Charles Martin Hall pictured at the right was an American chemist, who discovered an inexpensive method for the isolation of pure aluminium from its compounds. The same electrolytic process was discovered concurrently by the French chemist Paul L.T. Heroult and is therefore known as the Hall-Heroult process. It became the basis for the aluminium industries both in the United States and in Europe.
Hall was born in Thompson, Ohio, on December
6th 1863. He became interested in chemistry, and more specifically
in finding an inexpensive method for producing aluminium.
While an undergraduate at Oberlin College. After his graduation in 1885,
Hall set up laboratory at
home and began work on the purification of aluminium. He had the
idea that if he could find a non-aqueous solvent for aluminium oxide, he could
produce metallic aluminium by electrolysis, using carbon electrodes. On Feb.
23, 1886, Hall found that molten cryolite, which is the mineral sodium aluminium
fluoride, was the solvent he needed for the process; using the cryolite and
aluminium oxide and homemade batteries, he produced his first small globules
of aluminium. (Hall's experimental work)
(Hall's experimental work)
Hall had trouble-finding backers for his
process. Eventually he went to Pittsburgh, where a small group formed the
Pittsburgh Reduction Company, which grew to be the first largest producer of
aluminium in the United States. This company later became the Aluminium Company
Hall spent the rest of his life
developing both his process and the aluminium industry. In 1911 he was awarded
the Perkin Medal for his work. Hall died a very rich man in Daytona Beach, Fla.,
on Dec. 27, 1914 aged just 51.
This is a picture of what a Hall cell looks like. It clearly shows the conditions necessary for the electrolysis to occur.
The aluminium ions receive electrons to become atoms again:
This is a reduction reaction since electrons are gained.
The oxide ions lose electrons to become oxygen molecules, O2:
This is an oxidation reaction since electrons are removed..