Platinum > palladium > rhodium

[lazersteve]

I would like to add that brown is a stain you can get from stannous test if testing solutions that have been saturated with sulfurous acid (or any form of SO2). This brown stain may indicate the presence of Pd. If the starting color of the solution prior to the stannous test is already brown (eg high iron) then it may be a false positive. For conclusive testing of Pd always confirm with DMG when stannous results are in question.
I have a theory that the brown color comes from the formation of hydrogen sulfide by the reaction of the tin solution with the dissolved SO2. The hydrogen sulfide then reacts with the metals present in the solution being tested forming brown metal sulfides. Supporting evidence of this theory is the tell tale rotten egg smell of hydrogen sulfide (its more dangerous than hydrogen cyanide to inhale!!).

Be safe and good luck!

Steve

 

[Wonka]

This is from the green solution. I just did it. Been letting it saturate overnight.

 

[Wonka]

Here’s a pic of the solutions. You can’t really tell in the pics but the first one is a yellow/red. The second is green.

Edited: mixed the pics up.

 

[Wonka]

I would like to add that brown is a stain you can get from stannous test if testing solutions that have been saturated with sulfurous acid (or any form of SO2). This brown stain may indicate the presence of Pd. If the starting color of the solution prior to the stannous test is already brown (eg high iron) then it may be a false positive. For conclusive testing of Pd always confirm with DMG when stannous results are in question.
I have a theory that the brown color comes from the formation of hydrogen sulfide by the reaction of the tin solution with the dissolved SO2. The hydrogen sulfide then reacts with the metals present in the solution being tested forming brown metal sulfides. Supporting evidence of this theory is the tell tale rotten egg smell of hydrogen sulfide (its more dangerous than hydrogen cyanide to inhale!!).

Be safe and good luck!

Steve

It does have lots of sulfur in it, but I’m getting red salts. There is no rotten egg smell. Thankfully.

 

[Wonka]

It does have lots of sulfur in it, but I’m getting red salts. There is no rotten egg smell. Thankfully.

Hmm the refinery I’ve started working with buys mixed PGM metals. I’m starting to think it might be better to just drop everything and melt it all. With a solution with pyrosulfate and ammonium chloride in it, would sodium hydroxide still drop all the metals?

 

[Yggdrasil]

This is from the green solution. I just did it. Been letting it saturate overnight.

Gloves man, PGM salts are extremely toxic and it is accumulative.
We have members that died of Platinosis.

 

[Golddigger76]

These are stannous test of mine that are positive for palladium.
Palladium will show many different colors from green to brown to almost black in a highly saturated solution.

It's called the chameleon metal for a reason.

When you test for palladium don't try to immediately read the results but give it some time to fully react with the stannous chloride.

When I stannous test with a cotton swab I put a drop of stannous chloride where the cotton meets the stick and then dip the tip of the cotton into the solution that I am testing.

Then I set it to the side to let the two meet up in the middle.

For me it's what works best and I use the same method for testing for gold and all of the platinum group metals.

Edited to explain my testing techniques

 

[Wonka]

These are stannous test of mine that are positive for palladium.
Palladium will show many different colors from green to brown to almost black in a highly saturated solution.

It's called the chameleon metal for a reason.

When you test for palladium don't try to immediately read the results but give it some time to fully react with the stannous chloride.

When I stannous test with a cotton swab I put a drop of stannous chloride where the cotton meets the stick and then dip the tip of the cotton into the solution that I am testing.

Then I set it to the side to let the two meet up in the middle.

For me it's what works best and I use the same method for testing for gold and all of the platinum group metals.

Edited to explain my testing techniques

Thanks for the info! I really appreciate it. The reddish brown is what I would expect but the green just throws me off. And the fact that all the PGMs can be green under different circumstances/ concentrations just makes things worse.

 

[Wonka]

This looks like platinum salts correct?

Edit: when the bucket was heated it was a dark green. I shut the heat off and this precipitated over night and the remaining solution tests negative for anything and is a watery red.

Nevermind. I believe it’s ammonia sulfate

 

[Golddigger76]

What was the material you started with and was it dissolved in aqua regia ?