# What just happened - ar fingers did not dissolve



## snoman701 (Jan 7, 2017)

I have some fingers that I know are higher yield. I wanted to determine yield per card.

I dissolved base metals with nitric acid. Removed and washed fingers. Decanted off excess liquid.

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

Knowing my hcl was old, I figured it had lost a bit of chlorine. I added more. Some gold went in to solution then stopped.

No problem...I can pick up more hcl Monday. I added more of the weak junk. Some more went in to solution.

Well, after a while I had more than 200 ml total solution for just some foils. I said the hell with it. Turned off the stir bar. 

Immediately upon solution coming to a rest all the remaining gold went in to solution.

So why does stirring the solution keep it from dissolving?


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## anachronism (Jan 7, 2017)

snoman701 said:


> I have some fingers that I know are higher yield. I wanted to determine yield per card.
> 
> On what do you base this deduction? How do you know what yield they are meant to be? How many finger boards are we talking about?
> 
> ...



Answer all these questions line by line please so proper advice can be given.


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## snoman701 (Jan 7, 2017)

Sorry...more info.

Basis of higher yield is based upon expectation and fingernail test. Fingernail yields a definite step, which very well could be nickel base. Boards are from 80's era mainframes. 

67-70% nitric, diluted with distilled water to approximately 30% to release foils. 

Finger material was washed of foils. Foils were not washed, just decanted. 

The acid was old. Very possibly previously diluted. It is stock I had that I use for pickling steel plate. The bottle has been left in the sun before. I assumed some of the chlorine gassed off. 

When I decided to wait until Monday to finish the dissolution with fresh hcl of known concentration all I did was turn off hotplate and remove watch glass. I was going to transfer liquid to a bottle. Upon turning everything off and uncovering the beaker, the gold dissolved. 

I have not tested any solutions with stannous, but they are all segregated at this point.



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## snoman701 (Jan 7, 2017)

Sorry...quantity of fingers is approximately 12 square inches. I had plenty of solid foil following the dissolution of copper traces.


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## Topher_osAUrus (Jan 7, 2017)

I saw no mention of heat. Just stirring.
Is it a heating stir plate?

If not, that could be the issue more so than your acid.


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## snoman701 (Jan 7, 2017)

Yes. Just enough heat to get a little condensation on the watchglass. 


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## aga (Jan 7, 2017)

Very confused by this question/post.

The title says 'What just happened - ar fingers did not dissolve'

When met with reasonable questions you said " Upon turning everything off and uncovering the beaker, the gold dissolved." which is in direct contradiction with your chosen thread title.

One of the trolls that inhabit SM would have posted something exactly like that, unaware that this particular forum is full of people who actually Do chemically refine precious metals on a daily basis.


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## snoman701 (Jan 7, 2017)

Yes...it is a direct contradiction. It did not dissolve as expected. Is that a better description? 

Any mod is more than welcome to change the title.

I'm just trying to understand why a stirred and covered aqua regia did not dissolve gold until stirring was turned off and the cover was removed. 

I've been a member for two and a half months and a "troll"? 


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## anachronism (Jan 7, 2017)

Snoman

You're still not doing the basic things you're meant to do. Knowing whether you have gold in solution is an essential test and even more so at your level in the learning process. I've said it before. Learn the basics and follow the procedures.


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## snoman701 (Jan 7, 2017)

Knowing whether I have gold in solution....I had gold foils spinning around in a beaker of aqua regia....Then they disappeared. So where else could they have went?

All I am trying to understand is why the reaction was delayed. 






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## aga (Jan 7, 2017)

snoman701 said:


> I've been a member for two and a half months and a "troll"?


I did not say that you are a "troll" and i appologise for the assumed inference.

Just meant to say that the post should not have been so self-contradictory, and the opportunity to save the Mods any work was when the title was typed like that in the first place.


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## snoman701 (Jan 7, 2017)

Ever walk away from a conversation and think of the perfect response? That's sort of how my brain works. 

I too looked at the title, after writing it, and thought, "that doesn't make any sense."

Unfortunately, that's my life. Thank you for the clarification. 

I have a better grasp on the processes than my questions allude to. This was the fourth time processing with ar. Once it started dissolving, it went as one would expect. 

There could be the possibility that the foils were an alloy of silver or palladium and gold, which I believe would then require inquartation. Stannous tests would confirm this....but I won't be back to the shop until tomorrow. 



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## anachronism (Jan 7, 2017)

snoman701 said:


> Knowing whether I have gold in solution....I had gold foils spinning around in a beaker of aqua regia....Then they disappeared. So where else could they have went?
> 
> All I am trying to understand is why the reaction was delayed.
> 
> Sent from my iPhone using Tapatalk



In order to track a recovery or a refine you need to be able to definitively quantify where your gold is at any given point in that process. Any person on this forum will agree with this statement because assuming where it is leads to tears. Trust me I know this. I have politely suggested that you learn the basics to this skill set previously and you seem to consistently have a problem with that so I am going to step away and let someone else assist you from here on in.


