When aluminum was first introduced to the public at the Paris Exposition of 1855, a writer for National Magazine remarked, “just now, in this new metal, so long concealed in every hill-side, and even in the very dust of our streets, science seems about to make over to the arts one of her occasional bestowments, by which both the knowledge and power of our race are, at an instant, so widely increased.”
The American Chemical Society designated the Commercialization of the Hall Aluminum Process a National Historic Chemical Landmark in Pittsburgh, Pennsylvania, on November 2, 2001.
Aluminum, the third most abundant element in the earth’s crust — and its most plentiful metal — is made from bauxite, a reddish-brown rock discovered in Les Baux, France, in 1821. But it wasn’t until 1886 that chemists finally discovered an economical way to separate pure aluminum from its ore. Two years later, on Thanksgiving Day, a pilot plant in Pittsburgh introduced the first commercial aluminum.
As predicted, the commercialization of this light, lustrous and non-rusting metal has revolutionized the world. Today, aluminum is used to make everything from aircraft to art, buildings, power lines and packaging.
More than 7,000 years ago, Persians made their strongest pottery out of clay containing aluminum oxide. Three millennia later, ancient Egyptians were using other aluminum compounds in medicines, dyes and cosmetics. But because aluminum has a high affinity for oxygen and never occurs in its metallic form in nature, it proved difficult to isolate. In 1808, Sir Humphry Davy gave aluminum its name. In 1825, the Danish chemist Hans Christian Oersted finally produced a sample — albeit very impure — using heat and a potassium-based mixture. Over the next 20 years, Friedrich Wöhler, a German chemist, improved this process by using metallic potassium.
Henri Sainte-Claire Deville of France substituted potassium with less expensive sodium in 1854 and was able to create enough aluminum for display at the Paris Exposition of 1855. Billed as “silver from clay,” aluminum bars were shown alongside France’s crown jewels. The juxtaposition was fitting: rubies, emeralds and sapphires consist mainly of crystalline aluminum oxide.
At that time, pure aluminum was valued at $115 per pound — more expensive than gold. Napoleon III proudly displayed aluminum cutlery at his state banquets, commissioned aluminum equipment for his military and even had an aluminum and gold baby rattle made for his son.
In 1886, Charles Martin Hall of the United States and Paul L.T. Héroult of France — both age 22 — independently discovered the way to produce aluminum economically. Hall, under the initial direction of his Oberlin College professor, Frank Fanning Jewett, developed a method for “reducing” aluminum oxide, called alumina, to pure aluminum by electrolysis. In the electrolytic cell, alumina is dissolved in molten cryolite. A strong electric current passes through the solution and removes the oxygen, leaving deposits of nearly pure aluminum on the bottom of the bath. These deposits are siphoned off and cast into pigs. This method is still used today.
“Production of Aluminum Metal by Electrochemistry” Landmarks site, from The Challenge through Simultaneous Discoveries
A group of six industrialists led by Alfred E. Hunt provided the financial backing that enabled Hall to found the Pittsburgh Reduction Company in 1888. Before that year was out, Hall and his first employee, Arthur Vining Davis, had produced the first commercial aluminum.
As Hall improved his process, the price of aluminum ingots dropped from $4.86 per pound in 1888 to 78 cents per pound in 1893. Because manufacturers were reluctant to use an unfamiliar metal, the company developed prototype products such as the first cast aluminum tea kettle for use as sales tools.
In 1907, the company was renamed the Aluminum Company of America (Alcoa). Business grew as manufacturers grasped the benefits of this light yet strong metal. In the mid-1930s, industrial designer Henry Dreyfuss predicted that “aluminum will play a large and significant part” in the “greatest period of redesign the world has known.” By the late 1930s, a pound of aluminum cost just 20 cents; its uses numbered more than 2,000.
Aluminum was at the forefront of the development of our industrial society and also played a strategic role in World War II. Demand doubled as the material spawned a new generation of aircraft and automobiles. Aluminum products also included cooking utensils, foil, electric wire and cable.
Today, the United States is the world’s greatest producer and consumer of aluminum — metal of the modern era. The process begins with truckloads of dirt and ends with billions of recycled items.
