How we can seperate pt and gold

[nizi72]

Hi
Respected members plz guide how we can seperate pt and gold alloy??

Many thanks
Javed

 

[4metals]

Dissolve the alloy in aqua regia and deNox with sulfamic acid. Then filter and drop the gold with ferrous sulfate. This precipitant will assure you that the Platinum remains in the same valence state allowing the next reaction to be more effective. Precipitate a warmed solution with a warm solution of water and saturated ammonium chloride. This will precipitate the platinum as ammonium chloroplatinate. Filter out the salt and rinse it with a dilute solution of ammonium chloroplatinate as the salt is slightly soluble in water.

Be careful around platinum group metal salts as exposure to the salts is dangerous to your health. Wear all the PPE you can. Research the effects by googling Platinosis.

 

[FrugalRefiner]

Filter out the salt and rinse it with a dilute solution of ammonium chloroplatinate as the salt is slightly soluble in water.

I believe 4metals meant a dilute solution of ammonium chloride for the rinse.

Dave

 

[4metals]

I believe 4metals meant a dilute solution of ammonium chloride for the rinse.

Yup, sorry, ammonium chloride. I use a 7 to 10% solution. I just dilute some of the saturated solution left over to get me in the approximate range.

 

[Shark]

What does the ammonium chloride remove from the precipitate? I have never worked with platinum other than cement it for later.

 

[orvi]

What does the ammonium chloride remove from the precipitate? I have never worked with platinum other than cement it for later.

Low concentration electrolyte still has potency to dissolve some of the impurities. Technically, if solution only contain Au and Pt, then obviously there would be nothing much to wash out. But in utmost simplicity, it help you to suck all of the mother liquor after NH4Cl precipitation of Pt. You cannot effectively do it with plain H2O, because it will dissolve some of the Pt salt. From my experience, if you are working in fair concentrations of Pt (more than 50g/L), it is sufficient to use 5% solution of NH4Cl (roughly 1 M - molar) and it will drag very little Pt with it compared to bulk processed. You will always cement waste streams, so you get it in the end.
Other story is if you have base metals or other impurities to deal with in solution. And we do not forget about Fe from ferrous sulfate, we used for precipitation of gold. But yeah, Fe is very easy to remove in most cases.

 

[Shark]

Thanks, that makes sense.

 

[CosmoIridium]

No need to separate or remove Pt from your Au, I will buy it as is. I will pay according to the % of each metal.

 

[nizi72]

What does the ammonium chloride remove from the precipitate? I have never worked with platinum other than cement it for later.

 

[nizi72]

Many thanks for all the guidance and your valuable time to reply.

 

[lala4317]

No need to separate or remove Pt from your Au, I will buy it as is. I will pay according to the % of each metal.

Do u still buy these

 

[Xing]

how abou the content of each metal in the alloy, dissovle all into solution, sovlent extraction for gold with DBC, then stripping by oxalic acid to gold powders.