# Refining or smelting gold tailings from mercury amalgamation



## diego.molina311 (Feb 24, 2022)

Hi all,
Does anyone have any experience refining or smelting gold tailings from mercury amalgamation? Since this process was done artisanally by someone else, recovery for the amalgamation was quite low and a good chunk of the gold content wound up in the tailings.

I am wondering what type of plant could process this material. Could a CIL/CIP refinery or Copper Smelter process this? The volume is significant enough to make it economically viable to move the material as long as the receiver can recover the gold units.

For your reference, the independent assays from a tier one lab are as follows:

Au: 17.2 g/t
Ag: 74 g/t
Cu: 0.18%
As: 0.072%
Hg: 104 ppm
SiO2: 75.38%
Insol: 79.32%
S (total): 4.69%
Fe: 8.67%
Pb: 0.049%
Zn: 0.032%
Cl: < 20 ppm
F: 193.9 ppm
Al: 1.60%

Thanks,
D


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## orvi (Feb 24, 2022)

With this Au content... It will be difficult. Would be complex pyrometallurgical task to do that = like any other hard rock mining of complex ore.
If the gold cannot be recovered by gravitational means (shaker table/sluicing) the likely option would be to make flotation concentrate, which could be then smelted in some way...
Or cyanide bath, if the gold isn´t locked inside matrix/sulfides and mix is sufficiently milled.

Any way used, 104g Hg per ton is very significant ammount. If this is meant to be processed responsibly, awful ammount of toxic waste will be produced and should be disposed of. 

I will personally take hands off such material.


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## BlackLabel (Feb 25, 2022)

Depending of the amount of your material, you could build a large retorte. Put in maybe 100 kilograms, heat it up, evaporate the mercury, condense and recover it. If you got about ten grams of mercury, you can consider the material as "free of mercury" and proceed refining the values.


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## squiggles (Feb 25, 2022)

What's the grain size ? Like beach sand ? Or fine like clay ?


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## slsmp40 (Feb 26, 2022)

diego.molina311 said:


> Hi all,
> Does anyone have any experience refining or smelting gold tailings from mercury amalgamation? Since this process was done artisanally by someone else, recovery for the amalgamation was quite low and a good chunk of the gold content wound up in the tailings.
> 
> I am wondering what type of plant could process this material. Could a CIL/CIP refinery or Copper Smelter process this? The volume is significant enough to make it economically viable to move the material as long as the receiver can recover the gold units.
> ...


How many ton of this do you have? Unless it’s a 100+ the juice isn’t worth the squeeze really. You would be better off paying for someone to take away your toxic waste. You said someone else did it, give it back and get the hell away from them. Unless you want the Mercury exposure. Nice and finely divided so it can vaporize really good. Perfect.


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## diego.molina311 (Feb 28, 2022)

slsmp40 said:


> How many ton of this do you have? Unless it’s a 100+ the juice isn’t worth the squeeze really. You would be better off paying for someone to take away your toxic waste. You said someone else did it, give it back and get the hell away from them. Unless you want the Mercury exposure. Nice and finely divided so it can vaporize really good. Perfect.


Thanks for the response. It's > 1,000 wmt. At least half of it is > = 20 g/t, so definitely not an insignificant amount of contained gold.


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## diego.molina311 (Feb 28, 2022)

squiggles said:


> What's the grain size ? Like beach sand ? Or fine like clay ?


I dont have a proper sizing test, but it's more similar to "beach sand sizing" than fine clay.


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## diego.molina311 (Feb 28, 2022)

orvi said:


> With this Au content... It will be difficult. Would be complex pyrometallurgical task to do that = like any other hard rock mining of complex ore.
> If the gold cannot be recovered by gravitational means (shaker table/sluicing) the likely option would be to make flotation concentrate, which could be then smelted in some way...
> Or cyanide bath, if the gold isn´t locked inside matrix/sulfides and mix is sufficiently milled.
> 
> ...


Thanks for the feedback. Yes, concentrating the material is definitely an option. Do you have any experience floating mercury amalgamation tailings and thus on what recovery I may be reasonable expect to get?


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## squiggles (Feb 28, 2022)

In what country are the tailings located ? Can you get a licence to use cyanide there ?


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## Geo (Mar 5, 2022)

A commercial retort will allow you to remove the mercury from the metals and collect the mercury for resale or proper disposal. There are plans on the internet on how to build a retort and operate it.


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