Gust: Tire recycling starts at inception

HILTON HEAD, S.C.—For Dick Gust, tire recycling doesn't begin when a tire reaches the end of its life on the road.

Rather, the whole process begins when a new tire is manufactured, even before it's placed on a rim, according to the CEO of the Tire Industry Association.

"The future life, performance and recycling potential for this tire depends on the activities occurring at the time of product inception," he said during a presentation at the recent Clemson University Tire Industry Conference in Hilton Head.

Material selection and engineering of the tire help determine both a tire's current and future life. "A sustainable tire will have features built in to maximize performance and tire wear, while also containing recycled materials such as recycled carbon and fine grind recycled rubber to enhance the product's sustainability," Gust said.

From there, each step of the journey is key to an end-of-life tire (ELT) finding a successful use when taken out of service. A "responsible generator"—be it an automobile manufacturer selling a new car or a tire dealer mounting a replacement tire—will make sure the tire is properly installed and the consumer educated to get the maximum performance from the two tires.

"Responsible tire dealers provide educational materials to encourage tire maintenance," said Gust, formerly an executive at Liberty Tire Recycling L.L.C. of Pittsburgh.

Proper technician training also is vital in ensuring a new tire has maximum first life performance. And the techs also must be careful in dismounting a worn tire to maintain the potential for the tire to be used for retreading, if it's a truck tire, or have continued life as a used tire.

TIA, he added, has long taken the lead when it comes to training. "TIA really is considered the gold standard for training technicians," the association's CEO said. "Since 1997, we have trained over 180,000 tire technicians in tire dealerships."

During his presentation, he displayed a photo from a dealership that didn't take the job of preserving ELT tires seriously.

"They don't respect the raw materials very much because they leave them out in disarray. They subject them to contamination," Gust said. "This is something we have to work on as an industry to maintain that scrap tire so that we can put it through the process properly."

Instead, dealers should provide secure storage areas; protect the tires from contamination; keep them dry to prevent the spread of disease; secure the tires to prevent theft; and maintain scrap tire generator licenses.

He added, though, that the vast majority of dealers involved in ELT activity are much more professional than they were years ago.

Tire recycling is capturing the valuable materials designed into the tire, Gust said, while tire sustainability is maximizing the use of the original tire along with the raw materials in the tire.

"The professional tire recycling industry today has the infrastructure in place to collect end-of-life tires from tire generators, and the equipment and technologies necessary to process that tire into components and recycled products," he said. "The industry today is much more professional than it was years ago and they're moving toward sustainability."

While yields vary greatly depending on what type of tire it is—from passenger all the way up to OTR units—Gust said a typical passenger tire weighing 25 pounds would yield:

• About 70 percent rubber, or 17 pounds;
• 15 percent high-quality steel, or 4 pounds;
• 3 percent of fabric, or 1 pound; and
• 12 percent, or 3 pounds, of other materials such as silica or carbon black.

Looking at the scrap tire markets, Gust said Liberty Tire Recycling data found the vast majority of the tires go to tire-derived fuel (TDF), at 43.5 percent. That is followed by mulch and civil engineering chips, both just over 17 percent; re-use as tires at nearly 9 percent; crumb rubber at 8.7 percent; and wire extraction at 4.4 percent.

TDF is mixed with coal and other fuels and is burned in cement kilns, power plants, paper mills and industrial boilers. It's also a use that the industry wants to see utilized less in the future.

"In the recycling community, what we're trying to do is lessen the size of that pile that's used in tire-derived fuel and move it more into the crumb rubber. Move it up the value chain of using raw materials rather than just as TDF," Gust said. "We look at (TDF) more as resource reduction than recycling, but it's an element we need today to consume those scrap tires.

Looking at some of the other uses, he said civil engineering with tire-derived aggregate is a usage that has grown in stature over the years. It's used as lightweight fill for embankments and subgrade insulation for roads, among other uses.

Rubber mulch generally is used more in commercial applications rather than private properties, with bags of the product available at a wide variety of retail locations.

Crumb rubber is used in a variety of products, including rubberized asphalt for paving projects, hoses, auto parts, flooring and other applications, including some designed into new tires.

"Crumb rubber is something that hopefully will take over for TDF in the near future," Gust said.

The steel wire material is high carbon steel that is sent to smelters for processing and reused in such products as home appliances, automotive manufacturing, building construction, and water and fuel tanks, according to the TIA CEO.

He specifically noted that rubberized asphalt has made improvements in technology over the past few decades. There are new methods for combining ground tire rubber with asphalt; the cost of modified asphalt mixes with rubber have significantly reduced in cost; and it allows for the use of thinner, low-cost rubber pavements for light duty roads.

And the "dry process" rubber asphalt handles like regular hot mix asphalt, Gust said, but the modified pavement is more resistant to rutting and cracking.

"Rubber modified asphalt can be recycled back into another road. So it truly is a sustainable product," he said.

There also are emerging technologies that are becoming commercialized that will improve the quality and economics of recovering the raw materials in the tire. "When this happens, current recycled rubber end uses benefit, and the use of recycled material in tire production and other products will increase," Gust aid.

These include micronization, where liquid nitrogen freezes rubber to its "embrittlement temperature" and mechanical shearing is used to convert the particles to powder. In addition, devulcanization breaks the sulfur-to-sulfur and sulfur-to-carbon bonds between the polymer chains, leaving rubber particles.

Pyrolysis, or heating whole or shredded tires, is bringing companies in the business to open the door for easier carbon black recycling, with the benefit of steel and oil production, he said.

"The days of tires becoming an environmental problem are coming to an end," Gust said. "Better solutions are being developed to capture the high-quality steel and to recover the valuable raw materials designed into the tire. Instead of tire dumps and landfills, we see roads, playgrounds, rubber products, sporting fields and, yes, materials designed into new tires."