Osmium, Iridium and dealing with toxics

I have some concentrate bound in SiO2 slag, thats not really the point here because I have a smallish sample that has been ultrasonically pulverised to almost a dust consistency so I'm hoping most of the cash is not bound in glass.

I have read up on just about every source I could find about refining using acid. My plan is to dissolve out the non pgm's with sulfuric and later nitric acids in a two step wash to hopefully make collecting the silver easier. Then hit the PGM's and gold with AR and selectively pull out the gold with SO2 the Pt with NH4Cl.

I have a small issue with the iridium, I just don't know if it will dissolve or not. It's 20.4% of my precious metal content. I will have a decent amount of SiO2 left so I can't just assume the andy remainder is iridium. If I get the go ahead to go full scale with the recovery I could use HF to wash the SiO2 out but at that point I could afford to hire a real chemist to help me. I may try to cook the crap out of it with AR or try to use density to separate it (panning or iridium anyone).

On to the real question, I'm not finding much on osmium refining. I know this stuff is hella toxic and I have it in powder form that loves to turn into OsO4 great (-_-') I'm not a real chemist but I know it's supposed to be resistant to AR but I don't know when or how to kick it out of solution or if it will wash away as OsO4 with my early steps. It represents 13.4% of my precious metals. OsO4 melts at 40°c and boils at 130 so perhaps I should try to convert any elemental Os to OsO4 and distill it as a first step before I wash the non platinums out and later convert it to a metallic state.

My non precious has 1% Pb, pritty sure I know how to kick that out of solution and I can sell it but it also has 1% As and I dont know how to kick that out or what to do with it once it's isolated. If I was smart enough perhaps I could make technical grade arsenic sulfides and sell them.

Sorry I drone on too much I really should learn to keep my questions few and simple.

It seems to me you have an ore concentrate which while containing values also has some very toxic elements in its makeup. Before any treatment I would fully check out any risks to you or anyone else and be prepared to contain such hazards and keep everyone safe. Many ores simply aren't a backyard proposition and I'd advise taking some professional help and advice before you do yourself or anyone else some harm. You don't sound a complete novice so I'm hoping you understand my concerns and while the osmium may have some value it's not widely used in industry so spending time and money to refine it may be a no go. Lou is our resident expert on PGMs so his view would be well worth having on this whole topic and I would follow any advice he cares to give.

I'd advise forgetting about the whole thing. You're not working with something easy to work with, and really, given the materials, if you have to ask how to do it, you should not be doing it.

Hate to be a downer, but it's only (potentially) money--money that you might not enjoy if it sends you or worse yet, others to an early grave.

Save yourself a million dollars in frustration and stop with it.

OsO₄ or osmium tetroxide is REALLY DANGEROUS! Yeah, I'm yelling, sometimes it's motivated.

OsO₄ might have a melting point at 40°C but before that it sublimates , ie turn into gas. It is so volatile that it is delivered in glass ampoules that have been melted together. One major usage is in staining samples for electron microscope. The ampoule is broken inside a fume hood and just put beside the sample, the vapors is enough to do the job.
One of the major organs that OsO₄ attacks is the eye, depositing osmium metal in the cornea, you lose your sight from metal that is covering your eyes! And if that isn't enough it can kill you if you inhale it even at a level that you don't smell it.

If you haven't realized it yet, one of the most scary chemicals I know of is osmium tetroxide.
http://en.wikipedia.org/wiki/Osmium_tetroxide#Safety_considerations

That arsenic you have is child's play in comparison.

Göran

Yah it's bad but it's not the worst, I'm far more afraid of plutonium, polonium and HF but what scares me the most is Dimethylmercury I wouldn't touch that stuff if my life depended on it. OsO4 definitely bad stuff probably worse than hydrazine. I have a fume hood, face shield, pvc gloves, pvc apron and was considering a tyvek suit but I will add a respirator and goggles. I take safety seriously which is part of the reason I did not want to mess with HF just yet.

if you have to ask how to do it, you should not be doing it.

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Don't really agree with that attitude, askling is one of the fastest ways to learn. Should or should not I'm going to try my best. I wish I had a glove box but I think I can be adequately safe with what I already have.

I just don't know whether it's better to reduce it early on and process it with the rest of the AR (and would it stay reduced?) or intentionally oxidized it and process it out first. Or perhaps there is a superior method I am unaware of. I may like to forget about it but it is a major enough constituent that it must addressed somehow.

Yes Göran I have read the wiki and other documents regarding it, I found osha's page on it most useful.
http://www.cdc.gov/niosh/docs/81-123/pdfs/0473.pdf

Adaptation,

Since you've been here for less than half a day, I understand you don't yet know the people who have posted in response to your questions. I can't say I really know Göran's professional background, but he is very knowledgeable. nickvc spent many years as a professional refiner working for Johnson Matthey. Lou currently makes his living as a professional refiner specializing in the platinum metal group. If these men say you should forget about it, I would recommend following their advice.

Adaptation said:

Lou said:

if you have to ask how to do it, you should not be doing it.

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Don't really agree with that attitude, askling is one of the fastest ways to learn.

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That only works if you follow the advice you're given. In this particular case, Lou is right. This isn't something you should be learning how to do from bits and pieces you read on the internet.

