sample preparation

[Tommy]

Hi everybody, was just wondering if anyone ever used nitric acid to pre wash the raw sample, discard and then move to the AR? sample is fully panned powder. I would think to remove impurities so that only precious metals remain.

 

[galenrog]

Sample of what, specifically?

Time for more coffee.

 

[Tommy]

Crushed and panned sedimentary rock mostly slate with gold deposits. Trying to purify the gold using AR, but was thinking of removing some material with nitric, and then after a wash proceeding to AR. Still using 3to1 and not dripping.

 

[Yggdrasil]

We do not recommend using acids on rocks.
At least not until one have a full assay.
For rocks, crusching, panning or tabling is the preferred method.

 

[Martijn]

We do not recommend using acids on rocks.
At least not until one have a full assay.
For rocks, crusching, panning or tabling is the preferred method.

The sample is fully panned powder, so I assume all rock and light stuff is gone.

Crushed and panned sedimentary rock mostly slate with gold deposits. Trying to purify the gold using AR, but was thinking of removing some material with nitric, and then after a wash proceeding to AR. Still using 3to1 and not dripping.

Then there is the question how pure is the gold and can AR dissolve it without inquarting.
Which material do you want to remove?
Loose particles or base metals alloyed with the gold?

If silver is the main alloy component besides gold, Both AR and a Nitric pre wash will likely not work, another option is to hammer the pieces flat and let the acid reach the inside of the gold better that way.

The best way imo is inquarting and then nitric, but read and study before you do! And ask us before you execute your well prepared plan please.

Iron can be taken out of the concentrates with a magnet.

Martijn.

 

[Ronei]

I haven’t used nitric acid for that, but it sounds like it could help clean out impurities.

 

[Tommy]

Thanks for the replies. Inquarting is the making of alloys no? I looked up the process and I need to study more.

 

[Yggdrasil]

Thanks for the replies. Inquarting is the making of alloys no? I looked up the process and I need to study more.

No, it is adding an amount of Nitric soluble metal to a Gold alloy so the Gold content end up at 25% (quart)
Then you can dissolve the base metals with Nitric(Parting) and and up with pure(ish) Gold that can be dissolved in AR.

 

[Yggdrasil]

The sample is fully panned powder, so I assume all rock and light stuff is gone.


Then there is the question how pure is the gold and can AR dissolve it without inquarting.
Which material do you want to remove?
Loose particles or base metals alloyed with the gold?

If silver is the main alloy component besides gold, Both AR and a Nitric pre wash will likely not work, another option is to hammer the pieces flat and let the acid reach the inside of the gold better that way.

The best way imo is inquarting and then nitric, but read and study before you do! And ask us before you execute your well prepared plan please.

Iron can be taken out of the concentrates with a magnet.

Martijn.

Panned, alright but not clear how well panned.

 

[goldshark]

The preferred method is to smelt the powder, recover the bead, then do the chemical refining/analysis. Way too many variables to do a wet analysis. If you are very proficient in mineralogy and chemistry, a bottle roll with cyanide is a much better procedure than dumping a bunch of acid into the unknown powders.

 

[Tommy]

Regarding the unknown powders, samples tested + for gold with a spectrometer.

 

[Yggdrasil]

Regarding the unknown powders, samples tested + for gold with a spectrometer.

Yes, but are they tested for Arsenic, Thallium, Cadmium, Mercury or other nasty stuff?