Problems in platinum recovery

[slsmp40]

In what form does the Pd precipitate?

Sodium chloride in AR should not participate silver chloride under any circumstances. It would be created from the chloride in the hcl alone.

 

[slsmp40]

The most economical way to handle this if you absolutely had to work with the copper diluted alloy would be to completely dissolve it in AR and then drop the gold. If smb was used to drop the gold you would need to let the solution rest in the open atmosphere for a few days to make sure the sulfur containing gases were gone from the solution.
Then cement the values so you can get a clean solution to work with when you add Ar again.

 

[Yggdrasil]

Sodium chloride in AR should not participate silver chloride under any circumstances. It would be created from the chloride in the hcl alone.

Absolutely true.
I was so focused on the claim of precipitating the Pd that I completely overlooked the AgCl claim.

 

[orvi]

I should point out that you really should not be drying the ammonium hexachloroplatinate like that. It is best to always handle it damp, with full PPE and preferably in a filter box. Then take a shower after!

That admonition aside, the color of the ammonium hexachloroplatinate you have shown and talked about indicates contamination. It's highly suggested to either dissolve the salt in aqua regia (or otherwise remove the ammonium cation) and complete a hydrolytic refining from oxidizing conditions, as described in 4metals other thread titled Bromate Hydrolysis. You do not need to use bromate, chlorine and caustic soda are use industrially. Bromate just happens to give a better result.

the iridate salt, which comes down substantially completely with the platinum from highly oxidized solutions, will darken your platinum precipitate orange to red. Palladium can also do this, and is far more likely.

Palladium co-precipitation was also my first bet.

 

[orvi]

maybe you mean that they co-precipitate when you add salt to the solution of Pd and Ag in nitric acid (not in AR). I seem to remember that it also happened to me on one occasion.
thank you very much kurt and 4metals.
There were some things I didn't know like not using AR if PGMs are not the main metal, or that PGMs don't precipitate well in dilute solutions. Also the silver 10 times higher than the Pt so that it drags everything towards the silver part.
You are not aware of what a tremendous pleasure it is to read and learn from you.
I will reconsider everything you have told me and see again what path to take.
I come across platinum tunings more often than I would like and sometimes I don't understand why sometimes it turns out well and other times not so much.
So thanks again for providing your vision.
I take this opportunity to ask another question. I have noticed that sometimes the precipitate after adding ammonium chloride is yellow, other times orange, and even once I recovered it from a solution that had iridium it came out red. From what I have read, this depends on the temperature at which it is formed. But as I understand it, iridium precipitates black. The red I got was carmine red, it didn't look like a mixture of the orange powder and black. I leave a photo of the normal one, and that red that I tell you about. In case you can provide some valuable information through your experience.
Thanks guys

all images are ammonium hexachloroplatinate

With amounts of platinum and palladium in material, I would suggest (as other experienced members suggested) to go for the gold and accumulate PGM residue for later processing. Working with PGMs is much more complex and tedious task, and it is best to combine the leftovers from multiple runs to save time and your sanity

In PGM refining, ammonium hexachloroplatinate is something like silver chloride for refiners If you really do not need to produce it, you avoid it and refine with other methods. If you do not happen to have nice tube furnance equipped with hydrogen cylinder for complete and convenient reduction to platinum sponge of course

With this feed you have, I will probably go with dissolution in AR as you did, AgCl bulk filtration, then gold precipitation.
Leftover liquid containing PGMs would be then cemented (either with appropriate amount of iron or with copper) to concentrate values (this will allow you to skip evaporation) as metallic powders.

And from there, you can either process them (nicely concentrated feed = easy to do) either cumulatively or individually (each batch separately).

If you need to somehow clean the PtPd and resolve it to Pt and Pd part, good and easy method to use is to de-NOx the solution to get rid of any leftover oxidizing species and precipitate palladium with ascorbic acid. Silver and also some copper will follow, but co-precipitation of platinum is minimal. It needs pH adjustment (which also usually lead to one necessary filtration of eventual hydroxides precipitate) to around 1 to work OK. There are threads discussing the ascorbic reduction of Pd on the forum. Relatively Pt free palladium powder will be obtained, and liquid will contain reduced Pt(II) species alongside with majority of base metals.

