# Palladium Complete Sequel



## RaoOvious (May 20, 2013)

One ounce troy Palladium refining sequel........


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## RaoOvious (May 20, 2013)

Sequel Continued......


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## RaoOvious (May 20, 2013)

Sequel Continued.......


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## Dan Dement (May 20, 2013)

Have you tried melting the sponge into metal?

Dan


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## Lou (May 20, 2013)

I would've taken the extra time to digest in ammonia and go through the diammine given the color of the supernatant indicating nickel.

It's been my experience that the purer these salts are, the more voluminous and fluffy they end up.

Also, your sponge has a weird look relative to our output and the industry standard for it.

We go for filterability--here's an example of the sponge we make. Prior to calcination.


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## RaoOvious (May 20, 2013)

Dan,

As the sponge is melted,I would post.

Lou,

Green color is due to chlorine source(NaOCl) which was overused.Even during reduction more NaOH was used then normal Stoichiometry requires due to presence of Chlorine in Palladate.

As regards the look of my sponge,this was oven dried without fully neutralizing the reduction supernatant (was in a hurry),so it dried in an ammoniacal enviroment.The end use of this sponge is destined for a Jeweler.

Lou I second your observation regarding the voluminous and fluffy appearance.


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## 9kuuby9 (May 20, 2013)

Great post!

The Pd sponge somehow looks like small expensive coal bricks


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## Dan Dement (May 20, 2013)

As Lou will agee. getting .999 pure Pd is not a simple operation. As I have a little experience, getting it from sponge & powder into a castable metal is not so easy either. I have been called by friends, Dan the Devil as I had to make a pact with the devil to be able to get it to cast. When you can go get Maple Leafs at $40. over spot, makes you appreciate the difficulty that your jeweler customer is going to have. Cast it without a Vacuum or Argon is going to cause lots of problems with post cracking of the metal. Difficult path that you are going down. Best of luck & success.

Dan


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## Lou (May 20, 2013)

You can O2/H2 melt the material and it will look shiny but it cannot be made into a casting. Have learned this the hard way.

It can only be vacuum melted and doing that from the sponge is a difficult proposition, as most induction melters' work coil frequencies are too low to melt anything less than bulk metal. You can do it if your customer starts with a heel made from the pure metal or alloy thereof.


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## RaoOvious (Jun 4, 2013)

Below is the melted Palladium button sequel as promised,weight 27.1 grams melt loss almost 2.75%..........


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## RaoOvious (Jun 5, 2013)

This extra series might help as a visual guidance for a reasonably complete Palladium Refining Processes.. The raw weights 25.5 grams which is being refined....


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## RaoOvious (Jun 5, 2013)

Without going through the underlying process already visualized, we are starting direct from (NH4)2PdCl6......


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## RaoOvious (Jun 5, 2013)

Note Picture 10:

(FOR COMPARISON PURPOSE ONLY)

This Tetraammine Palladium II chloride is contaminated with other base metal which also form ammine complexes with ammonia i.e Nickel,Cobalt,Copper and Chromium etc which usually color blue or green.To make sure the final yellow Diamminedichloro Palladium II salt is free of base metals,it should be again digested into ammonia to match with the standard transparent color with yellow tint.


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## RaoOvious (Jun 5, 2013)

Yellow DiamminedichloroPalladium II salt was reduced by Formic acid and 6.25 M NaOH.Resulting beautiful settling Palladium Grains are shown.......

Hope everybody would enjoy and learn from this series.


Rao


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## Lou (Jun 5, 2013)

Good stuff!


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## JHS (Jun 5, 2013)

Absolutely enjoyed it
Absolutely do not understand,but thanks for sharing.
If you are interested in toll refining some of the brick red,pm me
john


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## RaoOvious (Jun 6, 2013)

Appreciated all the comments.

John, If you want your brick red to be toll refined then pm me in detail of what you have etc.Only then I may suggest my opinion.

Rao


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## lazersteve (Jun 6, 2013)

John,

If you have Pd to the brick red stage, you've done most of the hard work. It's all downhill from there.

Steve


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## RaoOvious (Jun 6, 2013)

John,

Or otherwise would second Steve's stance.


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## JHS (Jun 6, 2013)

Steve,Rao.
Last time Ithought it was all down hill,the ride in the fast moving soap box racer was fun
until i realized the only thing at the bottom of the hill to stop me was
a bulldozer blade.
john


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## necromancer (Jun 7, 2013)

very nice, thank you

i am running 3.5 lbs of MLCC's, your post helps


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## RaoOvious (Jun 8, 2013)

necromancer said:


> your post helps



That was its purpose precisely.Good luck with MLCC's.....


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## 9kuuby9 (Jun 16, 2013)

Very helpfull!

