# What else in AP besides CuCl?



## Alentia (Jan 19, 2014)

After processing months of computer scrap in AP I end up with foils and grey mud in the bucket. I bet everyone is familiar with the picture.

After washing with HCl, some of the mud dissolved in the HCl, but some remained. I have dried 2 batches, one batch I have treated with H2SO4 (about 5ml) and piece of iron (5gr).

After I have it dried, I had evaporated chloride on slow heat inside oven and received light brown (copper like) powder.

The said powder does not dissolve in HCl, HNO3 nor AR. It melts into small balls at high temp in the dish with torch. Balls do not join together in melting dish but scattering around the dish. What is this material? I did not try to heat AR yet. The yellow liquid in the tube tests "clear" with stannous.

Got pictures in wrong order...


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## solar_plasma (Jan 20, 2014)

I would bet on iron.

Butcher wrote:


> ferric chloride will form insoluble iron oxides and hydroxides (especially when heated) which are insoluble yellow or red powders, which are very resistant to acids even aqua regia


 http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=48&t=7674#p121562


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## nickvc (Jan 20, 2014)

Alentia may I first say I'm no expert on the AP method but I know what I would do with this powder. The sediment you recovered from your AP was from numerous items I'm guessing so there is a good chance that you have a mix of elements in your powders. I'd wash the powder in boiling water several times then dry and incinerate the powders. Then I would give the powder a good wash in hot hydrochloric acid and repeat until no colour comes from the powder and then dissolve in hydrochloric and bleach. Filter and precipitate, testing all solutions for any values obviously as I go. The gold powder may well not be clean so if high quality is your aim I'd then redissolve in AR and precipitate again
The used filters could ontain values depending on the feed you used so keep and process when the quantity warrants the time or effort.
You could also try washing the powder in hot hydrochloric first but I'd still be tempted to incinerate it whichever method you choose.


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## solar_plasma (Jan 20, 2014)

...I should add, I meant the brown powder, which didn't dissolve at all or in anything.


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## Alentia (Jan 20, 2014)

nickvc said:


> Alentia may I first say I'm no expert on the AP method but I know what I would do with this powder. The sediment you recovered from your AP was from numerous items I'm guessing so there is a good chance that you have a mix of elements in your powders. I'd wash the powder in boiling water several times then dry and incinerate the powders. Then I would give the powder a good wash in hot hydrochloric acid and repeat until no colour comes from the powder and then dissolve in hydrochloric and bleach. Filter and precipitate, testing all solutions for any values obviously as I go. The gold powder may well not be clean so if high quality is your aim I'd then redissolve in AR and precipitate again
> The used filters could ontain values depending on the feed you used so keep and process when the quantity warrants the time or effort.
> You could also try washing the powder in hot hydrochloric first but I'd still be tempted to incinerate it whichever method you choose.



Nick,

That is exactly what has been done resulting in brown powder not soluble in AR and therefore will not be soluble in Chlorine.

Solar,

Good call, I will test with magnet small melted piece and will advise. However, I am not fully understand how Iron Chloride would precipitate in AP as grey mud as it should be absorbed by the solution and be removed during washes.


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## nickvc (Jan 20, 2014)

Sorry you didn't mention using heated solutions or incineration some don't do either but both will help in ridding the powder of base metals and with filtering later.


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## butcher (Jan 20, 2014)

There are some metals like tin and Iron that their chemistry can get very complicated.
Iron being one of those metals that its chemistry can be complicated iron can be oxidized into many different oxidation states, even when made int a metal salt by dissolving it in acids it can many hold several different oxidation states of that one metal-acid salts.

Iron chlorides a metal-salt formed with Iron and HCl, can have a two main oxidation states, FeCl2 and FeCl3, (both soluble in solution), but even these can be easily converted to other oxidation states of iron depending on conditions, they can form iron oxides or hydroxides depending on conditions, another thing with solutions we can push iron out of solution with metals higher in the electrolytic series of metals higher in series than iron.

Strongly heated iron salts in solution with water can hydrolyze, and become hydroxides of iron which are insoluble, this can also happen easier if pH of the iron solutions are not very acidic or are changed with bases such as NaOH or other basic solutions...

