skaus said:
Just did my first AP wash on some fingers from RAM left it for 1 weeks and added extra proxide over 2 days to make sure all the gold was stripped off the RAM. I filtered the foils out of the mix which when filtered look ok could see lots of gold foils in the mix, but once it started to dry it looks really green, with a few bits of gold. Thought it might need to be better washed so i used a spray bottle to wash the foils (Still in the same coffee filter) The greenish color went away leaving the nice looking gold foils. Sadly again the greenish color come back when the foils dried out abit.
If you left your solution out for 1 week, then added peroxide over 2 days but did not add anymore water into your solution, your solution is probably far too pregnant to have dissolved all of the copper, but your gold foils did come off the board. They probably still have copper associated with your gold foils, so no matter how many times you wash it, the copper is going to oxidize and turn green.
You need to add water to your solution even if that means removing solution to add more water then you need to filter the solution you remove, and test with Stannous to make sure you have no Au dissolved into solution. Because your solution was left a week, it should have either eaten all the copper, or become too pregnant to take anymore copper into solution.
Because you added Hydrogen Peroxide over two days, you may have elevated the oxygen in solution to the point it dissolved some of your gold foils, then when more copper was dissolved it precipitated as Au sand. That might have retained some of the solution, if you didn't wash it thoroughly then whatever copper was not washed out of the same, would oxidize and turn that green color.
I Would wash the foils again, this time make it extra good, and filter through a new filter. Sometimes copper is actually retained in the filter and when it dries it gets drawn up the sides of the filter. If you see that, it means you didn't spray down your filter good enough. Use a new filter so you know that it has not been contaminated with copper from a previous wash. If you still see that green color, then I would assume that not all the copper was dissolved into solution. Since you are trying to separate as much from your gold foils as possible that is not gold, before you move on to the refining process, I would put the foils through AP again to dissolve the rest of the copper, or if you have Nitric Acid, you can dissolve the rest of the copper with a nitric acid wash. Just make it 50/50 and that should do the trick. But make sure the foils are washed really good before you wash in nitric acid, you should go ahead and incinerate at this point to insure there is no more hydrochloric acid associated with the foils, and the oils off your fingers is burned off. Then wash in Nitric Acid, and move on to your refining process, of your choice, from that point forward.
I rubbed the gold foils covered in green which transfer to my fingers (washed off with ease afterwards) not sure how to remove the green powder or what it is.
Whenever you touch your foils, or material with your bare fingers, you are transferring oils into your process. One of the reasons when people precipitate, and see floating gold crystals on the top of their solution is because of body oil that was introduced into the solution somehow. If you have to touch it, wear your gloves, plus there might still be acids that could harm you, even though you think it's washed.
A pic is attached i hope to make it a little easier to help out.
Did some searching first and come across this post and was wondering if it is the same problem i'm having expect in a large fashion.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=14281
The green in your filter is not soldering mask, that's copper oxidizing I suspect. The thread you are referring to is talking about soldering masks that are applied to PC boards to protect them from oxidation and humidity, etc. It wouldn't dissolve and then dry as an oxidant.
Should i try to do the AR wash next with an SMB drop x2 if the solution is greenish rather than yellowish ?
If you used AR at this point, you would be introducing copper into AR and would need to refine a second time to attain high purity. If you do as I suggested with the Nitric Acid, or if you put it through AP again, and remove the rest of the copper then you are starting your reffing process at least 22k, which makes the probability of precipitating high purity gold on your first AR process, far more likely. I Would still do AR a second time, but still believe the right thing to do is to remove as much base metals in the recovery processes, before you move to the refining process.
Also if some of the gold doesn't dissolved do i add my Cl to the HCL until all the gold foils have disappeared ?
Are you using AR, or are you using HCl/Cl to dissolve the gold foils? Or are you sure what it is you are trying to do?
Scott
