Aluminum is found in a vast range of products, from soda cans to car components. Yet, not many people know what aluminum is made of or how it's made. Although aluminum is found abundantly in the earth's crust in the mineral cryolite and the rock bauxite, you won't find it in pure form in everyday products.
Aluminum is made of other elements because it does not naturally occur in pure form. It needs to undergo chemical processes before it can be turned into standard products like foil and food packaging.
Aluminum production has a long history, dating back to ancient times when an aluminum-based salt called Alum was used for its fire-resistant properties in the leather and paper industries. However, it was not until the 19th century that aluminum, as we know it today, was discovered.
In 1808, English chemist Humphry Davy theorized that aluminum could be produced by electrolytically reducing alumina or aluminum oxide, but lacked the necessary equipment to test his idea. It wasn't until 1825 when Hans Christian Oersted created an aluminum alloy based on Davy's ideas.
German chemist Friedrich Woehler furthered Oersted's work and produced the first small mounds of solidified molten aluminum in 1845. Henri-Etienne Sainte-Claire Deville then utilized chemical methods to create industrial aluminum and produced it in France in 1856. Initially, it was an expensive luxury metal, similar to silver and used for making medals.
Under Napoleon III's leadership, aluminum production in France received significant backing, leading to an exciting future for the metal. Today, aluminum is widely used in various industries due to its unique properties, including its lightweight and corrosion resistance.
Two individuals, Paul Heroult and Charles Hall, redefined the aluminum creation process in 1886. The engineer and student recognized the reduction of molten aluminum oxide in cryolite was effective for making aluminum using electric power. The Hall-Heroult process is a primary way of making aluminum in the 21st century.
Another method for producing aluminum was discovered by Karl Josef Bayer in 1888. The Bayer process involves heating bauxite and an alkali mixture to create aluminum.
In general, the aluminum-making process involves three steps: mining for bauxite, extracting alumina from the mined bauxite and turning the alumina into aluminum. In this guide, we'll look at each step of the aluminum production process from the mine to the shelves to show you how it's made.
Aluminum is not found in its pure form in nature and needs to be extracted from bauxite. Bauxite is a type of sedimentary rock featuring traces of aluminum. This rock is the world's main source of aluminum, and experts must refine the sedimentary rock to create alumina. Most countries have bauxite deep below the earth's surface, but the material is more abundant in tropical zones. Aside from Africa and South America, China, India and Indonesia are top providers of bauxite rock. Bauxite is primarily used in the aluminum-making industry, but there is a place for the sedimentary rock in the adhesive, cement and chemical fields as well.
The process of mining aluminum involves extracting bauxite ore, refining it to produce alumina, and then smelting the alumina to extract pure aluminum. The extracted aluminum can then be used to manufacture a wide range of products, from aircraft parts to cans.
Bauxite rock is mined and extracted through land clearing, digging, and removing thick sections of bauxite ore by means of blasting or ripping. Bauxite mining calls for the use of heavy equipment. Miners commonly use machines like bulldozers, scrapers, front-end loaders, and hydraulic excavators to help with the digging. Areas rich with bauxite can be restored once the aluminum mining process is complete.
Bauxite is typically found near the surface and extracted from the earth via open-pit mining or strip mining techniques. Both of these mining methods involve removing the soil and rocks covering the layer of bauxite.
Mining starts with the removal of trees and vegetation. The topsoil is then removed and stored for the post-mining restoration process. In most forested areas where bauxite mining takes place, the land returns to its original ecosystem. This is made possible through mine rehabilitation practices that include leveling the land and replacing the topsoil that was displaced.
Miners must make sure the aluminum production cycle does not interfere with animal and plant life in mining locations. Therefore, red mud is removed from mining areas to prevent harmful pollution to the environment.
Once miners reach the layer of bauxite, they might use drilling or blasting methods to break the bauxite into loose pieces. The bauxite pieces are then usually loaded into a truck or other vehicle and transported to a plant for crushing and sorting.
