric acid will not dissolve it fast is because HCl is a non-oxidizing acid.

HCl cannont oxidize copper metal into an ion so the copper stays intact. It will react with oxides of copper forming water with the oxygen and hydrogen ion leaving a copper ion to form a compound with the chloride ion. If there is oxygen in the air that can dissolve into the acid, then that dissolved oxygen can oxidize the copper which then forms compounds with the acid. In effect, the acid makes the copper corrode from the air faster because the chlorine is stripping away the protective oxide layer.

Nitric acid is different because it can oxidize copper. The nitrate ion plays a dual role. Free nitrate ions give up oxygen to oxidize copper. The oxidation of copper simultaneously reduces the nitrate ion into nitrogen monoxide gas. Free hydrogen ions combine with oxygen to form water and free nitrate ions combine with the copper ion to form copper nitrate.

The reason why AP is prefered over AR is because it doesn't give off horrible fumes. Gold is least likely to dissolve in both AR and AP, but each metal does not dissolve precisely sequentially. There is some overlap. Galvanic action can help make the process more sequential, but not everything is electrically connected so it doesn't happen effectively.

You can in theory dissolve base metals only with aqua regia by controling the amount of nitrate ions you put into the acid. The reason why AR dissolves everything is because we make it such that it will dissolve everything, but if we limit the amount of nitric acid or NaNO3, then we mimick the effect that acid peroxide does.

AP will dissolve everything like AR does if and only if you put in wayyyyyyyy too much peroxide without diluting it too far. It will take a long time but it will happen.

When an AP batch is done, the reason why gold flakes remain is because the oxidizer is all used up, and gold chloride displaces base metals and gets deposited as a black powdery film.

MEOW


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## aflacglobal (Jul 30, 2007)

Dam, your good. Thanks for the lesson. You have actually given me an idea. :idea: Now i understand it. 

Thanks. :wink: 


Your post just went into my forum book. 

Ahhhhhh. The nitric is the oxidizer that is added to the HCI to drive the reaction in AR. Dam how i miss the simple things. lol


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## aflacglobal (Jul 30, 2007)

Ken, 
Heres the thread on acid washes. Getting pure gold (shining) :arrow: 
http://goldrefiningforum.com/~goldrefi//phpBB3/viewtopic.php?t=325&start=0&postdays=0&postorder=asc&highlight=


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## aflacglobal (Jul 30, 2007)

:idea: :idea: :idea: 


Teabone, 

By using the first method (peroxide acid) to dissolve the just base metals and not the gold, you will end up with a cleaner gold powder when it is dropped out of the second solvent ( HCl-Cl or AR ). As you have read time and time again on the forum, the purest gold is that which is first throughly cleaned of base metals, then dissolved and precipitated. A second cycle of cleaning and precipitation yields even higher quality gold. If you were to attack the gold and base metals outright using the acid peroxide bath the gold and copper laden liquid would drop gold when treated with SMB, But the gold would not be as pure as it would be if it was separated from the base metals first.

In practice you can remove the base metals with many techniques, including using the HCl-Cl to remove the base metal first. The idea behind using the peroxide acid to strip the base metals as a first step comes from the fact that the CuCl2 formed from the acid peroxide attacking copper is a really good solvent for Copper coupled with the fact that the same mix is only a fair solvent for gold ( 1/45 the dissolution rate of HCl-Cl and 1/450 the dissolution rate of AR). In short, the acid peroxide ratio is such that it is meant to catalyze the formation of CuCl2, not for the dissolving of the gold. By performing the acid peroxide reaction at room temperature, the likelyhood that the gold will be dissolved is reduced even further. 

This duality of function of the acid peroxide method is leading me to believe that I should modify it yet again to be the Copper Chloride method. This way it will clearly be tuned to attacking the copper cladding and not the gold. The new and improved method will have the added benefit of having zero acidic fumes. I'm still researching the best solvent for copper when safety, speed, efficiency, and reusablity are factors. 

Steve


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## lazersteve (Jul 30, 2007)

Astro,

Excellent description of the processes. 

I try to think of the chlorine as the "active ingredient" that dissolves the gold. Without it you can't form the soluble Auric Chloride. The oxidizer can be any chemical oxidizer or even electric current. The chlorine can also be produced from a chloride compound such as sodium chloride. The trick is to generate the in situ nanscent chlorine ion (Cl-).


Great stuff Astro!


Steve


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## Anonymous (Jul 30, 2007)

Most of what you excellent chemists has posted is excellent stuff that is beginning to give me a real understanding of the process. BRAVO Guys!
Finally some intelligent people with real answers to my questions.

Let me see if I understand what I have read thus far........

Basically If I use the hydrochloric acid and peroxide as an initial wash or AP as you all put it, then i will end up degrading the underlying and surrounding base metals from the gold leaving only the gold in solid form with very little losses in the actual solution. 

then cleanse the gold foils or flakes in muratic and finally water to remove all traces of the original chems.

then create a second solution of muratic/hydrochloric acid and bleach as an oxidizer to break the gold down into this solution as a fine gold color fluid.

then use liquified smb introduced to the gold solution to settle the gold dust to the bottom of the same container, rinse then go to the task of melting the gold.

Is this correct? If so sounds alot easier than AR

You guys are great and have the answers here glad I found this forum.

Ken


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## aflacglobal (Jul 30, 2007)

Sounds good in process.  

Yes, i think you are getting it. Me to. :wink: That's the way i have got it figured. You will have to excuse me i tend to get things all confused. I just have to know everthing that applies to the process. (Then) :shock: I come up with these crazy theories of mine.


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## lazersteve (Jul 30, 2007)

When the light finally goes on it's all very simple.


How did you find the forum Ken?


Steve


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