# Separating PMG's fro raw ore



## Opal2000 (Oct 10, 2017)

Looking for advice on the best method for separating PMG's from raw ore in the correct sequence to recover the 4 main metals concentrated in the ore.
The ore is concentrated mainly - Pd 68.9%, Ir 8.1%, Ag 6.9%, Au 5.7 % . 
Would a simple mixture of Hydrochloric acid and Hydrogen peroxide ( 20:3 ) dissolve just the Palladium from the ore or will it dissolve all? or is there a better way?
My knowledge on refining is very limited. Any advice would be great.


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## patnor1011 (Oct 10, 2017)

What else is present in the ore concentrate? What method was used to concentrate ore? What are the results of assay?


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## Lino1406 (Oct 11, 2017)

I am not sure about the limit to gold dissolution. If it is 20:3 than positive


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## 4metals (Oct 11, 2017)

> The ore is concentrated mainly - Pd 68.9%, Ir 8.1%, Ag 6.9%, Au 5.7 %



This is more of a concentrate than a raw ore as just shy of 90% is metal according to your assay. In any event you essentially have 75% of your metal, palladium and silver, which are soluble in nitric. The Iridium and Gold are insoluble in nitric. 

Have you tried parting a sample in 50% nitric acid and 50% distilled water? No sense making this more complicated than it need be.


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## g_axelsson (Oct 11, 2017)

Opal2000 said:


> Looking for advice on the best method for separating PMG's from raw ore in the correct sequence to recover the 4 main metals concentrated in the ore.
> The ore is concentrated mainly - Pd 68.9%, Ir 8.1%, Ag 6.9%, Au 5.7 % .
> Would a simple mixture of Hydrochloric acid and Hydrogen peroxide ( 20:3 ) dissolve just the Palladium from the ore or will it dissolve all? or is there a better way?
> My knowledge on refining is very limited. Any advice would be great.


Is this really an ore concentrate? To me it feels very strange to not see any platinum. Most Australian PGM ores have palladium to platinum concentrations of 2:1.5. Only one deposit mentioned any relevant levels of iridium.
http://www.australianminesatlas.gov.au/aimr/commodity/platinum_group_elements.html

If this is an ore then the chemical form of minerals present could create some problems, for example silver chloride, silver sulfide or gold telluride could make it harder to process. Roasting might be required as a first step but beware of the gases as they could be lethal, especially if there is any arsenic in the concentrate. Even silver chloride is volatile and poisonous when roasted. Proper ventilation and dust filters are needed to do it safely and to catch any values literary going up in smoke.
The physical form would also affect the process, does the concentrate come as fine particles or as nuggets? If it is a fine particle concentrate then it could probably be leached quite simple in acid as it is while larger nuggets might need hours or days of boiling acid to dissolve properly.

With the above composition and values, the silver is more of a nuisance, no concern should be taken to the recovery of silver as the value of it is minimal compared to any of the other metals. If it could be recovered after the other metals are collected then it's okay and an added bonus, but it should not be of primary concern.

Just as 4metals suggest, I would advice on making a number of tests on smaller samples to see what dissolves. And as we say here on the forum, you never lose your precious metals unless you throw it away. A proper stockpot, saving any filters and testing along the way to follow your precious metals will help you keep any precious metals that comes through your door.

Finally, if you are not an expert on refining, maybe this is something best handled by an outside expert. PGM refining isn't the easiest thing to do.

Göran


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## 4metals (Oct 11, 2017)

Perfect application for a soxhlet extraction


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## Topher_osAUrus (Oct 11, 2017)

Soxhlet extraction, awesome!

https://youtu.be/qiRBLfezuxs

A great video about them by NurdRage -I hate how he modulates his voice, but, apparently he didn't want people to find out that hes like 16 with a PhD. (He is nilered -the keen observer will notice many many coincidences that are statistically impossible without them being one in the same person) 

Anyways, that video has some good tips on using them, like what to do to prevent clogging the evacuation siphon, etc..


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## lazersteve (Oct 16, 2017)

The problem with the Soxhlet is the batch size you can run. Unless your feed stock is already very concentrated, you will be extracting for quite some time to get the goodies inside. I have several Soxhlet extractor set ups, the largest is almost 2" in diameter and 24" tall. I do not have a great need for them, but they were part of some extraction experiments I ran nearly 10 years ago.

They are great for extracting small quantities of a desired material from a larger feed stock with minimal solvent.

Cool stuff for sure!

Steve


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## Yggdrasil (Jan 16, 2018)

I'm just curious here.

Will AR survive destillation?
I'm wondering if it is doable to use AR as solvent in a Soxhlet extractor?
I guess it will revert back to azeotropic consentrations of each of the acid.
Or will one of them keep their strength better than the other?
The upside is that there will be no need for filtering and such, and downside will of course be batch size.
But for the hobbyist it may seem tempting ;-)

One can even arrange for a steady drip of Nitric from the top of the reflux column and start with pure HCl.

Are there any other of the solvents we ordinary use, 
that are more suitible for Soxhlet extraction than others?

I think sufuric will be only for the ones, that are equipped to handle the temperatures and hazards related to boiling sulfuric, if anyone dare to use it this way at all.


Any thoughts anyone?


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## Rougemillenial (Feb 6, 2018)

Yggdrasil said:


> I'm just curious here.
> 
> Will AR survive destillation?
> I'm wondering if it is doable to use AR as solvent in a Soxhlet extractor?
> ...


 I highly doubt that AR will survive distillation as the components react with each other to make nirosyl chloride among other things which the rate increases with temperature. However assuming you did the extraction under vacuum, you could be able to do it as the boiling point would drop enough to slow down decomposition.


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