# Potassium Chlorate & Pd



## NoIdea (Jul 23, 2011)

Evening All, just a quick Q on 4Metals thread/method "Separation and Purification Au,Pt,Pd,Ag,Rh,Os,Ir,Ru" and the dropping of Pd using sodium chlorate and an alternative. My Q is: will potassium chlorate work and will it co-precipitate anything else, assuming the base metals are absent.

Got some and would like another use for it, other that pyrotechnics :lol:

Thanks

Deano


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## Lou (Jul 23, 2011)

It doesn't work as well at all.

KClO3 will form the in situ chlorine gas needed. It also forms K2PtCl6, an orange-red powder.

You may be better off just adding peroxide.


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## NoIdea (Jul 23, 2011)

Thanks Lou, in 4Metals discription Pt is dropped before Pd. So in this case it would be OK?

Cheers

Deano


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## Lou (Jul 24, 2011)

Sure, but as a general rule I avoid KClO3. K2PtCl6 is much more soluble than ammonium hexachloroplatinate anyway.


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## NoIdea (Jul 24, 2011)

Thanks Lou, ill keep that in mind.


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## HAuCl4 (Jul 25, 2011)

Lou said:


> K2PtCl6 is much more soluble than ammonium hexachloroplatinate anyway.



Lou: What Pt salt would be best suited to purification by crystallization, re-dilution, re-crystallization, etc. (Something similar to silver nitrate).? :?:


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## Lou (Jul 25, 2011)

Probably that one (K2PtCl6) in specific as it forms cubic crystals that may be driven from solution with ethanol or isopropanol. 


FYI silver nitrate need not be purified by recyrstallization: often, it is sufficient to merely melt and hold at 460*C until the other base metal nitrates have decomposed completely, and then redissolve in hot water and filter out the oxides of copper, nickel, and lead. In this case, one would pour the AgNO3 onto a stainless or quartz plate (stainless is preferred) and break it up by flexing the plate or light taps with a glass policeman. 


Lou


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## HAuCl4 (Jul 26, 2011)

Neat. Thanks!. 8)


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## freechemist (Jul 26, 2011)

Lou wrote:
_K2PtCl6 is much more soluble than ammonium hexachloroplatinate anyway._
If I remember well, Harold in one of his posts, mentioned the coprecipitation of Pd and Pt as hexachlorometallates(IV), before Au-precipitation in the refining process of PGM-rich dental scrap. This can well be done by KCl, even if the potassium salts are more soluble than the ammonium salts. This doesn't matter, as long, as you wash the precipitated salts with an about 1 molar KCl-solution before further treatment, because the thus added small quantity of process-inert KCl does not disturb the separation of Pt and Pd.

To HAuCl4's question about recrystallization of hexachloroplatinate(IV): 
This can well be accomplished by chemically reacting it to a different, easily soluble platinum-compound, which, as an aqueous solution can be purified by filtration and reprecipitated in a pure form by appropriate chemical reaction(s). In such a process it is preferrable, to use K2PtCl6 in place of (NH4)2PtCl6.


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## Lou (Jul 26, 2011)

Well one can reduce it to K2PtCl4 and make all manner of soluble complex salts (namely ammine nitrites).

If I recall rightly, hot solutions to which alcohol are added will even reduce Pt(IV)--> Pt(II).


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## HAuCl4 (Jul 29, 2011)

Can it be said that PtCl4 is what is mostly in the solution, after doing the bromate hydrolisis and filtration?. Would that be a very suitable salt to further purify by iterative re-crystallization or not really?. :?: :shock:


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## Lou (Jul 29, 2011)

No, and why purify it when it's already pure enough?

PtCl4 (a Lewis acid) is very soluble in water and can only be driven from it by concentration and slow addition of diethyl ether.


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## HAuCl4 (Jul 29, 2011)

Well it isn't 6N, that's for sure. :lol:

So the K2PtCL6 is the best salt I assume.


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## Lou (Jul 29, 2011)

That's where zone refining comes into play.


Lou


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