What is this?

[brjook]

I recently dissovled 110 G or 1/10 th 12kgf eyeglass frames in nitric.After the dissolution and wash I added the filtrate to AR.When there was no more bubbleing and the reaction seemed to have came to a finish there was a large amoutn of silver white flakes left over .What is this metal?.I recently looked at some post and said something about rhodium.If this is true how do i refine the said metal ?
Any help would be deeply apperciated.

 

[Geo]

its hard to make a guess without a picture to see (a picture is worth a thousand words) :lol: it could be several things. 1/10 GF means that of 100% of gold in the piece you have only 1/10 is pure gold.dissolving in nitric acid creates nitrate salts to form from base metals,did you put any of the white crystals in hot water to see if it dissolves? try a few in hcl as well. some salts dissolve in water and some dont,just experiment a little and post what you did and someone will be able to help you out im sure.

 

[brjook]

I put the metal flakes in water and hcl and nothing happens

 

[goldsilverpro]

Were the glasses super bright and shiny white metal to start with? If not, I can't see there being rhodium present.

 

[brjook]

A couple of pair was silver or white gold but still marked 1/10 12kgf .If it is rhodium what do i do to process it.it didn't dissolve in AR?

 

[samuel-a]

A couple of pair was silver or white gold but still marked 1/10 12kgf .If it is rhodium what do i do to process it.it didn't dissolve in AR?

Unless you are processing hundreds of thousands pieces a month, don't bother your self with it, just collect it and put aside to accumulate. To start experimenting with Rh, you will need at least couple grams of those foils...

1/10 GF means that of 100% of gold in the piece you have only 1/10 is pure gold.

No offence, but that is not correct.
"1/10 12K GF" means that 10% of the GF piece mass is 12K gold.

 

[Geo]

absolutely. i was in the middle of something else and lost my train of thought. too if its 1/10 or 1/20 10k or 12k its usually only plated on one side unless marked double sided.sorry about that.

 

[goldsilverpro]

A couple of pair was silver or white gold but still marked 1/10 12kgf .If it is rhodium what do i do to process it.it didn't dissolve in AR?

The only place I can think of that you would have rhodium is if it were plated on the surface. It is hard and white and usually bright and shiny - almost looks like chrome. It is often applied to jewelry to prevent tarnish or to change the color from yellow to white. For this application, it is always plated very thinly, about 5 millionths of an inch. At that thickness, it is only worth about 6 cents per square inch of plated area. I doubt if the plated area on eyeglass frames would greatly exceed 1-2 square inches. If the frames are yellow to start with, I can't see how there would be any rhodium present. So, to me, the only candidates you had were the 2 white ones. If they are really rhodium plated, you'll be lucky to have a quarter's worth, total. Forget the rhodium and worry about the gold you have.

 

[goldsilverpro]

absolutely. i was in the middle of something else and lost my train of thought. too if its 1/10 or 1/20 10k or 12k its usually only plated on one side unless marked double sided.sorry about that.

The gold filled alloy is never applied by plating. In fact, since it contains 3 or 4 different metals, it would be almost impossible to plate it in the necessary percentages with any sort of consistency. It is a sheet of karat gold alloy laminated to base metal, usually a copper alloy. After lamination, the sandwich is usually rolled to some desired thickness and the parts are made from that.

 

[Geo]

ahh. thank you for the clarification. im better at electronics. :lol:

 

[brjook]

Thanks for the info.It was a very small amount of material 1/10 gram at most was just curiuse what it was and why it didn't dissolve in AR

 

[brjook]

Still running into the very silvery flakes.My AR done a great job on ther gold but again have the same flakes as before .As stated before someone suggested saving them til i have a accumlation of the flakes.So i do this what then.They do not dissolve in nitric or AR.How do you process them if they are Rhodium.Most of my stock is from old GF watch bands and old GF jewlery.

 

[Geo]

PT dissolves in boiling AR. have you tried that?

 

[brjook]

Yes i boiled it in a 500ml beaker with another 500 ml beaker on top with cool water that condensed the Auric Chloride during the boiling

 

[butcher]

maybe I am wrong, but why would someone make eyeglasses with cheap gold fill (very little gold) and then add the platinum group metals? I would think chrome, silver or some other cheaper metals would be used.

 

[brjook]

So ya saying chrome does not dissolve in Ar or nitric ?
'

 

[butcher]

No I am not saying that,

But there are metals that may be resistant to the acid you are using, just because they do not dissolve easily does not make them all that valueable, or platinum group, (titanium, tungsten coating?) I do not know just trying to get you to see with a wider veiw.

here is where do not throw away until you have tested come's to my mind.

 

[brjook]

it keeps showing up .This is the best photo i could get to show how shiny this material is .As stated it might not be a PM but any idea what it is would settle my curiousity.

 

[butcher]

brjook,
I do not know the answer to your question.
Here what I think, that seems like a lot of metal powder for what little you have processed to be a metal with a high value (110 grams of cheap gold fill glass frames), glass frames can be made from many, different metals. Some alloys fairly exotic, to make small wire frame flexible, strong, resistant to constant corrosive environments (worn of sweaty face, handled with corrosive solutions on hands and so on), I wont go on you get the idea, the gold fill, or plating may not only be for looks, but also to keep metals in the glasses from leaving green marks on your face from wearing a corroded pair of glasses.

Other metals like tungsten, titanium are possibly used.
To me as I have said I doubt you would find much Pgm, although maybe palladium but I do not know for sure,

I would look up the information of what metals glass frames are made from, look up the acid resistant metals (like titanium, tungsten) and find tests for these, you already know some of the acids (and conditions) this metal did not dissolve in, you may be able to narrow down the possibility’s of this mystery metal, There are tests for most any metal (but sometimes the test, or chemical, or procedure may not be worth time or expense to follow through with to find out)

If your still bent on believing you have some very rare precious metal there are very simple tests to find out, putting these metals into solution is usually the first step (well if these powders did not dissolve in boiling hot aqua regia, that has already eliminated several PGM's, did not dissolve in nitric eliminates silver or palladium, very doubtful it is Rh, Ir. Os on cheap glass frames (but you could go to the trouble of proving me wrong).

I say it would be a waste of time to pursue further, unless curiosity just will not let you quit, but remember curiosity killed the cat but also can be a great learning tool.

Here is something I would try, add 30% hydrogen peroxide to these metal flakes and then 32% HCl and heat, when peroxide quits reacting vapor off water (formed in reaction) to concentrate, if metals not dissolved when acid concentrates add more 30% H2O2, and see if these metal powders will dissolve.

 

[goldenchild]

brjook,

I would put money on those flakes being Rhodium. Processing many many watchband tops I can tell you for sure that gold filled jewelry is sometimes plated in Rh.

Edit
And I forgot to mention Rh is processed with H2SO4