Paul Héroult was a French scientist. He was the inventor of the aluminium electrolysis and developed the first successful commercial electric arc furnace.
Paul-Louis-Toussaint Héroult, French chemist who invented the electric-arc furnace—widely used in making steel—and, independently of the simultaneous work of Charles M. Hall of the United States, devised the electrolytic process for preparing aluminum. This process made low-priced aluminum available for the first time, securing the widespread use of the metal and its alloys.

While a student at the École des Mines, Paris, Héroult began working on the electrolysis of aluminum compounds. In 1886 he found that electrolysis of a solution of alumina (aluminum oxide) in molten cryolite (sodium aluminum fluoride) resulted in the formation of a layer of molten aluminum at the bottom of the vessel. The Héroult process is essentially identical to the one discovered by Hall in the same year. After prolonged patent litigation, an agreement was reached between the two inventors.

Héroult is also noted for the Héroult electric furnace named for him, which found widespread use in the manufacture of aluminum and ferroalloys, first in Europe and later throughout the world.
When he was 15 years old, the aluminium was as expensive as silver and was used mostly for luxury items and jewellery. Héroult wanted to make it cheaper. He succeeded in doing so when he discovered the electrolytic aluminium process in 1886.[2] The same year, in the United States, Charles Martin Hall (1863–1914) was discovering the same process. Because of this, the process was called the Hall–Heroult process.

Héroult’s second most important contribution is the first commercially successful electric arc furnace (EAF) for steel in 1900. In 1905, Paul Héroult was invited to the United States as a technical adviser to several companies, and in particular to the United States Steel Corporation and the Halcomb Steel Company. Halcomb installed the first Héroult furnace in the US. This process gradually adopted in all smelters through out world.