• Refining Palladium concentrates.

Some pictures on Refining Palladium concentrates.

I used the outlined process provided by our fellow member of the forum "4metals"
(additional steps that are marked with "***" and start with "▪" are not from the original steps but are additional steps that may improve this process)

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=51&t=6638&start=20#p72403

let's start with the first three steps;

▪ Calculate and add, stoichiometrically half of the needed amount to dissolve Palladium and add the remaining half in increments, cease addition when no more reaction occurs. It's not easy to Dennoxx a nitrate solution without HCl.***

• Digest the impure palladium metal in 50% nitric / distilled water.

▪ Evaporate solution down to 10ml-15ml of solution per gram of Palladium.***

• Raise the pH to anywhere between 1 and 2 with NH4OH

▪ Evaporate solution down to 10ml-15ml of solution per gram of Palladium.***

• Filter the solution to remove any turbidity or sediment, which may be AgCl.

Continuing with the forth step until the eighth step

• Take a volume of solution equivalent to 500 grams of palladium.

• While stirring add NH4OH to a pH of 10 (Expect to add at least 1500 ml of NH4OH) Any Iron or Nickel will precipitate.

• Filter the solution of any turbidity or sediment.

• Acidify with HCl to pH 6.5 to 7. At this pH any AgCl will come out of solution.

• Filter the solution to remove any sediment.

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The blue color shows presence of base metals ammine complexes like [Ni(NH3)6],[Cu(NH3)4] and [Cu(NH3)4(OH)2]

Continuing with the ninth step.

• Continue to acidify with HCl to a pH of 3 where the precipitation of Palladium is essentially complete.

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Still Continuing with the ninth step.

• Continue to acidify with HCl to a pH of 3 where the precipitation of Palladium is essentially complete.

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*Still Continuing with the ninth step.

• Continue to acidify with HCl to a pH of 3 where the precipitation of Palladium is essentially complete.







Is it normal that the solution starts to react (bubble) after the salt has fully setteld?
a plausible reason;This might be due to excess HNO3 or NH4NO3 reacting with some excess HCl.

I've placed the beaker containing solution on a hot plate; to stir and heat the solution to drive any excess NOx away. The reason behind this is because the salt might be soluble in AR and thus if directly filtered, some of the salt might have been dissolved in the solution.

9kuuby9 said:

Some pictures on Refining Palladium concentrates.

I used the outlined process provided by our fellow member of the forum "4metals"
(additional steps that are marked with "***" and start with "▪" are not from the original steps but are additional steps that may improve this process)

http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=51&t=6638&start=20#p72403
(big snip)

Click to expand...

Thank you for the detailed breakdown of 4metals process. Are you going to show the process to completion ???
Visual aids are worth a thousand words when describing what reactions to look for and see in a process.
The visual references of the changes involved in the process are now very clear in my mind of what to look for when I try some similar material early this coming spring.

niteliteone said:

Thank you for the detailed breakdown of 4metals process. Are you going to show the process to completion ???
Visual aids are worth a thousand words when describing what reactions to look for and see in a process.
The visual references of the changes involved in the process are now very clear in my mind of what to look for when I try some similar material early this coming spring.

Click to expand...

You're welcome and I'm glad you liked it :mrgreen:

I'm still working out this process as we speak, It should be done in a few days.

I also will put up a photosensitive guide for processing Silver from silver Chloride in a particular way, when palladium is the main contaminate without using DMG.

Which should give you 999+ Silver when used correctly, and also it's very important to work in a clean and neat manner this also increases the purity greatly 8)

Hi 9kuuby9,
looks like you are doing very well,
I need to do much more reading ,learning before I get to that level
I'll stay with my ram fingers, chips and collecting stuff for some time.
But very nice post and very nice pictures, well explained and I am sure I will look for this post
when I am ready to get the palladium out of my e scrap.
Love the clear colors of the solutions

Take care and keep up the good work

Pat

Thanks Pat for your support and encouragement! :mrgreen:

I hope you're doing well too?

Kind regards,

Ben

Continuing with the tenth step.

