Iridium/Platinum Refining

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darkminos

Active member
Joined
Jul 27, 2020
Messages
29
Hi!

Is there anyone on this forum who has successfully refined 20 Ir / 80 Pt alloy? I did briefly read somewhere about a method where the Pt content is increased to (if I remember correctly) 17 parts and then dissolved in AR.

Any books or links to a tutorial would be greatly appreciated as information regarding Ir refining is scarce! Perhaps someone can share their experience when parting those two metals?

Thanks!
 
If you don't have a time machine to work it with AR, alloy it with copper (>20%), roll it then dissolve in AR.
It's easier said than done.
 
Refining platinum is not easy as I have pointed out before and with iridium in the alloy it makes it even more difficult, using AR I believe would be a poor choice unless you do what the previous poster suggested and make the alloy much more dissolvable by adding a lot of copper which in turn means a lot more waste.
I can’t really help you on this as I stay well away from refining PGMs but I’m sure there are posts relating to processes that would help you here on the forum but you may have to do a little digging to find them, anything Lou has suggested would be worth reading and also our late and much missed freechemist, also the previous poster seems to have a pretty good handle on these materials but I’m afraid the list is fairly short of members who handle these materials regularly and with good insight to the processes that work and how to avoid making a complete mess.
I would advise you to put this stuff away and do a lot of reading and research before doing anything with it, you have to be fully versed on the processes and steps needed before you even experiment with a small sample.
 
nickvc said:
Refining platinum is not easy as I have pointed out before and with iridium in the alloy it makes it even more difficult, using AR I believe would be a poor choice unless you do what the previous poster suggested and make the alloy much more dissolvable by adding a lot of copper which in turn means a lot more waste.
I can’t really help you on this as I stay well away from refining PGMs but I’m sure there are posts relating to processes that would help you here on the forum but you may have to do a little digging to find them, anything Lou has suggested would be worth reading and also our late and much missed freechemist, also the previous poster seems to have a pretty good handle on these materials but I’m afraid the list is fairly short of members who handle these materials regularly and with good insight to the processes that work and how to avoid making a complete mess.
I would advise you to put this stuff away and do a lot of reading and research before doing anything with it, you have to be fully versed on the processes and steps needed before you even experiment with a small sample.
Click to expand...

That's why I asked about a good book on the subject and a nudge in the right direction :wink: not touching it before then.
 
goldandsilver123 said:
If you don't have a time machine to work it with AR, alloy it with copper (>20%), roll it then dissolve in AR.
It's easier said than done.
Click to expand...

Thanks for the tip! For me personally it's about getting the platinum into solution as painlessly as possible and leaving as much Ir at the bottom of the beaker as possible. If alloying the Pt/Ir with 20% copper and rolling it will speed up the process then I might try it! (is this 20% by weight of platinum or total weight of Pt/Ir alloy?)

And again, do you have a link to a book or tutorial or forum post where someone has attempted this method? I don't want to create an unworkable blob of material and then spend 3 weeks getting it back :wink:
 
That alloy can be chlorinated with sodium chloride and chlorine. Works very well.

Alternatively, it can be chlorinated by itself to form acid soluble PtCl4 and insoluble IrCl4.
 
Yep, about 700-750 centigrade is the temp I do these at.

Pt volatilizes somewhat but is soluble in dilute AR/HCl.
 
Lou said:
That alloy can be chlorinated with sodium chloride and chlorine. Works very well.

Alternatively, it can be chlorinated by itself to form acid soluble PtCl4 and insoluble IrCl4.
Click to expand...

Thanks for the reply Lou.

What if the carrier liquid for the Pt/Ir alloy was HCI? Would the Pt go into solution while reacting with chlorine gas, leaving only IrCl4 behing to be filtered out of the solution? Also would the same temperature range you mentioned still apply in such a scenario?

Or would you say that the best method would be to reduce the alloy by chlorination to PtCl4 and IrCl4 and treat it with AR afterwards? Dissolving PtCl4 into solution, filtering out IrCl4, and precipitation of the chloroplatinic solution with ammonium chloride?

