# Inquart mixed PGM's?



## Geo (Apr 10, 2022)

I have managed to produce metal with Pt, Pd and Rh by smelting filter ash. I am wondering if it is feasible to inquart this metal with silver and leach in nitric acid as you would with karat gold. It would digest the silver and palladium leaving only Pt and Rh. It is much easier for me to get a 2-way assay than a 3-way assay. I have found a reputable refiner that will accept relatively small amounts of a couple of ounces at a time. Is this something that can be done or is there a chance of dissolving Pt or Rh with just nitric acid?


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## orvi (Apr 10, 2022)

Geo said:


> I have managed to produce metal with Pt, Pd and Rh by smelting filter ash. I am wondering if it is feasible to inquart this metal with silver and leach in nitric acid as you would with karat gold. It would digest the silver and palladium leaving only Pt and Rh. It is much easier for me to get a 2-way assay than a 3-way assay. I have found a reputable refiner that will accept relatively small amounts of a couple of ounces at a time. Is this something that can be done or is there a chance of dissolving Pt or Rh with just nitric acid?


When I worked with PGMs, we have done experiments, when we alloyed PtRh in copper and aluminium, 20% PGMs concentration, 87:13 Pt:Rh ratio. When dissolving copper PGM alloy in nitric, we observed good ammount of Pt going to the solution. When dissolving alloys in nitric, there is always some Pt dissolved to the liquid, but not all of it. Rhodium required few days boiling in nitric (65%) to appear on XRF, leached into the solution very very slowly.

Inquarting with silver would work, but I cannot say what PGM content would be OK in terms of working temperatures. PGMs quite sharply raise the melting point of the alloy. 

Alternatively, dissolve everything to the HCl/Cl2 and selectively precipitate Pd with DMG, if it isn´t too much of the material.


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## Geo (Apr 11, 2022)

orvi said:


> When I worked with PGMs, we have done experiments, when we alloyed PtRh in copper and aluminium, 20% PGMs concentration, 87:13 Pt:Rh ratio. When dissolving copper PGM alloy in nitric, we observed good ammount of Pt going to the solution. When dissolving alloys in nitric, there is always some Pt dissolved to the liquid, but not all of it. Rhodium required few days boiling in nitric (65%) to appear on XRF, leached into the solution very very slowly.
> 
> Inquarting with silver would work, but I cannot say what PGM content would be OK in terms of working temperatures. PGMs quite sharply raise the melting point of the alloy.
> 
> Alternatively, dissolve everything to the HCl/Cl2 and selectively precipitate Pd with DMG, if it isn´t too much of the material.


Thank you.  
I'm sorry. I meant to say, add silver during the first smelt. My idea was to use cemented silver that is very nearly a powder as is. Just add the silver to the ash and flux and mill it all together. It can act as a collector metal and then leach the bead in nitric acid. I haven't tried yet. I was hoping someone has already tried and can give some insight on what they achieved. I haven't smelted the material the first time yet, only a few samples.


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## orvi (Apr 11, 2022)

OK, that is bit new idea to me.
But all in all, why not. I will give it a try, it sounds like a good idea. If I am not missing some obvious things and problems 
In the similar fashion as litharge smelting, I think you should be able to add like powdered silver oxide and it should be similar in action. But why not cement silver instead, clever  
I would go for a test run, for sure.


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## samuel-a (Apr 11, 2022)

Jeff,
Do you have an Rh assay for the initial ash material?
I would concern with the collection efficiency of Rh.


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## nickvc (Apr 11, 2022)

Geoff with enough silver PGMs will dissolve with nitric which you can then use HCl to form silver chloride to filter off then cement the PGMs on copper then dissolve any Pd using dilute nitric which you can cement out , that should leave you with the Pt and Rh and I’m thinking that as Rh is very un reactive you may be able to separate by dissolving the Pt in AR leaving the Rh behind, none of the above may produce perfectly clean separate elements so further refining may be necessary depending on your needs.


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## kurtak (Apr 11, 2022)

Geo said:


> I have managed to produce metal with Pt, Pd and Rh by smelting filter ash. I am wondering if it is feasible to inquart this metal with silver


Geo - concerning the Rh Sam has a valid point --- Sam posted ------



samuel-a said:


> Do you have an Rh assay for the initial ash material?
> I would concern with the collection efficiency of Rh.


