# Which precious metal would you like to see refined?



## Lou (Oct 1, 2012)

I would like to take suggestions on which metal we should get to know better. There is limited info on Pt, Rh, Ru/Os and some others...


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## NobleMetalWorks (Oct 1, 2012)

Rh is a total unknown to me, I can readily work Pt and Pd but don't even have equipment for Rh, I would have chosen Os next.

Scott


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## Oz (Oct 2, 2012)

We have much on the forum about silver and gold, and it would be tempting to talk about ruthenium, osmium, or iridium. But out of the platinum groups those three are not encountered as often as Pd, Pt, and Rh. Most that wish to try refining platinum groups will try with catalytic converters due to easy access. We have far more written here on platinum and palladium than we do rhodium. Rh is also increasingly being used as a plating (hence a valuable byproduct) on sterling and karat gold scrap. 

Rhodium has my vote.


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## acpeacemaker (Oct 2, 2012)

I don't see a slot for 80's hair bands. :lol: Just kidding
Rh for me as well

-Andrew


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## Palladium (Oct 2, 2012)

Pd i would like to learn about more. Lou what about the thread on nucleation? I'm still learning about it and would love to hear your wisdom on the subject.


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## Sucho (Oct 2, 2012)

Lou!
you have a lot of free time :lol: 

i would like to see separation of a sinthered mixture of light and heavy platinum metals.

it can be a great model, because there will be visible partial dissolutions, "contaminations" with other PGM, dragdowns, coprecipitations etc etc.

mixed PGM stuff is most common input material 

but i know, this is a looot of work


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## Lou (Oct 2, 2012)

Most of what we see here on Pt is just making ammonium hexachloroplatinate. Not that one can't get decent results (or more than decent, bordering on unexpectedly impressive if you're Steve) with simple re-precipitation.

Maybe I will do Pt, Pd, Rh.

Most often my feed is PtRh or PtIr and the Pd is with Au, Ag. I'd really rather not get terribly involved with Ir because I don't have enough at the moment to make it worth the hassle (usually get it from jewelry).


Let's see how it pans out.


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## Oz (Oct 2, 2012)

Lou said:


> Maybe I will do Pt, Pd, Rh.


That is the most common mix PGM is found in.


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## Lou (Oct 2, 2012)

Palladium said:


> Pd i would like to learn about more. Lou what about the thread on nucleation? I'm still learning about it and would love to hear your wisdom on the subject.




I'll hit it soon.


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## Geo (Oct 2, 2012)

i would like to begin experimenting with Palladium myself. i have at least a thousand pounds of material that contains MLCC's. by most of our refiners standards, this isnt very impressive. but for me, its a nice size nest egg if i can learn how to process it efficiently.


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## Lou (Oct 2, 2012)

Looks like palladium is staging a come back on rhodium!


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## gold4mike (Oct 2, 2012)

Palladium for me too. I have a lot of MLCC's I've been saving and hope that they contain some palladium.


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## Emmjae (Oct 2, 2012)

Palladium has my vote too. That's what I would like to experiment and learn next.


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## Harold_V (Oct 3, 2012)

The harsh reality is that the average refiner who deals with the platinum metals is most likely to encounter platinum and palladium, possibly exclusively. The vast majority of readers will benefit far greater by discussing these two metals, as the others aren't likely to be encountered, especially in quantity. These comments are particularly true for those who process karat gold from jeweler's wastes and dental wastes. 

Harold


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## hfywc (Oct 3, 2012)

since i deal with electronic stuffs i chose palladium however i would like to see how you would separate pgms in the future if that is not too much to ask of youb:wink: 

alan


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## Lou (Oct 8, 2012)

Palladium it is.


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## rewalston (Oct 9, 2012)

Lou said:


> Palladium it is.



Lou, be gentle with him so that it doesn't hurt to much :lol: 

Rusty


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## kurt (Oct 9, 2012)

I have been very busy lately in fact so busy I haven't even had much time to log on & read the forum so I missed this poll.

