What just happened - ar fingers did not dissolve

[galenrog]

Thank you, anachronism.

I have been forced by circumstance to require myself to test every solution at all stages of recovery and refining. Same with flow charts and numerous notes. Due to stroke I have, among other permanent problems, occasional memory and cognitive issues.

I can not afford to make assumptions. Knowing that at any stage of recovery or refining I could walk away for the night and upon returning could have only a vague recollection of what I was doing the day before. If I have either solids or liquids without notes attached, I have to treat them as unknowns and proceed accordingly. Even with notes attached, I still have to test nearly everything.

I do not post often, and rarely post concerning procedure due to above mentioned issues. When I do post I try to add to the conversation.

Time for more coffee.

 

[Grelko]

Upon turning everything off and uncovering the beaker, the gold dissolved.

Did the beaker have a spout on it?

If not, I'm wondering if having a watch glass over a beaker that doesn't have a spout, heated up, slows the dissolution of the foils down because of the increase in pressure? Slightly heating may have not been enough to raise the pressure enough to release any fumes. Once the watch glass was removed, everything worked normally.

Maybe the AR fumes not being able to mix with air slows the oxidation of gold?

Has anyone tried dissolving gold in a sealed, slightly pressurized container of AR?

 

[g_axelsson]

Adding more and more HCl to an already weak AR solution only makes it weaker by diluting the AR, thus slowing down the reaction even more.

Added hcl, knowing I still had a small amount of active nitric. Started stirring with magnetic bar. Nothing. Added 1 ml of nitric. Nothing.

Snoman, how much HCl did you add at the beginning?

In my case I added 2 ml, but in a beaker that would have been too little to be able to stir it with a magnetic bar. I think you added too much HCl at the beginning and created a really weak AR. So it was really dissolving the gold all the time but slowly, it was just timing that the foils finally dissolved when you removed the watch glass.

Look at the pictures in my thread and you'll see how small volumes I work with. The larger volumes you have the harder it gets to collect the gold and the more losses you make.

We have all walked this way, making mistakes. Even the professionals do their mistakes now and then, but they realize it faster and know what to do to recover from it. 8)

Göran

 

[snoman701]

Goran....

Too much. Probably 20 mL.

I started out in a test tube, then moved to a 100 mL beaker.

I think you are correct.

Gonna wait at least a couple days before I do anything more. I need to get the shop cleaned up and organized.

Thanks

 

[upcyclist]

And I don't know about the whole alloy foils thing... As far as I know almost all (or all) finger plating is pure gold (or very very close to it).

I don't believe you can plate an alloy--only elements. "14K Gold Plating Solution" that jewelers use refers to the fact that stuff has been added to make the resulting color of the plated article look more like 14K than the darker yellow of 24K. Since fingers are plated, that means any gold is pure gold.

Now, if there's no nickel barrier underplate, and the gold migrates into the copper, then I guess that results in what is technically an alloy (rose gold that's all rose and barely any gold, haha). But that's an edge case, and something easily solved with copper chloride leach or nitric--no inquartation necessary.

 

[Topher_osAUrus]

And I don't know about the whole alloy foils thing... As far as I know almost all (or all) finger plating is pure gold (or very very close to it).

I don't believe you can plate an alloy--only elements. "14K Gold Plating Solution" that jewelers use refers to the fact that stuff has been added to make the resulting color of the plated article look more like 14K than the darker yellow of 24K. Since fingers are plated, that means any gold is pure gold.

Now, if there's no nickel barrier underplate, and the gold migrates into the copper, then I guess that results in what is technically an alloy (rose gold that's all rose and barely any gold, :lol: :lol: haha). But that's an edge case, and something easily solved with copper chloride leach or nitric--no inquartation necessary.

Indeed.

Im not by my books right now, but, when I get back home I will look in Wise's Gold book, where he goes over plating solutions and their compositions and the colouring of them. I was sick as a dog yesterday and slept from saturday at 11pm until this morning at 530.. So, I am a day behind on my toll refine. But, when I get back to the books I will post on it, as it does have a plethora of good information on the subject matter (and ANY and EVERY other subject relating to gold...like, did you know dmg can ALSO ppt gold?...yeah..i didn't either -mind.blown.)

But, in the case of fingers, its pure gold deposited on the substrate (or darn close to pure)

Regards
Toph

 

[g_axelsson]

It is possible to plate alloys and gold plating on most connectors and fingers are one example. To add to the mechanical strength of the gold plate there usually is a bit of chromium or nickel included, less than half a percent. It increases the wear resistance over pure gold that is really soft.
... it's called "hard gold", who would have thought that! 8)
http://www.eurocircuits.com/blog/40-Gold-plating-for-edge-connectors

Gold flash on the other hand is only a protection against corrosion so that is usually pure.

Göran

 

[upcyclist]

Ah, good to know!

I like to get corrected often on here--it's a more active learning mode than just reading

 

[Topher_osAUrus]

Attached is a couple pages from E.M. Wise's Gold, on the electrodeposition of gold, there are a couple other pages as well. But this covers the colored gold deposits.. Another one (not shown) says its best suited for gold deposits *greater* than .25 inches... ...now THAT is some gold plating!



Sorry for the continued derailing of the thread.. I'm done now
(hopefully)