Thursday, August 7, 2008

Aluminum Cans

I was at a restaurant with a friend yesterday and was feeling really low on energy. It was hot, so I ordered a coke, something which I rarely do. As you can see from yesterdays haul, the coke came not in a glass, but in a can. Now I'm the first to admit that if it comes in a glass there is still waste involved, but it is not anything that i can quantify, and not specifically as a result of me as those bags of Coke goo get used for many many drinks. But the can is another thing entirely. I think I posted a piece about aluminum cans a while ago, but I figured it might be high time to throw it up again. Think you know how much energy goes into that can? I thought I had an idea, but boy was I wrong. Read on.

A striking case study of the complexity of industrial metabolism is provided by James Womack and Daniel Jones in their book Lean Thinking, where they trace the origins and pathways of a can of English cola. The can itself is more costly and complicated to manufacture than the beverage. Bauxite is mined in Australia and trucked to a chemical reduction mill where a half-hour process purifies each ton of bauxite into a half ton of aluminum oxide. When enough of that is stockpiled, it is loaded on a giant ore carrier and sent to Sweden or Norway, where hydroelectric dams provide cheap electricity. After a monthlong journey across two oceans, it usually sits at the smelter for as long as two months.

The smelter takes two hours to turn each half ton of aluminum oxide into a quarter ton of aluminum metal, in ingots ten meters long. These are cured for two weeks before being shipped to roller mills in Sweden or Germany. There each ingot is heated to nearly nine hundred degrees Fahrenheit and rolled down to a thickness of an eighth of an inch. The resulting sheets are wrapped in ten-ton coils and transported to a warehouse, and then to a cold rolling mill in the same or another country, where they are rolled tenfold thinner, ready for fabrication. The aluminum is then sent to England, where sheets are punched and formed into cans, which are then washed, dried, painted with a base coat, and then painted again with specific product information. The cans are next lacquered, flanged (they are still topless), sprayed inside with a protective coating to prevent the cola from corroding the can, and inspected.

The cans are palletized, forklifted, and warehoused until needed. They are then shipped to the bottler, where they are washed and cleaned once more, then filled with water mixed with flavored syrup, phosphorus, caffeine, and carbon dioxide gas. The sugar is harvested from beet fields in France and undergoes trucking, milling, refining, and shipping. The phosphorus comes from Idaho, where it is excavated from deep open-pit mines—a process that also unearths cadmium and radioactive thorium. Round-the-clock, the mining company uses the same amount of electricity as a city of 100,000 people in order to reduce the phosphate to food-grade quality. The caffeine is shipped from a chemical manufacturer to the syrup manufacturer in England.

The filled cans are sealed with an aluminum "pop-top" lid at the rate of fifteen hundred cans per minute, then inserted into cardboard cartons printed with matching color and promotional schemes. The cartons are made of forest pulp that may have originated anywhere from Sweden or Siberia to the old-growth, virgin forests of British Columbia that are the home of grizzly, wolverines, otters, and eagles. Palletized again, the cans are shipped to a regional distribution warehouse, and shortly thereafter to a supermarket where a typical can is purchased within three days. The consumer buys twelve ounces of the phosphate-tinged, caffeine-impregnated, caramel-flavored sugar water. Drinking the cola takes a few minutes; throwing the can away takes a second. In England, consumers discard 84 percent of all cans, which means that the overall rate of aluminum waste, after counting production losses, is 88 percent. The United States still gets three-fifths of its aluminum from virgin ore, at twenty times the energy intensity of recycled aluminum, and throws away enough aluminum to replace its entire commercial aircraft fleet every three months.


Chaz said...

Wow, interesting ideas here.
I have a dream of building a home completely out of recycled items.

GoneGreen said...

Australia, Norway, Germany, USA... all these countries involved just so that people can, as the pieces says, drink "caramel-flavoured sugar water"... that makes me not want to buy a can ever again, although I can't remember the last time I did...

I'm shocked at the figure of 84% of cans thrown away by Brits, I thought we were getting better :(