Tire Recycling

Tire recycling involves reusing waste tires or end-of-life tires (ELT) that are no longer acceptable for use on vehicles due to irreparable damage or wear. Tire recycling technology is utilized for this process.

Definition End of Life Tire (ELT): A tire that can no longer serve its original purpose on a vehicle. This excludes used tires reused, retreaded, or exported in used cars.

Landfill disposal of waste tires

Landfill disposal of waste tires presents serious environmental concerns. Part of the risk lies with the chemical makeup of tires. Toxins released from tire decomposition, incineration, or accidental fires can pollute the soil, air, and water.

The tire recycling industry is very divided and under stress due to increasingly stringent legislation. Although the tire recycling industry is growing steadily and it’s important to recycle waste tires, they are very challenging to break down.

Rubber tire recycling

Rubber tire recycling is the processing of tires dumped in landfills and end-of-life tires into materials reusable for new products. When the functionality of tires decreases due to wear or damage and are not easily reparable, tires are considered end-of-life and are suitable for recycling.

When recycling rubber products, you can reuse the ground rubber that you get after shredding waste tires or use the waste tires as fuel either by burning them or making fuel out of them using pyrolysis. Reusing the ground rubber is the most environmentally friendly way of recycling tires since almost all the rubber is reused.

Failure to recycle waste tires is a missed opportunity to produce the useful secondary raw material. In certain applications, ground rubber has unique properties that are superior to traditional materials:

• Shock absorption
• Sound absorption
• Non-slip
• Lightweight
• Permeable
• Insulating
• Abrasion and crack resistant

There are a lot of tire recycling processes that can be used to recycle waste tires. Tires can be recycled into rubber and steel wires that can be reused or the tires can be recycled using Tire pyrolysis and used as fuel.

Steel wire removing

Tires have steel wires int them to help with resistance. The steel wires need to be removed before the tires can be recycled. The steel wires can be reused for new steel goods and the rubber moves on to the next step in the recycling process.

Whole tire processing

After removing the wires, the rubber tires need to be reduced in size. There are two ways to reduce the size of the tires:

1. Mechanical – A shredder is used to reduce the rubber into smaller pieces, the size of the pieces can be regulated using a granulator.
2. Cryogenic – The tires are frozen with liquid nitrogen. The frozen tires are then smashed to smaller pieces with a hammer mill. All left over steel pieces can be removed with a strong magnet and other materials can be removed with an air classifier.

Screening

At this point in the process all of the rubber is screened and all steel and other fibers that affect the usability of the rubber are removed. During the screening process the rubber is also sorted by the size of the particle and any pieces that are too big are removed.

Cleaning

At this stage, the screened rubber is cleaned using water or other cleaning substances. The rubber can now be used as raw material. Examples of uses of the rubber are in rubber shoes and playground turfs.

Tire pyrolysis

Pyrolysis is a recycling method whereby whole or shredded tires are heated in an oxygen-free reactor. The rubber gets softened and the polymers start breaking down into smaller molecules. These molecules then gasify and leave the reactor.

The gasses can be either burned directly to generate power or condensed into a fluid that can be used as fuel. Not all molecules can be condensed but these smaller molecules can be used as a fuel. Not all parts of the tire can be used for fuel, after the pyrolysis process about 40% (by weight) of the tires can be removed as ashes.

Examples of manufacturers for turnkey tire recycling systems are CM Shredders, Eldan Recycling A/S, Fornnax, Eco Green Equipment, and many more.

Tire-derived products (TDP)

Tires are primarily burned for their fuel value but can also be processed into other tire-derived products.

Examples of other tire-derived products are:

• Construction materials,
• Industrial feedstock,
• Ground and crumb rubber for rubberized asphalt,
• Tire-derived aggregate.

Tire recycling innovations continue to be of significant importance as the need for new sustainable, circular end-use markets.

Recent tire recycling innovations include:

Genan  takes in all types of tires – from cars, vans and trucks – and in a highly technological production process separates them into their original elements: rubber, steel and textile fibers. The output consists of 75 percent rubber powder and granulate, 15 percent steel and 10 percent textile fibers.

Australian tire recycler Green Distillation Technologies (GDT) partnered with CarbonScape, a company based in New Zealand, to turn the carbon created in its recycling process into high value graphite.

Wastefront, a rubber waste recycling company, converts disused tyres into useful commodities, including liquid hydrocarbons and carbon black, which can then be reutilised in processes such as alternative fuel manufacturing or ground rubber production.

Danish manufacturer of tyre recycling equipment, ELDAN Recycling A/S, has developed a new sensor-based system to detect foreign objects in tyre shreds and reduce the risk of breakdowns and yearly down time.

Projected to solve a big issue in the mining field, the HYPERTYM™ integrated mobile unit reduces of all OTR mining tires and all oversized tires up to 63”, allowing for easy recycling and disposal of used tires.

The unique Pyrum-Thermolysis is a thermal dismantling of organic substances respectively rubber and plastic waste under exclusion of oxygen.

RubberJet Valley is a chemical specialty company specialized in the production of engineered raw materials (Polymers) called RubberJet Powder (RJP ™) and RubberJet Granules (RJG ™) capable of replacing virgin raw materials (for example Natural Rubber) in a wide range of applications including which mixes new tires.