------------
Maybe I missed it, but is there a reason why you isolate platinum and palladium from feeds ? From my experience, if you don´t produce high purity added value products from PGMs (like catalysts, pure PGM salts, pure PGM metal wires/sheets etc.), I see no benefit in refining these quantities of metals yourself. Melt the enriched PGM leftover from cementation (this should have very decent PGM content) and sell it to larger PGM processors. In small quantities, your time as employee can be sometimes more valuable than money you can make selling 99% pure PGMs.

 

[Abdoulapapatte]

hello I just put my two cents here, I read you and I learned a lot, personally I never went through aqua regia if AG Above 7%, too many jokes in the past, too much loss and too much processing time afterwards (to be avoided and prohibited).Nitric acid dissolves platinum in small concentrations ????
oh good??

why then do I find the exact grammage even when it's 3gr per kg?? especially in silver blocks that I etch with nitric 65%?

Unless I'm not washing properly, which is possible because I was never allowed to breathe in boulor, I find that with NH4Cl I usually get pure platinum at 996.5/1000. never 999.9 (DAMN!)

for my part and fans of your case, I would have :
1) passage HNO3 -----> Ag and Pd degage

2) filtration -----> Ag/Pd filtrate / retained solid: Au/Pt

3) The filtrate would then be treated in several ways depending on your equipment:

a) precipitation on Cu -----> melting ----> shot blasting-> Ag cell
Ag recovery in 999.9 and Pd recovery in “sludge”.
I'd do a silver cell electrolyte test especially if green tint, if pd present then Dmg and recovery.
to finish, sponge and pd sludge in AR----> precipitation on Cu or zinc powder works very well.

b) Add HCL OR NaCl ---->Ag recover in agcl form ----> Naoh---->glucose----> Ag 999.9 IF rinse well and compress after each wash, to avoid precipitate of Agcl you have to mix several times, its structure changes and it becomes finer, you have to let it rest and filter it, it is important to be meticulous.





image way b)



Pd solution remains ------> Cu precipitation, OR DMG or wholtech method.

4) Coming back to the Au/Pt solid not attacked by HNO3, I'd like to point out that platinum is never attacked in my laboratory, perhaps because I always add enough H2O to cover the alloy to be attacked before adding the nitric acid, perhaps because the nitric acid dissolved in this way doesn't attack it (something to think about).
Take your solids, wash well with distilled H2O several times.
Once well washed, I check for any trace of Agcl still present by adding a little Hcl to the distilled water I used to wash the remaining solids. If Agcl is still present, wash again with hot water.

5) passage of solids in AR, another small detail,
I never prepare aqua regia 1/4 HNO3--3/4 HCL (c'est bon pour les durs à cuire) ici on recherche la finesse, l'élégance et la clarté. Bref, soyez un vrai gentleman cambrioleur.
SO put enough HCL 37% (muratic acid) that you think you need, and THEN add little by little HNO3 repeatedly, until complete dissolution.

SO put enough HCL 37% (muratic acid) that you think you need, and THEN add HNO3 little by little repeatedly, until the solids are completely dissolved. Why I do this, to simply avoid having to denox HNO3. I therefore approach the stoichiometric quantities

6) After that, nothing could be simpler when you find yourself dear friends with your liquor containing dissolved Au and Pt, you can therefore proceed in 2 different steps:


a) ajouter du sulfate de fer (II = vert) pour précipiter l'Au----> filtration----> lavage avec HCL 37%-- deuxième filtration -----> lavage à l'eau distillée ----> séchage ---> fonte. L'Au est sorti OUI !!!!!



There will therefore only be the platinum left and you can precipitate it with ammonium chloride, before precipitating it you can also add hydrochloric acid, which you used to rinse your gold, in fact it sometimes happens that a little platins follow Au, it is therefore found in hcl that you used to wash it.


