Cementing palladium with copper

[Wonka]

I have read of a different way to drop platinum. I’m in the middle of the process so I’m not sure of its effectiveness., but use ammonium chloride to saturate the solution then add hcl slowly. This causes the platinum salts to break down to pure platinum metal. Then dump the metal in AR to get rid of any impurities. It looks like it’s working so far but I’ll have to wait tell it’s tested for the results.

I believe this process will work for paladdium aswell.

 

[Wonka]

Here’s the process of which I speak. Just replace platinum with pladdium.

 

[Alondro]

The Chlorine is to make sure the Pd salt has the correct valence.
You can use Sodium Chlorate in stead.
Then drop with either KCl or NH₄Cl not Ammonia
And it should work well in Palladium Nitrate
The resulting salt can be calcined but if you are not careful you will have losses.

Have you read Hokes version on reduction with Formic acid?
It is very complete and fast, no risk of losses.

I'd need some way to properly monitor the pH. I suppose a digital pH reader will be accurate enough for this. It only needs to be 'mostly' accurate.

 

[Yggdrasil]

Here’s the process of which I speak. Just replace platinum with pladdium.

Please get your names of elements and chemicals correct.
It is:
Platinum and
Palladium (From the Greek Goddess Pallas Athene)

 

[Yggdrasil]

Here’s the process of which I speak. Just replace platinum with pladdium.

Do you have pure H2 gas to reduce it?
It needs to be done under strictly controlled conditions.
Read Raleigh Gilchrist for this.

 

[kurtak]

Finally i think i will buy DMG.
Thank you very much.

First - did you read the thread I provided a link to - if so then in that thread it showed two methods

1) using a solid copper bar with bubbler for agitation

2) using FINE copper powder with GOOD stirring

From my personal experience - when cementing Pd (or PGMs) with copper you are far better served using the copper powder method rather then the copper bar method

So if you still decide to cement with copper & you need more info about doing the copper powder method I can help you with that

That said- DMG will certainly work - have you ever used it before - if not ask & we can help

About how much Pd do you think you have in solution ?

What i hate with DMG is that it's not easy to get back to Pd metal...except it you burn it, but then you have some loss...

Calcining it (burning it) is one why to reduce the DMG/Pd salt - another way is to use ion exchange with zinc & HCL --- kind of like using iron & sulfuric to reduce silver chloride

Those are the more simple methods for reduction --- other chemical reduction method of course also work but more tricky

Kurt

 

[Golddigger76]

I have read of a different way to drop platinum. I’m in the middle of the process so I’m not sure of its effectiveness., but use ammonium chloride to saturate the solution then add hcl slowly while heating at 80-100C. This causes the platinum salts to break down to pure platinum metal. Then dump the metal in AR to get rid of any impurities. It looks like it’s working so far but I’ll have to wait tell it’s tested for the results.

The OP was needing to get Palladium separated from solution not platinum

 

[100tific]

First - did you read the thread I provided a link to - if so then in that thread it showed two methods

1) using a solid copper bar with bubbler for agitation

2) using FINE copper powder with GOOD stirring

From my personal experience - when cementing Pd (or PGMs) with copper you are far better served using the copper powder method rather then the copper bar method

So if you still decide to cement with copper & you need more info about doing the copper powder method I can help you with that

That said- DMG will certainly work - have you ever used it before - if not ask & we can help

About how much Pd do you think you have in solution ?


Calcining it (burning it) is one why to reduce the DMG/Pd salt - another way is to use ion exchange with zinc & HCL --- kind of like using iron & sulfuric to reduce silver chloride

Those are the more simple methods for reduction --- other chemical reduction method of course also work but more tricky

Kurt

Thanks kurt,
yes, i read it. but i have no fine copper powder and i read too it was too expensive. DMG is too expensive too but how i come from a bad cementation process, i know it is because i did not bubles, but i think maybe learn a new method different from cementing.
i have about 200L with 0.7g/L Pd. how much DMG i will have to use? how much time it need to finish the reaction?
Could you send me more information? thank you so much. All tips are welcome.

 

[kurtak]

i have about 200L with 0.7g/L Pd.

Ok - so you have "about" 140 grams of Pd to drop (is that right?)

That is a quite a lot --- with the questions you are asking I "assume" this is your first time working with Pd in solution - is that right ?