• Cool the batch and decant or pump off the liquid. Slurry the precipitate to a buchner funnel and rinse with a rinse liquid made with 10 ml of HCl per liter of DI water.

Continuing with the eleventh step.

• Place all liquors into reclaim as there are always values which should be cemented and collected.

an Additional step for a higher purity, take notice of the color of the solution;

▪ Combine Diammine salts and redissolve in excess aqueous NH3 and re-precipitate by ajusting the Ph to 1.5-3.***

Hi 9kuuby9,

Thanks for sharing your progresses and pictures of beautyfully colored Pd-solutions. They remember me my earlyer, most active Pd-refining times. Because I was involved intensively and quite a lot of time in these processes, please let me add a few comments.

• Filter the solution to remove any turbidity or sediment, which may be AgCl.

Click to expand...

I wonder, where significant quantities of silver should come from. In my practice I never found silver (not even traces) in the raw-Pd-feedstock to be refined to 4-nine-Pd.

• While stirring add NH₄OH to a pH of 10 (Expect to add at least 1500 ml of NH₄OH) Any Iron or Nickel will precipitate.

Click to expand...

I prefer the formula NH₃ for aqueous ammonia, despite the evidently still quite popular, but false expression NH₄OH for a non-existing compound ammonium hydroxide. Under the conditions of this step Ni will remain in solution as the blue hexammine-nickel(II) complex-ion, [Ni(NH₃)₆]²⁺, together with Cu(II), presumably as dark blue [Cu(NH₃)₄]²⁺, like shown in your pictures.

Is it normal that the solution starts to react (bubble) after the salt has fully setteld?
a plausible reason;This might be due to excess HNO₃ or NH₄NO₃ reacting with some excess HCl.

Click to expand...

I think, it is normal, because the dissolution of Pd in nitric acid seems to me to be a quite complex process. It is especially one observation, which intrigued me quite soon: the only very sparingly evolving NO_x in the digestion process, very different from NO_x-evolution in the digestion of PM's in AR, Pd included. This difference became even more evident on digesting finely divided Pd (Pd-black) in aqueous sulfuric acid mixtures, containing HNO₃ only in amounts sufficient to oxidize metallic Pd to Pd(II) quantitatively, assuming quantitative reduction of N(V) in HNO₃ to N(III) in HNO₂. 100 g batches of Pd-black dissolved in about 1 hour completely in appropriate acid-mixtures, without evolution of thick NO_x-clouds. Apparently reduction-products of nitric acid are/remain bound to a central Pd(II)-ion, and the resulting complexes are quite stable, even on strong heating. A lot of Pd(II)-complexes with nitrite (NO₂^-) are known. They are stable under neutral conditions, but decomposed more or less rapidly by aqueous hydrohalic acid (HCl, HBr, HJ), forming the corresponding halide-complexes, together with NO_x.

9kubby9,

You are going great and on the right track.The second dissolution of Palladosomine showing a transparent color with yellowish tint shows it all.Keep it up and well done.

Rao

Well first of all I would like to thank you all for the support and encouragement!

And also for the kind help everyone provided me here on the forum.

Especially freechemist & RaoOvious :mrgreen:

I always get to learn something new when freechemist comments on something 8)

And The final results are coming in a few minutes.

Continuing with the last half of the process.

• Slurry the salt with 1000 ml of DI water into a heat-able vessel and add 9000 ml additional DI water.

• Add 100 ml HCl and 250 ml formic acid



• Heat solution to 65 C

• Slowly add 850 ml of 6.25N NaOH maintaining the temperature at 65-70 C

• Reduction is complete when the Pd drops to the bottom the solution becomes colorless and the pH will be between 7 – 8. some recoverable Pd remains in the liquids so save the liquids as before for cementation.



-Notice the bubbling; most likely a catalytic reaction.

I am sure I say what everybody thinks, when I am saying that together with 4metals description this pictured guide will be a great help for us newbs when doing our First Time Palladium and it is a great motivation! Thank you very much!

Nice posts!