To turn your platinum sponge into metal you can either heat it delicately, slowly to avoid losing any, then once it is very black, melt it, or redissolve it and this time precipitate it with formic acid.


here is the appearance of my sponge, 996.5/1000

as I do not like to lie and I love to share my discoveries it is often accompanied by results in order to prove the veracity of my results and what is so lacking in your forum, people put forward hypotheses without controlling their results .

small contamination Pd Rh because waiting to much time before filtration



my face : always work with security , becareful about Pt et Pd sponge.

I would like to make an interesting remark, there is no one on the forum who has taken the time to explain how to correctly refine platinoids and I find that really shameful, I would like the main speakers to take the time to do so a thread on this subject whether in the patent or library section, I am sure that some have the knowledge, the knowledge and the adequate tools to do it so wait you stop keeping your secrets in a cupboard, we must move forward together, and even if your boss forbids you to do it, break the silence, it is not us who are going to compete with an LBMA or any foundry lost on the other side of the world, so advice to the specialists hiding and not sharing, help us progress

see you

 

[Yggdrasil]

hello I just put my two cents here, I read you and I learned a lot, personally I never went through aqua regia if AG Above 7%, too many jokes in the past, too much loss and too much processing time afterwards (to be avoided and prohibited).Nitric acid dissolves platinum in small concentrations ????
oh good??

why then do I find the exact grammage even when it's 3gr per kg?? especially in silver blocks that I etch with nitric 65%?

Unless I'm not washing properly, which is possible because I was never allowed to breathe in boulor, I find that with NH4Cl I usually get pure platinum at 996.5/1000. never 999.9 (DAMN!)

for my part and fans of your case, I would have :
1) passage HNO3 -----> Ag and Pd degage

2) filtration -----> Ag/Pd filtrate / retained solid: Au/Pt

3) The filtrate would then be treated in several ways depending on your equipment:

a) precipitation on Cu -----> melting ----> shot blasting-> Ag cell
Ag recovery in 999.9 and Pd recovery in “sludge”.
I'd do a silver cell electrolyte test especially if green tint, if pd present then Dmg and recovery.
to finish, sponge and pd sludge in AR----> precipitation on Cu or zinc powder works very well.

b) Add HCL OR NaCl ---->Ag recover in agcl form ----> Naoh---->glucose----> Ag 999.9 IF rinse well and compress after each wash, to avoid precipitate of Agcl you have to mix several times, its structure changes and it becomes finer, you have to let it rest and filter it, it is important to be meticulous.



View attachment 66543
View attachment 66545
image way b)


View attachment 66544
Pd solution remains ------> Cu precipitation, OR DMG or wholtech method.

4) Coming back to the Au/Pt solid not attacked by HNO3, I'd like to point out that platinum is never attacked in my laboratory, perhaps because I always add enough H2O to cover the alloy to be attacked before adding the nitric acid, perhaps because the nitric acid dissolved in this way doesn't attack it (something to think about).
Take your solids, wash well with distilled H2O several times.
Once well washed, I check for any trace of Agcl still present by adding a little Hcl to the distilled water I used to wash the remaining solids. If Agcl is still present, wash again with hot water.

5) passage of solids in AR, another small detail,
I never prepare aqua regia 1/4 HNO3--3/4 HCL (c'est bon pour les durs à cuire) ici on recherche la finesse, l'élégance et la clarté. Bref, soyez un vrai gentleman cambrioleur.
SO put enough HCL 37% (muratic acid) that you think you need, and THEN add little by little HNO3 repeatedly, until complete dissolution.

SO put enough HCL 37% (muratic acid) that you think you need, and THEN add HNO3 little by little repeatedly, until the solids are completely dissolved. Why I do this, to simply avoid having to denox HNO3. I therefore approach the stoichiometric quantities

6) After that, nothing could be simpler when you find yourself dear friends with your liquor containing dissolved Au and Pt, you can therefore proceed in 2 different steps:


a) ajouter du sulfate de fer (II = vert) pour précipiter l'Au----> filtration----> lavage avec HCL 37%-- deuxième filtration -----> lavage à l'eau distillée ----> séchage ---> fonte. L'Au est sorti OUI !!!!!
View attachment 66542


There will therefore only be the platinum left and you can precipitate it with ammonium chloride, before precipitating it you can also add hydrochloric acid, which you used to rinse your gold, in fact it sometimes happens that a little platins follow Au, it is therefore found in hcl that you used to wash it.


