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Aluminum Can Be A Sustainable Material, But It’s Complicated.

by Rudy Sanchez on 10/22/2019 | 3 Minute Read

Aluminum’s strength, lightness, and resistance to corrosion has lead to the usage of the material in everything from planes to beverage containers, and unlike plastic, it is infinitely recyclable. 

Over 96 billion cans are produced in the United States alone—that’s a lot of soda, beer and creamed corn. The automotive industry has increasingly turned to aluminum to meet stricter fuel efficiency standards as it has similar properties to steel but weighs half as much. Modern air travel would not be possible without aluminum as 75-80% of the plane you're flying in is made up of aluminum.

But as brands continue to set sustainability goals—particularly around using less plastic—some are looking to aluminum as a greener alternative. But do the downsides of the metal outweigh the positives? Mining the substance comes with a steep ecological cost, and the rate of post-consumer aluminum that is put back into new products is subject to economic externalities. 

Aluminum is the most abundant metal on earth, but you can only find it in bauxite near the Earth’s surface. The substance mostly gets strip-mined, and it's a process that can pollute the surrounding area’s water with heavy metals and other contaminants, as well as destroying vegetation and crops. The production and transport of the substance is also thought to cause health problems such as asthma.

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Aside from the environmental impact, the element's reusable bona fides make it the ideal material for packaging, the perfect closed loop substrate. So, we don't need to dig anymore up, right? 

It would stand to reason that the only aluminum mined would be whatever additional amount of the substance necessary after recycling all of the existing aluminum. But, global economic forces being what they are, the market for recycled aluminum isn't as robust as one would think.

Aluminum is usually mixed with other metals to create alloys that tweak the element's properties, tailoring the resulting metal for the intended application. 

Alloys are designed by different, four-digit series classifications, based on composition. Aluminum cans are made of 3000 and 5000 series alloys, meaning that aluminum gets mixed with manganese and magnesium. Automotive manufacturers and tech giants like Apple use 6000 and 7000 series alloys, which contain silicon and zinc. Aluminum manufacturers are shifting production away from can sheet to meet the increasing—and more lucrative—automotive and electronics market, and typically, they want the virgin stuff.

The reduction in can sheet production has led to a glut of unused cans, as reported by The Wall Street Journal earlier this year. This lack of domestic can sheet production means that the beverage industry is importing can sheet, despite the additional cost brought on by tariffs and the stockpiles of unprocessed recycled cans.

“We’d prefer to purchase domestic can sheet, but as of right now, there is not enough to supply the domestic market,” Jamie Westfahl, senior director of global packaging procurement for Molson Coors, told the Journal.

While tons of cans dutifully collected sit unrecycled, consumer pressure for companies to operate more sustainably grows. Aluminum has the potential to create a more circular life for beverage containers, but given the economic disincentive to create new sheet metal out of old cans, the solution isn’t so cut-and-dried for beverage companies, although some experimentation with replacing plastic for aluminum is happening.

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While a can of Coke isn’t going to become the hood of an F-150 or a MacBook Pro, some companies have found ways to reduce the need for destructive mining. Apple estimates that its efforts have resulted in avoiding the digging of 900,000 metric tons of bauxite oxide. Ford recycles the scraps of metal leftover during manufacturing and says it can use 90% of the original material in the manufacturing process.

Plastic is inorganic, comes from petroleum, a non-renewable resource, the quality goes down when recycled, and it takes hundreds of years to degrade fully, if at all. So while aluminum mining has some very serious drawbacks, it also has the potential to create a circular life for food and beverage packaging, hampered only by economic forces rewarding the production of virgin aluminum instead of its recycled counterpart. Reducing the environmental impact of bauxite ore mining requires incentivizing aluminum companies to produce recycled metal.

In other words, the material is already there, and brands need to step it up.