Electrolysis is a scientific way of "splitting" substances. Electrolysis means "electric-splitting" and involves the separation of substances through an electric current. Metals above carbon in the reactivity series (potassium, sodium, lithium, calcium, magnesium and aluminium) are extracted by electrolysis commercially.
Electrolysis is used in the mining industry to split reactive metals from their ores after they are extracted (taken) from the ground. It is also used to plate (cover) things with metal because it costs less than using, for example, 100% pure solid gold to make jewelry.