To turn your platinum sponge into metal you can either heat it delicately, slowly to avoid losing any, then once it is very black, melt it, or redissolve it and this time precipitate it with formic acid.

View attachment 66539
here is the appearance of my sponge, 996.5/1000

as I do not like to lie and I love to share my discoveries it is often accompanied by results in order to prove the veracity of my results and what is so lacking in your forum, people put forward hypotheses without controlling their results .

small contamination Pd Rh because waiting to much time before filtration
View attachment 66541

View attachment 66540
my face : always work with security , becareful about Pt et Pd sponge.

I would like to make an interesting remark, there is no one on the forum who has taken the time to explain how to correctly refine platinoids and I find that really shameful, I would like the main speakers to take the time to do so a thread on this subject whether in the patent or library section, I am sure that some have the knowledge, the knowledge and the adequate tools to do it so wait you stop keeping your secrets in a cupboard, we must move forward together, and even if your boss forbids you to do it, break the silence, it is not us who are going to compete with an LBMA or any foundry lost on the other side of the world, so advice to the specialists hiding and not sharing, help us progress

see you

Nitric will not touch Pt, unless it is alloyed with Silver.
If you have an alloy with Silver, 1 to10 Pt Silver, the Nitric will dissolve the Pt completely.

 

[Hozzy]

Hi there,

Thanks for sharing your process! The green scab you observed is likely CuCl₂ (Copper(II) chloride), formed due to the high copper content reacting with chloride ions in aqua regia. This can happen if the reaction slows or becomes less acidic over time.

To confirm, dissolve a small amount in water—CuCl₂ is water-soluble and turns the solution green.

Since copper is dominating, it might interfere with dissolving other metals. You could filter the residue and consider removing excess copper (e.g., via cementation with iron) before continuing with platinum and gold recovery.

Let me know if you need further tips!

 

[Yggdrasil]

Hi there,

Thanks for sharing your process! The green scab you observed is likely CuCl₂ (Copper(II) chloride), formed due to the high copper content reacting with chloride ions in aqua regia. This can happen if the reaction slows or becomes less acidic over time.

To confirm, dissolve a small amount in water—CuCl₂ is water-soluble and turns the solution green.

Since copper is dominating, it might interfere with dissolving other metals. You could filter the residue and consider removing excess copper (e.g., via cementation with iron) before continuing with platinum and gold recovery.

Let me know if you need further tips!

On the other hand Copper will not "interfere" with dissolving other metals.
It will consume more Nitric which is true and as long as you dissolve it all it will not cement out the precious metals.
If it is doable or practical, we recommend dissolving the base metals first.
And then go for the precious metals.

 

[100tific]

hello I just put my two cents here, I read you and I learned a lot, personally I never went through aqua regia if AG Above 7%, too many jokes in the past, too much loss and too much processing time afterwards (to be avoided and prohibited).Nitric acid dissolves platinum in small concentrations ????
oh good??

why then do I find the exact grammage even when it's 3gr per kg?? especially in silver blocks that I etch with nitric 65%?

Unless I'm not washing properly, which is possible because I was never allowed to breathe in boulor, I find that with NH4Cl I usually get pure platinum at 996.5/1000. never 999.9 (DAMN!)

for my part and fans of your case, I would have :
1) passage HNO3 -----> Ag and Pd degage

2) filtration -----> Ag/Pd filtrate / retained solid: Au/Pt

3) The filtrate would then be treated in several ways depending on your equipment:

a) precipitation on Cu -----> melting ----> shot blasting-> Ag cell
Ag recovery in 999.9 and Pd recovery in “sludge”.
I'd do a silver cell electrolyte test especially if green tint, if pd present then Dmg and recovery.
to finish, sponge and pd sludge in AR----> precipitation on Cu or zinc powder works very well.

b) Add HCL OR NaCl ---->Ag recover in agcl form ----> Naoh---->glucose----> Ag 999.9 IF rinse well and compress after each wash, to avoid precipitate of Agcl you have to mix several times, its structure changes and it becomes finer, you have to let it rest and filter it, it is important to be meticulous.