Most of the different iron salts, when the soluble iron salts are evaporated to crystals and dried can easily be oxidized by air or oxygen, especially if the are not kept acidic, and are exposed to oxygen over time, like the pretty green crystals of ferrous sulfate can oxidize to brown and white iron oxides, heating copperas crystals with a torch in a melting dish would drive off the SO2 gases and oxidize the iron to an iron oxide dust from the oxygen in the environment and or from the torch. 

Iron has many oxidization states:
Compounds of iron:
http://en.wikipedia.org/wiki/Category:Iron_compounds

http://en.wikipedia.org/wiki/Category:Iron_oxide_pigments


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## Alentia (Jan 20, 2014)

butcher said:


> There are some metals like tin and Iron that their chemistry can get very complicated.
> Iron being one of those metals that its chemistry can be complicated iron can be oxidized into many different oxidation states, even when made int a metal salt by dissolving it in acids it can many hold several different oxidation states of that one metal-acid salts.
> 
> Iron chlorides a metal-salt formed with Iron and HCl, can have a two main oxidation states, FeCl2 and FeCl3, (both soluble in solution), but even these can be easily converted to other oxidation states of iron depending on conditions, they can form iron oxides or hydroxides depending on conditions, another thing with solutions we can push iron out of solution with metals higher in the electrolytic series of metals higher in series than iron.
> ...



Tested melted ball - it is not magnetic.


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## solar_plasma (Jan 20, 2014)

Is the ball metallic? I never tried, but I don't believe that all iron oxides are magnetic.


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## Alentia (Jan 20, 2014)

solar_plasma said:


> Is the ball metallic? I never tried, but I don't believe that all iron oxides are magnetic.



Yeah, that is the one on 3rd picture. Any oxide will convert to elemental metal on melting.


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## solar_plasma (Jan 20, 2014)

That is not true for all oxides and thats even not true for all metal oxides.


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## butcher (Jan 20, 2014)

Iron can form oxides that are non magnetic.
Many iron oxide powders could be hard to melt back into iron metal, in fact it is easier to make a slag of iron when melting than it is to melt many iron compounds back into metallic iron.

Iron oxidizes easily at its melting point, when they make iron they need a carbon source like coke or coal and usually use lime in the flux, to convert the oxides to CO2 gas, and they melt in furnaces that help keep oxygen out of the mix.


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## SCB (Jan 21, 2014)

butcher said:


> ... and they melt in furnaces that help keep oxygen out of the mix.



Well.. Slight OT but oxygen is a crucial part of both iron and steelmaking.
Oxygen is bubbled through the molten iron/steel to lower the content of some alloying elements such as C and Si. It’s a violent reaction and the molten steel boils vigorously from the CO/CO2 formed, but as long as there are carbon left in the charge very little Fe will be oxidized.
Making oxides from the iron is not a big deal, it’s quite easy to push it back into metallic form again. It's just a matter of adjusting the chemical composition of the slag depending on what one wants to do. Putting elements in the slag and later recovering them from the slag is standard procedure in refining steel.


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## solar_plasma (Jan 21, 2014)

For example Fe2O3 will *melt *at 1565 °C, it will not *decompose*. Maybe the reducing zone of the torch would reduce the iron if temps are high enough, but that is something else: It doesn't turn to metal because of it melts, but because there is a reducer present, probably CO. And if it is correct what my dad once has tried to teach his youngest son about welding, it will work for the skilled welder.

Still I believe you have made some non-magnetic iron ceramic. I do only see brown slag...is it metallic inside, is it conducting electricity, is it dense and is it thermoconductive? If all four are positive, then I believe you have a non-magnetic metal.


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## Alentia (Jan 23, 2014)

The metal ball dissolved in HNO3. Judging by the color traces of copper are present.

Based on stannous and DMG test traces of Pd (white precipitate) and Pt (orange) are present.

Presence of Pt is kind of strange. Stannous reacts with orange color. I wonder if Pt behaves the same when alloyed with silver (dissolves in HNO3) when alloyed in small percentage with copper and Pd.

It is possible my initial comment was misread. After drying the "mud" I had it calcinated (removed chlorine) in the oven to arrive to the brown powder.

No presence of silver, iron or nickel was identified.


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## Pantherlikher (Jan 23, 2014)

Greetings...
First the novice question.
Would well used or "spent" AP push iron out of solution as suggested? 
Being a novice, I'd think iron would push copper out. This would remove tin, iron, and others from solids? Leaving everything above as solids.

