# Aqua Regia vs. Acid Peroxide.



## NuggetHuntingFool (Jul 16, 2008)

I'm curious as to why you guys use Acid Peroxide instead of Aqua Regia in the first step (most of you).

It seems to me that Aqua Regia skips a step in the process by dissolving the gold in step #1. Whereas with Acid Peroxide you have to strip the foils, then dissolve them with Acid/Chlorine in step #2.


Is it a safety thing?
Cost?
Efficiency??

I'm still learning, but I hope this isn't too "green" of a question.

Thanks


----------



## NuggetHuntingFool (Jul 16, 2008)

Sorry moderators. I didn't realize there was a "Chemical Processes" section that would have been more appropriate for this question.

Please move if you desire.

Thanks.


----------



## lazersteve (Jul 16, 2008)

NHF,

AP removes the base metals and leaves the majority of the gold intact. This makes for cleaner gold once it is dissolved and uses zero nitric acid (expensive and hazardous). It takes a lot less AR (or HCl-Cl ) to dissolve the small amount of foils after removing the base metals and provides for cleaner gold precipitations.

Steve


----------



## Harold_V (Jul 16, 2008)

NuggetHuntingFool said:


> Is it a safety thing?


Smart people don't recover gold with AR unless there's a good reason to do so. Eliminating base metals is always in your best interest, and that normally is not accomplished with AR. If you were to recover values from non-metallic objects, where the substrate does not become a part of the solution, AR is generally acceptable. When values are plated over base metals, it's not a good idea at all. 



> Cost?


Assuming you are able to buy nitric to make AR-----cost is generally not a factor. As much acid, overall, will be consumed by dissolving with AR directly as compared to eliminating base metals with nitric (or HCl) prior to dissolving the values. As Steve alluded, the benefits of doing so are achieving a much higher level of purity from the precipitated gold. Even with a selective reagent, gold that precipitates has a tendency to drag down anything that is in solution. When precipitating from solutions that are heavily laden with base metals, the end result is less than decent quality gold----even after washing well with an accepted washing procedure. There is no better way to insure high quality than to minimize garbage in solution. 



> Efficiency??


Likely not a major factor, although gold that is dissolved with considerable garbage often filters poorly. By incinerating at the appropriate time, and doing preliminary processing by acid, either HCl or nitric, depending on the nature of the material, the remaining solids (the values) will usually be far easier to filter after dissolution. 



> I'm still learning, but I hope this isn't too "green" of a question.



Not in my opinion. As you refine, you'll recognize problem areas that may be difficult to avoid, but with experience and a good understanding of the refining process, you'll generally learn methods that will eliminate, or at least minimize, given problems. The preliminary washes are a good example. A solution that may have been contaminated with tin can be very troublesome to filter, yet incineration and a preliminary wash in HCl eliminates the problem entirely. Beginners don't know that, and generally don't have enough imagination to solve the problem. 

Harold


----------



## NuggetHuntingFool (Jul 16, 2008)

Gentlemen,

Thanks for the replies. You've cleared up a lot of questions and curiosities in one post for me.

So basically when I'm panning and in my black sands I'll run AP through them so I can dissolve the contaminants and leave mostly precious metals (hopefully)?

Another question if you would.

Does HCL/Bleach dissolve other precious metals, or only gold?

Does it do Pt, Ag, Au?

Or if I was on the hunt for Pt for instance would I require AR?

By the way. I downloaded that Modern Marvels episode about acids... totally awesome. All I ask is one barrel-full of that yellow Pt paste! 

Thanks,
I appreciate the help.


----------



## Oz (Jul 16, 2008)

As to “Does HCL/Bleach dissolve other precious metals, or only gold?” Yes but it will give you silver chloride. Also on the PGMs it depends what forms they are in.

“Or if I was on the hunt for Pt for instance would I require AR?” if Ag is present again you will get silver chloride.


----------



## NuggetHuntingFool (Jul 16, 2008)

So basically the silver is dissolved first in each instance of HCL/Chlorine and AR?

If I mad a mixture of gold and silver the chemicals would dissolve the silver first. Once it's finished with the silver will it start on the gold or will it leave the gold alone?

Will it dissolve both at the same time?

What if you had Au, Ag, and PGM's? How would you guys attack them, let's say for instance that there weren't other contaminants, just the three and you only had acids at your disposal.

