Electrowinning (or electroextraction) is a process of whereby metals, such as gold, silver and copper,are recovered from a solution by means of electrolytic chemical reaction. This takes place when an electric current is passed through the solution. During the process, electrons from the electric current chemically reduce the metal ions, to form a solid metal compound on the cathode (the negatively charged electrode). The metal is deposited in a form that can be readily smelted easily into a more usable form. The metals will frequently have been put into the solution, from the ores, using a leaching process.
Electrorefining using a similar process of electrolysis to remove impurities from a metal.