# Palladium precipitation by formic acid



## sayf (Oct 9, 2022)

Hello guys, i usually precipitate palladium using DMG, but i want to try the formic acid method. so If the solution contains some copper will i get a clean palladium precipitate if i use this method ?


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## orvi (Oct 10, 2022)

If done right, quality will be comparable or even better than that DMG dropped Pd. pH control is key for clean precipitation. Too high pH and copper alongside with other base metals can co-precipitate from the solution as oxohydroxides or other hydrolyzed species.


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## sayf (Oct 10, 2022)

orvi said:


> If done right, quality will be comparable or even better than that DMG dropped Pd. pH control is key for clean precipitation. Too high pH and copper alongside with other base metals can co-precipitate from the solution as oxohydroxides or other hydrolyzed species.


As i read the ph should be around 4 before dropping the palladium with formic acid, am i correct ?


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## Alondro (Oct 10, 2022)

sayf said:


> As i read the ph should be around 4 before dropping the palladium with formic acid, am i correct ?


pH4 is actually on the higher side. Between 2-4 is the optimum range, from every protocol I can find.


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## Alondro (Oct 10, 2022)

orvi said:


> If done right, quality will be comparable or even better than that DMG dropped Pd. pH control is key for clean precipitation. Too high pH and copper alongside with other base metals can co-precipitate from the solution as oxohydroxides or other hydrolyzed species.


The scientific papers on the process I read suggested as high a purity as 99.7% was possible when reduction conditions were well-controlled and optimized. 

But getting as much silver out as possible first from mixed solutions was very important.


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## orvi (Oct 10, 2022)

Alondro said:


> pH4 is actually on the higher side. Between 2-4 is the optimum range, from every protocol I can find.


It is also doable with pH higher than 2, and I observed maybe slightly quicker reaction, but when you raise pH past 2, quite a bit of base metals hydroxides can come out of solution during the process. You can eventually wash the precipitate with some acid to get rid of them, but I prefer to run at pH 2 and consistently getting 99+% Pd.


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## orvi (Oct 10, 2022)

Alondro said:


> The scientific papers on the process I read suggested as high a purity as 99.7% was possible when reduction conditions were well-controlled and optimized.
> 
> But getting as much silver out as possible first from mixed solutions was very important.


Yeah, silver need to be eliminated beforehand, as it will also drop with Pd. This is the whole culprit of the process, because HCl or NaCl precipitation of AgCl always drag Pd into precipitate and this is never washed free of Pd. My experience is between 0,2-0,7% Pd stay in AgCl, if feed was AgPd30 alloy. Not terribly much, but it need additional processing, which is extra step - redissolving in nitric and scavenging traces of Pd with DMG. I don´t know how well silver cell will cope with this Pd ammount in silver tho - never ran the Pd contamined raw silver through.

Do you have these documents somewhere ? I will like to read about it, if you can share them


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## sayf (Oct 10, 2022)

orvi said:


> Do you have these documents somewhere ? I will like to read about it, if you can share them


Same here, i looked in the researchgate but found nothing useful


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## sayf (Oct 10, 2022)

orvi said:


> Do you have these documents somewhere ? I will like to read about it, if you can share them


Same here, i looked in the researchgate but found nothing usefu


orvi said:


> It is also doable with pH higher than 2, and I observed maybe slightly quicker reaction, but when you raise pH past 2, quite a bit of base metals hydroxides can come out of solution during the process. You can eventually wash the precipitate with some acid to get rid of them, but I prefer to run at pH 2 and consistently getting 99+% Pd.


Can you give me detailed steps for the process orvi , is it as follows : you raise the ph up to a point betweeb 2 and 4 then you bring the solution to a boil then you start adding the *form*ic acid, am i correct ?

Edit for correct spelling in bold


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## Alondro (Oct 11, 2022)

sayf said:


> Same here, i looked in the researchgate but found nothing useful


I had only written down the summarized protocol. All the search results now are focusing on using palladium and formic acid for hydrogen production or reducing organic compounds and nitrate.

