# Fun with Concentrated Hydrogen Peroxide and Pins



## Rag and Bone (Apr 12, 2008)

I had a surprising success with pins in HCl and concentrated 36% H2O2.

6oz. gold plated pins (low grade)
250ml HCl 31%
40ml H2O2 36%

Added HCl to pins in a beaker followed by H2O2. Immediate vigorous fizzing and bubbling. The fumes burnt my eyes despite the goggles. The pins where the H2O2 hit were stripped immediately. The solution turned dark within 30 seconds. The pins were stripped down to copper within a few minutes with just a few patches of gold remaining. I let the fumes die down and filtered out the gold. I was done in a half hour. The yield was pretty pathetic. I wasn't able to test the solution for dissolved gold (the stannous went bad).


In retrospect I used way too much H2O2. The concentrated stuff really packs a punch. I highly recommend it to the AP crowd. 

Next time I'll try high grade pins with gradual additions of H2O2.


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## geekzilla (Apr 15, 2008)

After watching Steves video on the AP process with gold fingers, I too began to wonder if a more concentrated HP solution would yield quicker results. Thanks for trying it out and posting your results.

Incidentally, I have found an online supplier for H202 that has flat rate shipping to anywhere in the US for $9.95 (they also sell HCl)! Here is the link:

http://www.pondepot.com/index.asp?PageAction=VIEWPROD&ProdID=3161


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## Rag and Bone (Apr 15, 2008)

I just started using concentrated H2O2. The results have been very pleasing. I will never use the weak stuff again. Concentrated ends up being cheaper, less garbage (one jug rather than dozens of small ones), faster results, better penetration on persistent plating, smaller volumes of spent acid. I love it!


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## Irons (Apr 16, 2008)

One has to be careful not to add too much Hydrogen Peroxide to HCl. When the solution starts boiling off Cl2 gas, it's time to back off. Chlorine is toxic and what boils off is wasted.

Once you see tiny bubbles rising to the surface, the H2O2 is doing its job, anything more is a waste of money.


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## P_CARROLL (Apr 16, 2008)

Did any of the gold go into solution or was just the plating stripped off?


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## Rag and Bone (Apr 16, 2008)

I suspect a good deal of it went into solution. The stannous went bad so I couldn't check. The gold that I did collect was extremely fine powder mixed with very fine red copper.I added the solution to some fingers in AP so it should come out in the wash. Like I said, I used way too much H2O2. It got me thinking though...

What if you mixed up some very strong AP and just flash stripped off the plating on pins, plated jewelry, cpus etc. ???


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## lazersteve (Apr 16, 2008)

I have several gallons of 35% H2O2, but I still use the weaker 3% stuff in my AP. The main reason is for the extra water. The water allows the Copper II Chloride to become mobile in the solution and keeps the rejuvenation cycle going. The other main problem with the concentrated stuff is that you end up dissolving your gold along with the base metals due to the excessive amount of chlorine produced.

If you think about the etching reaction you will realize that the active ingredient is the copper II chloride, not the peroxide or the muriatic acid. With this in mind the water is necessary to allow the exchange of the copper metal ions in liquid form. If the solution becomes saturated due to lack of solvent (water), the copper won't convert to from the deactivated (and insoluble form) of copper I chloride back to the soluble desirable form (copper II chloride). If you find a lot of off white to gray colored sludge in your batches you are producing copper I chloride. It becomes discolored by the saturated etching solution which appear very dark brown in color and very thick.

Here's the overview of the chemistry:



pcbfab.com said:


> Hydrogen Peroxide as a Replenisher
> 
> The Hydrogen Peroxide H202 system of replenishing has been unpopular in the PCB industry, for no outstanding reason, but not in the closely related Photo-Chemical Milling industry. Perhaps the real reason why it is not popular, is that a reliable control system, for both components required to replenish the system, Hydrogen Peroxide, and Hydrochloric Acid, has only recently become available. Previously, it was probable that those people who took on the challenge of devising their own control system would likely have chosen the least expensive, and easiest system to control replenishment system, which is the Chlorine system. The overall etch/replenishment reaction for Hydrogen Peroxide is:
> 
> ...



I find the extra water is to an extent is helping, not harming. I think the optimal amount of water is just enough to hold the copper II chloride that you need to etch the proper amount of copper off of the scrap.


Steve


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## Rag and Bone (Apr 16, 2008)

Wow. I completely misunderstood the AP process. I still don't fully understand it even after reading Lazersteves well written explanation (no surprise I failed Chem 101). 

So, if copper II chloride is the active ingredient, will the AP process cease to work in the absence of copper?


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## lazersteve (Apr 17, 2008)

Rag,

No. AP will still work on some base metals and even on gold due to the free chlorine that is formed when peroxide reacts with the muriatic.

Have you read the copper chloride document on my website?


Steve


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## Art Corbit (Apr 20, 2008)

I guess I did something wrong. I put some pins and some chopped up board in HCL and Peroxide and got no reaction. No fizz only a small bubble now and then. However I was using the 3% peroxide you get at the drug store. I put about half as much Peroxide as I did HCL and still only a very light reaction. In the pins the acid is slowly turning yellow like the gold is dissolving. I didn't intend to do that. The acid on the boards is turning a light green.

Art


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## Rag and Bone (Apr 20, 2008)

Art,
The reaction is slower with 3% H2O2. It can take days with fingers and longer with pins or cpus. Some pins don't dissolve very well in AP. It's good to do a small test batch to see if they will strip properly. To test, I put a couple pins in a petri dish with a small amount of AP. 

