ECS Classics: Hall and Heroult and the Discovery of Aluminum Electrolysis

Asimultaneous invention of an important industrial electrochemical process by two men on two different continents appears improbable. Yet that is what happened. One was in the United States and the other in France. Each inventor was born in the same year, 1863, and at age 22 each independently developed the same technology to produce aluminum by electrolysis. They were rather different personalities. Charles Martin Hall1-4 was born into an educated family and attended Oberlin College. He was a studious scientist who deliberately, step by step, arrived at his process. The father of Paul Louis Toussaint Héroult6-8 was a tanner and Paul Héroult was expected to continue in that business. Instead, he attended a school of mines where he was dismissed after the first year because he spent his time thinking about how to produce aluminum rather than his studies. He was more of an intuitive thinker, and on inspiration, first electrolyzed alumina in molten cryolite in his father’s tannery. The technology of these two inventors is now known as the HallHéroult Process. Hall and Héroult were among the earliest members of ECS, then named “The American Electrochemical Society.”