Does Nitric Acid dissolved Gold powder?

[Franciz]

I have precipitate some gold from my Cyanide solution and wash with 50/50 Nitric acid, After washing the powder i left with some brown powder.
I try to soak the powder(GOLD) in 68percent nitric acid for 5-6hr, The solution turn yellow.
Do you guys think it dissolved some gold because i have read hoke's book and many thread in this forum its say nitric acid will not dissolve gold?

Thanks
Francis

 

[Franciz]

From what i understand it turn yellow because of NO2 gas in the solution, But i just wanna make sure this theory that nitric will not dissolve gold even when it is hot.

 

[Palladium]

No nitric acid alone will not dissolve gold. You should use hcl for your washes. Do not use nitric and then rinse with hcl without first incinerating your material again.

Search the term stannous chloride :?:

 

[philddreamer]

Search the term stannous chloride

Indeed!

Franciz, you would have had an answer before even posting, if you would have tested with stannous Cl. It's a must if your going to be refining!

Take care!

Phil

 

[Franciz]

Thank you, I now can confirm. Nitric alone cannot dissolve any gold.... :lol: :lol: :lol:

Thanks....

 

[Oz]

How in the world did a thread about material cemented from cyanide get this far talking about adding acid or testing with stannous chloride without someone warning about it generating HCN (hydrogen cyanide gas)?

Franciz, you may know the dangers already and have a fume hood and proper safety gear, but I do not want to leave a thread open like this without the warning. All cyanide must be destroyed before acidifying or testing with stannous chloride!

 

[Dr. Poe]

Oz is totally correct, but not the rest of you. Finely divided gold will not dissolve in diluted or hot nitric acid (0ver 70 Celsius)
But finely divided gold will dissolve very, very slowly in cold concentrated nitric acid (grams per year) just enough to color the solution yellow over time. Remnants of gold cyanide will also convert to HAu(NO3)4 releasing hydrogen cyanide and turning the solution yellow. You'd best take heed to Oz's warning. Dr. Poe

 

[butcher]

Dr Poe,
You say :
"finely divided gold will dissolve very, very slowly in cold concentrated nitric acid (grams per year) just enough to color the solution yellow over time. "

I have not heard of this before, if it is fact it is indeed interesting, but for what we do I do not see it as relevant.


I do not understand why I should be concerned with the above statement.
I would not have finely dissolved gold stored for years in concentrated cold nitric acid.
The only time I would use concentrated nitric on gold is when I am making Aqua regia, and then it is my goal to dissolve gold, and unless I was trying to hide the gold from the Nazi troopers I would not store it this way for years.

Dilute nitric is used to remove base metals from gold, and this process is accelerated with heating.

So basically I say gold will not dissolve in nitric acid alone, unless chlorides were involved, I say this also so as not to confuse new members, who are trying to learn.

 

[Franciz]

How in the world did a thread about material cemented from cyanide get this far talking about adding acid or testing with stannous chloride without someone warning about it generating HCN (hydrogen cyanide gas)?

Franciz, you may know the dangers already and have a fume hood and proper safety gear, but I do not want to leave a thread open like this without the warning. All cyanide must be destroyed before acidifying or testing with stannous chloride!

Hi Oz,

I know the danger of cyanide, I always wash the cemented powder many times and very well with hot water before i treated it with nitric acid...

Thanks you for your advices...

Francis

 

[Dr. Poe]

Dr Poe,
You say :
"finely divided gold will dissolve very, very slowly in cold concentrated nitric acid (grams per year) just enough to color the solution yellow over time. "

I have not heard of this before, if it is fact it is indeed interesting, but for what we do I do not see it as relevant.


I do not understand why I should be concerned with the above statement.
I would not have finely dissolved gold stored for years in concentrated cold nitric acid.
The only time I would use concentrated nitric on gold is when I am making Aqua regia, and then it is my goal to dissolve gold, and unless I was trying to hide the gold from the Nazi troopers I would not store it this way for years.

Dilute nitric is used to remove base metals from gold, and this process is accelerated with heating.

So basically I say gold will not dissolve in nitric acid alone, unless chlorides were involved, I say this also so as not to confuse new members, who are trying to learn.

