The influence of pressure and temperature on inert gas jet mill
The main factors affecting the crushing effect of the jet mill:
- Pressure
The pressure of the working fluid is the main parameter that produces the jet flow velocity, and it is also the main parameter that affects the pulverization fineness. The kinetic energy of the working fluid jet is proportional to the first power of its mass and the square of its speed. Therefore, the higher the pressure and the faster the speed, the greater the kinetic energy. When the steam pressure increases to a certain value, although the flow rate of the airflow through the nozzle no longer increases, but the pressure increases, the density of the airflow increases, and the kinetic energy increases accordingly. As for how high the pressure to choose when crushing depends on the crushability and fineness requirements of the material, when superheated steam is used to crush the titanium dioxide, the steam pressure is generally 0.8～1.7MPa, and the crushed and calcined materials are generally higher. The material can be lower.
- Temperature
Because of the increase in temperature, the flow rate of the gas can be increased. Take air as an example: the critical velocity at room temperature is 320m/s. When the temperature rises to 480℃, the critical velocity can be increased to 500m/s, that is, the kinetic energy increases by 150%. Increasing the temperature of the working fluid is beneficial to the crushing effect. When pulverizing titanium dioxide, the temperature of superheated steam is generally about 300-400℃. Usually, the temperature is higher when pulverizing the calcined material, and the temperature is lower when pulverizing the surface-treated material. Because some surface treatment agents, especially organic surface treatment agents, are not resistant to high temperatures, sometimes it is only necessary to overheat 100°C on the basis of the original steam temperature.
Note on jet mill:
(1) When the unloading equipment is in operation, the unloading outlet cannot be reached to avoid accidents.
(2) The speed of the impeller cannot exceed the specified speed, otherwise the temperature will be too high and the impeller and motor will be damaged.
(3) The safety valve should be checked regularly to ensure safety.
The jet mill is completely enclosed during the crushing process, and has a professional dust collection device, which will not cause dust leakage. This is a good equipment for many workshops that need to undergo environmental assessment transformation. This jet mill is widely used in chemical, mining, abrasives, refractory materials, battery materials, metallurgy, building materials, pharmaceuticals, ceramics, feed, new materials, environmental protection and other industries, as well as ultra-fine grinding and dispersing of various dry powder materials. And the performance of shaping particles is very good, which can fully meet the mesh size of ultra-fine crushing of various materials.