Charles Martin Hall was born on December 6, 1863, and died on December 27, 1914. He was an American inventor, businessman, and chemist. He is most famous for creating a low-cost method to make aluminum in 1886. This method made aluminum the first metal to be widely used after iron was discovered long ago. Hall was one of the founders of Alcoa. Other founders included Alfred E. Hunt, who worked with George Hubbard Clapp at the Pittsburgh Testing Laboratory, W. S. Sample, who was Hunt’s chief chemist, Howard Lash, who led the Carbon Steel Company, Millard Hunsiker, who managed sales for the Carbon Steel Company, and Robert Scott, a mill supervisor for the Carnegie Steel Company. Together, they collected $20,000 to start the Pittsburgh Reduction Company. This company later became known as the Aluminum Company of America and was eventually shortened to Alcoa.

Biography

Charles Martin Hall was born on December 6, 1863, in Thompson, Ohio, to Herman Bassett Hall and Sophronia H. Brooks. His father, Herman, graduated from Oberlin College in 1847 and studied at Oberlin Theological Seminary for three years, where he met his future wife, Sophronia Brooks. They married in 1849 and spent the next ten years working as missionaries in Jamaica, where five of their eight children were born. They returned to Ohio in 1860 after foreign missions were closed due to the Civil War. Charles had two brothers and five sisters; one brother died before reaching his first birthday. One of his sisters, Julia Brainerd Hall (1859–1925), was a chemist who helped him with his research.

Hall began learning at home, and his mother taught him to read at an early age. By age six, he was reading his father’s 1840s chemistry book. At age eight, he entered public school and advanced quickly.

In 1873, Hall’s family moved to Oberlin, Ohio. He studied for three years at Oberlin High School and one year at Oberlin Academy to prepare for college. During this time, he showed an interest in chemistry and invention, conducting experiments in his home’s kitchen and woodshed. In 1880, at age 16, he enrolled at Oberlin College.

During his second year, Hall attended a lecture by Professor Frank Fanning Jewett on aluminum. Jewett showed a sample of aluminum obtained from Friedrich Wöhler and said, “If someone could find a way to make aluminum on a large scale, they would help the world and gain great wealth.”

Hall began experimenting with aluminum in 1881. He tried to make aluminum from clay using carbon and potassium chlorate but failed. He then studied cheaper ways to produce aluminum chloride, also without success. In his senior year, he tried to electrolyze aluminum fluoride in water but could not produce aluminum.

In 1884, Hall built a homemade coal-fired furnace and bellows in a shed behind his family home. He tested mixtures of alumina and carbon with barium salts, cryolite, and sodium carbonate to find a way to produce aluminum. He also tried using sodium to reduce cryolite but got poor results. He made aluminum sulfide but found it unsuitable for producing aluminum.

Hall made most of his equipment and prepared his chemicals, with help from his sister Julia. On February 23, 1886, he discovered a method to produce aluminum by passing electricity through a mixture of alumina and cryolite, creating a pool of liquid aluminum. On July 9, 1886, Hall filed his first patent for this process. Around the same time, the French scientist Paul Héroult discovered the same method, and it became known as the Hall–Héroult process.

After failing to find financial support in the United States, Hall traveled to Pittsburgh, where he met metallurgist Alfred E. Hunt. Together, they formed the Reduction Company of Pittsburgh, which built the first large-scale aluminum production plants. The company later became the Aluminum Company of America, then Alcoa. Hall was a major owner and became wealthy.

The Hall–Héroult process reduced the cost of aluminum by 200 times, making it widely usable. By 1900, about 8,000 short tons (7.3 million kilograms) of aluminum were produced annually. As of 2022, more aluminum is produced yearly than all other non-ferrous metals combined.

Hall is sometimes linked to the American spelling of “aluminum,” but this spelling was briefly used by Humphry Davy in the early 1800s and appeared in Noah Webster’s Dictionary of 1828. “Aluminium” was common in the United States until the early 1900s, and the American Chemical Society officially adopted “aluminum” in 1925. Hall’s early patents used “aluminium.” In the United Kingdom and other countries using British spelling, only “aluminium” is used today. Most other languages use a form ending in “-ium.”

Hall continued researching aluminum production and was granted 22 U.S. patents. He served on the Oberlin College Board of Trustees and influenced business decisions at Alcoa until his death.

Hall died unmarried and without children on December 27, 1914, in Daytona, Florida, 21 days after turning 51. He was buried in Westwood Cemetery in Oberlin. Hall and Héroult were born and died in the same years.

In his will, Hall donated most of his wealth to charity. His donations helped create the Harvard–Yenching Institute, a foundation that supports higher education in Asia.

Awards and honors

Hall was elected to the American Philosophical Society in 1898. In 1911, he received the Perkin Medal, which is the highest honor given by the American section of the Society of Chemical Industry. In 1997, the method for producing aluminum through electrochemistry, which Hall discovered, was named a National Historic Chemical Landmark by the American Chemical Society.

Hall later became one of Oberlin College’s most important supporters. A statue made of aluminum was placed on the college campus. Because aluminum is very light, the statue was often moved from place to place, sometimes because students played jokes on it. Now, the statue is attached to a large block of granite and remains in a fixed location on the second floor of Oberlin’s science center. Students still decorate the statue with holiday-themed items on special occasions.

The Jewett home in Oberlin is preserved as the Oberlin Heritage Center. The center includes an exhibit titled Aluminum: The Oberlin Connection, which shows a recreated version of Hall’s 1886 woodshed experiment. The Hall House is also preserved in Oberlin, though the original woodshed was removed many years ago.

Patents

• US Patent 400,664, A method for removing aluminum from fluoride compounds using electricity — C. M. Hall, applied in 1886, granted in 1889. TIFF Image of page from USPTO.