green AuCl

Geo · Aug 2, 2011

ive been collecting all the small leavings of the different processes and putting them in one container.i call it trash but it contains gold,it also contains plastic,solder mask,fibers from boards,base metals, and some blood sweat and tears :lol: i processed 25g of this material in hcl+cl, i used 1 cup hcl and a half cup of clorox in all,and still couldn't get all the gold foils to dissolve.too instead of the yellow or even yellow-ish color the solution came out a flat dull green color.was there so much copper there the chlorine was used up on the copper before it could attack the gold? should i have any problem precipitating the gold out? is there something i should do before i precipitate.hind sight is 20/20,looking back i realize i should have incinerated the material and then removed the copper first :roll: .can someone give me a clue?

eeTHr · Aug 2, 2011

Geo---

Complete the dissolving of the gold. That separates it from the junk.

Then pour the gold solution through a filter into another container.

This leaves all the junk in the filter. Wash any gold solution stuck to the junk through the filter and into the gold solution container with some water. A spray bottle works good for this.

Process your gold solution in your usual way.

(To get all the gold to dissolve, it would need a little more of either HCl or Cl, or both. Add a little HCl, and see if the gold reacts, if not, add a little Cl. If it has been sitting awhile, it probably needs Cl. But the HCl could be expended, too. I would standardly try HCl first, just to avoid too much chlorine when you go to percipitate.)

Geo · Aug 2, 2011

ok.when the reaction stopped short i just dumped the whole thing in a jar with a lid and waited to find out what happened,i now have about 16 fluid OZ of green solution with trash in it.so i just put it back in the dish then add hcl and watch for a reaction, if no reaction add clorox.so the deep green color is not a problem? i know this is not the way to do this but i had a very small 14k gold chain 4.6g and tried it in hcl+cl,it dissolved very well with a light green lime color.

goldsilverpro · Aug 2, 2011

Why do you think the gold will dissolve before the copper?

eeTHr · Aug 2, 2011

Geo---

Like GSP inferred, you must dissolve all the metals. You mentioned a dull green color, but if it is so dark that you can't see through it, your acid is probably saturated with base metals.

Depending on how complicated you want to make this recovery, there are other ways you could go with it.

On one hand, dissolving lots of base metals with PMs is not a good idea. But on the other hand, I suspect that recovering your PMs the simplist way for this one batch, might be easier on you, at this stage.

The simplist way I can think of is to dissolve everything, filter the solution into another container, and then cement out the PMs with thick copper suspended in the solution. I'm now saying copper, because you indicated there were lots of base metals in the solution already, and it sounds like there will be more (that depends on how much of the base metals remain undissolved).

Then refine the settled powders in your usual way.

And from now on get rid of the base metals first. But you probably already know that, and I understand that this is your "scrap jar," or stock pot.

Harold has a post somewhere, on his method of doing a stock pot, and I recommend that you read it when you can. But I'm not sure, at this stage of your experience, whether you would prefer to use his method, which is a longer process, or just grab your values out of what you've got, and then let out a deep breath, if you know what I mean.

The proceedure I suggested is not the "ultimate" solution for a situation like this, but in the beginning, sometimes a person just wants to complete a process and "see the gold." And I think that is understandable.

Geo · Aug 2, 2011

thanks for the tips.when i went back to my dish with my solution enough had dissolved that i could see 8 or 9 copper pins in the bottom and removed these with tweezers.after inspecting closely i couldnt see any more copper,im sure there is some i cant see,but getting those large peices out has to help some.the reason i thought the acid would attack the copper and not the gold is that i imagined the acid being used up before it could react to the gold because the ratio of copper to gold must have been greater on the copper side,if this makes any sense.i know incineration removes nitric acid,what is the process to remove hcl from material?