Processing MLCC's

[MicheleM]

@Sancho_n_Pedro I would say to process them separately, I only tried a test on 80 g of magnetic ones (magnetic : they stick to non strong magnets even if you try to shake them off), they gave only a little amount of silver and almost zero Pd (positive to the stannous test but not worth the effort to proceed further) but I got a lot of waste liquid because the water washing. I still have 20 g of non magnetic/slightly magnetic (to HDD magnet) , I decide to keep them for future experiments
Edit.: Mlcc from 2003-2013 devices

 

[orvi]

To the best of my knowledge smelting tend to squeeze more values from the MLCC powder.
But smelting need to be high temp or very aggresive to dissolve the stubborn ceramics used. I mostly know about old THT MLCCs (USSR, Bulgarian etc.), not modern type SMD MLCCs.
Old ones are often titanate ceramics, which are pain to process, and very high temperatures are needed to properly liquify the substrate - with addition of sand as flux for high temp eutectics (above 1500°C) in induction furnance.
Cryolite/fluorspar basic fluxes could work on lower temperatures. Just soda ash or borax do not melt all the ceramic, and just coat the grains of it.
However, with old ones. Maybe these "new" SMD could be dissolved more easily.

 

[Geo]

MLCC's Are problematic. Even the highly magnetic ones will still contain some value, mostly silver, and very little Pd. If I were smelting, I would run them together as the nickel will not pose problems in refining the precious metal later. But, if I am leaching in acid, I would simple keep the magnetic portion for the next smelt. Leach the MLCC's in nitric acid only. In my experience, the alumina will break down into powder. There will be values available in the material until all of the alumina has been broken down. Crushing or milling will speed the process but is not necessary when acid leaching. Heat speeds the reaction but be prepared for the mess on your glassware when finished. High heat will fuse some of the alumina tightly to the glass. I found that adding a little ammonia to the wash will help bring it off the glass easier.

 

[Geo]

Personally, I developed a process of using CuCl2 on whole boards and collecting the components that doesn't dissolve. Careful screening provides me with all of the SMD's at the end of the process. Be warned, CuCl2 can and will dissolve Pd. PH should be as high as possible but still acidic enough to dissolve the copper. At the end of the CuCl2 leach, if the CuCl2 is bright emerald green, test the solution with stannous chloride. Leave the test overnight to ensure complete reaction. I use 25 gallons of solution per batch. Even a light positive could be a substantial amount. If there is a positive with the stannous test, add some copper metal without air added for several days. Remove the solution from the top down and collect any black powder accumulated on the bottom of the container.
To answer a couple of questions before hand, the higher reactive metals, such as tin in solder which creates stannous chloride in situ, the tin eventually oxidizes in solution (if you are adding air) and will make a white powder of tin oxide. Some plastic will break down into a gooey, jelly like substance. A trick I learned is to take a sample of each type of connector or other type of plastic common on circuit boards and soak them in HCl just to see which holds up and which dissolves. Plasticized PVC will dissolve in HCl. A simple mechanical test is to twist the plastic being tested. If it snaps before twisting, it will be safe in CuCl2. If it twisted all the way around without snapping, it will dissolve in CuCl2.

 

[dpgold]

Hi, I want to start a batch of MLCC processing, to get rid of the solder ends. My thinking is to put them in HCL diluted with some distilled water, maybe 50-50. Than I will use that used HCL to dissolve solder on other RAM boards. I was thinking to process them all together what would be your advice?

 

[Geo]

Be sure to roast the material before going from HCl to nitric acid unless you intend to make aqua regia. You can not rinse acid off with just water. As the nitric acid encounters the silver it contains, it will form silver chloride which will mix with the alumina powder from the MLCC's and will be impossible to separate without costing more than it's worth.

 

[dpgold]

After I get rid of the solder I incinerate them, then wash and then I would use AR. But how then it comes to the separate precipitation of silver and other PM, what would be the process at that point?

 

[Geo]

Do not use AR. Leach MLCC;s in nitric acid only. Then you drop the silver as silver chloride with HCl and that leaves a relatively pure palladium solution to work with. If you can't source nitric acid, use poor man's nitric acid.

 

[dpgold]

Do not use AR. Leach MLCC;s in nitric acid only. Then you drop the silver as silver chloride with HCl and that leaves a relatively pure palladium solution to work with. If you can't source nitric acid, use poor man's nitric acid.

Thank you so much, I am feeling more and more confident with stuff. I had made small experiments, I had dissolved a few gold fingers in AR and then (after testing with stannous-pozitive) I added some other pins and stuff which contains gold to use all the nitric.
At some point something happened that the gold came out of solution (probably cementation) or nitric finished its strength so that when I tested again there was no more gold in solution. There was very little nitric to begin with. I added the test batch to a bigger AP batch. Did I mess up?

