Where did my foils go ?

[limestonecowboy]

Today I decided to try some foils in AP

90 sdram fingers and 60 PCI card fingers.

Everything was good, colour and reaction etc.

Tonight I looked and they were all stripped ! Great.

I went through the clean-up and when I got to the bottom of the bucket there were no more than a hundred or so foils there ??

So, where did all the rest go ? did they disolve ? and how do I re-precipitate any gold from this stage ?

I must add that the HY Peroxide was 9% so maybe I added too much ?


At the half way stage there was lots of gold floating around in there.

 

[Rag and Bone]

Some of the foils probably dissolved and precipitated as fine, dark powder. Only use enough solution to free the foils. This will lessen the amount of dissolved gold. For a small batch like you described, a few cups would be enough.

Save the solution and re-use it. The dissolved gold will precipitate when you add more scrap material. The stronger H2O2 will dissolve more gold than weak stuff.

 

[limestonecowboy]

Cheers R&B

Ok so there was no fine powder in the bottom and the mixture was a clear but deep olive green showing a yellowish colour around the edges, so I guess the rest of the AU is in solution.

I have saved the concentrate for my next batch which I hope to get in tommorow so all is not lost.

Could I drop any gold out of this using SMB ? I guess it would render the solution 'spent' so I could not process anything else with it ? and I would have to dilute it or neutralise it before doing a drop ?

Forgive me, I am still wading through Hoke at the moment (when I get time) but I;m learing fast.

 

[Smitty]

First is to get some stannous solution to test and verify the gold is dissolved in the solution so when you do go and precipitate the gold, you can verify that you've recovered everything.

I learned from one of the veterans here to just add more material you want stripped. Don't ad anymore Peroxide. The reason is because the dissolved copper will eventually precipitate the gold in solution as a black powder like rag and bones had described.

If you plan on just cleaning up what you have and throw away the solution, then you can add smb and precipitate the gold and start your powder cleaning steps. I've done both methods.

good luck.

 

[limestonecowboy]

Thanks Smitty,

I added another small batch today, I didnt add anymore peroxide, although the reaction is now a little slower , but I expected this.

I have one more batch of 100 isa card fingers to add tommorow and that will be it for this mixure so I will drop it with SMB.

I have today made my first batch of stannous which has shown a purple streak, so there is gold in solution, and I can check that I have recovered it all when I am done.

Cheers for the advice,

what a great bunch we have on this forum,

Best wishes,
Richard

 

[limestonecowboy]

OK, so I have now done with my AP batch.

I have filtered all the solids out and tested the remaining solution with stannous which shows it does contain alot of dissolved gold.

How do I precip ?

Do I need to neutralise or dilute before doing a drop because it is still active?

If I need to dilute, what ratio ?

Cheers , Rich

 

[lazersteve]

Rich,

If you want to reuse the solution you should keep using it until the black gold powder is forced out by saturation with copper.

If you are not going to use it any longer bring the pH up to 4-5 with soda ash and add powdered zinc to drop the gold as an impure black sludge. This sludge will require purification to get the gold. Start by boiling it in HCl then rinsing with water. Then dissolve in AR or HCl-Cl and precipitate with SMB.

SMB won't drop the gold effectively if the solution is still active.

Steve

 

[limestonecowboy]

Steve,

Thanks so much for the prompt reply.

If I decide to re-use the solution I need to know...

Does the AP have a shelf life ? It could be as much as two weeks or more before I get enough scrap for another batch ?

Will it be safe in an airtight container ? I dont want acid exploding all over my workshop !

Will I need to re-activate it with some fresh HCL ?

Thanks again,

Rich

 

[lazersteve]

Rich,

AP keeps very nicely.

I keep mine in an open bucket. As long as the solution does not have any scrap in it you should be okay to put a lid on it.

If stored without a lid you will have some evaporation to contend with which can corrode nearby metals.

I've actually completely dehydrated AP down until it forms beautiful emerald green crystals and used these with only tap water to rapidly dissolve batches. A bubbler setup speeds the work of the crystals. When the solution darkens to a chocolate milk color, or looses it's kick, add a little HCl until it turns emerald green again. When using a bubbler, no peroxide will be required again. Peroxide is the active ingredient that will cause your gold to dissolve. By limiting it's use you can limit the amount of gold that goes into the solution.

Remember the working chemical behind the AP reaction is not the acid or the peroxide, it's the Copper II Chloride (CuCl2). It really should be called the CuCl2 method not the AP method.

Steve

 

[limestonecowboy]

Cheers again Steve, you really are 'The greatest'

I have not yet come across anything in Hoke relating to this method and I am at about a third of the way through the book.

So the advice on AP is really helpful.

I am also cutting and pasting information from the forum posts and compling them into pdf files to save me having to sift through pages and pages of forum several times.

Will keep you posted when I have my first button, which should not be long now.

BW

Rich

 

[Harold_V]

You won't find any of the work-arounds promoted on this forum in Hoke's book. She wrote with the idea that one could buy the needed chemicals. Sadly, that is no longer the case, so Steve and others are providing invaluable information that permits successful processing, circumventing the need for the unavailable acids.

Smart move, reading Hoke. Even if you don't follow the book in your processing, it will have expanded your knowledge such that you will have a far better understanding of refining, regardless of the method you choose.

Harold

 

[limestonecowboy]

Cheers Harold,

Yes, I am finding Hoke interesting and very useful in understanding chemical reactions and processes. Also good for processing the 'by products' silver etc, which I never even condsidered.

Great book and easy to get the head around, even though outdated in terms of pricing, and what chemicals are available to the general public.

Here in the UK there are not many at this game so good supply of scrap available, hopefully I can manage to knock up a few Oz.