View attachment 66543
View attachment 66545
image way b)


View attachment 66544
Pd solution remains ------> Cu precipitation, OR DMG or wholtech method.

4) Coming back to the Au/Pt solid not attacked by HNO3, I'd like to point out that platinum is never attacked in my laboratory, perhaps because I always add enough H2O to cover the alloy to be attacked before adding the nitric acid, perhaps because the nitric acid dissolved in this way doesn't attack it (something to think about).
Take your solids, wash well with distilled H2O several times.
Once well washed, I check for any trace of Agcl still present by adding a little Hcl to the distilled water I used to wash the remaining solids. If Agcl is still present, wash again with hot water.

5) passage of solids in AR, another small detail,
I never prepare aqua regia 1/4 HNO3--3/4 HCL (c'est bon pour les durs à cuire) ici on recherche la finesse, l'élégance et la clarté. Bref, soyez un vrai gentleman cambrioleur.
SO put enough HCL 37% (muratic acid) that you think you need, and THEN add little by little HNO3 repeatedly, until complete dissolution.

SO put enough HCL 37% (muratic acid) that you think you need, and THEN add HNO3 little by little repeatedly, until the solids are completely dissolved. Why I do this, to simply avoid having to denox HNO3. I therefore approach the stoichiometric quantities

6) After that, nothing could be simpler when you find yourself dear friends with your liquor containing dissolved Au and Pt, you can therefore proceed in 2 different steps:


a) ajouter du sulfate de fer (II = vert) pour précipiter l'Au----> filtration----> lavage avec HCL 37%-- deuxième filtration -----> lavage à l'eau distillée ----> séchage ---> fonte. L'Au est sorti OUI !!!!!
View attachment 66542


There will therefore only be the platinum left and you can precipitate it with ammonium chloride, before precipitating it you can also add hydrochloric acid, which you used to rinse your gold, in fact it sometimes happens that a little platins follow Au, it is therefore found in hcl that you used to wash it.


To turn your platinum sponge into metal you can either heat it delicately, slowly to avoid losing any, then once it is very black, melt it, or redissolve it and this time precipitate it with formic acid.

View attachment 66539
here is the appearance of my sponge, 996.5/1000

as I do not like to lie and I love to share my discoveries it is often accompanied by results in order to prove the veracity of my results and what is so lacking in your forum, people put forward hypotheses without controlling their results .

small contamination Pd Rh because waiting to much time before filtration
View attachment 66541

View attachment 66540
my face : always work with security , becareful about Pt et Pd sponge.

I would like to make an interesting remark, there is no one on the forum who has taken the time to explain how to correctly refine platinoids and I find that really shameful, I would like the main speakers to take the time to do so a thread on this subject whether in the patent or library section, I am sure that some have the knowledge, the knowledge and the adequate tools to do it so wait you stop keeping your secrets in a cupboard, we must move forward together, and even if your boss forbids you to do it, break the silence, it is not us who are going to compete with an LBMA or any foundry lost on the other side of the world, so advice to the specialists hiding and not sharing, help us progress

