Gold from waste?

[CASACEO]

Okay, I am posting this to make sure I understand the next step to take for reclaiming gold from my waste solution.
Here are the details...
1. I keep copper 775 cpu backs in my waste solution jar and some black cemented onto them. (The black is Gold?) I removed the 775s.
2. I precipitated my waste solution with hcl and zinc powder. The result was brown mud. I 'washed' it in hot hcl till the solution was clear, siphoned off the fluids and dried it in a filter.
3. The filter has a tinge of green around the edges. (this is because of copper?)
4. Stannous Cloride test of powder is positive for precious metals. (tested with fresh SC)
5. Solution tested negative for PMs and was clear. No sediment was present.
6. It is my belief that this powder is mostly copper, gold and insignificant traces of other.
So...
I should incinerate then treat with nitric to remove base metals?
or
Treat with a dilute AP solution to remove base metals?
or
Something else entirely?

 

[Geo]

i think its all copper. perhaps contaminated with "whatever". you are no farther along with this lot than you were when they were whole. you may have went backwards a bit because it will be very hard to separate the gold from that.

 

[CASACEO]

I decided something else altogether...
As far as going backwards is concerned, I don't think I did. I went from 67 fl oz of waste solution to a filter full of gold bearing material. I took a small portion and made a button just to see. It was better then some that I've made before but very copper in color. (didn't take a picture)
Hoke says to refine it again with a familiar method and that's what I did. I just wasn't sure if AP or some other way would be appropriate. I tested two samples, one in a dilute AP and one in dilute nitric after incinerating. I combined the two samples after an hour seeing that the treatments were not effective... I didn't incinerate the rest and used Poor man's AR, it went well. Precipitating with Bonide SMB and should have results tomorrow.

This time I'll be sure to extract all my gold before treating my waste like a recycling bin.

Thanks for your input Geo.

 

[tek4g63]

You said that you tested your "filter sludge" with stannous chloride and it tested positive for gold. I was under the impression that stannous could only test for good in solution. If you used zinc to drop out all metals then your gold, if any, would be in metal form too, so stannous would not work to test for it. So from what I have learned so far, if you got a positive color when you tested your solids I would guess it was a false positive. Please correct me if I am wrong. Because I thought the reason for the color change when testing with stannous chloride was due to the tin participating the gold out as collides.

 

[Harold_V]

If you used zinc to drop out all metals then your gold, if any, would be in metal form too, so stannous would not work to test for it.

Excellent observation. Regardless of the fact that enough zinc may not have been used, there's little to no chance that any gold might remain behind, as once copper is precipitated, it, too, readily precipitates any gold that is remaining. So then, as you suggested, testing the recovered metal (with stannous chloride) is meaningless.

Harold

 

[CASACEO]

I do see the sense in what you say Harold, about it being meaningless to test since all the metal powders precipitated.

tek4g63: I did not know that SC was specific for liquid particles and it seemed to work on solid powders. I thought the tin and hcl turned black with the presence of gold particles so state seemed irrelevant.

Geo: You were right! It has been very difficult separating the gold from the copper. The smb dragged down an enormous amount of copper with the gold and has made separating difficult. I haven't finished processing it all but the majority so far has resulted in red gold.

 

[jimdoc]

I do see the sense in what you say Harold, about it being meaningless to test since all the metal powders precipitated.

Stannous is used to test for precious metals in solution. It is not for testing solids. Once you used zinc to cement, the gold should no longer be in solution. Then your stannous test of the solution should be negative.



Jim

 

[CASACEO]

Jimdoc,

I did understand what harold said, when he said it. It made sense. Thanks for repeating though...

 

[jimdoc]

Jimdoc,

I did understand what harold said, when he said it. It made sense. Thanks for repeating though...

Sorry, I thought you said "I don't see", I see now that you said "I do see".

Jim

 

[CASACEO]

Hahaha....

It's all good. My results with this batch have been less then desirable. I re refined most of my materials again and ran out of acetylene and HydroCLoric acid. Got to the precipitation of this material (with bonide SMB) I used alot less this time. Less is more... I think. Tomorrow I will pick up acid and fuel.

On a side note, I have been incinerating my filters and alcohol wipes. I burned them up and ground them down to a find powder. I do not have a furnace. Every refiner I have contacted from the internet has not responded and it's been over a month. Hoke says that most small shops use it for inquartation or send it to a refiner. Is there anyone that would be interested in processing these materials for me?

I'm going to keep this post alive until I have a solid pure gold button.

 

[jimdoc]

I would say just keep saving up the filter material. If you don't have a button yet, then you probably don't have enough to process yet. Study up on how to deal with them as you save up enough to be worth processing. I still have not processed any of mine yet, no hurry.

Jim

 

[Harold_V]

The smb dragged down an enormous amount of copper with the gold and has made separating difficult.

I'm going to make a recommendation I almost never make, and for good reason.

If you have access to nitric acid, your best approach at this point is to process the recovered material with dilute nitric. You may not even have to incinerate, but I'd advise that you do. If you choose to go the nitric route, and you prefer to NOT incinerate, start with just a small amount of dilute nitric and stir the contents very well, so any traces of chlorides that may be present are exposed to the nitric. That way they'll be consumed, and if they happen to dissolve a trace of the values, the traces will then be cemented by the remaining base metal. In the end, you should consume all of the base metal and have finely divided gold left behind. In any case, be certain to test the solution before discarding.

Harold

 

[gold4mike]

To clarify one thing for you - you said that the SMB dragged down a lot of copper. The copper that you now have with your gold isn't due to drag down, it's due to cementing it down with zinc. The zinc dropped everything below it in the electromotive series.

 

[Harold_V]

To clarify one thing for you - you said that the SMB dragged down a lot of copper. The copper that you now have with your gold isn't due to drag down, it's due to cementing it down with zinc. The zinc dropped everything below it in the electromotive series.

Yep, and my reason for suggesting a dissolution with nitric. That's a lot of copper that needs to be removed. I can't really think of another way aside from a copper cell, but they can be very troublesome, and certainly not worth the effort for a small single batch.

Harold

 

[CASACEO]

gold4mike, I understand your confusion. There was no zinc to cement the values at the time I used SMB.
I cemented the values from my waste with zinc and bathed it in hot hcl (which readily dissolves zinc). That is what is shown in the filter above.
When I refined the materials again I dissolved all the powders with Poorman's AR. This is where the smb precipitated or dragged down the additional copper.
I have attached photos of my most recent results.

 

[gold4mike]

You're right, I did misunderstand you.

Sorry!!