Here is a discussion wherein Lou made me aware of this back in 2016









Buttons and Bars


Come on guys, post some pics. Us newbies need more motivation. In between reading Ms. Hokes book and others we need a break. Something to look forward to. Granted we are not going to rush thru the process and get complacent with safety. That goes without saying. Personally I love seeing...




goldrefiningforum.com





I did have "some" gold in that smelt & I did recover "some" Rh when I processed the cones --- the question is - was it enough gold to actually get "good" recovery of the Rh - or did I suffer loses & if so how much loss - I will never know because like you the Rh was in filters so no idea how much Rh was in the filter ash to start with

Concerning the Pt - Yes - When alloyed with silver at least some Pt will go into solution with nitric - how much depends on the ratio of Pt to Ag

So - I guess the bottom line I am getting to is that you may be better served using gold as your collector metal - then go to AR which will dissolve Au/Pd/Pt (& likely "some" Rh) but leave most of the Rh behind (somewhat dependent on alloy percentages/ratio)

Then drop your gold with copperas - then drop the Pd with DMG (or other precipitant "selective" for Pd) then your Pt (ether with selective precipitant or cementing)

OR - after dropping gold with copperas - cement the Pd/Pt - then use nitric to dissolve the Pd from the Pd/Pt cement - then (again) cement the Pd from the nitric

To be clear - none of this is perfect - the separation/refinement of PGMs (especially when mixed) is a difficult task at best - due to their close relationship to each other they tend to follow each other (to some degree) so generally need to go through re-refining steps to get true separation

Which is why (unless already pure) they pay less for PGMs &/or why assays cost more

THEN - if there is also (already) silver in those filters - it adds another complication (to the above) depending on the amount of silver - IF - after smelting/alloying Au/Pd/Pt/Rh & there is only trace amounts of silver it's not a big problem - however IF the silver is to high in the alloy then the AR will have a hard time due to AgCl crusting on the surface during the dissolve

Bottom line - gold &/or (other) PGMs need to be high enough to prevent loosing Rh in the smelt

OR - if you have enough of these filters you "may" be better served to just send them in - take the hit on the payout AND the added cost of higher assay fees

As we know - working with PGM salts is a VERY toxic process - even if you know/understand the process & take proper precautions !!!

As you know - we have lost a few members to the refining of PGMs - *that knew what they were doing* !!! 

For what it is worth

Kurt


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## snoman701 (Apr 11, 2022)

how much ash are we talking about?


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## Geo (Apr 11, 2022)

samuel-a said:


> Jeff,
> Do you have an Rh assay for the initial ash material?
> I would concern with the collection efficiency of Rh.


I sell to Elemetal Direct. I know the hard feelings some have towards the company but they have always been good to me. The associate that I deal will will assay a couple of samples for me every time I go in. He can't print a report as it only prints an invoice on sales but he lets me stand with him to read it for myself. The two samples I took was from different locations in the container. The first sample had 1.48% Rh along with all the various other metals you would expect. The other sample was 1.89% Rh. I have 9.6 pounds of milled and screened ash.


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## Lino1406 (Apr 11, 2022)

Literature says. Rh will not dissolve in silver


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## orvi (Apr 12, 2022)

Geo said:


> I sell to Elemetal Direct. I know the hard feelings some have towards the company but they have always been good to me. The associate that I deal will will assay a couple of samples for me every time I go in. He can't print a report as it only prints an invoice on sales but he lets me stand with him to read it for myself. The two samples I took was from different locations in the container. The first sample had 1.48% Rh along with all the various other metals you would expect. The other sample was 1.89% Rh. I have 9.6 pounds of milled and screened ash.


That sounds like a pay-day


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## nickvc (Apr 12, 2022)

Lino1406 said:


> Literature says. Rh will not dissolve in silver



Lino is the literature true because if so Geoff has an easy way to separate the Rh.


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## Yggdrasil (Apr 12, 2022)

I remember Lou say the same thing. 
Gold is best and Copper work, Silver not so good.
So I'm guessing Silver pick up some, but not to a usable extent.
As Nick say, maybe a sufficient method for concentrates.


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## Lino1406 (Apr 12, 2022)

Phase diagram for silver rhodium shows that. I agree that copper is more suitable


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## Geo (Apr 15, 2022)

I knew I was going to market today so I took another sample from a different spot and decided to go ahead and sell this one and get a print out. He also noted all the metals in the sample. The Rh was nearly double from the first two. They only pay on the dominant metal unless specified. So this is what I'm fighting.


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## orvi (Apr 16, 2022)

Geo said:


> I knew I was going to market today so I took another sample from a different spot and decided to go ahead and sell this one and get a print out. He also noted all the metals in the sample. The Rh was nearly double from the first two. They only pay on the dominant metal unless specified. So this is what I'm fighting.View attachment 49564


You are in similar situation that I was a year ago  but my Rh percentage was more about 1-2%. Buyer over here paid only for metals with content higher than 15%. 