see you

I am fascinated by your explanation, thank you very much. I think your Pt never follows nitric because the amount of silver is not 10 times greater than that of platinum.
Normally I use sodium metabisulfite to precipitate the gold instead of iron sulfate, I suppose it will not significantly affect the result. but what do you think?
I have seen that the method you use to recover silver is electrolytically. I have an electrolytic cell to recover the silver, but we do several recoveries there and when I extract PGMs I like to make each batch individually, I would not like to put those liquids where we put the rest and I would prefer to treat them individually. So the method I will use to separate Ag and Pd in a single batch would be NaCl or HCl to the liquid after the HNO3. I would like to know if, when we add NaCl or HCl to the liquid, Pd and Ag coprecipitate or is it selective for Ag only. Because on one occasion this gave me problems. I tried to separate them and there was no Pd left in the liquid and the AgCl had a pink tone. I think I solved it by adding HNO3 back to the precipitate. I would like to discuss this if anyone has any knowledge.
I am trying to know "the method" to be able to separate precious metals having any alloy. Compiling all information and with the equipment and material I have available.
I have already bought more safety clothing, masks that cover my entire face and jackets. I have also bought copper powder.
I would like to show you how I do it and when I receive all the material and the results I obtain.
Meanwhile I continue studying, I continue reading, all information is welcome, and thank you again.

 

[diclame]

The most economical way to handle this if you absolutely had to work with the copper diluted alloy would be to completely dissolve it in AR and then drop the gold. If smb was used to drop the gold you would need to let the solution rest in the open atmosphere for a few days to make sure the sulfur containing gases were gone from the solution.
Then cement the values so you can get a clean solution to work with when you add Ar again.

What is the point of waiting for smb gases if you are going to precipitate it with copper anyway?
As long as you use good PPE

 

[Yggdrasil]

What is the point of waiting for smb gases if you are going to precipitate it with copper anyway?
As long as you use good PPE

The SMB will drop most if not all the Gold.
It will however still contain minute amounts of Gold and most of the PGMs.
This will be cemented out with Copper.
This will be processed later.
I have not heard that the SO₂ could cause trouble though.

 

[Abdoulapapatte]

Je suis fasciné par votre explication, merci beaucoup. Je pense que votre Pt ne suit jamais le nitrique car la quantité d'argent n'est pas 10 fois supérieure à celle du platine.
Normalement, j'utilise du métabisulfite de sodium pour précipiter l'or au lieu du sulfate de fer, je suppose que cela n'affectera pas de manière significative le résultat. mais qu'en pensez-vous ?
J'ai vu que la méthode que vous utilisez pour récupérer l'argent est électrolytique. J'ai une cellule électrolytique pour récupérer l'argent, mais nous y faisons plusieurs récupérations et lorsque j'extrais des PGM, j'aime faire chaque lot individuellement, je ne voudrais pas mettre ces liquides là où nous mettons le reste et je préfère les traiter individuellement. Donc, la méthode que j'utiliserai pour séparer Ag et Pd dans un seul lot serait NaCl ou HCl au liquide après le HNO3. J'aimerais savoir si, lorsque nous ajoutons NaCl ou HCl au liquide, Pd et Ag coprécipitent ou si c'est sélectif pour Ag uniquement. Parce qu'à une occasion, cela m'a posé des problèmes. J'ai essayé de les séparer et il n'y avait plus de Pd dans le liquide et l'AgCl avait une teinte rose. Je pense que j'ai résolu le problème en rajoutant du HNO3 au précipité. J'aimerais en discuter si quelqu'un a des connaissances.
J'essaie de connaître "la méthode" pour pouvoir séparer les métaux précieux de n'importe quel alliage. En compilant toutes les informations et avec l'équipement et le matériel dont je dispose.
J'ai déjà acheté plus de vêtements de sécurité, des masques qui couvrent tout mon visage et des vestes. J'ai également acheté de la poudre de cuivre.
J'aimerais vous montrer comment je le fais et quand je reçois tout le matériel et les résultats que j'obtiens.
En attendant je continue à étudier, je continue à lire, toutes les informations sont les bienvenues, et merci encore.

ho my god, the perfect woman exists for me she must absolutely be interested in the art of refining, single and max 40 years, if you check all the criteria I marry you tomorrow.
well let's try to be serious for 2 seconds (it's going to be hard) i'll try to be precise chief

1) Between smb and ferrous sulphate, I'd say that FeSo4 is more selective and smb tends to precipitate platinoids, ferrous sulphate should do so less.

