Aluminum Production

In 1827, a German chemist named Friedrich Wöhler (picture on the left) produced about one gram of aluminum for the first time. The chemist obtained this first aluminum using a chemical method (that is, based on the reduction reaction between aluminum chloride and potassium). This method is quite expensive for industrial use. After the electric dynamo was discovered by the English chemist and physicist Michael Faraday (1791–1867), aluminum began to be produced by electrolysis.

Although aluminum is the third most abundant element on Earth after oxygen and silicon, aluminum production doesn’t have a very long history. We can say that industrial aluminum manufacturing began in 1886, when the electrolysis method started being used.

How Is Aluminum Produced

Because of its chemical reactivity, aluminum doesn’t occur in its free (elemental) state; its compounds are spread throughout nature.

It’s found in “feldspar,” and in the composition of “kaolin” and “clay” formed through the weathering of feldspar. Other aluminum ores include the following.

Bauxite, cryolite, corundum, and spinel — even though aluminum ores are found abundantly in nature, extracting aluminum metal from them was burdensome until electrolysis methods reached maturity. Because the electrolysis method uses electricity.

Bauxite ore, the raw material of aluminum (above)

Aluminum production takes place in two stages. In the first stage, alumina is obtained from bauxite ore using the Bayer process. In the second stage, aluminum is obtained from alumina by electrolysis.

A view of a bauxite mine (above)

The First Stage of Aluminum Production: Alumina (Aluminum Oxide)

Alumina refineries are generally built near bauxite ore deposits. The bauxite ore extracted from the mine is treated with a caustic soda solution to obtain aluminum hydroxide. The insoluble residue (red mud) resulting from this process is separated out, and “alumina” (aluminum oxide) is obtained by calcining the aluminum hydroxide.

Alumina appears as a white powder. The formula for alumina is Al₂O₃.

The Second Stage of Aluminum Production:  Electrolysis

This stage is the conversion of alumina into aluminum. Pure aluminum oxide, dissolved in molten cryolite, is electrolyzed. The goal of aluminum electrolysis is to separate the aluminum from the oxygen.

An iron chamber lined with graphite is filled with cryolite. (Cryolite is a mixture of aluminum and sodium fluorides, with the formula Na₃AlF₆. It’s synthetically manufactured for aluminum production). The chamber is then connected to the electric current so that it forms the (−) cathode, while graphite rods lowered into the chamber from above form the (+) anode. Because of cryolite’s resistance, the heat generated in the furnace by the passing electric current melts the cryolite (1000°C). After this, aluminum oxide is added to the molten cryolite mass and electrolysis begins. Molten aluminum collects at the bottom of the furnace.

The electrolysis method is also known as the Hall-Héroult process.

A worker at the electrolysis cells in an aluminum factory (above)

Molten aluminum is poured into ingot-shaped molds before it solidifies, and the resulting aluminum ingots are packaged, ready for sale on the international market. (above)

How Much Electricity Does Aluminum Production Consume?

In the early days, energy consumption for each ton of primary aluminum produced was 42,000 kWh/ton; today, thanks to technological advances, this has dropped to an average of 16,500 kWh/ton. With the very latest technology, this figure is 13,000 kWh/ton.

Producing Aluminum Through Recycling

Refining aluminum requires a very large amount of electrical energy; by comparison, the recycling process uses only 5% of the energy used in production. For this reason, recovering aluminum from scrap has become an important component of today’s aluminum industry.

The recovery process is based simply on remelting the metal. Recovery has been practiced since the early 1900s. Recycling activity, which remained a low-profile activity until the late 1960s, intensified during that period once beverage cans began being made from aluminum. Other recycled aluminum sources include automobile parts, windows and doors, appliances, and containers.

Country Rankings in Aluminum Production

If we’re wondering what the world ranking in aluminum production is: electrical energy makes up 20-40% of the cost of producing aluminum, depending on the plant’s location. For this reason, aluminum-producing businesses tend to be located near regions with abundant, cheap electrical energy, such as South Africa, the South Island of New Zealand, Australia, China, the Middle East, Russia, Iceland, and Quebec in Canada.

Despite not having particularly cheap electricity and having limited aluminum resources within the country, China is the world leader in aluminum production, accounting for 42% of world aluminum production on its own.

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