Also what kind of refining set up are you working with - actual lab with good fume hood - vacuum filter - magnetic stir/hot plate - 20 liter flask/reaction vessel with heat mantel & overhead stir rod/bar ???? --- pics of your set up would be nice

I ask these questions because you have quite a bit of solution with a fair amount of Pd

PGM salts whether in solution or precipitated as salts that then reduction of those salt are quite toxic to work with so for safety sake how you are set up is somewhat important concerning best method to move forward in getting your Pd back

The problem with DMG precipitation is that the DMG/Pd precipitate is VERY fluffy so you get a HUGE amount of precipitate (as a salt) which is why DMG is "generally" used just to "test" if Pd is in solution &/or to precipitate "small" amounts of Pd (few grams) - it is not the best choice for larger amounts of Pd due to the LARGE amount of precipitate --- it can be done but you need a good set up --- & the precipitate is a salt so still needs to be reduced

Just a bit of the chemistry for starters -----

You need 2.5 grams of DMG to precipitate 1 gram of Pd

The DMG/Pd precipitate - when dry - is 31.67 % Pd by weight

DMG is somewhat difficult to dissolve - does not like to dissolve in water even with boiling - some people use ethanol to dissolve it but "if silver" is involved I do not recommend that as the ethanol can precipitate silver fulminate which is HIGHLY EXPLOSIVE

The only instructions I have for preparing DMG is for preparing it for testing solutions & is as follows --------

100 mil warm/hot distilled water (not boiling) add/dissolve 4 grams NaOH then add/dissolve 5.81 grams DMG

Others (like Lou, 4metals, orvi etc.) may have better instructions for precipitating large amounts of Pd with DMG

IMO (in my opinion) with the amount of Pd you have in solution I would still consider doing it with copper powder cementation - IF - you are set up with good stirring/heating set up (as asked above)

Yes copper powder is "a bit" expensive - but considering the value of the Pd not all that expensive -------

https://www.ebay.com/itm/2541784671...FAq2HXfvgSGHmOu81ZA1WWMQ==|tkp:Bk9SR-SAvuO4Yw

You want the ultra fine 325 mesh copper powder & a pound for $20 is all you should need - it can't hurt to get a couple pounds as copper powder can come in handy for other recovery/refining things

There are of course other chemical precipitation/reduction methods but those are all a bit more tricky to get right

Formic acid precipitation/reduction would be one such method --- you can do that to direct precipitate/reduce the Pd from solution - but it is a bit tricky --- or you can use it to reduce your DMG precipitate (again kind of tricky) instead of reducing the DMG/Pd by calcination (burning) or ion exchange reduction with zinc & HCl

There are other chemical methods but again they are tricky & somewhat depend on how you are set up especially considering the amount you have

Kurt

 

[100tific]

yes,kurt.
It is my first time working with Pd. I have a real lab with good fume hood, vacuum filter, hot plate but it have no magnetic stir, i have 20 liter flask/reaction vessel with heat mantel & overhead stir rod/bar too.
I didn't know i will need 2.5 grams of DMG to precipitate 1 gram of Pd.... it is too much. DMG is expensive too, and as you said, the DMG/Pd is toxic and difficult to work. I think if i calocine that i will form a lot of HCN too...
100g DMG cost 100€ in my country
1000g Cu powder cost 45€.
So even having a good lab, i think Cu powder have less risk, and it is faster and cheaper than DMG.
Thanks for that information kurt, it was really helpfull.

If i use Cu powder, i will need the bubles too? or it is only if i have a planch?
Could you say me how much Cu powder i will need? and how much time if Cu is in powder because i could see last time with a plach it cover up really fast.
i let you some picks of my lab.

 

[nickvc]

The other advantage of using copper is that you get palladium metal not salts , it will not be pure palladium but I’m guessing you are recovering it not trying to refine it so all you have to do is filter and rinse the recovered powder and then melt and assay to sell the bar.

 

[100tific]

The other advantage of using copper is that you get palladium metal not salts , it will not be pure palladium but I’m guessing you are recovering it not trying to refine it so all you have to do is filter and rinse the recovered powder and then melt and assay to sell the bar.

after the recovery i can refine it using amonnium chloride and sodium chlorate in AR if i want.

 

[kurtak]

The other advantage of using copper is that you get palladium metal not salts , it will not be pure palladium but I’m guessing you are recovering it not trying to refine it so all you have to do is filter and rinse the recovered powder and then melt and assay to sell the bar.

Per the bold print - when using atomized copper powder (plus/minus 300 mesh) for cementation you can in fact turn out pure metals or at least very near pure (99 plus) unlike when cementing with sold copper wherein yes you will get "some" copper contamination

That is not to say that you wont get some copper contamination with atomized copper - just that - if done right - you "can" turn out very near pure (if not pure) metals with atomized copper

Cementing metals (PMs) with atomized copper is quite different then cementing with solid copper

I will explain how/why this weekend when I have more time to post details (for helping 100tific with this)

Kurt

 

[kurtak]

If i use Cu powder, i will need the bubles too? or it is only if i have a planch?
Could you say me how much Cu powder i will need? and how much time if Cu is in powder because i could see last time with a plach it cover up really fast.

