# Cementing Platinum onto copper



## kadriver (Oct 6, 2011)

Here are some photos of a quantity of filtered liquid waste from a recent karat scrap gold refining. 

The karat scrap gold did include some pieces of dental gold.

Once the gold was dropped with Sodium Metabisulfite, the liquid was filtered to remove all traces of the gold.

Some of the fine gold powder made it through the filter paper on the first pass. 

I had to pour the liquid throught the same filter twice to get all the gold that was suspended in the liquid.

The second time through the filter paper, all traces of the suspended gold were captured in the filter paper.

I put the gold ladden filter paper into a melting dish, covered it with borax and slowly burned the paper away and recovered a nice gold bead that weighed .3 grams

Once all the gold was removed from the liquid waste, I placed a clean copper wire into the filtered liquid.

After about a day, this film of black material formed on the copper wire (see photo).

Is this platinum that has cemented onto the copper wire?

I have done this in the past. Each time I was able to shake the black material off the wire, then filter the liquid to get the black material.

I just saved the filter papers with the black material in them. I allowed them to dry then folded up and placed into a labeled plastic bag.

I have saved all my gold wastes in two 5 gallon buckets.

I am going to try and cement with copper to get any metals from this waste.

I must read up on platinum refining in Hoke's book.

Any guidance would be appreciated.

thank you - kadriver


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## kurt (Oct 6, 2011)

Looks like something in the PGMs family to me. Desolve a little bit in a bit of AR & test it.

Kurt


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## goldenchild (Oct 6, 2011)

Could very well be gold. My advice to you is in my signature line. I would definately take a second look at your wastes!


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## notch (Oct 6, 2011)

The Gold will cement first then the PGMs. Add a small amount of Bisulfite or Sulfite and cover to keep the air out. This will maintain a reducing environment. When the solution turns a Light Blue, it should only contain Copper and Base Metals.


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## kadriver (Oct 6, 2011)

I did test the liquid after the gold was dropped with SMB.

I always place a tiny drop of AuCl on a paper before I drop the gold to use as a reference for the stannous test.

Once the gold was dropped, I tested with Stannous Chloride and the test was negative for gold.

Thank you for your input.

kadriver


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## freechemist (Oct 11, 2011)

What I do not understand is: Why did you not test your filtered solution, after precipitation of gold, with stannous chloride for Pt and/or Pd too, before trying to cement them onto copper? Testing with stannous chloride gives reliable results for Pt and Pd, too, not only for gold.

Regards, freechemist


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## Harold_V (Oct 12, 2011)

kadriver said:


> Some of the fine gold powder made it through the filter paper on the first pass.


I question your need to filter. If you'll allow gravity to work for you, you can eliminate that operation, which is useless in the scheme of things. 



> I had to pour the liquid through the same filter twice to get all the gold that was suspended in the liquid.
> 
> The second time through the filter paper, all traces of the suspended gold were captured in the filter paper.


Much more desirable to have them with the balance of the run. Trapping them in a filter makes no sense. 



> Is this platinum that has cemented onto the copper wire?


Most likely a mixture of palladium and platinum, although it's possible it can be either of them alone. You can usually tell if you have palladium present, thanks to the dark color of the residual solution. If it contains only platinum, it should have a more orange to light yellow coloration, but with much palladium it should shift towards dark orange, even brown. Stannous chloride and DMG are your friend. 

Harold


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