Other processes

Mechanical shredding

consists of four phases called bead removal (removal of metal rings), shredding (the tire is reduced to small pieces of 70 × 70 mm), granulation (the rubber parts are separated from those in steel and fabric), micronization (the granules are cleaned and further shrunk).

MAIN DIFFERENCES

the reduction processes do not take place in a airproof environment kept in negative pressure and therefore there is a release of highly polluting particles into the air. Energy enhancement is delegated to third parties as a supply of secondary raw material, therefore the process is not self-sustaining. Finally, the powder is not completely deprived of the sulfur introduced during vulcanization, making it for the most part not completely inert.

Cryogenic processes

it is a method that consists of three steps. The first is mechanical shredding (it is a conventional shredding that reduces the pieces to be treated), then we move on to cryogenic shredding (liquid nitrogen is used to cool the material which thus assumes an easily grindable crystalline structure), pulverization (it reduces further the volume of particles).

MAIN DIFFERENCES

the reduction processes do not take place in a vacuum environment and therefore there could be release of polluting particles into the air. The cost of working with liquid nitrogen is extremely high as well as dangerous for the workers employed in the vicinity. Energy enhancement is delegated to third parties as a supply of secondary raw material, therefore the process is not self-sustaining. Finally, the powder is not completely deprived of the sulfur introduced during vulcanization, making it for the most part not completely inert.

Electrothermal processes

this method consists of four distinct phases. Mechanical shredding (the material is reduced into coarse pieces), electrothermal treatment (the pieces are introduced into vertical magnetic induction ovens; the process allows the rubber to dry and detach from the metal part; the pieces will be collected in the lower part of the oven), devulcanization (with further procedures, the rubber is returned almost to its original state).

MAIN DIFFERENCES

the reduction processes do not take place in a vacuum environment and therefore there could be release of polluting particles into the air. Extremely energy-intensive as the energy contained in the waste is not enough to reach the required temperatures but must even be taken from the outside.