I can't find the old links because the searches have hundreds of these new papers using the same chemicals for totally different processes!

I did manage to find one from Sciencedirect which mentions formic acid as part of the recovery process, but it's not the article where formic acid reduction was the core subject, optimizing the reagents and conditions: https://www.sciencedirect.com/science/article/abs/pii/S0926860X05009075

It does show an optimized and cost-effective process for DISSOLVING Pd in HCl-H2O2, with the exact conditions for this! Nitric isn't required! 7% HCl, 5% H2O2, 10 to 1 ratio of liquid to solid material, heat to 60C for 2 hours, and it was all dissolved!

This paper got 98% purity, with a near complete (>99%) recovery of Pd from the scrap material.


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## orvi (Oct 11, 2022)

sayf said:


> Same here, i looked in the researchgate but found nothing usefu
> 
> Can you give me detailed steps for the process orvi , is it as follows : you raise the ph up to a point betweeb 2 and 4 then you bring the solution to a boil then you start adding the *form*ic acid, am i correct ?
> 
> Edit for correct spelling in bold











AgPd contacts refining


As the material I recieved few days ago is very nice and illustrative, I decided to share my refining venture of the lot. 85,5 grams of AgPd contact cuttings, on ferrous carrier (altough looks like copper, it is only copper plated ferrous alloy). Beads itself are 29-30% Pd by weight. So I...




goldrefiningforum.com


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## Yggdrasil (Oct 11, 2022)

Alondro said:


> I had only written down the summarized protocol. All the search results now are focusing on using palladium and formic acid for hydrogen production or reducing organic compounds and nitrate.
> 
> I can't find the old links because the searches have hundreds of these new papers using the same chemicals for totally different processes!
> 
> ...


If my memory serves me right I seem to remember something about Formic acid or maybe Sodium formate in Hokes book too.
I seem to remember it was hard to find when I tried to dig it up again though.


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## FrugalRefiner (Oct 11, 2022)

Chapters X and XIV, mainly XIV.

Dave


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## Alondro (Oct 11, 2022)

Yggdrasil said:


> If my memory serves me right I seem to remember something about Formic acid or maybe Sodium formate in Hokes book too.
> I seem to remember it was hard to find when I tried to dig it up again though.


Looks like it'll be up to us to optimize the protocol ourselves! We have the basic protocol, at least. It's just a matter of testing variations to see what works best.


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## Yggdrasil (Oct 12, 2022)

FrugalRefiner said:


> Chapters X and XIV, mainly XIV.
> 
> Dave


Thanks Dave 
I have never used it, but rereads it from time to time.


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## orvi (Oct 12, 2022)

Alondro said:


> Looks like it'll be up to us to optimize the protocol ourselves! We have the basic protocol, at least. It's just a matter of testing variations to see what works best.


Above, I posted link to my AgPd alloy on FeCu carriers - refining via formic acid/NaOH. Not perfect, but I obtained 99.4 % Pd at the end. It isn´t that complicated at all, one thing that you really need is patience and good hood, due to possibility of CO formation from partial oxidation of formic acid.

Additionally, it is wise to wash Pd sponge with 5-10% H2SO4 to clean it from possible entrapped base metal hydroxides, that could be dragged with Pd when precipitating.

Higher you go with pH, I found the reaction somewhat quicker, but I will advise to stick to pH around 2. Remove all silver diligently beforehand, as it will also co-precipitate with Pd as metallic Ag.
I do not have experience with formate reduction of other PGMs or their mixtures tho. So I do not have first hand experience of eg PtPd solutions reduction. Apparently, it should work fine.