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## snoman701 (Jan 7, 2017)

No...you have alluded to processes twice. This time I followed goran's tutorial on processing fingers from a single card in almost an identical process. The only variable being the questionable strength hcl. 

I can't tell you how much I appreciate your responses, I just have no understanding of what process I am supposed to follow as I thought I was doing just that.

If it is necessary to test every solution, I absolutely will. I posted my query after I had already left the shop...and my response to you was short, but there is literally no other place the gold can be. With that, I understand the necessity of structure in something like this...and intend to perform stannous tests as soon as I return to the shop. 

If you give me processes that require standing on one foot while patting my tummy and rubbing my head, I'll follow it to a t.

Again, thank you for your help! I absolutely appreciate it.


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## g_axelsson (Jan 7, 2017)

What he is talking about is my refining of one finger board in this thread.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=23737

In that thread it only took me two ml of HCl and the nitric left after a quick decant / wash.
Why snoman didn't succeeded I have no explanation other than the conditions must have differed, bad or mixed up chemicals is the most probable cause.... or lack of patience. That's a very common newbie mistake.

If a reaction doesn't happen then adding a bit more chemicals could be warranted sometimes, but keeping adding more and more is only leading to a bigger mess, if something is wrong at the beginning, then stop and examine what, don't just run along blindly in the hope that another addition of acid would solve the problem.

Patience, grasshopper.  

Göran


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## Topher_osAUrus (Jan 7, 2017)

Stannous is essential. Especially in the beginning. That way you can see the resultant color, and know if the PM is in solution or if its still just base metal junk... and after awhile you can get pretty good at judging how much of a PM is in a solution (although I'd say stannous is more of a qualitative test than quantitative -but experienced personnel can get in the ballpark for the latter)

If I were to guess, I'd say you used up the majority of the nitric getting the base metals out, so there werent enough nitrate ions to make nitrosyl chloride to dissolve the gold... Once you added more nitric, you should have just gave it a little more heat -or time.
Time is a big one. Patience plays a huge part in purifying metals. But, its not like each and every one of us weren't in your shoes at one time.

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).

Regards
Toph


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## snoman701 (Jan 7, 2017)

It very well could have been a lack of patience. I was rushed, and previous ar dissolutions have went very fast. 

I'm sure that temperature played a part as well. It's cold. I have the thermostat set to 45 overnight, so that's where my nitric and hcl were likely at to start. As well as the fingers that had sat overnight. 

It very well may have been simply a case of me finally giving up right at the time I hit the threshold temperature. Once the reaction finally went, it went fast...but there had been some uptake earlier, which was quite odd to me. 

I'll start taking pictures next time. I think the visual helps some.


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## snoman701 (Jan 7, 2017)

And yes goran...very used to silver solder, where if it stops and there's still metal, it needs more acid or heat.


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## galenrog (Jan 7, 2017)

Snoman701 wrote "If it is necessary to test every solution, I absolutely will."

Please let me comment on this statement. While it is not necessary for those experienced in recovery and refining to test in every circumstance, for the beginner it is almost essential. By making testing a habit that I no longer think about, I rarely have an instance where I am puzzled when recovering gold. 

Another essential for me is to create a flow chart I can understand for each procedure. Trying to remember each step, or constantly referring to YouTube can easily lead to mistakes. If you have not yet done so, consider writing all steps for each procedure prior to attempting, including expected results along the way. By keeping these notes in front of you while you are performing each recovery and refining procedure, you may learn faster and better.

Small steps at first. First, small scale acquaintance experiments. Once you have a good understanding of each procedure, you will more easily scale up and will better understand expected results. 

And test, test, test. 

Time for coffee. Enjoy.


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## anachronism (Jan 7, 2017)

galenrog said:


> Snoman701 wrote "If it is necessary to test every solution, I absolutely will."
> 
> Please let me comment on this statement. While it is not necessary for those experienced in recovery and refining to test in every circumstance, for the beginner it is almost essential. By making testing a habit that I no longer think about, I rarely have an instance where I am puzzled when recovering gold.
> 
> And test, test, test.



Galen

Please excuse me for truncating your post but the comments above explain the need for testing perfectly. My thanks.


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## galenrog (Jan 8, 2017)

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.


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## Grelko (Jan 8, 2017)

snoman701 said:


> 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?


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## g_axelsson (Jan 8, 2017)

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.



snoman701 said:


> 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


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## snoman701 (Jan 8, 2017)

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


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## upcyclist (Jan 9, 2017)

Topher_osAUrus said:


> 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.


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## Topher_osAUrus (Jan 9, 2017)

upcyclist said:


> Topher_osAUrus said:
> 
> 
> > 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).
> ...



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


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## g_axelsson (Jan 9, 2017)

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


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## upcyclist (Jan 9, 2017)

Ah, good to know!

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


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## Topher_osAUrus (Jan 9, 2017)

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)


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