That said - had I read the poll before it closed I would have voted for Rh due to the fact of the three PGMs most incountered (Pt, Pd & Rh) Rh has the least info to be found

Kurt


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## g_axelsson (Nov 28, 2016)

I demand a recount! :mrgreen: 

I voted for rhodium but I can accept a palladium thread by Lou too... still waiting.  

Göran


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## Palladium (Nov 28, 2016)

It's according to if we're going by the popular vote or the electoral college. :mrgreen:


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## justinhcase (Nov 28, 2016)

Dang ,The place became a democracy and I missed it.
Rh would be helpful as it is the one left over after every thing else has been put into solution.
Though Pd an Pt are more common they are not that hard to pull out of your system,(silver cell or A.R) 
I do come across Rh on silver items and some high end settings,I can detect it but little else. :lol:


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## kurtak (Nov 29, 2016)

g_axelsson said:


> I demand a recount! :mrgreen:
> 
> I voted for rhodium but I can accept a palladium thread by Lou too... still waiting.
> 
> Göran



:lol: :lol: :lol: 



> It's according to if we're going by the popular vote or the electoral college. :mrgreen:



Doesn't matter because ether way the system is ether rigged - OR - it was hacked :twisted: 

Kurt


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## Lou (Nov 29, 2016)

Palladium it is.

Any particular way? Classical? Bromination? Solvent extraction (that'd be boring, but a time lapse is always cool)? Ion exchange resin?

I wonder if I can just break it up into photos or videos?

Lou


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## g_axelsson (Nov 29, 2016)

There are a number of threads and youtube videos showing how to do it for the home refiner. So I would like to see how it is done professionally. Or at least a quick overview to get a starting point to dig into the subject.

If solvent extraction is the way the large refineries is doing it today then it would be interesting to know which steps are involved at least.

One think about palladium refining I have wondered about is if there are any tricky situations to avoid where you easily lose your palladium as a complex. Is there a fool proof way of getting all palladium in solution?
I have a vague memory of palladium and silver could form a complex but I can't find that post again.

Reading my post I realize there are quite a lot about palladium that I don't know yet. This will be a great thread!  

Göran


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## FrugalRefiner (Nov 29, 2016)

I'd also like to hear about safety. We often warn about the dangers of PGM salts. As I understand it, Pt(IV) is the worst, but I'd like to know how hazardous Pd is in various forms in the various processes you've mentioned. Is one safer than others? Would members be best advised to cement, precipitate as chloride salts, or...? Pros and cons of the various methods would be nice. Just some thoughts.

Dave


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## Lou (Nov 29, 2016)

So far as I know, it is Pt(IV) that causes histamine release and is allergenic. Most of the other PGMs are handled in such small quantities and with such care (Ru, Os) that their long term chronic effects are very poorly understood, if they even have effects.


The usefulness of alkyl sulfides is that they do not extract platinum with the Pd BUT they like gold and silver, A LOT! It is very simple to stir for an hour (or more depending on the sulfide and its level of steric hindrance) a Pd solution and extract to less than 20 ppm Pd; wash this solvent with dilute HCl to deal with the entrainment, and then strip quantitatively with ammonia to the tetrammine complex. That can be reduced directly or acidified to give the well familiar yellow diammine palladium (II) chloride. 

If that's what you wish to see, so be it.


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## autumnwillow (Dec 7, 2016)

Rh please!


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## rickbb (Dec 7, 2016)

Since I've only gotten comfortable with gold and silver I'll vote for Pallidum as it's the most likely the one I'll encounter in e-scrap. And probably have been tossing out with the waste.


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## Topher_osAUrus (Dec 7, 2016)

Well, the poll ended in 2012?

But, if we are still casting out votes here. Id go with iridium.


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## autumnwillow (Dec 7, 2016)

Well then that's four years. So let's pick four for Lou to write up. Rh Pt Pd and Ir. :lol:


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## Topher_osAUrus (Dec 7, 2016)

autumnwillow said:


> Well then that's four years. So let's pick four for Lou to write up. Rh Pt Pd and Ir. :lol:



Hehe. 
Those all sound good. Can we just throw Os on to that shortlist too? ..Or should we just kindly ask Lou to cover platinum and all her temperamental sisters?