Be careful with Pd microparticles, they can be pretty high fire hazard if somewhere close flammable gasses or solvents, espetially hydrogen or nat gas. Pd and Pt are catalytic, be aware of this fact. Carefully wipe all of the residues with wet towel and store these wipes wet before incinerating and recovering values. Just to be sure


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## Alondro (Oct 13, 2022)

orvi said:


> Above, I posted link to my AgPd alloy on FeCu carriers - refining via formic acid/NaOH. Not perfect, but I obtained 99.4 % Pd at the end. It isn´t that complicated at all, one thing that you really need is patience and good hood, due to possibility of CO formation from partial oxidation of formic acid.
> 
> Additionally, it is wise to wash Pd sponge with 5-10% H2SO4 to clean it from possible entrapped base metal hydroxides, that could be dragged with Pd when precipitating.
> 
> ...


I do most of my refining outside, well away from the house! Only HCl wash steps are in a more enclosed space.


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## sayf (Oct 19, 2022)

orvi said:


> Above, I posted link to my AgPd alloy on FeCu carriers - refining via formic acid/NaOH. Not perfect, but I obtained 99.4 % Pd at the end. It isn´t that complicated at all, one thing that you really need is patience and good hood, due to possibility of CO formation from partial oxidation of formic acid.
> 
> Additionally, it is wise to wash Pd sponge with 5-10% H2SO4 to clean it from possible entrapped base metal hydroxides, that could be dragged with Pd when precipitating.
> 
> ...


So orvi i did read the whole thread of yours, thats a beautiful bead of palladium tbh.
You mentioned that copper and Fe can be eliminated with diluted nitric acid and small additions of sulphuric acid. In my case the mlccs i have are about 4 kilo grams of mixed types(old school mlccs and new ones) and i finely powdered them and got rid of the copper legs using a fine mesh 
So now the palladium foils are finely grounded. The question now is :
Will the diluted nitric that is used to get rid of copper dissolve some of the palladium because its finely powdered ?


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## orvi (Oct 19, 2022)

sayf said:


> So orvi i did read the whole thread of yours, thats a beautiful bead of palladium tbh.
> You mentioned that copper and Fe can be eliminated with diluted nitric acid and small additions of sulphuric acid. In my case the mlccs i have are about 4 kilo grams of mixed types(old school mlccs and new ones) and i finely powdered them and got rid of the copper legs using a fine mesh
> So now the palladium foils are finely grounded. The question now is :
> Will the diluted nitric that is used to get rid of copper dissolve some of the palladium because its finely powdered ?


Yes, it will. I hate wet route for ceramic based materials, as it is never complete and very tiring. And you need to get rid of silver firstly, so nitric leach is necessary. But it probably won´t recover all values. So after that, you will need to continue with AR.


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## sayf (Oct 19, 2022)

orvi said:


> Yes, it will. I hate wet route for ceramic based materials, as it is never complete and very tiring. And you need to get rid of silver firstly, so nitric leach is necessary. But it probably won´t recover all values. So after that, you will need to continue with AR


Then ill go directly with concentrated nitric acid and ill give high heat for 2 to 3 hours
Tin will be turned to insoluble metastannic acid and most of the nickel will not be dissolved
Mostly Silver copper and palladium will be in the solution.
After filtration ill precipitate silver with enough amount of hcl
Then collect my silver and precipitate palladium with formic acid using your way.
You mentioned that copper will not precipitate if the ph is around 2


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## Yggdrasil (Oct 20, 2022)

sayf said:


> Then ill go directly with concentrated nitric acid and ill give high heat for 2 to 3 hours
> Tin will be turned to insoluble metastannic acid and most of the nickel will not be dissolved
> Mostly Silver copper and palladium will be in the solution.
> After filtration ill precipitate silver with enough amount of hcl
> ...


Concentrated Nitric will dissolve Pd.
If you have Tin use HCl first, it will dissolve the Tin and most if not all the Nickel.
Filter it and wash the powder well, roast them and then go for Nitric, but use dilute Nitric, to reduce dissolving too much Pd.