Very nice set up 100tific

I will answer those questions (& more) this weekend when I have time to post "details" about using atomized copper powder for cementing

Kurt

 

[rusti2]

When cementing PGMs you need to have aggressive stirring that dislodge the particles as they cement.
If not it will "plate" the Copper and effectively stop the reaction.
This can be done by air bubbling, stir bar or similar.
But the stirring need to be established before the Copper is inserted.

Agitation is the most convenient in bubbling with air the 20% oxygen content in the air tends to oxidize the solution conditions and slow down the PM reduction.

 

[kurtak]

If i use Cu powder, i will need the bubles too?

No - when using atomized copper powder you do not need the bubbler - when using a solid copper bar the reason for the bubbler is to provide agitation to the solution so that the dissolved Pd ions in the solution come in contact with copper allowing the Pd to cement out - the agitation from the bubbler also knocks the Pd off the copper bar as it cements out instead of the Pd sticking/adhering to the copper bar which happens if you don't provide agitation to the solution with the bubbler

With copper powder you still need to provide agitation to the solution so that the copper powder stays suspended in the solution during the cementing process --- in other words - the ultra fine copper particles need to stay stirred up in the solution so that they make contact with the dissolved Pd ions in the solution in order to cement out the Pd which is why I asked if you had magnetic stir/hot plate - 20 liter flask/reaction vessel with heat mantel & overhead stir rod/bar --- & you have that so that is good

one of the problems with cementing Pd (&/or any PGMs) with copper is that the PGMs tend to stick to the surface of the copper which in turn prevents the PGM ions in the solution from making contact with the copper which in turn slows down & can even stop the cementing process before the cementing process is complete - which is why with solid copper you need the agitation of the bubbler to keep the PGMs from sticking to the copper bar

The reason 300 mesh atomized copper works is the ultra fine copper particles are so small that the acid in the solution dissolves them before the PGMs have a chance to stick to the copper & stop the cementing process - BUT - the ultra fine copper powder particles NEED to stay stirred up in the solution so that they do two things

1) they make contact with the dissolved Pd (PGM) ions in the solution

2) the acid in the solution completely dissolves them (allowing the Pd/PGMs to cement out)

You may already know this but I will post this anyway - if nothing else to help others better understand how & why cementation works

Cementation is an ion exchange process wherein more reactive metal ions (like copper) go into solution & as they do so they exchange place with the less reactive metal ions (like gold silver or PGMs) thereby forcing the less reactive metals to fall out of the solution as there actual metals

In other words - more reactive metal (copper) going into solution causing less reactive metal (gold or silver or PGMs) to come out of solution

This is what is known as a redox reaction which is a reaction wherein both reduction & oxidation are happening at the "same" time --- copper is being oxidized (going into solution) while at the same time PMs are being reduced (coming out of solution)

I bring this up because just like any reaction where you have metal oxidation taking place you are going to have the foaming up reaction so need "plenty" of head room in your reaction vessel to prevent the reaction from forming up & out the top of the vessel

This is especially true when using 300 mesh atomized copper powder - the ultra fine copper particles dissolve VERY FAST causing a VERY quick & VERY aggressive foam up reaction --- so there is a bit of a learning curve to learning how much head room is needed in the vessel & how much copper to add at a time to prevent "over foaming"

This is all I have time for today --- so ------------

Could you say me how much Cu powder i will need?

Will post more tomorrow about this as well as some other things concerning cementing with copper powder

Kurt

 

[kurtak]

Could you say me how much Cu powder i will need?

This is going to depend on whether you have "free" nitric in solution - or not

This goes back to the redox reaction &/or ion exchange I talked about yesterday

For cementation to work to completion - the oxidizer (nitric) in the solution needs to be completely "used up"

In other words - the nitric needs to be completely loaded with metal ions that are nitric soluble - other wise - if there is free nitric - that free nitric will continue to dissolve nitric soluble metals (including Pd) until the nitric becomes completely loaded with metal ions

So - if you have more then one metal dissolved in the nitric - the ion exchange that pushes out (precipitates) the less reactive metal (Pd) with the more reactive metal (Cu) - only begins to really work at cementing out the Pd (to completion) when the nitric is completely loaded with metal

