Platinum Refining Practice with a Pure Pt Coin

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kadriver

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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
 
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)
 
Sorry. Breaking Cl2 from a molecule is not that easy. 3(NH4)2PtCl6 = 3Pt + 2NH4Cl + 16HCl + 2N2
 
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
 
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.
 
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?
 
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.
 
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.
 
Hey, don't listen to those negative voices. I'm looking forward to see your video. :D

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

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
Thanks for that link!. It is way too easy to spend a lifetime in this topic. Addictive for me. :?
 
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.
 
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
 
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!
 
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!.
 
g_axelsson said:
Hey, don't listen to those negative voices. I'm looking forward to see your video. :D

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

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
 
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
 
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.

Any tips would be greatly appreciated!

kadriver

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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