So if I understood it correctly, starting from (NH4)2PdCl6; you filtered the sponge red and then digested it in Ammonium hydroxide, from their you added HCl to precipitate Yellow Palladium salt (DiamminedichloroPalladium II Chloride) and then filtered the yellow sponge.

How did you reduce the Pd metal from their using Formic acid and NaOH?

and did you wash all your Pd salt sponges residuals with a cold solution of 15% ammonium chloride?


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## RaoOvious (Jun 17, 2013)

9kuuby9 said:


> So if I understood it correctly, starting from (NH4)2PdCl6; you filtered the sponge red and then digested it in Ammonium hydroxide,from their you added HCl to precipitate Yellow Palladium salt (DiamminedichloroPalladium II Chloride) and then filtered the yellow sponge.



Yes except,before adding HCl you must filter the transparent yellow Palladium Solution.And i wont name the Palladium salts as 'sponge red and yellow sponge'.



9kuuby9 said:


> How did you reduce the Pd metal from their using Formic acid and NaOH?



Add DI water(Approx. 20 ml for 1 gram of Palladium or 10 ml for 1 gram of yellow salt) to Yellow diammine salt,then add 1 ml of formic acid for 4 gram of yellow salt or 0.5 ml for 1 gram of Pd metal in yellow salt i.e(1 gram yellow salt contains almost .5 gram of Pd metal),heat them upto to 65 C,then slowly add 6.25 M(25% NaOH solution or 250 grams NaOH per litre of water) NaOH solution such as for 1 gram metal or 2 gram yellow salt 1.7 ml of 6.25 M NaOH should be added.Suddenly after some greenish look all the yellow metal would be converted into beautiful settling Pd sponge. 



9kuuby9 said:


> and did you wash all your Pd salt sponges residuals with a cold solution of 15% ammonium chloride?



Red (NH4)2PdCl6 should be specially washed whereas Yellow Diammine can also be washed with cold DI water instead of 15% ammonium chloride.


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## 9kuuby9 (Jun 17, 2013)

RaoOvious thank you for the answer I really appreciate it 

After converting the Yellow diammine salt to Pd metal; is their any need for washes?

Or just regular Hot Di. water washes?


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## RaoOvious (Jun 17, 2013)

Yes,hot DI water washes would suffice until the PH gets neutral.



9kuuby9 said:


> RaoOvious thank you for the answer I really appreciate it



Appreciated.


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## 9kuuby9 (Jun 30, 2013)

Is it possible to recover Pd from a solution using Ammonium Hydroxide and HCl instead of Sodium Chlorate?

Assuming I dissolved Pd using AR and denoxx it from any NO2, and then added a saturated solution of Ammonium Chloride.

Because I can not get my hands on Sodium Chlorate.


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## lazersteve (Jun 30, 2013)

You'll need a chlorine source along with the ammonium chloride to recover the Pd. This can be a chlorate, hypochlorite, or even chlorine gas. 

Steve


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## 9kuuby9 (Jun 30, 2013)

Thank you for the respons Steve.


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## RaoOvious (Jul 1, 2013)

Yes you can.

First make sure that the volume of solution after denoxxing is 10-15 ml/gm,add saturated solution of NH4Cl and then make sure that there are no needle shaped brown crystals of Ammonium tetrachloropalladate.Then add concentrated NH4OH(35%) and let it sit overnight.(You may sometimes need to heat and stir it to get all the Pd convert into tetraammine solution)

Filter the Palladium Tetra-ammine solution,add HCL(PH 2-3) to get purified yellow Palladium Diammine salt.


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## 9kuuby9 (Jul 1, 2013)

Your answer is appreciated as always  

When do you actually know when you have added enough saturated solution of NH4Cl? Would doubling the existing volume with NH4Cl suffice?


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## lazersteve (Jul 1, 2013)

There seams to be a little confusion as to what the contents of your solution are. If you have a dirty starting solution, ammonium hydroxide will precipitate lots of other metals, not just Pd. If your goal is to purify the Pd, this is not the way unless you have a pure palladium solution.

If you are working with a dirty solution, you will need to selectively precipitate the Pd.

Steve


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## Marcel (Jul 1, 2013)

Very informative.
Thanks for sharing!


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## 9kuuby9 (Jul 1, 2013)

lazersteve said:


> You'll need a chlorine source along with the ammonium chloride to recover the Pd. This can be a chlorate, hypochlorite, or even chlorine gas.
> 
> Steve



Would a solution of 14% hypochlorite be able to selectively precipitate Pd as (NH4)2PdCl6?



lazersteve said:


> There seams to be a little confusion as to what the contents of your solution are. If you have a dirty starting solution, ammonium hydroxide will precipitate lots of other metals, not just Pd. If your goal is to purify the Pd, this is not the way unless you have a pure palladium solution.
> 
> If you are working with a dirty solution, you will need to selectively precipitate the Pd.
> 
> Steve



Thank you for clearing that up Steve!