This forum is seven years old. There are nearly 200,000 posts on over 18,000 topics. There is a reason you won't find any information here about what you're proposing to do. If you have enough of this material to make it financially worthwhile, then you have enough of it to send it to a professional refiner.

Dave

Dave I did work for JM but my refining was all done with my own company and similar to Harold I learnt from scratch but without that wonderful book Hoke, I'm sure I lost some values by not having a full understanding but hey I made money from my endeavours.
I have learnt more here perhaps than in my time professionally refining certainly enough to spot things to avoid and definitely whose words you can count on as been as the final ones, with that comment in mind,as I previously said Lou will know the answers to the OPs questions and if it were me personally I certainly would take serious notice of his comments and advice, even if they were not what I wanted to hear.
Seriously Adaptation listen to Lou even if you don't listen to me, I know it sounds like we are killjoys but the reason is this material is seriously hard to recover let alone refine and with its toxicity problems it could do some serious damage if not processed correctly. This material is maybe fine for multi million dollar set ups with the correct emission controls and professional chemists but not in your back yard with a few buckets and beakers.

Nick,

Thanks for the clarification. I didn't know the exact details of your professional refining career, but I knew you had mentioned spending some time with JM.

Dave

Well I guess what I will do is wash it in hot water a few times to start with and assume whatever is left is in metallic form and will come out the other pgm's at some point.

Why don't you get a small sample, contact a reputable company that does such things, send it to them, work out terms, and save yourself a lot of trouble?

I will not give any suggestion on how other to do it than to contact a business that has the proper systems in place to manage the material.

Given the rarity of Os/Ir, there's more than a 99.9999% chance that what you have doesn't have those elements in significant enough amounts to even be valuable. You throw percentages out there, but how do you really know? Do you have a copy of the assay report? If so, how was it done?

Slow down.

The assay was performed by total acid digestion followed by icp spectroscopy. It was performed on a few chunks of from a large pile which may not be homogenous. The values from the assay represent more than 3% of the total with Pt representing 35% of that. Very rich stuff and there is quite a bit of it. I looked into Johnson Matthey but for a number of personal reasons I don't wish to go that rout. I plan on doing a small scale operation to bootstrap a large scale one in the near future.

If one of the reasons was cost then I think that gives you another pointer to the difficulty of processing your ore, I'm sure they would be using the best available equipment with all the necessary environmental controls to process this material, another possibility for refining this may be Inco who are specialist PGM refiners but I expect turnaround times may well be months.
Please be very cautious if your going to try this, I still think your wrong and personally I wouldn't waste the time or take the risks involved especially after Lou said exactly that.

Adaptation said:

The values from the assay represent more than 3% of the total with Pt representing 35% of that.

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And that doesn't send up a red flag for you?
I'm going to play the devil's advocate for a moment.
You just told me that you have an ore that contains 306 ounces/ton platinum.

Platinum is considered to be 1/10 as common as gold. To my knowledge, it isn't found in large percentages, with rare exception. And you happen to have over 300 ounces/ton?

What does a fire assay show?

If I've misunderstood what you've said, please correct me.

Harold

I did not say it was raw ore.

Adaptation said:

I did not say it was raw ore.

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I stand corrected, and you have my apology.
Now, what does a fire assay show?

Harold

So, is what you have slag from a smelting operation?
And, there was no fire assay, right?

FrugalRefiner said:

I can't say I really know Göran's professional background, but he is very knowledgeable.

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Thanks Dave!

I have a Master of Science degree in physics but read a lot of extra math, computer science and some chemistry, worked as an army telecom engineer and also with helicopters, I've run my own computer and electronics consultancy for a couple of years. Then ten years as a research engineer on the university and now I'm working for a small company that develops and sells measurement systems, doing all different things from electronic design to climbing 100 meter masts during service jobs.
Refining is a hobby just as the two electron microscopes I have, one SEM (450 kg) and one TEM (1800 kg). That way I've been introduced to osmium tetroxide as it is used as a stain for biological samples in electron microscopy. Other hobbies I have is mineral collection, coin collection and I'm collecting old computers.
... oh, and I love scrapping stuff.

Try to put a label on that! :mrgreen:

/Göran

g_axelsson said:

Try to put a label on that! :mrgreen:

/Göran

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No problem. You're a renaissance man like many on this forum. 8)

Dave

FrugalRefiner said:

g_axelsson said:

Try to put a label on that! :mrgreen:

/Göran

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No problem. You're a renaissance man like many on this forum. 8)

Dave

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You got me there, that is in fact how I sometimes think of my self!
Probably why I like this forum so much.

8)

Göran

I can tell you from experience that there are false readings of high amounts of iridium when there is sio2 present. Also, bismuth reads iridium on xrf if it isnt specifically calibrated for it. Also, if your sample is from a smelting operation and is not homogenous there is no reason to do anything until you have a proper assay. If Lou is telling you to forget it then forget it. I know he is very skilled and not to sound like one of his groupies but Im sure he could refine that material himself and if you can get that much pgm from that material why wouldnt you have a large refinery run it for you or ask someone on this forum to.do it or recommend someone. Anyway, I wish you well and if everything turns out good, you might be the next millionaire/billionaire, goodluck. Just remember, I could always use a donation if everything pans out!!!!!