Did you know that gold is used to bind components in computers, tablets, cameras, and other devices? A standard smartphone contains around 0.2g of gold, which works out to about £1.80 in your pocket.
The SIM card, the motherboard, and the smaller components on the back of the LCD panel contain most of the gold in phones, and the precious metal is relatively easy to remove. Older electronics might even have more gold in their composition.
Removing the boards
In a glass vessel, put your circuit boards. Combine two parts hydrochloric acid and one part hydrogen peroxide in a separate bottle (a concentration of three per cent). Pour the mixture over the circuit boards and submerge them entirely. Wait a week, stirring the vessel with a glass or plastic rod every day. The acid will blacken across time and gold flakes will fall off the scraps.
Collecting the flakes
Move the mixture to a second glass jar after passing it through a coffee filter. The flakes of gold will be left behind. Fill a deep plastic tray halfway with water with the remaining circuit board pieces. Save any pieces that still have gold on them for re-dipping.
Wash the pieces with water after pouring the water through the filter to collect some gold dust. They should be washed in methanol, then rinsed with water to remove any residue.
Heat a clay bowl with a blowtorch while wearing protective and flame-resistant clothing, boots, and goggles. Borax allows the gold to melt at temperatures lower than 1,064 degrees Celsius. Apply the gold flakes as the borax starts to soften. Heat until the flakes have melted together to form a gold bead. Allow it to cool completely before removing the gold from the re-solidified borax.