Mining bauxite Four tons of bauxite produce one ton of aluminum — enough to make the cans for more than 60,000 soft drinks. Bauxite is formed over millions of years by chemical weathering of rocks containing aluminum silicates, producing an ore rich in aluminum oxide. Today, bauxite is mined primarily in Africa, Australia and the Caribbean.
Refining alumina The ore is ground and mixed with lime and caustic soda, then heated in high-pressure containers. The aluminum oxide is dissolved by the caustic soda, precipitated out of the solution, washed and heated to eliminate water. The resulting alumina is a white powder resembling sugar.
Smelting into aluminum An electrolytic reduction process known as smelting dissolves the alumina in a cryolite bath inside carbon-lined cells, or pots. A powerful electric current, which is passed through the bath, separates aluminum metal from the chemical solution and the metal is siphoned off. Smelting is the industrial-scale version of the process developed in 1886 by Charles Martin Hall in his woodshed laboratory.
Fabricating products Aluminum goes from the smelting pot into the furnace for mixing with other metals. These alloys have specific properties to meet specific uses. Fluxing purifies the metal, which is then poured into molds or cast into ingots. Fabrication may include forging, casting, rolling, drawing or extruding to create different finished products from automobiles to aircraft. Recycling extends the life cycle of aluminum products, the most valuable material in the waste stream.
In contact with air, aluminum rapidly becomes covered with a tough, transparent layer of aluminum oxide — second only in hardness to a diamond — that resists further corrosion and does not tarnish or rust. “Eros,” an aluminum statue designed by Sir Alfred Gilbert and first erected in 1893, has stood in Piccadilly Circus unaffected by the elements for more than 100 years.
From furniture to fashion, artists embrace aluminum in their crafts. Musical instrument makers, recognizing superior acoustic properties, use the metal for sound boards and violin and piano strings. Austrian architect Otto Wagner was among the first to use aluminum to accent modern buildings such as Die Zeit (1903) and Postal Savings Bank (1904-06).
More than 90 percent of the power lines in the United States are made of aluminum. In 1884, a 100-ounce cast aluminum pyramid was placed atop the Washington monument as a lightning conductor. Also an excellent conductor of heat, the metal is used in automobile radiators, cooling coils and heat fins in baseboard and other heaters.
Transportation is the largest sector of the aluminum market, as composites replace heavier metals in fuel-efficient cars and trucks. The Wright Brothers made the engine block of their 1903 flyer out of aluminum. Union Pacific Railroad launched the first all-aluminum, high-speed train in 1934.
Aluminum alloys often replace steel, wood and other materials in structures such as the Empire State Building. Pure aluminum is weaker than steel, but aluminum combined with other elements can provide equal strength while weighing 35 to 80 percent less.
More than 20 percent of the aluminum manufactured goes into packaging and is continually reengineered to enhance products. The ubiquitous aluminum can is more than 50 percent lighter than it was 20 years ago. About 100 billion aluminum beverage cans are produced annually in the United States —99 percent of all beer cans and 97 percent of all soft drink cans. More than half of each can is made from recycled aluminum, the most reused of all packaging materials.
The first all–aluminum beverage can appeared in 1963 and the first recycling effort began in California in 1968. In 2000, the recycling rate for aluminum cans was more than 60 percent, compared with only 15.4 percent in 1974.
Today, more than 10,000 aluminum recycling centers operate across the United States. Recycled aluminum —from packaging to approximately 90 percent of automotive aluminum scrap — makes up one-third of America’s aluminum supply. Recycling saves almost 95 percent of the energy needed to produce aluminum from its ore — conserving natural resources and reducing pollutants such as carbon dioxide, nitrous oxides and sulfur dioxide while also reducing the need for solid waste disposal.
In 1996, recycling saved the equivalent of more than 18.4 billion barrels of oil, or 10.8 billion kilowatt hours — enough energy to supply electricity to a city the size of Pittsburgh for about six years.
Charles Martin Hall would have been proud that the process he discovered, and its commercialization, would also create valuable recycled materials.