Bauxite aluminum can be transported in shipping containers by truck, rail, or ship. Below is a breakdown of each of the common methods of bauxite transportation.
Some forms of bauxite require miners to clean and dry the materials before shipping them to refineries. In these scenarios, clay is removed from the bauxite and the materials are placed into kilns. Most alumina refineries are located near the mines to streamline transportation.
Although bauxite has various applications, about 85 percent of bauxite production is used to manufacture alumina. As the demand for quality aluminum products continues to grow, so will the need for bauxite mining. It's estimated that the current bauxite reserves will last for centuries.
Related: Top 10 Aluminum Producing Countries
The second step in aluminum production is alumina refining. To separate alumina from bauxite, the sedimentary rock is exposed to caustic soda at extreme temperatures. Alumina can be removed from bauxite, but the process requires the use of precipitator tanks in a refining facility.
Alumina is the name given to aluminum oxide, which is a white, odorless powder. Alumina is used in many different industries. For example, it's applied in metallic paint manufacturing as well as the production of spark plug insulations.
Professionals use alumina as a starting material for producing aluminum metal. Alumina exists as a chemical compound of aluminum and oxygen, and it has a close physical resemblance to table salt. The compound features a boiling point of 2980 degrees Celsius and a melting point of 2040 degrees Celsius.
Alumina refining involves extracting alumina from bauxite using a method called the Bayer process. Most of the world's refineries still use the Bayer process, which was invented in 1887, to produce alumina. From every two pounds of alumina, you can create one pound of aluminum.
The Bayer process involves dissolving bauxite with caustic soda. Filtering is necessary to remove impurities. Professionals move the alumina mixture to precipitators for cooling, and aluminum hydroxide seeds are combined to encourage the creation of aluminum hydroxide crystals. Once the aluminum hydroxide solidifies and settles at the base of the tank, it can be taken out. Aluminum hydroxide must be washed and heated to remove water.
At the end of the refining process, alumina is present as a delicate white powder.
The Bayer process was invented by the Austrian chemist Karl Josef Bayer. When chemists discovered they could combine the Bayer process with the Hall-Heroult electrolytic process, both methods gained popularity in the world of aluminum production. The Bayer process consists of the following steps:
The Bayer process results in alumina, which looks similar to sugar in appearance.
Once alumina is formed, it needs to undergo a smelting process, called the Hall-Heroult process, to produce pure aluminum. The smelting process involves extracting aluminum by methods of heating and melting.
Charles Hall and Paul Heroult simultaneously and independently invented the Hall-Heroult process in 1886. The process is still used today to make aluminum.
The Hall-Heroult process is used to produce most commercial aluminum. It consists of the following steps:
Related: The Aluminum Smelting Process Explained
After aluminum is molded, it's distributed to manufacturers who then turn it into consumer products. A manufacturer will create new aluminum products by remelting them and adding alloys or other materials they need. Pure aluminum does not feature great tensile strength. For this reason, it's often alloyed with small amounts of different materials, such as copper, iron, or titanium, to make it stronger or give it other properties. Manufacturers will then recast the mixture into the desired shape.
Many manufacturers order large aluminum slabs. They roll the slabs into thin sheets for use in foil, can and car panel manufacturing. Aluminum makes an excellent material for producing beverage and food cans, for example. This is because aluminum cans are infinitely recyclable, lightweight, easy to chill, smooth enough for printing labels and good at preserving the product inside.
The term aluminum fabrication describes the process of manufacturing aluminum into a new shape or product. Some of the most common fabrication techniques are outlined below.
Extrusion techniques involve guiding a piece of aluminum through or around a die to reshape the metal. Depending on the product you are manufacturing, it is possible to complete aluminum extrusion methods where aluminum is heated or at room temperature.
Professionals rely on aluminum castings to create products out of molds. With casting methods, aluminum is heated until it changes to liquid form. The liquid metal is then poured into a die or mold where it cools and hardens to take the shape and size of the molding piece.
