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Author: Subject: Iridium
neutrino
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[*] posted on 13-1-2006 at 21:28
Iridium


I want to do a little experimenting with this fascinating metal, but I have run into a problem: I can't find it for a decent price. The current spot price is $6.27USD/gram, but the cheapest I have been able to find it is $16/gram + $25 shipping and this was on eBay! The Thomas Register doesn't list any better sources, nor does froogle. I won't even mention chemical suppliers' prices...

What's the cheapest way to get a couple of grams of iridium? (The physical form doesn't matter.) I've come up with nothing here and will gladly take any suggestions.
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[*] posted on 14-1-2006 at 02:28


What kind of expriments are you thinking of with the iridium? I have a source in Germany for powdered iridium at EUR 8 per gram (appr. $10 per gram), minimum offtake 5 grams, but I did not buy it yet, because I have not found any way to chemically dissolve this metal. If I just have some powder, which does not dissolve in anything, then of course, it is not worth the money.
If you wish, I can lookup that source for you. One year ago, I purchased 5 grams of ruthenium powder as well from that source for appr. $8 per gram. I do not know, however, what shippings costs you will have (I live in the Netherlands, next to Germany, so I only had to pay EUR 2 or something like that for postage, for you it will be more, due to overseas shipping). With the ruthenium I indeed have done very interesting experiments, some of these are on my website with pictures.

These spot prices, you mention for the noble metals, usually are for large quantities (at least one ounce or something like that). Smaller quantities become progressively more expensive.

So, if you know of a method to dissolve the metal chemically in an aqueous solution (not a molten alkali, for that I have no safe possibilities where I live), then I would be very pleased.




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[*] posted on 14-1-2006 at 09:39


I was going to try some things to dissolve the stuff. Fenton's reagent (pH 3) + chloride was first on that list, then maybe persulfate (acidic, if possible) + chloride. Nitrate + hydroxide in a nickel crucible if all that failed... It's worth a try.

How old is that price? I know that precious metal prices fluxuate wildly.
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Eclectic
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[*] posted on 14-1-2006 at 11:25


The current spot price is about $200 per try oz. (about 31g).
I had to buy 5 oz @$225/oz for my experiments in recreating the One True Ring. Since I don't have access to the fires of Mount Doom, I'll have to use an electric arc.
As far as I've been able to determine, Ir is imperveous to ALL acids, including HF/HNO3 and aqua regia. It will react with molten sodium peroxide and then with HCl to form the chloride.
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[*] posted on 14-1-2006 at 12:31


Quote:
Originally posted by Eclectic As far as I've been able to determine, Ir is imperveous to ALL acids, including HF/HNO3 and aqua regia. It will react with molten sodium peroxide and then with HCl to form the chloride.



Iridium catalysts are made from either Ir(III) acetate or IrCl3.xH2O, the latter being used as precursor for many ligand Ir complexes (COD, Ph3P, ...). Ir(III) acetate is made by reacting iridium metal with barium peroxide in the presence of EtOH/HOAc at very high temperatures. To make Ir(III) chloride hydrate salts, iridium metals is fused with NaCl under an atmosphere of Cl2 at very high temperature, and the cake is dissolved in water. The Ir salt is precipitated by addition of NH4Cl and treated with aqua regia. Reducing this solution in volume will give you IrCl3.xH2O

Overview of possibilities:




Reference: PB Kettler. Platinum Group Metals in Catalysis: Fabrication of Catalysts and Catalyst Precursors. Org Proc Res Dev 7 (2003) 342-354


I agree there are easier precious metals to start playing with :D For sources, it might be possible to check out specialized gold and silver dealers. They also sell platina and palladium, and may have access to iridium, rhodium and ruthenium. These metals are used in the electronics industry as well, and you can find companies specialized in recuperation of the precious metals from old electronic equipment. Drawback is you often have to order no less than 1 kg, but if you have a chemical company, this clearly is the way to walk.
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[*] posted on 14-1-2006 at 12:40


@ woelen:
Hollemann- Wiberg states that the best solvent for Iridium is a hot mixture of conc. HCl and NaClO3.

Iridium begins to oxidise in air at 700°C forming volatile IrO3.
For working with hot iridium, inert gas atmosphere or vacuum must therefore be used.
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[*] posted on 14-1-2006 at 14:22


The price I quoted is around one year old. Indeed, prices of the precious metals fluctuate wildly, but I think that the price of iridium still will be something like that.

With the ruthenium I have, I also tried the method conc. HCl + NaClO3. Someone on usenet:sci.chem told me, but it did not work at all, despite the stories about ruthenium reacting violently or almost explosively with HCl/NaClO3. I got a lot of ClO2 and some Cl2, so indeed I could get explosions :D, but still completely undissolved Ru metal. I suspect that this method also does not work with iridium.

Someone else on usenet:sci.chem (Farooq) told me to use an alkaline solution of NaClO and boil the solution with the ruthenium powder in it. That worked like a charm. Within minutes, the powder was dissolved. However, this method does not work with iridium as stated by multiple people on other forums (e.g. the dutch chemieforum).

