HCL+H2O2 Finger Removal

---background---
I'm the new guy to the fourm. This is my first time attempting to refine. I used to do computer repair full time, now it's only a side job. I have aquired a lot of electronic scrap over the years. I could never part with - because there's gold in them boards!

I've seen many other methods online, but they always seemed to lack an important step. The closest thing I could find to 'real' was the subzero method but I didn't like the "here's how to do it...mostly...but hey - you gotta buy our mistery powder"

This is the best site I have come across! I apprecate all you have put forth for us!

---process---
I'm using lazersteve's method for finger removal. I didn't want to get too in over my head with chemical ammounts and fumes, so I chose the same setup but scaled it down to large plastic cups. I used 1 cup of HCL and 1/2 cup H2O2 plus a bit more H2O2.

The gold fingers started to bubble and things started to fume (I assume this is Cl gas). I agitated the mix and let it sit outside on the porch for a bit. This seems to be an exothermic reaction - things were getting warmer...not really hot...but warm. Not wanting the neighbors to have to smell anything I came up with the quick solution (not the liquid type) of using a larger container with a large vent on top. Covering this vent I placed a filter made of mesh and activated charcoal. I placed the reaction in the larger container and closed the lid. I understand that Cl gas is heavier than air, and most likely stays inside the container anyways but wanted an extra layer of protection. It seemed to stop the smell.

---Real question---
24hrs later I have about 50% finger removal. Things also stoped bubbling and fuming. They still smell a bit but no visable fumes. I also understand that this process can take up to a week if agitation is not used (I haven't done much since the inital agitation.) No problems there..that's fine with me that it will take a bit more time.

Are there any other gases I need to be concerend about other than the Cl gas from the HCl? Being that it seems now like it is 'stuff sitting in a greenish liquid' is it still reacting, or should I do something to the reaction? Tonight we are supposed to get frost. The reaction seems to no longer be exothermic. How tempature sensitive is this reaction? If I leave it ouside will it resume again once it warms up? Am I best to bring it somehwere more tempature controlled?

On a side note - I know in the video the stuff left over was placed into a bucket for something. What was that for? What do I need to do to render the leftovers safe once I'm done. Can I use them again for another reaction?

Sorry for the lenghty post. I want to be able to do this without killing myself, the neighbors, or my future grandkids.

Dr_Code,
from reading your post, I feel you are missing some of the finer details of the process, and actually missing the first leaching process (or just combining the leach of base metals with the dissolving of gold into one formula, which is not really a good idea).

To remove the gold foils we use a solution of HCl and 3% H2O2, this forms copper II chloride in solution (AKA acid peroxide solution), this dissolves the copper out from under the gold foils, the solution is not strong enough to dissolve gold, the foils are separated and rinsed.And now on to the second process to dissolve the gold foils, they can be dissolved in HCL/NaClO (bleach), or they can be dissolved in HCl/30% H2O2.

It sounds to me like you used concentrated H2O2, which would generate heat in the reaction,also generate chlorine and HCL fumes, it would also dissolve the gold with the base metals, depending on conditions the gold could cement out if copper metal remained or precipitate as very fine powder, (but can also be in solution with the copper), once the oxidizer was consumed the reaction would subside, and temperature does play a major factor as you said you smelled chlorine generated from solution (which is the oxidizer of gold), this chlorine is a gas, cold solutions can hold much chlorine, a hot solution forces chlorine out of solution as a gas, so heat can make any chlorine left in solution more reactive, and gas off dissolving gold on its way out to becoming fumes, (I do not think yours will boil over when it warms up tomorrow, but you could have a little chlorine fume off), if you did dissolve gold in this solution you can recover it by adding more material, the solution will dissolve the copper from under the foils and precipitate out any gold as fine powder, the solution would then become the copper II chloride solution.

The copper chloride solution can be regenerated and reused, until it is contaminated, re-read the copper II chloride document on Laser Steves web site.


Go back and do some more reading, to catch the finer details.

I will do some more reading. That's why I am here for.

The HCL I used was Muriatic Acid 31.45% (it was maybe 2 years old) and fumed when I opend the bottle. The H2O2 I used was Hydrogen Proxide 3% from the drug store (purchaced new for this attempt).

