Non-Chemical separate gold and platinum by specific gravity

[platinumsmith]

Hi there, what a great website. (my first post and visit)
I have a question.
Is it possible to separate gold jewellers filing from platinum filings by using their difference in specific gravity?
I was guessing that since platinum is heavier it should sink to the bottom of a soloution etc.
Is there a particular solution that would work best for this?
If so is there some technique to perform it succesfully / more effectivley.

I ask this as I have a large quantity of platinum lemel (filings) with small amounts of gold in it. I would prefer not to refine the whole lot back to pure gold and pure platinum as the platinum is already alloyed etc.
any ideas?

 

[Harold_V]

I ask this as I have a large quantity of platinum lemel (filings) with small amounts of gold in it. I would prefer not to refine the whole lot back to pure gold and pure platinum as the platinum is already alloyed etc.
any ideas?

Incinerate completely, eliminating all traces of carbon.

Boil everything in dilute nitric.

Rinse well.

Dissolve the gold alloy with COLD AR. (That limits the ability of AR to dissolve platinum).

Separate the gold laden solution from the solids, and rinse the solids well.

Wash the remaining solids in ammonium hydroxide (to eliminate traces of silver chloride).

Rinse the remaining solids well.

Melt.

Roll, to determine if the material is brittle, or not. If you fail to remove all the silver, you can expect the platinum alloy to be brittle.

You will have traces of undesirable material present after all of these processes. With luck, they will be removed in melting. Personally, I wouldn't reclaim the filings for use, but it can be done successfully.

Process the gold solution to recover the values, using conventional methods.

Got questions? Read Hoke.

Harold

 

[platinumsmith]

G'day Harold,
thanks for the tips.
I was actually reading Koke's book this morning and learnt about silver Chloride.
Seems like it should work OK.
Thanks again.