The modern method of commercially producing aluminum…
1886 CE
The modern method of commercially producing aluminum is discovered by Charles Martin Hall, a student at Oberlin College in the United States, and French metallurgist Paul-Louis-Toussaint Héroult, working independently of one another, almost simultaneously in 1886: electrolysis of purified alumina (Al2O3) dissolved in molten cryolite (Na3AlF6).
They obtain patents in the USA and France, respectively.
The process is entirely dependent on the new availability of cheap hydroelectric power.