gold foils gone!

[solarsmith]

made about a pint of AP and put in about 10 strips of gold card edge fingers. saw lots of fingers floating and after I added the 3rd batch of peroxide they all disolved... I was not expecting this.. :?:
I am not dumping anything I know the gold is still there. I was just amazed that gold could be disolved with only muratic and peroxide..
ok so next thing I do is get my long stainless steal forcepts out and remove the plastic chips one at a time. and the I noticed the forcepts are getting coated with a brown sludge powder. what is it???
I then added more peroxide to the beaker and disolved the brown powder back into the AP mix...

any help most gratefull thanks BRYAN

 

[skyline27]

First of all, don't use metal tools in AP or any other reactions. You will damage your tools and contaminate your solution. It sounds like you used too much hydrogen peroxide. The idea is to use just enough to loosen the foils. I had the same problem when I was starting. Be patient. The gold is not lost. You can precipitate the gold using SMB.

 

[Harold_V]

I noticed the forcepts are getting coated with a brown sludge powder. what is it???

It's your gold, being precipitated by the base metals contained in the forceps. That's the basis of a stock pot, where you place solutions that contain traces of values, but not enough to pursue directly.

As has already been wisely advised, keep all metallic objects away from solutions of precious metals, and don't discard anything that comes down when they contact one another should you screw up and mix the two. It's assured the resulting precipitate will be valuable, although copper will also precipitate on steel, aluminum or zinc.

I then added more peroxide to the beaker and disolved the brown powder back into the AP mix...

any help most gratefull thanks BRYAN

So it was dissolved once again. No harm done. All you have to do is filter the solution and precipitate the gold. The one bad thing is that your gold will come from a very dirty solution (contaminated with unwanted base metals) so the gold will be of questionable quality. Now you know! Avoid dissolving base metals with your values if your goal is high quality precious metals.

Steve is the man for this one-----I always used acids and evaporated. I'm not even remotely familiar with the process you used, although I certainly recommend it.

Harold

 

[Smitty]

Test using stannous chloride to see if any gold is left in solution. If it test positive for gold then precipitate using SMB and filter out the brown and black powder. That should have be your gold and base metals. Then I suggest you do the wash that Harold has outline in one of the threads using muriatic acid and water. I accidentally dissolved my gold using AP once, but it was foils only and no base metals in it.

good luck

 

[synthetiklone]

Heh, horaay!
I found someone else that has done what I've did. I don't feel so daft now

I've lost a fair bit of gold now though. I was initailly using hydrochloric to dissolve pins and plated cpu lids, but it was taking weeks, and alot of acid.
So I studied the AP process, room temp, dissolves base, not gold. yay.
After removing the fine gold and bits from straight hydrochloric, I was ready for a AP trial cleanup/dissolve the copper/nickel and wondering why the solutions were turning yellow, so tested with stannous chloride, and got clear result, ok to dump solution! The cpu lids have etched alittle around the edges, and the pins are almost digested.
I syphoned off some smaller gold particles from the pins, and put in a new batch of AP.. one day later all the nickel/copper bits are almost gone in the gold dust. Two days later, all the gold is almost gone! yikes, the solution is yellow, so I test with stannous again, and again clear!?!
So I think my stannous chloride powder is faulty, so I mix up some tin and hydrochloric, heat/dissolve and test again, again - clear. Got me stumped. I know the Au dust is definately in this solution, as it was also in the other solutions, so I guess I'll try stuffing up a SMB precipitation .. (It may work, fingers crossed) No harm done now, I've already lost the bulk of my efforts. But I'm still learning.
By the time I perfect the process, I will have no raw scrap left, and my wife thinks I would have been better off using the few hundred dollars spent so far buying her some gold jewellry! heh..

I now know (I think I'm sure) AP (2:1 (3%) ratio) will slowly dissolve base metals AND all your fine gold flakes at room temp if you leave it a day too long. I also know NOT how to make a stannous test work! I also wish I had just used nitric, as I've done before with great FAST results (but I didn't have any left, and will try and make some once I figure out how to get the solution to -5degC without using the kitchen freezer (no way).
I also know AP is terribly terribly slow for cpu lids, and I will be also building a reverse plating cell to try out. Problem there is, I've only got a few cpu's left, so it mightn't be worth the trouble.

Well, just thought I'd share my experience, so others may learn.. err.. laugh.. at my ventures.

Cheers
and regards

SK

SUCCESS - UPDATE: Thanks banjags..

I think my HCl solution may be weaker than I thought, as I stuck to the correct mix for the peroxide, which is based maybe on a stronger HCl than what I have, which only states 290 g/L on the bottle (grams per litre) (I'm presuming that means 29% HCl). Maybe a few % under strength for the recommended ratio.

Got stannous solutions (premix, and DIY tin-HCl) to test positive after a bit of practice, found it works great when warm. Love those little purple rings - might even frame my first testings for nostalgia! heh..

Yes.. I used SMB to precipitate, initially nothing happened, so I thought I may not have mixed up enough SMB, while I started mixing up a new saturated solution, I noticed my AP-gold-SMB solution starting to go muddy brown.. yay.. stirred up a bit more.. boy what a pong! invisable fumes smell like suped up SMB and hydrochloric.. funny that ehh!

