Although used tires are a complex and challenging form of solid waste, the demand for scrap tires has been soaring over the years due to the booming scrap tire recycling industry. The tires that motorists are driving on the road can be shredded and burned to generate fuel oil, used to make fuel, or pulverised to bits to be used to fill in a playground or football field.
Tire recycling or rubber recycling involves the use of tires that can no longer be used by vehicles owing to significant wear and tear. The high availability, bulk, resilience and non-biodegradability of the tires make the scrap tire recycling business lucrative. Besides, with more than half a million tires being disposed annually, recycling is a great way of reducing landfills in addition to being a profitable venture. So then, what does the process of tire recycling entail?
Process of Tire Recycling
- Collection of Used or Worn Out Tires
Just like any other recycling process, collection is the first step. This function may be assigned to individuals or business individuals that are paid to collect the scrap tires and send them to the collection points. Once the required volume is reached, they are packed on trucks and sent to the processing plants.
- Whole Tire Processing
Once the tires reach the processing plant, they are cut into tiny pieces. This step is important as it is aimed at reducing the volume of tires while also creating materials that are easy to handle. Tire shredders that are specially designed with two counter-rotating shafts that are used to cut the tires into 2-inch pieces. Generally, the end product from this stage may be used as raw material for fuel that is tire-derived. Tire processing involves two systems:
- Mechanical Systems
These are used to grind the scrap tires into small chips through an ambient process. The size of the product is determined in a typical ambient system where the rubber shreds are put in the granulator that is fitted with screens.
- Cryogenic Systems
Here, the tires are frozen at low temperatures, shattering the rubber and effectively creating different sizes. Liquid nitrogen is then used to super cool the tire shreds. The rubber that is extremely cold and brittle is then passed through a hammer mill that shatters it into tiny particles. Magnets are then used to remove steel while fibers are separated with the aid of air classifiers. The clean recycled rubber is then used in other applications.
- Mechanical Systems
- Steel Liberation Stages
This entails processing and preparing the tire shreds that are obtained in stage 1 for elimination and separation of the tire wire from rubber that are usually used for strength, versatility and resilience. It also includes course screening and fiber separation. The wires are sent to the rolling mills to manufacture new steel while the rubber mulch may be used as filed or playground turf.
- Screening and Milling Stage
Here, the rubber is carefully observed to ensure that there are no wires or other forms of contamination. Screening involves a huge number of varied sizes of rubber that contain no wires to sort them according to sizes while eliminating substances that are unwanted. Unwanted and extra-large rubber pieces are also reduced here.
- Cleaning Stage
When the screening is completed, the rubber that is obtained is thoroughly cleaned using water and other cleaning agents. The clean rubber is then packed and transported to other factories that need rubber as a raw material such as manufacturers of rubber shoes and playgrounds among others.
Impact on Environment and Health
- Environmental Concerns
Tires pose a health risk to people and the environment. When put in waterlogged ground, tires are able to leach toxins into underground water, posing a huge problem.
- Health Concerns
Tires that are used and dumped pose a health problem to people. Small animals and insects that use tires as their homes may also cause the human population some serious health issues. For instance, mosquitoes may breed in water that is lodged in tires and later cause health problems to people.
In conclusion, the importance of recycling tires cannot be overemphasized as this is not only keeping the environment clean but also promoting good health by preventing the possible spread of diseases.