Aluminum castings are usually created using 4xxx and 5xxx alloys because of their excellent wear resistance.
The forging process requires fabricators to compress aluminum into the desired shape through hammering or beating aluminum sheets. Aluminum forging is necessary when components or products must be exceptionally durable. For example, vehicle parts may be subject to forging techniques to enhance the materials stress-handling capabilities.
Aluminum is flexible and soft. Select alloys like aluminum 3003, which contains manganese, can be rolled into sheets or plates. Fabricators can create large aluminum sections to assemble vehicles, planes, rail cars and other technology.
Decision-makers in the electrical and construction industries rely on aluminum drawing fabrication methods to pull the metal through dies. Aluminum drawing enables workers to stretch the metal into wiring or cans for storing liquids like paint.
Some fabrication jobs require cutting into metal sheets. Machining describes the process of changing the shape and size of a metal product by removing sections.
Aluminum changes form when exposed to heat, so it is crucial to use specialized equipment, tools and lubricants for sculpting aluminum parts and products.
Rather than using heat, fabricators can spray high-pressure water across aluminum surfaces. Waterjet cutting operations allow the alteration of the shape of the metal without changing its original properties as heat would.
Metal fabricators can merge two pieces of aluminum together through metal inert gas (MIG) or tungsten inert gas (TIG) welding procedures. It's possible to attach metal surfaces together by heating an aluminum thread.
Related: Aluminum Rolling Mills Explained
Although aluminum is used in manufacturing a wide array of products, the global aluminum market consists of several industries.
Aluminum is the most widely used and distributed metal in the world. It's also been around for much longer than you might think. For example, an ornament composed of 85 percent aluminum was discovered in the tomb of a third-century Chinese military leader. No one knows how the ornament was produced.
Now, just about every person in the United States uses aluminum every day, whether they realize it or not. It's favored for its malleability, low melting point, and resistance to corrosion.
Since aluminum is 100 percent recyclable, the manufacturing process doesn't end once it reaches the consumer. Many recyclable aluminum products undergo a secondary production process. Secondary production is the process of turning scrap into aluminum that can be used again in the manufacturing of another product.
HARBOR estimates that 53 percent of the aluminum supply in North America comes from secondary production. Over 90 percent of aluminum used in the automotive and construction industries is recycled.
Aluminum cans, in particular, are the most recycled beverage containers in the U.S., and in 2018, over 56 billion cans were recycled. If everyone recycled every aluminum can they used, it could save enough energy to power over four million homes for an entire year.
Here's an overview of how the aluminum recycling process works:
It doesn't take long for recycled aluminum to get back on the shelf again. For example, an aluminum beverage container can be recycled and back on the shelf in about 60 days. Aluminum can be reused over and over again without losing quality.
Related: Aluminum Reycling in the Scrap & Secondary Market
Aluminum is a commodity. Commodities are basic goods that can be bought or sold. They are also interchangeable with other materials of the same type. For example, commodities like oil and gold generally feature the same characteristics, no matter who produces them. Commodities are usually raw materials or agricultural products that are used to produce other goods.
They fall under two different categories: hard commodities such as aluminum, gold, and oil, and soft commodities such as agricultural products, which include corn, wheat, and sugar. Anyone who regularly works closely with aluminum may choose to keep an eye on the commodity market.
Investors and traders can buy commodities directly, or they might purchase futures or options contracts. With a futures contract, the person is obligated to buy or sell a commodity at a predetermined price on a future date. Futures allow traders to profit from short-term price fluctuations. With an options contract, the investor is not required to buy or sell shares at a specific date. Here are some common considerations regarding aluminum commodity trading:
Changes in oil prices, electricity costs, and exchange rates also affect aluminum prices because they impact the production process. Considering the various elements that determine market prices, it's difficult to predict what will happen next.
Related: Aluminum Trading and Pricing Explained
At HARBOR Aluminum Intelligence, we help purchasing managers, marketing and sales executives, investors, and industry analysts better navigate the aluminum market. We deliver to our clients, detailed price reports, market intelligence, and expert insight for all relevant aluminum products (including scrap items).