14% Pt and more importantly 3,8 % Rh... That is a lot of value to be thrown off...
But you are in better position than I was, your Rh content is higher, so some home chemistry of "concentrating" individual metals could work relatively fine, and able you to get some decent percentage of Rh out as separate fraction.
If I was to do something with it, I will get rid of base metals and silver (easy one). This will bring the concentration of Rh in cemented metals even higher - you have roughly 20% "junk" inside.
Than I will focus on precipitating palladium - in smaller quantity with DMG.
Otherwise the second step will be platinum scavenging with stoichiometric NH4Cl. And then precipitation of (NH4)2PdCl6 salt. Both of tthese operation will drag some Rh to the precipitates, but I think you can get Rh fraction with more than 30% Rh content, which should be sellable.

Good luck with refining. I hope that you manage to get it out


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## justinhcase (Apr 16, 2022)

Geo said:


> The Rh was nearly double from the first two. They only pay on the dominant metal unless specified. So this is what I'm fighting.


I have found this problem.
I was introduced to the owner of a very old and well-established refinery who was very friendly, we agreed to a very good level of liquidation and assistance.
I was quite chuffed as he does not normally even take a phone call let alone talk to and help someone so small in the industry.
Was told to talk to his people.
First, his refinery manager tried to take eight years of waste concentrate and only pay me for the silver return.
I asked about the other elements and pointed out the high Rh content which I would at least like to know about, was told tuff, and asked with incredulous ruddiness "Why would you want to know that".
I was flabergasted at the deliberate misinformation by one of the largest operators in the country.
So I called the facility manager to try and talk to the owner again, once I had explained the situation she called me "A Fantasist" and would not even try and ask the owner about our conversation.
I was very insulted and disapointed.
Having to build a much larger furnace so I can process the waste myself in the largest crucible I can manage, But still have not found anyone to help liquidate the P.G.M.'s without accessing it through my rectum.


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## nickvc (Apr 16, 2022)

The problem you will have is PGM refining is still very much a closed shop and not all refineries actually refine it but concentrate and pass onto one that does who can set their own terms as to returns and what they will pay for, nice for them bad for the small refiner.
The only suggestion I have is if you have decent amounts is to either melt and get Sheffield to assay the bar or crush and sieve mix well and take several samples and have them assayed and then approach one of the refiners who does actually refine PGMs but as I said it’s very much a closed shop.


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## justinhcase (Apr 16, 2022)

nickvc said:


> The problem you will have is PGM refining is still very much a closed shop and not all refineries actually refine it but concentrate and pass onto one that does who can set their own terms as to returns and what they will pay for, nice for them bad for the small refiner.
> The only suggestion I have is if you have decent amounts is to either melt and get Sheffield to assay the bar or crush and sieve mix well and take several samples and have them assayed and then approach one of the refiners who does actually refine PGMs but as I said it’s very much a closed shop.


I did do quite a large recovery for a client that was a Payne by name and a pain by nature.
Some were in the £15,000 range.
We initially sent a sample of Platinum(II)-ammonium chloride to Sheffield who gave a very low return considering the sample was quite pure and very dry.
Turned out they had calcined the salt in an open furnace.
That did not really strike me as very efficient so I declined to settle based on that return.
So my client took the entire lot to J.M. as it was just inside their threshold for such lots.
Sadly never did hear what the return was or receive any money.
The chap told me I was an idiot for trusting him and kept several thousand pounds of equipment, sabotaging most of what he did return to the chap I sent to collect.( Don't really trust myself in close proximity to him, came very close to stuffing him into a 20,000ml reaction vessel.LOL).
So never had any real luck with P,G,M's


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## orvi (Apr 16, 2022)

Yep, interesting how this secrecy and practically divided monopoly evolved around PGMs. Why not the other metals.

That was why I invested so much time and effort to elaborate the PdPtRh "separation - recovery" method with acceptable losses. And failed miserably, to be honest. Then stuck with health issues, so I am out for several months and cannot perform experiments on PGMs. And I was relatively close to tuning the NH4Cl precipitation that way it do not drag too much Rh with it. That was the annoying step, so much Rh was trapped in the precipitates of ammonium platinate (nearly 40 % sometimes, from that 1-2% starting Rh content). Later steps were pretty much straightforward - cementing the PdRh remaining solution on zinc, boiling the precipitates with water to get rid of chlorides (practically) completely (AgNO3 test pass) and then digesting the cement with HNO3. Filter palladium nitrate and get enriched Rh cement fraction.

If I was ever to accomplish the recovery of more than 50% of the contained Rh to some enriched fraction, it will go straight here to the forum, for free and for anyone.


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## nickvc (Apr 16, 2022)

Know the man well and I had similar problems with him 
If your material is metallics and not salts you should be able to melt them depending on the PGM content and an xrf on several surfaces should tell you how good a melt you got.


