Lovely gold AR with no SMB reaction

[butcher]

I would make sure the solution is slightly acidic, now you can cement the gold out of solution, use a large clean thick piece of copper, a copper buss bar from an electrical panel is best, but you can use a piece of clean copper pipe, a six inch long piece of 2" copper can be cut long wise with a pair of large tin snips or hack saw, the pipe unrolled and using a hammer flattened out, you also can punch a hole with a nail and a hammer, this gives you a place to hang it with a copper wire if needed, when you add the copper metal to an acidic solution containing the gold, gold will cement out of solution as a black powder, some of the copper will dissolve into solution pushing out, or replacing the gold from solution, when all of the gold is out of solution and there is no more free acid the copper will stop dissolving into solution, after there is no more reaction brush off the copper copper into the solution cleaning the copper bar, you can put it back into solution and if no more black powder forms on the bar the gold should be out of solution, a test with stannous is also recommended, although the green copper solution may mask a slight violet reaction making it hard to tell, when done brush of the copper again, let powders settle, carefully decant solution, dirty gold powders do not settle well or stay settled well, dry the gold and save it to take to Arizona.

The solution you can add iron to it to replace the copper from the solution cementing it out of solution as you did the gold above, decant iron solution from the powdered copper and dry the copper powders, with the iron solution bring it up to pH 9.5, let it settle decant solution from iron and base metal hydroxide sludge, bring the decanted solution back down to pH7 let it settle again, if anything precipitates, decant the now salt water, which is safe to dispose of, dry the sludge powders, heating the dried hydroxide powders strongly will make the safer oxides for waste disposal.

 

[das schnellste]

I used a copper heat sink from a CPU. It seemed to work well, but the heat sink disintigrated very fast. I went through three of them. I am drying the powders now and I used aluminum foil to retrieve the copper out of the leftover solution. I realize the solution still has aluminum in it, but I don't know how to get the aluminum out of it, or if I actually need to remove the aluminum from solution.

 

[butcher]

Add sodium hydroxide to make aluminum hydroxide, and let the fluffy powders settle from the salt water.

Aluminum hydroxide is a very fluffy goop, very hard to dry, Iron is a better choice much easier to deal with.

In the safety section one of the must read topics is dealing with waste, situations to avoid, the elephant in the room is also a very good read.

If you dissolved a lot of copper to cement, this is an indicator you are using way too much acids, there are many posts discussing limiting the acid and about how much acid is needed with how much metals, this will be another topic to study to get a better understanding, to help keep you out of a lot of the problems from overuse of acids, it can also save you some money.