# platinum



## chasm1933 (Oct 5, 2007)

Can anyone help me? I dropped some platinum today and in the mud was a lot of green with the yellow which I understand is the platinum. All that was in the AR were the inards from oxygen sensors and that's why I can't figure out what happened. I mixed the AR per directions and heated it to a low boil for 2 hours. Then I dropped it with ammonium chloride. Any help will be appreciated. This is a great forum and has answered many questions for me already without even having to ask them. Thanks . Chas.


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## aflacglobal (Oct 5, 2007)

Have you done any acid washes ( Harold's method to remove any base metals ) to see what is left. You might start with the acid peroxide method to remove as much base metals ( inside of sensor ) as possible and then dissolve the remaining in AR. I guess you might be able to use Nitric to dissolve the base metals also. Don't quote me but the blue or green may be copper, I would think the sensor would have a copper winding of some sort :?: As Steve says, Trash in----Trash out. Start with as clean a material as possible, that way when you drop the Platinum other metals are not drug down with it. If they aren't there they can't interfere.


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## Platdigger (Oct 6, 2007)

There is no copper winding in these. Only platinum maybe palladium, and posibly some other metals deposited on a ceramic type material. At least the ones I have openned up. Were these just the ceramic tips that you were boiling?
Randy


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## aflacglobal (Oct 6, 2007)

I have never seen them but wouldn't it have some type of wiring of copper leading into it. Would the platinum be coated directly onto the ceramic or onto a base metal substrate.


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## Harold_V (Oct 6, 2007)

chasm1933 said:


> I mixed the AR per directions and heated it to a low boil for 2 hours. Then I dropped it with ammonium chloride.



While your Reader's Digest version of your procedure is interesting, if you followed it as you reported, you missed several steps that would be important for good results. 

Did you filter your material? Did you precipitate hot, or cold? Did you evaporate to expel excess nitric? (That you achieved a precipitation suggests the nitric was exhausted, but that may not always be the case). 

How much of the sensor did you process? Did you dissolve obvious metallic objects such as portions of the housing? The green crystals you describe may be nickel if so. Do you have any DMG (dimethylglyoxime)? If so, you can test the green crystals to determine if they are. Ask for guidance if needed. 

Please provide more information, detailing EXACTLY what you've done, and don't leave out small details. It's really hard to know what is happening when all information isn't provided. 

You are correct in assuming the yellow material is platinum. 

Harold


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## chasm1933 (Oct 6, 2007)

Thank you for replying to my question. After boiling on a moderate heat for 2 hours or so, I added the ac to the very warm solution. after an hour or so I aded urea. Should I have waited for the 25 hours to elapse before adding urea? Then I poured off the solution and rinsed it with water. When I saw what I had I stopped to find out what went wrong. I have more green then yellow in the pot. I worked with only the ceramic inards. Also 02 sensors have no copper windings. Hope I gave enough info. Chas.


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## chasm1933 (Oct 6, 2007)

By the way, yes Harold I did filter the material very warm before dropping the pt. Chas. and thanks again to all.


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## Harold_V (Oct 7, 2007)

I'm not familiar with the use of urea, so I hesitate to comment. My procedure ALWAYS included evaporation. 

I never referred to precipitation as "dropping". Dropping, to me, is seeing something end up on the floor. I have a strong dislike for that term when discussing precipitation. 

If I was still refining today, I wouldn't use urea (my personal choice, not giving advice). I see no reason to screw with a process that is known to work, and work well. I also see no good reason to add unnecessary constituents to a solution when my objective is to purify. Adding more contaminants seems somewhat counterproductive to me. 

I did all my filtering with cool solutions. That allows substances that are inclined to self precipitate as solutions cool to be eliminated by filtration, not combined with the values I seek to recover. 

Ammonium chloride should be added after filtration, with NOTHING else added afterwards. That insures that you don't get complex reactions that may precipitate unwanted substances, including them with your platinum. 

When the resulting cloud settles well, the solution should be decanted and tested for other values before discarding. It's not uncommon for some platinum to remain in solution. Unlike gold, it rarely precipitates totally. If your solution tests traces after precipitation, recover them in the stock pot. 

The yellow (or even orange) powder is very soluble in water-----so wash it with a dilute solution of ammonium chloride. Even then, test your wash water afterwards, for it is likely to contain traces of Pt. They can be recovered in the stock pot. 

Don't have a clue what to suggest about the green stuff. If I was to venture a guess, I'd suggest it's the result of a poor process. I'd suggest dissolving a little of it and testing with a drop of ammonium hydroxide, then a drop of DMG. If you get a pink reaction, it's nickel. It may also be iron, which can be tested as well, but you'll have to refer to Hoke for instructions. It's been way too many years since I last tested any. 

Harold


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## ChucknC (Oct 7, 2007)

I don't know this as fact, but all the people I know who work with PGM's say to never use urea with any possible PGM's in solution. It will lock the PGM in solution so you have to start over, or make the PGM's unrecoverable.