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## orvi (Oct 20, 2022)

Yggdrasil said:


> Concentrated Nitric will dissolve Pd.
> If you have Tin use HCl first, it will dissolve the Tin and most if not all the Nickel.
> Filter it and wash the powder well, roast them and then go for Nitric, but use dilute Nitric, to reduce dissolving too much Pd.


Yeah, nitric dissolve bare, exposed Pd, but from my experience, platelets of ultrafine foils of Pd between layers of ceramic are very difficult to strip of values completely with nitric alone. That is why we completely abandoned "wet route" for MLCCs in classical terms of soaking the vigorously stirred powdered MLCCs in ntric. Without decomposition of ceramic matrix, it took ages for them to dissolve, even in hot solutions, and ceramics hold the values adsorbed onto the surface. HCL does much better job in destructing ceramic matrix, so AR leach is in my opinion necessary as second step.*

Owltech has relatively recently posted great video on processing old Bulgarian MLCCs by "wet route", altough he dissolve ceramic matrix firstly with conc. HCL - which also took with it base metals from the solder, and also somehow copper legs too. Mystery to me how copper can be dissolved in just HCL, but it is clearly happening in the conditions used, together with prolonged boiling. Important to say, if base metals dissapear from the solution, HCL also leach some Pd into the solution just by itself. So testing with stannous should be advised.

*edit for clarification: not all types of ceramic are decomposed in hot HCL or AR. Easiest to disintegrate and eventually dissolve are BaTiO3 ceramics found in old MLCCs. Altough some modern types are also attacked.


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## Yggdrasil (Oct 20, 2022)

I agree, but Sayf wanted to go directly to concentrated Nitric and then in retrospect deal with the meta stannic acid.
That was the reasoning for my reply.
Edit for spelling.


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## kurtak (Oct 20, 2022)

orvi said:


> Owltech has relatively recently posted great video on processing old Bulgarian MLCCs by "wet route", altough he dissolve ceramic matrix firstly with conc. HCL



Orvi - *could you provide a link to that video*

I have a hard time believing you can dissolve ceramic with HCl 

I have leached a lot of ceramics over the years (MLCCs, CATs, CPUs, ICs) & I have never seen HCl dissolve the ceramic - ever if very finely ground to powder

Are you sure he is not using HF (Hydrofluoric acid) 

HF would certainly dissolve ceramic - especially if ground very fine

BUT - holy crap - what an *extremely dangerous *way to get rid of ceramic

HF is one (if not the) most dangerous acids on the planet

Kurt


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## Alondro (Oct 20, 2022)

kurtak said:


> Orvi - *could you provide a link to that video*
> 
> I have a hard time believing you can dissolve ceramic with HCl
> 
> ...


I've actually encountered this with SOME ceramic MLCCs. The ceramic appears to be pure titanium oxide, and not as solid as other MLCCs. When broken, it has a 'powdery' look and not glassy. A few days in concentrated HCl, and those crumbled into white powder. Others of the harder, glassier type stayed intact. They didn't dissolve, but they did completely fall apart. So any metal layers inside would clearly also have been dissolved. 

But since picking those out of a big batch is rather absurd, better to just smash them all up in the first place!


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## orvi (Oct 20, 2022)

kurtak said:


> Orvi - *could you provide a link to that video*
> 
> I have a hard time believing you can dissolve ceramic with HCl
> 
> ...




I should say first that my previous post was maybe not clear enough, so I clarify what I wanted to say. Of course, you are right, not many ceramics can be dissolved in HCL. 
In the video, Owltech disintegrated and eventually dissolved the ceramics from old MLCCs, but these are mainly barium titanate ceramics. Which disintegrate relatively easily in hot strong HCL solution. At least, barium is leached out as barium chloride (very nasty, but easily treated waste stream...) and rest of titanium oxohydroxide, which can be sometimes undissolved, is very porous and easily crushed even with glass rod directly in the beaker. 

Also some types of modern MLCCs does disintegrate slowly in HCL, but I do not know precise compositions of these ceramics, as I didn´t work with them too often.

