Few things are more unsightly than a pile of discarded tires. Unfortunately, America has quite a few such piles. There are about 3 billion abandoned tires in the U.S., with another 200 million being added each year.
Aside from their lack of aesthetic appeal, abandoned tires are a potential fire and health hazard. Tire piles are a breeding ground for disease-carrying mosquitos and rodents. Tire pile fires give off a choking black smoke and a greasy ooze that can pollute the surrounding land and water. Such fires–which may start from vandalism or from heat and pressure from deep inside the pile–can take weeks to put out.
Tires are also unwelcome guests at landfills, where they tend to work their way to the surface and “pop out” after several years. Efforts by some states to charge a hefty disposal fee for old tires have led, predictably, to widespread illegal dumping of the unloved objects. As a result, many states and counties are looking for viable commercial uses for old tires.
Cement kiln recycling technology may be just the answer they’re after.
The Cement Kiln Recycling Coalition (CKRC) is a group of companies that together promote the safe recovery of energy from waste materials in the cement manufacturing process. These days, ugly, smelly, discarded tires are at the center of the CKRC’s attention.
Some tires can be “recapped” and reused. Some are recycled as an asphalt additive. Some are used as a supplemental fuel in power plants and paper mills. And, increasingly, old tires are being used as a clean fuel for making cement.
If you’ve ever had the misfortune of smelling rubber burning in an open fire, you may find it difficult to imagine that tires can be burned cleanly. But in cement kilns–brick-lined furnaces up to 25 feet across, several hundred feet long, reaching temperatures over 2,700 degrees Fahrenheit–tires burn completely and produce no smoke. Limestone fed into the kilns to make cement acts as a natural pollution-control device, neutralizing acid gases and trapping other pollutants.
Cement kiln recycling boasts an astonishing environmental record. A single cement kiln can use up to 2 million scrap tires a year, saving more than two gallons of oil or 25 pounds of coal for each single tire burned. Combined, the nation’s dozens of operating cement kilns are estimated to be using 100 million tires a year–solving one-half of America’s scrap tire problem.