As for myself, I always use the evaporation of Nitric from an Aqua Regia solution rather than using urea. I've never had any luck using urea, so that's just my take.

As Harold said, the evaporation process is a tried ad true method. There's no need to reinvent the wheel or add an extra chemical. It could cause added steps(therefore more costs) or an unknown reaction. Stick with what is known and you won't go wrong.

Chuck


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## aflacglobal (Oct 7, 2007)

Harold you are a god. I swear to have no more knowledge than what you have learned over your years of self taught refining the procedures and techniques that you use, And to do so with such meticulous detail and precision.

Well you got my vote. You still amaze me Harold. Thanks

Can anybody else see this ? Just try not and confuse us small folks. :wink:


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## Lou (Nov 5, 2007)

It's that knowledge of his that got me over here! The man's seen it all.


Nice to see you here Chuck! Been awhile since I've talked to you.


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## Lino1406 (Nov 7, 2007)

Urea reacts with NO2, not with HNO3. If you use it
with no spare ammount it will convert to gases only, and
it actually cleans not adding dirth, you should add it before NH4Cl.
Lino1406


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## Joe (Nov 7, 2007)

Chasm, I happen to have the same problem right now. I thought I had put in some almost pure platinum for a second refining. 
I'm guessing that the green may not be a metal. I think it could be some sort of reaction involving the urea. 
I am thinking that I am going to incernate everything left in the pot after dehydration and then put it back through a refining process. 
Stay away from the urea. Boil down if you can. I've had the opportunity to try both. The urea makes a mess.


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## Harold_V (Nov 8, 2007)

Joe said:


> Boil down if you can.



I trust you're using the word "boil" in the loosest possible sense. 

When you evaporate, it should be conducted at a slow rate----if the solution boils-----*guaranteed*-----you'll be losing values. The cloud that comes off an evaporation process should be absolutely colorless, even when condensed on a cold surface. If you see the slightest trace of color, you're carrying off values. 

I colored the side of a new travel trailer purple that way by evaporating gold chloride too quickly. It's a very expensive way to learn a lesson. 

Harold


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## Joe (Nov 8, 2007)

Harold, thank you so much for the advice! What I understand you to be saying is that values will exit the vessel with vapors unless the value has been reduced to an elemental-metallic state. 
By the way, I don't think it is necessary to "kill" the nitric before precipitating platinum. I will go back and check.


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## Harold_V (Nov 9, 2007)

Joe said:


> Harold, thank you so much for the advice! What I understand you to be saying is that values will exit the vessel with vapors unless the value has been reduced to an elemental-metallic state.




That's correct. They also exit a vessel while being dissolved, due to the effervescence. It pays to keep a watch glass on your containers to return anything that may escape the solution. Do keep in mind, I did everything with added heat. If you work with cold solutions, they may not display the same characteristics, but then I can't imagine working with cold solutions. 



> By the way, I don't think it is necessary to "kill" the nitric before precipitating platinum. I will go back and check.



Please report what you find. It's been far too long for me to remember, not having refined since '95. 

One thing I'd comment on----and it's related to the PG metals not precipitating well from solutions. In order to get the best results when precipitating platinum and palladium, you are always well served to evaporate the solutions to a high level of concentration. You'll come to understand that weak solutions often won't precipitate at all, leaving you only recovery of values from any given batch with base metals. Sort of defeats your purpose. Learn evaporating, even if you don't need to eliminate nitric. 

Harold


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## Buzz (Nov 9, 2007)

Hi Folks,

Seems that switching from urea to evaporation is the way to go, for me anyway.

The thing i'm not clear on is, how do you tell when all the nitric has been evaporated or at least to a level where recovery is viable?

Regards
Buzz


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## lazersteve (Nov 9, 2007)

Buzz said:


> The thing i'm not clear on is, how do you tell when all the nitric has been evaporated or at least to a level where recovery is viable?



Buzz, 

When the solution gets syrupy add a little HCl to it, if nitric is still present you'll see more brown fumes with the additon of the HCl. Continue evaporating until the borwn fumes are no longer produced when more HCl acid is added. 

Steve


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## Buzz (Nov 9, 2007)

Thanks for that Steve,

Cleared that one up for me :idea: 

Regards
Buzz


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## Lino1406 (Nov 15, 2007)

If the green mud is somewhat grayish, and
if it comes after the yellow mud, it could
be also Ir ("the blue mud")
Lino1406


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## Lou (Dec 4, 2007)

Maybe we should make an interesting links thread and post a bunch of links to pertinent information.

For those of you who read German, or can figure out how to use a translator, this is a good demonstration of how dental gold is handled. Comes from a good chemistry forum.

http://www.versuchschemie.de/topic,8039,-Scheiden+von+Zahngold+im+gro%DFen+Ma%DFstab.html


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## lazersteve (Dec 4, 2007)

Lou,

Great link,

Google does a fair job at translating the page.

Translated German Site

King's Water aka Royal Water is AR in German (koingswasser) for those of you who didn't already know.

