Refining MLCC´s for Palladium and Silver !

[kurtak]

One more note - you said ---------

I have technical reasons to believe the material will contain significant AU, PT, RH, as well as AG and PD

If it is the seller telling you all those metals are in MLCCs you are more then likely being scammed

There is NO Rh in MLCCs

Au ONLY if they are "plated" on the ends (which is rare)

Pt ONLY if they are OLD Soviet MLCCs

Ag/Pd if made BEFORE 1997 - if made AFTER 1997 MOST likely Cu/Ni

Kurt

 

[Lars100]

Thanks for the suggestions. I have 25 kilos of old MLCCs, and am in process of planning the refining project. I have technical reasons to believe the material will contain significant AU, PT, RH, as well as AG and PD. Any suggestions how to proceed stepwise to recover all?

Hello there !
I have done about 30kg but Im not at the end yet. I believe I have some good ideas to share...but...I will hold back a little as I don´t now if it will work out. See my comments to Geo ! I will tell when I´m succesful (or just fade away if I don´t...) !

 

[Lars100]

@Lars100
I concur with Kurt. Storing ionized Pd is a dangerous situation. Accidents happens, an act of god, an earthquake or storm. It's better to keep that kind of toxin in metallic form until you are ready to go from start to finish. This reduces the time that the metal is most deadly. There was two great people from this forum that I knew personally, and a third that's suspected, that has died from complications of platinosis.
Since the Pd came from MLCC's, it should be pretty pure as it is. Move the solution to a large enough beaker to hold the solution and still have 2/3 to 3/4 of the volume empty. Add 50ml's of HCl to drop the silver as silver chloride. Filter the silver out and replace the solution to the beaker. Dilute the solution to double it's volume. Start adding small amount of steel wool while stirring. The steel wool will have the tendency to float. It needs to stay submerged as much as possible. This will produce a small amount of aerosol from the reaction, so wear gloves and a mask if you are not working in a fume hood. Keep adding the steel wool until the solution loses it's red color and turns slightly green. It will produce a light, fluffy black powder. You may see small bits of steel wool that does not react. Don't be alarmed as steel contains carbon. What you are seeing will be the carbon retaining the shape. It is of no consequence to the recovery or melting of the powder. Ideally, you would continue adding steel until you get a negative stannous chloride test result. You will have to settle for a colorless solution except for the before mentioned light green color. Filter all black powder out of solution. Now you have a mostly purified black powder of Pd called (PGM blacks). You can melt as is or store and add more to it later. Don't be surprised at the volume of the black powder. It makes a huge volume of powder that dries to a much smaller mass. It dries up next to nothing to be honest. It will make you think it evaporated off but that's just the nature of cemented powder. Now your palladium is much less dangerous than it was as a liquid. The powder will be very fine and light and can be lifted into the air by a small puff of wind. The black powder is still just as toxic as the liquid so take great care to capture all of the powder and store it damp until you are ready to melt it.

Hi Geo !
Now I´m a bit further ! Stannous test has been performed with good results and happily I started with the next step.
In short, there was a rather huge reaction when I started to add steel wool and for just a short while it turned towards green but then the bubbles started to become brown and brown they stayed.
After finish it I filtered it and the brown mass stayed in the filter while I got a black liquid with a shimmering fluid on the surface in the beaker. I did another sample in which Im pretty certain there were no silver at all remaining in the fluid. But same result.
Please see attached pic of a stannous test of a sample. Does it say anything ? Strip is dark brown and the filter-paper is orange/black/greenish...

 

[kurtak]

Please see attached pic of a stannous test of a sample.

Is that the stannous test before - or after putting the steel wool in your solution ?

Kurt

 

[kurtak]

After finish it I filtered it and the brown mass stayed in the filter

I could be wrong - but - it sounds like the steel wool cemented copper

Which would be the case IF (the BIG IF) the MLCCS were BME MLCCS instead of NME MLCCs

Cemented Pd should be a "dark" gray to black - not brown

Can you post a pic of the brown mass that stayed in your filter ?

Kurt

 

[kurtak]

I will tell when I´m succesful (or just fade away if I don´t...) !

