Circular Rubber Technologies and Entex announce joint program devulcanizing end of life mining tires

Vancouver, Canada – Circular Rubber Technologies (CRT) is a Vancouver, Canada, based start-up developing a circular solution for end of life mining tires. CRT offers a full-service solution for one of the mining companies’ largest waste streams, while providing the tire manufacturers with a consistent source of rubber reclaim.

ENTEX is an innovation and development cradle, the world market leader in extrusion technology and process engineering with the Planetary Roller Extruder (PRE), having received more than 135 patents, property rights and utility models. ENTEX supplies PRE’s to many different industries.

Through a joint testing program, CRT and ENTEX have proven that devulcanizing end of life mining tires with the PRE is possible and provides a high end reclaim material suitable for reuse by the tire manufacturers.

Recycling of end of life tires has been on the agenda for a long time. Focus to date has been on applications which downgrade the material, either for the use of rubber products or through energy recovery and pyrolysis. To reuse the rubber polymers from vulcanized rubber products requires the conversion of vulcanized rubber back into a devulcanized elastomer. The properties of reclaim devulcanized with the Planetary Roller Extruder are expected to exceed those of reclaim devulcanized by other methods.

The PRE devulcanizes end of life mining tires that are first shredded to granulate in a continuous process. The modular system of the ENTEX extruder allows the flexibility to optimize the set up for the specific application. Also, the further development of the applied materials, overall design and improved thermodynamic process control provide capabilities and versatility superior to other extrusion systems and are required for devulcanizing natural rubber.

Devulcanization of (natural) rubber reverses the vulcanization process. During devulcanization of rubber granulate with the Planetary Roller Extruder, the sulfur bonds in the rubber granulate are broken by thermo-mechanical stress, separating the sulfur from the elastomers. A high-quality rubber reclaim has a low degree of crosslinking between existing rubber-elastic materials. In the ENTEX patented Planetary Roller Extruder, the temperature/pressure profile of the extrudate in the processing section of the extruder has a decisive influence on the devulcanization quality.

Controlled temperature combined with mechanical stress devulcanizes the material without breaking the carbon chains of the elastomers, thus not damaging the sensitive natural rubber.

The production tests have shown the value and feasibility of the proven ENTEX Developed De-Vulcanization process for this specific application as well as CRT’s proprietary process for the use of reclaimed material from giant off road mining tires.