# peculiar reaction on AP ?????



## donald236 (Jun 10, 2008)

well the title says it folks , ive run a batch of fingers in a AP . i used the regular standard h202 and hcl . and my AP at first turned nicely green just like always . this is after 24 hours not all the foils have come off . now its brown in color and here's what i don't get here's the peculiar part half of the acid is clear as water (that's the bottom half) the top half is dark brown . why did it do that :?: :shock: :shock:


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## Irons (Jun 10, 2008)

Stir it and it will be all the same color. 8)


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## banjags (Jun 11, 2008)

I had the exact same thing happen to the batch of fingers I just finished in AP. I ran just over 5lbs in 3 liters of HCL and 1 Liter or H2O2. The reaction was pretty fast. I started reaction on Sunday and filtered out the foils yesterday... 48 hours. In another thread I asked why it was such a dark brown almost black... Lasersteve replied to more h202 and if that did not work add water after testing a small amount. I did both and it is still coke brown. But my fingers are no longer in this batch. It still seems to be reacting just fine. The only time it would turn green was when I added H2O2 and that was just localized around where it was added and when I added water it took a green tinge for a few seconds.

As long as it is still reacting it should be alright.


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## donald236 (Jun 11, 2008)

thx banjags


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## Anonymous (Jun 11, 2008)

I have been running the same brown acid for the last week using a bubbler and have processed several loads of pins and boards. I just filter off the floating gold and add a little more h2o2. Keeps on working. When I need to add mo acid, I am using "used AP"


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## Rag and Bone (Jun 11, 2008)

Firewalker

You are soaking entire boards in AP?


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## Anonymous (Jun 12, 2008)

No, just pins and such that I harvested off the boards. What I ment about boards were cut up pieces of gold plated boards after I removed the green sealent.


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## lazersteve (Jun 12, 2008)

If the AP is working fine just brown in color, it's an indication of high concentrations of copper chloride (I and/or II likely II since it's stripping fine). 

If adding water produces a white/gray cloud in the solution it's saturated with mostly copper I chloride (bad= add acid/peroxide in the right ratios). 

If no white/gray cloud appears, it's saturated with copper II chloride (good= dilute with water if desired). 

Brown solution is a pretty good sign no gold is dissolved in the mix, but always test with stannous before cementing. If you want to get the green color to stay pour off half of the solution and cement the copper out with iron. Properly neutralize and dispose of the spent solution after the copper is removed.

For the other half of the solution bubble air through it for 24+hours and/or add acid/peroxide (in the proper ratio) to bring the solution up to volume again. You may get by with just adding water to dilute the AP. If adding water only lightens the color your copper II chloride levels are fine and you won't need any acid or peroxide. If you start seeing the white/gray cloudiness, acid/peroxide is required.


Studying the copper chloride document on my website will help you understand all this.


Steve


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## donald236 (Jun 12, 2008)

thanks steve


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## OMG (Jun 12, 2008)

I've found that if you want to take some of the copper out of your mix, you can precipitate most of it electrolytically.
Just stick the cathode(copper would be good) in the copper chloride solution, and float a small clay flowerpot with some hcl and water in it and put a carbon anode in it. Then hook it up to some dc power source and the copper will build up quite quickly on the cathode.
You'll lose the chlorine that was bound up in the copper, but if you want to get rid of some of the copper without putting other metals in to precipitate it. this is one way to do it.
I've been using it to get the copper out of my waste acids.
It works with my waste acids, but I might have other stuff in there than you guys do. Maybe someone can verify if it works for them.


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## Anonymous (Jun 15, 2008)

Thanks Steve, will re-study your information....Jack


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## Blacktoadd (Sep 10, 2008)

In a consentrated copper solution I checked ph and it was about .2 i gradually started raising it with sodium hydroxide. it gradually started to turn brown, then as I got near a i it was heavily floculent brown, before 2 the brown was like paste. filtering produced a nice green solution. taking the brown and re lowering the Ph it all returned to a green clear copper solution. Am I changeing the solution back and forth from a cu 1 and cu 2 or forming copper oxide pase. Havent tried to melt this brown yet.


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