How2Day: Tire Recycling Methods

Several methods are used to recycle old tires. Peter Starman/Photodisc/Getty Images
Tires are difficult to recycle, because they can't just be melted down and reused. This is mainly because tire rubber is treated during a process called vulcanization. The process makes tires much more durable and resilient for safe riding, but it also makes recycling them much more difficult. Luckily, there are several methods available to make use of the millions of scrap tires in stockpiles throughout the country.

Tire recycling methods often involve mechanical breakdown. This means that the tires are shredded into small pieces, and then the steel fibers are removed. The leftover grounded rubber material can be used in several civil engineering applications. For example, many running tracks and even playground floors are made from shredded rubber, providing a softer, more shock-absorbent running surface.

Whole tires can also be reused. Many racetracks use old tires as a crash barrier in case a car hits a wall, and marinas may use them as boat bumpers. The use of whole tires is rather minimal, however, compared to the percentage of tires that are mechanically broken down.

Old, worn tires are often retreaded. The tread of the tire is the part that makes contact with the road. The process of retreading replaces the old, worn tread with a new one. According to the Environmental Protection Agency (EPA), retreading an old tire uses 70 percent less oil than producing a new tire. It is also 30 percent to 70 percent cheaper in cost per tire. These tires provide the same quality and safety as new tires.

Pyrolysis is a newer technique for tire recycling, in which tires are heated in an oxygen-free environment. This breaks down the tires into oil, steel, and carbon black. Carbon black is a valuable ingredient in tires and other rubber and plastic products, and it can also be used in printer toner cartridges. Pyrolysis is still being tested for commercial use, but is a promising technique.

How2Day