Casey walks out of his CE2: Materials and Methods class on a hot morning and heads to the Campus Center for something refreshing to drink. He grabs a nice cold coke out of the refrigerator and begins to drink. How did this coke get into his hand? Where did it come from? In the beginning there was just bauxite (aluminum ore) probably from either the Australian outback or Jamaica. It is often found in extremely weathered rocks. Before mining, at least the top six inches of top-soil must be removed from the site. Because bauxite is found near the surface of the ground (usually less than 100 feet) it is often mined by simple opencast methods. Bauxite mining destroys more surface area than mining any other ore. From bauxite, alumina (Al2O3) is still most commonly extracted using a method that was developed back in 1888.
The amount of alumina produced is approximately half the weight of the original bauxite. A byproduct of caustic soda is captured for reuse and another toxic byproduct known as “red mud” is usually put into a nearby pond where some of it inevitably leaks into ground water. Next, the alumina is shipped across the world for further processing using tons of energy and polluting the oceans.
Then the alumina is smeltered. Smelting is very energy intensive: making a single soda can of smelted aluminum is equivalent to a quarter-can of gasoline. In the smelting process the alumina is dissolved in huge pots filled with cryolite (sodium aluminum fluoride) while carbon electrodes are added to the pot to send a giant 100,000 amps electricity. In the process Carbon Dioxide is produced along with perfluorocarbons (PFCs).
PFCs, which are greenhouse gases, trap heat like none other. PFCs are one of the most harmful greenhouse gases to exist. The global warming potential (GWP) for perfluorocarbons is 6,500-~ 9,200, compared to Carbon Dioxide with a GWP of 1. GWP is the ability of a greenhouse gas to trap heat in the atmosphere relative to an equal amount of carbon dioxide. Smelting is therefore one of the most destructive processes to the climate.
The next step in the process is shipping/trucking the aluminum slabs to a factory where the aluminum is flattened and then shipped to the next mill. At this mill the aluminum is shaped into a can and printed with design. The can is then baked twice and then sent to the next factory. The can itself cost more than the soda which will fill it.
Here the can is filled with soda containing 90% water. The bottling plant combines corn syrup, citric acid, flavors, preservatives, caffeine and artificial coloring, water and carbon dioxide in order to make the soda. The corn syrup most likely comes from Iowa where a plant turns corn kernels into corn syrup using water, enzymes, acids, heat, grinders and centrifuges. Now the product is already to go and is shipped across the country to stores and restaurants and machines where it will be bought.
For all the time it took to produce Casey finishes his coke in just a few minutes. On his way out of the Campus Center Casey throws his can in the:
b.) Recycling bin #1
c.) Recycling bin #2
a.) Trash: Without thinking Casey carelessly threw his coke can into the trash can where it is transported to the dump. Here is sits for 500 years before it is decomposed. Meanwhile more aluminum ore is being harvested from the earth only to go through the same energy wasting process.
b.) Recycling bin #1: Casey realizes the enormous benefits of recycling and puts his can in the recycling bin. However, some other not so intelligent students have thrown away their trash in the same bin. Sadly, with so much contamination all of the cans in the bin cannot be recycled and must be thrown out with the trash to spend their 500 years in the landfill.
c.) Recycling bin #2: Fortunately this recycling bin is not contaminated thanks to the environmentally conscious Tufts students and it gets picked up by Conigliaro Industries. Here the can gets sorted from the other plastics and glass bottles and is compacted for efficiency. Then the bail with the can is shipped to another plant where it is shredded, melted down, and eventually comes back to life as a new can. Recycling the can took approximately 75%-95% less energy than it took to create one from scratch.
Information about the life cycle of an aluminum can was taken from Stuff: The Secret Lives of Everyday Things, written by John C. Ryan and Alan Thein Durning, published in 1997 by Northwest Environment Watch.
Metal Can General Info
The difference in energy use between virgin aluminum and recycled aluminum is very large. Theoretically, producing recycled aluminum requires 95% less energy than producing aluminum from bauxite, an aluminum ore. In practice, energy savings achieved are closer to 75%.
Aluminum cans are the most common form of aluminum which is recycled; but other products such as aluminum siding, lawn furniture frames, window frames and storm doors are also recyclable. For each pound of aluminum recovered, Americans save the energy resources needed to generate about 7.5 kilowatt-hours of electricity. That’s enough energy saved each year by recycling aluminum to meet the lighting needs of a city the size of Pittsburgh, PA for six years [Can Manufacturers Institute].An estimated 80,000,000 Hershey’s Kisses are wrapped each day, using enough aluminum foil to cover over 50 acres of space — that’s almost 40 football fields. All that foil is recyclable, but not many people realize it [Recycling Revolution].
There is no limit to the amount of times an aluminum can can be recycled. At one time, aluminum was more valuable than gold [Recycling Revolution]!