Help with recovery of Pt, Pd and Rh from quartz ore

[Idaho]

Hi Guys,
My first post here.

I am working material in milky to rose colored quartz that has almost equal amounts of Au, Ag, Pt, Pd, Rh. There is a lot of Pyrite and Fe.

Up until recently I have only been after the Gold and Silver and I was never too concerned with recovery of the Pt, Pd or Rh, but after an extensive fluorescent spectrometry assay of the ore I have decided I really needed to look into recovering these metals.

Can anyone point me in the right direction? I have read some of Hoke's stuff on refining noble metals, but to be honest most of it is over my head. I never was very good at chemistry.
Is there a "simple" way to fire assay any of these noble metals?

Also, does anyone know if it would be possible to recover the Pt, Pd, and Rh from the slag(wastes) and old cupolas from when I was making gold and silver buttons?

Thanks for any help
P.S. love this forum, been lurking for a couple of years...

 

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[vpnavy]

Can't answer your question (I am sure a member will jump in shortly) but did notice this was your very first post. So, Welcome Aboard! If you haven't already - don't forget to take a look at Sub-Forums: Idaho for information (i.e., clubs, etc.) directly related to your state.

 

[aussco999]

Hey Idaho:

You must have a rare ore that contains an almost equal amounts of precious metals. As your list of metals don't normally run together equally. A high percentage of Fe may give you a PGM false/positive when using a fluorescent spec assay, so it's a good idea to have a fire assay done by a qualified assayer.

Mrs. Hoke wrote a great book on “Refining precious metal wastes”, but she was dealing with refined/scrap metals. You have head ore and the chemistry will be a lot different. Maybe a better book to review would be “Recovery and refining of precious metals” by C.W. Ammen, Second Edition. He covers a lot more details of ore treatment and metal recovery methods.

And, speaking of chemistry, you're going to have to get better at it. Unless you can produce a concentration with a gravity system, then some form of chemistry will be needed. Even floatation needs some chemical knowledge and lixiviation requires a lot more.

If Charles Butler of Butler Labs, Bodfish, CA is still around, he had a handy DIY method of simple fire assaying using common tools/torches you might find in your garage. It was easily adaptable for field use and accurate enough to give you a “yea or nay” answer of precious metals in your ore.

Fire assaying PGM's isn't difficult, but should be done in a glazed crucible for accurate results. You can try one of the general purpose fluxes sold at the mining stores or have a custom flux made for your ore. To improve Pt and Pd recovery always inquart with silver, and to improve the Rh recovery, inquart the gold. Have an AA or an emission spectrometry analysis done on the prill to confirm PGM's amounts, but ignore the Au/Ag as they're used as collectors in this type of assay.

I won't get into the chemistry requirements for now, but will let you know it can't be done on a shoestring budget. You'll have to spend a few $1K (equip, chemicals, environment) to do anything more than lab size samples and chemistry will have to become second nature to you.

I guess the real question for now is; as a reasonable and prudent man, do you have high enough real values in your ore to make a profit (after spending a bunch of money) to go after the PGM's? I'm starting to see more posts on PGM's, but most are based on a stone/scratch test for jewelry which is useless on ore. Your previous assay method is proven, but can be overwhelmed by some base metals, so a fire assay is your best bet.

If this is more than just a hobby to you and you're trying to make some retirement money, let me know as I and probably some others that have done it before will get you heading in the right direction. FYI, crushing and leaching old used crucibles and cupels for lost metals has been around forever. I think Hoke mentions it in her book. I may have to break down and reread that book in my spare time.

Good luck on your project,

John

 

[Idaho]

Thanks John,

I spent the day at the Assayer's office today, doing both fire assays and several more fluorescent spectrometry tests and I think I have a solution that will work for both my lack of chemistry and being quite cheap.

The assayer I use is hooking me up with a refiner, that will buy the heavies from me after I have removed the visible gold and silver. I guess besides the PGM's they are interested in the smaller amounts of Eu (Eu= 3.86%) and Nb(Nb=4.94%), that are showing up in the FSA tests. I am sending the refiner
a sample, they want a 5 gal bucket of heavies to test.

John, The day I decided to become a miner I stopped being "Prudent and Reasonable" ;-)
But I do understand what your saying.
Thanks for your help.