Sorry if I got the wrong end of the stick, it's a steep learning curve for me 😅
 
darkminos said:
Lou said:
That alloy can be chlorinated with sodium chloride and chlorine. Works very well.

Alternatively, it can be chlorinated by itself to form acid soluble PtCl4 and insoluble IrCl4.
Click to expand...

Thanks for the reply Lou.

What if the carrier liquid for the Pt/Ir alloy was HCI? Would the Pt go into solution while reacting with chlorine gas, leaving only IrCl4 behing to be filtered out of the solution? Also would the same temperature range you mentioned still apply in such a scenario?
No and No.
Or would you say that the best method would be to reduce the alloy by chlorination to PtCl4 and IrCl4 and treat it with AR afterwards? Dissolving PtCl4 into solution, filtering out IrCl4, and precipitation of the chloroplatinic solution with ammonium chloride?
That can be done, if the material is high enough in surface area.
Sorry if I got the wrong end of the stick, it's a steep learning curve for me 😅
Click to expand...
 
Lou said:
darkminos said:
Lou said:
That alloy can be chlorinated with sodium chloride and chlorine. Works very well.

Alternatively, it can be chlorinated by itself to form acid soluble PtCl4 and insoluble IrCl4.
Click to expand...

Thanks for the reply Lou.

What if the carrier liquid for the Pt/Ir alloy was HCI? Would the Pt go into solution while reacting with chlorine gas, leaving only IrCl4 behing to be filtered out of the solution? Also would the same temperature range you mentioned still apply in such a scenario?
No and No.
Or would you say that the best method would be to reduce the alloy by chlorination to PtCl4 and IrCl4 and treat it with AR afterwards? Dissolving PtCl4 into solution, filtering out IrCl4, and precipitation of the chloroplatinic solution with ammonium chloride?
That can be done, if the material is high enough in surface area.
Sorry if I got the wrong end of the stick, it's a steep learning curve for me 😅
Click to expand...
Click to expand...

Thank you for the clarification 🙂
 
darkminos said:
Lou said:
That alloy can be chlorinated with sodium chloride and chlorine. Works very well.

Alternatively, it can be chlorinated by itself to form acid soluble PtCl4 and insoluble IrCl4.
Click to expand...

Thanks for the reply Lou.

What if the carrier liquid for the Pt/Ir alloy was HCI? Would the Pt go into solution while reacting with chlorine gas, leaving only IrCl4 behing to be filtered out of the solution? Also would the same temperature range you mentioned still apply in such a scenario?

Or would you say that the best method would be to reduce the alloy by chlorination to PtCl4 and IrCl4 and treat it with AR afterwards? Dissolving PtCl4 into solution, filtering out IrCl4, and precipitation of the chloroplatinic solution with ammonium chloride?

Sorry if I got the wrong end of the stick, it's a steep learning curve for me 😅
Click to expand...

Just caught this and wanted to correct: PtCl4 yes, and IrCl4 not so...it's green IrCl3.
 
How about melting with silver then dissolve silver bead in nitric? Platinum will dissolve in nitric and Ir will be left as black powder.
 
It may work, but we do not know if nitric acid attacks platinum well, and it may also remain as an undissolved black powder and remain at the bottom with iridium. who could do this?
 
I know Pt will follow Pd when dissolved in Nitric,
but how complete I do not know.
I don't know if this is true with Silver as well.
Maybe the Lou or the other masters can chime in
with some enlightenment here.
 
4metals said:
Classic fire assay texts say the Silver content needs to be 10x the Platinum content for the Platinum to follow the Silver into nitric.
Click to expand...
Fire assay and wet chemistry are quite different. I do rely on silver as a solvent to clean my gold as a nitrate. But tend to use the wet rather than hot.
 
Justin, please explain your use of silver nitrate to clarify your statement.

The reason the old fire assay texts use added silver in cupellation is to take small amounts of Platinum in a sample into the nitric parting acid with the Silver and allow the gold to remain in the cupel without Platinum contamination.

I’m not thinking what you said is anything similar. Please clarify.
 

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