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## justinhcase (Apr 16, 2022)

orvi said:


> Yep, interesting how this secrecy and practically divided monopoly evolved around PGMs. Why not the other metals.
> 
> That was why I invested so much time and effort to elaborate the PdPtRh "separation - recovery" method with acceptable losses. And failed miserably, to be honest. Then stuck with health issues, so I am out for several months and cannot perform experiments on PGMs. And I was relatively close to tuning the NH4Cl precipitation that way it do not drag too much Rh with it. That was the annoying step, so much Rh was trapped in the precipitates of ammonium platinate (nearly 40 % sometimes, from that 1-2% starting Rh content). Later steps were pretty much straightforward - cementing the PdRh remaining solution on zinc, boiling the precipitates with water to get rid of chlorides (practically) completely (AgNO3 test pass) and then digesting the cement with HNO3. Filter palladium nitrate and get enriched Rh cement fraction.
> 
> If I was ever to accomplish the recovery of more than 50% of the contained Rh to some enriched fraction, it will go straight here to the forum, for free and for anyone.


The problem is not one of recovery or refinement.
Tho that would maximize returns and eliminate the inaccuracies of the assay system.
The doorkeeper of that trade is one of quantity until you are over the required lower limit,
the only show in town J.M. will not talk to you.
Quite fascinating the world of catalytic screens for industrial use.
But because of their excellence and monopoly of the world's most P.G.M.-dependent industry, they set the standard.
Until you get above that entry-level you are stuck.
Even national-level labs do not have a controlled atmosphere tube furnace or an induction equivalent.
Just got to save until you satisfy them and cash in for close to spot.


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## justinhcase (Apr 16, 2022)

nickvc said:


> Know the man well and I had similar problems with him
> If your material is metallics and not salts you should be able to melt them depending on the PGM content and an xrf on several surfaces should tell you how good a melt you got.


I have a tube furnace, But will not have any tubes made until I have enough space to give it a dedicated area to live in, dam expensive hand made quarts tube apparatus.
I have never felt comfortable with trying to melt Pt and Pd even with a hydrogen torch.
First, you would need a pill press to form the black into something that would not simply fly out of your melting dish secondly getting a normal dish up to heat can be a challenge so upping that by six or seven hundred degrees centigrade strikes me as outside that tools productive operating level.
I would like a vacuum chamber with an induction coil, any metal can then be put into a carbon mold, brought up to its melting point under vacuum, and left to cool.
Should yield nice clean bars of all elements, but particularly facilitate Pt and Pd.
Even with that, I would still have to hand what was left over to J,M. But luckily with the value of Rh that should not be too large a lot.
Until then I will just squirrel away.


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## MicheleM (Apr 16, 2022)

Probably this is a stupid comment but, what about the idea to separate different platinum group metal salt solution via centrifugal force? Like in nuclear industry, they used to separate UF6 different isotopes. I mean if chemically is too difficult , maybe physically could be a viable option.


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## Geo (Apr 16, 2022)

justinhcase said:


> I have a tube furnace, But will not have any tubes made until I have enough space to give it a dedicated area to live in, dam expensive hand made quarts tube apparatus.
> I have never felt comfortable with trying to melt Pt and Pd even with a hydrogen torch.
> First, you would need a pill press to form the black into something that would not simply fly out of your melting dish secondly getting a normal dish up to heat can be a challenge so upping that by six or seven hundred degrees centigrade strikes me as outside that tools productive operating level.
> I would like a vacuum chamber with an induction coil, any metal can then be put into a carbon mold, brought up to its melting point under vacuum, and left to cool.
> ...


I make a saturated solution of borax and distilled water. Little more liquid than a paste, I dampen the PGM blacks with this before melting. I use a propane/oxy cutting torch and it melts PGM's like a charm. I melt in a Wesco highback melting dish exactly like this one.


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## justinhcase (Apr 16, 2022)

Geo said:


> I make a saturated solution of borax and distilled water. Little more liquid than a paste, I dampen the PGM blacks with this before melting. I use a propane/oxy cutting torch and it melts PGM's like a charm. I melt in a Wesco highback melting dish exactly like this one. View attachment 49583


It is not that I do not understand how it might be just about achieved.
It is more that I am unsatisfied with such crude methods that will result in waste and potentially Organic platnouse compounds if melted with a carbon-based torch.
People do a lot of things, but few stop to think if they should be doing so.


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## Geo (Apr 16, 2022)

I understand that. I wish I had the same options you have on philosophy. My philosophy is, use what you have, when you can.


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## justinhcase (Apr 16, 2022)

Geo said:


> I understand that. I wish I had the same options you have on philosophy. My philosophy is, use what you have, when you can.


If in an escape and evasion mode I can see them being valid tactics.
But I hope you are not in a pure survival mode.
If given the time and space I see no reason to compromise your methods.


