Obtaining iridium from a polymetallic powder

[g_axelsson]

What I meant is to use a transparent separator funnel with a minimal amount of mercury, by way of experiment and see whether something settles below - Ir of course is heavier than mercury, just to prove Ir is present

Well this a unique test. But the way I learn is to read, understand the concept, and approach this with an open mind. I wonder if the surface tension on the surface of the mercury pool would make a small quantity of even a more dense material float on the surface? Creating a false negative.

Most probably, surface tension is quite high for mercury, just watch how it balls up whenever some is spilled.
It would also be impossible to extract it from the other powder as solid particles seldom moves inside a powder even if it is heavier. You need to levitate it in some way, for example panning is levitating the gold and sand in water, drypanning is using air.

Göran

Which way do you recommend me to levitate it? Or some chemical method to eliminate the high percentage of iron?

I don't, the obvious way to separate it is panning but that only works if the powder is relatively coarse and the particles are pure iron or iridium.

It almost sound like it's saw dust from cutting meteorites. If it is then it's all mixed together in an alloy and any gravimetric method will fail.

If you have access to cheap acid then dissolving the iron in sulfuric or hydrochloric acid might work. It will create a lot of waste though but concentrate the iridium.

But the real question is what it is you have? Obviously it isn't iron powder or it would have been attracted to the magnet. It has to be some compound of some sort and not metallic.

I have no experience of working with iridium so anything I write you better check with second sources.

Göran

 

[Lino1406]

XRF on powders is very unreliable. However only for curiosity I would make an experiment with a fine powder and mercury or panning as suggested. If the result is positive - meaning the Ir reading increased thereafter (which I doubt) we'll continue from there

 

[geedigity]

XRF on powders is very unreliable.

I think noobsk indicated that he was also given additional analytical results (Atomic Absorption) and concentration of Ir was confirmed to be .4 to 2 grams per kg.