I other words - if there is free nitric - the nitric is going to work at dissolving Cu - until the nitric is used up by the Cu - & it is at that point - when all the nitric is used up - the actual ion exchange of Cu going into solution but also pushing out (precipitating/cementing) the Pd actually happens

Again - this is all the time I have today so will post more tomorrow

Kurt

 

[kurtak]

So --- based on my post of yesterday how much copper (powder) you will need to cement out your Pd is going to depend on how much free oxidizer is in solution that needs to be used up before the copper actually starts to cement the Pd to completion

To put this somewhat into perspective - one gallon (or 3.78 liters) of 70% (or 68%) nitric will dissolve "about" 2 pounds (or 0.907 kilo) of Cu (&/or other base metals) --- on the other hand - one gallon (or 3.78 liters) of 70% (or 68%) nitric will dissolve "about" 8 pounds (or 3.638 kilos) of silver

I bring this all up because if you have A LOT of free nitric in solution it "may" also take "a lot" of copper powder to cement out your Pd - so - you still "may" be better served to recover (&/or reduce) your Pd with DMG - or other chemical means (such as formic reduction - etc. etc.)

And here is the thing --- when you dropped the silver out of your original nitric dissolve (Ag/Pd base metals) you actually freed up more nitric

To show this here are a couple chemical reactions

AgNO3 + HCl ---> AgCl + HNO3

So - when the AgCl drops out you end up with a by product of "free" nitric

The other chemical reaction is when you use NaCl (salt) to drop the AgCl

AgNO3 + NaCl --->. AgCl + NaNO3 (sodium nitrate) aqueous

So here the by product is dissolved NaNO3 --- what I am not absolutely sure of here is if NaNO3 (aqueous) in & of itself will dissolve Cu (&/or other metals)

However - you also used HCl to "wash" your AgCl ------

I found that the silver chloride was a little pink, and i looked the solid by XRF. I found that this solid had Pd, Au and Ag.
Then, i used diluted hydrochloric acid and let it 24h, then i filter the solution.

HCl plus NaNO3 (or any nitrate salt) creates AR

AR - just like (free) nitric will dissolve more copper - before the copper actually starts to cement the Pd to completion

The thing is - that we don't know - is how much free nitric there may (or not) been left after the original nitric dissolve of your original silver/palladium/base metal alloy - &/or how much AR may have been created by the HCl wash of the AgCl

The only real way to determine how much copper powder it will take to cement your Pd is going to be to run a test on a liter or 2

Again - in as much as cementing PMs with copper powder can be a very effective why of recovering the PMs from solutions does not mean it is always the best way

In other words - sometimes - cementation with copper powder is in fact the best way to recover PMs from solutions - but - not always

Besides the things I have already posted about copper cementation there are a few other things to consider as to whether copper (powder) cementation is the best choice (in your case)

So in my next posting I will be asking you some questions

Kurt

 

[Yggdrasil]

So --- based on my post of yesterday how much copper (powder) you will need to cement out your Pd is going to depend on how much free oxidizer is in solution that needs to be used up before the copper actually starts to cement the Pd to completion

To put this somewhat into perspective - one gallon (or 3.78 liters) of 70% (or 68%) nitric will dissolve "about" 2 pounds (or 0.907 kilo) of Cu (&/or other base metals) --- on the other hand - one gallon (or 3.78 liters) of 70% (or 68%) nitric will dissolve "about" 8 pounds (or 3.638 kilos) of silver

I bring this all up because if you have A LOT of free nitric in solution it "may" also take "a lot" of copper powder to cement out your Pd - so - you still "may" be better served to recover (&/or reduce) your Pd with DMG - or other chemical means (such as formic reduction - etc. etc.)

And here is the thing --- when you dropped the silver out of your original nitric dissolve (Ag/Pd base metals) you actually freed up more nitric

To show this here are a couple chemical reactions

AgNO3 + HCl ---> AgCl + HNO3

So - when the AgCl drops out you end up with a by product of "free" nitric

The other chemical reaction is when you use NaCl (salt) to drop the AgCl

AgNO3 + NaCl --->. AgCl + NaNO3 (sodium nitrate) aqueous

So here the by product is dissolved NaNO3 --- what I am not absolutely sure of here is if NaNO3 (aqueous) in & of itself will dissolve Cu (&/or other metals)

However - you also used HCl to "wash" your AgCl ------


HCl plus NaNO3 (or any nitrate salt) creates AR

AR - just like (free) nitric will dissolve more copper - before the copper actually starts to cement the Pd to completion

The thing is - that we don't know - is how much free nitric there may (or not) been left after the original nitric dissolve of your original silver/palladium/base metal alloy - &/or how much AR may have been created by the HCl wash of the AgCl

The only real way to determine how much copper powder it will take to cement your Pd is going to be to run a test on a liter or 2

Again - in as much as cementing PMs with copper powder can be a very effective why of recovering the PMs from solutions does not mean it is always the best way

In other words - sometimes - cementation with copper powder is in fact the best way to recover PMs from solutions - but - not always

Besides the things I have already posted about copper cementation there are a few other things to consider as to whether copper (powder) cementation is the best choice (in your case)

So in my next posting I will be asking you some questions

Kurt

Another excellent example of why we can't answer a simple question with a simple answer.
Sometimes there is no simple answer.

