Tire recycling and reuse efforts have come a long way over the years. Consider the fact that an estimated 1 billion scrap tires could be found in U.S. stockpiles in 1990. Today, that number isn’t in the billions, but the millions – 67 million to be exact. It’s significantly less, but there’s still work to be done when it comes to tire recycling and reuse, especially when you consider that about 300 million tires are discarded in the U.S. each year.
Why is it a challenge to recycle and reuse tires? It’s largely because of their vulcanized-hardened rubber makeup. Rubber can be devulcanized, but it’s expensive and thereby easier to just take used tires to stockpiles, landfills or burn them. Not only can tires fill up stockpiles and landfills, but their byproducts can also potentially leach into the soil, which makes discarding them via these methods problematic. What’s more is that they can serve as a breeding ground for mosquitoes, another concern as mosquito-born diseases have gained traction domestically over the years.
The good news is that there’s arguably more promise for tire recycling today than there ever has been before. Here’s a look at some of the latest recycling technologies that are poised to help that 67 million number get closer to zero in the coming months and years:
The Latest Tire Recycling Technologies
- Cryogenic freezing: Researchers at Lehigh Technologies have developed a tire recycling method that uses liquid nitrogen to freeze chunks of shredded tire to temperatures of -100 degrees Celsius. After these tire chunks are frozen, they’re fed through a high-speed mill that essentially shatters them into tiny, fine powder particles about 180 microns in size. The fine powder afterproduct enables the material to more easily bond to other materials for reuse. For instance, these fine powders can actually be used to create brand new tires, among other products.
- Renewable tires: A recent initiative from researchers at the University of Minnesota isn’t so much about tire recycling as it is about tire production. Case in point: The research team has developed a technology to produce tires from grass and trees – not conventional rubber and fossil fuel. Specifically, the process creates isoprene, one of the key ingredients in car tires. It is created via microbial fermentation of sugars, then reacted with hydrogen to create the methyl-THF chemical. The methyl-THF chemical is then dehydrated using a newly discovered catalyst, thereby eventually creating the isoprene molecule. The process has the potential to take fossil fuels out of the production process, which thereby makes tire manufacturing more sustainable.
- No more metal contamination: Australian-based companies CSIRO and VR TEK note that one of the major inhibitors of tire recycling is the potential for metal contamination in recycled byproducts. However, the duo has recently developed a three-step process to help prevent this from occurring. The technology essentially works to separate tires into sections based on material composition. This differs from the more widely used practice of tire shredding. The two companies believe their initiative could help improve tire recycling by about 50 percent.
- Pyrolysis: Used tires being converted into energy is another process gaining momentum. Specifically, it consists of shredding tires down and inserting the shredded chips into a pyrolysis system. Pyrolysis is the act of heating without the presence of oxygen, meaning that there’s no combustion. With tires, this means they can be heated to high temperatures of 450 degrees Celsius without actually burning. This, in turn, breaks down gases and solids, eventually creating low-sulfur diesel fuels. Pyrolysis is currently the recycling method of choice at Texas-based Global Clean Energy Inc.
Whenever there’s a problem that needs to be solved, innovation and creative thinking can help lead to a solution. When it comes to tire recycling, the days of tires ending up in stockpiles or landfills could be numbered. For more information on tire recycling technologies, contact us today.