Paul Héroult

The Hall–Héroult process is the electrolytic method for producing aluminum from alumina (aluminum oxide), independently developed by Paul Héroult in France and Charles Martin Hall in the United States, both in 1886. The process remains the primary industrial method for aluminum smelting worldwide and transformed aluminum from a precious metal into a widely available material.

Héroult was 23 years old when he patented the electrolytic aluminum smelting process in 1886. Remarkably, Charles Martin Hall, who independently arrived at the same process in the same year in Ohio, was also 23, making their simultaneous discovery one of the most famous coincidences in the history of metallurgy.

Yes, Héroult also developed the electric arc furnace for steelmaking, which became a fundamental technology in the steel industry and is still used worldwide. This invention expanded his legacy beyond aluminum production into one of the most important processes in modern metallurgical engineering.

Despite their simultaneous and independent discovery of the same aluminum smelting process in 1886, Héroult and Hall reportedly never met in person. Both went on to found major aluminum companies—Héroult in Europe and Hall with the company that became Alcoa in the United States—and their parallel careers are a celebrated case in the history of science.