# Values from filter paper



## markqf1 (Jun 30, 2008)

I have several different colored powders of pgm's stuck in the filters.
Some of them are regular coffee filters and some are filter paper.
Does anybody know the best way to get them out?
I have a furnace and thought about burning them away.
Anybody that has faced similar problems ,... your input would be greatly appreiciated!

The different powders test positive fo pt, pd, and maybe rh. :?: 

Thanks for many help in advance.

Mark


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## lazersteve (Jun 30, 2008)

Mark,

The PGM ammonium chloride salts are all water soluble. 

Hot water should get them clean very easily.

Steve


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## markqf1 (Jul 1, 2008)

Thanks Steve,
How would I then recollect them from the distilled water,...evaporation?

Mark


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## lazersteve (Jul 1, 2008)

Mark,

Any normal PGM reducing agent at the proper pH levels:

*Examples :* hydrazine sulfate (Pt, Pd, Rh basic pH solutions), zinc dust (Pt, Pd, Rh (slightly acid pH solution), etc.

You could also evaporate and calcine/incinerate to yield the metal from the complex.

Steve


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## markqf1 (Jul 1, 2008)

In your opinion, which way is more cost effective?
I guess your saying to add a little hcl or h2so4 if I want to precipitate it with zinc.. :?: 

Mark


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## lazersteve (Jul 2, 2008)

Mark,

The most economical way would be evaporation followed by slowly incineration/calcining. 

You'll end up with a black powder residue (your PGM) after calcining.

Steve


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## Lou (Jul 2, 2008)

Ammonium hexahaloplatinate, rhodate, palladate etc. are all salts, *not * complexes, just quite soluble salts, like almost every ammonium salt. A complex would be something like... (NH3)2Pt(NO2)2 where platinum is +2 oxidation state and their are two ammines which coordinate with it or conversely, PtCl4(2-) (that complex results when HCl is added to PtCl2). Ligands do not affect oxidation state of the metal to which they coordinate. They may be easier or harder to reduce than salts, but they are not the same thing electronically and structurally. Technically Steve, you are right that when the ammonium salts dissolve, they complex (with water in fact!) but that's not really the type of complex chemists mean in coordination chemistry.


Mark, if you simply want to produce a mixed bag of Rh, Pt, and Pd then you do not want to bother making the ammonium hexachloroPGM salt, instead you want to remove the nitric and then cement with zinc. No ammonium chloride is needed. If you want a level of separation, then you do the ammonium chloride method.

Just to clarify Steve's words...
You do NOT want to heat the H2PtCl6 or H2PdCl6 solution to the point where it is decomposing! Your platinum will 'evaporate' away. You can only do the incineration/calcining in limited circumstances, in fact, it is limited only to the +4 oxidation state ammonium salts. This is because the ammonium cation can couple with some of that extra chloride and leave as ammonium chloride gas. NEVER ever heat a PGM salt that doesn't have ammonium in it.

Lou


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## markqf1 (Jul 2, 2008)

Lou,
I'll probably be looking more to the zinc cementation method as I move forward.
For this batch though, I have alot of messy coffee filters as well as regular filter paper with the ammonium salts (positive stannous tests) stuck to it.
Just looking for the best way to get it out , seperate it , and reclaim it from the paper, which in the case of the coffee filters, is very deteriorated.

Mark


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## Rag and Bone (Jul 7, 2008)

I'm getting ready to incinerate my accumulated filters that contain values. For practice, I burnt some unused coffee filters with a propane torch in a stainless skillet. Pieces of burnt filter blew out of the pan.

How do I prevent losing values?

Also, many of the filters are stained with yellow auric chloride and purple colloidial gold. What form will these values take after incineration?


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## lazersteve (Jul 8, 2008)

Rags,

I use a SS splatter screen to cover my skillet while heating from the bottom.

The residue after incineration will appear as a mix of fine powders which can vary in color from green to black (even purple) and white ash.

Sieve the residue, run a magnet through it, and process it. 

I start off with hot muriatic to get the oxidized base metals out then go to HCl-Cl or AR.

Beware of breathing the copious amounts of smoke when burning. I use a long PVC pipe fitted over the handle of the skillet to give me some distance from the heated pan when doing bench sweeps due to the smoke. I made a complete video of this one for a jeweler forum member, but never got around to posting it on my site.

Steve


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## markqf1 (Jul 8, 2008)

I am reluctant to incinerate the filters without trying to clean them out first.
I believe I read, that the paper can cause carbon to affect the pt especially.
I think Hoke says the pt papers can be washed with a solution of ammonium chloride and water, with minimal loss of powder.
I think I'll try this first.

Anybody know if the same method would work for the filters with pd?

Also, Steve,
If I took the black powder thats supposed to contain rh, and mixed with a little hcl and water, then heated it, what color would I be looking for in the test tube?

Mark


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## lazersteve (Jul 8, 2008)

Mark,

the stannous chloirde Rhodium test requires the Rhodium to be in solution (Bisulfate fusion product or other means to make soluble).

The black powder is already reduce to metal and won't test with stannous.

The desired color is Rose Red.

Steve


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## markqf1 (Jul 8, 2008)

Thanks Steve,
This is a bisulfate fused powder that I precipitated with zinc and, not the reduced metal.
I'll let you know if it works.

Mark


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## Platdigger (Jul 8, 2008)

If you used zinc.....wouldn't that be a reduced metal?
Randy


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## lazersteve (Jul 8, 2008)

Randy is correct, once you add the zinc, the stannous test is null and void. 

Test your solution before you add the zinc next time.

Rh metal has a very high melting point that should identify it from the others.

Steve


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## Harold_V (Jul 8, 2008)

markqf1 said:


> Lou,
> I'll probably be looking more to the zinc cementation method as I move forward.
> For this batch though, I have alot of messy coffee filters as well as regular filter paper with the ammonium salts (positive stannous tests) stuck to it.
> Just looking for the best way to get it out , seperate it , and reclaim it from the paper, which in the case of the coffee filters, is very deteriorated.
> ...



Simple. Rinse them well in water, until everything is in solution (it happens almost instantaneously), then recover values from the solution with zinc. You can also pour the solution in your stock pot. Incinerate the filters for final processing. Your losses will be virtually 0.

Harold


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## markqf1 (Jul 9, 2008)

Thanks Harold,
That's exactly what I'll do.

Mark


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