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Recycled Aluminum vs Pure Aluminum

Recycled Aluminum vs. Pure Aluminum

Aluminum is the most abundant metal on earth. The physical and mechanical properties of aluminum make it the ideal choice for parts that can be used in almost any industry. Aluminum is corrosion resistant, durable, and has a high strength-to-weight ratio.

Benefits of choosing aluminum for your part

When considering the type of metal for an application, many companies put aluminum at the top of their list. With its unique mechanical and physical properties, aluminum offers design engineers significant advantages. The metal creates lighter parts with more surface finishing options than other die cast alloys. It can also withstand the highest operating temperatures of all the die cast alloys, making it a great choice for products that require heat dissipation, like computers and handheld devices. And moreover, cast aluminum is versatile, corrosion resistant, and retains high dimensional stability with thin walls that can be used in almost any industry.

 

With all the benefits aluminum offers, it may come as a surprise that a majority of aluminum is actually mixed with other materials such as magnesium, iron, and copper. That's because the use of pure aluminum, or primary aluminum, in casting is quite costly due to the high amount of energy used during extraction. Recycled aluminum, or secondary aluminum, is much more cost-effective and readily available – not to mention, good for the Earth.

 

Discover additional benefits of aluminum die casting metals in our Knowledge Center's Material Information section.

 

Cold Chamber | Die Casting | Recycled Aluminum 

How do you extract pure aluminum?

150 years ago, aluminum was more expensive than gold—not because of how rare it was, but how expensive it was, and still is, to extract. Production of primary aluminum is quite demanding and costly.

 

In its purest state, aluminum is extracted from a clay ore called bauxite. The bauxite ore is purified to yield a fine white powder, aluminum oxide. Aluminum ions are separated from the oxide through electrolysis—a process in which aluminum sinks to the bottom of a melt tank in liquid form and is withdrawn and solidified to become the metal we recognize as aluminum.

 

Extracting primary aluminum is not only energy-intensive, running up a costly bill with the amount of electricity used, but environmentally detrimental. Large amounts of CO2 are leaked into the atmosphere during the extraction process, making recycled aluminum the perfect alternative for a more energy efficient source of aluminum.

Recycled aluminum

Aluminum is 100% recyclable. And 75% of all the aluminum ever produced is still in use today. Since aluminum maintains all of its physical and mechanical properties, it makes the perfect, greener replacement to primary aluminum.

 

Secondary aluminum begins by being extracted from various waste streams. Scrap is separated by chemical composition—with purer forms of recycled aluminum maintaining the highest value and aluminum with mixtures of other alloys and other having the lowest. Since aluminum is non-magnetic, contaminants from the scrap are removed using magnets to remove debris. The remaining aluminum is shredded into small pieces, stripped of existing surface finishes and melted down to purify the molten metal. The final product is an aluminum alloy with pure aluminum properties.

Closed loop recycling

Industrial scrap, or discarded metal from manufacturers and other foundries, is a key source for providing suppliers with material for recycling. At Dynacast, we send off all scrap that was produced as a by-product of our operations to be recycled and used for future projects. The closed loop cycle prevents waste from going to landfills.

 

Consumer products make up the remaining scrap that gets recycled. Items like aluminum window frames are sorted, shredded, cleaned and melted before removing all byproducts. At this point, other alloys can be added to the aluminum, creating an almost-exact recreation of primary aluminum.

 

Closed Loop Recycling | Aluminum Die Casting | Aluminum Casting 

Savings from recycled aluminum

The amount of energy used to produce aluminum is the ultimate differentiator when it comes to cost. Primary aluminum extraction uses a great deal of energy, consisting mainly of electricity, natural gas and liquified petroleum gas consumption. The aerospace industry is most commonly known for using primary aluminum due to strict regulations and quality measures. Using secondary aluminum is a more energy-efficient choice than extracting pure aluminum since secondary aluminum casting can produce a large amount of usable material with less effort. To put it in perspective, recycled aluminum uses approximately 90% less energy than mining for pure aluminum.

 

Most of the energy consumption in aluminum die casting is used to heat and remelt the metal during fabrication. For this reason, Dynacast is able to save more time, energy, and money by remelting in-house. And since a majority of products can be cast out of secondary aluminum, while still maintaining like properties and material characteristics, recycled aluminum can be a solution for your next design.

To learn more about our thin wall aluminum casting capabilities, contact our engineering team today.

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Last updated 11.04.2020