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## justinhcase (Apr 17, 2022)

MicheleM said:


> Probably this is a stupid comment but, what about the idea to separate different platinum group metal salt solution via centrifugal force? Like in nuclear industry, they used to separate UF6 different isotopes. I mean if chemically is too difficult , maybe physically could be a viable option.


I think you will find the technology that can separate closely related elements by their mass centrifugally is very demanding and controlled.
You have mentioned why that is. to prevent the proliferation of nuclear devices.
The tolerance of such centrifugal separators is phenomenal, I do not know anyone capable of building such a system.
not to mention the power requirements for such systems.
A few years ago the CIA destroyed the enrichment facility of another nation simply by infecting their lynx-based systems with a small bit of malware which pushed a decimal point one or two places out.
The result was all their centrifuges ran over speed and BOOM!
I can think of a number of people who would pay you just about anything you can think of if you can demonstrate a working unit.


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## orvi (Apr 17, 2022)

Agreed. Small scale business is vanishing, not only from PGM industry. Naturally or forcefully.
I was just upset when I heard our 2% Rh in material wouldn´t be paid. Knowing that they will certainly be paid for it, when sell to bigger refiner who actually refine the mixture. Straight rip-off.


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## orvi (Apr 17, 2022)

Geo said:


> I make a saturated solution of borax and distilled water. Little more liquid than a paste, I dampen the PGM blacks with this before melting. I use a propane/oxy cutting torch and it melts PGM's like a charm. I melt in a Wesco highback melting dish exactly like this one. View attachment 49583


When I was melting Pt or Pd, I was using MgO cupels. Cheap, easy to handle, resistent to the temperature required for melting... And there is no possibility of carburizing the metal when melting. Also you can purchase MgO powder and press one on your own. Cheap stuff, but many times you need to contact larger facilities - they may not be willing to sell you one 25kg sack. Here, I tried two, and one was keen to sell sack for 75 euros. Not great not terrible. Last you a lifetime


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## orvi (Apr 17, 2022)

justinhcase said:


> I think you will find the technology that can separate closely related elements by their mass centrifugally is very demanding and controlled.
> You have mentioned why that is. to prevent the proliferation of nuclear devices.
> The tolerance of such centrifugal separators is phenomenal, I do not know anyone capable of building such a system.
> not to mention the power requirements for such systems.
> ...


Idea is interesting. As organic chemist, I was more interested in chromatographic separation of these elements  because it is stated in literature, and it works. However, not for hundreds of grams... But that ease of separation is so tempting - took a syringe with soluble complexes of the PGMs, inject them to the column of stationry phase, start pumping mobile phase (buffered water) and you separate individual PGMs salts as fractions. When you have transparent glass or plastic column, you can clearly see bands of different colours going down. If you get the mobile phase right, you get 99+% separation/purity.

With centrifugal separation, I have no idea how big the force must be to start moving up molecules eg in solution. I will need to calculate it... Also very clever idea - Pt is nearly twice as dense as Pd. So this separation could be accomplished more easily (I assume) than uranium isotopes. But I´m staying rational and trust the old NH4Cl could do something for me


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## kurtak (Apr 17, 2022)

Hmmm - let's see if we can get back to solving Geo's problem - which is (first) the recovery of "all" the PGMs (including the Rh) from the 9 pounds of filter ash

It would be nice if it was as simple as leaching the ash - but it's not due to the difficulty of trying to dissolve the Rh out of the ash with wet chemistry

As we know - Rh (even finely divided) is resistant to AR --- for (complete) wet chem leaching of the Rh Chlorine or Bromine would be required - the problem there is keeping those elements in solution "long enough" for complete dissolution of the Rh - I believe the leach needs to be done under pressure or vacuum (don't remember which) 

As a side note; - I am FAR from being an expert on all things PMG - what I do know is that wet chem dissolution of Rh is at best a difficult task

This brings us back to smelting for the recovery of the metals in the ash (including the Rh)

It has already been pointed out that silver is not a good collector for Rh

However - as Lino pointed out -----------



Lino1406 said:


> I agree that copper is more suitable



& as Lou pointed out in this thread -----------



Lou said:


> How this is done industrially is with cryolite as the flux *and fine chopped copper wire* inside of a furnace you could drive a small truck into.



Note here; - cryolite is only needed in the flux when ceramics are involved as cryolite dissolves ceramic at "high" temp

So - IMO - (& if were me) smelting with copper is exactly what I would do to recover the metals (including the Rh) from this ash

As another note; - based on the report Geo posted - yes there is "some" silver in the ash - BUT - it is so very low (2.9 %) that it will have NO effect on the collection of the Rh - silver is only a problem (for the collection of Rh) when it (silver) is the predominant metal in the smelt 

Once geo has recovered his metals from the ash by way of smelting with copper as his collector he should be able to get very near complete separation of the metals from his smelted dore with wet chemistry



Geo said:


> So this is what I'm fighting.