Thanks,
Great info.


----------



## Anonymous (Jul 16, 2008)

I tried chemicals with black sands, all I can say is it takes a lot of acids to 
dissolve that stuff. It did not work out for me, but, you may have a richer source.


----------



## Harold_V (Jul 17, 2008)

NuggetHuntingFool said:


> So basically the silver is dissolved first in each instance of HCL/Chlorine and AR?
> 
> If I mad a mixture of gold and silver the chemicals would dissolve the silver first. Once it's finished with the silver will it start on the gold or will it leave the gold alone?


In both instances, silver will NOT dissolve. If it is present in great enough volume, _nothing_ will dissolve. You can not dissolve silver with a chloride. It will yield silver chloride, if anything. Generally it does nothing. 

What if you had Au, Ag, and PGM's? How would you guys attack them, let's say for instance that there weren't other contaminants, just the three and you only had acids at your disposal.

Thanks,
Great info.[/quote]
You'd be in trouble. Once silver and the platinum metals mix, they will dissolve along with silver, using dilute nitric acid----so separating them can be involved. They are generally best recovered when parting silver in a silver cell. 

READ HOKE! I don't care if you buy a copy or download a copy-----do it before you proceed further. These are fundamental things you should understand before refining. It can prove to be valuable information, preventing you from tossing values, or understanding why your metal isn't doing what you hoped it would. 

Harold


----------



## NuggetHuntingFool (Jul 17, 2008)

Harold, I actually clicked on your link and my copy arrived via UPS today .

I'm looking forward to the read.


Thanks


----------



## Harold_V (Jul 17, 2008)

Very good!

Much of what you want to know will start making sense. Best of all, you'll be able to ask questions that make sense because you'll have a better understanding. 

I'd enjoy a report on your opinion of the book. Others may need the shove to make the choice to buy. They might appreciate comments beyond mine in that regard. I have no doubt many think I profit from the book. I do not. I am not affiliated with the book, or its sales, in any way. 

Harold


----------



## NuggetHuntingFool (Jul 17, 2008)

You might as well post more links to other good books in your signature too... You're a huge wealth of knowledge.

I will post an opinion of the book when I've read some more.

As far as making money from the book... it wouldn't surprise me if your knowledge has made you millions already...

Thanks.


----------



## Anonymous (Jul 19, 2008)

> NHF,
> 
> AP removes the base metals and leaves the majority of the gold intact. This makes for cleaner gold once it is dissolved and uses zero nitric acid (expensive and hazardous). It takes a lot less AR (or HCl-Cl ) to dissolve the small amount of foils after removing the base metals and provides for cleaner gold precipitations.
> 
> Steve



If I may add a quick question to clarify this conversation in my mine.

THE AP solution will not dissolve gold only base metals.

so I am to assume the greenish liquid i have after treating my gold pins is waste?


----------



## arthur kierski (Jul 19, 2008)

peroxide +hcl dissolves gold, pt and pd ---i do it almost daily


----------



## NuggetHuntingFool (Jul 19, 2008)

Are you sure AP dissolves gold??

From what I've seen it doesn't.


Steve uses AP in his videos and the gold remains in solid-form. However, the base metals are another story!


??????????


----------



## Anonymous (Jul 19, 2008)

I think he ment HCL and clorox. Acidic peroxide only seams to strip the copper underneath.

This still leaves my question hanging. Is my green solution full of foils waste? Or should I keep it in some hope that values lie within?

should it be tossed after filtering?


----------



## NuggetHuntingFool (Jul 19, 2008)

Well if it dissolves copper then it might just be of some value eventually.

I've been reading Hoke's book and she states you can leave your filter papers to dry for recovery of material at a later date.

I guess if you eventually build up a good supply of copper-infused filters it could be worthwhile. No?


I'm not sure though, but I suppose one of the high-ups in this forum will give us a good answer.


----------



## Scott2357 (Jul 19, 2008)

If there is too much peroxide(use 3% to be safe) or solution is too warm, gold will dissolve.


----------



## NuggetHuntingFool (Jul 19, 2008)

Which just proves how little I really do know!


----------



## Harold_V (Jul 19, 2008)

Jdwisnie said:


> should it be tossed after filtering?



When handling solutions that have contained precious metals, be they dissolved or not, nothing should be discarded without first testing with stannous chloride that is known to be active. A follow-up test with salt or HCl for traces of silver is also a good idea. Even well experienced refiners exercise these tests. 

Harold


----------



## Irons (Jul 19, 2008)

arthur kierski said:


> peroxide +hcl dissolves gold, pt and pd ---i do it almost daily



I agree. Pd will dissolve in H2S04, HCl and Nitric. If there's enough Pd, it will generate Cl on its own by stripping the Hydrogen from HCl and that will dissolve almost anything in time.


Every source of material is different and each case has to be examined on an individual basis. Working with ores is totally different than working with the metals in refined form.


----------



## arthur kierski (Jul 19, 2008)

instead of using h202 at 3% i use at 30%(100volumes -)
example 100cc of hcl , put the metals or powder to dissolve and then 50cc h2o2 (100volumes) slowly ---the reaction does not needs heat because it is quite violent---when fizzing stops , heat the solution to eliminate exceess o2----i repeat, i do it almost every day


----------



## NuggetHuntingFool (Jul 19, 2008)

I find it's the strangest thing. The method you use to get rid of base metals that doesn't dissolve gold. Then a little heat, or higher concentrations and it suddenly dissolves the gold and not the base metals...


So many different ways of attacking so many different combinations of materials.


It's like this takes a lifetime to learn because of all of the different variables. I can see why you guys like it. It's like a new mystery with each new material you process.


----------



## Harold_V (Jul 20, 2008)

NuggetHuntingFool said:


> I find it's the strangest thing. The method you use to get rid of base metals that doesn't dissolve gold. Then a little heat, or higher concentrations and it suddenly dissolves the gold and not the base metals...



That may not be what's happening. Don't lose sight of the fact that precious metals in solution are easily cemented (precipitated) by replacing them with the base metals that have not been dissolved. It may not happen initially, but as the solution loses its ability to dissolve the values, the conversion will take place. Armed with this idea, there are times when you can use the process to advantage. 

You'll have to rely on one of the chemists to word this so it makes chemical sense ------I have no idea exactly how it works---I just know it does. 

Harold


----------



## Irons (Jul 20, 2008)

NuggetHuntingFool said:


> I find it's the strangest thing. The method you use to get rid of base metals that doesn't dissolve gold. Then a little heat, or higher concentrations and it suddenly dissolves the gold and not the base metals...
> 
> 
> So many different ways of attacking so many different combinations of materials.
> ...



PGMs have a strong affinity for Hydrogen, they act as catalysts, sometimes to your disadvantage and concentration, temperature and pressure all play a factor.

Learn the electrochemical series. It plays a very important role.


----------



## arthur kierski (Jul 20, 2008)

both ar and ap dissolve pms and base metals---both forms silver chloride as a white curdy powder---the difference is the various concentrations of the reagents and heat---for instance,cold ar does not dissolve pt--but dissolves au and pd----ap with 3%peroxide does not dissolve gold----
pdo +rho will be dissolved only if you reduce these oxides to metal---etc, etc---for instance in hokes book she reduces pdo to pd by leaving the pdo in hcl---others reduce with sodium formate in a carbonated solution
black sand (i never done anything with it) might have iron which must be eliminated before an ar or ap attack or it will consume all the hcl first by dissolving this iron---might have silicates which might need naoh or hf to dissolve ---etc


----------



## NuggetHuntingFool (Jul 20, 2008)

After hearing the stories and dangers I don't even want to go near Hydrofluoric Acid.

I like my bones and want to keep them where they are.


----------



## arthur kierski (Jul 20, 2008)

after all my explanation--you take a small item out of it and says that you do not use or is afraid of using it---i did not tell you to use hf or naoh in black sand---i told you that i do not have experience with black sands---i just wanted to tell you that you can extract precious metals with ap or ar --depending on heat and concentrations of the various reagents


----------



## Anonymous (Jul 20, 2008)

@ Harold/Kumar(A.K) Even though I somewhat hijacked this thread you guys were a big help and super informitive. 

@Nugs I hope I didn't derail the answers you were seaking.


Thanks again.


----------



## NuggetHuntingFool (Jul 21, 2008)

The thread has been very helpful.

I appreciate the help for sure.

I was just making a joke about the HF Acid, and still wouldn't want to go near it!

I should have some black sands by the end of Fall. Hopefully they'll have PM's for me to chase.

Thanks


----------