I mentioned it just as an option. I did performed several experiments with old types of MLCCs for the possibility of processing them by this wet route, but we sticked to the classic smelting due to hassle with lots of waste liquids and to the end - partial dissolution of PGMs from foils in large quantity of HCL (impractical). But I must admit, it is spectacular to watch how ceramic spreads out and leave the PGM foils/leafs in the acid  After sucessful dissolution of ceramics, all space in the liquid is occupied by foils. Replacing the leachate with fresh HCL, heating and addition of nitric - vigorous reaction (large surface area) and after two or so minutes, bloody red liquid appear... Never gets old  I will do this (altough not the most efficient process) from time to time on small batches just for my own "pleasure" to watch this  very colorful process. Leachate from ceramics is usually purple/blueish in colour (titanous chloride ? or PGM nanoparticles from dissolving solder... we do not precisely know), but when it is left exposed to the air, it will turn green due to dissolved copper from legs. Ceramics are milky white, and then AR dissolution of foils bloody red


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## sayf (Oct 20, 2022)

Yggdrasil said:


> Concentrated Nitric will dissolve Pd.
> If you have Tin use HCl first, it will dissolve the Tin and most if not all the Nickel.
> Filter it and wash the powder well, roast them and then go for Nitric, but use dilute Nitric, to reduce dissolving too much Pd.


Hi and thanks for your reply, i meant there that am gonna skip the step of base metals leaching, instead ill go directly to hot concentrated nitric acid to leach palladium and all other base metals , in this case tin will be turned into metastannic acid and ill get rid of it using the filtration so at the end of the process there will be copper, palladium, and silver in the solution (since nickel is insoluble in concentrated nitric acid)
Silver will be precipitated by hcl then the Solution is filtered to have mostly copper palladium solution 
after that ill adjust the PH to a value between 2and3 to precipitate the palladium by formic acid 

After this process is done ill go to aqua regia to make sure that all the values are leached completely as suggested by orvi


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## Yggdrasil (Oct 21, 2022)

sayf said:


> Hi and thanks for your reply, i meant there that am gonna skip the step of base metals leaching, instead ill go directly to hot concentrated nitric acid to leach palladium and all other base metals , in this case tin will be turned into metastannic acid and ill get rid of it using the filtration so at the end of the process there will be copper, palladium, and silver in the solution (since nickel is insoluble in concentrated nitric acid)
> Silver will be precipitated by hcl then the Solution is filtered to have mostly copper palladium solution
> after that ill adjust the PH to a value between 2and3 to precipitate the palladium by formic acid
> 
> After this process is done ill go to aqua regia to make sure that all the values are leached completely as suggested by orvi


Most members here goes to great length to avoid meta stannic acid. 
It’s not something to just filter. 
It is on the verge of not filterable.
And since a soak in HCl will solve the problem quite quickly, I’d still do that first.
But it is up to you how you decide to run it.


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## sayf (Oct 22, 2022)

Yggdrasil said:


> Most members here goes to great length to avoid meta stannic acid.
> It’s not something to just filter.
> It is on the verge of not filterable.
> And since a soak in HCl will solve the problem quite quickly, I’d still do that first.
> But it is up to you how you decide to run it.


Yeah i already followed your advice, they were in HCL, and diluted nitric is the next step to get rid of copper, iron, and hopefully nickel, but tbh am worried that (20%) diluted nitric will dissolve lot of the palladium since the MLCCs are finely powdered.


