What else in AP besides CuCl?

[solar_plasma]

AP actually reduces Pd into PdCl2

Just for correctness...it is oxidizing...the loss of electrons is an oxidation, the gain of electrons is a reduction.

Can you redissolve the powder? While dissolved, is the solution brown? Does dmg form a lot of fale yellow precipitate? Does SnCl₂ make green colour that changes to brown?

I understood, the dissolved metal ball made a blue solution, but Pd should make a brown solution.

 

[Alentia]

The brown powder is contaminated with copper and possibly some other chlorides. When melting under oxygen most of Pd spread around the dish or flew. So I could only get small amount of Pd into the tiny ball.

Stannous test produced green color on contact with test paper dipped into the solution.

It seems dissolving PdCl2 in HCl require constant heating for several hours, which I did not perform. That would explain, my statement, that it does not dissolve in any of the acids.

I am somewhat confused on how to recover Pd from PdCl2. The reaction posted on wiki is PdCl2+CO+H2O -> Pd+CO2+2HCl. That is bubbling Carbon Monoxide through.

While I caclinated small amount of it in wood burning stove, there is good chance I had reduced some of the Pd chloride into metallic form, when heating it inside.

 

[solar_plasma]

While I caclinated small amount of it in wood burning stove, there is good chance I had reduced some of the Pd chloride into metallic form, when heating it inside.

PdCl₂ sublimates at 590°C, it is volatile.

 

[butcher]

Alentia,
I do not see this reaction you wrote working.
Pd + 2 CuCl2 → 2 CuCl + PdCl2

Palladium is lower in the reactivity series than copper.

With that in mind I can see this reaction working:
PdCl2 + Cu --> CuCl2 + Pd

Although Palladium will go into solution of HCl, and so it is possible to have some PdCl2 mixed in solution with your CuCl2 solution, copper metal will replace palladium from solution, so as the CuCl2 solution reacts to dissolve more copper the palladium will cement out of solution before CuCl forms.

This brown powder you are speaking of Has it been rinsed in water? CuCl in concentrations can also be a brown powder, when rinsed with water it will change to a white powder, as some of the concentrated solution forms some CuCl2 in the rinse.

If I had PdCl2 I would not heat it or incinerate the powders unless I wished to make a hard to dissolve palladium oxide, (Read Hokes book to learn more about this), if you did have CuCl and palladium chloride in the powders a solution to recover the palladium is to rejuvenate the CuCl back into CuCl2 and cement palladium with copper.

If you did have palladium and you roasted it you would likely now have palladium oxide which would be hard to dissolve again, See Hokes book.

 

[Alentia]

Alentia,
I do not see this reaction you wrote working.
Pd + 2 CuCl2 → 2 CuCl + PdCl2

Palladium is lower in the reactivity series than copper.

With that in mind I can see this reaction working:
PdCl2 + Cu --> CuCl2 + Pd

Although Palladium will go into solution of HCl, and so it is possible to have some PdCl2 mixed in solution with your CuCl2 solution, copper metal will replace palladium from solution, so as the CuCl2 solution reacts to dissolve more copper the palladium will cement out of solution before CuCl forms.

This brown powder you are speaking of Has it been rinsed in water? CuCl in concentrations can also be a brown powder, when rinsed with water it will change to a white powder, as some of the concentrated solution forms some CuCl2 in the rinse.

If I had PdCl2 I would not heat it or incinerate the powders unless I wished to make a hard to dissolve palladium oxide, (Read Hokes book to learn more about this), if you did have CuCl and palladium chloride in the powders a solution to recover the palladium is to rejuvenate the CuCl back into CuCl2 and cement palladium with copper.

If you did have palladium and you roasted it you would likely now have palladium oxide which would be hard to dissolve again, See Hokes book.

Thank you, Butcher, good suggestions "go back to the source"! It does not matter how many time one re-read Hoke, you have to go back for more.

