| 摘要 |
In the proposed process for pulverizing solid polydispersional materials, the latter undergo preliminary pulverization to produce particles of 5 mm in size. A conveyor gas flowing at a speed of 20 m/s is then added to the material to produce a low-velocity suspension of solid matter in gas which is then fed into the pulverization area. An energetic gas is introduced into the area, essentially at a tangent and flowing at a rate equivalent to Mach >/= 1.0. In the feed zone, the ratio of the braking pressure of the energetic gas to the static pressure at the axis of the turbulent flow is maintained at a value greater than a value determined by the function: (I), where Kj is the adiabatic curve characteristic of the energetic gas, and 1 < k </= 1.667. In addition, the static pressure of the energetic gas in the feed zone is maintained at a level lower than that of the gas phase of the high-velocity suspension formed in the pulverization area as the low-velocity suspension is accelerated by the supersonic stream of energetic gas. Around the periphery of the pulverization area, agitation zones are created, in each of which the pressure fluctuates within a range +/-(1...100)Pa relative to the pressure in the pulverization area and with a fluctuation frequency of up to 10 kHz. With the process described, it is possible to obtain a specific surface area in the pulverized and graded material of 8000-12,000 cm<2>/g, depending on its structure, with a mean particle size in the finished product of about 3 mu m. |
