# Platinum Refining Practice with a Pure Pt Coin



## kadriver (Nov 7, 2017)

I've got a Pt coin and I want to do a practice refining, and I want to shoot a video of it.

This'll be my first time doing Pt.

I've already rolled it thin 0.24mm and cut into strips and twisted as per Hoke.

I'll start be incinerating to burn off any oils.

I plan to dissolve in hot AR, then denoxx via evaporation and hydration with HCl.

Then precipitate the Pt salt with ammonium chloride and calcine.

Any insight would be greatly appreciated.

Should I set up a reflux condenser, or just cover with a watch glass?

I'll be doing a 1/4 oz coin. Is there a certain concentration or pH I should attain before precipitating?

Is ammonium chloride the right precipitant, or should I go with something else?

Thank you!

kadriver


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## FrugalRefiner (Nov 7, 2017)

kadriver said:


> Is ammonium chloride the right precipitant, or should I go with something else?


Lou recommends potassium chloride.

Dave


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## goldandsilver123 (Nov 7, 2017)

Be sure to anneal it, it will dissolve faster.

If you plan to calcine it, I think ammonium chloride is a better precipitant, as everything will turn to gas, with potassium chloride there will be liquid potassium chloride. 

Potassium chloride will be better if you plan an aqueous reduction, like with ammonium formate.

*(NH4)2PtCl6 -> Pt (s) + 2NH4Cl (g) + 2 Cl2 (g)* Edit: see Lino1406 post below

K2PtCl6 (s) -> Pt (s) + 2KCl (l) + 2Cl2 (g)


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## Lino1406 (Nov 7, 2017)

Sorry. Breaking Cl2 from a molecule is not that easy. 3(NH4)2PtCl6 = 3Pt + 2NH4Cl + 16HCl + 2N2


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## cuchugold (Nov 8, 2017)

I can guide you, if you'd like to do it my way, adapted from previous pioneers. Not very sexy, but... simpler, in my opinion.
1-Lead fusion, to separate the hardener, which is likely Ir (or Ru).
2-Diluted nitric acid treatment to get rid of the lead. 2-a- You have no Rh there, but if you did, you can get most of it here, with a Potassium bisulphate fusion. If you so choose, otherwise it'll drop in point 4 along with everything else.
3-Weak A.R. treatment to dissolve the Pt, leaving the Ir in beautiful almost pure crystals.
4-Controlled bromate hydrolysis, to drop whatever remaining impurities.
5-Sodium formate reduction of 9999 Platinum.

Ammonium Chloride never used. Potassium Chloride used if you wish to pursue higher and higher purities, which few can measure anyway.
All documents regarding this method are in the library.

Coins are nearly all Pt-Ir, so this method fits well. In any case, I"ll enjoy whatever journey route you choose. 8)

Edit to add: To all those life saviors that are going to point out to me, that lead is poisonous, and that Bisulphate fusions are dangerous, and that nitric acid is not a good beverage, please save your breath. We are all adults here, I hope. Peace. :G


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## nickvc (Nov 8, 2017)

I know you have a specific reason to do this but just as a thought, your customer gives you bench sweeps which contain Pt, well most modern alloys contain magnetic metal,cobalt if I remember correctly, so some separation prior to refining can be done with a magnet inside a sturdy plastic bag,the collected powder can then be treated as per Hoke with cold weak AR to remove any gold, then if you nitric the remaining powders you should be able to recover any Pd and Ag and if there is enough silver the remaining Pt which can be cemented after forming silver chloride with Hcl. 
I know you are a clever and sensible refiner but I’d recommend staying away from PGM refining and simply collect the powders together and send them to Lou who can safely refine them and re supply product if that is your aim in producing platinum of 999 purity and then to re alloy. If you intend to sell the PGMs then simply collect and melt when you have decent volume or again return to your customer for his retirement fund.


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## goldandsilver123 (Nov 8, 2017)

Lino1406 said:


> Sorry. Breaking Cl2 from a molecule is not that easy. 3(NH4)2PtCl6 = 3Pt + 2NH4Cl + 16HCl + 2N2



I wrote that equation whitout any consulting, it makes sense to have the nitrogen as a reductant (from -3 to 0) than chlorine (from -1 to 0). I never saw any tint of green when calcining this complex as well.