Geo - IMO - smelting your ash with copper (as collector) is the first step in the recovery of the metals (including Rh) from your ash - once the metals are recovered (collected) from the ash we can go to wet chem separation on the dore

With proper ash/flux/copper ratios & proper flux ingredients you should be able to achieve 97 - 98 % recovery of your metals with your only real losses being small beads of metal that hang up in the slag of your "first" smelt pour - & those beads are recoverable 

One more note; - you want your copper to be "fine" so it mixes in well with flux/ash for proper collection - as in "fine" chopped wire - or powder (*clean *copper cement would certainly work)

If you need help with ash/flux/copper ratios &/or flux ingredients let me know & I will be more then glad to help

Kurt


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## orvi (Apr 17, 2022)

kurtak said:


> Hmmm - let's see if we can get back to solving Geo's problem - which is (first) the recovery of "all" the PGMs (including the Rh) from the 9 pounds of filter ash
> 
> It would be nice if it was as simple as leaching the ash - but it's not due to the difficulty of trying to dissolve the Rh out of the ash with wet chemistry
> 
> ...


I have experience with copper "inqartation" of PGMs (in my case 87%Pt 13% Rh to the final mass of 20% PGMs in copper). It alloys OK, drive past 1200°C and it is fine. Still copper-ish colour, but whitened considerably. Reaction with nitric is much more tame than plain copper. Dissolves very easily in nitric, but nitric also dissolve some platinum to the juice. But precipitate formed cannot be filtered easily.
When you have Cu dore with PGMs, it will be very easy to dissolve it in AR. Sponge produced from Cu inquart is extremely fine, particles so small that they refuse to settle completely even after one week, and were inert to my trials of efficient flocculation. So taking this and putting it straight to AR would bring Rh to solution relatively easily, i assume.

I can imagine next putting the copper bar into the bucket of AR solution (not sure if it is necessary to de-nox, since Rh form nitrito complexes... but these should be reduced also), aerate and precipitate the PGM cement. This could be workable for next chemistry, sponge could be dissolved in HCl/Cl2 and you have no salts in solution, evaporate chlorine and majority of HCl and you are prepared for Pt drop with NH4Cl - no NO complexes of Rh, no excess nitric, no excess of HCl (lower the solubility of not only ammonium Pt salts but also Pd and Rh ammonium salts).


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## Geo (Apr 17, 2022)

Most of what was in the report is not a mystery to me as how it got in there. Zinc and iron is understandable as I have used both to cement with. Zinc turnings and steel wool. All the rest are found in electronics except for bismuth. I have never used it before and it's never been reported in any other metal I've recovered. Is bismuth in solder? If not, what components, if anyone knows, in electronics that contains bismuth?


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## justinhcase (Apr 17, 2022)

orvi said:


> Idea is interesting. As organic chemist, I was more interested in chromatographic separation of these elements  because it is stated in literature, and it works. However, not for hundreds of grams... But that ease of separation is so tempting - took a syringe with soluble complexes of the PGMs, inject them to the column of stationry phase, start pumping mobile phase (buffered water) and you separate individual PGMs salts as fractions. When you have transparent glass or plastic column, you can clearly see bands of different colours going down. If you get the mobile phase right, you get 99+% separation/purity.
> 
> With centrifugal separation, I have no idea how big the force must be to start moving up molecules eg in solution. I will need to calculate it... Also very clever idea - Pt is nearly twice as dense as Pd. So this separation could be accomplished more easily (I assume) than uranium isotopes. But I´m staying rational and trust the old NH4Cl could do something for me


The first part sounds more like the purification of LSD than any metallic use I can think of, very effective for small samples but not very scalable.
The second, even the engineering for a centrifugal concentrator is beyond most all but the best available engineers.
Once you take that concept down to the molecular level that is strictly governmentally controlled technology the same as Exploding Bridgewire and flash detonators.


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## orvi (Apr 17, 2022)

Geo said:


> Most of what was in the report is not a mystery to me as how it got in there. Zinc and iron is understandable as I have used both to cement with. Zinc turnings and steel wool. All the rest are found in electronics except for bismuth. I have never used it before and it's never been reported in any other metal I've recovered. Is bismuth in solder? If not, what components, if anyone knows, in electronics that contains bismuth?


Bismuth is found in some exotic solder mixtures, but not very often. Lead-free solders are practically pure tin with very small percentage of antimony, copper or silver. It is also used in thermal protection fuses - non-reversible ones, where an low melting alloy wire is used. Bismuth is sometimes in this composition. I bought bismuth once from Aliexpress for like 20 bucks a kilo (intended to use it as collector metal instead of lead). Very brittle and crystalline metal.


