gopalakrishna

Steel and aluminum are both mined from ores, and are made in a similar way. The essential ingredient in steel making is iron ore. Iron ore is plentiful, but we cannot use it as it occurs in nature. Iron is usually combined with oxygen, or with other elements, like carbon and sulfur. We must smelt the iron ore—strip or reduce it of its oxygen—to get to the iron.

It takes a great deal of energy to reduce iron oxides. An oxide is a compound with oxygen and some other element. The reduction takes place in a very hot blast furnace. A chemical reaction takes place in the blast furnace, and the iron is freed from the oxygen. This free iron (called pig iron by steel makers because it forms a pattern that looks like tiny piglets surrounding their mother) is used to make steel.

Steel recycling saves a lot of energy. It is much more energy efficient to use steel scrap to make new steel than to mine the iron ore and then smelt it in a blast furnace. It takes about 60 percent less energy to make steel from recycled materials than it does from iron ore. That’s why today’s steel makers always use some steel scrap to make new steel products.

Steel is probably the easiest material to separate from the rest of the solid waste stream. Steel is attracted to magnets, so special magnetic belts can be used to separate steel cans from other recyclables. This is a much more efficient method than the labor-intensive hand-sorting necessary with other recyclables, such as plastics.

Recycling your used steel cans at home is easy, too. All you need to do is rinse the food from the cans. That’s it. Years ago, scrap dealers asked people to remove the paper labels and the tops and bottoms from cans. This is no longer necessary.

If you’re not sure which cans are steel and which are aluminum, use a magnet to separate them. Steel will stick to the magnet; aluminum will not. If you come across a can with a steel body and an aluminum top—called a bimetal can—put the can with the steel recyclables. Steel recyclers can accept all types of steel cans, even those containing aluminum. Aluminum recyclers can only accept 100 percent aluminum cans.

After steel scrap is collected from homes, recycling centers, or waste-to-energy plants, it is shipped to one of the companies that buy old steel—steel mills, iron and steel foundries, scrap dealers, and detinners. Detinners remove the layer of tin from old steel cans. This tin is valuable and can be sold.

Steel can recycling follows almost the same process as aluminum can recycling. Steel cans, along with other steel scrap, are melted in a furnace and then poured into casters that continuously roll and flatten the steel into sheets. Recycled steel cans can be made into new cars, girders for buildings, or new food cans. In the U.S., steel cans and other steel products contain at least 25 percent recycled steel, with some containing nearly 100 percent recycled steel.

Like aluminum, steel can also be recycled again and again. It does not lose any of its strength or quality in the recycling process. It can be a never-ending process that continues to save energy and resources.