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## sayf (Oct 25, 2022)

orvi said:


> Yeah, nitric dissolve bare, exposed Pd, but from my experience, platelets of ultrafine foils of Pd between layers of ceramic are very difficult to strip of values completely with nitric alone. That is why we completely abandoned "wet route" for MLCCs in classical terms of soaking the vigorously stirred powdered MLCCs in ntric. Without decomposition of ceramic matrix, it took ages for them to dissolve, even in hot solutions, and ceramics hold the values adsorbed onto the surface. HCL does much better job in destructing ceramic matrix, so AR leach is in my opinion necessary as second step.*
> 
> Owltech has relatively recently posted great video on processing old Bulgarian MLCCs by "wet route", altough he dissolve ceramic matrix firstly with conc. HCL - which also took with it base metals from the solder, and also somehow copper legs too. Mystery to me how copper can be dissolved in just HCL, but it is clearly happening in the conditions used, together with prolonged boiling. Important to say, if base metals dissapear from the solution, HCL also leach some Pd into the solution just by itself. So testing with stannous should be advised.
> 
> *edit for clarification: not all types of ceramic are decomposed in hot HCL or AR. Easiest to disintegrate and eventually dissolve are BaTiO3 ceramics found in old MLCCs. Altough some modern types are also attacked.





Yggdrasil said:


> Most members here goes to great length to avoid meta stannic acid.
> It’s not something to just filter.
> It is on the verge of not filterable.
> And since a soak in HCl will solve the problem quite quickly, I’d still do that first.
> But it is up to you how you decide to run it.




Hi, i started the process and followed your steps , tin was firstly remobed by hcl and after several washes i put mlccs in diluted nitric 20% until no clear reaction is happening.
After that the mlccs were put in concentrated 70% nitric on 80 Celsius temperature and left there for 4 hours , and of course the fumes were condensated using cold water
Any ways i filtered the nitric and added HCL and silver was filtered

I then added about 50 milliliters of formic acid to the solution and start adding caustic soda to get a PH value around 2 then i stopped the whole process because i got this fluffy precipitate all around the luquid at PH between 2 and 3
So is this normal ?
Should i proceed to the next step which is heating the solution or something is wrong
Thank you


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## Yggdrasil (Oct 25, 2022)

sayf said:


> Hi, i started the process and followed your steps , tin was firstly remobed by hcl and after several washes i put mlccs in diluted nitric 20% until no clear reaction is happening.
> After that the mlccs were put in concentrated 70% nitric on 80 Celsius temperature and left there for 4 hours , and of course the fumes were condensated using cold water
> Any ways i filtered the nitric and added HCL and silver was filtered
> 
> ...


I have never used the Formic acid reduction.
The way you do it do not correspond of how I have seen it or read about it.
I think Sreetips show it in one of his videos.
And I think the precipitate should be dense black/grey powder.

Edit to add:
I found a nice video from Owltech showing the formic acid reduction.


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## sayf (Oct 25, 2022)

Yggdrasil said:


> I have never used the Formic acid reduction.
> The way you do it do not correspond of how I have seen it or read about it.
> I think Sreetips show it in one of his videos.
> And I think the precipitate should be dense black/grey powder.
> ...



Hi, i think i followed the way that orvi used in his thread


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## goldshark (Oct 26, 2022)

Just a quick note on ceramics. you almost have to assay them to determine wether they are high Alumina, high Silica, Titanium composites, etc., before trying to dissolve in the appropriate acid (s). Plus some hybrids I am not familiar with. Figure out the metal/ceramics logistic to determine which is the economical route.


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## Yggdrasil (Oct 26, 2022)

sayf said:


> Hi, i think i followed the way that orvi used in his thread


Did you watch Owltech’s video?


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## sayf (Oct 26, 2022)

Yggdrasil said:


> Did you watch Owltech’s video?


Yes i did, but he didnt get the same fluffy precipitate i got when adjusting the PH


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## Yggdrasil (Oct 26, 2022)

sayf said:


> Yes i did, but he didnt get the same fluffy precipitate i got when adjusting the PH


He got the right thing.
I haven't checked his video yet.
But I think according to the information in Hokes book, you need to adjust the pH first and then add the PM bearing solution into the boiling formic acid.