I will be more carefull, in the future, to not just use chemical names but to also include the percentage.

Thank you for the help about the cold weather.

I should also add things, for the most part, look like the video. I have gold foil foating arround, and most is at the bottom of the glass. There are some empty PC boards, and some that need a bit more time.

If you used 3% H2O2, you should not have generated much chlorine, and basically would not dissolve any gold as long as you disd not use it in excess.

so it sounds like you are on the right track, I was answering to what it sounded like to me, in your description above when you said you smelled chlorine gas and a very reactive solution, it made me think you were generating chlorine gas and dissolving gold into solution, which now seems like is not the case, so maybe you just smelled the hydrochloric gas from the solution in those vapors, thinking it was chlorine gas.

but do not let this deter you from reading more, just because I am wrong in this case. :lol:

The starter use 1 cup of HCL and 1/2 cup 3% H2O2 for fingers
I want to use 35% H2O2 because here there isn't 3% in drugstores
So If I use 1 liter of HCL , how much 35% H2O2 I must use?

Thank you

saadat68 said:

The starter use 1 cup of HCL and 1/2 cup 3% H2O2 for fingers
I want to use 35% H2O2 because here there isn't 3% in drugstores
So If I use 1 liter of HCL , how much 35% H2O2 I must use?

Click to expand...

About 1 ml. Seriously! The old idea of using a cup of HCl to 1/2 cup of 3% H₂O₂ is wrong. Adding that much peroxide at the beginning will dissolve some of the gold. You can recover it at the end because it will cement out as a fine black powder that will precipitate when the solution becomes saturated, but that's not the best practice. One of the advantages of the copper chloride (AP) leach is that the gold foils are visible the whole time. It makes it an ideal first process for beginners.

I started my first copper chloride leach with 200 ml. HCl and about a half a capful of 3% H₂O₂. I put some copper wire into the solution and let it dissolve to use up the H₂O₂. Then I added my fingers.

Dave

FrugalRefiner said:

saadat68 said:

The starter use 1 cup of HCL and 1/2 cup 3% H2O2 for fingers
I want to use 35% H2O2 because here there isn't 3% in drugstores
So If I use 1 liter of HCL , how much 35% H2O2 I must use?

Click to expand...

About 1 ml. Seriously! The old idea of using a cup of HCl to 1/2 cup of 3% H₂O₂ is wrong. Adding that much peroxide at the beginning will dissolve some of the gold. You can recover it at the end because it will cement out as a fine black powder that will precipitate when the solution becomes saturated, but that's not the best practice. One of the advantages of the copper chloride (AP) leach is that the gold foils are visible the whole time. It makes it an ideal first process for beginners.

I started my first copper chloride leach with 200 ml. HCl and about a half a capful of 3% H₂O₂. I put some copper wire into the solution and let it dissolve to use up the H₂O₂. Then I added my fingers.

Dave

Click to expand...

Thanks Dave
It is easier to dilute my H2O2 with 11 part of water. So I must add 12 ml 3% H2O2 for one liter HCl
But palladium says in another topic:

The correct ratio of hcl to H2O2 is 2 parts Hcl to 1 part H2O2. If you use 1/2 liter of Hcl then you need to add 1/4 liter H2O2. Then use air on top of that. Solder is a pain in the butt. Try soaking them in straight hcl with no air to remove the solder first

Click to expand...

It is for pins not fingers.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=11057
Do you say this is old idea and it's wrong ?
I am confuse because there is a big difference. (12 ml vs 500 ml)

Yes, it's an old idea from 2011 and we know better now.

You don't need to dilute the H₂O₂. It doesn't need to be exact. Just use a small amount. It's really not necessary at all. You can use just HCl and an air bubbler. The peroxide just gets the reaction started more quickly.

Dave

FrugalRefiner said:

Yes, it's an old idea from 2011 and we know better now.

You don't need to dilute the H₂O₂. It doesn't need to be exact. Just use a small amount. It's really not necessary at all. You can use just HCl and an air bubbler. The peroxide just gets the reaction started more quickly.

Dave

Click to expand...

