# Refining gold, silver and palladium together



## WillGreen (Dec 24, 2012)

Hello All, 

I think I know that you will say: read this and that, which is why I am posting this message. 

In a couple of weeks from now, I will have lemel (filings) of gold, silver and palladium 950 all together. 
It's together because I make mokume gane, so I fuse these metals together first and then I work the billet into rings. 
Could someone please point me to a source that I can use to understand how I can get all three metals back or can someone give me some explanation?
I know how to refine silver and gold, but now I do not even know how to begin. 

If this is too complicated - by all means, I am not a refiner - I am considering asking someone to do it for me, but I live in Ireland and this complicates things. 
Sending precious metals over is not very smart and once I start myself there is no way back - I can't send anyone a bottle of AR, the return address would be jail. 

With best regards, 

Will


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## nickvc (Dec 24, 2012)

Will, Hoke has chapters on how to deal with this material and I know you stated about not reading books but as this material is your bread and butter and were it me I would want to understand how to recover and refine it and if you think this is difficult wait till you try to refine your sweeps.
The one good thing is that lemel or jewellers bench sweeps are easy to dissolve because it's in small particles but with the mix it's not easy to separate into fine metals.
In my opinion you have two choices you either use nitric and dissolve the silver, palladium and some of the platinum or all if there's enough silver and leave the gold and possibly some platinum for further refining or you use dilute cold aqua regia and dissolve the gold palladium and some platinum if you work with it. 
If this was my material I think I would go with the nitric to avoid the silver chloride as the solution can be cemented with copper to recover all the values from the nitric after filtering or the solution can have table salt or hydrochloric added to form silver chloride which you can then filter off leaving AR with the palladium in which again can be cemented with copper to recover the values and the silver chloride can be converted by your method of choice. Refining the palladium to reuse is far from easy and it might well be a case of saving it until you have enough to make the effort worthwhile for either you or your supplier but you will be able to recover and refine your gold and silver with relative ease but I still think that a little study with Hoke will pay dividends whichever process you opt for.


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## WillGreen (Dec 24, 2012)

Hi Nick, 

Thank you for your input, but I do not understand where you get the idea from that I do not like reading books. 
I read Hokes and I am rereading some relevant chapters at the moment. 
Also, there is no platinum in my billet - the lemel will be gold, silver and palladium. In total, the palladium will come to 34,4 grams because that is all I have, so, as a wild estimate, I think that there will be appr. 14-15 grams of palladium which will end up as lemel - 50 % is usual when you make mokume gane; of course the palladium is not pure, it is 950 (the rest is copper). 
Normally, with gold and silver, it is possible to refine it myself, make a new ingot and go on making something new, but this is way more difficult with palladium - it's difficult to refine, difficult to melt, it's probably impossible to pour and make an ingot of it, so I do not know what to do right now, but I want to know before I start.

Merry Christmas, 

Will


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## lazersteve (Dec 24, 2012)

Will,

Adjust the alloy of your material to 6K gold (25% gold, 75% Pd/Ag) and cornflake the resulting alloy.

Treat the cornflakes with a 50/50 mix of hot nitric acid and distilled water to remove the Pd/Ag from the Au. Cover the reaction with a watch glass.

Pour off the leach solution, leaving the solids (gold) in the bottom of the beaker. 

Perform a second leach with straight 68% nitric acid at medium heat covered with a watch glass, until no more reaction (small fizzy bubbling) is seen.

Pour off the liquid and rinse solids well with several washes of distilled water.

Combine rinses with first two leaches (diluted and concentrated). Filter until 100% transparent and free of sediment. This liquid contains your silver and palladium. Your gold is the solid material in the bottom of the reaction beaker.

Refine the gold with AR as typical for 99%+ purity with proper technique.

Add a saturated solution of sodium chloride (NaCl ) to the combined leaches and rinses to recover the Silver as silver chloride, add salt water with stirring until no more curds of silver chloride clouds are formed. Vacuum filter and rinse AgCl repeatedly with *hot water* until the rinse water is 100% colorless and tests negative for Pd with DMG. Convert the silver chloride (AgCl) to silver metal using lye (NaOH), water, and sugar. 

Combine all hot water rinses with the colored (straw yellow to burgundy red) filtered salt water. This contains your Pd. 

Add enough 1% DMG solution to the combined colored liquids to precipitate the Pd as a fluffy yellow solid. Filter out the yellow precipitate and test the left over liquid for Pd using DMG. If positive add more DMG and repeat, until DMG test is negative on filtered solution. Thoroughly wash the yellow precipitate with a 1% solution of HCl while it is in the vacuum filter. Approximately two grams of dry DMG are required per gram of Pd.

Gently incinerate the resulting yellow palladium DMG compound under a hydrogen flame to red heat, until the entirety of the material turns light gray. Once the Pd sponge is formed, either melt into a button using the hydrogen-ox flame, or use the sponge as is.

Test the left over solution with stannous and DMG before properly disposing of the wastes.

Steve


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## WillGreen (Dec 24, 2012)

Dear Steve, 


Thank you very much. 
This is really enormously helpful, but would you mind if I would ask you some questions? 

I saw you mentioning the watch glass before, but I do not understand what the function of it is. 
Is it just to prevent spills? 

I am sorry for this dumb question, but I do not know. 

For the sodium chloride, is it possible to make it yourself using table salt, or do I need to buy it? 

(I checked our table salt a while ago and it contains ferro cyanide (to keep it dry?)). 

I am sorry, but I do not know what DMG is. 

As for the last step, I do not have a hydrogen torch. The only torch I have is an oxy/propane torch. 
Is that a big problem? 

Suppose I manage to melt the palladium into a button, is there any chance that, after alloying it with silver to palladium 500, I could melt it again and make an ingot which can then be rolled down etc.? 

If it is not possible to melt it with an oxy/propane torch, I am thinking of making a very small ‘kiln’ with some firebricks and burrying the palladium in charcoal in order to melt it. I have an electrical oven, but it does not go up high enough. 

Thank you again and merry Christmas to you! 

Will


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