If you need aluminum market intelligence and insight from a firm with decades of industry experience, contact HARBOR Aluminum, or subscribe to our market intelligence reports today.
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This article was published in partnership with Grid.
Historically, the global aluminum industry curbed emissions of one of the most potent greenhouse gases using a surprisingly simple method: a stick. Standing over a huge bubbling pot of molten aluminum, workers would plunge a long wooden pole into the pot to stop a chemical reaction that disrupted aluminum production and released the powerful emissions.
Stephen Andersen, director of research at the Institute for Governance and Sustainable Development (IGSD), an environmental organization based in Washington, D.C, recalled his reaction when he first saw the process at a U.S. smelter in the early 2000s.
“It didn’t look like a sophisticated company managing a chemical process,” Andersen said. “It was almost like witchcraft.”
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See jobsPerhaps unsurprisingly, the stick method wasn’t the most effective. By the 1990s, Western companies were using an automatic system to stop the “anode effect”—the chemical reaction responsible for the emissions. But long after most aluminum producers had left the “stick” behind and automated their operations, one critical country was lagging: China, where more than half of the world’s aluminum is now produced.
An investigation by Inside Climate News and Grid found that even as China has made bold new commitments to address climate change, the country’s aluminum giants continue to use the antiquated stick method, allowing the potent emissions to slip into the atmosphere.
This decision—to stick with the stick, as it were—may seem like a technical detail for plant engineers, but it has significant consequences for the world. That’s because the emissions in question, called perfluorocarbons or PFCs, are some of the planet’s most damaging greenhouse gases. They are part of a group of gases known as “the immortals”—as in, once they go up into the atmosphere, they remain there, heating the planet for tens of thousands of years.
China’s aluminum industry is one of the world’s great climate polluters. A 2021 report by Ember, an energy think tank based in London, concluded that the collective emissions from aluminum production in China, including power production, exceeded all the 2020 greenhouse gas emissions from Indonesia, the world’s 8th largest emitter.
And while PFC emissions are a small fraction of all greenhouse gas emissions tied to aluminum production, the potency and longevity of PFCs make them particularly concerning. According to the UN’s Intergovernmental Panel on Climate Change, tetrafluoromethane (CF4), the primary PFC released in aluminum production, is 7,380 times worse for climate change than carbon dioxide on a pound-for-pound basis. And unlike CO2, which remains in the atmosphere for approximately 300-1,000 years, CF4 remains in the atmosphere, warming the planet, for 50,000 years.
Each year, aluminum producers in China collectively release approximately 6,000 tons of CF4 and hexafluoroethane (C2F6), another of the world’s most potent and long-lasting greenhouse gases, according to a 2021 study published in the Journal of Geophysical Research: Atmospheres. The pollutants, collectively known as PFCs, have a climate impact equal to the annual greenhouse gas emissions of 10.2 million automobiles, according to the U.S. Environmental Protection Agency.
China plays a disproportionate role in releasing these particular “immortal” gases. The country is responsible for 81 percent of the industry’s PFC emissions, despite producing only 55 percent of global aluminum, according to official estimates reported in the 2021 study. Actual PFC emissions from China’s aluminum industry may be even higher, based on atmospheric measurements of PFC pollution reported in the study.
Anode effects account for nearly one third of PFC emissions at Chinese plants, according to a 2015 study published in the Journal of The Minerals, Metals & Materials Society. Reducing the occurrence of these chemical reactions is critical.
More than a decade ago, in 2009, a team of international experts traveled to China to demonstrate an automated control system that could end dependence on the stick method, and dramatically reduce PFC emissions. The experts were working as part of the Asia-Pacific Partnership on Clean Development and Climate, a voluntary program funded in part by the U.S. government.
