I have sulfide ore containing low grade gold and other metals which i would wish to recover. What is the best process?


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rickharris29 days ago

A link to the Cody! Nice one!

I'm impressed by the results this guy gets, using ugly, homemade equipment.

Although, I guess in this video he is actually using two furnaces: one ugly, homemade one, and another that looks professionally made.

He isn't above using commercial equipment :-)

Yonatan2427 days ago

Check Cody'sLab on Youtube.

I think the usual technique for sulfide ores is roasting,

https://en.wikipedia.org/wiki/Roasting_(metallurgy...


which converts the sulfide (S-2) to an oxide (O-2), plus sulfur dioxide (SO2) gas.

For a noble metal like gold, you might actually get pure metal instead of the oxide, because for noble metals the metal is more stable than its oxide. Although, you say it is "low grade", so maybe that means little flecks of gold dust mixed in with the mixed oxides left over after you roast it.

By the way, if you have a lot of ore, you are probably going to want to capture the SO2 gas, and upgrade that into sulfuric acid (H2S04). I think the Wiki article on roasting mentions this. It is something akin to the "Contact process", which is the main commercial way for making sulfuric acid.

That is the frugal way to do it, a kind of a use-every-part-of-the-buffalo approach.

You could just dump it into the air. However, if you're putting large amounts of SO2 into the air, the neighbors are going to complain, because, you know, it's nasty, and it smells like a volcano, or burned matches, or like Satan is living next door to you. Ha!

https://en.wikipedia.org/wiki/Sulfur_dioxide

I'm not sure what to do with the other metal oxides, but it kind of has to be some kind reductive process, right? You know, reduce the oxide to the metal. Maybe smelting? Maybe dissolve in acid, then electrowinning?

https://en.wikipedia.org/wiki/Smelting

https://en.wikipedia.org/wiki/Electrowinning

Maybe someone reading this forum is a student of metallurgy. That is really the kind of expert you need for turning ore into metal.

https://en.wikipedia.org/wiki/Metallurgy

By the way, you might call someone who studies metallurgy, a "metalhead", but usually that word refers to a fan of the "heavy metal" music genre.

https://en.wikipedia.org/wiki/Metalhead

;-P \m/

The roasting is called cupellation ;-)

https://en.wikipedia.org/wiki/Cupellation

These two processes are not exactly the same thing, although both involve heat, and oxidizing conditions.

I think roasting is just heating in the presence of air.

https://en.wikipedia.org/wiki/Roasting_(metallurgy...


In contrast, cupelling is heating the presence of air, and lead or lead(ii) oxide (PbO).

https://en.wikipedia.org/wiki/Cupellation

https://en.wikipedia.org/wiki/Lead(II)_oxide

Also in cupelling, the temperature is high enough so the PbO, is liquid, and it can act as a solvent for other metal oxides. The Wiki page for PbO says pure PbO has a melting point of 888 C, and I am guessing its melting point might be different for impure PbO, like PbO with other metal oxides mixed into it.

Actually, somewhere in this same topic, RickHarris linked to a Youtube video of that guy, Cody, of Cody's Lab, cupelling a mixture of lead and gold.

Apparently there are special crucibles that are porous to PbO mixtures. I mean, in the video, one of these crucibles seems to soak up the PbO mixture, leaving a tiny bead of gold in the bottom of the crucible.

Although I am not sure where you go from there if there are metal oxides in the used crucible that you also want to recover. I guess you have to smash up the crucible, and use some different process on the smashed up crucible pieces.

+1

There are Hydrogen furnaces in my state (used to make mercury dental amalgam) that are a dangerous reducing sealed H2 hot atmosphere that could be used to recover metallic oxides...