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## lazersteve (Jul 1, 2013)

Hypochlorite reacts with free HCl to form chlorine gas in situ. The higher the chlorite concentration the better, as Pd precipitates best from concentrated solutions.

Calcium Hypochlorite is a dry bleaching powder that will work.

Concentrated bleach (unscented and not color safe) will also work in a pinch.

Steve


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## RaoOvious (Jul 2, 2013)

9kuuby9 said:


> When do you actually know when you have added enough saturated solution of NH4Cl? Would doubling the existing volume with NH4Cl suffice?



It doesn,t work like that.For 1 gram of Pd in solution,prepare 37.1% NH4Cl solution having 1.5 grams of NH4Cl(1.5 times weight of Pd).For example if one has approx. 15 grams of Pd in Solution,then add 22.5 gm(1.5 times Pd) of NH4Cl crystals in approx. 60 ml of water,then pour in into the Pd containing solution.


22.5*100/37.1


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## kadriver (Jul 30, 2013)

I am getting ready to do this experiment in another thread, showing a little more detail, and under the guidance of Rao who has helped me along very graciously.

Here is the beginning of that thread: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=51&t=18907

The Pd black powder I am working with in this thread came from extractions with nitric acid from catalytic converter mixed black PGMs.

I am planning to use a gas generator just like the one in this video to dissolve the Pd black powder - except I'll be using a small gas bubbler instead of a beaker to hold the Pd black powder.

The gas generator in the video uses HCl dripped onto a slurry of trichloroisocyanuric acid (crushed up pool chlorine tablets from the hardware store).

I've used it before and it works perfectly - as long as my fume hood stays running.

[youtube]http://www.youtube.com/watch?v=Iwvt_QHeb7o[/youtube].


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## 9kuuby9 (Jul 31, 2013)

Thx for new post kadriver 

Rao really did help us quite a lot with Pd processing 

Btw has any of you used Al to cement Pd from a nitrate solution? because it takes days before you see some flakes falling down; Or is it because of the extra HNO3?

(The nitrate solution contained some silver nitrate So I separated the salt using HCl to create AgCl, this reaction creates HNO3)


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## kadriver (Jul 31, 2013)

9kuuby9 said:


> Btw has any of you used Al to cement Pd from a nitrate solution? because it takes days before you see some flakes falling down; Or is it because of the extra HNO3?



Hello, I have never used aluminum to cement Pd. 

I am processing some silver cell slimes to try and get a little palladium by cementing on copper.

kadriver


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## samuel-a (Aug 1, 2013)

Al is practcally inert in the presence of NO3-


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## lazersteve (Aug 1, 2013)

Aluminum works great when cementing Pd from chlorine based solutions containing nickel as the primary contaminate (eg: MLCCs dissolved in AP making a Pd + Ni chloride solution), but as Sam alluded, it has no place being used in nitric solutions due to nitric acids passivisation of the Aluminum.

When Al is used for cementing a chloride solution of Pd and Ni, you will achieve a black sediment of Pd and a bright lime green solution of Ni chloride when the cementation is complete.

Steve


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## 9kuuby9 (Aug 1, 2013)

Thx steve!

So Al would be great for cementing Chloride based solutions and even leaving Ni in the solution. (Is their a reason for this? or does Al hate Ni that much ? :mrgreen: )
And Zn would be better in Nitrate based solutions because it does not passivate unlike Al.

A question for steve or anyone who is able to answer it  ; Is it possible to convert Pd nitrate into Pd chloride? Because I really have a hard time getting Zn around here in Belgium.


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## samuel-a (Aug 1, 2013)

It all come down to electronegativity,.
Al does't have enough potential to replace Ni.
Cl- would replace NO3- via simple evaporation to crystallization and adding HCl. 
Search for de-NOx 'ing process


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## mls26cwru (Aug 1, 2013)

9kuuby9 said:


> Thx steve!
> 
> So Al would be great for cementing Chloride based solutions and even leaving Ni in the solution. (Is their a reason for this? or does Al hate Ni that much ? :mrgreen: )
> And Zn would be better in Nitrate based solutions because it does not passivate unlike Al.
> ...



If i am remembering correctly from my chemistry days, Aluminum metal is a bit deceiving... Aluminum has an affinity for oxygen, so all aluminum actually has a 'shell' of aluminum oxide... since the metal is already oxidized, putting it into a strong oxidizer like nitric would have little effect. Hydrochloric on the other-hand is works a bit differently than nitric and will be able to attack the aluminum oxide.

just my two cents.


