Interestingly, aluminum is the third most abundant element on the earth’s surface (oxygen and silicon being more common). It is the most abundant of all the metals.  Because it is rather reactive, it is not found in nature in the free state.  However, its compounds are very common.  It occurs as aluminum oxide in the minerals corundum and bauxite.

Hall worked in a woodshed using homemade and borrowed equipment.  After about a year he found that aluminum oxide dissolves in molten cryolite to produce a solution from which aluminum can be made under electrolysis.  (Cryolite is a rare mineral found in appreciable quantities only in Greenland.  It is presently synthesized in large quantities to meet today’s needs.)  Hall’s discovery was important since the melting point of aluminum oxide alone is 2050 degrees Celsius - much too high for convenient handling.  The cryolite-alumina mixture melts at 1000 degrees.  Hall passed an electric current through this solution to produce aluminum.  Hall used an iron frying pan as a container for the cryolite-alumina mixture which he melted over a blacksmith's forge.  The electric current came from electrochemical cells that he made from jars that his mother used to can fruit.

By an odd coincidence Paul Heroult, who was the same age as Hall, made the same discovery independently in France about the same time.  As a result of the discovery of Hall and Heroult, the large-scale production of aluminum became economically feasible for the first time, and it became a common metal.

As his professor had predicted, Hall died a wealthy man.  Today the company that was founded to produce aluminum by Hall’s process - the Aluminum Company of America (Alcoa) - is worth billions of dollars.  A life-size aluminum sculpture of Hall stands in the science building of Oberlin College.

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