One of the scientists who independently worked on this process was Paul Heroult, who is a French scientist born on April 10, 1863. He was the inventor of the aluminum electrolysis and developed the first successful commercial electric arc …show more content…
Hall continued his research and development for the rest of his life and was granted 22 US patents, most on aluminum production. Hall became one of Oberlin College 's most prominent benefactors, and an aluminum statue of him exists on the …show more content…
The problem with extracting aluminum was that electrolysis of an aluminum salt dissolved in water which creates aluminum hydroxide. Elemental aluminum cannot be produced by the electrolysis of an aqueous aluminum salt. Both Hall and Heroult avoided this problem by dissolving aluminum oxide in a new solvent-fused cryolite. Aluminum oxide has a melting point of 2,000 C, so electrolysis is impractical, however pure cryolite has a melting point of 1,012 C. Thus with a small percentage of alumina dissolved in it and its melting point drops to about 1,000 C. Then passing a low voltage through it which causes liquid aluminum metal. Then aluminum fluoride is added to the mixture to reduce the melting point. To scale up this process it took Hall years of development and capital investment; in 1888 he joins with Alfred E. Hunt who was an experienced metallurgist, to form the Pittsburgh Reduction company. However, after exhausting the initial investment the company was buoyed by the resources of the Mellon banking interests. In today 's society, there are two primary technologies using the Hall-Heroult process which are Soderberg and prebake. The one that is more efficient is prebake, but it is more labor intensive; prebake is becoming more preferred in the industry because of the various pollutant emissions related