Aluminum's Strange Journey From Precious Metal To Beer Can
Aluminum's Strange Journey From Precious Metal To Beer Can
Aluminum ingots sit stacked in a warehouse at the Port of New Orleans last year.
Aluminum is used everywhere from soda to space capsules, but that hasn't always been the case.
Short Wave is celebrating the 150th anniversary of the periodic table with profiles of some of its favorite elements. Here are a few things you may not have known about aluminum.
Aluminum is the most abundant metal on Earth, and one of the cheapest to buy. But it used to be more valuable than gold.
Aluminum is the third most common element in the Earth's crust, but it also bonds easily with other elements. That means it is not found in nature as a pure metal.
For decades after it was first identified by British chemist Sir Humphry Davy in the early 1800s, scientists and tinkerers tried, and mostly failed, to find a good method for separating aluminum from everything else that stuck to it.
France's Emperor Napoleon III was an early proponent of aluminum. He hoped the lightweight metal could be used to produce weapons and armor, giving his soldiers an edge in battle. The emperor funded the work of Henri Sainte-Claire Deville, who found a chemical method for obtaining pure aluminum, but it was still a slow process. An often repeated story goes that Napoleon III, frustrated with progress on aluminum, had much of France's stock melted down and turned into cutlery. He and his honored guests used aluminum utensils, while everyone else at the imperial dinner table made do with gold.
The aluminum tip is placed atop the Washington Monument on Dec. 6, 1884, as shown in a contemporary illustration.
In 1884, when the Washington Monument was completed, it was capped with a large casting of aluminum. The capping ceremony and the dedication of the monument "were given front-page publicity in the nation's newspapers and the aluminum point or apex was creditably described," according to a 1995 article published in the journal of the Minerals, Metals & Materials Society. "Hundreds of thousands, perhaps millions, of people who had never before even heard about aluminum now knew what it was."
At the time, a pound of aluminum was worth $16 ($419 in today's dollars).
Two years later, a commercially viable method for extracting aluminum from ore was discovered, and by 1889 the price had fallen to $2 per pound. Within 10 years of commercial refining, it plummeted to just 50 cents a pound.
The modern method of obtaining aluminum was discovered simultaneously by two young scientists working independently on different continents.
In 1886, two men, both 22 years of age — one working in Ohio and the other in northwestern France — developed the modern method for producing aluminum metal.
American Charles Martin Hall went to work after being inspired by a lecture at Oberlin College in which his chemistry professor pronounced that the discoverer of a practical way to produce aluminum "will bless humanity and make a fortune for himself."
Frenchman Paul Héroult was working on the same problem.
At nearly the same time, the two men hit upon the same answer: electricity, and lots of it.
Still used today, this is how their method works: Alumina from bauxite is dissolved in another mineral, cryolite, at 1,832 degrees Fahrenheit. The molten mixture is poured into a specially designed vat, and vast amounts of electricity are passed through it. The process causes aluminum metal to condense at the bottom of the vat.
The two men fought over ownership of the process they developed to smelt aluminum from bauxite ore. Héroult filed for his patent six weeks before Hall, but the American was able to prove (thanks to the meticulous laboratory notes kept by his sister and assistant, Julia Brainerd Hall) that he had actually made the discovery a few weeks before his rival. Ultimately, the two men settled their dispute and became friends.
In 1888, Hall co-founded the Pittsburgh Reduction Co. to produce aluminum. The company later became the aluminum giant Alcoa. The following year, Héroult scaled up the process in France.
The two men died the same year, in 1914, both age 51.
The development of the Hall-Héroult process, as it came to be known, was a major milestone in the Industrial Revolution. But it has also carried an environmental cost: The electricity needed produces large quantities of greenhouse gases. Aluminum production alone is responsible for about 1% of global emissions, according to estimates.
The availability of aluminum at the turn of the 20th century spurred on the age of flight and the Space Age.
Orville Wright, lying at the controls on the lower wing, pilots the Wright Flyer on the first powered flight by a heavier-than-air aircraft, on Dec. 17, 1903, at Kitty Hawk, N.C.