As for the reaction, it is described in Wikipedia, which might be incorrect. http://en.wikipedia.org/wiki/Copper(II)_chloride

However it suggests treating PdCl2 with ethylene and water to reduce to metal form.

A major industrial application for copper(II) chloride is as a co-catalyst with palladium(II) chloride in the Wacker process. In this process, ethene (ethylene) is converted to ethanal (acetaldehyde) using water and air. During the reaction, PdCl2 is reduced to Pd, and the CuCl2 serves to re-oxidize this back to PdCl2. Air can then oxidize the resultant CuCl back to CuCl2, completing the cycle.
C2H4 + PdCl2 + H2O → CH3CHO + Pd + 2 HCl
Pd + 2 CuCl2 → 2 CuCl + PdCl2
4 CuCl + 4 HCl + O2 → 4 CuCl2 + 2 H2O

 

[FrugalRefiner]

When I see someone relying on Wikipedia I am always reminded of an episode of The Big Bang Theory in which Raj's research has failed. When asked what he's been doing with his time, he replies "mostly checking e-mail, updating my facebook status, and messing up Wikipedia entries".

It's good to remember that according to Wikipedia, "Work submitted to Wikipedia can be edited, used, and redistributed—by anyone—subject to certain terms and conditions."

Dave

 

[Alentia]

When I see someone relying on Wikipedia I am always reminded of an episode of The Big Bang Theory in which Raj's research has failed. When asked what he's been doing with his time, he replies "mostly checking e-mail, updating my facebook status, and messing up Wikipedia entries".

It's good to remember that according to Wikipedia, "Work submitted to Wikipedia can be edited, used, and redistributed—by anyone—subject to certain terms and conditions."

Dave

Well, the same reaction is described in the book http://books.google.ca/books?id=4X_...&ved=0CGQQ6AEwBw#v=onepage&q=Pd+CuCl2&f=false

by Jiro Tsuji "Palladium Reagents and Catalists"

I have once edited Wikipedia article... My edit was revised within 10 min of posting.

 

[Platdigger]

Interesting. So, if this is correct, CuCl2 will put pd into solute.
Or perhaps it is only in the presence of these other chemicals.

 

[Alentia]

Interesting. So, if this is correct, CuCl2 will put pd into solute.
Or perhaps it is only in the presence of these other chemicals.

It will and than it should spit it out when CuCl is present, not sure if I am correct, but I believe PdCl2 should precipitate before CuCl does.

Than, when we wash foils with HCl it will most likely redissolve and go to waste.

 

[butcher]

Alentia,

I cannot comment on the catalytic reactions you posted, they are dealing with organic chemistry that is just over my head, at this time.

I would be careful with the platinum group metals and organics, you could easily end up burning the lab down, by some unintended catalytic reaction.

 

[Alentia]

Alentia,

I cannot comment on the catalytic reactions you posted, they are dealing with organic chemistry that is just over my head, at this time.

I would be careful with the platinum group metals and organics, you could easily end up burning the lab down, by some unintended catalytic reaction.

Leaving C2H4 aside, I guess this should debunk the myth that AP does not attack any precious metals. In the processes described above 3 separate reactions are happening, while they are relevant for Wacker process, they can happen independently:

1. Conversion of ethylene with source material being PdCl2, which reduced by the reaction (learned from SP ) - only relevant as a way to reduce PdCl2 to metallic form.
2. Re-oxydation of Pd to PdCl2 with CuCl2 - this can be viewed as standalone reaction. Even though Cu is higher, there is some kind of lazersteve's magic in it to dissolve lots of things.
3. Rejuvenation of CuCl2 with Oxygen, we all know about.

 

[Geo]

Of coarse AP solution will dissolve palladium. Anyone that has had to work with it day in and day out takes it for granted that others should have the same insight. I caught this thread in the middle but would like to add something. When we speak of AP, I assume we are all referring to copper chloride leaching of base metals. During the leaching process, most all metals are susceptible to attack by the etchant in the presence of free oxygen. As long as copper is available, it is nearly impossible to dissolve a lower reactive metal. It is only at the beginning or at the very end of the process that the lower reactive metals will dissolve. This is due to the lack of available copper for the etchant to attack. The more copper a solution absorbs, the less of any other lower reactive metal it can hold. If you are concerned whether or not your AP solution is holding values, it is simple enough to remedy. Simply add more copper. The more reactive to copper the solution becomes, the faster the values will cement out of solution.