What about the K2PtCl6 equation? As one method of making this type of salt is grinding KCl or NaCl (Na2PtCl6) with powdered platinum in a chlorine abudant atmosphere at 600 ºC. It will reduce it or it will make other platinum chloride salts?


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## Lou (Nov 8, 2017)

There will be some chlorine formation even with chloroplatinate.

With palladate, the loss of chlorine can happen simply by boiling K2PdCl6 in hot water whereupon you get K2PdCl4.


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## cuchugold (Nov 9, 2017)

nickvc said:


> I know you are a clever and sensible refiner but I’d recommend staying away from PGM refining and simply collect the powders together and send them to Lou who can safely refine them and re supply product if that is your aim in producing platinum of 999 purity and then to re alloy. If you intend to sell the PGMs then simply collect and melt when you have decent volume or again return to your customer for his retirement fund.


I agree with all of this. Unless well equipped and trained, Pt refining is cumbersome from dissolving the initial material to melting the pure sponge or blacks. The other PGM metals are even harder, and more tedious. It's not like gold at all.

In small quantities it is an intellectual pursuit, and economically the juice is not worth the squeeze, at all.


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## g_axelsson (Nov 9, 2017)

Hey, don't listen to those negative voices. I'm looking forward to see your video.  

This is the right way to learn refining, start with known material to learn what to expect, then go on with mixed materials to find out how hard it is to separate two PGM:s from each other.

Some people goes on to become refiners of PGM:s too, but you have to start somewhere. It is hard to put a price on knowledge and I applaud all your crazy experiments, if not for anything else, just to show that it can be done even if it works slowly. For example the placer with bleach.
Sharing these videos is a good counterweight to all the back yard newbies trying to refine gold and other stuff.
You are not the only one learning from your experiments.

I have some links to platinum refining on the wiki, you could check the references if there is something you haven't seen there.
http://goldrefiningwiki.com/mediawiki/index.php/Platinum

Göran


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## cuchugold (Nov 9, 2017)

g_axelsson said:


> Hey, don't listen to those negative voices. I'm looking forward to see your video.
> 
> This is the right way to learn refining, start with known material to learn what to expect, then go on with mixed materials to find out how hard it is to separate two PGM:s from each other.
> 
> ...


Thanks for that link!. It is way too easy to spend a lifetime in this topic. Addictive for me. :?


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## nickvc (Nov 9, 2017)

Göran I know KA knows his way round but for me the risks outweigh the potential financial gain, PGMs are one nasty set of metals to have in salt form of any kind without all the necessary safety equipment and very good extraction and scrubbing, my advice is to anyone who reads this thread it’s not worth the risk if you have other choices or materials to work with, you need to be very clean,accurate and an advanced refiner to mess with PGMs by choice.


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## g_axelsson (Nov 9, 2017)

Yeah, PGM refining is not where one should start a refining career. There are quite definite dangers and complications you have to deal with.

From an economical standpoint, PGM is for most people something that is best sold unrefined.

Göran


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## kadriver (Nov 10, 2017)

I looked at the process Calm Morrison describes in her book in the section titled "Getting Aquainted With Platinum"

Its simple and straight forward:

Incinerate (or anneal)

Dissolve in hot AR

Classic denoxx

Filter

Precipitate with ammonium chloride

gather the salt in a filter (she says dry it, but i'm not going to do that)

Burn the salt in a fused quartz dish

Melt into a button

The reason I'm doing this is to gain experience for some other PGM experiments that I'd like to do and make videos:

Recover and refine metals from catalytic converters

Refine my stock pot

Thank you!


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## cuchugold (Nov 10, 2017)

A good plan executed today is better than a perfect plan executed next year!. Many or most refiners keep the final product as sponge, only to be melted when a customer requests a certain alloy as final product. But don't let that keep you from anything you wish to do!. Good luck. I enjoy the videos!.


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## ARMCO (Nov 10, 2017)

g_axelsson said:


> Hey, don't listen to those negative voices. I'm looking forward to see your video.
> 
> This is the right way to learn refining, start with known material to learn what to expect, then go on with mixed materials to find out how hard it is to separate two PGM:s from each other.
> 
> ...



