# Leaching of ore with oxides and sulfides of PGMs.



## Cunano (Mar 7, 2022)

What do you recommend for leaching ore with oxides and sulfides from PGMs.?

Rgds.


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## Yggdrasil (Mar 7, 2022)

Cunano said:


> What do you recommend for leaching ore with oxides and sulfides from PGMs.?
> 
> Rgds.


I might be wrong, but to me that seems to be seriously lacking on info. 

It is in the class how long is a rope......

What kind of ore and in what shape, what else are in the ore, some pictures and assays would help.
Regards Per-Ove


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## orvi (Mar 7, 2022)

Roasting and smelting = leaching with molten lead, borax and soda  I think you will run in to problems trying to chemically leach PGMs from ore. Minimally, oxides of PGMs behave completely different than metal itself. If you want to do acid leach, you will have serious troubles to get useful recovery percentage. 
We do not know what other gangue is present and also what is the PGM composition in the ore. How rich it is etc.
Considering how much liquid waste it would produce to "effectively" leach few kilos of ore... This is the reason no big guy is doing it that way. And for what cost and recovery rate, you have it underlined: don´t pour acid on ore to expect magical values leaching. 

Of course, you can grind it and cover with some acid or other leaching agent... In my early days, i once tried "acid leach" on gold/quartz ore. I pulverized about 1/2 kg of ore, covered with HCl inside of small 3L plastic canister and start adding teaspoons of calcium hypochlorite in. Cap, shake, observe if chlorine is adsorbed into the solution (negative pressure inside the canister)... After like 5 spoonfuls it get saturated. Sitting for 2 days, i was full of hope to recover good ammount of gold. 
But I failed to even test the gold with stannous, it was so diluted. And this was ore running about 3oz/ton. Rich stuff. Gold purity exceeding 90%, i was sure that acid would have no problems dissolving it from the matrix.
Just quartz, gold and bit of pyrite/sulfides, no more than teaspoon for kilo of ore. No results whatsoever.


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## fishaholic5 (Mar 8, 2022)

I find lead isn't the best collector for PGM's. If you wish to use a collector a combination of Silver and Iron is possibly the best route.
It will achieve a seperation of most of the gold, palladium and some platinum and Rhodium with the Silver. The rest of the PGM's will be left in the slag..
This isn't really practical for large scale processing of ore, it works well on concentrates.
Leaching of oxidised ores is achievable with Chloride leached but the presence of Sulfides will use an excess of acids.
Sulfides can be oxidised using a pre leaching step using NaOH, see Deano"s posts there are details there.
If the PGM's are as PGM oxides Palladium in particular can be very hard to leach.unless it is converted to the metal or a compound that is leach soluble.

Whatever you do, make sure you know what else is in the ore, Tellurides, Mercury, lead and Arsenic in particular all pose their own headaches for processing, health and environmental problems as well as waste disposal.

Cheers Wal


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