Electrowinning
The extraction of a metal from a solution or molten salt of its ore by electrolysis.
Unit
kWh/kg
In depth
Electrowinning is the only practical route for metals too reactive to be reduced by carbon, and it is very energy-intensive: aluminium production alone accounts for a significant share of global electricity use. An inert anode is used since there is no pure metal to dissolve.
Examples in the real world
The Hall–Héroult process extracting aluminium from alumina dissolved in molten cryolite at 950 °C.