A hearty "Amen" to the above.
I love your videos. I'm looking forward to this one.

The title says it all and I think a couple of people didn't read it closely..... "Platinum Refining _*Practice*_...."

...."a good counterweight to all the backyard newbies" 

One of the things that I pick up from your videos is your patient and methodical practice. Keep it up, you set a good example in the middle of where bad examples are aplenty!

Thanks again


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## kadriver (Nov 12, 2017)

I got the Pt dissolved today (video uploading as I write this). Tomorrow I'll precipitate with ammonium chloride and calcine to sponge. I've never melted Pt. The jeweler does platinum rings regularly with a tiny jeweler's torch.

I've got a thick melt dish, brand new. Been saving it for years for this day to arrive. I'm going to try and melt the sponge with oxy/acetylene. Should do the trick, it's the hottest flame on the planet.

Any tips would be greatly appreciated!

kadriver


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## kadriver (Nov 12, 2017)

The jeweler's torch is oxy/propane.


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## kadriver (Nov 13, 2017)

Here is Part One video link:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=26311


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## cuchugold (Nov 13, 2017)

kadriver said:


> I got the Pt dissolved today (video uploading as I write this). Tomorrow I'll precipitate with ammonium chloride and calcine to sponge. I've never melted Pt. The jeweler does platinum rings regularly with a tiny jeweler's torch.
> 
> I've got a thick melt dish, brand new. Been saving it for years for this day to arrive. I'm going to try and melt the sponge with oxy/acetylene. Should do the trick, it's the hottest flame on the planet.
> 
> ...



If the dish is quartz it will melt too, of soften into a glass mess. For smaller losses in melting make a compressed pellet with your sponge with a steel dice and hydraulic jack. For minimal losses, and such small melt quantities, make a pellet, fit it inside a sintered zirconia crucible, cover it, and put it inside a graphite crucible. You can melt it with a very small electric arc furnace. There are plans on the internet to make such furnaces cheap. They are dangerous devices though. As I said before, conduct all your experiments, till you are satisfied, and leave the actual melting of the sponge or blacks for last.

Now you know how slow dissolving the initial material is. If you had a Platinum ring made with some 10% Iridium in it, you'd still be "dissolving it", for a few more weeks.

I hope it helps.

Edit: If you do not have or not want to use an electric melter, the recommended torch fuel is oxy-hydrogen, with acetylene the worst choice, and oxy-propane somewhere in between. I'm sure all three will produce enough temperature for a melt, with losses and contamination.


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## kadriver (Nov 15, 2017)

here is the link to part2

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=26319

kadriver


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## cuchugold (Nov 16, 2017)

I admire your patience and dedication.

Another way to do it, that produces acceptable results with fewer losses, is to cement the pure Platinum from the syrupy H2PtCl6 solution with very pure magnesium or zinc. It bypasses the intermediate ammonium salt processing completely. Very suitable to the small refiner.

Another: One professional refiner, keeps boiling the purified (after hydrolysis without bromate!) H2PtCl6 till it is a red solid, then heats it up in a tube furnace to 350 C and converts it to brown PtCl2, with HCl and Cl2 evolved as gases (and due scrubbing). Then reduces the PtCl2 to Pt using a stream of hydrogen. This is probably the route to the purest metal, but it requires more equipment and proper technique.

Others keep using the ammonium chloride route... because they can!.

Welcome to the ~<0.1% club of chemists that have processed Platinum!.


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## kadriver (Nov 18, 2017)

cuchugold said:


> Another way to do it, that produces acceptable results with fewer losses, is to cement the pure Platinum from the syrupy H2PtCl6 solution with very pure magnesium or zinc. It bypasses the intermediate ammonium salt processing completely. Very suitable to the small refiner.



This sounds very useful, I'll have to give it a try.

I don't want to become a professional Pt refiner, just want to be able to process the small pieces of Pt that I have, and do my stock pot so I can shoot a video.

