AP Color Indication

[ddelozier]

Im new to Gold recovery, and i've done several small batches. I have not moved past seperating the gold foils from the computer components. Im saving up my foils/dust.

I am using a standard A/P Solution
HCL covering the the material to be stripped off, then H202 in small increments untill the solution goes
emerald green. Air bubbler via small aquarium pump providing added oxygen and liquid circulation.

For the most part, every batch has done the same, The solution gets progressively darker green until it is nearly opaque. But Recently i have had 2 batches go very sideways on me. The A/P Solution in 1 changed over an 8 hour period from a lovely emerald green to a clear brown stained almost TAN color. Another batch(5 going at once FYI), the A/P went from Emerald green to nearly Florescent BLUE. I was wandering if anyone could tell me what those colors mean, and if there is a color chart anywhere that lists what various colors in the A/P Solution might mean in the way of progress(Good, leave it alone), stalled(needs attention), and Failed(something went really wrong)

Thank you for your time.

Devin

 

[glorycloud]

I reuse my AP solution and have been for years now. When I don't use it
for a while, I just leave it in a five gallon plastic container with the lid
on loosely and it eventually gets back to the emerald green color again.

When I am using it on gold fingers, it is always a dark brown color. I will
from time to time add in some fresh HCL but I never add any H2O2 as it
is not needed anymore.

 

[Shark]

The clear/brownish color could indicate that something is cementing the copper out of solution. My first suspect would be iron, as in kovar pins, but there are other metals that could be suspect.

 

[ddelozier]

Ok, i added more Hcl to the solution that was brown, no reaction. I added more H2O2, and it went back to green. next day, its now turning Blue/green, getting more Blue by the day...not dark blue, but neon blue. Did i add something with the Motherboard Pins, IDE Pins, and ram slot pins, that would affect the color to make it blue? All the pins i added were clean of plastic/rubber, and the HCL and H202 were both fresh from the bottles new. I do have a bubbler going, and i can add H202 and it will go back to green for a while. What the heck? LOL

On a Positive Note, the Gold is being Efficiently stripped of the Pins quite well.

 

[everydayisalesson]

Hey dd, as glorycloud posted, you don't need to add anymore H2O2. If using an air bubbler, you don't need any. A lot of guys add a little in the beginning to just give it a kick start. I used a cap full, roughly a tea spoon, to a gallon of HCL for my first AP batch. I put in the air bubbler and have been recycling the same solution with small additions of HCL every once in a while for 2 years. Sounds like you may also be dissolving some of your gold, I would check it with stannous. Hope this helps.

Mike

 

[donald7755]

Sounds like you may also be dissolving some of your gold, I would check it with stannous. Hope this helps.

Mike

are you saying that the brownish color could mean that the gold is dissolving into the solution ?

 

[ddelozier]

The color is back to Emerald green now. Im wandering if i wasnt getting enough oxygen input from the bubbler. It was going slow. I added a bigger pump. However in a previous post it was suggested i might be desolving gold into my solution. To force that to precipitate out, should i just drop in a chunk of copper?

 

[g_axelsson]

The brown color is probably from a lot of CuCl in solution. With oxygen or H₂O₂ the CuCl is transformed into the green CuCl₂. CuCl₂ is then dissolving more copper again.

There is a copper chloride document on Lazersteve's website, http://goldrecovery.us/ that shows the colors of different concentrations.

It is when the solution is green and you have extra H₂O₂ that you risk dissolving gold.

Don't add extra copper unless you run out of metal in the leach and testing shows that you have gold in solution. Gold that was once dissolved but cemented back onto copper will not look like foils any longer, it will be a brown or black sludge.

Göran