niels-chemist
Active member
How selective are DMG and iodide in precipitating *only* palladium? I start with 99.95% pure Pd and would like to increase its purity to 99.999% How hard is this?
Refining Pd and increasing purity
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Golddigger76
Well-known member
DMG is very selective but it is too expensive and to voluminous in my opinion.
How much refining experience do you have ?
niels-chemist
Active member
Would adding DMG to solutions containing ppm levels of the other noble metals (Pt, Rh, Ir, Re Ru, Os, Au, Ag, Re) result in any precipitate? The other option I see is using substoichiometric amounts of DMG, so you precipitate only 20 / 30 / 40% of the Pd in order to get that *very* pure. Then you can separate those crystals and precipitate the rest as a batch with lower purity.
Experience in refining: none, zero, nada
Experience in working in the fumehood doing synthesis and handling *very* toxic reagents: many many years.
DMG is selective for Pd, how selective I do not know.
Iodide-Iodine are used for dissolving PMs and I have not heard about it being able to drop PMs.
niels-chemist
Active member
I haven't really looked into it, but I suspect more advanced techniques are used for ultra-high purity refining. Possibly formation of soluble complexes followed by prepHPLC for separation?
Golddigger76
Well-known member
Platinum group metal salts are extremely toxic and can get inside your body through your skin and even lungs from the fumes that is why I asked how much experience you have in refining.
I don't recommend messing with Platinum group metal refining even with thorough laboratory training, not saying that you are incapable of learning only that you should start with refining gold and silver and then maybe work your way up to pgm's when you are very comfortable and fully understand.
The hardest thing for pgm's is to get full separation, Platinum and palladium like to follow each other along with gold and silver and that is why most people just send it out to a refinery.
I have never tried refining with iodine, it's on my bucket list to try but it will require extensive reading for me because I will not try any refining techniques or methods without fully understanding everything about it.
I have refined a lot of catalytic converters for Platinum and palladium and got decent results but I don't think that they are worth refining with acids using the methods that I know.
When I get my new lab set up I'll be trying some different ways but for now I am only refining gold and silver in a outside environment.
What is the materials that you are wanting to refine with palladium ?
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niels-chemist
Active member
Yes, I'm well aware of the toxicity of Pt2+ and especially Pt4+ salts. If you're careful, have experience, use proper PPE and work in a professional lab with a proper fumehood it should be fine to handle them on small scale. This is not so much the case for Os(VI), which is orders of magnitudes more toxic than Pt(IV).
What we want is to do palladium chemistry. We buy 99.95% pure palladium and one of my side projects is to refine it further to 99.995+%. That's why I'm looking into it a bit on how this can be one.
What we want is to do palladium chemistry. We buy 99.95% pure palladium and one of my side projects is to refine it further to 99.995+%. That's why I'm looking into it a bit on how this can be one.
goldandsilver123
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For this type of work, I would begin thinking what impurities must be totally eliminated, what's acceptable to be with the palladium.
Run an ICP-OES or ICP-MS to see your impurities, only then select the refining route.
Buying 99.95% Pd dissolving in Aqua Regia and precipitating with zinc will only increase the contamination.
if you want to refine 99999 Pd, i think every chemical used need to be pure like NH4CL, H2O, acid and so on. you can use hydrazine hydrate to reduce the Pd
Do it with an alkyl sulfide after careful removal of the gold and silver.
kurtak
Well-known member
Just curious as to why you want to try to achieve 5 nine Pd
Is it because you have found a market for 5 nine Pd that pays a HIGH premium over spot ?
Or just to say you did it ?
Or ???
Kurt
The purer a metal is, the more it is worth, besides it is nice to have ultra-pure metals.
Any reason no one mentioned electrolysis yet?
If he knew what the impurities are, would a three sided electrolytic cell be possible, just thought of this.
Any reason no one mentioned electrolysis yet?
If he knew what the impurities are, would a three sided electrolytic cell be possible, just thought of this.
In an ideal world it would be like this.
But when you are talking about ultra high purity, the documentation is what decides the acceptable "purity".
The documentation on a small lot may cost more than the actual metal, if I'm not mistaken.
And then it is the matter of finding a customer willing to buy a lot of your actual size, not always easy or even possible.
niels-chemist
Active member
I'm thinking about making a Pd complex that is air-stable and that you can crystallize from a simple solvent like acetone / water / heptane. I dont know any of these complexes from the top of my head, but I can look into it.
Maybe DMG2Pd is soluble in acetone / DMSO?
I know alcohols can be oxidized to their ketones by Pd2+ salts, giving Pd(0), so alcohols are not the ideal solvent for crystallization here (even though my favorite crystallization solvent for simple organics is isopropanol)
Maybe DMG2Pd is soluble in acetone / DMSO?
I know alcohols can be oxidized to their ketones by Pd2+ salts, giving Pd(0), so alcohols are not the ideal solvent for crystallization here (even though my favorite crystallization solvent for simple organics is isopropanol)
niels-chemist
Active member
Yes, documentation is expensive, so you are not going to do it on a batch of 1 gram ;-)
niels-chemist
Active member
Unfortunately I cannot comment on that ;-)