When a chemical imbalance occurs in a pot of molten aluminum, electricity running through the pot to help break aluminum oxide down into aluminum has to be disrupted to reset the process. Historically, this was the moment when a worker would rush to the pot and stir the molten aluminum with a stick until the liquid metal splashed upward, making contact with the anode at the top of the pot, causing the smelter to short circuit.
A worker using a wooden pole to manually disrupt the “anode effect” in an aluminum pot at a Reynolds aluminum smelter in Baie-Comeau, Quebec Canada in 1992. Credit: Alton TabereauxThe automated control method, developed in the 1970s by U.S. manufacturer Reynolds Aluminum, simply lowered the anode further down into the pot until it made contact with the molten aluminum, achieving the same short-circuiting effect. No stick, and no human being to wield it, required. And it had a significant effect on the “anode effect.”
“In the old days, [the anode effect] could last anywhere from one to three minutes,” said Alton Tabereaux, who worked as a research and technology development manager for Reynolds Aluminum and Alcoa from the 1970s to the early 2000s. “Once we saw that duration was producing a lot of PFCs, then we designed the anode moving down [sic] very quickly, and we could actually terminate the anode effect in 30 seconds. And some plants were even faster than that. It made a tremendous decrease in PFC emissions.”
Tabereaux helped develop the automated method nearly half a century ago and was part of the team of researchers that traveled to China to demonstrate the technology in 2009.
Demonstrations at the Henan Zhongfu Industrial Company, a large Chinese aluminum producer, showed that the automated process cut the average anode effect duration by 53 percent, from 28 seconds to just 13 seconds, according to a 2011 study published in the journal Light Metals.
In addition to reducing emissions, the new technology also yielded a slight increase in plant efficiency, according to the study.
The researchers assumed that the clear success of their demonstration would lead to widespread adoption in aluminum smelters across China. After all, it wasn’t just good for the planet; it might also boost profits.
“From our study, it looked like they could actually make more money by being slightly more efficient,” said Durwood Zaelke, president of IGSD, whose organization coordinated the project. “We thought, ‘this is so obvious that it’ll sweep the 100 smelters in China’ at the time.”
It didn’t happen.
Thirteen years after the initial demonstration, Chinese smelters largely continue to rely on manual controls to kill anode effects, industry experts in China told Grid and Inside Climate News.
A survey of Chinese smelters in 2016 by Chinese industry experts found the vast majority continued to use the manual method. The group polled the operators of seven smelters, representing 10 percent of Chinese production, and found that six out of seven relied exclusively on manual methods to cut off anode effects.
More recently, researchers with Henan Zhongfu Industrial Company, the aluminum smelter that hosted the 2009 demonstration, confirmed the industry’s ongoing reliance on manual controls.
“To date, very few domestic electrolytic aluminum factories have used the automatic approach to extinguish the anode effect,” the authors wrote in a study published in the academic journal Engineering Technology Research in 2020.
Chen Xiping, a material science professor at Zhengzhou University in Henan Province, told Grid that anode effects have become less frequent with the use of some automated systems in the prevention phase, but that the reliance on the stick method persists.
Along with those preventative measures, “companies also use [the stick],” Chen said. “Relatively few domestic companies use the automatic anode lowering method.”
The authors of the 2020 study wrote that the use of automated control methods isn’t widespread because the necessary computer software hasn’t been widely installed.
However, David Wong, an aluminum industry expert with Atmolite Consulting in Brisbane, Australia who led the 2009 demonstration in China, said there is another reason why companies haven’t installed the software.
Wong said plant operators in China typically run their smelters with volumes of molten aluminum that are higher than what the aluminum pots were designed to hold. If the anodes at the top of the pots were quickly dunked further into the pots to kill the anode effect, the pots could overflow. This would cause the molten salt at the top of the pot to spill out. Such an overflow could create an explosion hazard if the liquid level inside the pot dropped too low.
Wong said he has suggested to plant operators in China that they run their aluminum pots with less aluminum, but that Chinese companies decided to take a different course.
