Formal Sciences & Matter / Chemistry & Materials

Hall-Héroult Process (Aluminium)

Hall and Héroult independently find (1886) how to win aluminium by electrolysis; a once-precious metal becomes an everyday material.

Aluminium is abundant in clay, but chemical methods made it extremely costly in the 19th century. In 1886 Charles Martin Hall in Ohio and Paul Héroult in France discovered that alumina dissolved in molten cryolite can be split with strong electric current, which dynamos had just made cheap. Light, strong and rustproof aluminium went into cables, cookware, aircraft and cans; the world now produces around 70 million tonnes of primary metal a year.