# Chlorine leach of refractory gold ore



## AJLnz (Sep 28, 2020)

I have a problem.
I used 35% hydrochloric acid and 15% sodium hypochlorite acid on a roasted refractory gold ore directly.
The ore was roasted at 650 degrees C for half an hour and cooled before it was submerge with acid mix. Kept it in for 4 hours and adding 15ml sodium hypochlorite every 20 minutes to keep oxidation at 1100mV. No heat added.
Precipitated with metabisulfide mixed in water.
Solution was a nice yellow and turned dark blood orange and back to yellow.
After an hour it turned milky white and dropped, it has some light brown streaks floating on top and some brown dust at the bottom. please see photos.


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## fishaholic5 (Sep 29, 2020)

Your Gold is in the precipitate, it's common to get precipitation in two parts like this with dirty solutions or first drops from leaching ore.
The lighter Precipitate is usually from drag down of other metals with the Gold or can be from excess precipitant.

Cheers Wal


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## AJLnz (Sep 29, 2020)

Thanks Wal
Just worried that I got it wrong, never done ore before.


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## fishaholic5 (Sep 29, 2020)

You are welcome, there are other members of the forum that have extensive experience with leaching ores that can probably explain it better.
Check Deano's posts here for more info on leaching methods.

Cementing the remaining solution with Copper will recover any precious metals left in Solution.

Cheers Wal


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## Ali (Feb 17, 2021)

I think the yellow color, in the beginning, is due to the formation of Sodium Sulphide, then after a while, it gained oxygen from the atmosphere, turned into Sodium Sulphate with its white color. obviously, the heating process wasn't enough to get rid of sulfur.


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## Lino1406 (Feb 17, 2021)

Sorry there is no mechanism for obtaining sodium sulphide in that environment. Yellow color comes mostly from iron and in best case from gold


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## Ali (Mar 2, 2021)

No need to be sorry, and for the others sorry for the inconvenience, it's sulfite, not sulfide.


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## Rick & Carrie (Apr 4, 2022)

AJLnz said:


> I have a problem.
> I used 35% hydrochloric acid and 15% sodium hypochlorite acid on a roasted refractory gold ore directly.
> The ore was roasted at 650 degrees C for half an hour and cooled before it was submerge with acid mix. Kept it in for 4 hours and adding 15ml sodium hypochlorite every 20 minutes to keep oxidation at 1100mV. No heat added.
> Precipitated with metabisulfide mixed in water.
> ...


Have you melted the precipitate into a bead yet?

If you have, the refining methods on this site will allow you to refine the dore you produced with your procedures.


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