# How to extract silver from gold and platinum?



## suhailkhan8547 (Apr 5, 2011)

Can anyone tell me how to extract silver from gold and platinum? I just want to know about it. Is anybody there, who tells me what to do for it.


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## Barren Realms 007 (Apr 5, 2011)

You can run your material in nitric acid to remove the silver.


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## goldenchild (Apr 5, 2011)

Barren Realms 007 said:


> You can run your material in nitric acid to remove the silver.


 :lol:


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## 4metals (Apr 5, 2011)

Nitric isn't always selective for silver over platinum, if there is over 10 times more silver than platinum, the platinum will dissolve in nitric with the silver.


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## jeneje (Apr 5, 2011)

Hello,
4metals I through pt group metals had to be heated with AR to dissolve in solution.

Ken


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## Harold_V (Apr 6, 2011)

jeneje said:


> Hello,
> 4metals I through pt group metals had to be heated with AR to dissolve in solution.
> 
> Ken


What 4metals told you is correct. If you have an alloy of silver and platinum, both constituents will dissolve readily in nitric acid. You can make that determination yourself by dissolving some of the material and testing with stannous chloride. 

In order to recover platinum that is contained in silver, it is recovered from the slimes from a silver parting cell. 

Harold


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## suhailkhan8547 (Apr 10, 2011)

I have 70 grams of silver bar. I think that It has 14% of pure platinum. 
Now I want to know how much nictic acid I use to dissolve silver to get pure platinum.
Except it, You can give any other suggestion If you have................


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## Platdigger (Apr 10, 2011)

I believe you could run this bar directly in a silver cell.
And as Harold just said, the pt and also any gold should end up in the slimes.


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## Harold_V (Apr 11, 2011)

Platdigger said:


> I believe you could run this bar directly in a silver cell.
> And as Harold just said, the pt and also any gold should end up in the slimes.


The high percentage of platinum is likely to be troublesome, especially considering there's gold in addition. In order to successfully part in a silver cell, one may have to add a given amount of pure silver, to lower the overall percentage of non-silver material. As is typical of electrolytic cells, a silver cell will perform best when fed high purity. 

I'm speaking from experience in this regard. When I processed the silver that was recovered from my waste material, the platinum, palladium and gold was too high to part the silver successfully. The slimes accumulated as a hard crust instead of loose particles that shed readily. Even with hard scraping, it was difficult to part the anode. Had I known the percentage was so high, I'd have followed my own advice, but I had but one anode to part, so I just toughed it out once I was committed. 

Because of the heavy coating of slimes, I managed to deplete the silver in my electrolyte to the point where I began co-depositing palladium. I theorize that the silver was unable to penetrate the coating, although it was still very conductive. I liken the situation to one where silver chloride isolates gold alloy from AR, making it difficult to impossible to dissolve. 

While the percentage of palladium that was co-deposited was obviously quite low, it wasn't acceptable to me, so after parting the last of the heavily contaminated anode, I simply placed the  recovered crystal silver back in the cell, then added an anode on top to act as a connector. I re-parted the crystals, achieving an acceptable product. 

Harold


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## suhailkhan8547 (Apr 11, 2011)

Nitric acid did nothing with this silver bar which has approximate 14% pure platinum. 
Nitric didn't solute the silver part. I have left this bar about 3-4 hours in nitric acid. 
But it did not work. Is there anybody to tell me cheap and successfully way to do this. 
I want to extract platinum from silver bar at any cost. I am very eager to do this.
All information about my query has been mentioned above my post........ :?:


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## Platdigger (Apr 11, 2011)

Harold just gave you your answer. Looks like you are going to have to remelt, and add more silver.

"In order to successfully part in a silver cell, one may have to add a given amount of pure silver, to lower the overall percentage of non-silver material"


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## Lou (Apr 11, 2011)

Also consider that you're using a bar. It has very low surface area relative to its volume. If you could make it into shot, that would greatly help.

Generally, the less melting/shotting and mechanical manipulation you do, the better accountability and yield will be.


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## Harold_V (Apr 12, 2011)

Do note, also, that nitric acid alone does not dissolve silver well. You are best served using dilute nitric. In this case I'd advise distilled water----and modest heat if you don't get a quick reaction. 

You're wasting your time trying to separate platinum by dissolving with nitric. Did you not pay attention to what you were told? When you have silver and platinum alloyed, both will dissolve in dilute nitric, so you won't accomplish your task. 

Harold


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## goldenchild (Apr 12, 2011)

Harold_V said:


> When you have silver and platinum alloyed, both will dissolve in dilute nitric, so you won't accomplish your task.
> 
> Harold



Didn't know this. So the platinum won't drop as a sponge? How is platinum digested without HCL?


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## dcurzon (Apr 12, 2011)

dissolve Pt/Ag in Nitric 50/50 - adding enough Ag to increase the Ag content % to over 90%
cement with Cu
melt into Anode
part in silver cell
recover silver from cell
remaining slimes = possible Pt

i think?


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## Harold_V (Apr 13, 2011)

goldenchild said:


> Harold_V said:
> 
> 
> > When you have silver and platinum alloyed, both will dissolve in dilute nitric, so you won't accomplish your task.
> ...



In my opinion, no. Because both silver and platinum are in solution, if you tried to cement (using zinc flour, which would yield a sponge of sorts), both would come down. Lou may be able to shed a lot more light on this, as I am not a chemist. 