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## 4metals (Dec 7, 2016)

Well maybe not precious but......

Since a lot of our members are recycling e-waste, maybe a discussion on which rare earth metals are commonly found in e-waste to either simplify collection and possibly lead to refining. I'm sure if the components with higher concentrations of these elements can be isolated they will fetch higher prices even without refining.


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## Lou (Dec 7, 2016)

Hey guys, in case y'all didn't figure it out, I do this for a living and I don't really want to get crap-canned for giving away some secrets. I do get to actually process Ir, Rh, Ru, Os, Ag, Au, Pd, and of course, Pt to various levels of purity, from just lots that go to 995 to special inquiries that go to a lot of nines and require all sorts of approaches (like zone refining, for instance. That's the way to clean up Ir!). 

I'll stick to demonstrating what's in the literature for educational purposes, not necessarily the finer details of how we do things. Also keep in mind that the whole point of refining is to do the same mindless tedium over and over again to get the same result. To do that requires taking a diverse array of feedstock materials and getting them to fit into the refining black box (or flow sheet as we call it). 

That's a perfect world--in reality, I get the great challenge processing different feeds with odd and bizarre combinations of elements which make refining very difficult for traditional refiners. A good example is molybdenum and platinum. Both dissolve in aqua regia, both resist hydrolysis and both form sulfides. So what's a poor chemist to do aside from multiple re-precipitations as a chloroplatinate? In some cases, it's more expedient to take the discount and make it some other refiner's problem where they don't necessary chemically separate it, they just dilute the heck out of the problem metal with more platinum. In this case, we're fortunate because molybdenum can be removed by roasting in air and off it goes as MoO3. Great in theory, but it's hard to get at that molybdenum when it's surrounded by platinum metal. Now it goes from a chemical issue to a surface area: volume physical problem. 

Simply put, refining is really taking as many impurities away from your target metal as possible, or selectively taking your as much of your target metal away from all the impurities. Doing that involves a lot of picking and choosing because yield is as important as quality. It's a constant battle for the cake and the ice cream!

In this case, we're going to demonstrate palladium refining with solvent extraction and let's start before the photos with the theory of the whole process. 

Look for a post in Techniques.


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## Topher_osAUrus (Dec 7, 2016)

Thank you Lou.

I surely don't want you to get the boot for giving away proprietary secrets of your work, and I'm sure nobody else wants that either.

We are very fortunate to have you here at this great forum, and I will eagerly await your post.

You had mentioned once before,that over at sciencemadness forums, there was a thread going over the purification of platinum and palladium (amongst others I believe), so I have been scouring the forum (sciencemadness) to find them. That too, is a great place with a LOT of knowledgeable people. So, thank you for sharing that as well.


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## Lou (Dec 7, 2016)

Topher_osAUrus said:


> autumnwillow said:
> 
> 
> > Well then that's four years. So let's pick four for Lou to write up. Rh Pt Pd and Ir. :lol:
> ...




Glad to do them all. I want a kilo contained of each to start with 


To be honest though, I don't think showing the distillation of Os (or Ru) is really appropriate. I mean it's easy, so easy. It's also so easy to get killed. 

Ir is also ridiculously boring. If it's bulk pieces, it's basically boil the **** out of it in aqua regia and hydrofluoric acid. Fun. Then, depending on what's in it, the great pleasure of either pulverising it and mixing it with diluent metal and digesting that away or else sending it off to someone to electron beam remelt it and clean it up that way.

I wish I could put into words just how flipping corrosion resistant iridium is. I mean, even with stuff that corrodes it, it's not fast unless it's a super fine powder, and that's best with salt and chlorine, just like rhodium chlorination, which I already showed y'all.


EDIT:

Toph,

actually people do want me to do demonstrate that. It's how people make money--knowledge (well and opportunity). 