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## Yggdrasil (Oct 26, 2022)

sayf said:


> Yes i did, but he didnt get the same fluffy precipitate i got when adjusting the PH


I'm not entirely sure what you did, but he adjusted the pH until the Pd precipitated as an Hydroxide I guess, then he added the formic acid and started boiling/simmering until the liquid was crystal clear.
This increases the chance of bringing down contamination, since he took the pH all the way up to 4.
Have you read the writings on formate reduction in Hokes book?


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## sayf (Oct 26, 2022)

Yggdrasil said:


> I'm not entirely sure what you did, but he adjusted the pH until the Pd precipitated as an Hydroxide I guess, then he added the formic acid and started boiling/simmering until the liquid was crystal clear.
> This increases the chance of bringing down contamination, since he took the pH all the way up to 4.
> Have you read the writings on formate reduction in Hokes book?


In owl case the solution was mainly containing palladium , in my case i think i have nickel copper maybe some iron.
Orvi in his process put the formic first then took the ph up to 2 then he simmered the solution for 2to3 hours


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## Yggdrasil (Oct 26, 2022)

sayf said:


> In owl case the solution was mainly containing palladium , in my case i think i have nickel copper maybe some iron.
> Orvi in his process put the formic first then took the ph up to 2 then he simmered the solution for 2to3 hours


Have you read the process in Hokes book?


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## sayf (Oct 26, 2022)

Yggdrasil said:


> Have you read the process in Hokes book?


I read lot of it but tbh i havnt read the formic part as i remember its somewhere in chapter 6


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## Yggdrasil (Oct 26, 2022)

sayf said:


> I read lot of it but tbh i havnt read the formic part as i remember its somewhere in chapter 6


It’s easy to find, I just reread it.
The approach is quite different and she uses Ammonia and neutral conditions.


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## sayf (Oct 26, 2022)

Yggdrasil said:


> It’s easy to find, I just reread it.
> The approach is quite different and she uses Ammonia and neutral conditions.


I nutralized the whole solution to a ph 7, filtered it and dissolved every thing again in HCL , i found some silver chloride and got rid of it . Any ways i used sodium carbonate this time to raise the PH and the fluffy precipitate that i showed you in the picture hasnt formed this time . I followed the video of owl tech carefully and reached a PH between 3and4. And a light brown precipitate has formed this time. 
Any ways i added 50 ml of formic acid while giving heat to the solution and unluckily nothing happen no color change and no black Pd mirror has formed in an hour of gentle boiling so i am expecting that the formic acid may has a problem.


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## Yggdrasil (Oct 26, 2022)

sayf said:


> I nutralized the whole solution to a ph 7, filtered it and dissolved every thing again in HCL , i found some silver chloride and got rid of it . Any ways i used sodium carbonate this time to raise the PH and the fluffy precipitate that i showed you in the picture hasnt formed this time . I followed the video of owl tech carefully and reached a PH between 3and4. And a light brown precipitate has formed this time.
> Any ways i added 50 ml of formic acid while giving heat to the solution and unluckily nothing happen no color change and no black Pd mirror has formed in an hour of gentle boiling so i am expecting that the formic acid may has a problem.


Hokes page 156-160 is where it is.
Formic acid decomposes so if its old it may have decomposed too much.
Are you sure you have Pd in solution??


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## sayf (Oct 26, 2022)

Yggdrasil said:


> Hokes page 156-160 is where it is.
> Formic acid decomposes so if its old it may have decomposed too much.
> Are you sure you have Pd in solution??


Well, about 4 kg of mixed mlccs they should have Pd.
Ill read the pages and get back to you with any news . Thank u


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## Yggdrasil (Oct 26, 2022)

sayf said:


> Well, about 4 kg of mixed mlccs they should have Pd.
> Ill read the pages and get back to you with any news . Thank u


They might not have, have you tested them withe either stannous or DMG?


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## sayf (Oct 26, 2022)

Yggdrasil said:


> They might not have, have you tested them withe either stannous or DMG?


