Unable to dissolve gold via HCL/Clorox method

[luckypyrate]

OK, so I have watched Steve's video a hundred times, backwards and forwards, and for some reason I cannot get these dang flakes to dissolve! I re ran the processor pin dissolve process on the whole batch thinking maybe it was an over abundance of undissolved pins that was causing the HCL/Clorox process to not work, but upon rerunning it I got the same result. It seems like some gold is dissolving as there is a gold/green color in the liquid, and I am keeping the filtered out liquid to drop with SMB pending stannous test. I guess my question is what is going on that is keeping my HCL/Clorox from running as quickly/thoroughly as Steve's video portrays?

EDIT....sorry I guess I need better ventilation...fumes must be getting to me. I edited AP to HCL/Clorox as that is what I meant.

 

[Palladium]

You don't dissolve gold with ap, you dissolve copper. Gold is dissolved with acid/clorox.

 

[eeTHr]

lucky---

I think what I'm reading is that you first used HCl/peroxide to dissolve the base metals out of some pins. Then used HCl/Clorox to dissolve the gold which remained, but the gold is not dissolving completely.

If your pins were heavily plated, on their entire surface, it could be that base metals were not dissolved, because there was no access to them through the gold. Then the Clorox dissolved enough of the gold on some of the pins, to start on the base metals inside. But some cementing of dissolved gold, back onto the base metals occurred.

If this is the case, you would probably need to bite the bullet, and just do a total dissolve, using more Clorox, until everything is in solution. This is where the sulfuric cell comes in handy!

Another possibility is that the base metals were accessable to the HCL/peroxide, but only a portion of them dissolved, leaving a significant amount of base metals solid. If so, the original HCl/peroxide process was stopped to soon.

What kind of pins did you process in this case?

Was the A/P still reacting? There are ways of restarting the reaction, as Steve explains. Was it producing color in the solution?

Also, proper washing will reveal base metal color, before starting the gold dissolve. You can wash foils, similarly to washing precipitated gold, for a cleaner dissolved solution, and thus a cleaner precipitation. Check the two links below---

Washing the gold powder after using SMB

It has everything to do with how you're refining.

Hope this helps!

 

[luckypyrate]

Here is the general breakdown of what I have done so far:

I had seperated the pins from the processors using the heated HCL method, which works quickly and efficiently enough, although I have to separate the small chips from the pins in this method (not difficult just another step). I then dumped the pins in with the batch of RAM fingers, PCI fingers, and SIM cards (and other various nick-nacks of similar nature) for AP. Once the AP was done (about 72 hours with heavy aggravation throughout) I went forward with the HCL/Clorox method. It would not work, turning green and eventually brown after about 5-10 minutes. This time, nothing seemed to go. So I left it to the side for some time after washing the batch down with tap water until I could get back to it. When I got back to it it was crusted with rust in places so I washed it down with HCL and that cleared it right up. I then tried the processor pin process of boiling the batch in HCL for 3 hours. The first time I did it, there didn't seem to be much result so I did it again and for the whole night. This morning much of the HCL had boiled off and it seemed to have dissolved most of the pins. Encouraged, I moved forward with the process. This time, there was some gold hue in the green but eventually it went dark green/brown, didn't dissolve all of the flakes and we are back to the drawing board. Grrr!

 

[eeTHr]

Grrr!

8)



The dark color says "base metals." One way or another they were still in there.

It sounds like you have more base metals than just a wash, even prolonged, in boiling HCl is intended to remove.

Lots of base metals can exhaust your dissolving solution, including A/P, HCl/Clorox, and A/R. Did you do what Steve describes in order to rejuvinate the A/P solution, before pouring it off?

There are actually many kinds of "pins." From processor pins, to card slot pins, on up to cable connector pins which are usually plated all over (and the plating can be heavy on these, especially military specification ones).

Did you have anything in there that could have heavy plating all over the surface?

It sounds like either it needs to go longer in rejuvinated A/P, or you have things that are plated heavy all over, and the HCl/Clorox is getting through the gold, to the base metals, but becoming exhausted before a complete dissolve, and so you are getting some cememtation back onto the base metals.

 

[Claudie]

If you just removed the CPU pins with heated HCL, the base metals were still there. If you continue to heat the pins until they float, the hot HCL will dissolve the base metals leaving you with cleaner Gold foils. There is a video demonstrating this process at http://goldnscrap.com/index.php?option=com_content&view=article&id=78:scrap-gold-recovery-from-fiber-cpu&catid=36:scrap-cpu-a-chips&Itemid=2

 

[luckypyrate]

That is the pin dissolving process I use, claudie. I found that specific site while going through this debacle... In fact it was that site I referenced some post above. I will try it again though...is it possible that not corking it or preventing evaporation enough may be preventing sufficient reaction?

 

[eeTHr]

lucky---

I think your problem with that is most likely a severe lack of Hoke.

You should use the search feature at the top right of this page, and thoroughly study this phenomenon. Coincidently, it can seriously affect several aspects of your refining. So you would do well to get a good grasp on it now, rather than causing yourself lots of headaches in the future.

 

[lazersteve]

Sounds to me like you mixed various scrap types which is a big mistake made by beginners. Secondly the 'pins' sound like kovar pins from new green fiber cpus which are hard to dissolve and of very low yields. You will be waiting a long time for hot HCl to dissolve kovar. If you succeed at dissolving the kovar you won't have foils, but tiny flakes instead.

I would recommend saving the current batch until you can process a 600 g batch of normal card fingers of the same type and repeatedly produce 2-3 grams of gold. Chasing traces of flash plating off of a few modern cpu pins is nothing short of a waste of time as a learning experience. Once you can pick a piece of 'low hanging fruit', reach for some of the more difficult fruit. Unless you have nothing better to refine, or hundreds of pounds of newer green fiber cpus with kovar legs, put them on the back burner until you become more adept at refining the easy stuff like fingers.

In short, pick your battles and pick the ones that are easy to win at first.

Kovar is best digested with sulfuric acid or aqua reqia.

Steve

 

[auction_junkie89]

Kovar is best digested with sulfuric acid or aqua reqia.

Steve

Hello everyone!

I'm working on a project identical to this one, and I have several pounds of these CPU pins handy to process, gathered gradually over time here and there and melted off with a torch, been saving them up like change in a quart mason jar, that is almost full at this point. I have quite a bit more than just the pins, but I decided to run a batch for each different type, separating CPU pins, Misc. Circuit board pins, I have a large quantity of material here in short...

I got a bit anxious to turn my paperweight something a bit shinier and easier to fiddle around with. (First mistake)
I've been attempting to do it all in 50/50 32% HCl & H20, when I researched/realized that your methods speak of the C2C method for copper-based material, aka circuit boards and similar devices.
Right now, under the "Tutorial Questions/Comments" forum, I have my current stage of product, and it hasn't been touched since I've filtered the pins and sand out of the original solution.
From here I'm thinking to remove the material from the foil, and dry them well (Noticed that SA doesn't agree with water well.)
--and then giving them a bath in SA

I know that I'll be performing more research, instead of just taking the direct approach as most of the newer folks (and myself) do from time to time.

My question is: So, when you say that Kovar is best dissolved in sulfuric acid, I can get a lot of that stuff for cheap, and if I could get any information as to how many grams of pins to how many ml of SA would I need to use?

Thank you so much for all that you do!

~Drew