Purify gold with mercury. This is an ancient method of purifying gold. As long as you have patience, you can say that the purity is high. The method is as follows:

1, amalgam method: gold+mercury+water; Gold and mercury will not form intermetallic compounds until no gold particles appear.

2. Sulfur: mix and grind sulfur powder and amalgam.

3. Heating in air: at this time, excess mercury evaporates, and the base metal first forms metal sulfide, and then forms metal oxide.

4. Repeat this operation for many times.

5. Borax: The base metal oxide reacts with borax to generate low melting point substances floating on the liquid, and the bottom is pure gold.

Note: This method is used to prevent mercury vapor poisoning. In ancient times, because there were no chemicals such as nitric acid and sulfuric acid, the above methods could only be used.

Extended data:

Gold is the elemental form of chemical element Au, and it is a soft, golden yellow and corrosion-resistant precious metal. Gold is a rare, rare and precious metal. In the world, gold is usually measured in ounces. In ancient China, people used "two" as the unit of gold, and gold was a very important metal.

It is not only a special currency for reserve and investment, but also an important material in the fields of jewelry, electronics, modern communication, aerospace and so on. After 20 15, the international gold price soared. In new york, the price of gold rose from $65,438+$0.200 per ounce to $65,438+$0.300 in less than a month. According to statistics, since 20 15, the price of new york gold futures has increased by 9.3%.

References:

Baidu encyclopedia-gold