| 摘要 |
The invention relates to a process and apparatus for the continuous dry granulation of powdered carbon black. Granulation is performed with the assistance of a toothed-shaft granulator which has, in a circular, cylindrical, drum-shaped stator with a longitudinal axis, an axially-arranged toothed shaft which rotates about the longitudinal axis of the stator and conveys the powdered carbon black from the inlet to the exit of the granulator, with simultaneous granulation. The teeth have a diameter and a length, and are arranged on the shaft axially-offset with respect to each other along a helical line around the shaft. The maximum peripheral speed of the ends of the teeth is between 1 and 6 m/s, and the average residence time for the carbon black in the granulator is between 20 and 600 seconds. Perferrably, the axial distance between neighbouring teeth is less than their diameter so that complete covering is provided by the teeth along the axis, and the length of the teeth is selected so that the clear space between the ends of the teeth and the stator wall is 0.5 to 3 mm. It is advantageous to have the teeth arranged on the shaft along two or more helical lines. This means that, for comparably-sized equipment, the carbon black throughput can be increased several times as compared with pelletising drums used in a conventional manner. |