Thank you for those useful tips.

kadriver


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## cuchugold (Nov 18, 2017)

kadriver said:


> cuchugold said:
> 
> 
> > Another way to do it, that produces acceptable results with fewer losses, is to cement the pure Platinum from the syrupy H2PtCl6 solution with very pure magnesium or zinc. It bypasses the intermediate ammonium salt processing completely. Very suitable to the small refiner.
> ...


This will hurt many, but here it goes anyway. I hope you can swallow it, because I'm on the move to hopefully bigger and better things. These are only comments on HOW you may improve your technique, if you learn WHAT to do. Only after suffering the initial garbage refining advice, you are ready. I think you've suffered enough.

1-To dissolve, QUICKLY, the Pt alloys (of which you will only encounter 3 or 4, not 5, because the commercial alloys are generally binary, and Osmium does not exist for you or me). But never mind, because it applies to ore too. You must find a metal to alloy it with. Similar to what you do with inquarting gold. Hoke speaks of lead, zinc, silver. There are more, like gold karat (spoken by 4metals), by deduction pure gold, and also aluminum, and a few others. Pick your poison: To dissolve QUICK, instead of the 7-8 hours (or never), you must alloy with something. Ir and Ru (common hardeners) in jewellery cannot alloy with lead. Therefore, they separate from lead, in manner similar to solvent extraction but at 1,100 C. This is my chosen path, usually. In a passing manner, as if casual, this is described by Hoke, when she speaks about the Acton refinery, and also somewhere else in the same book. Lead fusion paper by Gilchrist posted in the books section by Jimdoc, I believe.
2-Now you are with an alloy. Depending on your alloy, the process follows. Your main task is to get rid of the other metals and get the Platinum in a relatively pure solution. Usually nitric acid is used, except for Aluminum and karat gold. (4metals has posted clearly his process. If you follow the recipe you get your turkey cooked).
3-Once you get the platinum powder dissolved with weak aqua regia, or preferably a non-nitric acid process, such as chlorate + HCl, or HCL + H2O2, or HCL + Cl2, then you go to bromate hydrolysis (or bromate-less hydrolysis). Use 4metals method, or Lou's without Bromate. If there were 100 Platinum refiners in the world there would be 500 methods of "Hydrolysis". Pick one. It doesn't matter, really. You will soon do it YOUR WAY.
4-After you filter out all the hydroxides (maybe 2 filtrations are needed, for a fast and a slow , 1-2 punch hydrolysis, which I favor), then you cement with magnesium. Why not zinc?. Because impurities in magnesium are usually calcium and sodium, which AID your cementing, and not heavier metals like lead in zinc, which TWART your aims of pure metal.
5-After you get your cemented platinum, you can compress into a pellet, re-refine it, etc, etc. No need to go to intermediate salts. You pack it into a pellet or pellets, and leave it like that, waiting for your customer needs. After that, you can forge it hot, like Wollaston did, for the purest product. Seek the paper. After it is in a continuous metal button you may melt it. If you have a big quantity, and access to an induction vacuum furnace you can melt it there.

The rest of the Platinum group metals are interesting, but not from any financial perspective, except if you can get a LOT of them continuosly.

That's off the top of my mind, if you think you know better, then you are probably right, as "it depends". I hope to bring discussion and comments into the matter, but I know I will likely get none. Maybe a few insults. In any case God bless the Platinum Gods, and William Hyde Wollaston, my hero.


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## Lou (Nov 18, 2017)

I already told Kevin over the phone that adding some salt to the evaporated syrup will prevent overdrying to PtCl2.

This is practice for refinery sponge as he said. What we call 995 Pt that goes for hydrolysis to 4N. Then it can be melted in lime or Y2O3(7%)ZrO2 crucibles. Lime cleans up any W/Mo/Ta/Nb/Ti/Sn etc.

I melt Pt in quantity with induction but the best cleaning method for certain impurities is an oxidizing flame in a lime furnace. One can see how clean of basemetala the Pt is by how it looks. Also, any oxidizing flame can be used. Sooty flames can carbide the Pt and any reducing flame can cause interactions with certain crucible materials.


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## cuchugold (Nov 22, 2017)

Thanks Lou!. After cleaning those non-PGMs, what would the typical assay show as impurities?. Maybe hydrolisis can be skipped completely for most applications. :idea:


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