Per the bold print - please - whether you have good results - or - bad results - post your results

posting bad results is just as important as posting good results as even bad results is part of the learning/teaching process --- which is what the purpose of this forum is (learning/teaching)

Edit to add; - when I first started to learn about refining - I had to post about A LOT of bad results - that is how I learned to get good results

Kurt

 

[Geo]

pH plays a part in successfully cementing Pd. If the solution is acidic enough, the finely divided Pd will simply redissolve after the steel wool is depleted. There are two easy ways to help the process. Dilute the solution with water or raise the pH by adding hydroxide or carbonate dissolved in water to the solution in small increments. Unless you have done other processes with the solution since the leaching process, the solution will most likely have a pH of 0. You want to adjust it up to 2. If the solution is saturated with metal salt, this will cause some oxides to form. But again, Pd will not leave the solution easily. As you are adding the base, watch for a cloud to form in the solution. It should redissolve on it's own if you are doing the additions and stirring correctly. Stop adding the base when a cloud forms and does not redissolve in a few minutes time. Filter the solution and cement again. Ideally, you want the steel wool to neutralize the solution to the point that the Pd does not redissolve. If you have 1000mls of solution and for what ever reason you can't get anything to work right, dump it in a bucket and add a gallon of water. Now it will cement on iron and will not go back into solution so fast that you can't collect the powder. This creates a lot of liquid waste and should be avoided if at all possible.

 

[Lars100]

Is that the stannous test before - or after putting the steel wool in your solution ?

Kurt

Hi Kurt !
Thanks for taking time with this.
- I will take some more pictures tomorrow showing stannous and what samples I took/and what I did.
Thanks for Your patience.
Br Lars

 

[Lars100]

pH plays a part in successfully cementing Pd. If the solution is acidic enough, the finely divided Pd will simply redissolve after the steel wool is depleted. There are two easy ways to help the process. Dilute the solution with water or raise the pH by adding hydroxide or carbonate dissolved in water to the solution in small increments. Unless you have done other processes with the solution since the leaching process, the solution will most likely have a pH of 0. You want to adjust it up to 2. If the solution is saturated with metal salt, this will cause some oxides to form. But again, Pd will not leave the solution easily. As you are adding the base, watch for a cloud to form in the solution. It should redissolve on it's own if you are doing the additions and stirring correctly. Stop adding the base when a cloud forms and does not redissolve in a few minutes time. Filter the solution and cement again. Ideally, you want the steel wool to neutralize the solution to the point that the Pd does not redissolve. If you have 1000mls of solution and for what ever reason you can't get anything to work right, dump it in a bucket and add a gallon of water. Now it will cement on iron and will not go back into solution so fast that you can't collect the powder. This creates a lot of liquid waste and should be avoided if at all possible.

Thanks Geo !
Im so glad that You have answers for me. I will go back tomorrow and take some more pics. I was suspecting that my mixture is wrong. Im pretty sure I have to much acid for ex. I added the same amount of diluted water to the fluid and then started to feed with steel-wool...well...it boils and smoke (yes, I was prepared for it). It calmed down and I added more steel-wool...new boiling session...and so on a couple of times until the steel-wool didn´t react anymore.
Pictures are coming tomorrow...
But one question here...adding the steel wool...in the best scenario I will end up with steel and PD, right ? How will I get rid of the steel ?

 

[Geo]

Thanks Geo !
Im so glad that You have answers for me. I will go back tomorrow and take some more pics. I was suspecting that my mixture is wrong. Im pretty sure I have to much acid for ex. I added the same amount of diluted water to the fluid and then started to feed with steel-wool...well...it boils and smoke (yes, I was prepared for it). It calmed down and I added more steel-wool...new boiling session...and so on a couple of times until the steel-wool didn´t react anymore.
Pictures are coming tomorrow...
But one question here...adding the steel wool...in the best scenario I will end up with steel and PD, right ? How will I get rid of the steel ?

The dissolved steel will not be an issue. It will stay in solution until the solution is completely neutralized. Any metallic steel left can be removed with a magnet. There will be a noticeable amount of carbon left behind from the steel. Steel is a man made metal. It is created by mixing iron and carbon primarily. Steel is a soft metal compared to iron. Iron has a crystalline structure that makes iron very hard, but brittle. Other additives gives it different properties. Iron can not be cemented from solution. Once it's dissolved, it's locked in the solution and can not effect future processing with the simple processes we use. The carbon left behind from the steel will convert to carbon dioxide well before PGM's melt.

 

[Lars100]

Dear all,
So, please see attached pics. Pictures showing what I got and then I do stannous test. First pictures show "the mass I got when adding steel wool to my acid fluids (filtered MLCC solution after being in Nitric acid and then silver separated with HCL -see earlier comments). I added extra steel wool in the end of the process and let it stay overnight. It turned out the the process wasn´t finished so that steel wool dissolved to. Pic 2 shows after stiring it together. The mass blackened but I must say it´s still more brown (pic2).
I filtered the lot I made last week (same procedure) and the filterer "steel wool" can be seen in Pic 3.
I used another method earlier (from Youtube) where I neutralized the acid with Sodium carbonate (pic 4) and pic 5 shows the result after boiling it down.