It would be good if an expert could confirm this, but I don't think I'm wrong. Someone I know explained to me that she could crack any metal using cyanidation, but I don't know the process in detail.
After a quick search for a video that I'm linking to here, you can see the reagents used and also the order used to refine each of the precious metals in this video here

te TheIPMI chanel youtube is good for you , if pgm's is you're passion .

this guy's can help you about pt pd and rh
here
it uses and experiments« colored powder from Hoock » « go and tcheck » he have 2 channel "chemistry" and "chemistry games"
Here is a last nugget , 4 metal should come here and poke around in the video tutorials, high level for silver conversion, fast easy and clear water, not a disgusting black water (like when you use NaOh and sugar methode) here

For the colored powder, my results for pd in therme of purity are 986/1000 for the first tests (crappy results).

I'm really crazy, searching everywhere on the forum, impossible to find a guy who is even 995/1000 in pt, pd, rh, ir .... in short if you find an interesting thread let me know for my part I have exceeded the ton of gold for a long time, and silver I must be 5 tons. I would have continued in my refinery, but there is a limit to human stupidity, I stopped when my boss wanted me to throw 12,000 litres of used acid into a field. I realised I was finished.

no solution againt stupidity

see you and show me you're result when you work , i think we have same passion like every one here

vincent

 

[Abdoulapapatte]

hello friends, i think you can learn about this guy's and video , 50 video about platinium group metal , you can see color , sponge , equipment and part of process , high level , from china.
work about catalyser car

very interesting

 

[4metals]

They spent a lot of money on some very nice equipment and reactors, most of which I have seen before but one piece impressed me and I did a snip and paste to copy it here. It is in the first video of the series but it shows up elsewhere in the videos as well. What it is, is a mounted horizontal vacuum jug with multiple ports to accept büchner funnels. What I like about it is the convenience of having a permanently connected vacuum source and a drain. I cannot see it clearly but there is probably a rinse water feed to clean it out and another shot from the video's included a large opening port on the end where you could reach in to either rinse better or retrieve solids that somehow ended up in the vessel. The drain likely allows the liquid to transfer on to another process without handling. This one is probably 40-60 liter capacity but with an ability to drain some liquid without removing funnels makes it quite versatile. I would love to know who makes and sells them.

The video is worth looking over slowly and checking out all of the nice equipment. Plenty of work space and likely a single scrap type facility.

 

[Lou]

QVF makes these but you can also get from any well equipped glassblower. These take two of the large pyrex bell jars that get welded end on end. Very nice for saving your back if doing small quantities in a job shop.

 

[100tific]

ho my god, the perfect woman exists for me she must absolutely be interested in the art of refining, single and max 40 years, if you check all the criteria I marry you tomorrow.

Sorry, is this a dating website? I'm 30 and single but we came here to talk about something else more relevant.

I think it is in line with the thread of this post. I find myself facing a new case. Taking into account all the advice you have given me, taking of course the precaution of washing well between each step, and melting the powder after each recovery. I have presented it schematically as follows.
I would like to ask in the last step, although I know I can wash with HNO3 to remove excess Cu, I would like to know how you can estimate the amount of copper powder you will have to add. I don't know if it depends on the platinum that I have in solution, or on the acid capable of reacting.
I also wanted to ask because, I know that to recover the gold from the aqua regia solution, I have to dilute 3 times the amount of liquid I have. But after this comes the recovery of the Pt from the solution, where it is better to have a concentrated liquid. So how can this be compatible? Evaporating this amount of liquid after recovering the gold and after having added SO2 seems too ugly to me. Any suggestions?
*The image shows the initial alloy, it is 82.06g that contains the quantities in parts per thousand of the precious metals indicated. The base metals that I indicate below are in a very small proportion until completing 1000.

I decided to start with AR because the amount of silver is very small and I won't be hindered by those silver chlorides. I don't act with nitric first because the amount of gold + Pt is greater than 25%.

 

[Yggdrasil]

Yes, that was not in line with this forum's objective, true.

We do not recommend melting metal powders that are going to be refined further, before a sale it can make sense as it easier to XRF a bar.
And diluting, icing and filtering the solution is just to get rid of as much AgCl as possible.
Then drop the Gold and evaporate for so processing the Pt.