What would work is to precipitate the silver as silver chloride, which could then be washed relatively free of any contained platinum (still in solution). The resulting solution might then be concentrated and processed for platinum, recovering by zinc flour or precipitating with ammonium chloride. 



> How is platinum digested without HCL?


 I am unable to address that question, but know it to be true in practice. Lou may be able to provide the reason-----but if memory serves, it is discussed in Hoke's book as well. 

Harold


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## Oz (Apr 13, 2011)

dcurzon said:


> dissolve Pt/Ag in Nitric 50/50 - adding enough Ag to increase the Ag content % to over 90%
> cement with Cu
> melt into Anode
> part in silver cell
> ...



You are making life hard on yourself. If I understand this correctly you are adding silver to your Ag/Pt alloy to bring the Pt under 10% so the Pt will go into solution in nitric. Then after you digest your new alloy you are cementing it on copper. What have you gained, as both will cement on the copper? When you melt this cement into an anode you will have what you started with before you digested it in nitric.

Having said that, if you have a bar that is over 10% platinum and the balance is silver, just re-melting it and adding the required silver to get 10% or less Pt does not make it suitable for a silver cell anode. A 10:1 ratio of Agt should get all the Pt to go into solution with a nitric digest, but if you put that into a silver cell you will have a pacification layer build up on the bottom of your anode (as Harold said above) that will cause you much grief. If you want to alloy Ag/Pt for a silver cell I would not want the Pt over 3%.

On another note, readers should take to heart what Harold said about diluting concentrated nitric for silver. You can put a pure silver round into 70% nitric and it will just sit there and smile at you. Add a bit of water and it will digest with a vengeance. More or stronger is not always better.


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## dcurzon (Apr 13, 2011)

Oz said:


> dcurzon said:
> 
> 
> > dissolve Pt/Ag in Nitric 50/50 - adding enough Ag to increase the Ag content % to over 90%
> ...



Not making life harder for myself as i'm not the one doing it, just gave a brief outline of what (i thought) might possibly be the route to take. The OP suggested there was Au in the alloy as well as Pt/Ag, dissolving in Nitric would take the Au out of the alloy and leave it in the bottom of the Nitric, leaving just the Ag and Pt to seperate via silver cell.

i must point out that i am vastly inexperienced and the likes of Harold, GSP, LaserSteve, Oz and others between them seem to have come across pretty much every possible scenario and should be listened to!


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## Harold_V (Apr 13, 2011)

Oz said:


> On another note, readers should take to heart what Harold said about diluting concentrated nitric for silver. You can put a pure silver round into 70% nitric and it will just sit there and smile at you. Add a bit of water and it will digest with a vengeance. More or stronger is not always better.


Once again I am at the mercy of my lack of education, but those with questions about the addition of water to nitric acid being valid in the dissolution of silver should explore the hydronium ion. 

Harold


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## Oz (Apr 13, 2011)

Harold,
I come from the same school as you do. Reading, due diligence, cause and effect. I too have not researched the hydronium ion to the point I can wrap my mind around it. I would enjoy hearing someone with knowledge explain it, but at the end of the day I have heeded others advice and proven it sound by my own experiences as to nitric concentrations. 

Probably the greatest mistake made by those new to refining is too much nitric no matter the procedure or source.


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## Harold_V (Apr 13, 2011)

Oz said:


> Probably the greatest mistake made by those new to refining is too much nitric no matter the procedure or source.


I can not improve on that comment. 

Harold


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## Oz (Apr 13, 2011)

dcurzon said:


> Not making life harder for myself as I’m not the one doing it, just gave a brief outline of what (I thought) might possibly be the route to take.


A valid point, but if you are going to post something as a procedural outline you should be clear that you have no experience with the process you just posted, but are only speculating. 



dcurzon said:


> The OP suggested there was Au in the alloy as well as Pt/Ag, dissolving in Nitric would take the Au out of the alloy and leave it in the bottom of the Nitric, leaving just the Ag and Pt to separate via silver cell.


Yes, what you are suggesting is true, but still a waste of time and chemicals (in my opinion) as the silver cell will recover gold as solids as well as platinum. When using a silver cell the most important contaminates to watch are those that will go into solution and contaminate you silver crystal if allowed to get too high in concentration. The second most important thing is to keep your insoluble elements in the anode under about 3% in total or you will be scraping anodes. If you let the insolubles build up on your anode you will (in effect) have an inert anode that will deplete your electrolyte of silver causing the impurities in your solution (that otherwise would be safe in their grams per liter concentrations) to plate out on/with your silver at the cathode.


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## dcurzon (Apr 13, 2011)

thanks Oz. Every day is an education


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## Oz (Apr 13, 2011)

I hope you do not feel that I was trying to shut you down or sound hard. 

Trust me, I am still learning myself, and I am a newbie compared to some of the guys we have on the forum. You will never learn it all, and that is the fun of it!


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## dcurzon (Apr 13, 2011)

Oz said:


> I hope you do not feel that I was trying to shut you down or sound hard.
> 
> Trust me, I am still learning myself, and I am a newbie compared to some of the guys we have on the forum. You will never learn it all, and that is the fun of it!



not at all. there is so much to learn and such a vast combined knowledge here that i'm proud to be a learning member


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## butcher (Apr 22, 2011)

"Trust me, I am still learning myself, and I am a newbie compared to some of the guys we have on the forum. You will never learn it all, and that is the fun of it!" 
OZ

The more we learn, we find the more we need to learn.


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