I've translated quite a few German Chemistry texts using another site for German chemical terms. I'll try to find the link.

Steve


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## lazersteve (Dec 5, 2007)

All,

Here's the remaining German Chemical term translations that google left out in the above link:

Abrauchen = defumed
Löseprozess = dissolution process
abgefiltert = filtered
Gaserzeuger = gas producer
Zutropfen = add dropwise
verwachsenes = growth
schwammförmigen = spongy
abgenutscht = drawn through a filter(suction/vacuum)
eingedampft = concentrated/solvent evaporated
zugetropft = /added dropwise
Schamotteschälchen = fireclaybowl/crucible
Boraxzusatz =addition of borax
vierwertigen = tetravalent
schwerlösliches = poorly soluble
ockerfarbenes = ocker-colored
chlorhaltiger = contains chlorine
nurnoch = still only
verd = dil(dilute)
fleischfarbener = flesh colored
kanariengelbes = canary yellow
aufweist = shows,exhibits
verglühen = anneal (steel; could be burnsomething off)
Hydrierkatalysatoren = hydrogenation catalysts
wegschütten = discard

These translations came from a girl named Jill that I located on ProZ.com last night.

Thanks Jill, you are awesome !!! :wink: 

If anyone is interested I could translate the site into English (with the owners permission of course) and post the translated version on my website.

Steve


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## Lou (Dec 5, 2007)

He is an acquaintance of mine, and goes by the name garage_chemist on http://sciencemadness.org/talk (a forum those of you who want to learn chemistry should check out!!).


There are several useful things on that Versuchschemie forum too, I suggest you all check it out (like all the synthetic experiments and preparations).


I'll be posting an English procedure for Pt, Pd, Ir, Os, and Rh by the end of the month. It will be on sciencemadness.org and will be more directed towards the chemistry behind it, but there will be a lot of photos.


Lou


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## lazersteve (Dec 5, 2007)

Lou,

I joined Versuchschemie earlier today and sent him a PM asking his permission to translate and post his Dental Gold experiment. I sent it in English and German, but he still hasn't replied.

I also invited him to the forum.

Does he do English ?

I been lurking around the science madness board for for many years now. It strikes me as a free for all at times. A few of those guys do some crazy stuff to get their chems. :lol: 

I'm not one to risk my life and limbs over a few hundred bucks worth of reagents. I'm a firm believer in safety first.

Hopefully Stefan will join our group.

Steve


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## Lou (Dec 5, 2007)

Yes, his English is excellent. I've asked him as well. He'll probably give us the go ahead.


Since you've lurked on SMDB for a while, Stefan's post might be familiar. Another version was also posted on sciencemadness, in English, but it was linked to his then recently posted versuchschemie work.

I have been at sciencemadness since a few months after it began (December 2002). What's your account name there? PM me.


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## lazersteve (Dec 5, 2007)

Lou,

I've remained completely silent on that board for my own reasons. I haven't joined, I've just observed. 

Steve


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## Lou (Dec 8, 2007)

Hello,

yes, I do give my permission to translate the procedure and post it at the forum you mentioned.
I am happy that there is so much interest in my refining process for gold, platinum and palladium.

Regards, Stefan



Quote:
Greetings Stefan,

I referenced your precious metals from dental alloy post at Versuchschemie forums to a forum called goldrefiningforum.com. The members there were quite impressed and asked if they could copy the post, translate it into English, and keep it as a reference on their site. May we have your permission to do so? It will not be used to make any profit nor will your words be altered. You will be duly credited.

Regards,
Louis

Your post was: http://www.versuchschemie.de/topic,8039,-Scheiden+von+Zahngold+im+gro%DFen+Ma%DFstab.html


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## lazersteve (Dec 8, 2007)

Lou,

Excellent!

Do you want to do the translation or shall I? 

Steve


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## Lou (Dec 8, 2007)

If you'd like I can do it but my German isn't the best and I get my modifiers all messed up when I try to make English out of it :/ Plus I'm kind of confused as to how to post it? Do I make a thread in tutorials, post it all, and then have Noxx lock it? Do I write it up in Word that's a copy of his and then attach it? I'm not the most tech-savvy person, but I can give it a go 

Not trying to cop out here, but I'm sure you'd handle it better 
8) 


Lou


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## Noxx (Dec 8, 2007)

Yes you post it then I lock it.
You can copy it or attach it, it isn't a problem.


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## lazersteve (Dec 8, 2007)

I wanted to translate it and post it in pdf format on my site and here, with the appropriate references of course.

I'll be more than happy to do the honors.

Steve


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## Lou (Dec 9, 2007)

I like your way better  Go for it Steve!!


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## lazersteve (Dec 9, 2007)

Lou,

I'm on page 15 of 16 now, it should be done within the hour. I worked late into the night on it last night.

I'll send you a proof to read before I post it.

Steve


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## lazersteve (Dec 9, 2007)

All,

The translation is completed. Lou and the original author (hopefully) will be reviewing my translation. After it get's their okay I'll post the pdf as previously discussed.

Steve


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