# Aerating / Oxygenating Spent Acid Peroxide Solution



## junkelly (Aug 2, 2007)

I am under the impression that with the Acid-Peroxide method, the main point of the peroxide is to supply oxygen. I am under the impression that this can be done without peroxide by bubbling air through the solution. I am under the impression that, up to a point, the solution can be 'regenerated' and made active again by the addition of oxygen. Please correct me if I am wrong in these assumptions.

So I was wondering if this would be as simple as using a cheap aquarium 'air pump' (not a submersible water pump). These air pumps run quietly, must be situated above the water level, and have an outlet that fits a 1/4inch vinyl tube, which attaches to an air stone, or 'bubbler'.

Rather than asking y'all in advance, I decided to try it out on my own AP solution. This is my first batch ever, and is small in size, roughly 2-3 cups. It had been stagnant for ~24 hours and the solution was dark in color. I assumed that if the bubbling reactivated the solution, I would notice a prominent lightening of the color. I bubbled for roughly two minutes, while gently stirring, and did not notice any color change. I did not use an airstone--simply the end of the vinyl tube.

I later added a splash of H2O2 and HCl, at which point the color lightened.

What I learned: The clear vinyl tubing seemed to be unharmed. The 'splatter' from the bubbles was greater than I anticipated.
What I still don't know: Is this a viable method for regenerating the solution?

I am wondering if my assumption that simply bubbling 'air' through the solution will work, and what methods others have for regenerating their solutions.

I have not seen any reference to this in other posts. (Or perhaps they were over my head.) I was hoping to contribute to the forum by saying 'Look at this method that I just successfully tried!', but that will wait for another day...

-junkelly


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## lazersteve (Aug 2, 2007)

Junkelly,

Regeneration of the AP using a bubbler is covered in the 'CuCl2 as an Etchant' document on my website, http://www.goldrecovery.us , under the regeneration section of the document. You will learn a lot if you read this entire document.

It takes longer than just a few hours. I have regenerated 1 1/2 gallons of solution in 36 hours using an ordinary aquarium bubbler with stone. The stones don't hold up to the acid, so a custom PVC bubbler rig is a big plus. The PVC bubbler will work faster. Splattering is handled by loosely covering the reaction bucket. Acid concentration is important to the regeneration process.

Steve


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## hilld2000 (Aug 3, 2007)

I would imagine another consideration would be the size of the bubbles, the smaller the bubbles the better, but eve with the tiniest of bubbles most of the air would not get dissolved.

In addition, most of the air would be nitrogen and give no benefit...
About 1/5th being oxygen...

With H2O2, the oxygen is already in solution and has nowehere to escape to.
I think I may experiment with this method myself since buying h2o2 in the UK immediately labels me as a terrorist! :roll: 

as does buying NaSO4, KNO4 etc....


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## Platdigger (Aug 3, 2007)

Since this works, I am curious if it is the oxygen or the nitrogen that is having the most effect. Think that perhaps a week aqu regia is formed because of the nitrogen adding nitrates to the solution? I guess a guy could try pure oxygen to see if it has the same effect. Ideas?
Randy


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## lazersteve (Aug 3, 2007)

Here's some more info for those that are interested in regeneration of the Cu++

Regeneration of AP

Steve


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## junkelly (Aug 3, 2007)

Thanks for the links, Steve. Thank you also for your videos and written advice--they are very helpful. I previously read the PDF on your site. I guess I read only enough to get the 'big picture', and didn't notice the details of how long it takes to regenerate the mix.

Like I said, I am only beginning, so it will take some time before I have enough solution to warrant this. When the time comes, I will make an air manifold and let it run for at least 24 hours. I assume that it will be as simple as capping (perhaps melting) the end of the air line and poking or drilling numerous small holes in the tubing. I do not wish to purchase an 'air stone' if it will not hold up to the acid.

Another factor to increase the reaction is the height of the vessel. All other things being equal, air bubbling through a tall, narrow container will have more chances to react than air bubbling in a wide, shallow container.

I am not sure if Nitrogen goes into solution. I am under the impression that it is 'inert'. I think that a lot of sealed packaging that seems to be filled with air is actually filled with 100% Nitrogen, to keep the contents from reacting with anything.

I am still wondering if other members regularly regenerate their solution, or simply keep adding the HCL & H2O2, and then dispose of it when it gets to be too much to handle.

-junkelly


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## lazersteve (Aug 3, 2007)

Junkelly,

I reuse portions of mine and dispose of the rest. The solution grows in volume as copper is absorbed into the mix. I dispose of the excess. Proper disposal is eventually a requirement no matter whether you regenerate the mix or not. 

Steve


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