Mike


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## 9kuuby9 (Aug 1, 2013)

Thx for your input mike!


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## 9kuuby9 (Sep 2, 2013)

RaoOvious said:


> add 1 ml of formic acid for 4 gram of yellow salt or 0.5 ml for 1 gram of Pd metal in yellow salt i.e(1 gram yellow salt contains almost .5 gram of Pd metal)...


What concentration of Formic Acid Should I use in this case? I have 85% of Formic Acid at my disposal.

And thanks again for the help!


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## Lou (Sep 3, 2013)

Don't just use straight formic acid...make it pH 6.5 with caustic and then use it. It's pretty darn quick at reduction so a dosing pump is best.


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## 9kuuby9 (Sep 3, 2013)

Lou said:


> Don't just use straight formic acid...make it pH 6.5 with caustic and then use it. It's pretty darn quick at reduction so a dosing pump is best.



From the description you'll have to add to the Yellow diammine salt; a certain amount of distilled water and Formic acid are added And then 25% NaOH is added in increments?

I guess everyone has his way of processing Pd :mrgreen: 



RaoOvious said:


> Add DI water(Approx. 20 ml for 1 gram of Palladium or 10 ml for 1 gram of yellow salt) to Yellow diammine salt,then add 1 ml of formic acid for 4 gram of yellow salt or 0.5 ml for 1 gram of Pd metal in yellow salt i.e(1 gram yellow salt contains almost .5 gram of Pd metal),heat them upto to 65 C,then slowly add 6.25 M(25% NaOH solution or 250 grams NaOH per litre of water) NaOH solution such as for 1 gram metal or 2 gram yellow salt 1.7 ml of 6.25 M NaOH should be added.Suddenly after some greenish look all the yellow metal would be converted into beautiful settling Pd sponge.



Thanks Lou!


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## RaoOvious (Sep 22, 2013)

9kuuby9 said:


> What concentration of Formic Acid Should I use in this case? I have 85% of Formic Acid at my disposal.



Its fine,just observe the volumes to be added as per precious grams in salt.

One aspect is dont put all the acid at once,just give it a little sip,and when temp gets to 65 C,then add the rest & finally 25% NaOH to enhance the PH to drop it like a grain completely.



9kuuby9 said:


> I guess everyone has his was of processing Pd



Its the same thing in essence at the end,so do it and then get satisfied as to which to put first  

I saw your query today.

Good Luck


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## 9kuuby9 (Sep 22, 2013)

Thank you for the detailed explenation! As it was, is and will be quite a journey :mrgreen:


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## Research135 (Aug 9, 2015)

Lou said:


> You can O2/H2 melt the material and it will look shiny but it cannot be made into a casting. *Have learned this the hard way*.
> 
> It can only be vacuum melted and doing that from the sponge is a difficult proposition, as most induction melters' work coil frequencies are too low to melt anything less than bulk metal. You can do it if your customer starts with a heel made from the pure metal or alloy thereof.


Everything was going well for these guys... till they attempted to pour an ingot. Look at that thing spit and swell!.

edit: No safety goggles, no thermal clothes, no understanding, no respect... good electronics, I guess.

https://www.youtube.com/watch?v=r9sTVx_YV5A


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## Research135 (Aug 9, 2015)

Rao: The pictures of the processes are beautiful. And the palladium sand dropped with formate is what I've always aspired to get.

Can you see the pros and cons of just applying the sodium formate to the initial dark solution? (I understand you apply the formic acid first and then the sodium hidroxide).
I'm guessing that you are reaching for higher purity, as it purports in the books and pamphlets. The books sometimes deceive, and the pamphlets more. Try a small experiment and be amazed. Two iterations of what I've just written, and no need for ammonia, etc, handling of poisonous salts, etc, etc, etc.

In other words drop the metal from initial concentrated solution using sodium formate at pH little less than 7, temperature little less than 100 degC, wash the precipitate with DI water, re-dissolve with HCl-Cl2 or other method that avoids de-noxxing, filter (little to filter), drop again with formate, wash sponge with water. Only two beakers needed, and no handling of solid salts. 999, and sometimes 9999 product. Leave the ammonia and its salts for someone else. For ultimate purity, with a lot of work, DMG instead of second formate drop, washing the DMG compound (cumbersome), and conversion of same with... sodium formate, again.

edit: Of course I'm assuming there is no gold or platinum in your initial liquid. 
edit2: Also I'm assuming that the initial solution is brought to around pH 6 and filtered, before the first formate drop.


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## Lou (Aug 9, 2015)

Keep in mind that Pd precipitates round pH 6.


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