n fact, there are some gold containing components on the circuit boards of electronic products such as old radios, old TVs and old mobile phones that we don’t use at ordinary times. We took the old radio apart and looked at its circuit board. There were some shiny gold parts on it. Those golden things were gold. If you have idle circuit boards, you can do some interesting experiments to extract gold.
1- wear protective equipment. Be sure to wear a mask, goggles and industrial gloves. Chemicals and acids are irritating to the skin, and even burn through the skin. The acid mist produced by combustion will also burn eyes. If inhaled accidentally, it will cause nausea.
2- purchase concentrated nitric acid. Nitric acid is a colorless chemical liquid used in various industries, steel and wood processing. We can buy nitric acid in industrial or chemical stores. (consult relevant departments before purchasing.)
3- cut the circuit board and put it in a glass container. It is better to use Corning’s Belle heat-resistant glassware or other high-temperature resistant glass containers.
4- pour concentrated nitric acid into the glass container for storing the circuit board. Acid mist will be generated in the container when pouring, so be sure to wear protective equipment.
5- stir the mixture with a glass rod until it dissolves. Nitric acid will dissolve all the plastic and metal parts of the circuit board, except gold, which needs a stronger acid to dissolve.
6- drain the acid and separate out the solid in the solution with a filter.
7- take out the parts that are not melted. These parts contain gold. There may still be some plastic left on the gold, which needs to be removed in another way. Remember to wear industrial gloves.