What kind of boards are you working with?


I'm wary to give advice on the subject. Steve and others are more knowledgable. I have achieved good results with AP but I don't fully understand the chemistry behind it.


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## Art Corbit (Apr 20, 2008)

The boards are out of phone systems. They are plated a lot heavier than the normal PC or card. I finally put everything in a crock pot and heated it up but now it looks like it is dissolving the gold and everything else. I wouldn't think HCL and Peroxid would dissolve Gold but maybe it will. I had to put about half as much Peroxid as I did the HCL to get any reaction at all. Then there was only a very few small bubbles. I have a lot of it to do so looks like I have got to make a trip to Tulsa to get some more Nitric. I sure thank you for your reply though.

Art


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## Anonymous (Apr 20, 2008)

Art, I only add a little peroxide to get started then when the solution is dark green add some more it will turn to a emerald like much liter green right before your eyes and it will leave your gold alone if you do not add to much peroxide at a time.


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## Art Corbit (Apr 20, 2008)

Mine wouldn't do anything untill I put a lot of peroxide in it. When I poured the HCL on it nothing at all happened. The caid stayed clear for several minutes and then you could see a real light color starting to apear. That was after I had alreadt added the Peroxide. I just went out and checked it and the gold is all gone but the copper is still there. I doubt if there is any way to drop the gold out of the HCL/Peroxide.

Art


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## Anonymous (Apr 20, 2008)

Art, 
I do not know how your gold could be insolution and the copper not, copper is used by some guys to precipated gold. 

I have limited experience only a few months put I do the process with HCL and peroxide and never had my gold react and leave the copper.

If you do not throw anything away you have not lost any gold.

I am sure that someone with more knowledge will be alone to help you.


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## Rag and Bone (Apr 20, 2008)

What color is the solution now?


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## Art Corbit (Apr 20, 2008)

I still have the acid. If all else fails I guess I can pour it through some carbon. It really isn't enough to get upset about. I ran a small amount just to try the HCL/Peroxide method. I still don't understand why it wouldn't do much of anything untill I heated it. Then most of the copper still there and all the gold in solution really puzzled me. I'll try to find some way to get the gold out of solution. Needless to say I'm not very impressed with the HCL/Peroxide method.

Art


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## Art Corbit (Apr 20, 2008)

The solution is green. The pins it was a yellow green.The boards was real dark green from the coating on the boards.

Art


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## Rag and Bone (Apr 20, 2008)

I don't know what the problem was. If you are putting entire boards in the solution you can expect all sorts of complications.


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## lazersteve (Apr 21, 2008)

Art,

You should keep your scrap types separated when processing with AP.

SMB will drop dissolved gold from AP.

Start with small batches and learn the process. I use it all the time and have excellent results with no heat.


Do you have some photos of the mix?

Steve


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## Art Corbit (Apr 21, 2008)

Hi Steve,

Please excuse a couple or four stupid questions here. Exactly what do you mean by keeping my scrap separated? Don't mix the boards with pins or fingers or what? I also need to know what you mean by "AP & SMB" I think I know what the SMB is but not sure.

I didn't get any pictures but I plan on running another small batch today and I will. The solution was a real dark green. It dissolved a lot of the coating on the board. I am also going to start out with full strength HCL and only add a small amount of Peroxide. I sure don't want to dissolve any more of my gold.

Art

Art


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## lazersteve (Apr 21, 2008)

Art,

Follow the Guided Tour link in my signature for some definitions and other info.

Process the various types of scrap separately. Mixing types of materials just complicate the process. Test small batches to determine which type work well with Acid Peroxide (AP).

Sodium Meta Bisulfite (SMB) is a common precipitant for gold.

Steve


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## Art Corbit (Apr 21, 2008)

Thanks Steve,

I thought that is what they were but I wanted to double check to be sure. Also I didn't remember if the Sodium Meta Biosulfite was sul-Fite or sul-Fate. If I remember correctly there is both. I have been trimming the gold off the boards pretty close to keep all the green crap out I can. I don't try to do the pins and the board gold together. I have been using only small amounts just testing but it seems either it doesn't work at all or it dissolves the gold first. The Gold is long gone and the copper is still there undissolved. I have never run into that before. Looks like my next step is to see if I can find some sodium Nitrate and mix me up some poor boys Nitric and try it. I'll be hanged if I'll drive 300 miles round trip to get the real Nitric. That would eat up a bunch of the profit.

Art


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## 67eod (Jul 30, 2008)

What product name do they sell the H2O2 and HCI under.

Thanks Bob



geekzilla said:


> After watching Steves video on the AP process with gold fingers, I too began to wonder if a more concentrated HP solution would yield quicker results. Thanks for trying it out and posting your results.
> 
> Incidentally, I have found an online supplier for H202 that has flat rate shipping to anywhere in the US for $9.95 (they also sell HCl)! Here is the link:
> 
> http://www.pondepot.com/index.asp?PageAction=VIEWPROD&ProdID=3161


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## Oz (Jul 30, 2008)

Hydrogen peroxide = H2O2
Muriatic acid = HCl


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## goldsilverpro (Jul 30, 2008)

You can buy 3% hydrogen peroxide at any grocery store or pharmacy or Walmart and HCl (muriatic acid) at about any hardware store. They are about the easiest needed chemicals to find.


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## Oz (Jul 30, 2008)

Thanks GSP, that was slack of me not to mention suppliers.


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## Palladium (Oct 11, 2009)

:arrow: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=2260&hilit=CUPRIC+CHLORIDE+salts#p19577


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