Well, i tested the powder with a friends xrf device and got a read of 1% palladium , thats about 40 gram in my 4 kilos of mlcc powder


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## Yggdrasil (Oct 26, 2022)

sayf said:


> Well, i tested the powder with a friends xrf device and got a read of 1% palladium , thats about 40 gram in my 4 kilos of mlcc powder


It does not mean that you have managed to get it into solution.
Both stannous and DMG will show that.


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## eaglekeeper (Oct 26, 2022)

Yggdrasil said:


> They might not have, have you tested them with either stannous or DMG?



Testing your solutions very important...I test at every step. Many things can change during the process and the only way to know where your PM's are is to test.

It takes *a lot *of sodium carbonate to get the PH up..... that fluffy stuff *might be* excess sodium carbonate. Sodium hydroxide would have been a better choice...in my opinion. You can use ammonia, but I generally don't keep ammonia in my lab...for safety reasons. 

After you adjusted the PH and added formic acid....how long did you boil the solution, it sometimes takes awhile. Last time I used formic acid I had to boil it for 2 hours before it started to clear up.


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## sayf (Oct 27, 2022)

eaglekeeper said:


> Testing your solutions very important...I test at every step. Many things can change during the process and the only way to know where your PM's are is to test.
> 
> It takes *a lot *of sodium carbonate to get the PH up..... that fluffy stuff *might be* excess sodium carbonate. Sodium hydroxide would have been a better choice...in my opinion. You can use ammonia, but I generally don't keep ammonia in my lab...for safety reasons.
> 
> After you adjusted the PH and added formic acid....how long did you boil the solution, it sometimes takes awhile. Last time I used formic acid I had to boil it for 2 hours before it started to clear up.


The solution hasnt darkened and the solution has a brown precipitate even after adding the formic acid and boiling for 1 hour


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## Yggdrasil (Oct 27, 2022)

sayf said:


> The solution hasnt darkened and the solution has a brown precipitate even after adding the formic acid and boiling for 1 hour


Test it with either Stannous or DMG.
Make sure your Formic acid is good.

As you saw Owltech pushed the pH up until he had a clear defined "hydroxide" and then added the formic acid and started boiling.
Hokes describes how to use precipitated salts in a near neutral conditions, so obviously there are more ways to skin a cat, even in this realm.


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## sayf (Oct 27, 2022)

Yggdrasil said:


> Test it with either Stannous or DMG.
> Make sure your Formic acid is good.
> 
> As you saw Owltech pushed the pH up until he had a clear defined "hydroxide" and then added the formic acid and started boiling.
> Hokes describes how to use precipitated salts in a near neutral conditions, so obviously there are more ways to skin a cat, even in this realm.


As you see in the pic below i have a clear brown hydroxide precipitate but its bot darkening after adding the formic and boiling


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## Yggdrasil (Oct 27, 2022)

sayf said:


> As you see in the pic below i have a clear brown hydroxide precipitate but its bot darkening after adding the formic and boiling


Since you have no test saying you have Pd in solution it is hard to say what has happened.
Re acidify it and make sure the hydroxides are dissolved again.
Test it with either stannous or DMG.

Then start over. 
How old is your Formic acid?


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## sayf (Oct 27, 2022)

Yggdrasil said:


> Since you have no test saying you have Pd in solution it is hard to say what has happened.
> Re acidify it and make sure the hydroxides are dissolved again.
> Test it with either stannous or DMG.
> 
> ...


Ok ill do that
Its 1 year and a half old


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## Yggdrasil (Oct 27, 2022)

sayf said:


> Ok ill do that
> Its 1 year and a half old


Might be ok, I have no idea about the decomposition rate.


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## sayf (Oct 27, 2022)

Yggdrasil said:


> Since you have no test saying you have Pd in solution it is hard to say what has happened.
> Re acidify it and make sure the hydroxides are dissolved again.
> Test it with either stannous or DMG.
> 
> ...


When i reacidified the solution to minimum ph and added some formic then started adding the caustic soda a black cloud has formed as shown


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