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Aluminum: How It's Made

Written by Aleesha Crimmins

Nov 1, 2021 7:52:16 AM

 

 

How It Started

The process of producing aluminum has been around for centuries. The primary industrial revolution of aluminum was founded in 1886 by Charles Martin Hall and Paul Heroult. Martin later founded the first large-scale production plant in Pittsburgh. Since 1886 the production of aluminum has been happening worldwide as demand accelerated.

In the 19th century, aluminum was considered rarer than gold or silver due to the complexities surrounding refining aluminum. Once perceived as highly precious, you can now find aluminum in typical applications: signage, automotive, transportation, aerospace, construction, and energy are just a few of the spaces where aluminum is quite commonly used.

The Process

Mining

Mining aluminum imageThe primary source of aluminum is bauxite ore, which must be chemically processed first to produce alumina. Alumina is smelted using an electrolysis process to create pure aluminum metal. Bauxite Ore is extracted from dirt/topsoil from the earth in tropical and subtropical regions. Roughly 70% of the world’s bauxite production is refined through the Bayer chemical process into alumina.

 

Refining

Alumina, commonly known as aluminum oxide, is extracted from Bauxite Ore - done by grinding ore and mixing with Caustic Soda (Sodium Hydroxide) called Slurry. The slurry is treated in a high-pressure container and heated to 230-250 degrees, making alumina. When refined from Bauxite, alumina is a white powder, appearing to look like table salt or sugar but tough and durable enough to scratch glass. Alumina has extensive uses in the industry beyond being a key component in the production of aluminum. It is also a key component in producing spark plug insulators and metallic paint, and it’s used as a fuel component for rocket boosters.

Aluminum refining visual

 

Smelting

Smelting process imageSmelting is the process of turning alumina into aluminum. Smelting happens after the refining process, and after alumina is extracted from Bauxite Ore. The alumina is smelted into pure aluminum metal through this process. Turning alumina into aluminum is done by Electrolytic Reduction, where alumina is dissolved in a Cryolite Bath inside lined pots with Carbon. Aluminum metal separates from the chemical solution after an electrical current passes through the bath, separating it. You can find that most smelting facilities are in North America.       

 

Fabrication

After the Smelting process, aluminum goes into a furnace for further mixing to form various alloys. The metal goes through a purification process and pours into molds or is cast into ingots. The metal must go through a cleaning process known as fluxing where nitrogen and argon are used to separate impurities and bring them to the surface. After molding or casting into an ingot, aluminum will undergo further fabrication, including casting, rolling, extruding, or forging. The final step of fabrication is the conversion process. The conversion process involves converting aluminum into a usable product for many industries. In the sign, industry aluminum is converted from ‘master coils’ into sheets, blanks, and smaller coils. One of the main reasons for aluminum’s popularity with fabrication is due to it being lightweight with a higher strength-to-weight ratio than other materials, and aluminum is reasonably easy to work with.

Fabrication of aluminum

Grimco Knows Aluminum

Grimco is a leading converted and distributor of aluminum for the sign and traffic industry. Since 1875 Grimco has evolved from stamping badges and license plates to providing aluminum sheets, traffic sign blanks, channel coil, and other aluminum products to the industry. Grimco processes millions of pounds of aluminum annually to serve our customers. 

 

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