In 1903, Wilbur and Orville Wright were struggling with the design of their Wright Flyer, the one that would go on to make history.
"There was no question that they knew they needed something that was light, otherwise the thrust-to-mass ratio wouldn't be high enough," says Donald Sadoway, a professor of materials chemistry at the Massachusetts Institute of Technology.
It was Charles Taylor, the Wrights' "mechanician" collaborator, who first suggested using an alloy of aluminum and copper for the block of their crude four-cylinder gasoline engine. It was a novel idea to reduce their airplane's overall weight.
"It was a very marginal airplane at best," says Robert van der Linden, a supervisory curator at the Smithsonian National Air and Space Museum. "So it needed every ounce of strength and every ounce of weight saved to get that thing in the air."
The 180-pound engine — 20 pounds lighter than designed, thanks to the aluminum — exceeded expectations and let the Wright Flyer take off.
Although the rest of the plane was wood and fabric, by the end of the 1920s, ever-faster planes made aluminum an obvious choice for the fuselage, too.
"Until then, biplanes covered in fabric were just fine," van der Linden says. "But if you get faster than about 150 miles per hour ... you need a stronger material."
Again, aluminum was key. It became the dominant metal in aviation.
Recycling it was cheaper and less time-consuming than refining it from ore. So during World War II, Americans were encouraged to turn in their aluminum cooking pots and even aluminum foil from gum wrappers and cigarette packs, to help with the war effort.
NASA also turned to aluminum alloys for Apollo for the same reason that they had been so indispensable for airplanes — weight and strength.
The next-generation Orion capsule is lifted to be mated to a test stand for pressure checks inside, at Kennedy Space Center in Florida.
The next-generation Orion space capsule is being made mostly out of an aluminum-lithium alloy.
When it comes to spaceflight, "weight is everything," van der Linden says. "Aluminum alloys are perfect for that."
Where would modern aviation and spaceflight be without aluminum?
"I don't see it happening because there's really no other metal or any other material out there that could do what aluminum alloys have done," he says.
The aluminum beverage can was introduced in 1959
Beer-maker Coors was the first to use the aluminum drink can.
Before then, "the packaging in primary use for pretty much all beverages was steel cans and bottles," says Heidi Harris, Coors' archivist.
"Steel cans with beer in particular didn't work well," she says. The steel, Harris says, left a funny taste.
But there was another consideration. Bill Coors, the company's CEO at the time, was not happy seeing the steel cans "littering everywhere," Harris says.
"He wanted to come up with a can that consumers could one, recycle, and two, would still keep the beer in good flavor for longer periods of time," she says.
At first, cold beer in aluminum cans got a lukewarm reception. However, by the mid-1960s, the new can had really started to catch on, even among Coors' competitors.
Atlanta-based Novelis, which is today the largest producer of sheet aluminum for cans, says more than 60% of the aluminum it produces is recycled — and most of that comes from and goes back into cans. To recycle aluminum takes only about 5% of the energy used to produce new metal, says Todd Summe, the chief research and development officer at Novelis.
That means the carbon footprint from a beer or soda can is smaller than it would be if the aluminum came fresh from the earth.
"The beverage can made of aluminum is the most recyclable [and] most sustainable package, and it is being infinitely recycled," Summe says.
Is it aluminum or aluminium?
Davy, the element's discoverer, gets a large share of the blame for all this confusion over the U.S. and British spellings and pronunciation of the word.
At first, he called his new element "alumium," but despite having previously discovered three other elements that he gave the "-ium" suffix to (potassium, sodium and magnesium), he inexplicably changed to "aluminum" in his 1812 book, Elements of Chemical Philosophy.
Other scientists of the day seemed to prefer "aluminium," and that's the spelling and pronunciation used today by the British.
America went with Davy's "aluminum." It was listed as the preferred spelling in The Century Dictionary (published in New York) in 1889 and as the only spelling in the Webster Unabridged Dictionary of 1913.
The American Chemical Society initially sided with the scientific community and called it "aluminium." But by 1925, with the lightweight metal's uses on the rise in the U.S., the society relented and switched to "aluminum."
MMW
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