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The Aluminum Production Process Explained

aluminum process main graphic

How Does the Aluminum Production Process Work?

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. 

In general, making aluminum 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.

Step 1: Bauxite Mining

The first step in primary aluminum production is bauxite mining. Bauxite is the leading source of aluminum. A bauxite rock does not have a specific composition. Instead, it contains aluminum minerals along with clay minerals and other insoluble materials such as quartz. Bauxite is usually found in the topsoil in tropical and subtropical regions and is abundant in Africa, South America and Oceania.

bauxite mining

Clear the Land and Remove the Topsoil

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.

Break, Load and Transport

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.

Next, the bauxite is shipped to an alumina refinery. Most alumina refineries are located near the mines.

Although bauxite has a few other 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.

Step 2: Bauxite to Alumina

The second step in aluminum production is alumina refining. 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.

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 Explained

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:

1. The bauxite is crushed, washed and dried.

2. Next, a heated sodium hydroxide solution is used to dissolve the bauxite.

3. The mixture undergoes a filtration process to remove impurities known as "red mud."

4. The solution containing oxides of aluminum is transferred to a tank called a precipitator.

5. In the precipitator tank, the solution cools, and small aluminum hydroxide particles are added to stimulate the growth of solid aluminum hydroxide crystals.

6. The aluminum hydroxide crystals settle at the bottom of the precipitator tank and are removed.

7. The aluminum hydroxide is then washed to clean off residue and then heated to remove excess water.

The Bayer process results in alumina, which looks similar to sugar in appearance.

Step 3: Alumina to Aluminum

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.

alumina to aluminum

The Hall-Heroult Process

The Hall-Heroult process is used to produce most commercial aluminum. It consists of the following steps:

1. In a carbon-lined pot, alumina is dissolved in a bath of molten cryolite. 

2. Carbon anodes, which are used to conduct electricity, are placed in the pots.

3. An electric current passes through the anodes and the alumina-cryolite mixture. 

4. The electricity keeps the mixture extremely hot and allows the alumina to separate into aluminum and oxygen.

5. The molten aluminum is siphoned from the pots and transferred to a casthouse to be formed into blocks, called ingots, slabs or other shapes.

How is Aluminum Distributed? 

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 it and adding alloys or whatever 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.

Food and beverage manufacturers can use aluminum to provide customers with products that have the longest shelf life possible. Although aluminum is used in manufacturing a wide array of products, the global aluminum market consists of several industries:

Packaging

Aluminum has been used as a form of food and beverage packaging since the early 1900s. You'll find aluminum foil encasing everything from candy to frozen dinners. The demand for aluminum packaging continues to grow to meet the rise of processed food consumption in developing countries.

Automotive

As car manufacturers look to replace steel with aluminum, which is much more lightweight and can increase fuel efficiency, it's fulfilling a vital role in the industry.

Construction 

Aluminum is used in construction as an energy-efficient and sustainable building material. China has the highest demand for aluminum as a construction material. In America, you'll commonly find aluminum used in windows and doors.

Aerospace

Aluminum has been used in the development of aerospace technology since the Wright brothers used the metal in building the engine for their first biplane. Since then, it's been used to construct both aircraft and spacecraft. Aluminum alloys are valued for their lightness and mechanical stability, which makes them ideal materials for flying vehicles. NASA's spacecraft, the Orion, is constructed with an aluminum-lithium alloy.

Electrical

Aluminum has been used in electrical wiring since the start of the 20th century. After World War II, aluminum wiring quickly grew in popularity and started to replace copper. It's now the preferred choice for conducting electricity. 

Appliances

Aluminum can be found in household items ranging from washing machines to smartphones and makes it possible to enjoy many modern amenities. For example, aluminum is used to make a lightweight TV casing, so that consumers can mount their TVs on the wall. 

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. 

What Does the Aluminum Recycling Process Look Like?

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.

 

recycling aluminum

 

Here's an overview of how the aluminum recycling process works:

1. A consumer tosses aluminum products, such as beverage cans, in a recycling bin.

2. A recycling company collects aluminum products and transports them to a treatment facility. 

3. The scrap aluminum is sorted and cleaned.

4. The scrap metal is loaded into a furnace and turned into molten aluminum, which removes any coatings and inks.

5. The melted aluminum is poured into molds and cooled to form ingots, which can then be used to manufacture any aluminum-containing product.

6. The ingots may be rolled into a sheet or another shape.

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.

Understanding the Aluminum 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 option 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.

Commodities are usually sold and purchased through futures contracts on exchanges. An exchange refers to the marketplace where commodities are traded. The London Metal Exchange (LME) is the main international exchange for trading metals.

Commodities are incredibly volatile and require monitoring every day. The global supply can change quickly and be affected by various factors. Even someone who doesn't invest in or trade commodities might want to watch the market. For example, a manufacturer of aluminum products might follow the price of aluminum carefully, because it will affect their operating costs.

Commodity prices are unpredictable, but as a general rule, they're affected by supply and demand. Usually, greater demand and lower supply lead to higher prices, and an oversupply leads to lower prices. With that in mind, many factors impact aluminum prices, such as the demand for metal in auto and aerospace manufacturing, and construction growth rates.

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.

Contact HARBOR for Aluminum Prices & Market Forecasting

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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.