That thread on sciencemadness was by me. 

https://www.sciencemadness.org/whisper/viewthread.php?tid=9721#pid113781


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## Topher_osAUrus (Dec 7, 2016)

Thank you Lou!

The amount of technical and practical knowledge you have (and so kindly bestow upon us) is truly staggering.

Iridium is just plain fascinating. 
...but, thats not to say the other precious metals aren't
Each one has it's own little idiosyncrasies and nuances, and their own personality it seems.

Again, thank you for sharing your wisdom. (and the link!)


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## Lou (Sep 24, 2019)

Wow forum, 

I suck at following up here. For those who didn't know, I was in a car accident the next month and ended up having some issues with the ol' noggin. I did find the semblance of a palladium refining draft in my drafts page so in fairness to myself, I did start working on it.

Let's revisit this palladium thread.

How would people like to see the palladium refined?

If from chloride, it will be with solvent extraction using n-dodecylmethylsulfide, which like similar compounds, dioctylsulfide and n-dihexylsulfide is an alkylsulfide with a high affinity for both palladium, gold and silver. It is perhaps the premier way to separate Rh, Pt, and Ir from post distillation, post sulfite, post silver chloride refinery liquors. 

If from nitrate, it will be via precipitation of an insoluble salt.


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## Lou (Sep 24, 2019)

4metals said:


> Well maybe not precious but......
> 
> Since a lot of our members are recycling e-waste, maybe a discussion on which rare earth metals are commonly found in e-waste to either simplify collection and possibly lead to refining. I'm sure if the components with higher concentrations of these elements can be isolated they will fetch higher prices even without refining.





Many of those rare earth metals, the lanthanides, can be scavenged by either fluoride or oxalate precipitation chemistry. The latter is important to realize because any of the lanthanides can contaminate gold in certain circumstances.


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## Shark (Sep 24, 2019)

Lou said:


> Wow forum,
> 
> I suck at following up here. For those who didn't know, I was in a car accident the next month and ended up having some issues with the ol' noggin. I did find the semblance of a palladium refining draft in my drafts page so in fairness to myself, I did start working on it.
> 
> ...



I am not sure how to word it without sounding to simple, but I would I like to see the easiest method using the easier to find chemicals. Here I can show my ignorance of the subject and say that the nitrate method sounds like the easier route based on the simple method. But either way will work for me as I know basically nothing of refining Pd.


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## g_axelsson (Sep 24, 2019)

I've been waiting for the continuation of this thread, but I know that you are quite busy so I didn't want to nag you about it....
... and I'm as bad as you on following up on many of my own threads. :lol: 

Personally I'm fine with any method, but I rather see a method used to discuss palladium refining that hasn't been discussed on the forum before. There are several good posts about palladium, here are some of my references.

[1] Lazersteve : http://goldrefiningforum.com/phpBB3/viewtopic.php?f=51&t=8657 Purifying Palladium Precipitated from Dirty Solutions.
[2] Lou : http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=20710&start=40#p223779 Separating palladium from silver in a nitrate solution.
[3] Many good posts : http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=5822 Precipitant for palladium.
[4] Kadriver : http://goldrefiningforum.com/phpBB3/viewtopic.php?f=51&t=18907 Ammonia Soluble Hexachloropalladates (IV).
[5] Thread with many posts by Freechemist : http://goldrefiningforum.com/phpBB3/viewtopic.php?f=51&t=9058 Palladium from nitrate solution.
[6] Freechemist : http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=51&t=11078#p108471 Several ethods to reduce diammine-palladium(II)chloride (yellow palladium salt) to the metal.
[7] 4metals : http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=51&t=6638&start=20#p72403 This procedure will clean up Palladium which have been collected as salt and reduced.
[8] 9kuuby9 : http://goldrefiningforum.com/phpBB3/viewtopic.php?f=51&t=19352 Refining Palladium concentrates following the method 4metals described.
Hoke is describing basically the same method on page 177. http://goldrefiningwiki.com/mediawiki/index.php/Hoke:Refining-Page-177

Göran


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