Acid Digestion Test of Gold

[nyalee]

can you please help, what is acid digestion test of gold? How is it performed and which chemicals do I use?

 

[Eamonn]

Hi Nylee
I know what acid digestion is and I know what a gold test is but not sure what you mean by "Acid Digestion Test of Gold"
If you explain what you want to do you may get a useful answer.

 

[nyalee]

hie Eamonn

I am doing a research on the processing of refractory gold and part of the research I have to do cyanide leaching to prove that the gold is refractory and also an acid digestion test which helps prove that the gold is refractory. Refractory gold in simple is gold that cannot be extracted through conventional means i.e through cyanide leaching because the recovery rates are very very low.
My problem is I do not know what is acid digestion test and how do I perform it on gold

 

[Eamonn]

Hi Nyalee
I don't know a lot about gold extraction from ore but there are experts on the forum that can give you better advice that I could.
I'm sure they will comment.
Eanonn

 

[g_axelsson]

I just did a quick googling on the topic. It seems there is a procedure called "multi-acid" or "4-acid digestion".
http://www.sgs.com/en/mining/analytical-services/geochemistry/digestion-and-fusion/multi-acid-4acid-digestions

Göran

 

[goldsilverpro]

hie Eamonn

I am doing a research on the processing of refractory gold and part of the research I have to do cyanide leaching to prove that the gold is refractory and also an acid digestion test which helps prove that the gold is refractory. Refractory gold in simple is gold that cannot be extracted through conventional means i.e through cyanide leaching because the recovery rates are very very low.
My problem is I do not know what is acid digestion test and how do I perform it on gold

I couldn't find any info concerning a specific method called "acid digestion test" for refractory ores.

Some quotes from the internet concerning refractory gold.

Refractory gold = "Physical encapsulation of disseminated gold particles (usually less than a few micrometers in size) within a mineral that is unreactive and impervious to leaching."

"These refractory ores require pre-treatment in order for cyanidation to be effective in recovery of the gold. A refractory ore generally contains sulfide minerals, organic carbon, or both."

"A refractory ore generally contains sulfide minerals, organic carbon, or both. Sulfide minerals are impermeable minerals that occlude gold particles, making it difficult for the leach solution to complex with the gold."

 

[Grelko]

I couldn't find any info concerning a specific method called "acid digestion test" for refractory ores.

By the off chance, could an "acid digestion test" just mean, to dissolve the gold into AuCl3 or other forms? (dissolving gold with an acid)

Or perhaps a stannous test?

Edit - Could it be a "leachability test", or something like these?

http://www.caslab.com/RoHS-WEEE-Acid-Digestion/
https://www.911metallurgist.com/blog/diagnostic-gold-leach-test-work/6-nitric-acid-digestion-gold-leachability-test

 

[Lino1406]

It means maximizing gold leachability by e.g. grinding the sample, using stronger conditions in order to get max assay. Since what is the use if it is blocked inside and you can't reach it

 

[SaltwaterServr]

New here, like within the last 10 minutes new, but I think he's referring to the old school method of oxidation then dissolving with acid finalized by precipitation/cementation of the gold. Basically what the old miners did before cyanide made it across the Pacific.