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How to Use Lye to Refine Gold

Lye is a common name for sodium hydroxide (NaOH) and is a strong, highly corrosive base. It's commercially available and usually sold in solid form as flakes, pellets or powder. Lye is generally mixed with water to form a caustic solution that is commonly used as a drain opener and oven cleaner. It can dissolve many substances, although some metals such as gold are resistant to its effects. Lye is therefore used to refine gold on both a small and large scale.

Things You'll Need

1 oz. mercury
2 gold pans
Copper sheet
Distilled water
Gold concentrate
Lye (1 tablespoon per pan)
Miner's magnet
Nitric acid (by the drop, as required)
Plastic bag
Pyrex measuring cup
Rubber apron
Rubber gloves
Safety goggles

Instructions

- 1
  Put on safety gear, including gloves, goggles and apron. You will be working with lye and nitric acid, both of which are highly corrosive.
- 2
  Fill the gold pan about halfway with material containing a high concentration of gold, also known as concentrates. Cover the concentrates with distilled water, add a tablespoon of lye solution and swirl it for a few minutes. The lye dissolves the dirt and oil that may be obscuring the gold particles.
- 3
  Drain the water from the pan, add the mercury and enough fresh distilled water to cover the gold concentrate in the pan. Swirl the contents of the pan so that the mercury can pick up the gold particles. The content of the pan that is not absorbed by the mercury is now known as "black sand."
- 4
  Pour the black sand into another container, leaving the mercury in the pan. Place the magnet in the plastic bag and use it to retrieve the tiny gold particles in the black sand. The gold will be attracted to the magnet and the plastic bag may then be pulled off of the magnet, leaving the gold inside the plastic bag.
- 5
  Separate the gold-laden mercury from the free mercury. Gold-laden mercury does not roll well, while free mercury rolls easily. Place the gold pan with the mercury inside an empty gold pan and pour off the free mercury.
- 6
  Pour the gold-laden mercury into the pyrex cup and add enough water to cover the mercury. Position yourself upwind and add a few drops of nitric acid until the mercury starts to fizz. Continue adding nitric acid slowly until only the gold remains.

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