Ok... Everything and anything goes into the AP so it will have anything.
Incinerate and wash with water, then hot HCL.<(some Sulphuric added here?)
Incinerate again.
Here, I would think to use HCL and a few drops of AP solution. Enough to get the AP running again which would rid alot more base metal if here right? HCL and some peroxide would dissolve alot as an oxidiser is added. Would this be the same as adding alittle AP solution?

Then incinerate again and warm nitric with some sulphuric for any lead? Not sure where to add Sulphuric for any lead but think in early step with hot HCL.

Would this rid the solids of any iron and other base metals? 

If so, then AR, filter and test/ drop.
Any solids not dissolved from this should go to AR with hard boil if I'm keeping my steps straight.
Testing along the way to catch PMs as they dissolve.

I need to reread Hoke to get it all straight, but I believe you would want to incinerate between steps while dissolving/ removing base metals followed by the PMs untill you run out of solids.

As a side thought being Novice in the soupy mess. Would using poor man's nitric acid, (Sodium nitrate + sulphuric) play any role in breaking down any complex metals to rid from solids? How about poor man's AR?
Wondering here if different combinations of acids react differently.

B.S.
...Let the learning chastization begin here...


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## solar_plasma (Jan 23, 2014)

@altentia
Maybe I did misunderstand you, since I understood the powder would not dissolve in anything and I believed you had tested the liquids above the solids after each acid treatment.


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## Alentia (Jan 23, 2014)

solar_plasma said:


> @altentia
> Maybe I did misunderstand you, since I understood the powder would not dissolve in anything and I believed you had tested the liquids above the solids after each acid treatment.



Yes, that is correct. The powder (brown powder) would not dissolve in anything. The brown powder was a result of caclinating grey mud after it was washed several times with HCL and water afterwards.

Once I have melted the brown powder, I was able to create few small metallic non magnetic balls. Obviously I was very confused when everyone suggested it was non magnetic iron, and I still am.

Melting was very annoying as small balls were very stubborn not willing to join into single ball.

One of the balls easily dissolved in HNO3 resulting in the liquid I have posted test results for.

I am assuming I have lost percentage of Pd while melting with oxygen in open dish.

I am more concerned about how to process mud in the future, since calcinate will not dissolve in anything. Well, I did not try alkali.

I can collect brown powder for later Pd recovery, but I do not have equipment to properly melt it and assay to even understand if it's worth it.


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## Alentia (Jan 23, 2014)

Pantherlikher said:


> Greetings...
> First the novice question.
> Would well used or "spent" AP push iron out of solution as suggested?
> Being a novice, I'd think iron would push copper out. This would remove tin, iron, and others from solids? Leaving everything above as solids.
> ...



Panther,

I think you are correct on first paragraph. 

But the rest is not so easy.

I have incinerated the mud once and resulting powder will not dissolve in anything. So that would stop your process right there.


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## Alentia (Feb 12, 2014)

I think I have an answer to my question and the brown powder I had created.

Pd + 2 CuCl2 → 2 CuCl + PdCl2

Brown powder is PdCl2.

I might have missed a mention anywhere on the forum that AP actually reduces Pd into PdCl2. I was always under impression that Pd settles in AP in metallic form.

I was always wondering what is happening with Pd from MLCC on boards.

Trying to melt brown powder was/is bad idea. It was not alot and it was for discovery anyway.


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## solar_plasma (Feb 12, 2014)

> 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.


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## Alentia (Feb 12, 2014)

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.


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## solar_plasma (Feb 12, 2014)

> 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.


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## butcher (Feb 12, 2014)

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.


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## Alentia (Feb 12, 2014)

butcher said:


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



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_


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## FrugalRefiner (Feb 12, 2014)

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


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## Alentia (Feb 12, 2014)

FrugalRefiner said:


> 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.


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## Platdigger (Feb 12, 2014)

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


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## Alentia (Feb 12, 2014)

Platdigger said:


> 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.


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## butcher (Feb 13, 2014)

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.


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## Alentia (Feb 13, 2014)

butcher said:


> 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.


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## Geo (Feb 13, 2014)

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.


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## Alentia (Feb 13, 2014)

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?


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## Geo (Feb 13, 2014)

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.


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## stefano (Jun 23, 2016)

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 ?


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## g_axelsson (Jun 23, 2016)

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

Göran


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## stefano (Jun 23, 2016)

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 ?


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## g_axelsson (Jun 23, 2016)

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


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## Barren Realms 007 (Jun 23, 2016)

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


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