Charles Martin Hall: Aluminum’s ‘Boy Wonder’
At age 12, Charles Martin Hall began experimenting with minerals, turning a small woodshed behind his home into a makeshift laboratory. He first studied chemistry using an 1840s textbook from the shelves of his minister father’s study. By age 16, he was a freshman at Oberlin College, venturing into the chemistry lab to borrow items he needed for his lab at home. His chemistry professor, Frank Fanning Jewett, showed students a small bit of aluminum and said the person who discovered an economical way to produce the metal would become rich. Hall leapt at the challenge. Hall was born in Thompson, Ohio, in 1863. He graduated from college in 1885 and went back to his woodshed to work on the purification of aluminum. His concept was to find a nonaqueous solvent for aluminum oxide, in order to produce metallic aluminum by electrolysis using carbon electrodes. On February 23, 1886, Hall found the solvent he needed: molten cryolite, the mineral sodium aluminum fluoride. He produced his first small bits of aluminum using the cryolite, aluminum oxide and homemade batteries.
Hall founded the Pittsburgh Reduction Company, and in 1888, began production of pure aluminum on a commercial scale. In 1907, the company became the Aluminum Corporation of America (Alcoa). He spent the next 25 years perfecting his process and developing the aluminum industry.
In 1911, Hall was awarded the Perkin Medal for his accomplishments. He died in Daytona Beach, Florida in 1914.
Every minute of every day, an average of more than 123,000 aluminum cans are recycled.
Since 1972, an estimated 660-plus billion beverage cans have been recycled — placed end-to-end, they could stretch to the moon nearly 300 times.
The average lifespan of an aluminum beverage can is six weeks, including the time it takes to be manufactured, filled, sold, recycled and remanufactured.
Recycling one aluminum can saves enough energy to keep a 100-watt bulb burning for almost four hours or provide enough power to a television for three hours.
Tossing an aluminum can wastes as much energy as pouring out half of that can’s volume of gasoline. If each person recycles one aluminum can each month, energy savings equal 1,750 to 3,500 gallons of gas.
American consumers and industry throw away enough aluminum to rebuild the entire U.S. commercial air fleet every three months. Aluminum made up 1.5 percent of the total municipal solid waste stream in the United States in 1994. The overall rate for aluminum packaging was 55 percent.
In 1884, total United States aluminum production was 125 pounds. That year, a 100-ounce cast aluminum pyramid paced atop the Washington Monument represented twenty percent of this production.
Four tons of bauxite produces one ton of aluminum — enough to manufacture 60,000 beverage cans or space frames for seven full-size cars or 40,000 computer memory disks.
One pound of aluminum can replace twice that weight in steel in most applications.
Rubies, emeralds and sapphires consist mainly of crystalline aluminum oxide.
Manufacturers used Cold War technology to make Little League bats from aluminum.
Aluminum is light, strong, corrosion-resistant, nonmagnetic, nontoxic and naturally good looking.
Aluminum Association, Inc. http://www.aluminum.org/
Information about aluminum musical instruments http://www.mugwumps.com/aluminum.htm
The American Chemical Society designated the production of aluminum by electrochemistry in Oberlin, Ohio, a National Historic Chemical Landmark on September 17, 1997. The plaque commemorating the event reads:
“On February 23, 1886, in his woodshed laboratory at the family home on East College Street, Charles Martin Hall succeeded in producing aluminum metal by passing an electric current through a solution of aluminum oxide in molten cryolite. Aluminum was a semiprecious metal before Hall’s discovery of this economical method to release it from its ore. His invention, which made this light, lustrous, and nonrusting metal readily available, was the basis of the aluminum industry in North America.”
The American Chemical Society designated the commercialization of the Hall aluminum process in Pittsburgh, Pennsylvania, a National Historic Chemical Landmark on November 2, 2001. The plaque commemorating the event reads:
“In 1886 Charles Martin Hall invented an economical electrochemical process to release aluminum from its ore. Until then, this light, lustrous and non-rusting metal was rare and costly. A group of Pittsburgh investors, headed by metallurgist Alfred E. Hunt, agreed to support the commercialization of Hall's process and founded the Pittsburgh Reduction Company. In 1888 Hall, assisted by Arthur Vining Davis, began to produce aluminum in the company's pilot plant on Smallman Street. In 1907 the company became the Aluminum Company of America (Alcoa). Aluminum has since become part of everyday life with many uses — from teakettles in the early days, to aircraft, power lines, building materials, food packaging, and artwork.”
Log In