After dropping the Gold you could go directly to Cementing the Pt without evaporating,
not sure how effective that is.
To know how much Copper to use add it in small quantity (Powder) and test often with Stannous.

When you getting close to barren, siphon off the liquid and set it aside as a stock pot with a solid Copper bar and air bubbling around the bar.
The Pt powder should be pretty pure at this moment.
If it aren't pure enough you could repeat it with a concentrated solution as there should be only Pt and Cu involved at this point.

Anyway I'm confused by your numbers as they do not correlate with the numbers in your first post?


1227g of alloy with proportions:
Cu:684
Au: 189.63
Pt:17.25
Ag:91.58

This gives an amount of 0.02gram of Pt

Now you are talking about
82.06 grams of alloy with 84.41 ppm Pt
Which is 0.007 grams of Pt

We are talking about amounts that are hard to see here.

 

[100tific]

Thank you Yggdrasil, your answer about the platinum and copper part was very helpful to me. As for the gold, I have always diluted the solution a lot before adding MBS. I never did it with the concentrated solution.
What I will do is eliminate the nitrous compounds with sulfamic acid and heat, and in that concentrated liquor I will add the MBS. I have never done it like this without diluting it, I hope it goes well.

Regarding the numbers, I said they are parts per thousand (1000). Not parts per million (ppm).
That is, in this last case, which I have 84.41 thousandths, it means 84.41 parts of Pt per 1000 of alloy. That is, 82.06g*84.41/1000=6.92g Pt. If I had 0.02g I would not invest any time or reagents in recovering it.

Thanks for your response.

 

[Lou]

This thread took a humorous turn but maybe @Abdoulapapatte and @100tific become the refining power couple! I certainly can think of worse places to meet a partner Both of you definitely have very good chemistry...knowledge!

Back to business though, as Miss 100tific is here to make money.

For cases such as yours, Miss 100tific, I always proceeded as follows:
1. granulate the material after assay confirming silver <5%w/w
2. Dissolve in aqua regia
3. Remove excess nitrates with sulfamic acid solution until ebullition of N2O stops. Sulfuric acid is produced in the reaction which will precipitate lead.
4. Dilute to approximately 2-3 M in HCl then filter any lead sulfate and silver chloride; rinsing filter cake with 0.1 M HCl until colorless. This filter cake goes to silver smelting where traces of gold and other PGMs are recovered.
5. To the mother liquor, I would remove the gold any which way (ferrous sulfate, as noted above is more selective than SO2 and its associated salts) until negative stannous test
6. Cementation of residual PGM with copper sheet as described above until negative stannous test for Pt/Pd, filtered and then then barren solution then goes for copper recovery with iron sheets. The air stirring recommended is not my preference because it can make allergenic mists and generate some chlorine if the HCl concentration is too high-- so I prefer a slow stir.
7. For the reduced PGM blacks recovered in 6., these I like to dissolve in HCl/H2O2. At this point, decisions must be made to get pure platinum and that depends on how much other anionic impurity is present (Pd/Rh/Ir/Ru). In some instances, a simple precipitation as the ammonium salt is enough to obtain 99.9% w/w Pt. In others, it is best to boil the solution to decompose Pd(IV), add a trace of reducing agent (i.e. sodium nitrite) and end up with Ir(III) remaining in solution and then precipitate the bulk of the Pt with ammonium chloride as the chloroplatinate. Everything at this stage depends on Pt to Pd:Ir:Ru:Rh ratios. For ratios when Pt to other PGMs is say >20:1, hydrolysis is usually indicated but as that gap narrows, some of the older classic methods are more appropriate to flip the ratio.

In general, Pt will easily be contaminated with Pd/Ir (especially if the solution is highly oxidized and/or cold) and less so with Ru/Rh (especially if the solution is filtered from precipitate warm, as these metallates are reasonably well soluble). Again, these coarse separations are made depending entirely on solution characteristics.

Edit: some emoji auto formatting needing fixed.