| Ambient (0.3 mm rough, irregular) |
Repeated grinding following shredder, mills, knife, granulators, and rolling mills |
High surface area and volume ratio |
Temperature could rise up to 130 °C |
| Oxidation on the surface of granulates |
| Cooling needed to prevent combustion |
| Wet ambient (100 μm rough, irregular) |
Grinding suspension of shredded rubber using grindstone |
Lower level of degradation on granulates |
Requires drying step and shredding of tires before grinding |
| Water cools granulates and grindstone |
High surface area and volume |
| Water jet (rough, irregular) |
Used for large sized tires (trucks and tractors) |
Environmentally safe, energy saving, low level of noise, and no pollutants |
Requires high pressure and trained personnel |
| Water jet of >2000 bar pressure and high velocity used to strip rubber |
| Berstoff’s method (rough, irregular) |
Combines a rolling mill with a specially designed twin screw extruder in a line. |
Small grain size, large specific area, and low humidity |
Not disclosed |
| Cryogenic (75 μm sharp edge flat/smooth) |
Rubber cooled in liquid nitrogen and shattered using impact type mill |
No surface oxidation of granulates and cleaner granulates |
High cost of liquid nitrogen |
| High humidity of granulates |
