Recycling of Waste Tires and Its Applications

Vehicles and airplane tires are produced in massive volumes all around the world. Once a tire reaches its end of life, it needs to be replaced. Dumping waste tires create a major environmental challenge as tires have a complex structure and are not naturally degradable in the environment. Dumping tires in landfill can threaten the environment by toxifying soil and water and releasing emissions into the air, creating a health hazard to human and ecological receptors. In addition, carbon is released into the air when a pile of tires fires, exacerbating the ongoing challenge of global warming and climate change. Thus, effective actions to address waste tires are important for the environment and human health. Recycling waste tires has been investigated as an environmentally friendly alternative to dumping old tires. Rubber chips, rubber crumbs, rubber powder, wire, and nylon wire are valuable components of scrap tires. Shredding tires and tire pyrolysis are the best methods for recycling waste tires and taking advantage of their components. This paper provides an overview of these two recycling methods and compares them. These methods are clean and environmentally friendly. Both methods can preserve the environment along with being profitable. The products of the shredding tire can be used in industry and construction. For example, crumb rubber is substituted with a part of aggregates in concrete, and it can be used as artificial turf in stadiums, bumpers, soil conditioners, asphalt rubber, playgrounds for recreational areas, etc. Furthermore, the pyrolysis reactor heats the tires and decomposes their basic materials enabling the extraction of oil and gas. However, in comparison with shredding tires, the pyrolysis process requires specialized expertise as extracted products are greatly affected by the temperature, particle size, duration of heating, chemical admixture, and atmospheric pressure.