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## snoman701 (Apr 17, 2022)

nickvc said:


> The problem you will have is PGM refining is still very much a closed shop and not all refineries actually refine it but concentrate and pass onto one that does who can set their own terms as to returns and what they will pay for, nice for them bad for the small refiner.


I feel like it depends. Good for the small scale refiner, bad for the small scale collector / assay / seller



orvi said:


> Agreed. Small scale business is vanishing, not only from PGM industry. Naturally or forcefully.
> I was just upset when I heard our 2% Rh in material wouldn´t be paid. Knowing that they will certainly be paid for it, when sell to bigger refiner who actually refine the mixture. Straight rip-off.


Was it ever there in the PGM industry? 

This volatility doesn't exactly help either. It's considerably harder to hedge small amounts that a little guy without a $1,000,000 bankroll can buy...the guys trying to hustle with $10,000 don't stand a chance, and the guy with $100,000 is going to struggle.


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## justinhcase (Apr 18, 2022)

snoman701 said:


> I feel like it depends. Good for the small scale refiner, bad for the small scale collector / assay / seller
> 
> 
> Was it ever there in the PGM industry?
> ...



You are only looking at the size of an operations float, that is free capital.
That is not the hardest part, The hardest part is the investment in facility and infrastructure that will let you turn over your float safely.


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## snoman701 (Apr 18, 2022)

Not necessarily. Being small can be quite the advantage. What is "safe" for a single man operation is negligence for an environment where you have employees. Mind you I am not talking about processing of Ru, Ir, Os....the only one of those worth chasing for a little guy is Ir, and you better be getting it free because the premiums on the sale are going to eat your profit quick. 

The biggest setback is the cost of entry for analytics for the pgm's. Lou will tell you that the quantitative chemistry always wins, but you'll need ICP spectrometry for efficiency. You simply can't do it with AAS, and XRF is too inaccurate.

In Geo's case here, the first thing I'd do is send it out for a proper nickel sulfide fusion / assay to make sure he actually has the anticipated amount of Rhodium present and isn't chasing a $35,000 dream.


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## justinhcase (Apr 18, 2022)

snoman701 said:


> Not necessarily. Being small can be quite the advantage. What is "safe" for a single man operation is negligence for an environment where you have employees. Mind you I am not talking about processing of Ru, Ir, Os....the only one of those worth chasing for a little guy is Ir, and you better be getting it free because the premiums on the sale are going to eat your profit quick.
> 
> The biggest setback is the cost of entry for analytics for the pgm's. Lou will tell you that the quantitative chemistry always wins, but you'll need ICP spectrometry for efficiency. You simply can't do it with AAS, and XRF is too inaccurate.
> 
> In Geo's case here, the first thing I'd do is send it out for a proper nickel sulfide fusion / assay to make sure he actually has the anticipated amount of Rhodium present and isn't chasing a $35,000 dream.


Outside the realms of industrial catalyst and aircraft supper alloy there is very little P.G.M. to have.
Even in the scrap jewelry trade, you are talking a few grams of Pt and Pd even less Ru for every kilo of gold you have through.
They are detectable in electronics but the amount you would need to process to recover any financially expedient amount would by necessity bump you up to an "industrial" level of operation.
What is a challenge for a well-funded lab is quite likely a danger for less equipped individuals to try no matter what is being said on YouTube.


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## kurtak (Apr 18, 2022)

orvi said:


> Agreed. Small scale business is vanishing, not only from PGM industry. Naturally or forcefully.
> I was just upset when I heard our 2% Rh in material wouldn´t be paid. Knowing that they will certainly be paid for it, when sell to bigger refiner who actually refine the mixture. *Straight rip-off.*


Per the bold print - I have to disagree (at least to a point)

As we know - when we start working with alloys that contain 2 or more metals we need to go through more steps/processes to get a separation of those metals

Therefore - the percentages of each of the metals needs to be high enough to cover the cost of separating each metal

Example - say someone sends me a 1 or 2 kilo batch of say gold filled &/or gold plated jewelry to process

In that 1 - 2 kilo batch there is likely to be "some" GF or GP *on silver* (this is of course being processed for the gold)

So - in step 1 we put the GF/GP in nitric to dissolve the base metals (& "*maybe*" some silver) in order to get our gold foils

Step 2 - wash all the nitric leach out of the foils so we can move to AR on the gold foils - the gold being what the clients is going to be paid out on (so that is a no brainer - the client gets there percentage - I - as the refiner get my percentage) --- in other words - the steps in the refining "for the gold" are all part of the percentage agreement between client/refiner - which includes step 1

However - in this case - step1 is/was part of the process of going for the gold & MOSTLY a step to remove base metals

It just happens - that in that step - you "may" (or not) end up dissolving "some" silver

If - in the event you dissolved "some" silver in step 1 - you now have to do additional steps to recover that silver

Let say (for the sake of putting it in perspective) that in this batch we dissolved 1ozt silver

The "additional" steps I need to go through to recover that 1 ozt silver (keeping in mind that this needs to be done on "the batch" if you are going to "account" for it)------------

Step 1 - cement the silver from the nitric leach (in which I am using up some of my "personal" copper as will as the time for this step)

Step 2 - washing the chem out of silver cement - more time

step 3 - dry the cement - more time plus electric to run the hot plate

Step 4 - melt the dried cement - more time & torch gas

Bare minimum time to get this done = 4 hours (likely ALL DAY - though you can do other things between steps)

Current price for silver at $25.91 (call it $26) divided by (at best) 4 hours = $6/hour (let alone my copper, electric, gas, etc.) --- & then expect to pay the client a percent back on that silver ????

Lets just say the client has this expectation that he should get 80% silver back

$26 X .2 (my supposed %) = $5.20 divided by 4 hours (at best) = $1.30 (call it $1 after copper, electric, gas, etc.)

Sorry - but I don't work for a dollar per hour (in order to account for the silver "in this case") --- If I did - I would loose most if not all my "profit" made on accounting to client for the gold in this batch & would SOON be out of business

Something that stuck in my head when I read Hokes book - she said - "the silver - if worth while"

Sorry - but - in the above case - I am not ripping the client off by not paying him on the silver - the fact of the matter is - recovering that silver isn't even paying me - let alone paying the client

At best - that silver is only "helping" to covering "overhead" I have to be set up for refining in the first place --- so that I can pay out a fair price on the "target" metal 

Something that stuck in my head when I read Hokes book - she said - "the silver - IF worth while" !!!

The above holds true when dealing with dore metal that has predominant metal(s) but also has LOW percentage of other metal(s)

For what it's worth

Kurt


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## orvi (Apr 18, 2022)

kurtak said:


> Per the bold print - I have to disagree (at least to a point)
> 
> As we know - when we start working with alloys that contain 2 or more metals we need to go through more steps/processes to get a separation of those metals
> 
> ...


With last sell, PGMs were cemented and melted (since no sucess with good separation in our hands). 55% Pd 40% Pt 2% Rh. PdPt were paid allright, but no payment for Rh. I accept that it could be difficult to get it out of the mixture, but when it comes to actual refining (through all the persons in the ladder of "middlemans" who rarely know anything about refining here), the Rh will be extracted anyway - no one serious and established refinery will throw away Rh. Maybe dispersed as unleachable traces in vast volume of ceramic or oxide matrix, but not in metal bar form.
In 1 kg of the aforementioned melt, Rh value accounts for more than 12 000 USD. No way that it wouldn´t be economical to extract it.
I will live happily with 30-40% offer on Rh (can swallow that "it´s a low content, can´t pay more" excuse), but saying that I won´t pay you on that is straight rip-off.
On the other hand, these are the terms offered. We could decline them any time  but that does not change my mind.

Your example with silver is certainly legit, and silver can be pain to extract and monetize. Volume is the key.


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## justinhcase (Apr 18, 2022)

orvi said:


> In 1 kg of the aforementioned melt, Rh value accounts for more than 12 000 USD. No way that it wouldn´t be economical to extract it.


$12,000 an oz, $617,294.33 a kilo they are making a killing.


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## shintoc (Apr 19, 2022)

orvi said:


> Yep, interesting how this secrecy and practically divided monopoly evolved around PGMs. Why not the other metals.
> 
> That was why I invested so much time and effort to elaborate the PdPtRh "separation - recovery" method with acceptable losses. And failed miserably, to be honest. Then stuck with health issues, so I am out for several months and cannot perform experiments on PGMs. And I was relatively close to tuning the NH4Cl precipitation that way it do not drag too much Rh with it. That was the annoying step, so much Rh was trapped in the precipitates of ammonium platinate (nearly 40 % sometimes, from that 1-2% starting Rh content). Later steps were pretty much straightforward - cementing the PdRh remaining solution on zinc, boiling the precipitates with water to get rid of chlorides (practically) completely (AgNO3 test pass) and then digesting the cement with HNO3. Filter palladium nitrate and get enriched Rh cement fraction.
> 
> If I was ever to accomplish the recovery of more than 50% of the contained Rh to some enriched fraction, it will go straight here to the forum, for free and for anyone.


Always willing to share information as well. We spent the last 10 months upgrading our smelting facility, and equipment for Elctroplating and Induction Furnaces. 
Hope the above turns out well, if needed, PM me directly.


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