Deano, will this also drag down any copper, silver, or other metals? How can you make it drop gold only?Deano said:Both sylvanite and calaverite can be dismantled by leaching with 12% nitric acid overnight at room temperature.
Occasionally there will be impurities present which will require a longer leach time, I usually give it 24 to 48 hours being sure that minimal evaporation takes place.
The gold will be suspended in the leach solution virtually as atoms and will pass straight through a filter paper.
If you add an equal amount of 1:4 aqua regia to the beaker as to the volume of the original leach you will dissolve the gold almost instantly.
You now simmer the beaker of liquid until the fumes evolved change from orange/brown to white.
Give it another 5 minutes on the hot plate to drive off any residual nitric fumes.
Take it off the hot plate and let it cool down in the fume cupboard before filtering.
Your gold is now present in the filtrate as gold chloride, it will respond to all the standard analytical methods such as AAS etc.
Deano
Deano said:Both sylvanite and calaverite can be dismantled by leaching with 12% nitric acid overnight at room temperature.
Occasionally there will be impurities present which will require a longer leach time, I usually give it 24 to 48 hours being sure that minimal evaporation takes place.
The gold will be suspended in the leach solution virtually as atoms and will pass straight through a filter paper.
If you add an equal amount of 1:4 aqua regia to the beaker as to the volume of the original leach you will dissolve the gold almost instantly.
You now simmer the beaker of liquid until the fumes evolved change from orange/brown to white.
Give it another 5 minutes on the hot plate to drive off any residual nitric fumes.
Take it off the hot plate and let it cool down in the fume cupboard before filtering.
Your gold is now present in the filtrate as gold chloride, it will respond to all the standard analytical methods such as AAS etc.
Deano
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