 

[Triton]

Ok - so you have "about" 140 grams of Pd to drop (is that right?)

That is a quite a lot --- with the questions you are asking I "assume" this is your first time working with Pd in solution - is that right ?

Also what kind of refining set up are you working with - actual lab with good fume hood - vacuum filter - magnetic stir/hot plate - 20 liter flask/reaction vessel with heat mantel & overhead stir rod/bar ???? --- pics of your set up would be nice

I ask these questions because you have quite a bit of solution with a fair amount of Pd

PGM salts whether in solution or precipitated as salts that then reduction of those salt are quite toxic to work with so for safety sake how you are set up is somewhat important concerning best method to move forward in getting your Pd back

The problem with DMG precipitation is that the DMG/Pd precipitate is VERY fluffy so you get a HUGE amount of precipitate (as a salt) which is why DMG is "generally" used just to "test" if Pd is in solution &/or to precipitate "small" amounts of Pd (few grams) - it is not the best choice for larger amounts of Pd due to the LARGE amount of precipitate --- it can be done but you need a good set up --- & the precipitate is a salt so still needs to be reduced

Just a bit of the chemistry for starters -----

You need 2.5 grams of DMG to precipitate 1 gram of Pd

The DMG/Pd precipitate - when dry - is 31.67 % Pd by weight

DMG is somewhat difficult to dissolve - does not like to dissolve in water even with boiling - some people use ethanol to dissolve it but "if silver" is involved I do not recommend that as the ethanol can precipitate silver fulminate which is HIGHLY EXPLOSIVE

The only instructions I have for preparing DMG is for preparing it for testing solutions & is as follows --------

100 mil warm/hot distilled water (not boiling) add/dissolve 4 grams NaOH then add/dissolve 5.81 grams DMG

Others (like Lou, 4metals, orvi etc.) may have better instructions for precipitating large amounts of Pd with DMG

IMO (in my opinion) with the amount of Pd you have in solution I would still consider doing it with copper powder cementation - IF - you are set up with good stirring/heating set up (as asked above)

Yes copper powder is "a bit" expensive - but considering the value of the Pd not all that expensive -------

https://www.ebay.com/itm/254178467105?itmmeta=01HQ33FG0R6RDVZ4R0Z1FMBHY3&hash=item3b2e379d21:g:EzUAAOSwo~1az4ny&itmprp=enc:AQAIAAAA8ILdYL/KMz+J06A7xIchavl8gW7SlnwZ8TP7QwuuYOByWSDvdjG7vRX9qc2p8xPt9LUZc/oJpOGPexAlTjZEuLEZnl8GaWV8PxMN0t3Ekfl4m1d5dpcUUfM62jEnyZYxpMegVfrynpHeTnEtWJgslW0l4wd63UW9xv661S5r0J16r/ouej/qqGk0ovqKfXpyDLcXifdX1Qsku1LWmTe1GHf/BBG9Ku5ZWAtShQWkD2S0IZnEDRdYSQvJBZn76bv8hdRp5hGKpAFWPMnWZ+qM+xiPkCc0NJG9VCLmgqqpwVFAq2HXfvgSGHmOu81ZA1WWMQ==|tkp:Bk9SR-SAvuO4Yw

You want the ultra fine 325 mesh copper powder & a pound for $20 is all you should need - it can't hurt to get a couple pounds as copper powder can come in handy for other recovery/refining things

There are of course other chemical precipitation/reduction methods but those are all a bit more tricky to get right

Formic acid precipitation/reduction would be one such method --- you can do that to direct precipitate/reduce the Pd from solution - but it is a bit tricky --- or you can use it to reduce your DMG precipitate (again kind of tricky) instead of reducing the DMG/Pd by calcination (burning) or ion exchange reduction with zinc & HCl

There are other chemical methods but again they are tricky & somewhat depend on how you are set up especially considering the amount you have

Kurt

Thank you, this is some real quality info!! I currently have A LOT of pd solution and this should help the final home stretch. Beers on me!