Several factors weigh in favor of recycling aluminum. It doesn't deteriorate and can be recycled indefinitely with no loss in quality. According to the U.S. Energy Information Administration, recycling aluminum takes 95 percent less energy than refining it from ore. Once you have a quantity of recycled aluminum, you need only melt it and re-form it into new products. Recyclers have developed automated processes to separate aluminum from plastic, glass, and other materials.
Collection
According to Earth911, a company that specializes in recycling and reuse, aluminum can recycling begins as waste haulers pick up and organize materials headed for recycling centers. Scrap aluminum comes from many sources, including beverage cans, junked cars, and home remodeling. Scrap dealers and municipalities collect many different kinds of trash, some mixed, some with the aluminum already sorted out.
Separation
If the recycler handles mixed trash, its equipment or staff must first separate plastic, glass, and metals into separate streams. According to a recycling manual developed by the Environmental Protection Agency (EPA), a waste stream tumbles from a conveyor, falling past separators. A device called a magnetic separator pulls out ferrous (iron-bearing) metals like steel with powerful magnets. An eddy current separator works in a similar fashion, but produces repulsive magnetic forces that fling the falling aluminum pieces away into a bin.
Size Reduction
Aluminum scrap comes in many forms, like cans and window frames, that occupy space, so the recycler squeezes them into a more compact, efficient form. Then a machine cuts the aluminum cans into chips under an inch in size. The chips accumulate into a pile that's denser than the original items, reducing volume and subsequent transportation costs.
Melting and Casting
The aluminum-processing factories called smelters heat the chips to burn off any printed material, then melt them, blending the recycled material with newly-refined, virgin aluminum. The smelter pours the molten aluminum into molds, forming 25-foot ingots weighing over 15 tons.
Milling
Rolling mills process the aluminum ingots into sheets of varying thickness. The mills press the ingots between giant steel drums, flattening and stretching the aluminum in stages. For beverage cans, the sheets are about the thickness of a human hair. After squeezing the ingots into sheets, the mills roll them into coils and ship them to manufacturers, who turn them into products such as soda cans, siding, and car parts.
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