Memory Fingers AP question

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hauger

Member
Joined
May 24, 2017
Messages
24
Hoping for some insight on moving forward with a batch of fingers I'm trying to process.

I have approx. 7 1/2 lbs of memory fingers sitting in AP right now, originally generated by 1 gal of 32% HCl and 1/2 Litre of H2O2. After a week of working it seemed to have stopped, so I added another 1/2 L of H2O2 (making the overall ratio approx. 4:1 HCl to H2O2), and an aquarium bubbler. After another 7 days it seemed to have taken on a deep brown colour and didn't seem to be making any further changes, so reading up it sounded like the solution was saturated.

I added an additional 500 ml of HCl to introduce more free Cl to attach to the remaining copper.

3 days later, approx. 50% of the fingers are still attached. I pulled a few out to test and they aren't remotely loose. The colour of the solution remains a really dark brown (or possible green), borderline black.

I don't want to keep adding volume to the solution unless I need to....so the question is, do I need to? Is the solution saturated with copper, and if so, do I just keep running the bubbler and adding HCl?

Thanks for any advice.
 
Keep running the bubbler, CuCl is very dark and as long as you have a lot of copper left there isn't going to be a lot of CuCl2.It is consumed at the same rate as it is made by the bubbler.

If you get a white precipitate then the CuCl is saturated. At that time, stop the bubbler and let the gold foils settle, then pour off some of the saturated liquid and add more HCl. Then turn on the bubbler again.

Göran
 
Leaching Copper with C2C is a slow process that is very dependent on the solution temperature. You want to really stop adding H2O2, you only needed a 'splash' at the start to get it going. You do need a lot of HCl and you do need constant air bubbling. If your ambient temperature is a bit low, put an aquarium heater in there, speeds it up greatly.
 
Thanks for the replies. Probably a great point about the temperature, I'm doing this outdoors in early Canadian spring, so probably not the warmest.

I've still got the bubbler running, and truth is I'm not in a rush, just wanted to ensure things were still moving forward and not stalled.
 
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