# Red & Black Powder?



## chucknorrium (Jul 8, 2011)

Hello guys, 
I'm a newbie and desperately wish to learn anything about PGM processing. I've been dealing with gold & silver only for a while, and have almost no experience when dealing with PGMs. My questions are probably going to be stupid, but I really need explanations from the experts  .

A while ago, a friend gave me 55gr of red powder (he said it was Pt) and 107gr of black powder (he said it was Rh).

Is that even Pt? I've seen bright yellow precipitation result of chlorinated Pt, but red? 
Carelessly, I torched (only) 5 grams of the red powder hoping to convert it into Platinum sponge (added small amount of borax in the process), the result shows no trace of metal, only blackened borax at the bottom of the porcelain dish  . Can somebody give me any information about this?

About the black powder, a friend confirmed that it was indeed Rh. So, I plan to boil some of it in 85% sulphate solution to make Rhodium Sulphate and sell it as concentrate for plating because most of jewelers in my country are probably too lazy or do not know how to make their own Rhodium Sulphate. The question is: Are there any better/safer ways to make Rhodium Sulphate?

Thanks for reading my post. I would really appreciate every bit of information.
Regards, Mo


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## Ian_B (Jul 8, 2011)

you need to calcine the PGM salt to a sponge trying to melt the salt will only turn your PGM's into vapour

Edit to add, I do not recommend trying to melt PGM's in porcelain dish's they cannot take the heat required to melt the metal and will crack/break/shatter


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## chucknorrium (Jul 8, 2011)

Ian, thanks for correction

I will try it below the melting point. The problem is, I don't have a kiln/furnace.
I guess I'll add some water to give it some moisture and torch it using small flame so i won't blow the metal away...


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## Ian_B (Jul 8, 2011)

are you talking about the Rh in the last sentance or the Red powder because the red powder will dissolve in water, it is a salt similar idea to table salt it will dissolve in water

http://www.youtube.com/watch?v=_9QprlWA-xM&feature=related if you have stannous chloride test the red powder by putting a small pinch onto a cue tip then adding a drop of Stannous Chloride to it, if it turns orange like in the picture it is a Platinum salt if it turns Orange then Green or straight to green it is a salt of Paladium.

if you want to convert the salt back to metal here is a clip from a member here doing it

http://www.youtube.com/watch?v=neR5qMNIS78


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## skippy (Jul 8, 2011)

I wish my friends would give me a few ounces of Rhodium! 8) 

PtCl4 is a red brown powder, which may be what you have. It won't calcine well in the atmosphere, or under borax. It has a certain tendency to volatilize when heated. Did you produce any colored smoke when you applied the torch to the red powder? The salt that you calcine is ammonium hexachloroplatinate, as it calcines much with only tiny losses. It is produced by adding a modest excess of concentrated ammonium chloride to a concentrated solution of chloroplatinic acid. Chloroplatinic acid can be made by adding HCL to PtCl4 - if PtCl4 is what you have.

If you do have that borax still, I would keep it, as the blackishness just might be your platinum. 

I believe that the sulfuric acid method is the easiest method of dissolving rhodium. It works, although takes time. I don't think it is unreasonably dangerous as long as precautions are followed. 
I believe Lou here recommended it, and he's probably got the most experience of anyone here when it comes to Rhodium.
There are fusions with sodium or potassium pyrosulfate, you can mix it with salt and then attack it with chlorine gas at red heat. Hot concentrated aqua regia will eventually dissolve it. Chlorination and hot AR don't give you the sulfate though.


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## chucknorrium (Jul 9, 2011)

Thanks for the link, Ian, the video was really helpful. I suppose I can use the same calcination method for the red powder. But the my red powder is almost identical with the paladium shown on the video... could it be palladium instead of platinum, or both material just simply have same color? I don't have stannous to begin with, and it's not available in shops here, is there another method to do the test?


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## chucknorrium (Jul 9, 2011)

skippy said:


> Did you produce any colored smoke when you applied the torch to the red powder?



does white smoke counted as "colored smoke"?
by the way, great explanation, skippy

as for the Rh, I guess I'll stick with the sulfuric acid method. is there a chance that the Rh will volatilize with the SO3 fumes? I'd like to minimize the loss, because however the Rh is actually still belongs to my friend.  . he just asked me to process it.


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## Harold_V (Jul 9, 2011)

Under the worst conditions I could imagine, none of my platinum ever came down in a color that could remotely be confused with the color of palladium. Palladium will be various shades of scarlet red, darkened, like platinum, when it is recovered from dirty solutions. The color of platinum, in all my experiences, ran from orange through yellow. 

I do not recommend you calcine the platinum metals in an electric furnace. The resulting fumes are very corrosive, so you can expect a rapid decline in the condition of the coils. A Fisher burner (large burner, like a Bunsen burner) will provide adequate, gentle heat. A fused quartz dish is advised, but one made of Vicor can be used with reasonable success. This is best carried out in a fume hood. 

Harold


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## Oz (Jul 9, 2011)

Harold_V said:


> Under the worst conditions I could imagine, none of my platinum ever came down in a color that could remotely be confused with the color of palladium. Palladium will be various shades of scarlet red, darkened, like platinum, when it is recovered from dirty solutions. The color of platinum, in all my experiences, ran from orange through yellow.


This has been my experience as well. 

What I will add is that gaseous platinum group metals/salts can be very poisonous. I would never suggest calcinations of pgm salts without a proper fume hood.


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