Hello sir,

Hope you're doing well, I had a question after reading most of these cupric chloride posts. I was earlier suggested to do the same as you have mentioned, but I have a question regarding a different approach with the same solution. CuCl2 is basically an etchant for copper and removes the nickel as well from under the foils after detaching them from the fingers is what I have learnt so far.

If we manually remove these foils from the fingers using a solder iron and then add them to the cupric solution, do you think it would work the same way of eliminating the copper and leaving behind just the foils to be recovered later? By this time I assume the gold foils alone may have some purity since the nickel and copper would have been removed.

If it is possible, how much time do you think we could assume that the solution has done its job for the same so that we can move onto the next step of refining?

Thanks

Yes, it will work, but why waste the time removing the fingers manually when the leach will do it for you?

As far as the time it will take, it will take what it takes. It depends on temperature, solution concentration, circulation, etc. Don't over complicate it. They'll be done when their done. Use the time to find more scrap or work on other things.

Dave

Very well noted with thanks.

Another concern, if the vessel holding the solution is exposed to sunlight, would it make a difference? I know it sounds like a basic chemistry question, but has been hard to find anything oriented to such concerns to clear it up.

jibrannajam92 said:

Very well noted with thanks.

Another concern, if the vessel holding the solution is exposed to sunlight, would it make a difference? I know it sounds like a basic chemistry question, but has been hard to find anything oriented to such concerns to clear it up.

Click to expand...

Heat is good, but besides that the only concern may be Silver which will not be present in Foils.

How come some of you manage to make the simplest tasks so difficult?
Do some testing and observe.
As long as there is no Cyanide, Cadmium, Arsenic or Mercury involved you can do small samples and observe.
Which means all normal scrap is safe.
At least all fingers are safe.

Yggdrasil said:

simplest tasks so difficult?
Do some testing and observe.

Click to expand...

I just didn't want to run into an over reaction or a HCl decomposition if it could be possible with the presence of sunlight. It wasn't even my question but you added to my knowledge! Many thanks for that!

Hydrochloric is a gas dissolved in water. Mild heat will help but too much will cause the gas to be expelled from the water. 100F to 125F should be OK. I keep mine sitting outside in the sunshine for months at a time. The reaction isn’t violent like some other acids but always allow some head room just in case. I try to keep between 1/3 and 1/4 of the available space free.

Shark said:

I keep mine sitting outside in the sunshine for months at a time

Click to expand...

This must drfinitely be generating some fumes? Im actually inquisitve because of the surroundings i have to take care of. Plants, animals, humans etc. I generally do my chemical pratices late at night to avaoid a major hassle. But this process requires us to leave the solution as it is. So it still remains a concern. I read somewhere here about the technique of placing the vessel containing the solution in another larger vessel to control the issue of fumes. How does that work?

Yggdrasil said:

Heat is good, but besides that the only concern may be Silver which will not be present in Foils.

How come some of you manage to make the simplest tasks so difficult?
Do some testing and observe.
As long as there is no Cyanide, Cadmium, Arsenic or Mercury involved you can do small samples and observe.
Which means all normal scrap is safe.
At least all fingers are safe.

Click to expand...

Doesn't H2O2 decompose in sunlight?

It definitely has some fumes and care should be taken around plants and animals, including humans. I used 250 gallon totes, and set buckets in them, similar to a fume hood.

And yes, H2O2 will decompose with sunlight, but it is only used to kickstart the CuCl2, not to keep it running, the air pump will work better as it seldom adds enough oxygen to dissolve gold. Even better than peroxide, use copper oxide in place of peroxide. This way there is less chance of dissolving the gold.

And always remember HCL fumes will rust metals that are exposed to it.

Shark said:

I used 250 gallon totes

Click to expand...

This must definitely need some space lol.

And would definitely attract tonnes of questions from everyone that visits my residence. I may need to work around a solution suitable in my case.

I did a little research and came across this : SCRUBBER

Is there any possibility that we could DIY this thing. I simply love how its a win win against these chemical fumes escaping and further damaging the atmosphere. I need to learn all about it. I'm reading along this on Wikipedia. Is that a reliable place for info? I mean anyone could just change and manipulate what's there.