 

[Geo]

Thank you so much, I am feeling more and more confident with stuff. I had made small experiments, I had dissolved a few gold fingers in AR and then (after testing with stannous-pozitive) I added some other pins and stuff which contains gold to use all the nitric.
At some point something happened that the gold came out of solution (probably cementation) or nitric finished its strength so that when I tested again there was no more gold in solution. There was very little nitric to begin with. I added the test batch to a bigger AP batch. Did I mess up?

Well, as long as it wasn't a lot. You never want to add nitric acid in any form to copper(II) chloride. Been there, done that. Went to dump a bucket of waste solution in a waste drum and huge slug of NO2 came up and hit me in the face. I would have sworn all the nitric had been neutralized.
The electromotive series of metals tells us that when you add an acid to a mixed metals batch, and the acid attacks more than one metal present, the acid will attack the more reactive metal first. In other words, if you had silver and copper metal and added nitric acid to the mix, the copper will dissolve first before the silver begins to dissolve. That's the reason we can use copper to cement precious metal. Copper will only cement metal that is less reactive than itself.

 

[Rreyes097]

Do not use AR. Leach MLCC;s in nitric acid only. Then you drop the silver as silver chloride with HCl and that leaves a relatively pure palladium solution to work with. If you can't source nitric acid, use poor man's nitric acid.

But doesn't that form aqua regia,?

 

[Yggdrasil]

But doesn't that form aqua regia,?

No that is poor mans AR. If you mix Nitrates and HCl you get poor mans AR.
Just drop the HCl.
I have not used it so search the forum for poor mans Nitric.

Edited for clarity

 

[kurtak]

Geo Posted

Do not use AR. Leach MLCC;s in nitric acid only. Then you drop the silver as silver chloride with HCl and that leaves a relatively pure palladium solution to work with. If you can't source nitric acid, use poor man's nitric acid.

Then Rreyes097 asked

But doesn't that form aqua regia,?

Rreyes097 --- I think you miss understand what Geo is saying here - so to clarify

IF (the BIG IF) you are going to leach MLCCs - do NOT use AR to leach the MLCCs --- that is because the AR will create silver chloride which will then end up being tied up in & lost in the ceramic mud during the leach process

So - you need to use nitric ONLY for the leaching part of the process as the nitric ONLY will dissolve both the Ag & the Pd

Then you wash/filter the nitric leach out of the ceramic mud

Then - once you have the nitric ONLY Ag/Pd solution washed out of ceramic mud you add HCl (or salt water) to the solution in order to drop the Ag as AgCl

Then - after you have dropped the Ag out of the solution as AgCl - the Pd is still dissolved in the solution

So - you then wash/filter the still dissolved Pd out of the AgCl

You can then drop the (still dissolved) Pd you just washed out of the AgCl by using ether the cementing process - or the sodium carbonate/formic acid process - or precipitation with DMG --- &/or other (more complicated) processes that recover Pd from solution

I said -----

IF (the BIG IF) you are going to leach MLCCs

The reason I posted that in bold print is that IMO (In My Opinion) leaching MLCCs - even in small batches is one of the worst ways to go about recovering the Ag & Pd from MLCCs for a number of reasons

1) during the leaching - the ceramic breaks down into an ULTRA fine mud - like clay which is impossible to filter --- so you have to let the ceramic mud settle then decant the leach - then wash with water - let settle & decant again AND you have to do that multiple times AND it is next to impossible to get all the Ag/Pd washed out - at the very best at least traces of Ag/Pd will stay tied up in the ceramic mud

2) So you will end up with a LOT of VERY diluted Ag/Pd solution which you will then want to evaporate back down - otherwise when you go to drop the Ag as AgCl - the AgCl will come down ULTRA fine - so fine it will likely cause washing/filtering problems when you go to wash the still dissolved Pd out of the AgCl

3) washing the Pd out of the AgCl presents the same problem as washing the Ag/Pd out of the ceramic mud - it takes a LOT of washing to get all the Pd washed out resulting in a VERY diluted solution again (if you are not set up to vacuum filter --- vacuum filtering does NOT work on the ceramic mud - but will on the AgCl)

4) then you still need to deal with the chem waste in the end of the above

5) then - you still need to convert AgCl to actual silver - a whole other process in & of its self

IMO - its a long & tedious process that creates chem waste that needs to be dealt with for safe disposal

I am not saying it can't be done - just not the best way

IMO - smelting is the best way to go for processing MLCCs - even in small batches

Kurt

 

[Yggdrasil]

Geo Posted

Then Rreyes097 asked

Rreyes097 --- I think you miss understand what Geo is saying here - so to clarify