Stannoust testing.
Pic6 shows the setup of above samples. Pic 7. shows the result after just adding the stannous fluid (30sec). Pic 8 after 2 min and Pic 9 after 5 min.
I look forward to hear Your comments/conclusions of it all !

 

[Lars100]

The dissolved steel will not be an issue. It will stay in solution until the solution is completely neutralized. Any metallic steel left can be removed with a magnet. There will be a noticeable amount of carbon left behind from the steel. Steel is a man made metal. It is created by mixing iron and carbon primarily. Steel is a soft metal compared to iron. Iron has a crystalline structure that makes iron very hard, but brittle. Other additives gives it different properties. Iron can not be cemented from solution. Once it's dissolved, it's locked in the solution and can not effect future processing with the simple processes we use. The carbon left behind from the steel will convert to carbon dioxide well before PGM's melt.

Geo, ah a magnet !!! The easiest is the best !!! Now I can only hope I got the "right stuff". Please see my new inlay !
Many thanks for sharing Your knowledge and experience !

 

[Lars100]

Per the bold print - please - whether you have good results - or - bad results - post your results

posting bad results is just as important as posting good results as even bad results is part of the learning/teaching process --- which is what the purpose of this forum is (learning/teaching)

Edit to add; - when I first started to learn about refining - I had to post about A LOT of bad results - that is how I learned to get good results

Kurt

Thanks Kurt !
Yes, I know...I get super frustrated when I read a thread (about anything) and it ends up in nothing. Either the problem has been solved or not... The person in charge of the thread is gone...happy with a solution he/she didn´t share or just sad with an unsolved issue...
- Today I´ve made a new post. I look forward to hear Your thoughts of it !
Br - Lars

 

[jphayesjr]

Thanks for the tips, the reels on which some of my MLCCs came indicate they contain the other PGM, and yes, some have gold or Pt/Pd plated caps. These were used yo repair civilian radios, avionics, radars, sonar, and yes, they are rare.

 

[jphayesjr]

Maybe some super-fancy with gold plated ends I also do not know what else should be in there. Old Soviet MLCCs sometimes used platinum, not palladium. Some batches of mixed MLCCs gave even 50/50 PtPd mix. Never heard about Rh or gold inside. But in modern stuff... I doubt even about palladium. From the point when sinter technology for nickel developed for MLCCs, Pd ones are very scarce.

During the 1980s and 1990s, Rh was often not even refined out of other PGMs, or gold or silver, it was a cheaper substitute for PT/Pd, it's only large scale commercial use was anti-corrosive plating on silver, especially jewelry.

 

[kurtak]

pH plays a part in successfully cementing Pd. If the solution is acidic enough, the finely divided Pd will simply redissolve after the steel wool is depleted.

Geo - I am sorry but this simply is not true - Ph plays little or no role in cementing Pd from an acidic solution

At least not in a nitric solution or an AR solution

There is one exception to that & that is when Pd is dissolved in CuCl2 - when Pd is dissolved in CuCl2 you get PdCl2 --- CuCl2 & PdCl2 are Co-catalyst --- so - during the reaction (when trying to cement Pd from CuCl2) PdCl2 is reduced to Pd - and then the CuCl2 serves to re-oxidize (redissolve) this back to PdCl2. Air can then oxidize the resultant CuCl back to CuCl2, completing the cycle.

This makes cementing Pd from a CuCl2 solution very difficult - therefore - yes - in the case of Pd dissolved in CuCl2 you may well have to adjust Ph (up) in order to overcome the Co-catalyst cycle (PdCl2 being reduced to Pd by cementing - the CuCl2 redissolving the Pd to PdCl2 - in a continuing ongoing cycle)

Pd dissolved in a nitric &/or AR can be cemented form those solutions - directly - without the need to dilute &/or adjust Ph --- & cementing with copper is the preferred metal for doing the cementing

Cementing PGMs (including Pd) with copper - from nitric & AR - has been a long standing "standard" in LARGE scale refineries forever & they do so without the need to adjust Ph

They use copper to cement PGMs from AR after dropping the gold in AR solutions that also have PGMs in them

The same holds true (cementing with copper - without the need to adjust Ph) in nitric solutions that have PGMs dissolved in them

The fact of the matter is - you can cement Pd directly from a "concentrated" nitric or AR solution --- however - diluting the solutions - "a little" (like two or three times) does not hurt - but you most certainly do not have to dilute so much as to change the Ph by a factor of 2 --- in fact doing so will dilute it so much it (the Pd) will come down "ultra " fine --- not a good thing

To put that (diluting to change Ph) in perspective --------

To change Ph from 0 to 1 --- you have to dilute 10 times --- that means you would have to dilute 1 liter to 10 liters

