Tire Composition and Recycling Methods
Have you ever wondered about the internal structure of tires, where used tires end up, and what recycling methods are available? If so, let’s explore this together.
Tire Composition
To understand the recycling value of tires, we must first understand what tires are actually made of. If you cut a tire open, you’ll find that it’s not just a simple lump of rubber, but a composite of multiple materials.
Rubber (Approx. 50%)
Tires are primarily composed of two types of rubber:
Natural rubber: derived from the sap of rubber trees, it has good elasticity, ensuring grip and comfort.
Synthetic rubber: made from petroleum, it is wear-resistant and heat-resistant, suitable for high-speed driving.
Carbon Black (Approx. 25%)
Although carbon black is just a black powder, it plays a vital role. It makes tires more durable and resistant to wear—like adding steel bars to cement. Without it, tires would be ruined after only a few hundred kilometers.
Reinforcing Materials (Approx. 15%)
This section includes steel wire and fiber cord:
Steel wire: Primarily used in heavy-duty tires for trucks, buses, etc., to bear the weight of the vehicle and withstand impact forces.
Polyester fiber and nylon: Used in passenger car tires to ensure the tire maintains its shape stability during high-speed rotation.
Additives (Approx. 10%)
It contains sulfur and antioxidants. Sulfur makes the rubber tougher and prevents it from becoming soft and limp; antioxidants prevent tires from aging and cracking prematurely.
Four Core Recycling Methods
Once tires are collected, how can their value be maximized? Currently, there are four main recycling methods.
Method 1: Retreading
♻️Target Audience
Tires with intact carcasses and only worn treads, primarily for heavy-duty tires on large trucks and buses.
♻️Process Flow:
Inspect tire carcass → Grind worn tread → Apply new tread compound → Re-curing
✅Advantages
Cost is only one-third to one-half that of a new tire, with the highest resource utilization rate, and is the internationally recognized preferred path for tire weight reduction.
Method 2: Producing Reclaimed Rubber
♻️Process Flow:
Crushing: Waste tires undergo crushing and other pre-processing to become fine rubber powder.
Desulfurization: The rubber powder is pneumatically conveyed and precisely mixed, completing the desulfurization process in a closed environment under normal temperature and pressure.
Molding: The desulfurized recycled rubber exits the production line, where it is then cut, coated, and stacked.
Method 3: Producing Rubber Powder
♻️Process Flow:
Waste tires → Mechanical crushing → Grinding into rubber powder of different fineness → Removal of steel wires and fibers → Finished rubber powder
Method 4: Pyrolysis
♻️Process Flow:
Pretreatment: Waste tires are trimmed, steel wires removed, and then crushed into rubber particles of approximately 1-2 mm.
Thermochemical Pyrolysis: The rubber particles are placed in a high-temperature environment of over 420 degrees Celsius for about 1 hour. In an anaerobic environment, thermal energy is used to break down the high-molecular-weight substances into low-molecular-weight substances.
Product Separation: The pyrolysis products are collected separately.
One tire can produce:
Primary oil: approximately 38%
Carbon black: approximately 33%
Steel wire: approximately 20%
Combustible gas: approximately 9%
From refurbishing and making recycled rubber to grinding into rubber powder and extracting oil and carbon black through pyrolysis—each of these methods has its own uses and can turn waste tires into valuable resources. Moreover, the technology is becoming more and more mature, the processing efficiency is higher, and the pollution is getting smaller and smaller.
If you’re considering a tire recycling project, Gomine is a great option. No matter which recycling method you choose, we have the right machines for you. Feel free to contact us anytime!
