Drawing of the original Hall electrolytic cell set-up in the Pittsburgh Reduction Company plant, which shows the cast-iron crucibles, or "pots"; the carbon anodes suspended by copper rods from an overhead copper support; and, on the floor, ingot molds.
Courtesy Alcoa Inc.
Discovered in 1827 by Friedrich Wöhler, aluminum, though the most common metal on earth, is always found tightly locked in compounds. Efforts to use electrolysis to reduce it failed repeatedly, and for years it remained an exotic metal used in jewelry and for such special purposes as capping the Washington Monument.
Paul Héroult.
Courtesy Alcoa Inc.
The race for a commercially viable route to aluminum was won in 1886 by two young men working independently—Paul Héroult (1863–1914) in France and Charles M. Hall (1863–1914) in the United States. Hall was just six months out of Oberlin College; his sister Julia (1859–1925), who had also been a chemistry major at Oberlin, was of great assistance to him—helping with experiments, taking laboratory notes, and giving business advice.
Julia Brainerd Hall, Charles's sister, who made many contributions to the discovery of the electrolytic means of producing aluminum and to the business success of the Pittsburgh Reduction Company and the Aluminum Company of America.
Courtesy Alcoa Inc.
The problem many researchers had with extracting aluminum was that electrolysis of an aluminum salt dissolved in water yields aluminum hydroxide. Both Hall and Héroult avoided this problem by dissolving aluminum oxide in a new solvent-fused cryolite, Na3AlF6. To scale up the process took Hall years of development and capital investment. In 1888 he joined with Alfred E. Hunt, an experienced metallurgist, to form the Pittsburgh Reduction Company. After exhausting the initial investment, the fledgling company was buoyed by the resources of the Mellon banking interests.
Charles M. Hall at the age of 22.
Courtesy Alcoa Inc.
Almost immediately the price of aluminum dropped dramatically. Developments in the early 1880s had reduced the price of a pound of aluminum from 12 dollars to 4 dollars a pound. The Hall process reduced it to 2 dollars a pound, and shortly after the company’s move to Niagara Falls—the first electrochemical company in that location—to 75 cents and then 30 cents. In 1907 the company was renamed the Aluminum Company of America, and in the 1990s this name was shortened to Alcoa Inc.