Dissolving gold from metal scrap or electronic waste which you can find inside personal computers is performed by using hazardous chemicals known as Aqua regia.
These chemicals are dangerous for human health and serious threat for the environment so you must be very careful in the process of dissolving gold using them.
As we spoke earlier gold is noble metal which means that gold has resistance on corrosion and oxidation unlike other base metals.
Because of that for dissolving gold we must use highly corrosive media.
Aqua regia is most common reagent for dissolving gold from other gold plated materials or even from gold-bearing ores. Aqua regia is mixture of three parts of concentrated hydrochloric acid (HCl) with one part of concentrated nitric acid (HNO3).
To increase dissolution rate of gold into these acids you can add a certain amount of hydrogen peroxide.
Main drawback from this process of dissolving gold in Aqua regia is nitric oxide (NO) gas which represents a major threat for the health and safety for the human. This is the reason why you need to be extremely careful.
The gold dissolved in Aqua regia becomes chloroauric acid, an inorganic compound with the formula HAuCL4. The pale yellow compound that is a product of dissolving gold is just one step further for extracting 24 carat of gold from.
Once again we must warn you to be very careful in using Aqua regia for dissolving gold.