Anyway, now a few days later, and success, brown gold dust is clumping together in bottom of beaker, and now has had H2O and HCl washes. Now if I can figure out how to download lazersteves melting demo, (it's simply too big a file for dialup) I could do with some hints. Last time I tried melting gold dust, The flame blew the lot clear off the table! haha

I'm feeling really quite proud despite things going awry most of the time, Thanks HEAPS again to steve, harold, irons, gsp, cat someone, and many others here for your posts, and advice, without which I (many ppl) would have given up long before.

SK

 

[banjags]

My first batch went as expected I put thing items in to be dissolved after a couple days there were lots of foils floating about the mix, filter and all was good. But then I decided to try 12% peroxide (if 3% took a couple days 12% should do it in 1/4 the time.)... poof the gold was gone very fast. lol. as well as the base metals... DOH. I did recover all my values but the point I am try to convey is patience is a virtue when dealing with AP. If you have plated items such as lids and pins etc and want faster results use a cell. They are alot easier to deal with and you always see your gold (black sludge).
My advice would be even though your stannous test is showing clear (old solution maybe?)... you know there is gold in solution either just hang on to the mix and use it later when you have more stuff to process or drop it with smb. smb is cheap and it will get your values out.

 

[skyline27]

I've been experimenting with 36% H2O2. So far I am very pleased with the speed and power that it strips fingers and cpus. You might consider using it for more persistent materials. I'm reusing acid that I inittialy thought was spent. Even after nearly a year it has plenty of life left.

 

[banjags]

I've been experimenting with 36% H2O2. So far I am very pleased with the speed and power that it strips fingers and cpus. You might consider using it for more persistent materials. I'm reusing acid that I inittialy thought was spent. Even after nearly a year it has plenty of life left.

Do you rejuventate with air or h202?

 

[skyline27]

I aerate during the reaction and add H2O2 as the reaction slows and the solution gets very dark. It makes quick work of the most persistent foils. The aeration also serves to agitate the material. My reaction bucket is sealed airtight and the exhaust is pumped into a column of water and baking soda to neutralize the fumes. The fumes were starting to corode all the nearby metal. I will never use 3% H2O2 again.

 

[banjags]

I am thinking of doing somthing like what you are doing with the vent. Could you post a pic of what you setup looks like?

 

[skyline27]

My setup is 200 miles away and I won't be back to it for a couple weeks so I can't post a pic. Here is a description:

I use a big home brew primary fermenter bucket with a sealed lid for a reaction bucket. The lid has an air intake and an exhaust. A 100 gallon aquarium pump forces air into the intake, down a tube into the bottom of the bucket for aeration. The exhaust tube goes into a 3.5' tall glass vase filled with water and baking soda.

This is my second generation AP rig (the 1st generation being the basic setup as seen in steves video). The third generation is in the works!

 

[banjags]

Are you using a silicon based caulking to seal around things? As I understand the only thing that would resist the fumes would be silicon.

 

[skyline27]

I used "Amazing Goop" plumbing sealent. It's holding up after several batches. The reaction bucket biulds up a lot of pressure before it releases through the exhaust so a good seal is needed.

 

[solarsmith]

ok my last post I said the foils had desolved into the AP solution.

I added a crushed cpu just to make it a real mess even a few racks of conector pins.. almost all of it went into solution... Yes I know its going to be a dirty mix... I do want to know how to handle a dirty mix because this summer I will be working on the gold mine and getting a real mix of pgms out of it as a concentrate. copper silver gold platinum iron uranium
pirites sufides and more. so learning how to process dirty stuff is a good thing for me... any ways... back to the mix... I filtered it and got a nice dark green solution... next I made a batch of smb and and added a healthy dose to the solution.. the next day the bottom of the jar had a half inch of white flake christals in it.... (I think it was from adding way to much smb) ok on to the next step... I filtered out the christals and started washing them with warm tap water the rinse water first pint came out BLUE? any one want to tell me what is making it blue? :?:
the next pint came through clear and the christals are mostly gone.
Now the good news.. the white christals have given way to a very nice looking red/brown pricipitate. just like in the pics I see on this forum.
any sugestions as to my next step are most welcome
:?:
thanks to all BRYAN

 

[Rag and Bone]

My suggestion is soak the powder in straight HCl to remove the base metals. In the future I would recommend using more material. Based on what you said you processed I would expect less than a gram. Maybe a 1/4 or 1/2 gram. Tiny amounts of gold are really hard to chase around.

 

[lazersteve]

Blue= Copper Chloride.

Steve

 

[Art Corbit]

I just flat don't understand what goes on with the AP. I tried it and only put a small amount of Peroxide in it and it dissolved the gold before I could spit. The copper was left bright clean copper. I finally started making my own Nitric Acid and using it to strip the electronic gold. So far it's the best way I have found to do it.

Art

 

[Rag and Bone]

Use a full batch of material. At least a pound of fingers or high yield cpus, preferably more. If you have a small amount of material it will put it all into soluion. it will dissolve some gold, but it all comes out in the wash.

 

[Art Corbit]

I knew I did something wrong but I had no idea what it was. I only used about a half ounce of pins. Thanks.

Art

 

[Rag and Bone]

It seems to be a common occurence.

For small test batches I use a petri dish and cover the material (usually pins) with AP using a syringe. Some pins strip well in AP, others don;t.