About Tire Rubber Recycling

December 16, 2021

The rubber industry is one of the important basic industries of the national economy. Rubber products have been widely used in every area of life, and various tires are the most common in rubber products. According to China’s rubber products industry data in 2020, tires account for more than 50% of the rubber products industry.

In 2020, under the influence of the COVID19 epidemic, total global tire sales have declined compared to 2019, but the total number still exceed 1.5 billion.

Now, let’s learn more about tire rubber recycling.

What is tire rubber

As the name implies, tire rubber refers to the rubber material used in tires.

The main material of automobile tires is rubber. The proportion of rubber in tires exceeds 50%. Its types include natural rubber, butadiene rubber, styrene butadiene rubber, butyl rubber and so on.

Different raw materials affect the key performance of tires. For example, tires made of solution polymerized styrene butadiene rubber (SSBR) have the following advantages:

Excellent wear resistance
Resistance to tread pattern groove cracking performance
High resilience
Heat resistance and good flexibility resistance after prolonged exposure at high temperature
Strong grip on wet and slippery roads

Why need to recycle tire rubber

Rubber recycling is synonymous with waste tire recycling, because used tires are by far the most common source of waste rubber. As more and more waste tires are produced, if they are not recycled or treated in a harmless manner, they will not only cause serious pollution to the environment, but also a waste of resources.

Reduce environmental pollution

If so many waste tires are simply piled up and landfilled, the waste tires are not degradable, which will cause serious and continuous environmental pollution. In addition, the flammability of rubber will cause a large amount of accumulation and cause fires, and finally cause pollution of air, water and soil resources.

Reduce waste of resources

Recycling can greatly increase the utilization rate of existing rubber resources. The production of natural rubber or synthetic rubber requires the use of a large amount of energy.

Reduce carbon emissions

The process of using recycled materials to manufacture new products consumes less energy, thereby reducing greenhouse gas emissions, mainly by reducing carbon dioxide emissions. It is very helpful for building a greener world.

Application of recycled rubber

Reclaimed rubber is made from vulcanized corner waste in the production of rubber products. It has a certain degree of plasticity and can be reused. The main purpose of reclaimed rubber is to replace part of natural rubber and reduce the amount of natural rubber used in rubber products. It can also be used alone for some low-grade rubber products.

Mainly used in the following products:

Playground ground / Athletics track
Artificial turf
Anti-slip mat / car mat
Shock cushion / shock absorber belt / parking block
Other

How to recycle tires

The main components of tires include: rubber, carbon black and frame materials. Through reasonable recycling, the use efficiency of resources can be greatly improved.

The main forms of recycling waste tires include: retreading tires, producing reclaimed rubber, rubber powder, heat energy utilization, thermal decomposition and oil refining, and use as paving materials.

Retread tires

Tyre retreading is the most effective, direct and economical way of using it directly. In the case of good use and maintenance, a tire can be retreaded many times, so that the total retread life can often reach 1-2 times of the new tire, and the raw materials consumed are only 15%-30% of the new tire. In the past, it has generally attached great importance to tire retreading.

At present, the most advanced tire retreading technology in the world is the pre-vulcanized retreading method, also known as the cold tumbling method, that is, the vulcanized tread rubber is bonded to the polished carcass, and the inflatable inner tube and envelope are installed. Sent into a large vulcanizing tank, vulcanized at a lower temperature and pressure, and can produce multiple retreaded tires at a time.

Convert waste rubber into rubber pellets / powder

Through a certain process, waste rubber is made into rubber particles, rubber powder and other reclaimed rubber raw materials, and then rubber particles, rubber powder, etc. are used as raw materials to make new rubber products for reuse.

For example, waste rubber can be cut, crushed, and desulfurized to make recycled rubber material, which can then be compounded or mixed with new rubber raw materials.

Rubber concrete

The application of rubber concrete is a possible and effective way to solve the “black pollution” of waste rubber.

Rubber concrete is a new type of environmentally friendly civil engineering composite material. Rubber is mixed into ordinary concrete to achieve the purpose of recycling waste rubber and turning waste into treasure. In the application of rubber concrete, rubber powder is usually substituted for part of the fine aggregate or rubber particles are substituted for part of the coarse aggregate.

According to related studies, rubber concrete has good shrinkage, impact resistance and fatigue resistance compared with ordinary concrete. At present, there are many applications of rubber concrete in pavement projects, such as parking lots, tennis courts and building foundations.

As an asphalt modifier

In road engineering, using waste rubber and plastics for asphalt modification can not only improve the performance of asphalt and prolong the service life of asphalt pavements, but also provides a reasonable way for the use of waste rubber.

Cracking recovery

At present, the cracking technology of waste rubber mainly focuses on thermal cracking, vacuum cracking, and catalytic cracking under an inert atmosphere.

For example, through the thermal cracking recovery process, three types of recovery products can be obtained: gas, liquid, and solid.

The gas obtained by thermal cracking can be used as fuel; the liquid product can be purified by a certain separation technology for the second time to prepare gasoline and other fuels; solid products It is a carbon material that can be used to produce carbon black and can be used as a carbon electrode material.

Fuel utilization

Waste tires are a kind of high calorific value material, and its combustion heat is about 33MJ/kg, which is equivalent to high-quality coal and can be used as fuel instead of coal. Using waste tires as fuel, direct combustion was previously used, which would cause air pollution.

At present, the burning and utilization of waste tires are mainly used for roasting cement, thermal power generation and participating in the production of solid waste fuel.

Among them, roasting cement is a recycling method with a high utilization rate of waste tires: during the cement roasting process, steel wire turns into iron oxide, sulfur turns into gypsum, and all fuel residues become the raw material of cement, which does not affect the quality of cement. It will not produce black smoke, odor, and no secondary pollution. It is reported that 50% of waste tires used as fuel in Japan are used for roasting cement.

The reasonable recycling and utilization of waste rubber can not only solve the environmental pollution problem caused by the waste of waste rubber, enable the recycling of rubber resources and petroleum resources, but also promote the sustainable development of global resources, which is of great significance.

What can USEON do

We have advantaged twin screw extruders. We can do Devulcanization and Compounding, by using recycled tire powder, PP and Paraffinic oil according to a reasonable formula, and finally produce high-quality TPE materials.