[Edited on 14-1-06 by woelen]




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[*] posted on 14-1-2006 at 17:27


Johnson Matthey is used by a number of U.S. jewelers for many precious metals, including iridium. They sell Ir in sheets, disks, wire, crucibles, and other forms:
http://www.noble.matthey.com/product/detail.asp?article=34

Their catalyst division also sells a large number of compounds of the noble metals, including most of the ones mentioned in this thread:
http://www.jmcatalysts.com/pct/marketshome.asp?marketid=79

I couldn't find any prices, though, you'd have to contact them. Ironic as it sounds, maybe a jewelry supplier might have better prices...?

Z
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[*] posted on 14-1-2006 at 23:37


Woelen can you post the source you have for the powdered iridium?
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[*] posted on 15-1-2006 at 06:21


An eBay seller, who had iridium and ruthenium powder, is known as [removed on request] on eBay. From him I purchased 5 grams ruthenium metal for EUR 30. He is Germany-based. His email address is [removed on request]. This person had iridium metal in the form of fine powder as well, but I did not purchase that, because I did not know of any way to dissolve this (see previous post). This was in april 2005.

Another interesting seller was [removed on request]
I purchased 10 grams powdered rhenium metal metal from this seller one year ago. He also had iridium at that time.
This seller also is known from eBay as "smart-elements". Sometimes he has interesting things on eBay, other times nothing or just very expensive things. Just check out.
This seller is Austria-based and he also apears to have a place in Germany, so he is most interesting for European persons.

[Edited on 3-12-07 by woelen]




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[*] posted on 15-1-2006 at 09:22


C.W. Ammen in his book Recovery and Refining of Precious Metals describes dissolving platinum, Pd, and Ir using aqua regia.



The single most important condition for a successful synthesis is good mixing - Nicodem
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[*] posted on 15-1-2006 at 11:48


I have read that book front to back many times Magpie, but there exists abundant typographical errors (like any other Ammen book, good hands on experience, but bad editing :p) so I wouldn't put too much emphasis on that procedure when later on he talks about fusing it with potassium hydroxide and nitrate in zirconium crucible and then dissolving the fusion in water leaving IrO2 as a powder which is then dissolved in aqua regia and precipitated with ammonium chloride. IIRC, iridium is the most corrosion resistant pure metal known to man.

Neutrino, I personally would call Johnson Matthey or Alfa Aesar (a subsidiary of the former) and inquire about it, $200/troy ounce sounds a little low to me but I imagine it would be in that ballpark. You can buy off of ebay, but you'll pay probably the same or more and you won't have a guarantee about purity. Cheapest thing would be to get a powder, and definitely easiest when it comes to dissolving it.

Oh, eclectic, I have no idea how you plan to fabricate yourself a ring out of it using an arc furnace but I'm interested in hearing your idea nonetheless. I'm thinking you'll have to use an e-beam furnace to keep it molten (since at those temperatures removing the heat source=instantaneous solidification b/c of loss to radiation) and the mold hot enough to prevent instant chilling. Additionally, what type of mold would you use? I'm guessing sintered magnesia since graphite and SiC are out of the question because you'll get iridium carbide. Anyways, U2U me, I'd like to discuss it :)

garage chemist, this statement "Iridium begins to oxidise in air at 700°C forming volatile IrO3.
For working with hot iridium, inert gas atmosphere or vacuum must therefore be used." goes against the information found (courtesy Johnson Matthey) here: http://www.noble.matthey.com/product/detail.asp?article=34

I always thought iridium behaved more like the oxidation-resistant platinum than osmium and ruthenium (which both form volatile, poisonous oxides, some @ room temperature).


And from the conflicting reports of what dissolves it and what doesn't (and the limited number of us that actually have any and aren't just speculating) it would seem that the jury is out on what works best in an aqueous environment.
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[*] posted on 16-1-2006 at 08:05


I asked Matthey, they said they don't deal with individuals. Alfa is a chemical supplier, I don't see any point in asking them. I'll try woelen's suppliers next.
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[*] posted on 17-1-2006 at 16:47


I went ahead and looked through the Alfa catalog in the lab and yeah, you definitely don't want to order from them, the minimum purity Ir is about 1.7X the market value. Maybe try advent research materials or perhaps even READE: http://www.reade.com/Products/Elements/iridium.html

but I suggest you talk eclectic since he had to purchase 5 ounces of it, I'm sure he knows where to buy it (and the price he got sounds pretty fair!)
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[*] posted on 17-1-2006 at 17:39


1.7 times the spot price? Are you sure about that? The quote I got was much more. I will have to look into this because this is the best deal I have heard about so far.

Buying in bulk at the spot price is easy. I'm trying to <b>avoid</b> spending thousands...

Is there any particular reason you advise on those companies? Their kind usually doesn't sell to the likes of us.
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