 

[Alentia]

Geo,

Thank you for your input.

However it seems the case with Pd is not a redox reaction, where Pd will remain oxidized in the form of grey mud at the bottom of the vessel.

I am yet to try heating "grey mud" in diluted HCl for several hours to see if it can be all dissolved.

If PdCl2 dissolved in CuCl2 solution, I expect stannous test to show nothing as there is no reaction, am I correct?

 

[Geo]

i have processed a lot of whole boards in AP and have dealt with the grey sludge many times. as best as i can determine, it consist mostly of tin oxide. its not the same composition as metastannic acid which is produced by dissolving tin in nitric acid but it is produced by another route. tin in AP is converted to stannous chloride, by the very process of adding oxygen to the solution to aid in the etching, it also converts the stannous chloride to tin oxide. even though metastannic acid is a form of tin oxide (hydrated tin oxide), the tin oxide created by AP is different (texture,consistency). tin oxide is insoluble in most acids and is the scourge of the hobbyist refiner. it cant be calcined, but by incinerating the grey sludge, the tin oxide is converted through a couple of different phases back to elemental tin and can be removed in a hot hcl wash.

remember, theres tin in components other than solder. any electrical contact that is made to be compressed like a spring (slot connector pins) is phosphor bronze. bronze is copper+tin where brass is copper+zinc.

 

[stefano]

Old topic, but same problem.

For the moment i have the same problem with palladium chloride solution mixed with copper(II)chloride solution. I recovered the palladium from very tiny mixed components of cellphone boards, which i leached with HCl/H2O2 like lazersteves process. I eliminated the silver chloride and tried to cement the palladium with pure copper. Almost nothing happened after six hours.
Then i cemented all with aluminium foils. All precipitated and the solution was clear, had a color of nickel chloride and was negative on sc-test.
I washed the precipitated powder many times with water. Then i tried to dissolve the copper in the powder with CuCl2-solution, which was absolutely free of H2O2. I added the CuCl2-solution to the powder, and in the following days i stirred often to mix the solution with the powders and to introduce air for regenerating the solution.
After a couple of days i let completly settle the powders and then i did a sc-test. The test showed very much palladium in the solution. Q-tip was dark black and turned then green after a few minutes. This means that palladium powder will dissolve in CuCl2-solution. At me it seeems very difficult to precipitate palladium from these type of solution mix with copper.

Geo described in this topic the trick, but at me it did not work. Where failed i ?

 

[g_axelsson]

CuCl2 with HCl dissolves palladium.
It's a step in the Wacker process.
https://en.wikipedia.org/wiki/Wacker_process

Göran

 

[stefano]

I think too that the Wacker process is well proved. I do not try anymore to cement palladium from a mix of palladium chloride solution and copper chloride solution.
For the mix that i have in the moment i am repeating the cementation with aluminium. Then i want to clean the powder very well from chlorides without incineration. Then i want to dissolve all in dilute nitric, and then cementing on copper. That seems no problem to me.

But what shall i ( and we all ) do with the copper chloride solution stockpot which contains a lot ( very lot ) of copper and palladium chloride mixed with it. How can we get out the palladium without all the named above problems ?

 

[g_axelsson]

If you have excessive metallic copper in your stock pot then the palladium should cement onto that and CuCl2 will be turned into CuCl. In theory at least.

If you have any less noble metal, for example iron, in the stock pot then the copper will cement with the palladium and other values until the metal is exhausted.

To run the stock pot until all base metal is dissolved is not advised.

Göran

 

[Barren Realms 007]

Adjust your PH of your solution up to around 2-3 and see if your Pd will cement out then.