To change Ph from 0 to 2 --- you have to dilute 100 time --- that means you would have to dilute 1 liter to 100 liters

To change Ph from 0 to 3 --- you have to dilute 1000 times --- that means you would have to dilute 1 liter to 1000 liters

That is a LOT of diluting - even to change Ph from 0 to 1 - & it is not necessary

Adjusting Ph with a base also in not necessary - nor do you want to do so - if you don't need to - it can & is likely to lead to "other" complications

Cementing with iron is a VERY dirty/messy way of going about this when it can be done with copper resulting in MUCH cleaner cementing

Bottom line - there are simpler & "cleaner" ways to get this done

Kurt

 

[jphayesjr]

Should add, I'll be getting up to75 k more soon, all from a defunct repair company on original reels, will be looking into professional refiners. The engineers out there know how a scaled up process will differ from benchtop assay methods. I know I need to have a good grasp of the processes and chemical equations involved for all the best reasons, to choose someone who offers the best options.

An image of one of literally trunks full, price was retail for reel in-trade only...coding on obverse indicates they were made in late 80s to early 90s

 

[Lars100]

I could be wrong - but - it sounds like the steel wool cemented copper

Which would be the case IF (the BIG IF) the MLCCS were BME MLCCS instead of NME MLCCs

Cemented Pd should be a "dark" gray to black - not brown

Can you post a pic of the brown mass that stayed in your filter ?

Kurt

Hello Kurt !
I believe You have a point here. All the MLCC´s I got are from 2005 or older and about 50% are coming from Samsung. According to their own specification from that time they say that the inner electrode is made of Ni or Pd. The outer electrode consist of three layers made of Cu or Ag (inner), Ni (middle) and Sn/Pb (outer). We had the components laying in 15% HCL for a week to wash away the outer layer and I believe we were fairly succesful in doing that (outside layer diminished and changed color).
- I will post some more pics of the "brown mass" shortly !!!
Thanks for Your time and good ideas !

 

[Lars100]

Hello Kurt !
I believe You have a point here. All the MLCC´s I got are from 2005 or older and about 50% are coming from Samsung. According to their own specification from that time they say that the inner electrode is made of Ni or Pd. The outer electrode consist of three layers made of Cu or Ag (inner), Ni (middle) and Sn/Pb (outer). We had the components laying in 15% HCL for a week to wash away the outer layer and I believe we were fairly succesful in doing that (outside layer diminished and changed color).
- I will post some more pics of the "brown mass" shortly !!!
Thanks for Your time and good ideas !

Hello again !
Please see attached pics. I didn´t "feed" the first batch so well with steel wool so it was very "wet". I filtered it and as You can see the filter is very brown while the liquid is green/black.
In the second batch I had more steel wool so it became a thicker mass (no running fluid). To my surprise the top layer is very brown while the underneath mass is more black/grey but is has indeed also a lot of brownish in it.

 

[kurtak]

Hello again !
Please see attached pics. I didn´t "feed" the first batch so well with steel wool so it was very "wet". I filtered it and as You can see the filter is very brown while the liquid is green/black.
In the second batch I had more steel wool so it became a thicker mass (no running fluid). To my surprise the top layer is very brown while the underneath mass is more black/grey but is has indeed also a lot of brownish in it.

Please STOP what you are doing - you are creating MESSES that we are now (likely) going to have to clean up

I say likely clean up because IF (the BIG IF) there was actually Pd in your solution(s) that Pd is now likely tied up in that brown mass - so now we will likely need to clean that up

That brown mass is iron oxide (basically rust) as a result of using steel wool in a nitric solution

Put those filters in a plastic container with a lid on them so they don't dry out (we "may" need to come back to them)

Put the solutions aside until we are able to discuss this in more detail --- in other words - slow down & in fact stop until "others" have chimed in - instead of just jumping in on the advice of one person

I say that because "sometimes" there are mis-understandings in what is posted - which may (or not) lead to mistakes made in the advice given - so it is always good to "wait" & hear what others have to say as someone else may catch the mis-understanding & correct it

I believe that is the situation here

Steel wool does not work well in a nitric solution (which is what you have) & we are now seeing the results of that

Steel wool is better suited with HCl solutions

So Geo did not give bad advice - I "think" he just mis-understood your situation --- waiting for "others" to chime in "may" have avoided the mess(es) you have now created

Trust me - I to sometime mis-understand what I read - post a reply - & then someone else has to correct me

My point being - as someone still learning - slow down & wait for others to chime in so that discussions are more complete - instead of just jumping in on the advice of "one" post

To be continued (all I have time for today)

Kurt