IF (the BIG IF) you are going to leach MLCCs - do NOT use AR to leach the MLCCs --- that is because the AR will create silver chloride which will then end up being tied up in & lost in the ceramic mud during the leach process

So - you need to use nitric ONLY for the leaching part of the process as the nitric ONLY will dissolve both the Ag & the Pd

Then you wash/filter the nitric leach out of the ceramic mud

Then - once you have the nitric ONLY Ag/Pd solution washed out of ceramic mud you add HCl (or salt water) to the solution in order to drop the Ag as AgCl

Then - after you have dropped the Ag out of the solution as AgCl - the Pd is still dissolved in the solution

So - you then wash/filter the still dissolved Pd out of the AgCl

You can then drop the (still dissolved) Pd you just washed out of the AgCl by using ether the cementing process - or the sodium carbonate/formic acid process - or precipitation with DMG --- &/or other (more complicated) processes that recover Pd from solution

I said -----

IF (the BIG IF) you are going to leach MLCCs

The reason I posted that in bold print is that IMO (In My Opinion) leaching MLCCs - even in small batches is one of the worst ways to go about recovering the Ag & Pd from MLCCs for a number of reasons

1) during the leaching - the ceramic breaks down into an ULTRA fine mud - like clay which is impossible to filter --- so you have to let the ceramic mud settle then decant the leach - then wash with water - let settle & decant again AND you have to do that multiple times AND it is next to impossible to get all the Ag/Pd washed out - at the very best at least traces of Ag/Pd will stay tied up in the ceramic mud

2) So you will end up with a LOT of VERY diluted Ag/Pd solution which you will then want to evaporate back down - otherwise when you go to drop the Ag as AgCl - the AgCl will come down ULTRA fine - so fine it will likely cause washing/filtering problems when you go to wash the still dissolved Pd out of the AgCl

3) washing the Pd out of the AgCl presents the same problem as washing the Ag/Pd out of the ceramic mud - it takes a LOT of washing to get all the Pd washed out resulting in a VERY diluted solution again (if you are not set up to vacuum filter --- vacuum filtering does NOT work on the ceramic mud - but will on the AgCl)

4) then you still need to deal with the chem waste in the end of the above

5) then - you still need to convert AgCl to actual silver - a whole other process in & of its self

IMO - its a long & tedious process that creates chem waste that needs to be dealt with for safe disposal

I am not saying it can't be done - just not the best way

IMO - smelting is the best way to go for processing MLCCs - even in small batches

Kurt

I think he refers to mixing Nitrates with HCl.
But poor mans Nitric, is Nitrates alone is it not?

 

[kurtak]

I think he refers to mixing Nitrates with HCl.
But poor mans Nitric, is Nitrates alone is it not?

Per the bold print -------

Poor mans nitric is made with nitrates (sodium or potassium nitrate) plus sulfuric acid

Poor mans AR is made with nitrates (sodium or potassium nitrate) plus HCl

Kurt

 

[orvi]

Per the bold print -------

Poor mans nitric is made with nitrates (sodium or potassium nitrate) plus sulfuric acid

Poor mans AR is made with nitrates (sodium or potassium nitrate) plus HCl

Kurt

And if you can source calcium nitrate fertilizer, you can make relatively sulfate free nitric. Calcium sulfate formed is fairly insoluble in nitric acid solutions, and can be filtered out - and remaining solution used.

 

[Geo]

And if you can source calcium nitrate fertilizer, you can make relatively sulfate free nitric. Calcium sulfate formed is fairly insoluble in nitric acid solutions, and can be filtered out - and remaining solution used.

Except for using the solid nitrate salt. Dissolved calcium will come down with the addition of any kind of sulfate or sulfuric acid as calcium sulfate. Dropping gold from a solution with dissolved calcium is nearly impossible with SMB. The calcium will rob the solution of the SO2 while forming calcium sulfate.

 

[Yggdrasil]

Except for using the solid nitrate salt. Dissolved calcium will come down with the addition of any kind of sulfate or sulfuric acid as calcium sulfate. Dropping gold from a solution with dissolved calcium is nearly impossible with SMB. The calcium will rob the solution of the SO2 while forming calcium sulfate.

There should not be much Calcium left after the addition of Sulfuric should there?
Just test by adding a bit more Sulfuric I guess.

 

[Geo]

There should not be much Calcium left after the addition of Sulfuric should there?
Just test by adding a bit more Sulfuric I guess.

That is one way to remove it. It will precipitate as a white pearlescent powder. Surprisingly, the fluffy white powder is very porous and filters with little problem.

 

[Yggdrasil]

That is one way to remove it. It will precipitate as a white pearlescent powder. Surprisingly, the fluffy white powder is very porous and filters with little problem.

If you reread Orvis post you will see that, that was his point.