Yes, I know, it's not a big deal. It just explains the coloring. Doc

 

[AlZabrisky]

Poe, you obviously dont have the authority to say oz is correct, I am sure he precedes you in precious metal refining knowledge. As well as, please dont belittle the members here by telling them they are wrong, you again dont have that authority.
I have reviewed many of your posts and I conclude that you attempt to dazzle others with bs. Your efforts appear to be devious and misleading and trying to corrupt those of us who are simply trying to stick to known science, something you have not respected. Are you attempting to prey on the lesser educated for monetary gains??.
Your claim to doctoral success in geochemical research is baseless and unfounded. A search of data bases of institutions across north america have revealed that your "PhD" is non existent. Please help clear this up by giving details of this "thesis" and where it was acheived. Until then, I urge everyone to ignore the fantasy science of Poe.
PhD is hard work and your claim to "Dr" may be a mockery to those who actually acheived this academic standing.

 

[publius]

Poe, you obviously dont have the authority to say oz is correct, I am sure he precedes you in precious metal refining knowledge. As well as, please dont belittle the members here by telling them they are wrong, you again dont have that authority.
SNIP...

My understanding of chemistry is such that what Poe has said is correct. and No, I do not have a PhD, an MS, nor a BS in chemistry.

I am risking stepping on my own winky here, but you are the pot calling the kettle "black!" Until you make Moderator status (like Butcher) perhaps you should address this issue to those that control the forum. Just my 0.02 USD

 

[AlZabrisky]

Winky? LOL.
in these modern times, kettles are electric and are not likely to get "black".

 

[nickvc]

Gentlemen please let's have calm.
Whether the good Dr is correct will be proven on here by those with the knowledge to either challenge or support his comments, to me he seems to have an understanding of the finer points of chemistry as relating to precious metals, their recovery and refining. If he is correct or incorrect you can lay your money on it been proven here on the forum, I gave the Dr an unfriendly welcome but having read the moderators replies I apologised, we need all the experts we can gather who will freely give their knowledge and I hope Dr. Poe is one of them and will continue to help the others who need his specialized knowledge.
If anyone can add something constructive to this fracas either for or against please step forward.

 

[butcher]

Let's not get into this, all over again.




Franciz,
I do not use, or am I knowledgeable about cyanide, I really do not know, but other metals salts like metal chlorides you cannot remove the chloride by simple rinsing, I would not think you could remove cyanide by simple rinsing, I would think heat or acid (forming deadly gas), or something else would be needed to break the bond, hopefully a member more knowledgeable will add his thoughts.

 

[nickvc]

Cyanide is water soluble but even so I'd wouldn't advise anyone to mix any powders from cyanide solutions with acids without a good fume hood, the consequences could be fatal.
I stress every time cyanide is mentioned this is not for the home or amateur refiner, please use other safer methods outlined on the forum if you are not fully equipped to deal with it.

THERE ARE NO SECOND CHANCES WITH CYANIDE....

 

[Palladium]

Some of the best members we have here on the forum has been bashed, crucified, and nailed to a cross at one time or another including me. The one thing all these people have in common is that they remain and stick it out regardless of what other may think or say. I to have had questions about the good doc from time to time and the way he presents his information and the validity of that information. With the brain power available to this forum if he presents information that is not correct it will be challenged and corrected by those with equivalent brain power. The one thing that is obvious is that the man has knowledge and that I have to respect. I’ve worked with many a people I can’t stand to even hear talk or be in the room with, but the one thing I have learned is to respect their knowledge. If the good doc is not what he appears to be it will come to light. Until then all I can do is observe and question. I might even learn a thing or two when I approach it with an open mind instead of condemnation.

 

[Harold_V]

I'm constantly amazed at the ability of readers of this forum to disagree, even get a little testy, and yet remain mannerly.

So long as this thread doesn't spin out of control, I will remain silent.

Harold

 

[maynman1751]

I'm constantly amazed at the ability of readers of this forum to disagree, even get a little testy, and yet remain mannerly.

So long as this thread doesn't spin out of control, I will remain silent.

Harold

I can't agree more Harold. We all should be adults here and respect each other and be able to have an intelligent and peaceful debate without lowering ourselves to inflammatory or unnecessary, insulting statements. These types of 'confrontations' can indeed be knowledge sharing experiences and be beneficial to the forum as long as they are done in a professional manner.

 

[publius]

Winky? LOL.
in these modern times, kettles are electric and are not likely to get "black".

I was going to say "Richard" but I thought I would run afoul with the Moderators.

Still, water is the "universal solvent," and it is my understanding if you place a substance in water, hot, cold, under pressure or not, some of that substance will go into solution.

Pot an Kettle... Like the sow calling the boar dirty (or dinner)... Better? :roll: