# My latest Pd drop



## kjavanb123 (Aug 3, 2016)

All,

Hope everyone is well. I just percipitated 19g of Palladium using DMG for a client. Just like to share the photos and thanks the forum.


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## Geo (Aug 3, 2016)

That's 19g?


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## kjavanb123 (Aug 3, 2016)

This was recovered from a copper based solution, total of 7 liters. I tested 600ml of solution with DMG and recovered 1.6g of refined Pd sponge, so I figured in 7 liters of the same solution should have around 19g of Pd.

The source of his materials are cell phone boards.

Will keep you posted on final Pd sponge weight and Pd button.

Regards
Kj


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## Topher_osAUrus (Aug 3, 2016)

Wow.

Thats some very voluminous pd!

Very pretty yellow


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## kjavanb123 (Aug 3, 2016)

God blesses freechemist's soul, as it was his post about DMG formula that helped me on this project.


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## samuel-a (Aug 3, 2016)

humm... Why DMG??


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## FrugalRefiner (Aug 3, 2016)

kjavanb123 said:


> God blesses freechemist's soul, as it was his post about DMG formula that helped me on this project.


Remember that freechemist died because of his exposure to PGM salts. If you really feel it's worth it to expose yourself, or those who work for you, to the risk, at least put on, or have your workers put on, some gloves! 

Dave


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## 4metals (Aug 3, 2016)

DMG is quick and easy and voluminous which is why it finds use as an indicator and in assays. There are alternatives that are cheaper.


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## kjavanb123 (Aug 3, 2016)

All,

My solution was mostly copper nitrate mixed with palladium nitrate and some 400g silver.

I tried a 600ml of solution, with silver in it, and precipitated palladium with DMG, but the color of the salt was not canary yellow, so I figured silver also formed a complex with Palladium.

So I dropped silver as its chloride salt from the solution first, filtered it and did the DMG.

As for alternative and cheaper methods, I only learned sodium chlorate, zinc cementing, both of which at least I have worked with solution that are palladium mostly.

Since this solution was mostly copper based, zinc would not work since it would cement both copper and palladium from solution.

Using sodium chlorate, on this 7000ml solution would have taken a long time to concentrate the solution to be able to proceed with sodium chlorate.

I only used 60g of DMG, for this 7000ml solution and got to the canary salt part quickly. Filtering and conversion to black powder did not take more than 2 hours. 

As for the safety, we all wear mask, and I wore gloves since I was doing the work, also the Pd salts are wet when we work with them, I assume they pose smaller threat as they can not be air bourne.

Regards
Kj


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## Lino1406 (Aug 4, 2016)

how about dropping with formic acid?


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## kjavanb123 (Aug 4, 2016)

I am against the killing of millions of ants to make formic acid :wink: 

I like the zinc powder and hcl acid method better.

Regards
Kj


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## Lou (Aug 4, 2016)

You didn't follow up on the resin?


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## kjavanb123 (Aug 4, 2016)

Hi Lou,

Yes I did and recieved an offer from them as well, just trying to allocate capitals for it.

I will traveling globally and with their volumes of materials that IBC system comes very handy.

Here is the final Pd sponge being dried,







Thanks and regards
Kj


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## kurtak (Aug 5, 2016)

Lino1406 said:


> how about dropping with formic acid?



Lino

I was not aware that you could "drop" Pd with formic --- Hokes (on page 158) instructs using formic acid to reduce PGM salts that have been precipitated from solutions (which I have done) & as well there are other instructions posted here on the forum for using formic acid to reduce PGM salts - after they have been precipitated --- but this is the first I have heard of using it to "drop" the PGMs

could you elaborate ?

Kurt


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## Lou (Aug 5, 2016)

It is not entirely selective and takes several hours of good heat..

You can also use ascorbic acid.


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## jason_recliner (Aug 5, 2016)

kjavanb123 said:


> I am against the killing of millions of ants to make formic acid :wink:


You wouldn't be, if you'd been bitten by a dozen myrmecia the size of crickets. Each one with a sting like being smacked with a wet lettuce, wrapped around a #5 iron. I discovered the nest by kneeling on it, weeding.


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## Lino1406 (Aug 5, 2016)

The process I know is mixing boiling Pd solution with boiling 15-50% formic acid solution or acidic ammonium formate. Sometimes it is immediate. And there is no need to kill ants for it - although some say they are the successors of human species. Ref: C.W.AMMEN


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## samuel-a (Aug 5, 2016)

kurtak said:


> Lino1406 said:
> 
> 
> > how about dropping with formic acid?
> ...




The terminology is a bit problematic here.
In our perspective, a 'drop' or precipitation is a physical occurrence, which usually is derived from a chemical reaction, it could be:
- Reduction - A good example is reducing gold from solution with SMB, this reduction causes a precipitation action.
Oxidation - An example for that could be found with Pd, where one would oxidize Pd(II) salt in soultion to form insoluble Pd(IV), and thus precipitate the salt.
Displacement - The classic example for it would be the precipitation of Silver Chloride from silver nitrate solution. The Chloride ion replaces the Nitrate ion to produce the insoluble AgCl.

Fromic acid is a reducing agent in that aspect (and not a selective one as Lou advised), it will reduce PGM's and thus drop it out of solution. 
The chemical action would be much similar as tough it would have happened with the precipitated colored salts.
As side note - i found that precipitating dirty PGM's with formic acid usually results in an ink like suspension which is hard to deal with.


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## kjavanb123 (Aug 6, 2016)

Hi,

I think confusion dervied from the usage of formic acid in regards to conversion of yellow salt to Pd sponge instead of zinc and hcl cemeting which I used.

And not the usage of formic acid to precpitate palladium from solution.

Regards
Kj


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## kjavanb123 (Aug 6, 2016)

All,

Some update on this project. After we dried the Pd sponge we produced, it weighs 53g which is almost 3 times as much as expected of 20g.

In order to test it, we melted 2g of Pd spong powder using oxygen torch, which I thought was forbidden to use on Pd melting, but mu client who is also a smelter melted 2g sample powder into the following button that weighs 1.7g.




So I suggested he melt the entire 53g of Pd sponge using oxy hydrogen torch. I shall continue this project and report the latest.

So today we melted the remainder of 53g Pd sponge using oxygen torch and it melted to this 43g ingot shape as following photos,











Off to go doing assay on Wed.
Best regards
Kj


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## kjavanb123 (Aug 16, 2016)

All,

Assay result on 42.6g palladium ingot shows 828. I wonder is that due to the fact the exterior layer of ingot is oxidized during melting with oxygen torch?

Regards
Kj


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## g_axelsson (Aug 16, 2016)

I think we need a few more details... What type of assay? What was the main contaminant? What fuel was used to melt it? In what type of vessel was it melted?

I have a hard time to see a 17.2% weight contamination by oxygen, but I might be wrong. I'm no expert on PGM:s.

Göran


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## Lino1406 (Aug 22, 2016)

To keep Palladium from oxidation (in the presence of oxygen) - temperature > 750C
Ref: last chapter of "30 and more recovery procedures"


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## kjavanb123 (Aug 22, 2016)

Hi,

As for melting, my client used its oxygen gas torch. As for assay they did not roll the ingot, just used laser for some sort of x-ray to assay.

Lino,
If you keep temp to over 750 degrees, then once it cools down it will gets oxidized again.

Regards
Kj


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## Nadeem (Dec 23, 2022)

kjavanb123 said:


> God blesses freechemist's soul, as it was his post about DMG formula that helped me on this project.


Hi bro plz explain the method for me ialso hve 28 litre of nitric acid wit Pd base metal is iron and copr


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## kjavanb123 (Dec 26, 2022)

Nadeem said:


> Hi bro plz explain the method for me ialso hve 28 litre of nitric acid wit Pd base metal is iron and copr



Hi Nadeem

Sorry about the late response. If I were you and didn't know how much Pd is in 28 litre solution. 

I would take 1 litre of that solution, then prepared DMG solution based on the following formula. 

You heat 100ml of water to near boiling, add 4g of NaOH (lye) slowly to the water. 

Then you add 5.81g of DMG to above and stir till all of it dissolves. 

You can add the DMG solution to your 1 litre sample, if palladium in solution a canary yellow powder form, wait till it settles down then test your solution for Pd. 

If negative then you filter and wash the yellow DMG Pd salt then rinse it to a beaker add zinc powder and mix it with yellow salt, then slowly add hcl and stir till solution is gray or coloress. 

You can then dry and weigh the black powder which is element Pd then you multiply that by 27 to give you the Pd in 27 litre. 


You then calculate how much DMG and lye water needed to drop the Pd from 27 litre.


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## lazersteve (Dec 29, 2022)

Here's a Pd button I made recently. No ants were harmed in its production nor was any DMG used. No fancy smelting or furnace. All simple wet refining work done with basic chemicals, nothing you don't (correction: shouldn't) already have in your gold refining lab. 

Source material was contaminated with an alphabet soup of aerospace grade alloys which were also nearly unharmed in the process. Other contamination include alloyed Au, Ag, and Pt.
View attachment highpurity_pd.mp4 (1440p).mp4


XRF done by the buyer shot 99.9%+ which is the maximum they allow on their payouts 

Total processing time from recovery to refined button was less than 2 days and it was melted in a clean open top silica dish using an oxy/propane torch. 

As with any process used in refining it's not about fancy chemicals or techniques, it's about proper application of an appropriate technique that performs the job to the expected purity standards.

Steve


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## kurtak (Dec 29, 2022)

lazersteve said:


> All simple wet refining work done with basic chemicals, nothing you don't (correction: shouldn't) already have in your gold refining lab.


Steve could you elaborate a bit more ?

If no formic & no DMG then what ? (that would be *basic chem* in *gold* refining lab) 

Most (but not all) chems for gold precipitation are "selective" for gold

Ascorbic maybe ???

By the way GOOD to see back & posting   

Kurt


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## lazersteve (Dec 29, 2022)

No ascorbic acid.

In my book basic means the 3 primary mineral acids (preferrably in their "dry" forms), a base of your choice, and SMB for chemicals. Add to this list a few fundamental lab tools (pH paper, beakers, funnels, and filters) and you too can produce "high" purity Pd with minimal effort and cost.

At $250+ a kilo DMG is a dead end for the refining of Pd, not to mention the unwieldy nature of the massive precipitate it forms. It's great for testing, but stinks (in more ways than one) from a recovery/refining perspective. After spending thousands of USD on DMG using it all in my Pd recovery processes (just as Kevin demonstrated above) I hit the books and found a much simpler and direct method that is both elegant and economical. Lastly, despite the accepted idea among the masses that DMG is solely selective for Pd, I can tell you first hand experience (and back it up with numerous photos) that it is not unless the reaction conditions are properly controlled. Drag down and entrapment are two major downsides to using DMG for Pd on any scale above a few grams.

Formic works when all the conditions are controlled properly, but isn't required as it forms in situ in many instances as an intermediary. It's one of those fun to try methods (been there done that), but from the standpoint of ease of use and the most direct route from soup to nuts...formic is out in my lab.

I'm still not entirely sure why PGM recovery and refining techniques have "evoled" to their currently accepted methods, but I can assure you all the whoopla surrounding them is more of a method of obstruction than good sound ends to the means of producing relatively pure PGMs. That's not to say the currently accepted techniques don't work, but they are not required to obtain PGMs of an acceptable sellable purity. Additionally, the proclaimed hazards of PGMs and their toxicity are real and perhaps this is one contributing factor as to why the more direct methods have been brushed under the proverbial rug by history. If something is made out to be complicated and difficult, few will attempt it, let alone unlock the secrets it holds.

Sorry for the long winded reply. This is a subject that I have literally devoted years of my life researching and discovering for myself here in my humble lab so it is dear to me.

Steve


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## orvi (Dec 29, 2022)

lazersteve said:


> No ascorbic acid.
> 
> In my book basic means the 3 primary mineral acids (preferrably in their "dry" forms), a base of your choice, and SMB for chemicals. Add to this list a few fundamental lab tools (pH paper, beakers, funnels, and filters) and you too can produce "high" purity Pd with minimal effort and cost.
> 
> ...


I work with Pd a lot now. My first and biggest variable of concern is time. I refine Au and Ag materials (various common and totally uncommon feeds, different processes etc...) and also quite a bit of PGMs (mainly Pd and Pt, less Rh, in the future maybe Ir - which I only collect as enriched fractions for now). 
Yet very unplesantly looking, I still use AR for kilos of pins/transistors/plated stuff and mixed Au e-scrap, lye/sugar for silver (but moving forward to iron cementation slowly) and mainly formic/DMG for Pd - sometimes DMG. Ladden with lots of pyrometallurgy for complicated matrixes and oxidative/evaporation cleaning of PGM alloys from Cd,Sn,Pb and Bi at very high temperatures.

It may sound completely nuts, but with dirty, mixed, complicated and non-homogenous materials I didn´t found better approaches suited for me (yet). And I had quite a venture with PGMs (few posts from me regarding separation of low Rh from PtPd etc...). I tried unhealthy ammount of various precipitants, SX, hydrolyses, reducing and oxidizing agents... From old NH4Cl to very interesting precipitants like mercaptobenzothiazole, SX with standard and also very uncommon solvent mixtures, various alterations of classic NH4Cl platinum drop, fractional crystallization of Na2PtCl6 contamined with Rh (relatively nicely working technique, but a bit tiring - altough done in very low volume/quantity ratio) etc... Combined hundreds of hours of doing "private" research with real samples and "made out" samples from pure PMs to prove the concept. Surely, big guys are doing better, more smoothly and nicer. But I didn´t have the ability or luck to find better working conditions for established feeds I currently have.

And despite all this, I still use DMG as precipitant of choice for bulletproof and very sharp separation of Pd from other PGMs/BM starting "soups". 250+USD/kg DMG is from local vendors - which get it from China for less than 80USD/kg - and I am getting DMG directly from China for that 80USD/kg. With like 8-10 component liquid soup of PtPdRh and you name what base metals, I get 99,8% Pd in less than one day to the ingot. Smoking loss of Pd can be minimized below 0,5%, and you catch all on the mineral wool plug (later toss to the MLCCs melt to recover the Pd, so overall no loss). Filtration of big batches is relatively horrific looking, but nothing that bad if you have setup for filtration of big volumes conveniently.

So that´s it. Not very nice and "refined" technique, but put on the sheet of paper - cheapest I currently have in hand in terms of material costs, labor time and efficiency/result delivery (combined). DMG to remove Pd out (after slight pH adjustment to positive numbers), two boiling hot, slightly acidic washes, one controlled pyrolysis/incineration and you have very nice Pd sponge in hand. If I do not need to go with DMG, I am more than happy to proceed without it.

I assume you clean the Pd by hydrolytic precipitation of base metals (raising pH), leaving pure Pd solution, which is then reduced to Pd. Just my thought, how I would do it with chemicals you mentioned. I also tried this - but as I am always dealing with AgPd alloys, silver removal is essential before Pd cleaning. Hydrolytic separation of silver and Pd work - but I never achieved desired goals with it (not sharp in my hands). So anyway, silver need to be removed beforehand and Pd is then dropped. Maybe there is some trick to better pack the gooey BM hydroxide cake formed, but for me it was always tedious using easily accessible coagulants/flocculents and filtration (high retention in cake). So while I needed to boil the pot anyway, formate is the easiest method to perform next. And also that is the method type I like, you set it for boiling and let it be for several hours, doing other jobs and Pd just settle to the bottom when you arrive back to it. No further care 

But I very like your approach to things, elaborating new practices is essential thing to move further. And also reviving old techniques for convenience  like peroxide for gold dissolution  As a professional chemist, I cannot agree more.


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