Maintaining the proper chemical balance to maximize aluminum production efficiency is a constant challenge for aluminum plants worldwide. Further compounding the issue, plant operators in China run their smelters at a lower voltage than smelters elsewhere in the world to try to reduce energy demands and therefore cut costs, Wong said. But operating at lower voltage can compromise plant efficiency, increase PFC emissions, and make it harder to maintain a proper chemical balance, he said.
According to Wong, extra molten aluminum is added as a way to mitigate the impact of some of the imbalances that would otherwise compromise production efficiency.
“When you operate with higher liquid levels, you can sometimes mask the problems,” Wong said. “The problems go away—but problems return. It’s a less efficient way of operating in our opinion.”
In November, the Chinese government released a plan for reining in carbon emissions in the non-ferrous metals sector, which includes aluminum. The plan contains a goal of getting 30 percent of electricity for aluminum production from renewable energy sources by 2030, and significantly increasing the amount of non-ferrous metals sourced from recycled materials in China by 2025.
Any increase in recycling would reduce both energy needs and PFC emissions, but PFC emission reductions were not explicitly included in the measures.
Although the government hasn’t yet required aluminum companies to reduce the industry’s PFC emissions, the problem is on its radar. One sign: Chinese government guidelines for metals companies to voluntarily calculate their emissions included a formula for assessing PFC emissions.
The rates recommended by the government agencies nearly a decade ago—and again in an updated document this year—are significantly lower than current emissions from Chinese smelters as estimated by the International Aluminium Institute, perhaps reflecting a lack of awareness of the companies’ antiquated methods.
Individual companies in China are not required to publicly disclose PFC emissions, making it difficult to track progress on pollution reductions.
“More disclosure on emission hot spots or industrial-specific emission sources, such as PFCs emission for aluminum enterprises, are necessary to provide stakeholders, especially decision-makers and researchers empirical data to work on,” Lindsey Zhu, green supply chain senior project officer at China’s Institute of Public and Environmental Affairs, told Grid in an email.
U.S. officials are considering climate-related tariffs on steel and aluminum aimed at Chinese production, and European policymakers are inching closer to a broader “carbon border adjustment mechanism” that would apply to imported steel, aluminum and other products. In time, these policies may put further pressure on Chinese aluminum makers to reduce their emissions.
In China today, it appears that at least one company, Henan Zhongfu, is making use of the automated method. In their study on the automated control technology, researchers at the company said they save an estimated 1,663,500 yuan, or approximately $240,000 per year, on electricity by using the automated method instead of the stick method.
In addition, the study’s authors noted that the automated controls greatly reduce the need for all those sticks—nearly 8,000 of them at their facility each year—saving the company an additional 11,826 yuan, or approximately $1,700 annually.
If similar savings could be realized across all of China’s 88 aluminum smelters, the cost savings would come to approximately $21 million per year, based on an Inside Climate News assessment.
Tabereaux, who helped develop the automated control technology in the 1970s, said cost savings aside, it’s time China implemented the less polluting technology to rein in those “immortal gases.”
“It makes me kind of think that what we’re doing in the U.S. and Europe doesn’t really amount to much compared to what China is doing,” Tabereaux said of the Chinese industry’s continued reliance on manual controls. ”The emissions they generate are so much more.”
Lili Pike is a China reporter at Grid focused on climate change, technology and U.S.-China relations.
Editor’s note: An earlier version of this story attributed the 2016 survey of Chinese smelters to the International Aluminium Institute; it has been updated with correct attribution.
Phil McKenna is a Boston-based reporter for Inside Climate News. Before joining ICN in 2016, he was a freelance writer covering energy and the environment for publications including The New York Times, Smithsonian, Audubon and WIRED. Uprising, a story he wrote about gas leaks under U.S. cities, won the AAAS Kavli Science Journalism Award and the 2014 NASW Science in Society Award. Phil has a master’s degree in science writing from the Massachusetts Institute of Technology and was an Environmental Journalism Fellow at Middlebury College.