Amalgamation has forever and ever, thanks to mercury, been used to recover gold, fine gold in particular.
Filter off the mercury and thallium nitrates. You should be left with gold. And now for the bad news: Hg-196, the isotope converted to gold, comprises 0.15% of natural mercury. Assuming perfect conversion to Hg-197, then after one half-life (half of the Hg-197 decays), a kilogram of mercury will give you. 0.73 grams of gold.
The gold literally is dissolved into the mercury. This allows the collection of very small sized particles of gold. At the end of the operation the mercury and gold amalgam are collected after which the two are separated, and the mercury recycled. Now larger gold and nuggets will not be completely converted (except over a very long time) and .
A mercury-gold amalgam then is formed because gold will dissolve in the mercury while other impurities will not. The mixture of gold and mercury is then heated to a temperature that will vaporize the mercury, leaving behind the gold. This process does not result in gold that is 100% pure, but it does eliminate the bulk of the impurities.
In gold placer mining, in which minute specks of gold are washed from sand or gravel deposits, mercury was often used to separate the gold from other heavy minerals. After all of the practical metal had been taken out from the ore, the mercury was dispensed down a long copper trough, which formed a thin coating of mercury on the exterior.
I was thinking I could submerge the pins in mercury (after cleaning to remove any oils) until the gold layer is dissolved, "rinse" the pins with more mercury to get all the gold, put them aside to have any mercury residue distilled off them, and repeat until the mercury gets enough gold to be worth retorting to obtain a concentrated powder with all the gold and a much smaller portion of base metals which would be trivial to refine.
Mercury is the only metal which occurs as a liquid at ordinary temperatures and is one of only two metals which occurs naturally in both its metallic and